/* Classroom shell. Shares the portfolio's ivory, green, and typography. */
.classroom { --maxw: 1480px; }
.icon { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-width: 1.5; stroke-linecap: round; stroke-linejoin: round; flex: none; }
.svg-defs { position: absolute; width: 0; height: 0; overflow: hidden; }
.classroom-shell { display: grid; grid-template-columns: 252px minmax(0,1fr); max-width: 1600px; margin: auto; }
.classroom-side { position: sticky; top: 0; height: 100dvh; padding: 36px 24px 25px; border-right: 1px solid var(--line); display: flex; flex-direction: column; z-index: 30; }
.classroom-brand { display: flex; align-items: center; gap: 12px; }
.quantum-mark { display: grid; place-items: center; width: 44px; height: 48px; color: var(--accent); }
.quantum-mark .icon { width: 42px; height: 42px; stroke-width: 1.1; }
.brand-title { font-size: 17px; font-weight: 600; letter-spacing: -.04em; line-height: 1.22; }
.brand-caption { font: 10px var(--mono); color: var(--ink-3); margin-top: 6px; }
.side-description { margin-top: 30px; font-size: 13px; color: var(--ink-2); line-height: 1.75; }
.side-description a { color: var(--ink); border-bottom: 1px solid var(--line); }
.classroom-nav { display: grid; gap: 5px; margin-top: 32px; }
.classroom-nav a { display: flex; gap: 12px; align-items: center; color: var(--ink-2); padding: 12px; font-size: 13px; border-radius: 8px; position: relative; }
.classroom-nav .icon { width: 17px; height: 17px; }
.classroom-nav a:hover, .classroom-nav a[aria-current] { background: var(--accent-soft); color: var(--accent); }
.classroom-nav a[aria-current]::before { content: ''; position: absolute; left: 0; width: 2px; height: 16px; background: var(--accent); }
.side-bottom { margin-top: auto; padding-top: 30px; }
.side-feature { border: 1px solid var(--line); background: var(--paper-2); border-radius: 10px; padding: 17px; }
.side-feature .tiny { color: var(--accent); }
.side-feature p { font-size: 12px; color: var(--ink-2); margin: 9px 0 13px; line-height: 1.65; }
.side-feature a { font-size: 12px; color: var(--accent); display: flex; justify-content: space-between; }
.side-links { display: flex; gap: 23px; margin-top: 22px; font-size: 12px; color: var(--ink-2); }
.side-foot { display: flex; justify-content: space-between; align-items: center; margin-top: 20px; padding-top: 17px; border-top: 1px solid var(--line); }
.tiny { font: 9px/1.6 var(--mono); text-transform: uppercase; letter-spacing: .1em; color: var(--ink-3); }
.theme-toggle { border: 1px solid var(--line); background: var(--paper); width: 35px; height: 35px; border-radius: 50%; display: grid; place-items: center; cursor: pointer; color: var(--ink-2); flex: none; }
.theme-toggle .icon { width: 16px; height: 16px; }
.theme-toggle .sun, [data-theme="dark"] .theme-toggle .moon { display: none; }
[data-theme="dark"] .theme-toggle .sun { display: block; }
.mobile-menu { display: none; }
.classroom-main { min-width: 0; padding-inline: clamp(28px,4.5vw,68px); }
.classroom .wrap { max-width: none; padding: 0; }
.topline { display: flex; justify-content: space-between; gap: 20px; padding-top: 36px; font: 10px var(--mono); letter-spacing: .07em; text-transform: uppercase; color: var(--ink-3); }
.status { display: flex; align-items: center; gap: 9px; }
.status-dot { width: 6px; height: 6px; background: var(--accent); border-radius: 50%; box-shadow: 0 0 0 4px var(--accent-soft); }
.topline a { color: var(--ink-2); }
.chero { padding: 65px 0 42px; }
.hero-grid { display: grid; grid-template-columns: minmax(0,1.1fr) minmax(300px,.85fr); gap: clamp(25px,4vw,55px); align-items: center; }
.hero-copy { min-width: 0; }
.kick { color: var(--accent); font: 10px var(--mono); letter-spacing: .12em; text-transform: uppercase; margin-bottom: 22px; }
.chero h1 { font: 500 clamp(36px,4.15vw,64px)/1.07 var(--sans); letter-spacing: -.05em; }
.chero h1 span { display: block; }
.chero h1 em { font: italic 400 1.18em/1.02 var(--serif); color: var(--accent); letter-spacing: -.025em; }
.chero .sub { color: var(--ink-2); font-size: 16px; line-height: 1.8; margin-top: 25px; max-width: 44ch; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 28px; }
.classroom .btn { font-family: var(--sans); font-size: 13px; letter-spacing: 0; padding: 12px 18px; border-radius: 999px; }
.classroom .btn:hover { background: var(--accent); color: var(--paper); border-color: var(--accent); }
.classroom .btn-ghost:hover { background: var(--accent-soft); color: var(--accent); }
.hero-note { display: flex; gap: 7px; align-items: center; color: var(--ink-3); font-size: 11px; margin-top: 17px; }
.hero-note .icon { width: 13px; height: 13px; color: var(--accent); }
.qubit-lab { background: var(--surface); border: 1px solid var(--line); border-radius: 17px; padding: 22px; box-shadow: 0 2px 3px rgb(32 46 45 / .03), 0 24px 40px -27px rgb(32 46 45 / .25); }
.lab-label { display: flex; align-items: center; justify-content: space-between; gap: 12px; }
.lab-label .tiny { font-size: 9px; }
.live-badge { border: 1px solid var(--line); border-radius: 30px; padding: 3px 7px; display: flex; align-items: center; gap: 5px; font: 8px var(--mono); color: var(--accent); text-transform: uppercase; }
.live-badge::before { content: ''; width: 4px; height: 4px; background: currentColor; border-radius: 50%; }
.qubit-lab h2 { font: 400 26px var(--serif); margin-top: 10px; }
.bloch-sphere { width: 100%; height: 205px; display: block; color: var(--accent); }
.sphere-fill { fill: var(--accent-soft); fill-opacity: .55; stroke: var(--line-strong); }
.sphere-axis { stroke: var(--line-strong); fill: none; stroke-width: 1; }
.sphere-label { font: 12px var(--mono); fill: var(--ink-3); }
.sphere-ket { font: italic 18px var(--serif); fill: var(--ink); }
.sphere-vector { stroke: var(--accent); stroke-width: 2.5; stroke-linecap: round; transition: all .35s ease; }
.sphere-tip { fill: var(--accent); transition: all .35s ease; }
.sphere-halo { fill: var(--accent); opacity: .1; transition: all .35s ease; }
.mini-circuit { position: relative; display: flex; align-items: center; gap: 9px; min-height: 34px; margin: 4px 0 15px; padding: 0 8px; overflow: hidden; font: 11px var(--mono); }
.mini-circuit::before { content: ''; position: absolute; height: 1px; top: 50%; left: 35px; right: 8px; background: var(--line-strong); }
.mini-circuit span { position: relative; background: var(--surface); }
.circuit-gates { display: flex; gap: 8px; }
.circuit-gates b { display: grid; place-items: center; width: 28px; height: 28px; border: 1px solid var(--line-strong); border-radius: 5px; font-weight: 400; background: var(--accent-soft); }
.circuit-empty { color: var(--ink-3); margin-left: 12px; font-size: 9px; padding: 2px 8px; }
.gate-controls { display: flex; gap: 7px; align-items: center; }
.gate-controls button { min-width: 38px; min-height: 34px; border: 1px solid var(--line-strong); border-radius: 7px; background: var(--paper); font: 12px var(--mono); cursor: pointer; color: var(--ink); }
.gate-controls button:hover { background: var(--accent-soft); border-color: var(--accent); }
.gate-controls .reset-gates { margin-left: auto; padding-inline: 10px; color: var(--ink-3); font-size: 10px; }
.probability-readout { border-top: 1px solid var(--line); margin-top: 16px; padding-top: 13px; display: grid; gap: 8px; }
.prob-row { display: grid; grid-template-columns: 23px 1fr 36px; align-items: center; gap: 10px; font: 10px var(--mono); color: var(--ink-2); }
.prob-track { height: 5px; border-radius: 4px; background: var(--line); overflow: hidden; }
.prob-fill { height: 100%; width: 100%; background: var(--accent); border-radius: inherit; transition: width .35s ease; }
.prob-row:last-child .prob-fill { width: 0; background: #9baa7f; }
.gate-explanation { min-height: 43px; margin-top: 13px; font-size: 11px; line-height: 1.6; color: var(--ink-2); }
.resource-stats { display: grid; grid-template-columns: repeat(4,1fr); padding-top: 30px; margin-top: 38px; border-top: 1px solid var(--line); }
.resource-stat { padding-left: 23px; border-left: 1px solid var(--line); display: flex; gap: 13px; align-items: center; }
.resource-stat:first-child { padding-left: 0; border: 0; }
.resource-stat b { font: 36px/1 var(--serif); color: var(--ink); }
.resource-stat span { font-size: 11px; line-height: 1.5; color: var(--ink-2); }
.start-strip { display: grid; grid-template-columns: 40px 1fr auto; align-items: center; gap: 17px; padding: 21px 24px; background: var(--accent-soft); border: 1px solid var(--line); border-radius: 11px; margin: 5px 0 12px; }
.start-strip .icon { color: var(--accent); width: 30px; height: 30px; }
.start-strip h2 { font-size: 14px; font-weight: 500; }
.start-strip p { font-size: 12px; color: var(--ink-2); margin-top: 3px; }
.start-strip a { color: var(--accent); font-size: 12px; white-space: nowrap; }
.classroom .section { padding-block: 55px; scroll-margin-top: 24px; }
.section-intro { display: flex; justify-content: space-between; align-items: flex-end; gap: 25px; margin-bottom: 22px; }
.classroom .eyebrow { font-size: 10px; color: var(--accent); margin-bottom: 14px; letter-spacing: .09em; }
.classroom .eyebrow::after { width: 28px; flex: none; background: var(--line-strong); }
.section-intro h2 { font: 400 clamp(32px,3.5vw,46px)/1.05 var(--serif); }
.section-copy { color: var(--ink-2); font-size: 13px; line-height: 1.75; max-width: 40ch; }
.section-copy a { color: var(--accent); }
.library-tools { display: flex; justify-content: space-between; gap: 15px; align-items: center; flex-wrap: wrap; margin-bottom: 17px; }
.library-note { display: flex; gap: 3px; flex-wrap: wrap; background: var(--surface); padding: 4px; border: 1px solid var(--line); border-radius: 30px; }
.library-filter { background: transparent; border: 0; padding: 8px 12px; border-radius: 22px; font: 11px var(--sans); color: var(--ink-2); cursor: pointer; }
.library-filter[aria-pressed="true"] { background: var(--ink); color: var(--paper); }
.library-search { display: flex; align-items: center; gap: 8px; padding: 9px 12px; border: 1px solid var(--line); border-radius: 30px; background: var(--surface); }
.library-search .icon { width: 14px; height: 14px; color: var(--ink-3); }
.library-search input { width: 135px; min-width: 0; color: var(--ink); background: transparent; border: 0; outline: none; font: 12px var(--sans); }
.library-search:focus-within { outline: 2px solid var(--accent); outline-offset: 3px; }
.library-filter-status { font: 10px var(--mono); color: var(--ink-3); margin-bottom: 17px; }
.path-group { border-top: 1px solid var(--line); }
.path-group:last-child { border-bottom: 1px solid var(--line); }
.path-group summary { display: grid; grid-template-columns: 40px 1fr auto 16px; align-items: center; gap: 14px; padding: 20px 0; cursor: pointer; list-style: none; }
.path-group summary::-webkit-details-marker { display: none; }
.path-group summary::after { content: '+'; font: 19px var(--mono); color: var(--accent); }
.path-group[open] summary::after { content: '−'; }
.path-index { display: grid; place-items: center; width: 38px; height: 38px; background: var(--accent-soft); border: 1px solid var(--line); border-radius: 9px; color: var(--accent); }
.path-index .icon { width: 20px; height: 20px; }
.path-title { font-size: 16px; font-weight: 500; letter-spacing: -.015em; }
.path-description { display: block; color: var(--ink-3); font-size: 11px; line-height: 1.6; margin-top: 3px; }
.path-count { color: var(--ink-3); font: 9px var(--mono); white-space: nowrap; }
.track-grid { display: grid; grid-template-columns: repeat(3,minmax(0,1fr)); gap: 12px; padding: 3px 0 24px; }
.track { padding: 19px; border: 1px solid var(--line); border-radius: 10px; display: flex; flex-direction: column; position: relative; background: var(--surface); min-height: 214px; transition: border-color .2s, transform .2s, box-shadow .2s; }
.track:hover { transform: translateY(-3px); border-color: var(--accent); box-shadow: 0 12px 22px -18px var(--accent); }
.track-icon { color: var(--accent); margin-bottom: 19px; }
.track-icon .icon { width: 24px; height: 24px; stroke-width: 1.3; }
.tnum { display: none; }
.track .src { position: absolute; right: 17px; top: 19px; color: var(--ink-3); font: 8px var(--mono); letter-spacing: .05em; text-transform: uppercase; border: 1px solid var(--line); padding: 3px 6px; border-radius: 30px; }
.track h3 { font: 500 15px/1.35 var(--sans); letter-spacing: -.02em; }
.track p { font-size: 12px; color: var(--ink-2); line-height: 1.7; margin-top: 10px; flex: 1; }
.track .go { font-size: 11px; color: var(--accent); display: flex; justify-content: space-between; margin-top: 19px; }
.track[hidden], .path-group[hidden], .empty-library[hidden] { display: none; }
.empty-library { padding: 35px; text-align: center; color: var(--ink-2); font-size: 14px; border: 1px dashed var(--line); border-radius: 10px; }
.lab-promo { border: 1px solid var(--line); border-radius: 16px; background: var(--block); color: var(--block-ink); margin: 0 0 8px; padding: 34px!important; }
.classroom .lab-promo .eyebrow { color: var(--block-muted); }
.lab-promo-grid { display: grid; grid-template-columns: 1.2fr .85fr; gap: 35px; align-items: center; }
.lab-promo h2 { font: 400 clamp(32px,3.4vw,46px)/1.08 var(--serif); max-width: 15ch; }
.lab-promo p { font-size: 13px; color: var(--block-muted); line-height: 1.75; margin-top: 16px; max-width: 42ch; }
.lab-promo-link { display: inline-flex; gap: 20px; margin-top: 24px; font-size: 12px; background: #d3e4cf; color: #202e2d; padding: 11px 17px; border-radius: 30px; }
.code-preview { background: #172321; border: 1px solid #3a4a43; border-radius: 10px; overflow: hidden; transform: rotate(-2deg); }
.code-preview-head { display: flex; justify-content: space-between; border-bottom: 1px solid #34443f; padding: 11px 13px; font: 9px var(--mono); color: #a9b6ae; }
.code-preview pre { font: 11px/2 var(--mono); color: #e3e8df; padding: 17px; overflow-x: auto; }
.code-preview .comment { color: #8caaa0; }
.code-preview .keyword { color: #9bcbb4; }
.code-preview-foot { color: #a5d0b4; padding: 11px 14px; border-top: 1px solid #34443f; font: 9px var(--mono); }
.writing-layout { display: grid; grid-template-columns: 1.1fr .8fr; gap: 18px; }
.latest-writing { border: 1px solid var(--line); border-radius: 12px; padding: 27px; background: var(--surface); }
.latest-writing .meta, .series-panel .meta { font: 9px var(--mono); letter-spacing: .06em; color: var(--accent); text-transform: uppercase; }
.article-art { width: 100%; height: 80px; margin: 22px 0; color: var(--accent); }
.latest-writing h3 { font: 400 32px/1.1 var(--serif); max-width: 21ch; }
.latest-writing p { font-size: 12px; color: var(--ink-2); line-height: 1.75; margin-top: 13px; }
.text-link { display: inline-flex; margin-top: 22px; color: var(--accent); font-size: 12px; gap: 8px; }
.series-panel { padding: 21px 5px 21px 15px; }
.series-panel h3 { font: 400 27px var(--serif); margin-top: 12px; }
.series-list { margin-top: 23px; border-top: 1px solid var(--line); }
.series-item { display: grid; grid-template-columns: 20px 1fr auto; gap: 10px; align-items: center; padding: 19px 0; border-bottom: 1px solid var(--line); }
.series-item .sn, .series-item .sc { font: 9px var(--mono); color: var(--ink-3); }
.series-item .st { font-size: 12px; }
.series-item:hover { color: var(--accent); }
.archive { border-block: 1px solid var(--line); }
.archive summary { display: flex; justify-content: space-between; padding: 18px 0; color: var(--ink-2); font-size: 13px; list-style: none; cursor: pointer; }
.archive summary::after { content: '+'; color: var(--accent); }
.archive[open] summary::after { content: '−'; }
.lect-grid { display: grid; grid-template-columns: repeat(3,1fr); gap: 12px; padding-bottom: 22px; }
.lect { display: flex; flex-direction: column; gap: 14px; border: 1px solid var(--line); border-radius: 10px; padding: 20px; }
.lect:hover { border-color: var(--accent); }
.lect .ll, .lect .go { font: 9px var(--mono); color: var(--accent); }
.lect h3 { font-size: 14px; line-height: 1.5; }
.lect .go { margin-top: auto; }
.classroom .site-foot { background: transparent; padding: 30px 0; }
.classroom .foot-grid { gap: 22px; }
.classroom .foot-soc { gap: 16px; }
.classroom .foot-soc a { font: 11px var(--sans); letter-spacing: 0; }
.classroom .foot-fine { font: 10px/1.7 var(--mono); letter-spacing: 0; }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; clip: rect(0,0,0,0); overflow: hidden; white-space: nowrap; border: 0; }
@media (min-width:1500px) { .classroom-shell { grid-template-columns: 280px minmax(0,1fr); } .chero { padding-top: 80px; } }
@media (max-width:1100px) { .classroom-shell { grid-template-columns: 215px minmax(0,1fr); } .classroom-side { padding-inline: 18px; } .classroom-main { padding-inline: 30px; } .hero-grid { grid-template-columns: minmax(0,1fr) minmax(265px,.9fr); gap: 25px; } .chero h1 { font-size: 37px; } .resource-stat { padding-left: 15px; gap: 8px; } .resource-stat b { font-size: 30px; } .library-search { flex: 1; } .track-grid { grid-template-columns: repeat(2,minmax(0,1fr)); } }
@media (max-width:900px) { .classroom-shell { display: block; } .classroom-side { position: sticky; height: auto; background: var(--paper); border-right: 0; border-bottom: 1px solid var(--line); padding: 14px 24px; flex-direction: row; justify-content: space-between; align-items: center; flex-wrap: wrap; } .quantum-mark { width: 33px; height: 35px; } .quantum-mark .icon { width: 31px; height: 31px; } .brand-title { font-size: 14px; } .brand-caption { font-size: 8px; } .side-description, .side-bottom { display: none; } .mobile-menu { display: flex; align-items: center; gap: 7px; border: 1px solid var(--line); padding: 8px 12px; background: transparent; border-radius: 8px; color: var(--ink); font-size: 12px; cursor: pointer; } .mobile-menu .icon { width: 15px; height: 15px; } .classroom-nav { display: none; } .classroom-side[data-menu-open] .classroom-nav { display: grid; width: 100%; grid-template-columns: 1fr 1fr; margin-top: 15px; } .classroom-main { padding-inline: 30px; } .topline { padding-top: 25px; } .chero { padding-top: 45px; } .chero h1 { font-size: clamp(36px,5.3vw,52px); } .classroom .section { scroll-margin-top: 95px; } }
@media (max-width:620px) { .classroom-main { padding-inline: 21px; } .classroom-side { padding-inline: 20px; } .topline { font-size: 8px; } .hero-grid { grid-template-columns: 1fr; gap: 33px; } .chero { padding-top: 35px; } .chero h1 { font-size: clamp(36px,9vw,50px); } .chero .sub { font-size: 15px; } .qubit-lab { max-width: 440px; width: 100%; margin-inline: auto; } .bloch-sphere { height: 215px; } .resource-stats { grid-template-columns: 1fr 1fr; gap: 22px 0; margin-top: 30px; padding-top: 23px; } .resource-stat { padding-left: 15px; } .resource-stat:nth-child(3) { padding-left: 0; border: 0; } .resource-stat b { font-size: 35px; } .start-strip { padding: 18px; grid-template-columns: 26px 1fr; gap: 14px; } .start-strip .icon { width: 25px; } .start-strip a { grid-column: 2; } .section-intro { display: grid; gap: 16px; } .section-copy { max-width: none; } .library-tools { display: grid; gap: 12px; } .library-note { border-radius: 13px; } .library-filter { padding: 8px 9px; } .library-search input { width: 100%; } .track-grid { grid-template-columns: 1fr; } .track { min-height: 195px; } .path-group summary { gap: 10px; grid-template-columns: 34px 1fr 14px; } .path-index { width: 32px; height: 34px; } .path-count { display: none; } .path-title { font-size: 15px; } .path-description { font-size: 10px; } .classroom .section { padding-block: 40px; } .lab-promo { padding: 25px!important; } .lab-promo-grid, .writing-layout { grid-template-columns: 1fr; gap: 25px; } .lab-promo h2 { font-size: 36px; } .code-preview { transform: none; } .series-panel { padding: 0; } .lect-grid { grid-template-columns: 1fr; } }
@media (prefers-reduced-motion:reduce) { *, *::before, *::after { scroll-behavior: auto!important; transition: none!important; animation: none!important; } }

.mobile-theme{display:none}
@media(max-width:900px){.classroom-side[data-menu-open] .mobile-theme{display:grid;margin:8px 12px}}
.classroom-side{overflow-y:auto}
@media(min-width:901px) and (max-height:820px){.side-feature{display:none}}