:root {
  color-scheme: dark;
  --bg: #0b1220;
  --panel: #111c2d;
  --line: #26374e;
  --ink: #e8f0fb;
  --muted: #a1b3c9;
  --subtle: #8b9eb7;
  --cyan: #78e4ed;
  --mint: #81e9c8;
  --violet: #c1a8ff;
  --warm: #ffb19c;
  font: 15px/1.55 "Microsoft YaHei UI", "PingFang SC", "Noto Sans CJK SC", system-ui, sans-serif;
  background: var(--bg);
  color: var(--ink);
}
* { box-sizing: border-box; }
body { margin: 0; min-width: 280px; }
h1, h2, h3, h4, p { margin: 0; }
button, select, input { font: inherit; }
button, select { color: inherit; }
button { cursor: pointer; }
button:disabled { cursor: default; }
button:focus-visible, select:focus-visible, input:focus-visible, a:focus-visible, summary:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
}
[hidden] { display: none !important; }
.skip { position: fixed; z-index: 4; top: 8px; left: 8px; padding: 8px 12px; background: var(--bg); color: var(--cyan); transform: translateY(-150%); }
.skip:focus { transform: translateY(0); }
.masthead {
  display: flex; align-items: center; justify-content: space-between; gap: 14px;
  min-height: 68px; padding: 10px max(24px, calc((100vw - 1600px) / 2));
  background: #0f1828; border-bottom: 1px solid var(--line);
}
.brand, .header-tools { display: flex; align-items: center; gap: 12px; }
.brand-mark { flex-shrink: 0; }
.brand h1 { font-size: 1.16rem; letter-spacing: .065em; }
.brand p, .eyebrow, .panel-label, .counter, .clock {
  font-family: "Cascadia Mono", Consolas, "Microsoft YaHei UI", monospace;
  font-size: .77rem; letter-spacing: .07em;
}
.brand p { color: var(--subtle); letter-spacing: .15em; }
.local-status { color: var(--muted); font-size: .84rem; padding-right: 7px; }
.local-status i, .signal { width: 7px; height: 7px; display: inline-block; border-radius: 50%; background: var(--cyan); box-shadow: 0 0 11px #78e4ed67; margin-right: 5px; }
.tool-button, .icon-button, .speed select {
  border: 1px solid #33455c; border-radius: 8px; background: #152238;
}
.tool-button { padding: 6px 11px; min-height: 38px; white-space: nowrap; font-size: .86rem; }
.tool-button span { color: var(--cyan); margin-right: 3px; font-weight: 700; }
.tool-button:hover, .tool-button[aria-pressed=true], .icon-button:hover:not(:disabled), .speed select:hover { background: #203749; border-color: #4a8090; }
.shell { max-width: 1648px; margin-inline: auto; padding: 0 24px; }
.lesson-head { display: flex; justify-content: space-between; gap: 16px; align-items: flex-end; padding: 17px 0 15px; }
.eyebrow { color: var(--cyan); font-weight: 650; display: flex; align-items: center; gap: 7px; }
.divider { display: inline-block; width: 1px; height: .8em; background: #496078; vertical-align: middle; margin-inline: 4px; }
.lesson-head h2 { font-size: clamp(1.72rem, 2.25vw, 2.45rem); line-height: 1.16; margin-top: 4px; letter-spacing: .025em; }
.journey { display: flex; gap: 9px; align-items: center; margin-bottom: 3px; }
.journey span { padding: 3px 10px; border: 1px solid currentColor; border-radius: 5px; font-size: .78rem; font-weight: 650; }
.journey b { color: var(--subtle); font-weight: 400; }
.journey-dna { color: var(--cyan); background: #122d3b; }
.journey-rna { color: var(--violet); background: #261f3b; }
.journey-peptide { color: var(--warm); background: #31232f; }
.workspace {
  display: grid; gap: 12px;
  grid-template-columns: minmax(155px, .75fr) minmax(380px, 3.7fr) minmax(245px, 1.16fr);
  grid-template-areas: "nav scene inspector" "dock dock dock";
}
.panel { min-width: 0; background: var(--panel); border: 1px solid var(--line); border-radius: 13px; }
.rail { grid-area: nav; display: flex; flex-direction: column; padding: 13px 9px; }
.rail-head { display: flex; justify-content: space-between; align-items: center; padding: 4px 6px 11px; gap: 3px; }
.panel-label { color: var(--muted); font-weight: 700; }
.counter { white-space: nowrap; color: var(--cyan); }
.steps { list-style: none; margin: 0; padding: 0; display: grid; gap: 5px; }
.step { text-align: left; display: flex; align-items: center; gap: 9px; width: 100%; min-height: 51px; padding: 5px 7px; border: 1px solid transparent; border-radius: 8px; background: transparent; }
.step:hover { background: #182a3e; }
.step[aria-current=step] { background: #153348; border-color: #2f687d; box-shadow: inset 3px 0 #70e6ed; }
.step-index { display: grid; place-items: center; width: 28px; height: 28px; flex: 0 0 28px; color: #b1c2d6; border: 1px solid #3c526c; border-radius: 50%; font: 700 .77rem Consolas, monospace; }
.step[aria-current=step] .step-index { color: #0c2635; background: var(--cyan); border-color: transparent; }
.step.visited:not([aria-current=step]) .step-index { color: var(--mint); border-color: #416f69; }
.step strong, .step small { display: block; }
.step strong { font-size: .91rem; line-height: 1.25; }
.step small { color: var(--muted); font-size: .73rem; margin-top: 3px; }
.rail-note { display: flex; align-items: center; gap: 8px; font-size: .75rem; color: var(--muted); border-top: 1px solid var(--line); padding: 12px 5px 0; margin: auto 3px 0; }
.rail-note-icon { font-size: 1.35rem; color: var(--cyan); }
.scene { grid-area: scene; display: flex; flex-direction: column; overflow: hidden; }
.scene-heading { padding: 11px 16px; display: flex; align-items: center; justify-content: space-between; gap: 8px; }
.scene-heading h3 { font-size: clamp(1.13rem, 1.6vw, 1.62rem); line-height: 1.25; margin-top: 4px; letter-spacing: .02em; }
.scene-heading h3:focus { outline: none; }
.model-chip, .lab-chip { color: var(--cyan); border: 1px solid #315568; background: #112b3b; border-radius: 5px; padding: 3px 7px; white-space: nowrap; font-size: .73rem; }
.viewport {
  isolation: isolate; position: relative; display: grid; align-items: center; flex: 1;
  min-height: clamp(308px, calc(100svh - 419px), 552px); overflow: hidden;
  border-block: 1px solid #21364a; background-color: #0b192a;
  background-image: radial-gradient(ellipse at 52% 47%, #153a51a6, transparent 76%), linear-gradient(#74cfe80d 1px, transparent 1px), linear-gradient(90deg, #74cfe80d 1px, transparent 1px);
  background-size: auto, 26px 26px, 26px 26px;
}
.viewport::after { content: ""; position: absolute; inset: 8px; border: 1px solid #79d6e017; border-radius: 3px; pointer-events: none; }
#art { display: block; width: 100%; height: 100%; min-height: 0; position: absolute; inset: 0; }
.viewport-meta, .schematic-tag { position: absolute; pointer-events: none; font-size: .73rem; color: #a9bfd3; }
.viewport-meta { top: 12px; left: 15px; }
.target-mark { color: var(--cyan); margin-right: 3px; }
.schematic-tag { bottom: 12px; right: 16px; }
.caption { min-height: 69px; display: flex; align-items: center; gap: 10px; padding: 9px 13px; }
.caption-icon { flex: 0 0 30px; display: grid; place-items: center; height: 30px; border-radius: 8px; color: var(--cyan); border: 1px solid #316273; background: #132f3d; font-size: 1.16rem; }
.caption .panel-label { color: var(--cyan); }
.caption p { font-size: .91rem; margin-top: 2px; }
.inspector { grid-area: inspector; display: flex; flex-direction: column; gap: 11px; padding: 13px; }
.inspector-heading { display: flex; align-items: center; justify-content: space-between; gap: 4px; }
.inspector h4 { font-size: 1.1rem; line-height: 1.35; margin-bottom: 5px; }
.inspector p { color: #becde0; font-size: .87rem; }
.task-card { border: 1px solid #2b5369; background: #11283a; border-radius: 9px; padding: 10px; }
.task-card .panel-label { color: var(--cyan); }
.task-card .prompt { margin: 4px 0 9px; color: var(--ink); font-weight: 650; line-height: 1.45; }
.choices { display: grid; gap: 6px; }
.choices.compact { grid-template-columns: repeat(4, minmax(0, 1fr)); }
.choice, .flow button {
  border: 1px solid #3a5971; border-radius: 6px; background: #152d40;
  padding: 7px 8px; min-height: 38px; text-align: left; font-size: .87rem;
}
.compact .choice { text-align: center; }
.choice:hover:not(:disabled), .flow button:hover { background: #214457; border-color: #6dcbd8; }
.choice[aria-pressed=true], .choice.correct { border-color: var(--mint); color: var(--mint); background: #17403f; }
.choice.incorrect { border-color: var(--warm); color: #ffd0c5; background: #3b2938; }
.choice:disabled:not(.correct) { opacity: .62; }
.task-card .task-note { color: var(--muted); font-size: .76rem; margin-top: 7px; }
.task-card .task-note:empty { display: none; }
.feedback { border-left: 2px solid var(--cyan); padding: 2px 0 2px 8px; }
.inspector .feedback[data-tone=good] { border-color: var(--mint); color: #b6f2df; }
.inspector .feedback[data-tone=retry] { border-color: var(--warm); color: #ffd1c3; }
.lesson-detail { display: grid; gap: 7px; }
.facts { margin: 0; display: grid; gap: 6px; font-size: .81rem; }
.facts div { display: grid; grid-template-columns: auto minmax(0, 1fr); gap: 8px; border-bottom: 1px solid #26374e; padding-bottom: 4px; }
.facts dt { color: var(--muted); }
.facts dd { margin: 0; text-align: right; overflow-wrap: anywhere; }
.lesson-detail details { font-size: .8rem; padding: 5px 7px; border: 1px solid var(--line); border-radius: 5px; }
.lesson-detail summary { cursor: pointer; color: var(--cyan); }
.lesson-detail details p { margin-top: 4px; font-size: inherit; }
.next-scene { margin-top: auto; display: flex; justify-content: space-between; align-items: center; gap: 6px; min-height: 38px; padding: 6px 10px; background: #1a3445; border: 1px solid #3a687b; border-radius: 7px; font-size: .86rem; color: #c9f7fc; }
.next-scene:hover { background: #244d61; }
.fold-control { width: 100%; accent-color: var(--cyan); margin: 2px 0; min-height: 24px; }
.fold-ends { display: flex; justify-content: space-between; color: var(--muted); font-size: .73rem; }
.flow { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 5px; }
.flow button { min-height: 33px; text-align: center; color: var(--cyan); }
.dock { grid-area: dock; display: grid; grid-template-columns: auto minmax(50px, 1fr) auto; align-items: center; gap: 17px; padding: 9px 12px; }
.transport { display: flex; gap: 6px; }
.icon-button, .play-button { display: inline-flex; justify-content: center; align-items: center; min-width: 36px; min-height: 38px; }
.icon-button { font-size: 1.38rem; line-height: 1; padding: 0 8px; }
.icon-button:disabled { color: #778ca3; opacity: .55; }
.play-button { gap: 6px; min-width: 76px; padding: 4px 8px; background: var(--cyan); border: 1px solid transparent; color: #0d2735; border-radius: 8px; font-weight: 750; font-size: .87rem; }
.play-button:hover { background: #a7f4fb; }
.play-button:disabled { background: #273e50; color: #c0d8e2; }
#play-icon { font-size: .81em; }
.scrub-heading { display: flex; justify-content: space-between; align-items: center; gap: 6px; font-size: .81rem; color: var(--muted); }
#frame-name { color: #c7e3ef; }
.clock { white-space: nowrap; }
.timeline { position: relative; line-height: 0; }
.timeline input { display: block; width: 100%; margin: 0; height: 19px; appearance: none; border-radius: 6px; background: transparent; cursor: pointer; }
.timeline input::-webkit-slider-runnable-track { height: 5px; border-radius: 5px; background: linear-gradient(90deg, var(--cyan) var(--progress, 0%), #30475e var(--progress, 0%)); }
.timeline input::-moz-range-track { height: 5px; border-radius: 5px; background: linear-gradient(90deg, var(--cyan) var(--progress, 0%), #30475e var(--progress, 0%)); }
.timeline input::-webkit-slider-thumb { appearance: none; width: 13px; height: 13px; margin-top: -4px; border-radius: 50%; background: var(--cyan); box-shadow: 0 0 7px #78e4ed60; }
.timeline input::-moz-range-thumb { width: 13px; height: 13px; border: 0; border-radius: 50%; background: var(--cyan); }
#frame-marks { position: absolute; pointer-events: none; inset: 6px 6px auto; }
#frame-marks i { position: absolute; height: 7px; width: 2px; border-radius: 2px; background: #a9c6d4; opacity: .75; }
#frame-marks i.gate-mark { background: var(--warm); }
.speed { display: flex; gap: 7px; align-items: center; color: var(--muted); font-size: .8rem; }
.speed select { min-height: 37px; padding: 0 7px; font-size: .87rem; }
.foot { display: flex; justify-content: space-between; gap: 8px; padding: 8px 2px; color: var(--subtle); font-size: .74rem; }

#art text { font-family: "Microsoft YaHei UI", "PingFang SC", system-ui, sans-serif; user-select: none; }
#art .mono { font-family: "Cascadia Mono", Consolas, monospace; }
#art [data-action] { cursor: pointer; outline: none; }
#art [data-action]:is(:hover, :focus-visible) .hit-outline { stroke: #fff; stroke-width: 3; }
.large-type { font-size: 18px; }
.large-type #art .diagram-label { font-size: 19px; }
.large-type #art .diagram-small { font-size: 15px; }
.fullscreen-fallback .masthead { position: sticky; top: 0; z-index: 3; }
.fullscreen-fallback .lesson-head, .fullscreen-fallback .foot { display: none; }
.fullscreen-fallback .workspace { margin-top: 9px; }

@media (max-width: 1020px) {
  .shell { padding-inline: 14px; }
  .masthead { padding-inline: 14px; }
  .workspace { grid-template-columns: minmax(0, 1fr) minmax(230px, .42fr); grid-template-areas: "nav nav" "scene inspector" "dock dock"; gap: 9px; }
  .rail { padding: 5px 7px; }
  .rail-head, .rail-note, .step small { display: none; }
  .steps { display: flex; gap: 3px; overflow-x: auto; scrollbar-width: thin; padding: 3px; }
  .steps li { flex: 1 0 auto; }
  .step { min-height: 38px; padding: 4px 6px; gap: 5px; }
  .step-index { flex-basis: 23px; width: 23px; height: 23px; }
  .step[aria-current=step] { box-shadow: inset 0 -2px var(--cyan); }
}
@media (max-width: 680px) {
  .shell { padding-inline: 9px; }
  .masthead { padding: 7px 9px; min-height: 55px; }
  .brand, .header-tools { gap: 5px; }
  .brand-mark { width: 32px; height: 32px; }
  .brand h1 { font-size: .94rem; letter-spacing: .02em; }
  .brand p { font-size: .57rem; }
  .local-status { display: none; }
  .tool-button { min-height: 38px; padding-inline: 6px; font-size: .77rem; }
  .lesson-head { align-items: flex-start; flex-wrap: wrap; gap: 6px; padding: 10px 1px; }
  .lesson-head h2 { font-size: 1.52rem; }
  .journey { gap: 4px; align-self: end; margin: 0; }
  .journey span { padding: 2px 5px; }
  .workspace { grid-template-columns: minmax(0, 1fr); grid-template-areas: "nav" "scene" "dock" "inspector"; gap: 8px; }
  .scene-heading { padding: 8px; }
  .model-chip { font-size: .67rem; padding-inline: 4px; }
  .viewport { min-height: clamp(218px, 65vw, 405px); }
  #art .diagram-label { font-size: 19px; }
  #art .mono[font-size="11"] { font-size: 13px; }
  #art .mono[font-size="16"] { font-size: 20px; }
  .viewport-meta { top: 9px; left: 10px; }
  .schematic-tag { bottom: 8px; right: 9px; }
  .caption { padding: 7px; min-height: 60px; gap: 6px; }
  .caption p { font-size: .86rem; }
  .dock { grid-template-columns: minmax(0, 1fr) auto; grid-template-areas: "transport speed" "scrub scrub"; gap: 4px 7px; padding: 7px; }
  .transport { grid-area: transport; }
  .scrub { grid-area: scrub; }
  .speed { grid-area: speed; }
  .speed span { display: none; }
  .steps button, .icon-button, .play-button, .speed select, .choice, .flow button, .next-scene { min-height: 44px; }
  .inspector { padding: 9px; }
  .large-type .brand p { display: none; }
}

/* ─── 3D 模块样式 ──────────────────────────────── */

/* 3D 工具栏 */
.toolbar3d {
  position: absolute; top: 12px; right: 16px; z-index: 2;
  display: flex; gap: 4px; align-items: center;
  background: #111c2daa; backdrop-filter: blur(8px);
  border: 1px solid #26374e; border-radius: 9px; padding: 4px 6px;
}
.toolbar3d-btn {
  width: 30px; height: 30px; display: grid; place-items: center;
  border: 1px solid transparent; border-radius: 6px;
  background: transparent; color: var(--muted); font-size: 1.05rem;
  cursor: pointer; line-height: 1; padding: 0;
}
.toolbar3d-btn:hover { background: #203749; color: var(--cyan); border-color: #4a8090; }
.toolbar3d-btn.active, .toolbar3d-btn[aria-pressed=true] { color: var(--cyan); background: #153348; border-color: #2f687d; }
.toolbar3d-sep { width: 1px; height: 18px; background: #33455c; margin-inline: 2px; }

/* 透明度滑块 */
.opacity3d {
  position: absolute; bottom: 44px; right: 16px; z-index: 2;
  display: flex; gap: 8px; align-items: center;
  background: #111c2daa; backdrop-filter: blur(8px);
  border: 1px solid #26374e; border-radius: 9px; padding: 6px 10px;
  font-size: .77rem; color: var(--muted);
}
.opacity3d input {
  width: 80px; height: 6px; appearance: none; border-radius: 3px;
  background: linear-gradient(90deg, var(--cyan) var(--progress, 0%), #30475e var(--progress, 0%));
  cursor: pointer; accent-color: var(--cyan);
}
.opacity3d input::-webkit-slider-thumb { appearance: none; width: 14px; height: 14px; border-radius: 50%; background: var(--cyan); }

/* 加载状态 */
.model3d-message {
  position: absolute; inset: 0; z-index: 5;
  display: grid; place-items: center;
  background: #0b1220cc; color: var(--cyan);
  font-size: 1.2rem; font-weight: 650; letter-spacing: .04em;
}
.model3d-message.error { color: var(--warm); }

.model3d-progress {
  position: absolute; bottom: 50%; left: 10%; right: 10%; z-index: 6;
  height: 6px; border-radius: 3px; background: #26374e;
}
.model3d-progress-bar {
  height: 100%; border-radius: 3px; background: var(--cyan);
  width: var(--progress, 0%); transition: width .2s;
  box-shadow: 0 0 10px #78e4ed50;
}

/* 3D 标注 */
.model3d-label, .model3d-label:is(.auto-label) {
  color: var(--ink); font-size: 13px; font-weight: 650;
  background: #0b1220cc; border: 1px solid var(--cyan);
  border-radius: 5px; padding: 3px 8px; white-space: nowrap;
  pointer-events: auto; cursor: pointer;
  text-shadow: 0 0 4px #000;
  letter-spacing: .03em;
}
.model3d-label:hover { background: #153348; border-color: #fff; }
.auto-label { border-color: var(--muted); opacity: .8; font-size: 11px; }
.auto-label:hover { opacity: 1; border-color: var(--cyan); }
.large-type .model3d-label { font-size: 17px; }
.large-type .auto-label { font-size: 14px; }

/* 模型选择器 */
.model-selector {
  display: grid; gap: 6px;
  padding: 8px 0; border-top: 1px solid var(--line);
}
.model-selector select {
  background: #152238; color: var(--ink); border: 1px solid #33455c;
  border-radius: 6px; padding: 6px 8px; font-size: .87rem; min-height: 36px;
}
.model-selector select:hover { border-color: #4a8090; }

/* 模型库 */
.model-library {
  position: absolute; inset: 0; z-index: 10;
  background: #0f1828f2; backdrop-filter: blur(12px);
  padding: 16px; display: flex; flex-direction: column; gap: 12px;
  overflow-y: auto;
}
.model-library[hidden] { display: none !important; }
.library-head {
  display: flex; justify-content: space-between; align-items: center;
  position: sticky; top: 0; z-index: 1;
  background: inherit; padding-bottom: 8px;
}
.library-head .icon-button { min-width: 36px; min-height: 36px; font-size: 1.5rem; }
.model-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 10px;
}
.model-card {
  display: flex; align-items: center; gap: 10px;
  min-height: 52px; padding: 8px 12px;
  border: 1px solid #33455c; border-radius: 8px;
  background: #152238; color: var(--ink);
  text-align: left; font-size: .86rem; cursor: pointer;
  transition: background .15s, border-color .15s;
}
.model-card:hover { background: #203749; border-color: var(--cyan); }
.model-card-index {
  flex: 0 0 28px; width: 28px; height: 28px; display: grid; place-items: center;
  border-radius: 50%; background: #1a3345; border: 1px solid #3c526c;
  font: 700 .73rem Consolas, monospace; color: var(--cyan);
}
.model-card-name { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.library-note { color: var(--muted); font-size: .76rem; text-align: center; margin: 0; }

/* 模型库入口按钮 */
.model-library-btn {
  display: flex; align-items: center; gap: 8px; width: 100%;
  min-height: 42px; padding: 6px 10px; margin-top: auto;
  border: 1px solid #3a687b; border-radius: 7px;
  background: #1a3445; color: #c9f7fc;
  font-size: .84rem; cursor: pointer;
}
.model-library-btn:hover { background: #244d61; }

/* WebGL 警告 */
.webgl-warning {
  position: fixed; bottom: 16px; right: 16px; z-index: 20;
  max-width: 320px; padding: 12px 16px;
  background: #31232f; border: 1px solid var(--warm);
  border-radius: 9px; color: #ffd1c3; font-size: .84rem;
}

/* 3D 模式下 dock 状态提示 */
.dock[data-mode="3d"] .scrub-heading { opacity: .45; }
.dock[data-mode="3d"] .timeline input { pointer-events: none; opacity: .4; }
.dock[data-mode="3d"] #play { opacity: .35; pointer-events: none; }

/* 响应式覆盖 */
@media (max-width: 680px) {
  .toolbar3d { top: 8px; right: 8px; gap: 2px; padding: 3px 4px; }
  .toolbar3d-btn { width: 26px; height: 26px; font-size: .95rem; }
  .opacity3d { bottom: 36px; right: 8px; }
  .opacity3d span { display: none; }
  .opacity3d input { width: 64px; }
  .model-grid { grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); }
  .model-card { min-height: 44px; padding: 6px 8px; font-size: .78rem; }
}