@font-face{font-family:Inter;font-style:normal;font-weight:100 900;font-display:swap;src:url(/_next/static/media/ba9851c3c22cd980-s.woff2) format("woff2");unicode-range:u+0460-052f,u+1c80-1c8a,u+20b4,u+2de0-2dff,u+a640-a69f,u+fe2e-fe2f}@font-face{font-family:Inter;font-style:normal;font-weight:100 900;font-display:swap;src:url(/_next/static/media/21350d82a1f187e9-s.woff2) format("woff2");unicode-range:u+0301,u+0400-045f,u+0490-0491,u+04b0-04b1,u+2116}@font-face{font-family:Inter;font-style:normal;font-weight:100 900;font-display:swap;src:url(/_next/static/media/c5fe6dc8356a8c31-s.woff2) format("woff2");unicode-range:u+1f??}@font-face{font-family:Inter;font-style:normal;font-weight:100 900;font-display:swap;src:url(/_next/static/media/19cfc7226ec3afaa-s.woff2) format("woff2");unicode-range:u+0370-0377,u+037a-037f,u+0384-038a,u+038c,u+038e-03a1,u+03a3-03ff}@font-face{font-family:Inter;font-style:normal;font-weight:100 900;font-display:swap;src:url(/_next/static/media/df0a9ae256c0569c-s.woff2) format("woff2");unicode-range:u+0102-0103,u+0110-0111,u+0128-0129,u+0168-0169,u+01a0-01a1,u+01af-01b0,u+0300-0301,u+0303-0304,u+0308-0309,u+0323,u+0329,u+1ea0-1ef9,u+20ab}@font-face{font-family:Inter;font-style:normal;font-weight:100 900;font-display:swap;src:url(/_next/static/media/8e9860b6e62d6359-s.woff2) format("woff2");unicode-range:u+0100-02ba,u+02bd-02c5,u+02c7-02cc,u+02ce-02d7,u+02dd-02ff,u+0304,u+0308,u+0329,u+1d00-1dbf,u+1e00-1e9f,u+1ef2-1eff,u+2020,u+20a0-20ab,u+20ad-20c0,u+2113,u+2c60-2c7f,u+a720-a7ff}@font-face{font-family:Inter;font-style:normal;font-weight:100 900;font-display:swap;src:url(/_next/static/media/e4af272ccee01ff0-s.p.woff2) format("woff2");unicode-range:u+00??,u+0131,u+0152-0153,u+02bb-02bc,u+02c6,u+02da,u+02dc,u+0304,u+0308,u+0329,u+2000-206f,u+20ac,u+2122,u+2191,u+2193,u+2212,u+2215,u+feff,u+fffd}@font-face{font-family:Inter Fallback;src:local("Arial");ascent-override:90.44%;descent-override:22.52%;line-gap-override:0.00%;size-adjust:107.12%}.__className_f367f3{font-family:Inter,Inter Fallback;font-style:normal}.__variable_f367f3{--font-sans:"Inter","Inter Fallback"}:root{color-scheme:light;--bg:#f4f1eb;--ink:#1a1714;--muted:#6b645b;--card:#fffcf8;--line:#e4ddd3;--accent:#1d4ed8;--shadow:0 12px 40px rgba(28,25,23,0.08);--weak:#f4d6d0;--developing:#f3e4c2;--strong:#d6ead4;--untouched:#efe8dc}*{box-sizing:border-box}body,html{margin:0;padding:0}body{min-height:100vh;font-family:var(--font-sans),"Inter",system-ui,sans-serif;background:var(--bg);color:var(--ink)}main{max-width:44rem;margin:0 auto;padding:2rem 1.15rem 4rem}.top{display:flex;justify-content:space-between;gap:1rem;align-items:flex-start;margin-bottom:1.5rem}.brand{margin:0 0 .2rem;letter-spacing:.04em;text-transform:uppercase;font-size:.78rem;color:var(--muted)}h1,h2{font-weight:600;letter-spacing:-.02em;margin:0 0 .4rem}h1{font-size:1.85rem}h2{font-size:1.35rem}.eyebrow,.hint,.lede{color:var(--muted);line-height:1.5}.lede{margin:0;max-width:34rem}.eyebrow{margin:0 0 .35rem;font-size:.82rem;text-transform:uppercase;letter-spacing:.05em}.heatmap,.step{background:var(--card);border:1px solid var(--line);border-radius:1rem;padding:1.15rem 1.15rem 1.25rem;margin-bottom:1rem;box-shadow:var(--shadow)}.banner{background:var(--weak);border-radius:.6rem;padding:.7rem .8rem;margin:0 0 1rem;line-height:1.45}.banner[data-ok=true]{background:var(--strong)}.choice-list{list-style:none;margin:1rem 0 0;padding:0;display:grid;grid-gap:.55rem;gap:.55rem}.choice-list button{width:100%;display:flex;align-items:flex-start;gap:.7rem;text-align:left;border-radius:.85rem;padding:.7rem .85rem}.choice-list button .choice-letter{flex:0 0 1.5rem;font-weight:700;color:#1d4ed8}.choice-list button .choice-body{flex:1 1 auto;min-width:0}.choice-list button.primary .choice-letter{color:inherit}.choice-list button[data-result=correct]{background:#d6ead4;border-color:#047857;color:#065f46}.choice-list button[data-result=wrong]{background:#f4d6d0;border-color:#b91c1c;color:#9f1239}.choice-list button[data-result=correct] .choice-letter,.choice-list button[data-result=wrong] .choice-letter{color:inherit}.practice .primary{margin-top:.85rem}blockquote{margin:0 0 1rem;padding:0 0 0 .9rem;border-left:3px solid var(--accent);line-height:1.5}.concept-diagram{margin:0 0 1rem;padding:.75rem .85rem .7rem;border:1px solid var(--line);border-radius:.65rem;background:var(--card)}.concept-diagram-frame svg{display:block;width:100%;max-width:22rem;height:auto;margin:0 auto}.concept-diagram figcaption{margin:.55rem 0 0;font-size:.85rem;color:var(--muted);line-height:1.4}.concept-diagram.is-compact{margin:0 0 .65rem;padding:.5rem .6rem .45rem}.concept-diagram.is-compact .concept-diagram-frame svg{max-width:18rem}.concept-diagram[data-lit=true] .concept-diagram-frame svg>*{opacity:.28;transition:opacity .3s ease}.concept-diagram[data-lit=true] .concept-diagram-frame [data-part]{opacity:.28}.concept-diagram[data-lit=true] .concept-diagram-frame [data-part].is-hot,.concept-diagram[data-lit=true] .concept-diagram-frame [data-part].is-hot *{opacity:1}.concept-diagram[data-lit=true] .concept-diagram-frame [data-part].is-hot{animation:diagram-pulse 1.1s ease-out 1}@keyframes diagram-pulse{0%{opacity:.2}to{opacity:1}}@media (prefers-reduced-motion:reduce){.concept-diagram[data-lit=true] .concept-diagram-frame [data-part].is-hot{animation:none}}.teach-box .concept-diagram{margin:0 0 .75rem}.example,.practice{margin-bottom:1rem}.example p,.practice p,.step>p{line-height:1.5}.steps{margin:.6rem 0 0;padding-left:1.15rem}.steps li{margin:.35rem 0}.answer{background:var(--untouched);border-radius:.5rem;padding:.65rem .75rem}button{font:inherit;border:1px solid var(--line);background:var(--card);color:var(--ink);border-radius:999px;padding:.45rem .85rem;cursor:pointer}button.primary{background:var(--ink);color:var(--card);border-color:var(--ink)}button.ghost{background:transparent}button:disabled{opacity:.45;cursor:not-allowed}.marks{display:flex;flex-wrap:wrap;gap:.45rem;margin-top:.85rem}.controls{display:flex;gap:.65rem;flex-shrink:0}.controls,.switch{align-items:center}.switch{display:inline-flex;gap:.4rem;color:var(--muted);font-size:.95rem}.hint-box{margin:1rem 0 0;padding:.85rem .9rem;border-radius:.65rem;background:var(--untouched)}.hint-box p{margin:0 0 .7rem;line-height:1.5}.hint-box .eyebrow{margin-bottom:.35rem}.math-text .katex{font-size:1.05em}.math-text strong{font-weight:700}.math-text em{font-style:italic}.math-text code{font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:.92em}.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.source-tag{display:inline-block;margin:0 .4rem .35rem 0;font-size:.75rem;font-weight:650;letter-spacing:.04em;text-transform:uppercase;color:var(--muted)}.symbol-legend{margin:.85rem 0 0;padding:.7rem .8rem;border-radius:.65rem;background:#f6f1e8}.symbol-legend dl{margin:.35rem 0 0}.symbol-legend dl>div{display:grid;grid-template-columns:auto 1fr;grid-gap:.35rem .7rem;gap:.35rem .7rem;margin:.3rem 0}.symbol-legend dt{margin:0;font-weight:700}.symbol-legend dd{margin:0}.ask-box,.teach-box{margin:1rem 0 0;padding:.85rem .9rem;border-radius:.65rem;border:1px solid var(--line);background:var(--card)}.ask-box p,.teach-box p{margin:0 0 .65rem}.ask-chips{flex-wrap:wrap;gap:.4rem}.ask-chips,.ask-thread{display:flex;margin:0 0 .7rem}.ask-thread{flex-direction:column;gap:.55rem;max-height:18rem;overflow-y:auto;padding:.55rem .15rem .7rem;border-top:1px solid var(--line);border-bottom:1px solid var(--line)}.ask-empty{margin:0;color:var(--muted);font-size:.92rem}.ask-row{display:flex;width:100%}.ask-row-student{justify-content:flex-end}.ask-row-coach{justify-content:flex-start}.ask-bubble{max-width:min(92%,22rem);padding:.5rem .7rem .55rem;border-radius:.85rem;line-height:1.5}.ask-bubble .source-tag{display:block;margin:0 0 .2rem}.ask-bubble-student{background:#e8eef9;color:var(--ink);border-bottom-right-radius:.25rem}.ask-bubble-coach{background:var(--untouched);border-bottom-left-radius:.25rem}.ask-form{display:flex;gap:.5rem}.ask-form input{flex:1 1;font:inherit;border:1px solid var(--line);border-radius:.7rem;padding:.5rem .7rem}.heatmap h2{margin-bottom:.75rem}.heatmap ol{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(2,minmax(0,1fr));grid-gap:.5rem;gap:.5rem}.heatmap li{border-radius:.65rem;padding:.7rem .75rem;background:var(--untouched);border:1px solid transparent}.heatmap li[data-label=weak]{background:var(--weak)}.heatmap li[data-label=developing]{background:var(--developing)}.heatmap li[data-label=strong]{background:var(--strong)}.heatmap li[data-label=mastered]{background:#b7d6b4}.heatmap li[data-current=true]{border-color:var(--ink)}.heatmap-name{display:block;font-size:.95rem}.heatmap-label{display:block;margin-top:.2rem;color:var(--muted);font-size:.82rem}.form{display:grid;grid-gap:.75rem;gap:.75rem;margin:1.25rem 0}.form label,.hint{display:grid;grid-gap:.3rem;gap:.3rem}.form .switch{display:inline-flex}.form .auth-age{display:flex}.form input,input[type=range]{font:inherit;width:100%}.field{display:grid;grid-gap:.35rem;gap:.35rem}.field>span:first-child{font-size:.88rem;color:var(--muted)}.auth-form input[type=email],.auth-form input[type=password],.auth-form input[type=text]{border:1px solid var(--line);border-radius:.75rem;padding:.78rem .9rem;background:#fff;transition:border-color .15s ease,box-shadow .15s ease}.auth-form input:focus{outline:none;border-color:var(--accent);box-shadow:0 0 0 4px rgba(29,78,216,.12)}.password-wrap{position:relative;display:block}.password-wrap input{padding-right:4.4rem}.password-toggle{position:absolute;top:50%;right:.45rem;transform:translateY(-50%);border:0;background:transparent;color:var(--muted);padding:.3rem .55rem;font-size:.82rem}.password-meter{display:grid;grid-template-columns:1fr 1fr 1fr auto;grid-gap:.35rem;gap:.35rem;align-items:center}.password-meter i{height:4px;border-radius:99px;background:var(--line)}.password-meter[data-score="1"] i:first-child{background:#b45309}.password-meter[data-score="2"] i:first-child,.password-meter[data-score="2"] i:nth-child(2){background:#ca8a04}.password-meter[data-score="3"] i{background:#3f7d4a}.password-meter em{font-style:normal;font-size:.75rem;color:var(--muted)}.topics{list-style:none;padding:0;display:grid;grid-gap:.75rem;gap:.75rem}.topics a{color:inherit;text-decoration:none;display:block}.topics .disabled{opacity:.55}.button-link{display:inline-block;margin-top:.75rem;text-decoration:none}a{color:var(--accent)}@media (max-width:560px){.top{flex-direction:column}.heatmap ol{grid-template-columns:1fr}}