@font-face{font-family:Be Vietnam Pro;font-style:normal;font-display:swap;font-weight:400;src:url(/assets/be-vietnam-pro-vietnamese-400-normal-CRcqvyg1.woff2)format("woff2"),url(/assets/be-vietnam-pro-vietnamese-400-normal-BuGn0gnm.woff)format("woff")}@font-face{font-family:Be Vietnam Pro;font-style:normal;font-display:swap;font-weight:500;src:url(/assets/be-vietnam-pro-vietnamese-500-normal-DREgrEoJ.woff2)format("woff2"),url(/assets/be-vietnam-pro-vietnamese-500-normal-CfdwVo8-.woff)format("woff")}@font-face{font-family:Be Vietnam Pro;font-style:normal;font-display:swap;font-weight:600;src:url(/assets/be-vietnam-pro-vietnamese-600-normal-nyU-ZL2p.woff2)format("woff2"),url(/assets/be-vietnam-pro-vietnamese-600-normal-DkpCIyan.woff)format("woff")}@font-face{font-family:Be Vietnam Pro;font-style:normal;font-display:swap;font-weight:400;src:url(/assets/be-vietnam-pro-latin-400-normal-PpnXBOrz.woff2)format("woff2"),url(/assets/be-vietnam-pro-latin-400-normal-bXgqVju9.woff)format("woff")}@font-face{font-family:Be Vietnam Pro;font-style:normal;font-display:swap;font-weight:500;src:url(/assets/be-vietnam-pro-latin-500-normal-B6LVzGNe.woff2)format("woff2"),url(/assets/be-vietnam-pro-latin-500-normal-BJkVuMHw.woff)format("woff")}@font-face{font-family:Be Vietnam Pro;font-style:normal;font-display:swap;font-weight:600;src:url(/assets/be-vietnam-pro-latin-600-normal-BZDkUTrt.woff2)format("woff2"),url(/assets/be-vietnam-pro-latin-600-normal-5IO4e7bK.woff)format("woff")}@font-face{font-family:Literata;font-style:normal;font-display:swap;font-weight:400;src:url(/assets/literata-vietnamese-400-normal-H9pSqQsV.woff2)format("woff2"),url(/assets/literata-vietnamese-400-normal-BvhrDK3U.woff)format("woff")}@font-face{font-family:Literata;font-style:normal;font-display:swap;font-weight:500;src:url(/assets/literata-vietnamese-500-normal-BO6VJZmq.woff2)format("woff2"),url(/assets/literata-vietnamese-500-normal-oKjKEVoT.woff)format("woff")}@font-face{font-family:Literata;font-style:normal;font-display:swap;font-weight:400;src:url(/assets/literata-latin-400-normal-CLtNJ872.woff2)format("woff2"),url(/assets/literata-latin-400-normal-CUhpYSl8.woff)format("woff")}@font-face{font-family:Literata;font-style:normal;font-display:swap;font-weight:500;src:url(/assets/literata-latin-500-normal-Dbph1WrK.woff2)format("woff2"),url(/assets/literata-latin-500-normal-B-T_MU67.woff)format("woff")}:root{--paper:#fcfcff;--ink:#1e1b2e;--ink-2:#5b5770;--line:#e6e4f2;--line-2:#cfcbe6;--violet:#4b2fc9;--violet-soft:#efecfd;--mark:#ffec8a;--mark-soft:#fff8d1;--good:#0b7a5b;--surface:#fff;--on-mark:#1e1b2e;--violet-2:#8f7ce8;--warn-ink:#6a5a00;--ui:"Be Vietnam Pro", system-ui, sans-serif;--math:var(--ui);--sym:"Literata", Georgia, serif}@media (prefers-color-scheme:dark){:root:not([data-theme=light]){--paper:#15131f;--ink:#eceaf5;--ink-2:#a9a5bd;--line:#2a2738;--line-2:#443f5a;--violet:#a594ff;--violet-soft:#2a2547;--mark:#ffe36e;--mark-soft:#3a3314;--good:#5ad1ac;--surface:#1d1a2a;--warn-ink:#f1de86;--violet-2:#6e5ad0}}:root[data-theme=dark]{--paper:#15131f;--ink:#eceaf5;--ink-2:#a9a5bd;--line:#2a2738;--line-2:#443f5a;--violet:#a594ff;--violet-soft:#2a2547;--mark:#ffe36e;--mark-soft:#3a3314;--good:#5ad1ac;--surface:#1d1a2a;--warn-ink:#f1de86;--violet-2:#6e5ad0}*{box-sizing:border-box}html{-webkit-text-size-adjust:100%}body{background:var(--paper);color:var(--ink);font:400 17px/1.55 var(--ui);margin:0}button,input,select,textarea{font:inherit;color:inherit}h1,h2,h3{margin:0;font-weight:600;line-height:1.25}p{margin:0}:focus-visible{outline:3px solid var(--violet);outline-offset:2px;border-radius:4px}@media (prefers-reduced-motion:reduce){*{transition:none!important;animation:none!important}}.wrap{max-width:620px;margin:0 auto;padding:16px 20px 96px}.wide{max-width:1040px}.top{min-height:44px;color:var(--ink-2);justify-content:space-between;align-items:center;gap:12px;margin-bottom:28px;font-size:15px;display:flex}.brand{color:var(--ink);font-weight:600;text-decoration:none}.link{color:var(--ink-2);cursor:pointer;text-underline-offset:3px;text-decoration:underline;-webkit-text-decoration-color:var(--line-2);text-decoration-color:var(--line-2);background:0 0;border:0;min-height:40px;padding:8px 0}.stack>*+*{margin-top:16px}.muted{color:var(--ink-2)}.small{font-size:15px}.btn{border:1.5px solid var(--violet);background:var(--violet);min-height:52px;color:var(--paper);cursor:pointer;border-radius:10px;justify-content:center;align-items:center;width:100%;padding:0 24px;font-weight:500;display:inline-flex}.btn:disabled{background:var(--line);border-color:var(--line);color:var(--ink-2);cursor:default}.btn.quiet{color:var(--violet);background:0 0}.btn.quiet:hover{background:var(--violet-soft)}.row{gap:10px;display:flex}.row>*{flex:1}.page{background-image:linear-gradient(var(--line) 1px, transparent 1px), linear-gradient(90deg, var(--line) 1px, transparent 1px);box-shadow:inset 3px 0 0 var(--violet);background-position:-1px -1px;background-size:28px 28px;border-radius:4px;padding:24px 20px;position:relative}.page>.ink{background:var(--paper);-webkit-box-decoration-break:clone;box-decoration-break:clone;padding:2px 6px}.frac{vertical-align:middle;text-align:center;line-height:1.12;font-family:var(--math);font-variant-numeric:lining-nums;flex-direction:column;margin:0 2px;display:inline-flex}.frac>span:first-child{border-bottom:1.5px solid;padding:0 4px 1px}.frac>span:last-child{padding:1px 4px 0}.bar{gap:2px;width:100%;max-width:420px;height:34px;display:flex}.bar i{background:var(--surface);box-shadow:inset 0 0 0 1.5px var(--line-2);flex:1}.bar i.on{background:var(--violet);box-shadow:none}.bars{gap:10px;display:grid}.barline{grid-template-columns:56px 1fr;align-items:center;gap:10px;font-size:20px;display:grid}.opt{border:1.5px solid var(--line-2);background:var(--surface);text-align:left;cursor:pointer;border-radius:10px;align-items:center;gap:14px;width:100%;min-height:56px;padding:10px 16px;font-size:19px;display:flex}.opt:hover{border-color:var(--violet)}.opt.sel{border-color:var(--violet);background:var(--violet-soft)}.opt.placed{color:var(--ink-2);background:var(--paper);border-style:dashed}.opts{gap:10px;display:grid}.num{width:100%;min-height:60px;font:500 26px var(--math);text-align:center;border:1.5px solid var(--line-2);background:var(--surface);border-radius:10px}.num:focus{border-color:var(--violet);box-shadow:0 0 0 3px var(--violet-soft);outline:0}.fracinput{gap:6px;width:132px;margin:0 auto;display:grid}.fracinput hr{border:0;border-top:2.5px solid var(--ink);width:100%;margin:0}.field{gap:6px;display:grid}.field>span{color:var(--ink-2);font-size:15px}.text{border:1.5px solid var(--line-2);background:var(--surface);border-radius:10px;width:100%;min-height:50px;padding:0 14px}textarea.text{min-height:96px;padding:12px 14px;font-family:ui-monospace,monospace;font-size:14px}.matchgrid{grid-template-columns:1fr 1fr;gap:10px;display:grid}.ordernum{background:var(--violet);width:28px;height:28px;color:var(--paper);font:500 15px var(--ui);border-radius:50%;flex:none;justify-content:center;align-items:center;display:inline-flex}.mark{color:var(--on-mark);background:var(--mark);-webkit-box-decoration-break:clone;box-decoration-break:clone;border-radius:2px;padding:1px 5px}.note{background:var(--mark-soft);border-radius:8px;padding:14px 16px}.good{color:var(--good);font-weight:600}.chain{margin:0;padding:0;list-style:none;display:grid}.chain li{padding:10px 0 10px 28px;position:relative}.chain li:before{content:"";background:var(--paper);width:10px;height:10px;box-shadow:0 0 0 1.5px var(--line-2);z-index:1;border-radius:50%;position:absolute;top:18px;left:7px}.chain li+li:after{content:"";background:var(--line-2);width:1.5px;height:36px;position:absolute;top:-18px;left:11.25px}.chain li.done:before{background:var(--violet);box-shadow:0 0 0 1.5px var(--violet)}.chain li.gap:before{background:var(--mark);box-shadow:0 0 0 1.5px #b59a00}.chain .state{color:var(--ink-2);font-size:14px;display:block}.chain button{cursor:pointer;text-align:left;background:0 0;border:0;padding:0}.sure{grid-template-columns:repeat(3,1fr);gap:8px;display:grid}.sure button{border:1.5px solid var(--violet);background:var(--surface);min-height:52px;color:var(--violet);cursor:pointer;border-radius:10px;padding:4px;font-size:15px;font-weight:500}.sure button:hover{background:var(--violet-soft)}.progress{background:var(--line);border-radius:2px;height:3px;overflow:hidden}.progress>i{background:var(--violet);height:100%;transition:width .25s;display:block}.steps{margin:0;padding-left:22px}.steps li{margin:8px 0}.steps li::marker{color:var(--violet)}.reveal{animation:.22s ease-out reveal}@keyframes reveal{0%{opacity:0;transform:translateY(4px)}}.tabs{border-bottom:1px solid var(--line);gap:20px;margin-bottom:28px;display:flex;overflow-x:auto}.tabs button{cursor:pointer;color:var(--ink-2);white-space:nowrap;background:0 0;border:0;border-bottom:2px solid #0000;min-height:44px;margin-bottom:-1px;padding:10px 0}.tabs button.on{color:var(--ink);border-color:var(--violet);font-weight:500}.facts{grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:24px 20px;margin:8px 0 36px;display:grid}.fact b{font-variant-numeric:tabular-nums;font-size:30px;font-weight:500;line-height:1.2;display:block}.fact span{color:var(--ink-2);font-size:14px}.sect h2{margin-bottom:4px;font-size:18px}.sect>p{color:var(--ink-2);max-width:68ch;margin-bottom:14px;font-size:15px}.chart{gap:5px;font-size:14px;display:grid}.chart .r{grid-template-columns:110px 1fr 58px;align-items:center;gap:10px;display:grid}.chart .track{height:14px}.chart .fill{background:var(--violet);border-radius:0 4px 4px 0;min-width:2px;height:100%;display:block}.chart .v{text-align:right;font-variant-numeric:tabular-nums}.hours{border-bottom:1px solid var(--line-2);grid-template-columns:repeat(24,1fr);align-items:end;gap:2px;height:96px;display:grid}.hours i{background:var(--violet);border-radius:4px 4px 0 0;min-height:0;display:block}.hourlabels{color:var(--ink-2);justify-content:space-between;margin-top:4px;font-size:13px;display:flex}.scroll{overflow-x:auto}table{border-collapse:collapse;width:100%;font-size:14.5px}th{text-align:left;color:var(--ink-2);border-bottom:1px solid var(--line-2);white-space:nowrap;padding:8px 12px 8px 0;font-weight:500}td{border-bottom:1px solid var(--line);vertical-align:top;padding:10px 12px 10px 0}td.n,th.n{text-align:right;font-variant-numeric:tabular-nums}tr.click{cursor:pointer}tr.click:hover td{background:var(--violet-soft)}.chip{background:var(--violet-soft);color:var(--violet);white-space:nowrap;border-radius:20px;padding:1px 8px;font-size:13px;display:inline-block}.chip.warn{background:var(--mark-soft);color:var(--warn-ink)}.signal{border-top:1px solid var(--line);padding:14px 0}.signal b{font-weight:500}.banner{background:var(--mark-soft);border-radius:8px;margin-bottom:24px;padding:12px 16px;font-size:15px}.check{align-items:flex-start;gap:10px;padding:6px 0;font-size:15px;display:flex}.check input{width:18px;height:18px;accent-color:var(--violet);flex:none;margin-top:5px}.btn.inline{width:auto;min-height:44px;padding:0 18px}.toolbar{flex-wrap:wrap;align-items:center;gap:10px;margin-bottom:18px;display:flex}.toolbar select{border:1.5px solid var(--line-2);background:var(--surface);border-radius:8px;min-height:44px;padding:0 10px}@media (width<=480px){.wrap{padding:12px 16px 72px}.prompt{font-size:20px}.chart .r{grid-template-columns:84px 1fr 48px}}.stages{gap:4px;margin-bottom:20px;display:flex}.stages i{background:var(--line);border-radius:2px;flex:1;height:3px}.stages i.on{background:var(--violet)}.hook{font:400 21px/1.55 var(--math)}.real{margin:0;padding-left:20px}.real li{margin:6px 0}.doit{border-left:3px solid var(--mark);padding:4px 0 4px 14px}.doit b{font-weight:500;display:block}.demo{border:1.5px solid var(--line-2);background:var(--surface);border-radius:10px;gap:14px;padding:16px;display:grid}.demo .readout{font:400 22px/1.5 var(--math);text-align:center;min-height:44px}.chips{flex-wrap:wrap;gap:8px;display:flex}.chips button{border:1.5px solid var(--line-2);background:var(--surface);cursor:pointer;border-radius:22px;min-width:44px;min-height:44px;padding:0 14px}.chips button.on{background:var(--violet);border-color:var(--violet);color:var(--paper)}input[type=range]{width:100%;height:32px;accent-color:var(--violet)}.pieces{gap:2px;width:100%;display:grid}.pieces button{aspect-ratio:1.25;background:var(--line);cursor:pointer;border:0;padding:0}.pieces button.on{background:var(--violet)}.choco button{background:#e2d6f5}.area{aspect-ratio:1.5;background:var(--line-2);gap:1px;width:100%;max-width:360px;margin:0 auto;padding:1px;display:grid}.area i{background:var(--surface)}.area i.a{background:var(--violet-soft)}.area i.b{background:var(--mark-soft)}.area i.ab{background:var(--violet)}.dots{gap:10px;display:grid}.dots .grp{border:1.5px dashed var(--line-2);border-radius:8px;flex-wrap:wrap;gap:5px;padding:8px;display:flex}.dots .grp.on{border-style:solid;border-color:var(--violet);background:var(--violet-soft)}.dots b{background:var(--line-2);border-radius:50%;width:15px;height:15px}.dots .on b{background:var(--violet)}.timeline{width:100%;height:auto;display:block}.formula{font:400 24px/1.6 var(--math);text-align:center;border-top:1.5px solid var(--line-2);border-bottom:1.5px solid var(--line-2);padding:16px 8px}.frac span{white-space:nowrap}.glimpse{pointer-events:none;padding:10px 16px calc(10px + env(safe-area-inset-bottom));background:linear-gradient(transparent, var(--paper) 35%);color:var(--ink-2);font:400 18px/1.5 var(--math);justify-content:center;animation:6s both glimpse;display:flex;position:fixed;bottom:0;left:0;right:0}@keyframes glimpse{0%{opacity:0}12%{opacity:.9}80%{opacity:.9}to{opacity:0}}@media (prefers-reduced-motion:reduce){.glimpse{opacity:.9}}.search{border:1.5px solid var(--line-2);background:var(--surface);border-radius:10px;width:100%;min-height:54px;padding:0 16px;font-size:18px}.search:focus{border-color:var(--violet);box-shadow:0 0 0 3px var(--violet-soft);outline:0}.results{margin:0;padding:0;list-style:none}.results li{border-top:1px solid var(--line)}.results a{color:inherit;min-height:48px;padding:12px 0;text-decoration:none;display:block}.results a:hover b{color:var(--violet)}.results b{font-weight:500;display:block}.results span{color:var(--ink-2);font-size:14.5px}.toplinks{align-items:center;gap:18px;display:flex}.textlink{color:var(--violet);text-underline-offset:3px}.sectiongap>*+*{margin-top:34px}.sectiongap h2{margin-bottom:10px;font-size:18px}.pct{grid-template-columns:repeat(10,1fr);gap:2px;width:100%;max-width:300px;margin:0 auto;display:grid}.pct i{aspect-ratio:1;background:var(--line)}.pct i.on{background:var(--violet)}.grades{gap:8px;margin-bottom:24px;display:flex}.grades button{border:1.5px solid var(--line-2);background:var(--surface);cursor:pointer;border-radius:10px;flex:1;min-height:48px;font-weight:500}.grades button[aria-pressed=true]{background:var(--violet);border-color:var(--violet);color:var(--paper)}.courseline{color:var(--ink-2);justify-content:space-between;align-items:baseline;gap:12px;margin-bottom:8px;font-size:15px;display:flex}.chapter>summary{cursor:pointer;grid-template-columns:1fr auto;align-items:center;gap:4px 14px;min-height:56px;padding:14px 0;list-style:none;display:grid}.chapter>summary::-webkit-details-marker{display:none}.chapter>summary b{font-weight:500}.chapter>summary span{color:var(--ink-2);font-variant-numeric:tabular-nums;font-size:14px}.chapter>summary .progress{grid-column:1/-1}.skills{margin:0;padding:0 0 12px;list-style:none}.skills li{grid-template-columns:12px 1fr auto;align-items:center;gap:12px;min-height:48px;padding:7px 0;display:grid}.skills .dot{width:10px;height:10px;box-shadow:0 0 0 1.5px var(--line-2);border-radius:50%}.skills .dot.done{background:var(--violet);box-shadow:0 0 0 1.5px var(--violet)}.skills .dot.gap{background:var(--mark);box-shadow:0 0 0 1.5px #b59a00}.skills small{color:var(--ink-2);font-size:13.5px;display:block}.skills a.name{color:inherit;text-underline-offset:3px;-webkit-text-decoration-color:var(--line-2);text-decoration-color:var(--line-2)}.skills .soon{color:var(--ink-2)}.minibtn{border:1.5px solid var(--line-2);background:var(--surface);min-height:44px;color:var(--violet);cursor:pointer;white-space:nowrap;border-radius:8px;padding:0 14px;font-size:15px}.minibtn:hover{border-color:var(--violet)}body{font-size:18px}.wrap{max-width:560px}.link{color:var(--ink-2);text-decoration:none}.link:hover{color:var(--violet)}.brand{font-size:16px}.qbox{padding:4px 0 8px}.prompt{font:400 24px/1.5 var(--math)}h1.big{font:500 36px/1.2 var(--math);margin-bottom:8px}.hero-action h1{font-size:30px;line-height:1.25}.fig{width:100%;max-width:300px;height:auto;margin:0 auto 4px;display:block}.fig.small{max-width:190px;margin-bottom:10px}.hook{font-size:22px}.formula{border:0;padding:12px 0;font-size:28px}.bigok{font:500 34px/1.2 var(--math);color:var(--good)}.askfoot{flex-wrap:wrap;justify-content:space-between;gap:10px;display:flex}.askfoot .btn{flex:140px;width:auto;min-height:46px}.why>summary{cursor:pointer;color:var(--ink-2);align-items:center;min-height:44px;font-size:16px;display:flex}.nextup{color:var(--ink-2);margin:0;padding:0;list-style:none}.nextup li{padding:6px 0}.footlinks{flex-wrap:wrap;gap:4px 20px;margin-top:44px;display:flex}.course{margin-top:14px}.chapter{border-top:1px solid var(--line)}.chapter>summary{grid-template-columns:1fr auto}.skills li{grid-template-columns:12px 1fr auto}.skills a.name{text-decoration:none}.results li{border:0}.opt{font-size:20px}.grades{margin-bottom:18px}.sect{margin-top:30px}.reveal{animation-duration:.18s}.stagename{font-size:15px}.decs{font:400 28px/1.5 var(--math);text-align:right;font-variant-numeric:tabular-nums;width:150px;margin:0 auto}.decs hr{border:0;border-top:2px solid var(--ink);margin:4px 0}:root{--soft:cubic-bezier(.2,.8,.2,1);--spring:linear(0, .009, .035 2.1%, .141, .281 6.7%, .723 12.9%, .938 16.7%, 1.017, 1.077, 1.121, 1.149 24.3%, 1.159, 1.163, 1.161, 1.154 29.9%, 1.129 32.8%, 1.051 39.6%, 1.017 43.1%, .991, .977 51%, .974 53.8%, .975 57.1%, .997 69.8%, 1.003 76.9%, 1.004 83.8%, 1)}.wrap{flex-direction:column;min-height:100svh;display:flex}.wrap>*{flex:none}.wrap>.screen{flex:1}.wrap:has(>.screen){padding-bottom:max(24px, env(safe-area-inset-bottom))}.stack.screen{flex-direction:column;gap:18px;display:flex}.stack.screen>*+*{margin-top:0}.stack.screen>*{flex:none}.stack.screen>.stagebody{flex-direction:column;gap:18px;display:flex}.stack.screen>.stagebody>*+*{margin-top:0}.stack.screen>.cta{animation:rise .4s .16s var(--soft) both;gap:4px;margin-top:auto;display:grid}.cta .link{text-align:center}@media (width>=700px),(height>=1000px){.stack.screen>.cta{margin-top:12px}}@keyframes rise{0%{opacity:0;transform:translateY(10px)}}.reveal,.stagebody{animation:slidein .34s var(--soft) both}@keyframes slidein{0%{opacity:0;transform:translate(22px)}}.btn{transition:transform .28s var(--spring), background-color .18s, color .18s, border-color .18s;touch-action:manipulation;border-radius:14px;font-size:18px}.btn:hover{filter:none}@media (hover:hover){.btn:not(.quiet):not(:disabled):hover{background:color-mix(in srgb, var(--violet) 86%, var(--ink));border-color:#0000}}.btn:active:not(:disabled),.sure button:active,.chips button:active,.grades button:active,.minibtn:active{transition-duration:60ms;transform:scale(.96)}.sure button,.chips button,.grades button,.minibtn{transition:transform .28s var(--spring), background-color .18s, color .18s, border-color .18s;touch-action:manipulation}.opt{isolation:isolate;transition:transform .28s var(--spring), border-color .18s;touch-action:manipulation;border-radius:14px;position:relative;overflow:hidden}.opt:before{content:"";z-index:-1;background:var(--violet-soft);clip-path:circle(0 at var(--x,50%) var(--y,50%));transition:clip-path .42s var(--soft);position:absolute;inset:0}.opt.sel{background:var(--surface)}.opt.sel:before{clip-path:circle(150% at var(--x,50%) var(--y,50%))}.opt:active{transition-duration:60ms;transform:scale(.98)}.ordernum{animation:pop .34s var(--spring) both}@keyframes pop{0%{transform:scale(0)}}.num,.text,.search{transition:border-color .18s, box-shadow .22s var(--soft);border-radius:14px}.num:focus,.text:focus,.search:focus{box-shadow:0 0 0 5px var(--violet-soft)}.note{animation:slidein .28s var(--soft) both;border-radius:12px}.mark{background:linear-gradient(var(--mark), var(--mark)) no-repeat 0 0 / 100% 100%;animation:sweep .46s .18s var(--soft) backwards}@keyframes sweep{0%{background-size:0 100%}}.formula,.steps li{animation:.62s ease-out 80ms backwards write}@keyframes write{0%{clip-path:inset(0 100% 0 0)}to{clip-path:inset(-8px -8px -8px 0)}}.trail{margin-bottom:18px;padding:22px 15px 6px}.trail-line{background:var(--line);border-radius:2px;height:3px;position:relative}.trail-line>i{background:var(--violet);transition:width .52s var(--soft);border-radius:2px;display:block;position:absolute;inset:0 auto 0 0}.trail-line>b{background:var(--line-2);border-radius:50%;width:7px;height:7px;margin:-3.5px 0 0 -3.5px;transition:background-color .3s .2s;position:absolute;top:50%}.trail-line>b.on{background:var(--violet)}.trail-cham{transition:left .52s var(--soft);line-height:0;position:absolute;bottom:-2px;transform:translate(-50%)}.trail-hop{transform-origin:50% 100%;display:block}.trailnote{color:var(--ink-2);margin:-10px 0 20px;font-size:15px}.cham{display:block;overflow:visible}.cham-eyes{transform-box:fill-box;transform-origin:50%;transition:translate .3s var(--soft);animation:5.6s infinite blink}@keyframes blink{0%,95%,to{transform:scaleY(1)}97.5%{transform:scaleY(.1)}}.cham-body{transform-box:fill-box;transform-origin:50% 100%;transition:rotate .4s var(--spring)}.hero-cham{transform-origin:50% 100%;width:68px;animation:popup .5s var(--spring) both;display:block}@keyframes popup{0%{opacity:0;transform:scale(.4)}}.bigok{align-items:center;gap:12px;display:flex}.check-mark{flex:none;width:40px;height:40px;position:relative}.check-mark svg{display:block;overflow:visible}.check-mark path{fill:none;stroke:var(--good);stroke-width:5px;stroke-linecap:round;stroke-linejoin:round;stroke-dasharray:1;animation:checkdraw .44s 60ms var(--soft) backwards}@keyframes checkdraw{0%{stroke-dashoffset:1px}to{stroke-dashoffset:0}}.burst{position:absolute;top:50%;left:50%}.burst i{background:var(--violet);opacity:0;width:8px;height:8px;animation:burst .78s .26s var(--soft);border-radius:50%;margin:-4px;position:absolute}.burst i.y{background:var(--mark);box-shadow:0 0 0 1px var(--ink)}@keyframes burst{0%{opacity:1;transform:rotate(var(--a)) translateX(4px) scale(1)}70%{opacity:1}to{opacity:0;transform:rotate(var(--a)) translateX(var(--d)) scale(.5)}}.walk{height:92px;margin:4px 0 6px;position:relative}.walk-line{background:var(--line-2);border-radius:2px;height:3px;position:absolute;bottom:20px;left:8%;right:8%}.walk-line>b{background:var(--line-2);border-radius:50%;width:9px;height:9px;margin:-4.5px;position:absolute;top:50%}.walk-line>em{background:var(--mark);width:44px;height:44px;animation:popup .5s 1.2s var(--spring) backwards;border-radius:50%;margin:-22px;position:absolute;top:50%;left:0}.walk-cham{margin-left:-18px;line-height:0;animation:1.25s ease-in-out .25s backwards walkback;position:absolute;bottom:20px;left:8%}@keyframes walkback{0%{left:92%;transform:translateY(0)}12%{transform:translateY(-11px)}25%{left:72%;transform:translateY(0)}37%{transform:translateY(-11px)}50%{left:50%;transform:translateY(0)}62%{transform:translateY(-11px)}75%{left:29%;transform:translateY(0)}87%{transform:translateY(-11px)}to{left:8%;transform:translateY(0)}}.demo{background:0 0;border:0;padding:0}.demo-life{display:block}.demo .readout{transform-origin:50%;font-size:26px}.demo svg rect,.demo svg circle{transition:x .32s var(--soft), y .32s var(--soft), width .32s var(--soft), height .32s var(--soft), cx .32s var(--soft), cy .32s var(--soft), r .32s var(--spring), fill .2s}.demo svg path{transition:d .32s var(--soft), stroke .2s}.bar i,.pct i,.area i,.pieces button,.dots b{transition:background-color .22s,box-shadow .22s}.demo .pct i,.demo .dots b{animation:pop .3s var(--spring) backwards}.chips button{transition:transform .28s var(--spring), background-color .2s, color .2s, border-color .2s}.demo .say{font-size:17px}input[type=range]{appearance:none;cursor:grab;touch-action:pan-y;background:0 0;height:44px;margin:0}input[type=range]::-webkit-slider-runnable-track{background:linear-gradient(90deg, var(--violet) var(--p,50%), var(--line) var(--p,50%));border-radius:3px;height:6px}input[type=range]::-moz-range-track{background:var(--line);border-radius:3px;height:6px}input[type=range]::-moz-range-progress{background:var(--violet);border-radius:3px;height:6px}input[type=range]::-webkit-slider-thumb{-webkit-appearance:none;background:var(--violet);border:4px solid var(--paper);width:30px;height:30px;box-shadow:0 0 0 1.5px var(--violet);transition:transform .24s var(--spring);border-radius:50%;margin-top:-12px}input[type=range]::-moz-range-thumb{background:var(--violet);border:4px solid var(--paper);width:22px;height:22px;box-shadow:0 0 0 1.5px var(--violet);transition:transform .24s var(--spring);border-radius:50%}input[type=range]:active{cursor:grabbing}input[type=range]:active::-webkit-slider-thumb{transform:scale(1.2)}input[type=range]:active::-moz-range-thumb{transform:scale(1.2)}details[open]>:not(summary){animation:slidein .28s var(--soft) both}.why>summary,.chapter>summary{transition:color .18s}.fig{max-width:340px}.fig.small{max-width:190px}.hero-action h1{font:500 33px/1.2 var(--math);letter-spacing:-.01em}.top{margin-bottom:8px}@media (prefers-reduced-motion:reduce){.burst{display:none}}html,body{overflow-x:clip}.appbar{z-index:20;background:var(--paper);border-bottom:1px solid var(--line);position:sticky;top:0}.appbar-in{justify-content:space-between;align-items:center;gap:20px;max-width:1120px;min-height:60px;margin:0 auto;padding:0 20px;display:flex}.brandmark{white-space:nowrap;align-items:center;gap:8px;font-size:17px;display:inline-flex}.publiclinks{gap:18px;font-size:16px;display:flex}.publiclinks a{color:var(--ink-2);padding:10px 0;text-decoration:none}.publiclinks a:hover{color:var(--violet)}.mainnav{z-index:20;background:var(--paper);border-top:1px solid var(--line);padding-bottom:env(safe-area-inset-bottom);grid-template-columns:repeat(4,1fr);display:grid;position:fixed;inset:auto 0 0}.mainnav a{min-height:58px;color:var(--ink-2);justify-items:center;gap:2px;padding:8px 2px 7px;font-size:12.5px;font-weight:500;text-decoration:none;display:grid}.mainnav svg{fill:none;stroke:currentColor;stroke-width:2px;stroke-linecap:round;stroke-linejoin:round}.mainnav a[aria-current=page]{color:var(--violet)}.mainnav a[aria-current=page] svg{fill:var(--violet-soft)}.shell .wrap{min-height:0;padding-bottom:100px}.pagetitle{font:500 32px/1.2 var(--math);margin-bottom:18px}.smallhead{font:500 16px var(--ui);color:var(--ink-2);margin-bottom:8px}.wrap.narrow{max-width:460px;min-height:0;padding-top:28px}.wrap.roomy{padding-top:28px}.startscreen{gap:18px;display:grid}.startscreen h1{font-size:34px}.threesteps{counter-reset:st;gap:10px;margin:6px 0 10px;padding:0;list-style:none;display:grid}.threesteps li{counter-increment:st;grid-template-columns:34px 90px 1fr;align-items:center;gap:10px;display:grid}.threesteps li:before{content:counter(st);background:var(--violet);width:34px;height:34px;color:var(--paper);border-radius:50%;place-items:center;font-weight:600;display:grid}.threesteps b{font-size:18px;font-weight:500;line-height:1.3}.stepart{width:90px;height:auto;display:block}.btn.big{min-height:60px;font-size:20px}.todaycard{flex-direction:column-reverse;gap:12px;display:flex}.today-text{gap:12px;display:grid}.today-text .btn{margin-top:6px}.nextstops{color:var(--ink-2);margin:0;padding:0;list-style:none}.nextstops li{padding:8px 0 8px 24px;position:relative}.nextstops li:before{content:"";width:9px;height:9px;box-shadow:0 0 0 2px var(--line-2);background:var(--paper);border-radius:50%;position:absolute;top:17px;left:4px}.nextstops li+li:after{content:"";background:var(--line-2);width:2px;height:22px;position:absolute;top:-6px;left:8px}.coach{background:var(--mark-soft);animation:slidein .3s var(--soft) both;border-radius:12px;align-items:flex-start;gap:10px;padding:10px 12px;font-size:16px;line-height:1.4;display:flex}.coach svg{flex:none}.num::placeholder{color:var(--line-2);font-size:20px}.stepline{font:500 19px/1.35 var(--ui);margin-top:-8px}.stagename{color:var(--ink-2);font-size:14px}.askgrid>*+*{margin-top:20px}.askfoot .link{color:var(--violet)}@media (width>=860px){.appbar-in{min-height:68px}.mainnav{background:0 0;border:0;gap:6px;padding:0;display:flex;position:static}.mainnav a{border-radius:10px;align-items:center;gap:8px;min-height:44px;padding:0 14px;font-size:16px;transition:background-color .15s,color .15s;display:flex}.mainnav svg{width:20px;height:20px}.mainnav a:hover{background:var(--violet-soft);color:var(--violet)}.mainnav a[aria-current=page]{background:var(--violet-soft)}.shell .wrap{padding-bottom:64px}.wrap.roomy{max-width:1040px;padding-top:48px}.wrap.session{max-width:1040px;padding-top:28px}.pagetitle{margin-bottom:24px;font-size:40px}.btn{width:auto;min-width:220px;padding:0 32px}form .btn,.wrap.narrow .btn{width:100%}.startscreen{text-align:center;justify-items:center;gap:24px;padding-top:12px}.startscreen h1{font-size:48px}.threesteps{grid-template-columns:repeat(3,1fr);gap:32px;width:100%;margin:20px 0}.threesteps li{grid-template-columns:1fr;justify-items:center;gap:14px}.stepart{width:180px}.threesteps b{font-size:20px}.startscreen .link{width:auto!important}.todaycard{flex-direction:row;justify-content:space-between;align-items:center;gap:64px;padding:24px 0 40px}.today-text{flex:50%;justify-items:start}.today-text h1{font-size:46px}.today-art{flex:50%}.today-art .fig{max-width:460px}.nextstops{gap:40px;display:flex}.nextstops li+li:after{display:none}.askgrid{grid-template-columns:1.15fr .85fr;align-items:center;gap:72px;min-height:52vh;display:grid}.askgrid>*+*{margin-top:0}.askp .btn{width:100%}.askgrid .prompt{font-size:32px;line-height:1.4}.stack.screen>.stagebody{grid-template-columns:1fr 1fr;align-items:center;gap:56px;min-height:44vh;display:grid}.stagebody>:only-child{grid-column:1/-1;width:100%;max-width:680px;margin-inline:auto}.stagebody .hook{font-size:28px}.stagebody .fig{max-width:440px}.stagebody .formula{grid-column:1/-1;font-size:40px}.stack.screen>.cta{justify-items:end;margin-top:24px}.wrap.session>[data-screen=verdict],.wrap.session>[data-screen=right],.wrap.session>[data-screen=probe-intro],.wrap.session>[data-screen=lesson-done],.wrap.session>[data-screen=done],.wrap[data-screen=result]>.screen{width:100%;max-width:620px;margin-inline:auto}.wrap.session .hero-action>.cta,.wrap.session>[data-screen]>.cta{justify-items:stretch}.wrap.session>[data-screen]>.cta .btn{width:100%}.wrap.session>[data-screen=lesson]>.cta{justify-items:end}.wrap.session>[data-screen=lesson]>.cta .btn{width:auto}.course{grid-template-columns:1fr 1fr;align-items:start;gap:0 48px;display:grid}.grades{max-width:520px}.results{columns:2;column-gap:48px}.results li{break-inside:avoid}.stagebody .formula+p{text-align:center;grid-column:1/-1}}.exitbtn,.backlink{border:1.5px solid var(--ink-2);background:var(--surface);min-height:44px;color:var(--ink);cursor:pointer;white-space:nowrap;transition:transform .28s var(--spring), border-color .15s, background-color .15s, color .15s;touch-action:manipulation;border-radius:10px;flex:none;align-items:center;gap:6px;padding:0 14px 0 10px;font-size:16px;font-weight:500;text-decoration:none;display:inline-flex}.exitbtn svg,.backlink svg{fill:none;stroke:currentColor;stroke-width:2.4px;stroke-linecap:round;stroke-linejoin:round}.exitbtn:hover,.backlink:hover{border-color:var(--violet);color:var(--violet);background:var(--violet-soft)}.exitbtn:active,.backlink:active{transition-duration:60ms;transform:scale(.96)}.top{min-height:48px;margin-bottom:10px}.progresslabel{color:var(--ink);text-align:right;font-size:16px;font-weight:500}.link{min-height:44px;color:var(--violet);text-decoration:underline;-webkit-text-decoration-color:color-mix(in srgb, var(--violet) 35%, transparent);text-decoration-color:color-mix(in srgb, var(--violet) 35%, transparent);text-underline-offset:4px;font-weight:500}.btn.quiet{border-width:1.5px}.askfoot{grid-auto-columns:1fr;grid-auto-flow:column;gap:10px;display:grid}.askfoot .btn{width:100%;min-width:0;min-height:48px;padding:0 10px;font-size:16px}.num::placeholder{color:var(--ink-2);font-size:18px;font-weight:400}.brandmark{min-height:44px}.mainnav a{font-size:14px}.sectiongap a,.textlink{align-items:center;min-height:44px;font-weight:500;display:inline-flex}.opt:disabled{cursor:default;opacity:1}@media (width>=860px){.mainnav a{font-size:16px}}.skills a.name{padding:10px 0;display:block}.appbar-in{justify-content:flex-start;gap:14px;max-width:1280px;min-height:66px;padding:6px 16px}.brandmark .cham{flex:none}.searchbar{background:var(--surface);border:1.5px solid var(--line-2);min-width:0;min-height:46px;transition:border-color .15s, box-shadow .2s var(--soft);border-radius:23px;flex:auto;align-items:center;gap:10px;padding:0 16px;display:flex;position:relative}.searchbar svg{fill:none;stroke:var(--ink-2);stroke-width:2px;stroke-linecap:round;flex:none}.searchbar:focus-within{border-color:var(--violet);box-shadow:0 0 0 4px var(--violet-soft)}.searchbar input{background:0 0;border:0;outline:0;flex:1;min-width:0;height:42px;font-size:16px}.searchbar input::placeholder{color:var(--ink-2)}.searchbar input::-webkit-search-cancel-button{cursor:pointer}.suggest{z-index:30;background:var(--surface);border:1.5px solid var(--line-2);box-shadow:0 12px 32px color-mix(in srgb, var(--ink) 16%, transparent);animation:rise .18s var(--soft) both;border-radius:16px;margin:0;padding:6px;list-style:none;position:absolute;top:calc(100% + 6px);left:0;right:0}.suggest li{cursor:pointer;border-radius:10px;min-height:44px;padding:10px 12px}.suggest li:hover,.suggest li.on{background:var(--violet-soft)}.suggest b{font-size:16px;font-weight:500;display:block}.suggest small{color:var(--ink-2);font-size:14px;display:block}.publiclinks{flex:none}.hero-cham{width:84px}.profilehead{justify-content:space-between;align-items:baseline;gap:12px;display:flex}.segment{background:var(--line);border-radius:14px;grid-template-columns:1fr 1fr;gap:4px;max-width:420px;margin-bottom:20px;padding:4px;display:grid}.segment button{min-height:44px;color:var(--ink-2);cursor:pointer;background:0 0;border:0;border-radius:10px;font-weight:500;transition:background-color .18s,color .18s}.segment button[aria-selected=true]{background:var(--surface);color:var(--violet)}.profilegrid{align-items:start;gap:14px;display:grid}.panel{background:var(--surface);border:1.5px solid var(--line);border-radius:16px;gap:12px;min-width:0;padding:18px;display:grid}.panel h2{font:500 18px/1.3 var(--ui)}.statrow{grid-template-columns:repeat(2,1fr);gap:16px;margin:0 0 4px}.fact b{font-family:var(--math);font-size:36px}.fact span{font-size:15px}.activity-bars{border-bottom:1.5px solid var(--line-2);grid-template-columns:repeat(14,1fr);align-items:end;gap:3px;height:90px;display:grid}.activity-bars i{background:var(--violet);animation:growup .5s var(--soft) backwards;transform-origin:bottom;border-radius:3px 3px 0 0;display:block}@keyframes growup{0%{transform:scaleY(0)}}.activity-axis{color:var(--ink-2);justify-content:space-between;margin-top:4px;font-size:14px;display:flex}.plainlist{margin:0;padding:0;list-style:none}.plainlist li{border-top:1px solid var(--line);padding:8px 0}.plainlist li:first-child{border-top:0}.recent span{display:block}.recent small{color:var(--ink-2);font-size:14px}.chapterbars{gap:12px;margin:0;padding:0;list-style:none;display:grid}.chapterbars li{grid-template-columns:1fr auto;gap:4px 10px;font-size:16px;display:grid}.chapterbars b{font-variant-numeric:tabular-nums;font-weight:500}.chapterbars .progress{grid-column:1/-1;height:5px}.infolist{grid-template-columns:auto 1fr;gap:6px 16px;margin:0;display:grid}.infolist dt{color:var(--ink-2)}.infolist dd{margin:0;font-weight:500}.panel .trail{margin:0}.panel .grades{max-width:none;margin:0}.panel .btn{width:100%}@media (width>=620px){.statrow{grid-template-columns:repeat(4,1fr)}}@media (width>=860px){.appbar-in{gap:20px;min-height:72px;padding:6px 24px}.mainnav{flex:none;gap:4px;display:flex}.mainnav a{white-space:nowrap;padding:0 12px}.searchbar{border-radius:25px;min-height:50px}.profilegrid{grid-template-columns:repeat(2,1fr);gap:18px}.statrow{grid-column:1/-1}}@media (width>=1180px){.brandmark span{display:inline}.wrap.roomy{max-width:1120px}}.trail{padding-top:40px}.panel .trail{padding-top:34px}.brandmark{justify-content:center;min-width:44px}:root{--cham-1:#a997ff;--cham-2:#5a3be0;--cham-3:#2a1590;--eye-x:0px;--eye-y:0px}@media (prefers-color-scheme:dark){:root:not([data-theme=light]){--cham-1:#d3c9ff;--cham-2:#8069f2;--cham-3:#4227b8}}:root[data-theme=dark]{--cham-1:#d3c9ff;--cham-2:#8069f2;--cham-3:#4227b8}:root[data-theme=light]{--cham-1:#a997ff;--cham-2:#5a3be0;--cham-3:#2a1590}.cham{overflow:visible}.cham-body{transform-box:view-box;transform-origin:28px 40px;transition:rotate .4s var(--spring);animation:3.2s ease-in-out infinite chambreathe}@keyframes chambreathe{0%,to{transform:translateY(0)scale(1)}50%{transform:translateY(-1.3px)scale(1.012,.988)}}.cham-shadow{transform-box:fill-box;transform-origin:50%;animation:3.2s ease-in-out infinite chamshadow}@keyframes chamshadow{0%,to{transform:scaleX(1)}50%{transform:scaleX(.92)}}.cham-eyes{translate:var(--eye-x) var(--eye-y);transition:translate .18s ease-out}.cham.look .cham-eyes{translate:-2.5px 1px}.cham.think .cham-eyes{translate:1.5px -2px}.cham.look .cham-body{rotate:-6deg}.cham-hand{transform-box:view-box;transition:translate .35s var(--spring);animation:3.2s ease-in-out infinite chamhand}.cham-hand.left{transform-origin:28px 26px}.cham-hand.right{transform-origin:28px 26px;animation:9s ease-in-out infinite chamwave}@keyframes chamhand{0%,to{transform:translateY(0)}50%{transform:translateY(-1.8px)}}@keyframes chamwave{0%,62%,to{transform:rotate(0)translateY(0)}31%{transform:rotate(0)translateY(-1.8px)}67%{transform:rotate(-42deg)}71%{transform:rotate(-58deg)}75%{transform:rotate(-36deg)}79%{transform:rotate(-58deg)}83%{transform:rotate(-36deg)}87%{transform:rotate(-42deg)}93%{transform:rotate(0)}}.cham.calm .cham-hand.right{animation-name:chamhand;animation-duration:3.2s}.hero-cham{cursor:pointer;touch-action:manipulation;-webkit-tap-highlight-color:transparent;width:96px}.greet .cham-hand.right{animation:1.7s ease-in-out .45s chamgreet,9s ease-in-out 2.2s infinite chamwave}@keyframes chamgreet{0%,to{transform:rotate(0)}18%{transform:rotate(-42deg)}32%{transform:rotate(-58deg)}46%{transform:rotate(-36deg)}60%{transform:rotate(-58deg)}74%{transform:rotate(-42deg)}}a:hover>.cham .cham-hand.right,.hero-cham:hover .cham-hand.right{animation:1.1s ease-in-out infinite chamgreet}.cham.joy .cham-hand.left{animation:.7s ease-in-out infinite alternate chamjoyl}.cham.joy .cham-hand.right{animation:.7s ease-in-out infinite alternate chamjoyr}@keyframes chamjoyl{0%{transform:rotate(36deg)}to{transform:rotate(58deg)}}@keyframes chamjoyr{0%{transform:rotate(-36deg)}to{transform:rotate(-58deg)}}.cham.look .cham-hand.left,.cham.think .cham-hand.right{animation:none}.cham.look .cham-hand.left{translate:11px 7px}.cham.think .cham-hand.right{translate:-8px 8px}.trail-cham{bottom:-7px}.walk-cham{margin-left:-23px;bottom:12px}.logocham{flex:none;display:block;overflow:visible}.mainnav{grid-template-columns:repeat(4,1fr)}.physhero{gap:18px;display:grid}.physhero h1{font:500 34px/1.2 var(--math);margin-bottom:8px}.physacts{gap:10px;margin-top:16px;display:grid}.physacts a{text-decoration:none}.physart{width:100%;max-width:420px}.heroflow{fill:none;stroke:#fff;stroke-width:4px;stroke-linecap:round;stroke-dasharray:1 19;animation:1s linear infinite flowrun}.glow{transform-box:fill-box;transform-origin:50%;animation:2.2s ease-in-out infinite glow}@keyframes glow{50%{transform:scale(1.08)}}.lablist{margin:0;padding:0;list-style:none;display:grid}.lablist a{min-height:60px;color:inherit;border-top:1px solid var(--line);align-items:center;gap:14px;padding:10px 0;text-decoration:none;display:flex}.lablist li:first-child a{border-top:0}.lablist a:hover b{color:var(--violet)}.lablist b{font-weight:500;display:block}.lablist small{color:var(--ink-2);font-size:14px}.labnum{background:var(--violet-soft);width:36px;height:36px;color:var(--violet);border-radius:50%;flex:none;place-items:center;font-weight:600;display:grid}.labnum.ok{background:var(--violet);color:var(--paper)}.symbols{grid-template-columns:repeat(3,1fr);gap:12px;margin:0;padding:0;list-style:none;display:grid}.symbols li{text-align:center;font-size:15px}.symbols svg{width:100%;max-width:110px}.syllabus{grid-template-columns:repeat(2,1fr);gap:20px;display:grid}.sylgrade ul{margin:6px 0 0;padding:0;font-size:16px;list-style:none}.sylgrade li{color:var(--ink-2);padding:5px 0}.sylgrade li small,.sylgrade li em{font-size:13.5px;font-style:normal;display:block}.sylgrade li.on{color:var(--ink);font-weight:500}.sylgrade li.on em{color:var(--violet)}.lab{gap:14px;display:grid}.lab-canvas{background:var(--surface);border:1.5px solid var(--line-2);touch-action:manipulation;border-radius:16px}.lab-canvas svg{-webkit-user-select:none;user-select:none;width:100%;height:auto;display:block}.edge{stroke:var(--line-2);stroke-width:2px;stroke-dasharray:3 7}.gridnode{fill:var(--line-2);pointer-events:none}.edgehit{fill:#0000;cursor:pointer}.edgehit:hover{fill:color-mix(in srgb, var(--violet) 12%, transparent)}.partin{animation:.22s ease-out backwards partin}@keyframes partin{0%{opacity:0}}.partwrap.picked{filter:drop-shadow(0 0 5px var(--violet))}.partwrap{pointer-events:none}.flowdots{fill:none;stroke:#fff;stroke-width:4px;stroke-linecap:round;stroke-dasharray:.01 20;animation:1s linear infinite flowrun}.flowdots.e{stroke:#ffe27a}@keyframes flowrun{to{stroke-dashoffset:-20px}}.flowarrow{fill:none;stroke:var(--ink);stroke-width:3px;stroke-linecap:round;stroke-linejoin:round;opacity:.75}.flowarrow.e{stroke:#b87a00}.lever{transition:d .2s var(--soft)}.lab-switches{grid-template-columns:1fr 1fr;gap:8px;margin-bottom:10px;display:grid}.miniseg{background:var(--line);border-radius:12px;grid-template-columns:1fr 1fr;gap:2px;padding:3px;display:grid}.miniseg button{min-height:40px;color:var(--ink-2);cursor:pointer;background:0 0;border:0;border-radius:9px;padding:0 4px;font-size:14.5px;font-weight:500}.miniseg button[aria-pressed=true]{background:var(--surface);color:var(--violet)}.legend{color:var(--ink-2);flex-wrap:wrap;gap:4px 14px;margin-top:8px;font-size:14px;display:flex}.legend i{vertical-align:-1px;border-radius:50%;width:12px;height:12px;margin-right:5px;display:inline-block}.legend .dotk{background:var(--ink);vertical-align:1px;width:8px;height:8px}.shortwarn{color:#8a1c1c;background:#ffe3e3;border-radius:12px;margin:8px 0 0;padding:10px 14px;font-size:16px}.toolbox{grid-template-columns:repeat(4,1fr);gap:8px;display:grid}.toolbox button{border:1.5px solid var(--line-2);background:var(--surface);min-height:72px;color:var(--ink);cursor:pointer;transition:transform .28s var(--spring), border-color .15s, background-color .15s;border-radius:12px;justify-items:center;gap:2px;padding:6px 2px;font-size:14px;font-weight:500;display:grid}.toolbox svg{width:62px;height:36px;overflow:visible}.toolbox button[aria-pressed=true]{border-color:var(--violet);background:var(--violet-soft);box-shadow:inset 0 0 0 1.5px var(--violet)}.toolbox button:active{transform:scale(.95)}.labhint{color:var(--ink-2);margin:10px 0;font-size:15px}.partpanel{background:var(--surface);border:1.5px solid var(--line-2);border-radius:14px;gap:10px;padding:14px;display:grid}.partread{font:500 20px var(--math);flex-wrap:wrap;gap:4px 16px;display:flex}.partacts{grid-auto-columns:1fr;grid-auto-flow:column;gap:8px;display:grid}.partacts .btn{width:100%;min-width:0;min-height:46px;padding:0 8px;font-size:16px}.labrun .labtitle{font:500 28px/1.2 var(--math);margin-bottom:14px}.goals{gap:6px;margin:0;padding:0;font-size:16px;list-style:none;display:grid}.goals li{color:var(--ink-2);align-items:center;gap:10px;display:flex}.goals i{border:2px solid var(--line-2);border-radius:50%;flex:none;place-items:center;width:24px;height:24px;font-size:14px;font-style:normal;font-weight:700;display:grid}.goals li.ok{color:var(--ink)}.goals li.ok i{background:var(--good);border-color:var(--good);color:var(--paper);animation:pop .32s var(--spring)}.labfoot{gap:10px;margin-top:8px;display:grid}.labfoot .btn{width:100%;text-decoration:none}.recordbox{gap:8px;display:grid}.recordbox table{font-variant-numeric:tabular-nums}.labnarrow{max-width:620px}a.btn{text-decoration:none}@media (width>=860px){.physhero{grid-template-columns:1.1fr 1fr;align-items:center;gap:48px}.physhero h1{font-size:46px}.physacts{display:flex}.lablist{grid-template-columns:1fr 1fr;grid-auto-flow:row;column-gap:40px}.lablist li:nth-child(2) a{border-top:0}.symbols{grid-template-columns:repeat(6,1fr)}.syllabus{grid-template-columns:repeat(4,1fr)}.lab{grid-template-columns:minmax(0,1.55fr) minmax(280px,1fr);align-items:start;gap:28px}.toolbox{grid-template-columns:repeat(3,1fr)}.labfoot{grid-auto-flow:column;justify-content:start}.labfoot .btn{width:auto}.labrun .labnarrow{width:100%;margin-inline:auto}}@media (prefers-reduced-motion:reduce){.flowdots,.heroflow{stroke-dasharray:none;opacity:0}}.partlabel{fill:var(--ink);paint-order:stroke;stroke:var(--surface);stroke-width:4px;stroke-linejoin:round;pointer-events:none;font-size:14px;font-weight:600}.sim{gap:14px;display:grid}.simart{background:var(--surface);border:1.5px solid var(--line-2);border-radius:16px;padding:10px;overflow:hidden}.simart svg{width:100%;height:auto;max-height:340px;display:block}.simctl{align-content:start;gap:12px;display:grid}.simsl b{color:var(--ink);font-weight:600}.simchips{flex-wrap:wrap;gap:8px;display:flex}.simchips button{border:1.5px solid var(--line-2);background:var(--surface);cursor:pointer;min-height:44px;transition:transform .28s var(--spring), background-color .15s, border-color .15s;border-radius:12px;padding:0 14px;font-size:15.5px;font-weight:500}.simchips button[aria-pressed=true]{background:var(--violet);border-color:var(--violet);color:var(--paper)}.simread{font:400 19px/1.45 var(--math);background:var(--violet-soft);border-radius:12px;padding:10px 14px}.realtask{border:1.5px solid var(--line-2);background:var(--surface);border-radius:14px;padding:14px 16px}.realtask b{color:var(--violet);margin-bottom:4px;font-weight:600;display:block}.hookq{font:500 20px/1.4 var(--math);margin-bottom:10px}.quizq{margin-bottom:8px}.opt.rightopt{border-color:var(--good)}.loadpreset{width:100%}@media (width>=860px){.sim{grid-template-columns:1.4fr 1fr;align-items:start;gap:28px}.loadpreset{width:auto}.labfoot .link{align-self:center}}.modelnote{color:var(--ink-2);border-left:3px solid var(--line-2);margin-top:10px;padding-left:10px;font-size:14.5px}.retry{background:var(--mark-soft);border-radius:14px;padding:14px}.answertag{color:var(--good);white-space:nowrap;margin-left:auto;padding-left:10px;font-size:14px;font-style:normal;font-weight:600}.reviewbanner{background:var(--violet-soft);color:var(--ink);border-radius:12px;margin-bottom:10px;padding:10px 14px;font-size:15.5px}.reviewing .opt:not(:disabled){pointer-events:none}.reviewbar{padding:10px 0 max(10px, env(safe-area-inset-bottom));background:var(--paper);border-top:1px solid var(--line);gap:8px;margin-top:18px;display:grid;position:sticky;bottom:0}.reviewnav{grid-template-columns:1fr 1fr;gap:10px;display:grid}.reviewnav .btn{width:100%;min-width:0;padding:0 8px}.notebox>summary{cursor:pointer;min-height:44px;color:var(--violet);align-items:center;font-weight:500;display:flex}.notebox[open]>:not(summary){margin-bottom:8px}textarea.notearea{font-family:var(--ui);width:100%;font-size:16px}.critrow{border-top:1px solid var(--line);gap:6px;padding:8px 0;display:grid}.miniseg.tri{grid-template-columns:repeat(3,1fr)}@media (width>=860px){.critrow{grid-template-columns:1fr 300px;align-items:center}.reviewnav{justify-content:flex-end;display:flex}.reviewnav .btn{width:auto;min-width:170px}}.reviewbar{position:static}.stage{--ink:#22212e;--ink-2:#55536a;--surface:#fff;--line:#e2dfec;--violet-soft:#e3f1fa;--violet-2:#9ccbe9;--violet:var(--ly-stage);touch-action:none;-webkit-user-select:none;user-select:none;cursor:grab;background:var(--surface);width:100%;max-width:540px;height:auto;box-shadow:inset 0 0 0 1.5px var(--line-2);border-radius:16px;margin:0 auto;display:block}.stage:active{cursor:grabbing}.playsay{font:500 18px/1.45 var(--ui);background:var(--violet-soft);margin-top:12px;border-radius:12px;max-width:540px;margin-inline:auto;padding:12px 14px}.playrow{margin-top:12px;flex-wrap:wrap;justify-content:space-between;align-items:center;gap:10px;max-width:540px;margin-inline:auto;display:flex}.playrow .btn{width:auto;min-width:0;min-height:44px;padding:0 14px;font-size:15.5px}[data-screen=lab] .stage+.simchips,[data-screen=lab] .stage~.btn{margin-top:12px;max-width:540px;margin-inline:auto}[data-screen=lab] .stage~.simchips{justify-content:center;margin-top:12px}[data-screen=lab] .stage~.btn{display:flex}.photons{stroke-dasharray:.01 16;animation:.6s linear infinite flowrun}.handhint{animation:1.4s ease-in-out infinite handhint}@keyframes handhint{50%{opacity:.55;transform:scale(1.25)}}.starhit{animation:starhit .6s var(--spring);transform-box:fill-box;transform-origin:50%}@keyframes starhit{0%{scale:.6}}.nudge{animation:nudge .35s var(--spring)}@keyframes nudge{0%{transform:translate(10px)}}.racebars{margin-top:12px;gap:6px;max-width:540px;margin-inline:auto;font-size:15px;display:grid}.racebars>div{grid-template-columns:90px 1fr 60px;align-items:center;gap:8px;display:grid}.racebars i{background:var(--violet);border-radius:3px;height:14px;transition:width .3s;display:block}.racebars b{text-align:right;font-weight:500}.benchbox{border:1.5px solid var(--violet);background:var(--surface);border-radius:14px;padding:4px 14px 14px}.benchhead{cursor:pointer;text-align:left;width:100%;min-height:52px;color:var(--violet);background:0 0;border:0;justify-content:space-between;align-items:center;gap:12px;display:flex}.benchhead b{font-weight:600}.benchhead span{flex:none;font-size:14px}.benchneed{flex-wrap:wrap;gap:6px;margin:0;padding:0;list-style:none;display:flex}.benchneed li{background:var(--mark-soft);border-radius:16px;padding:4px 10px;font-size:15px}.benchsteps{gap:4px;margin:0;padding:0;list-style:none;display:grid}.benchsteps label{cursor:pointer;align-items:flex-start;gap:10px;min-height:44px;padding:6px 0;display:flex}.benchsteps input{width:22px;height:22px;accent-color:var(--violet);flex:none;margin-top:2px}.benchinput{border:1.5px solid var(--line-2);background:var(--paper);border-radius:8px;width:100%;min-width:70px;min-height:44px;padding:0 8px}.fx{gap:10px;display:grid}.fxlines{gap:2px;padding:6px 0;animation:none;display:grid}.fxline{flex-wrap:wrap;justify-content:center;align-items:center;gap:0 3px;display:flex}.fxsym{font:inherit;color:var(--violet);cursor:pointer;text-underline-offset:6px;min-width:36px;min-height:44px;transition:background .15s, transform .2s var(--spring);background:0 0;border:0;border-radius:9px;padding:0 5px;-webkit-text-decoration:underline dotted;text-decoration:underline dotted;text-decoration-thickness:2px}.fxsym.op{color:var(--ink);min-width:28px;padding:0 2px;text-decoration:none}.fxsym:hover,.fxsym:focus-visible{background:var(--violet-soft)}.fxsym.on{background:var(--mark);color:#22212e;text-decoration:none;transform:translateY(-2px)scale(1.08)}.fxcard{background:var(--violet-soft);animation:fxin .22s var(--soft);border-radius:14px;align-content:center;gap:6px;min-height:84px;padding:14px 16px;display:grid}.fxcard p{margin:0}@keyframes fxin{0%{opacity:0;transform:translateY(5px)}}.fxcardhead{align-items:center;gap:10px;font-size:19px;display:flex}.fxkey{text-align:center;background:var(--mark);color:#22212e;min-width:38px;font:500 21px/1.4 var(--math);border-radius:8px;flex:none;padding:1px 8px}.fxmeta{font-size:15.5px}.fxmeta span{min-width:50px;color:var(--ink-2);display:inline-block}.fxhint{color:var(--violet);font-size:15px;font-weight:600}.fxread{color:var(--ink-2);text-align:center;margin:0;font-size:15.5px}.fxall{font-size:15px}.fxall summary{cursor:pointer;min-height:40px;color:var(--ink-2)}.fxall dl{gap:8px;margin:0;display:grid}.fxall dl>div{grid-template-columns:48px 1fr;gap:8px;display:grid}.fxall dt{font:500 18px var(--math)}.fxall dd{margin:0}.fxsym.sup{min-width:24px;margin-left:-9px;padding:0 2px}.termw{font:inherit;color:var(--violet);cursor:pointer;text-underline-offset:4px;background:0 0;border:0;border-radius:4px;margin:0;padding:0;font-weight:600;-webkit-text-decoration:underline dotted;text-decoration:underline dotted;text-decoration-thickness:1.5px;transition:background .15s;display:inline;position:relative}.termw:after{content:"";position:absolute;inset:-8px -2px}.termw:hover{background:var(--violet-soft)}.opt .termw{pointer-events:none}.termlayer{z-index:60;background:#14122847;animation:.15s fadeterm;position:fixed;inset:0}@keyframes fadeterm{0%{opacity:0}}.termsheet{background:var(--surface,var(--paper));padding:14px 18px calc(18px + env(safe-area-inset-bottom));animation:sheetup .24s var(--soft);border-radius:18px 18px 0 0;outline:0;gap:10px;max-height:75vh;display:grid;position:absolute;bottom:0;left:0;right:0;overflow:auto;box-shadow:0 -10px 34px #14122838}@keyframes sheetup{0%{opacity:0;transform:translateY(40px)}}.termsheet.pop{border-radius:14px;width:380px;padding-bottom:16px;right:auto;box-shadow:0 10px 34px #14122840}.termlayer:has(.pop){background:0 0}.termtop{align-items:center;gap:6px;display:flex}.termtop h2{font:600 25px/1.2 var(--math);color:var(--violet);flex:1;margin:0}.termtop h2:first-letter{text-transform:uppercase}.termx,.termback{width:44px;height:44px;color:var(--ink-2);cursor:pointer;background:0 0;border:0;border-radius:10px;flex:none;font-size:28px;line-height:1}.termx:hover,.termback:hover{background:var(--violet-soft)}.termback{margin-left:-12px}.termdef{margin:0;font-size:18.5px;line-height:1.45}.termeg,.termno{margin:0;font-size:16px;line-height:1.45}.termeg span,.termno span{color:var(--ink-2);font-size:13.5px;font-weight:600;display:block}.termno{background:var(--mark-soft);border-radius:10px;padding:8px 12px}.termlink{min-height:44px;color:var(--violet);align-items:center;font-size:15.5px;font-weight:500;display:flex}.termsearch{border:1.5px solid var(--line-2);background:var(--paper);width:100%;max-width:480px;min-height:48px;color:var(--ink);font:inherit;border-radius:12px;margin:14px 0;padding:0 14px}.termgrid{grid-template-columns:repeat(auto-fill,minmax(min(100%,300px),1fr));gap:12px;display:grid}.termcard{background:var(--surface,var(--paper));box-shadow:inset 0 0 0 1.5px var(--line-2);border-radius:14px;align-content:start;gap:8px;padding:14px 16px;display:grid}.termcard h2{font:600 20px/1.2 var(--math);color:var(--violet);margin:0}.termcard h2:first-letter{text-transform:uppercase}.termcard .termdef{font-size:16.5px}.termsheet.pop{box-shadow:0 0 0 1.5px var(--line-2), 0 10px 34px #1412284d}:root{--toan:#4b2fc9;--toan-soft:#efecfd;--ly:#0a6aa8;--ly-soft:#e4f2fb;--ly-stage:#0a6aa8;--paper:#fbfaf8;--ink:#22202c;--ink-2:#55526a}@media (prefers-color-scheme:dark){:root:not([data-theme=light]){--toan:#a594ff;--toan-soft:#2a2547;--ly:#70c2f3;--ly-soft:#14303f;--paper:#15131f;--ink:#eceaf5;--ink-2:#a9a5bd}}:root[data-theme=dark]{--toan:#a594ff;--toan-soft:#2a2547;--ly:#70c2f3;--ly-soft:#14303f;--paper:#15131f;--ink:#eceaf5;--ink-2:#a9a5bd}:root[data-subject=physics]{--violet:var(--ly);--violet-soft:var(--ly-soft);--violet-2:#6db4e0}body{font:400 17.5px/1.62 var(--ui);font-feature-settings:"tnum" 0;-webkit-font-smoothing:antialiased;text-rendering:optimizelegibility}h1,h2,h3{line-height:1.32}.hook,.prompt{font:400 20px/1.62 var(--ui)}.hookq{font:500 19px/1.5 var(--ui)}.opt{font-size:18px;line-height:1.45}.pagetitle{font:600 clamp(26px, 3vw, 34px)/1.3 var(--ui);letter-spacing:-.01em;margin-bottom:14px}.labrun .labtitle{font:600 clamp(23px, 2.6vw, 30px)/1.32 var(--ui);letter-spacing:-.008em;margin-bottom:14px}.bigok{font:600 28px/1.3 var(--ui)}.formula,.fxsym,.fxkey,.frac,.num,.fxall dt,.glimpse{font-family:var(--sym)}.fact b{font-family:var(--ui);font-size:30px;font-weight:600}.smallhead{font:600 15.5px var(--ui)}.btn{border-radius:12px;font-weight:600}.opt,.grades button{border-radius:12px}.textlink{color:var(--violet)}.appbar{background:color-mix(in srgb, var(--paper) 94%, transparent);-webkit-backdrop-filter:none;backdrop-filter:none;border-bottom:1px solid var(--line)}.appbar-in{gap:12px;max-width:1200px;min-height:62px;padding:6px 16px}.brandmark{color:var(--ink);letter-spacing:-.01em;gap:6px;font-size:18px;font-weight:700;text-decoration:none}.subnav{background:var(--paper);border-bottom:1px solid var(--line)}.subnav-in{scrollbar-width:none;gap:22px;max-width:1200px;margin:0 auto;padding:0 16px;display:flex;overflow-x:auto}.subnav a{min-height:46px;color:var(--ink-2);white-space:nowrap;align-items:center;font-size:16px;font-weight:500;text-decoration:none;transition:color .15s,box-shadow .2s;display:flex;box-shadow:inset 0 0 #0000}.subnav a:hover{color:var(--violet)}.subnav a[aria-current=page]{color:var(--violet);box-shadow:inset 0 -3px 0 var(--violet);font-weight:600}.mainnav{padding-bottom:env(safe-area-inset-bottom);grid-template-columns:repeat(3,1fr)}.navitem[aria-current=page]{color:var(--violet)}.navitem[aria-current=page] svg{fill:none}.nav-math[aria-current=page],.nav-math:hover{color:var(--toan)}.nav-physics[aria-current=page],.nav-physics:hover{color:var(--ly)}.suggest em{font:600 12px/1.5 var(--ui);vertical-align:2px;border-radius:6px;margin-left:8px;padding:1px 7px}.tagm{background:var(--toan-soft);color:var(--toan)}.tagp{background:var(--ly-soft);color:var(--ly)}.suggest b:first-letter{text-transform:uppercase}.suggest small{-webkit-line-clamp:2;-webkit-box-orient:vertical;display:-webkit-box;overflow:hidden}@media (width>=860px){.appbar-in{gap:8px;min-height:66px;padding:6px 24px}.brandmark span{display:inline}.brandmark{margin-right:18px}.mainnav{display:contents}.navitem{min-height:44px;color:var(--ink-2);border-radius:22px;order:2;align-items:center;gap:8px;padding:0 16px 0 12px;font-size:16px;font-weight:500;text-decoration:none;transition:background-color .15s,color .15s;display:flex}.navitem svg{fill:none;stroke:currentColor;stroke-width:2px;stroke-linecap:round;stroke-linejoin:round;width:20px;height:20px}.nav-math:hover,.nav-math[aria-current=page]{background:var(--toan-soft)}.nav-physics:hover,.nav-physics[aria-current=page]{background:var(--ly-soft)}.navitem[aria-current=page]{font-weight:600}.searchbar{border-radius:22px;flex:200px;order:3;max-width:460px;min-height:44px;margin-inline:auto 12px}.searchbar input{height:40px}.nav-me{order:4}.nav-me:hover,.nav-me[aria-current=page]{background:var(--line);color:var(--ink)}.subnav-in{gap:28px;padding:0 24px}}.choosepage{flex-direction:column;min-height:100vh;display:flex}.choosetop{padding:8px 16px}.choosetop .brandmark span{display:inline}.choosemain{flex:1;align-content:start;gap:20px;width:100%;max-width:920px;margin:0 auto;padding:8px 16px 40px;display:grid}.choosemain h1{font:600 clamp(27px, 4vw, 42px)/1.28 var(--ui);letter-spacing:-.012em}.subjectgrid{gap:14px;display:grid}.subjectcard{color:var(--ink);transition:transform .25s var(--spring), box-shadow .2s;border-radius:22px;gap:12px;padding:22px;text-decoration:none;display:grid;position:relative}.subjectcard.math{--c:var(--toan);background:var(--toan-soft)}.subjectcard.physics{--c:var(--ly);background:var(--ly-soft)}.subjectcard:hover{box-shadow:0 0 0 2px var(--c);transform:translateY(-3px)}.subjectcard:active{transform:scale(.985)}.subjectart{color:var(--c);max-width:210px;display:block}.subjectart svg{width:100%;height:auto;display:block}.subjectbody{gap:4px;display:grid}.subjectbody b{color:var(--c);font-size:28px;font-weight:700;line-height:1.25}.subjectbody small{color:var(--ink-2);font-size:15px}.subjectcard em{background:var(--c);color:var(--paper);font:600 13.5px/1.6 var(--ui);border-radius:14px;padding:3px 11px;position:absolute;top:16px;right:16px}@media (width>=720px){.subjectgrid{grid-template-columns:1fr 1fr;gap:20px}.subjectcard{align-content:start;gap:20px;padding:32px}.choosemain{gap:28px;padding-top:5vh}.choosetop{padding:8px 24px}}.homehead{flex-wrap:wrap;justify-content:space-between;align-items:center;gap:6px 16px;margin-bottom:14px;display:flex}.homehead .pagetitle{margin:0}.homehead .grades{gap:4px;margin:0}.homehead .grades button{flex:none;width:46px;min-height:44px;font-weight:600}.contcard{background:var(--violet-soft);border-radius:20px;gap:18px;padding:20px;display:grid}.contbody{justify-items:start;gap:6px;display:grid}.contbody h2{font-size:clamp(22px,2.6vw,30px);font-weight:600}.contbody .btn{width:auto;min-width:180px;margin-top:10px;text-decoration:none}.eyebrow{color:var(--violet);font-size:15px;font-weight:600}.contside{grid-template-columns:auto 1fr;align-items:baseline;gap:2px 10px;display:grid}.contside b{font-size:26px;font-weight:700}.contside small{color:var(--ink-2);font-size:16px;font-weight:500}.contside span{color:var(--ink-2);font-size:15px}.contside .progress{grid-column:1/-1;margin-top:6px}.progress{background:var(--line)}.contcard .progress{background:color-mix(in srgb, var(--violet) 18%, transparent)}.savehint{margin-top:10px}.chapgrid{gap:14px;margin-top:18px;display:grid}.chapcard{background:var(--surface);box-shadow:inset 0 0 0 1.5px var(--line);border-radius:18px;min-width:0;padding:16px 18px 8px}.chapcard header{justify-content:space-between;align-items:baseline;gap:12px;margin-bottom:8px;display:flex}.chapcard h2{font-size:18px;font-weight:600}.chapcard header span{color:var(--ink-2);font-variant-numeric:tabular-nums;flex:none;font-size:15px}.chapcard .lablist{margin-top:6px;grid-template-columns:1fr!important}.chapcard .lablist a{min-height:56px;padding:8px 0}.chapcard .lablist li:nth-child(2) a{border-top:1px solid var(--line)}.isnext b{color:var(--violet);font-weight:600}.isnext .labnum{background:var(--violet);color:var(--paper)}.teacherlink{margin-top:26px;font-size:15px}@media (width>=860px){.contcard{grid-template-columns:1fr 260px;align-items:center;padding:28px 32px}.chapgrid{grid-template-columns:1fr 1fr;align-items:start;gap:18px}.wrap.roomy{padding-top:32px}}.labrun{max-width:1120px}.labrun>.top{gap:14px;margin-bottom:18px}.progresslabel{clip-path:inset(50%);width:1px;height:1px;position:absolute;overflow:hidden}.stepper{flex:1;gap:5px;min-width:0;max-width:560px;margin:0;padding:0;list-style:none;display:flex}.stepper li{min-width:0;color:var(--ink-2);flex:1;gap:4px;font-size:13.5px;display:grid}.stepper i{background:var(--line);border-radius:3px;height:6px;transition:background-color .3s;display:block}.stepper .done i,.stepper .now i{background:var(--violet)}.stepper span{white-space:nowrap;visibility:hidden;height:0;overflow:hidden}.stepper .now span{visibility:visible;height:auto;color:var(--violet);font-weight:600;overflow:visible}.labrun .stagename{font-size:14.5px}.labnarrow{width:100%;max-width:660px;margin-inline:auto}.labrun .hook{font-size:20px}.goals{font-size:16.5px;line-height:1.45}@media (width<=859px){.labfoot{z-index:5;padding:12px 0 max(12px, env(safe-area-inset-bottom));background:linear-gradient(transparent, var(--paper) 14px);margin-bottom:-12px;position:sticky;bottom:0}.labrun{padding-bottom:28px}}.tryarea>*+*{margin-top:14px}@media (width>=1000px){.stepper span{visibility:visible;height:auto;overflow:visible}.labrun .hook{font-size:21px}.tryarea:has(.stage){grid-template-columns:minmax(0,1.4fr) minmax(300px,1fr);align-items:start;gap:12px 36px;display:grid}.tryarea:has(.stage)>*{grid-column:2;margin:0}.tryarea:has(.stage)>.trybox{display:contents}.tryarea:has(.stage) .stage{grid-area:1/1/span 12;max-width:none;position:sticky;top:16px}.tryarea:has(.stage) .trybox>*{grid-column:2;max-width:none;margin:0}.tryarea:has(.stage) .playrow{justify-content:flex-start}.tryarea:has(.stage) .simchips{justify-content:flex-start}.tryarea:has(.stage) .trybox>.stage{grid-column:1}}.profilehead{justify-content:flex-start;align-items:center;gap:12px;margin-bottom:16px;display:flex}.profilehead .pagetitle{margin:0;line-height:1.2}.segment.four{grid-template-columns:repeat(4,1fr);max-width:560px}.segment.four button{padding:0 2px;font-size:15.5px}.subjgrid{gap:14px;display:grid}.subjcard{border-radius:20px;gap:8px;padding:18px 20px 20px;display:grid}.subjcard.math{background:var(--toan-soft);--violet:var(--toan)}.subjcard.physics{background:var(--ly-soft);--violet:var(--ly)}.subjcard header{justify-content:space-between;align-items:center;gap:12px;display:flex}.subjcard h2{color:var(--violet);font-size:23px;font-weight:700}.subjcard .link{color:var(--violet);min-height:44px;padding:0}.subjnum{color:var(--ink-2)}.subjnum b{color:var(--ink);font-size:28px;font-weight:700}.subjcard .btn{background:var(--violet);border-color:var(--violet);width:100%;margin-top:8px;text-decoration:none}.subjcard .progress{background:color-mix(in srgb, var(--violet) 20%, transparent)}.subjcard .progress i{background:var(--violet)}.activity-bars.both{align-items:flex-end}.activity-bars.both>span{flex-direction:column;flex:1;justify-content:flex-end;gap:1px;min-width:0;height:100%;display:flex}.activity-bars.both i{border-radius:2px;width:100%;display:block}.activity-bars.both i.m{background:var(--toan)}.activity-bars.both i.p{background:var(--ly)}.legend{color:var(--ink-2);gap:16px;margin-top:6px;font-size:14.5px;display:flex}.legend span:before{content:"";border-radius:3px;width:11px;height:11px;margin-right:6px;display:inline-block}.legend .m:before{background:var(--toan)}.legend .p:before{background:var(--ly)}.recent a{text-decoration:none}@media (width>=720px){.subjgrid{grid-template-columns:1fr 1fr;gap:18px}}.progress{border-radius:3px;height:6px}.progress>i{border-radius:3px}@media (width>=1000px){.labnarrow{margin-inline:0}.labfoot{justify-content:start}}.benchbox{padding-bottom:4px}.benchbox:has(.stack){padding-bottom:14px}@media (width>=720px){.choosemain{align-content:center;padding-top:0;padding-bottom:12vh}.subjectart{max-width:280px}.subjectcard{padding:36px}}h1,.lbig{text-wrap:balance}.lhero-text{flex-basis:480px}.subjgrid+.statrow{margin-top:22px}@media (width<=859px){.labfoot:has(.btn:disabled){background:0 0;margin-bottom:0;padding-bottom:12px;position:static}}.wordmark{color:var(--brand);display:block;overflow:visible}:root{--brand:#2e1c9e}@media (prefers-color-scheme:dark){:root:not([data-theme=light]){--brand:#f4f2ff}}:root[data-theme=dark]{--brand:#f4f2ff}a:hover>.wordmark .wm-dot{animation:wmhop .62s var(--spring)}.wordmark.drop .wm-dot{animation:1s cubic-bezier(.3,0,.3,1) .35s backwards wmdrop}@keyframes wmhop{0%{transform:none}22%{transform:scale(1.14,.84)}55%{transform:translateY(-16%)scale(.94,1.08)}80%{transform:scale(1.08,.92)}to{transform:none}}@keyframes wmlive{0%,90%,to{transform:none}92%{transform:scale(1.12,.86)}95%{transform:translateY(-22%)scale(.95,1.06)}98%{transform:scale(1.06,.94)}}@keyframes wmdrop{0%{opacity:0;transform:translateY(-900%)}10%{opacity:1}62%{transform:translateY(0)scale(1)}72%{transform:scale(1.3,.68)}84%{transform:translateY(-40%)scale(.92,1.1)}94%{transform:scale(1.1,.9)}to{transform:none}}.brandmark{min-height:48px;color:inherit;align-items:center;margin-right:8px}.brandmark span{display:none!important}.factcard{background:var(--mark-soft);border-radius:20px;justify-items:start;gap:10px;margin-top:16px;padding:18px 20px 20px;display:grid}.facthead{align-items:center;gap:8px;display:flex}.factcard .eyebrow{color:var(--warn-ink);margin:0}.factcard h2{text-wrap:balance;font-size:clamp(21px,2.6vw,28px);font-weight:600;line-height:1.34}.factanswer{font-size:18.5px;line-height:1.66}.facttry{background:var(--violet-soft);border-radius:12px;padding:10px 14px;line-height:1.5}.facttry b{color:var(--violet);font-size:14px;display:block}.factcard .btn{border-color:var(--warn-ink);color:var(--warn-ink)}.factcard .btn:hover{background:color-mix(in srgb, var(--warn-ink) 10%, transparent)}.factlinks{flex-wrap:wrap;gap:4px 20px;display:flex}.factlinks a,.factnav a{align-items:center;min-height:44px;display:inline-flex}.btn.fit{justify-self:start;width:auto;text-decoration:none}.reading{max-width:700px!important}.crumbs{margin-bottom:8px;font-size:15px}.crumbs a{min-height:40px;color:var(--ink-2);align-items:center;display:inline-flex}.crumbs a:before{content:"‹";margin-right:6px;font-size:19px}.capfirst:first-letter,.termcard h2 a:first-letter{text-transform:uppercase}.chipslist{flex-wrap:wrap;gap:8px;margin:8px 0 0;padding:0;list-style:none;display:flex}.chipslist a{background:var(--violet-soft);min-height:42px;color:var(--violet);border-radius:21px;align-items:center;padding:0 14px;font-weight:500;text-decoration:none;display:inline-flex}.factnav{border-top:1px solid var(--line);justify-content:space-between;padding-top:6px;display:flex}.factlist{margin:18px 0 0;padding:0;list-style:none}.factlist a{border-top:1px solid var(--line);color:inherit;padding:14px 0;font-size:18px;font-weight:500;line-height:1.45;text-decoration:none;display:block}.factlist a:hover{color:var(--violet)}.factlist em{background:var(--mark);color:var(--on-mark);font:600 13px/1.6 var(--ui);vertical-align:2px;border-radius:12px;margin-right:10px;padding:1px 9px;display:inline-block}.termcard h2 a{color:inherit;text-decoration:none;display:inline-block}.termcard h2 a:hover{text-decoration:underline}.termlinks{flex-wrap:wrap;gap:0 18px;display:flex}.prerender{max-width:700px;margin:0 auto;padding:32px 20px}.prerender h1{margin-bottom:14px;font-size:30px}.prerender p,.prerender li{margin-bottom:8px}@media (width>=860px){.contcard+.factcard{margin-top:18px;padding:24px 32px}.reading{padding-top:36px}}.stack>.termeg,.stack>.termno{margin-top:12px}.lcircuit{gap:12px;display:grid}.lcircuit svg{width:100%;height:auto;display:block;overflow:visible}.lcmode{grid-template-columns:1fr 1fr;justify-self:start;width:220px;margin:0}.lcmode button{min-height:40px;font-size:15px}.lcmode button[aria-pressed=true]{background:var(--surface);color:var(--violet)}.lcin{animation:lcin .42s var(--spring)}@keyframes lcin{0%{opacity:0;transform:translateY(-14px)scale(.92)}}.lcflow{stroke:#ffc21a;stroke-width:4.5px;stroke-linecap:round;stroke-dasharray:.1 18;animation:.8s linear infinite lcrun}@keyframes lcrun{to{stroke-dashoffset:-18.1px}}.artflow{fill:none;stroke:#ffc21a;stroke-width:4px;stroke-linecap:round;stroke-dasharray:.1 16;animation:.8s linear infinite lcartrun}@keyframes lcartrun{to{stroke-dashoffset:-16.1px}}.lchit{cursor:pointer;outline-offset:-4px}.lctray{grid-template-columns:repeat(2,1fr);gap:8px;display:grid}.lctray button{border:1.5px solid var(--violet);background:var(--violet);min-height:46px;color:var(--paper);cursor:pointer;transition:background-color .15s, color .15s, transform .2s var(--spring);border-radius:12px;padding:0 8px;font-size:15.5px;font-weight:600}.lctray button[aria-pressed=true]{color:var(--violet);background:0 0}.lctray button:active{transform:scale(.96)}@media (width>=560px){.lctray{grid-template-columns:repeat(4,1fr)}}.lcircuit .playsay{max-width:none;margin:0;font-size:16.5px}.lctray{grid-template-columns:repeat(2,1fr)!important}@media (prefers-color-scheme:dark){:root:not([data-theme=light]) svg rect[fill=\#2B2A36]{stroke:var(--line-2);stroke-width:1.5px}}:root[data-theme=dark] svg rect[fill=\#2B2A36]{stroke:var(--line-2);stroke-width:1.5px}.elab{grid-template-columns:minmax(0,1fr);gap:8px;min-height:100dvh;padding:8px 10px 20px;display:grid}.elab.boom{animation:.5s elabshake}@keyframes elabshake{15%{transform:translate(-5px,3px)}35%{transform:translate(5px,-4px)}55%{transform:translate(-3px,-2px)}75%{transform:translate(3px,2px)}}.elabtop{flex-wrap:wrap;align-items:center;gap:8px 10px;display:flex}.elabtop h1{flex:auto;margin:0;font-size:19px;font-weight:700}.elabclock{font-variant-numeric:tabular-nums;justify-items:end;line-height:1.2;display:grid}.elabclock b{font-size:21px}.elabclock span{color:var(--ink-2);font-size:12px}.elabtopacts{flex-wrap:wrap;gap:6px;display:flex}.elabtopacts .btn{width:auto;min-height:44px;padding:0 12px;font-size:14.5px}.miniseg{flex:none}.elabtools{scrollbar-width:thin;order:3;gap:12px;min-width:0;padding-bottom:4px;display:flex;overflow-x:auto}.elabtools section{flex:none}.elabtools h2{color:var(--ink-2);white-space:nowrap;margin:0 0 4px;font-size:12.5px;font-weight:600}.elabgrid{gap:5px;display:flex}.elabgrid button{border:1.5px solid var(--line-2);background:var(--surface);cursor:pointer;border-radius:10px;align-content:center;justify-items:center;width:72px;min-height:62px;padding:2px;font-size:12.5px;line-height:1.2;display:grid}.elabgrid svg{pointer-events:none;--wire-a:#8a86a0;width:56px;height:34px}.elabgrid button[aria-pressed=true],.elabmodes button[aria-pressed=true]{border-color:var(--violet);background:var(--violet-soft);color:var(--violet);font-weight:600}.elabmodes{flex:none;align-content:end;gap:5px;display:grid}.elabmodes button{border:1.5px solid var(--line-2);background:var(--surface);cursor:pointer;border-radius:10px;min-width:62px;min-height:44px;font-size:14px}.elabmain{order:2;grid-template-rows:auto minmax(0,1fr);gap:6px;min-width:0;display:grid}.elabbar{flex-wrap:wrap;justify-content:space-between;align-items:center;gap:6px 10px;display:flex}.elabhint{color:var(--ink-2);flex:100%;order:3;font-size:14.5px}.elabscroll{background:var(--surface);box-shadow:inset 0 0 0 1.5px var(--line-2);border-radius:14px;max-height:62dvh;overflow:auto}.elabboard{width:calc(max(100%, 640px) * var(--zoom,1));touch-action:pan-x pan-y pinch-zoom;-webkit-user-select:none;user-select:none;cursor:crosshair;height:auto;display:block}.elabline{stroke:var(--line);stroke-width:1.5px}.elabpart.picked>.partin{filter:drop-shadow(0 0 5px var(--violet))}.elabpart.isdead>.partin{filter:grayscale()brightness(.62)}.elabpart.isburst>.partin{opacity:.55}.elabflame{transform-origin:0 6px;animation:.28s ease-in-out infinite alternate elabflame}@keyframes elabflame{0%{transform:scaleX(.92)}to{transform:scale(1.1,1.14)}}.elabsmoke circle{animation:1.5s ease-out infinite elabsmoke}@keyframes elabsmoke{0%{opacity:.75;transform:translateY(0)scale(.6)}to{opacity:0;transform:translateY(-34px)scale(1.5)}}.elabburst{transform-origin:0 0;animation:.6s ease-out both elabburst}@keyframes elabburst{0%{opacity:1;transform:scale(.2)}60%{opacity:1;transform:scale(1.5)}to{opacity:.5;transform:scale(1)}}.elabwave{animation:.4s ease-in-out infinite glow}@keyframes elabspin{to{transform:rotate(360deg)}}.elabside{order:4;align-content:start;gap:10px;min-width:0;display:grid}.elabnow{background:var(--violet-soft);border-radius:14px;padding:12px 14px}.elabnow h2{color:var(--ink-2);margin:0 0 4px;font-size:13.5px;font-weight:600}.elabnow p{margin:0;line-height:1.5}.elabnow.danger{color:#5a1b10;background:#fde8e4}.elabnow.warn{background:var(--mark-soft)}.elabnow.ok{background:color-mix(in srgb, var(--good) 14%, transparent)}.elabnow.danger .termw,.elabnow.danger h2{color:inherit}.elabfix{font-weight:500;margin-top:6px!important}.elabask{border-left:4px solid var(--mark);background:var(--mark-soft);border-radius:0 10px 10px 0;margin:0;padding:10px 14px;font-size:15.5px}.elabinspect{background:var(--surface);box-shadow:inset 0 0 0 1.5px var(--line);border-radius:14px;gap:10px;padding:10px 14px 14px;display:grid}.elabinspect header{justify-content:space-between;align-items:center;display:flex}.elabinspect h2{margin:0;font-size:18px;font-weight:600}.elabstats{grid-template-columns:1fr 1fr;gap:6px 12px;margin:0;display:grid}.elabstats dt{color:var(--ink-2);font-size:12.5px;line-height:1.3}.elabstats dd{font-variant-numeric:tabular-nums;margin:0;font-weight:600}.elabopt{gap:5px;font-size:14.5px;display:grid}.elabopt input{width:100%;min-height:40px;accent-color:var(--violet)}.elabchips{flex-wrap:wrap;gap:6px;display:flex}.elabchips button{border:1.5px solid var(--line-2);background:var(--surface);cursor:pointer;border-radius:10px;min-height:42px;padding:0 11px;font-size:14.5px}.elabchips button[aria-pressed=true]{background:var(--violet);border-color:var(--violet);color:var(--paper)}.elabside .segment{max-width:none;margin:0}.elablog{gap:2px;max-height:240px;margin:0;padding:0;font-size:15px;list-style:none;display:grid;overflow:auto}.elablog li{border-bottom:1px solid var(--line);grid-template-columns:58px 1fr;gap:8px;padding:5px 0;display:grid}.elablog b{font-variant-numeric:tabular-nums;font-weight:600}.elablog li.fire b,.elablog li.dead b{color:#d9381e}.elablog li.empty{color:var(--ink-2);border:0;display:block}.elabpresets{grid-template-columns:1fr 1fr;gap:6px;margin:0;padding:0;list-style:none;display:grid}.elabpresets button{border:1.5px solid var(--line-2);background:var(--surface);cursor:pointer;border-radius:10px;width:100%;min-height:48px;padding:4px 8px;font-size:14.5px;line-height:1.25}.elabpresets button:hover{border-color:var(--violet);color:var(--violet)}.elabsafe{color:var(--ink-2);margin:0;font-size:13.5px;line-height:1.45}.lcmore{align-items:center;min-height:44px;font-size:15.5px;font-weight:500;display:inline-flex}@media (width>=1100px){.elab{grid-template-rows:auto minmax(0,1fr);grid-template-columns:172px minmax(0,1fr) 300px;gap:8px 12px;height:100dvh;min-height:620px;padding:8px 12px 12px;overflow:hidden}.elabtop{flex-wrap:nowrap;grid-column:1/-1}.elabtools{flex-direction:column;order:0;gap:8px;padding-right:2px;overflow:hidden auto}.elabgrid{grid-template-columns:1fr 1fr;display:grid}.elabgrid button{width:auto;min-height:58px}.elabmodes{grid-template-columns:1fr 1fr}.elabmain{order:0;height:100%;min-height:0}.elabscroll{height:100%;max-height:none}.elabboard{width:calc(100% * var(--zoom,1))}.elabhint{text-align:center;flex:1 1 0;order:0}.elabside{order:0;height:100%;padding-right:2px;overflow:auto}}.elabtop .miniseg,.elabbar .miniseg{flex-wrap:nowrap;display:flex}.elabtop .miniseg button,.elabbar .miniseg button{white-space:nowrap;min-height:44px}@media (width>=1100px){.elabgrid button{min-height:50px;font-size:12px}.elabgrid svg{height:26px}.elabtools h2{margin-bottom:2px}.elabtools{gap:6px}}@media (width<=480px){.elabtop h1{flex:40%;font-size:17px}.elabtopacts{width:100%}.elabtopacts .btn{flex:1;padding:0 4px;font-size:13.5px}.elabtop .miniseg{flex:1}.elabtop .miniseg button{flex:1;padding:0 4px}}.brandmark{flex:none;gap:4px}@media (width<=370px){.appbar .brandmark .wordmark{display:none}}.wmscene{flex:none;position:relative}.wmscene>.wordmark{position:relative}.wm-dot{transform-box:fill-box;transform-origin:50%}.wmtap{cursor:pointer;z-index:3;background:0 0;border:0;border-radius:50%;width:56px;height:56px;margin:-28px 0 0 -28px;padding:0;position:absolute}.appbar .wm-dot,.lnav .wm-dot{animation:none}.wmbig .wmdot,.wmbig .wmeyes,.wmbig .wmarm{transform-box:view-box}.wmbig .wmhand{transform-box:fill-box;transform-origin:50%}.wmeyes,.wmmouth,.wmhand{opacity:0}.wmeyes{transform:scale(0)}.wmmouth{stroke-dasharray:1;stroke-dashoffset:1px}.wmhand{transform:scale(0)}.wmarm.left .wmhand{--out:7px}.wmarm.right .wmhand{--out:-7px}.greet.wmdot{animation:4.6s linear both wmbody}.greet .wmeyes{animation:4.6s linear both wmeyes}.greet .wmmouth{animation:4.6s linear both wmmouth}.greet .wmhand{animation:4.6s linear both wmhand}.greet .wmarm.right{animation:4.6s ease-in-out both wmwave}.greet .wmarm.left{animation:4.6s ease-in-out both wmwaveb}@keyframes wmeyes{0%,4%{opacity:0;transform:scale(0)}9%{opacity:1;transform:scale(1.25)}12%,33%{opacity:1;transform:scale(1)}35%{opacity:1;transform:scaleY(.12)}37%,72%{opacity:1;transform:scale(1)}78%,to{opacity:0;transform:scale(0)}}@keyframes wmmouth{0%,13%{opacity:0;stroke-dashoffset:1px}14%{opacity:1;stroke-dashoffset:1px}21%,72%{opacity:1;stroke-dashoffset:0}78%,to{opacity:0;stroke-dashoffset:0}}@keyframes wmhand{0%,22%{opacity:0;transform:translateX(var(--out)) scale(0)}25%{opacity:1;transform:translateX(var(--out)) scale(.7)}30%,68%{opacity:1;transform:none}73%,to{opacity:0;transform:translateX(var(--out)) scale(0)}}@keyframes wmwave{0%,30%{transform:rotate(0)}34%{transform:rotate(-58deg)}38%{transform:rotate(-36deg)}42%{transform:rotate(-62deg)}46%{transform:rotate(-36deg)}50%{transform:rotate(-62deg)}54%{transform:rotate(-36deg)}58%{transform:rotate(-62deg)}64%,to{transform:rotate(0)}}@keyframes wmwaveb{0%,30%{transform:rotate(0)}36%,60%{transform:rotate(14deg)}66%,to{transform:rotate(0)}}@keyframes wmbody{0%,2%{transform:none}6%{transform:scale(1.06,.95)}10%,24%{transform:none}28%{transform:scale(1.04,.97)}32%,68%{transform:none}73%{transform:scale(1.16,.8)}82%{transform:translateY(-20px)scale(.92,1.1)}90%{transform:translateY(0)scale(1.18,.78)}95%{transform:translateY(-3px)scale(.97,1.03)}to{transform:none}}.orline{color:var(--ink-2);align-items:center;gap:12px;font-size:14.5px;display:flex}.orline:before,.orline:after{content:"";background:var(--line-2);flex:1;height:1px}.googlebtn{gap:10px;background:var(--surface)!important;color:var(--ink)!important;border-color:var(--line-2)!important}.landing{--violet-2:#8f7ce8;min-height:100vh}@media (prefers-color-scheme:dark){:root:not([data-theme=light]) .landing{--violet-2:#6e5ad0}}:root[data-theme=dark] .landing{--violet-2:#6e5ad0}@media (prefers-reduced-motion:no-preference){html:has(.landing){scroll-behavior:smooth}}.lwrap{max-width:1200px;margin:0 auto;padding-inline:clamp(16px,5vw,64px)}.landing section[id]{scroll-margin-top:96px}.lnav{z-index:5;background:var(--paper);border-bottom:1px solid #0000;transition:border-color .2s;position:sticky;top:0}.lnav.lifted{border-color:var(--line)}.lnav-in{justify-content:space-between;align-items:center;gap:12px;min-height:72px;display:flex}.lbrand{color:var(--ink);align-items:center;gap:10px;min-height:44px;font-weight:600;text-decoration:none;display:inline-flex}.llinks{align-items:center;gap:clamp(12px,3vw,32px);font-size:16px;display:flex}.llinks a{color:var(--ink-2);white-space:nowrap;align-items:center;min-height:44px;text-decoration:none;display:inline-flex}.llinks a:hover{color:var(--violet)}.llinks .lcta,.llinks .lcta:hover{color:var(--paper);background:var(--violet);border-radius:8px;padding:0 16px;font-weight:500}.llinks .lcta:hover,.lbtn:hover{filter:brightness(.88)}@media (width<=480px){.lbrand span{display:none}}.lhero{flex-wrap:wrap;align-items:center;gap:clamp(36px,6vw,88px);padding-block:clamp(20px,5vw,64px) clamp(72px,10vw,128px);display:flex}.lhero-text{flex-direction:column;flex:380px;align-items:flex-start;gap:36px;min-width:0;display:flex}.lbtn{background:var(--violet);min-height:58px;color:var(--paper);border-radius:10px;align-items:center;padding:0 34px;font-weight:500;text-decoration:none;display:inline-flex}.hero-art{flex:420px;min-width:0;max-width:100%;height:auto;display:block}.wide-art{width:100%;height:auto;display:block}.lsect{padding-bottom:clamp(88px,12vw,168px)}.lthree{grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:clamp(48px,6vw,80px);display:grid}.lthree>div{align-content:start;gap:20px;display:grid}.lthree svg{width:100%;height:auto;display:block}.lthree h2{font-size:22px;font-weight:500;line-height:1.35}.lstack{flex-direction:column;gap:32px;display:flex}.lend{align-items:flex-start;padding-bottom:clamp(72px,10vw,136px)}.lbig{font:400 clamp(30px, 4.4vw, 52px)/1.22 var(--math);letter-spacing:-.01em;max-width:18em}.lnote{color:var(--ink-2);font-size:16px}.lfoot{border-top:1px solid var(--line);color:var(--ink-2);flex-wrap:wrap;justify-content:space-between;align-items:center;gap:8px 24px;padding:20px 0 28px;font-size:15px;display:flex}.lfoot-links{gap:20px;display:flex}.lfoot a{color:var(--ink-2);text-underline-offset:3px;align-items:center;min-height:44px;display:inline-flex}.lfoot a:hover{color:var(--violet)}.fx .a{transform-box:fill-box;animation-duration:.45s;animation-delay:var(--d,0s);animation-timing-function:cubic-bezier(.2,.7,.2,1);animation-play-state:paused;animation-fill-mode:both}.fx.in .a{animation-play-state:running}.fx .rise{animation-name:l-rise}.fx .sweep{transform-origin:0;animation-name:l-sweep}.fx .pop{transform-origin:50%;animation-name:l-pop}.fx .slide{animation-name:l-slide;animation-duration:.55s}.fx .grow-y{transform-origin:top;animation-name:l-grow-y}.fx .halo{animation-name:l-halo;animation-duration:.7s}@keyframes l-rise{0%{opacity:0;transform:translateY(8px)}}@keyframes l-sweep{0%{transform:scaleX(0)}}@keyframes l-pop{0%{opacity:0;transform:scale(.4)}}@keyframes l-slide{0%{opacity:0;transform:translate(-90px)}}@keyframes l-grow-y{0%{transform:scaleY(0)}}@keyframes l-halo{0%{opacity:0;transform:scale(.3)}60%{opacity:1;transform:scale(1.12)}to{transform:scale(1)}}@media (prefers-reduced-motion:reduce){.fx .a{animation:none!important}html{scroll-behavior:auto}}.lhero h1{font:600 clamp(36px, 4.6vw, 60px)/1.2 var(--ui);letter-spacing:-.02em}.lhero-text{gap:20px}.leyebrow{color:var(--violet);font-size:16px;font-weight:600}.lsub{color:var(--ink-2);max-width:30em;font-size:clamp(18px,1.7vw,21px);line-height:1.55}.lbig{font:600 clamp(27px, 3.5vw, 42px)/1.28 var(--ui);letter-spacing:-.012em}.lbtn{margin-top:8px}.ltwo{gap:18px;display:grid}.lsubject{background:var(--soft-c);border-radius:22px;align-content:start;gap:14px;padding:clamp(22px,3vw,36px);scroll-margin-top:96px;display:grid}.lsubject.math{--c:var(--toan);--soft-c:var(--toan-soft)}.lsubject.physics{--c:var(--ly);--soft-c:var(--ly-soft)}.lsubject h2{font:600 clamp(28px, 3vw, 38px)/1.2 var(--ui);color:var(--c)}.lsubjectart{color:var(--c);max-width:260px}.lsubjectart svg{width:100%;height:auto;display:block}.lsubject ul{gap:8px;margin:0;padding:0;font-size:17.5px;list-style:none;display:grid}.lsubject li{padding-left:22px;position:relative}.lsubject li:before{content:"";background:var(--c);border-radius:50%;width:9px;height:9px;position:absolute;top:.62em;left:2px}.lmore{background:var(--c);min-height:48px;color:var(--paper);border-radius:10px;justify-self:start;align-items:center;margin-top:6px;padding:0 22px;font-weight:600;text-decoration:none;display:inline-flex}.lsplit{align-items:center;gap:28px;display:grid}.ldemo{background:var(--surface);min-width:0;box-shadow:0 0 0 1.5px var(--line);border-radius:22px;padding:clamp(10px,2vw,20px)}.demohold{min-height:260px}.phys{--violet:var(--ly);--violet-soft:var(--ly-soft)}.llinks .lcta{min-height:46px}@media (width<=640px){.lhide{display:none!important}}@media (width>=820px){.ltwo{grid-template-columns:1fr 1fr;gap:24px}.lsplit{grid-template-columns:1fr 1.2fr;gap:56px}.lsplit.reverse>:first-child{order:2}}.hero-art{max-width:520px}.lstory{place-items:center start;gap:28px;display:grid}.lstorymark{min-height:200px}@media (width>=820px){.lstory{grid-template-columns:auto 1fr;gap:72px}.lstorymark{padding-left:12px}}.lbrand{min-height:48px}.lbrand span{display:none}.lmascot{margin-bottom:-6px}.lbrand{gap:6px}.lhero h1{font-size:clamp(29px,9.3vw,52px)}.lhero-text{flex:540px}.hero-art{flex:380px}
