/* Shared black appearance across the eight study sections. */
.top{flex-wrap:wrap;gap:18px}.top nav{flex:1;justify-content:center}
.theme-toggle{display:inline-flex;align-items:center;gap:8px;white-space:nowrap;border:1px solid var(--line);background:#eeeefe;color:#3e49ae;font-size:12px;padding:9px 13px;min-height:42px}.theme-toggle span{font-size:19px;line-height:1}
html[data-theme=light]{color-scheme:light}
html[data-theme=dark]{color-scheme:dark;--ink:#eff0f8;--muted:#b5b8cb;--accent:#bcb7ff;--line:#383a4b;--mint:#3d725b;--paper:#050505;--soft:#181820}
[data-theme=dark] body{background:var(--paper);color:var(--ink)}
[data-theme=dark] .top{background:#09090df5}
[data-theme=dark] :is(.panel,.lesson,.exam-page){background:#121216}
[data-theme=dark] :is(.term,.term:nth-child(2n),details,.topic-links a,.options button){background:#1c1c24;color:var(--ink);border-color:var(--line)}
[data-theme=dark] :is(.key,.feedback,.tool-controls output){background:#232136;color:#e8e5ff}
[data-theme=dark] :is(input,select,textarea){background:#0b0b10;color:var(--ink);border-color:#626178}
[data-theme=dark] :is(button,.button){background:#bcb7ff;color:#17132e}
[data-theme=dark] :is(.quiet,.theme-toggle,.file-button){background:#252332;color:#d5d1ff;border:1px solid #514b6c}
[data-theme=dark] .options button{background:#22212d;color:var(--ink);border:1px solid #514b6c}
[data-theme=dark] .flash{background:linear-gradient(130deg,#242038,#171720);color:#f2efff;border-color:#5d5675}
[data-theme=dark] .answer{color:#dbd8f0}
[data-theme=dark] .badge{background:#35304a;color:#ded8ff}
[data-theme=dark] :is(.hero-art,.canvas-wrap){background:#0c0d14;border-color:var(--line)}
[data-theme=dark] .hero-art svg [stroke="#3e49ae"]{stroke:#bcb7ff}
[data-theme=dark] .hero-art svg [fill="#3e49ae"]{fill:#d2cdff}
[data-theme=dark] .hero-art svg #grid path{stroke:#35364a}
[data-theme=dark] pre{background:#090a10;color:#e4e8f5;border:1px solid #363c50}
[data-theme=dark] .skip{background:#1c192c;color:#ded8ff}
input[type=range],input[type=checkbox]{accent-color:var(--accent)}
:is(button,a,input,select,textarea,summary):focus-visible{outline:3px solid #c795e9;outline-offset:4px}
@media(max-width:1100px){.top{flex-direction:row;align-items:center;justify-content:space-between}.top nav{order:3;flex-basis:100%;justify-content:flex-start}.top .brand small{display:none}.theme-toggle{margin-left:auto}}
@media(max-width:600px){.theme-toggle{padding:8px 10px;font-size:11px}.top .brand{font-size:21px}.brand img{width:30px;height:30px}}
@media print{.theme-toggle{display:none!important}html[data-theme=dark]{color-scheme:light;--ink:#000;--muted:#333;--paper:#fff;--line:#ccc;--accent:#000}html[data-theme=dark] :is(body,main,.exam-page,pre){background:#fff!important;color:#000!important}}