@import url('https://fonts.googleapis.com/css2?family=Noto+Serif+SC:wght@400;500;700&family=JetBrains+Mono:wght@400;500&family=Inter:wght@300;400;500&display=swap');

:root {
  --bg: #0d0f11;
  --bg2: #13161a;
  --bg3: #1a1e24;
  --border: rgba(255,255,255,0.07);
  --border2: rgba(255,255,255,0.12);
  --text: #e8e6e0;
  --text2: #9a9690;
  --text3: #5c5a56;
  --accent: #4ade9a;
  --accent2: #2ec4b6;
  --accent3: #ff6b6b;
  --amber: #f59e0b;
  --blue: #60a5fa;
  --purple: #a78bfa;
  --font-serif: 'Noto Serif SC', serif;
  --font-sans: 'Inter', sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
  --radius: 8px;
  --radius-lg: 14px;
  --nav-bg: rgba(13,15,17,0.85);
}

/* ── Light theme override ── */
:root[data-theme="light"] {
  --bg: #faf9f6;
  --bg2: #ffffff;
  --bg3: #f0ede6;
  --border: rgba(0,0,0,0.08);
  --border2: rgba(0,0,0,0.16);
  --text: #1a1814;
  --text2: #4a4640;
  --text3: #8a857c;
  --accent: #16a34a;
  --accent2: #0d9488;
  --accent3: #dc2626;
  --amber: #d97706;
  --blue: #2563eb;
  --purple: #7c3aed;
  --nav-bg: rgba(250,249,246,0.85);
}

/* ── Theme toggle button ── */
.theme-toggle {
  background: transparent; border: 1px solid var(--border2);
  color: var(--text2); cursor: pointer;
  width: 30px; height: 30px; border-radius: 6px;
  display: inline-flex; align-items: center; justify-content: center;
  font-size: 14px; padding: 0; line-height: 1;
  transition: color 0.2s, border-color 0.2s;
}
.theme-toggle:hover { color: var(--text); border-color: var(--text2); }
:root[data-theme="light"] .theme-toggle .icon-sun { display: none; }
:root[data-theme="light"] .theme-toggle .icon-moon { display: inline; }
.theme-toggle .icon-sun { display: inline; }
.theme-toggle .icon-moon { display: none; }

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { font-size: 16px; scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  line-height: 1.7;
  min-height: 100vh;
}

/* ── Scrollbar ── */
::-webkit-scrollbar { width: 5px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--border2); border-radius: 3px; }

/* ── Nav ── */
.nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 32px; height: 56px;
  background: var(--nav-bg);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
}
.nav-logo {
  font-family: var(--font-mono); font-size: 13px; color: var(--accent);
  text-decoration: none; letter-spacing: 0.05em;
}
.nav-links { display: flex; gap: 28px; }
.nav-links a {
  font-size: 13px; color: var(--text2); text-decoration: none;
  transition: color 0.2s;
}
.nav-links a:hover { color: var(--text); }

/* ── Page wrapper ── */
.page { padding-top: 56px; }

/* ── Hero (index) ── */
.hero {
  padding: 80px 32px 60px;
  max-width: 860px; margin: 0 auto;
  border-bottom: 1px solid var(--border);
}
.hero-tag {
  font-family: var(--font-mono); font-size: 11px; color: var(--accent);
  letter-spacing: 0.12em; text-transform: uppercase;
  margin-bottom: 20px;
}
.hero h1 {
  font-family: var(--font-serif); font-size: clamp(28px, 5vw, 46px);
  font-weight: 700; line-height: 1.25;
  color: var(--text); margin-bottom: 16px;
}
.hero p {
  font-size: 15px; color: var(--text2); max-width: 600px; line-height: 1.8;
}

/* ── Paper grid ── */
.papers-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1px; background: var(--border);
  border-top: 1px solid var(--border); border-bottom: 1px solid var(--border);
}
.paper-card {
  background: var(--bg); padding: 28px;
  text-decoration: none; color: inherit;
  display: flex; flex-direction: column; gap: 12px;
  transition: background 0.15s;
  position: relative; overflow: hidden;
}
.paper-card::before {
  content: ''; position: absolute; top: 0; left: 0; right: 0;
  height: 2px; background: var(--accent); transform: scaleX(0);
  transform-origin: left; transition: transform 0.25s;
}
.paper-card:hover { background: var(--bg2); }
.paper-card:hover::before { transform: scaleX(1); }

.card-tag {
  font-family: var(--font-mono); font-size: 10px; letter-spacing: 0.1em;
  text-transform: uppercase; color: var(--text3);
}
.card-title {
  font-family: var(--font-serif); font-size: 17px; font-weight: 500;
  color: var(--text); line-height: 1.4;
}
.card-subtitle { font-size: 13px; color: var(--text2); line-height: 1.6; }
.card-meta {
  display: flex; gap: 12px; flex-wrap: wrap; margin-top: auto; padding-top: 8px;
}
.card-pill {
  font-family: var(--font-mono); font-size: 10px;
  padding: 3px 8px; border-radius: 3px;
  background: var(--bg3); color: var(--text3);
  border: 1px solid var(--border);
}

/* ── Paper page layout ── */
.paper-page {
  max-width: 780px; margin: 0 auto;
  padding: 60px 32px 120px;
}

.paper-header {
  padding-bottom: 40px; margin-bottom: 40px;
  border-bottom: 1px solid var(--border);
}
.paper-venue {
  font-family: var(--font-mono); font-size: 11px; color: var(--accent);
  letter-spacing: 0.1em; text-transform: uppercase; margin-bottom: 16px;
}
.paper-title {
  font-family: var(--font-serif); font-size: clamp(22px, 4vw, 34px);
  font-weight: 700; line-height: 1.3; color: var(--text);
  margin-bottom: 14px;
}
.paper-authors {
  font-size: 13px; color: var(--text2); margin-bottom: 20px;
}
.paper-badges { display: flex; gap: 8px; flex-wrap: wrap; }
.badge {
  font-family: var(--font-mono); font-size: 11px;
  padding: 4px 10px; border-radius: 4px;
  border: 1px solid var(--border2); color: var(--text2);
}
.badge-green { border-color: rgba(74,222,154,0.3); color: var(--accent); }
.badge-blue { border-color: rgba(96,165,250,0.3); color: var(--blue); }
.badge-amber { border-color: rgba(245,158,11,0.3); color: var(--amber); }

/* ── Table of contents ── */
.toc {
  background: var(--bg2); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 20px 24px;
  margin-bottom: 48px;
}
.toc-title {
  font-family: var(--font-mono); font-size: 11px; color: var(--text3);
  letter-spacing: 0.1em; text-transform: uppercase; margin-bottom: 12px;
}
.toc ol { padding-left: 20px; }
.toc li { margin: 6px 0; }
.toc a { font-size: 13px; color: var(--text2); text-decoration: none; transition: color 0.15s; }
.toc a:hover { color: var(--accent); }

/* ── Content sections ── */
.section { margin-bottom: 56px; }
.section-num {
  font-family: var(--font-mono); font-size: 11px; color: var(--text3);
  letter-spacing: 0.08em; margin-bottom: 6px;
}
.section h2 {
  font-family: var(--font-serif); font-size: 22px; font-weight: 700;
  color: var(--text); margin-bottom: 20px; line-height: 1.35;
}
.section h3 {
  font-family: var(--font-serif); font-size: 16px; font-weight: 500;
  color: var(--text); margin: 28px 0 12px;
}
.section p { font-size: 15px; color: var(--text2); line-height: 1.85; margin-bottom: 14px; }
.section p strong { color: var(--text); font-weight: 500; }

/* ── Callout boxes ── */
.callout {
  border-left: 3px solid var(--accent);
  background: rgba(74,222,154,0.04);
  padding: 14px 18px; border-radius: 0 var(--radius) var(--radius) 0;
  margin: 20px 0;
}
.callout.amber { border-color: var(--amber); background: rgba(245,158,11,0.04); }
.callout.red { border-color: var(--accent3); background: rgba(255,107,107,0.04); }
.callout.blue { border-color: var(--blue); background: rgba(96,165,250,0.04); }
.callout.purple { border-color: var(--purple); background: rgba(167,139,250,0.04); }

.callout-label {
  font-family: var(--font-mono); font-size: 10px; letter-spacing: 0.1em;
  text-transform: uppercase; color: var(--accent); margin-bottom: 6px;
}
.callout.amber .callout-label { color: var(--amber); }
.callout.red .callout-label { color: var(--accent3); }
.callout.blue .callout-label { color: var(--blue); }
.callout.purple .callout-label { color: var(--purple); }
.callout p { margin: 0; font-size: 14px; }

/* ── Key-value table ── */
.kv-table { width: 100%; border-collapse: collapse; margin: 16px 0; }
.kv-table tr { border-bottom: 1px solid var(--border); }
.kv-table tr:last-child { border-bottom: none; }
.kv-table td { padding: 10px 4px; font-size: 14px; vertical-align: top; }
.kv-table td:first-child {
  color: var(--text3); font-family: var(--font-mono); font-size: 12px;
  width: 160px; padding-right: 16px; white-space: nowrap;
}
.kv-table td:last-child { color: var(--text2); }

/* ── Code ── */
code {
  font-family: var(--font-mono); font-size: 12px;
  background: var(--bg3); color: var(--accent);
  padding: 2px 6px; border-radius: 4px;
  border: 1px solid var(--border);
}
.code-block {
  background: var(--bg2); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 18px 20px; margin: 16px 0;
  overflow-x: auto;
}
.code-block code {
  background: none; border: none; padding: 0;
  font-size: 13px; color: var(--text2); display: block; line-height: 1.7;
}

/* ── Diagram container ── */
.diagram-wrap {
  background: var(--bg2); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 24px;
  margin: 24px 0; overflow-x: auto;
}
.diagram-caption {
  font-size: 12px; color: var(--text3); text-align: center;
  margin-top: 12px; font-family: var(--font-mono);
}

/* ── Module cards (for architecture breakdowns) ── */
.module-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin: 20px 0; }
@media (max-width: 600px) { .module-grid { grid-template-columns: 1fr; } }
.module-card {
  background: var(--bg2); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 16px;
}
.module-card-name {
  font-family: var(--font-mono); font-size: 11px; letter-spacing: 0.08em;
  color: var(--accent); margin-bottom: 4px;
}
.module-card-title { font-size: 14px; font-weight: 500; color: var(--text); margin-bottom: 6px; }
.module-card-desc { font-size: 13px; color: var(--text2); line-height: 1.6; }

/* ── Footer ── */
.footer {
  border-top: 1px solid var(--border);
  padding: 32px; text-align: center;
  font-size: 12px; color: var(--text3); font-family: var(--font-mono);
}
.footer a { color: var(--text3); text-decoration: none; }
.footer a:hover { color: var(--text2); }

/* ── Back link ── */
.back-link {
  display: inline-flex; align-items: center; gap: 6px;
  font-family: var(--font-mono); font-size: 12px; color: var(--text3);
  text-decoration: none; margin-bottom: 36px;
  transition: color 0.15s;
}
.back-link:hover { color: var(--text2); }

/* ── Responsive ── */
@media (max-width: 640px) {
  .nav { padding: 0 20px; }
  .hero { padding: 60px 20px 40px; }
  .paper-page { padding: 40px 20px 80px; }
  .papers-grid { grid-template-columns: 1fr; }
  .module-grid { grid-template-columns: 1fr; }
}

/* ═══════════════════════════════════════════════════════════
   Docs Layout · 三栏文档式布局
   左：章节树 / 中：正文 / 右：本节目录
   ═══════════════════════════════════════════════════════════ */

.docs-layout {
  display: grid;
  grid-template-columns: 240px minmax(0, 1fr);
  max-width: 1280px; margin: 0 auto;
  min-height: calc(100vh - 56px);
}
.docs-layout.has-right { grid-template-columns: 240px minmax(0, 1fr) 220px; max-width: 1400px; }

.docs-sidebar-left, .docs-sidebar-right {
  position: sticky; top: 56px;
  height: calc(100vh - 56px); overflow-y: auto;
  padding: 28px 0; font-size: 13px;
}

.docs-sidebar-left {
  border-right: 1px solid var(--border);
  padding-left: 24px; padding-right: 12px;
}
.docs-sidebar-right {
  border-left: 1px solid var(--border);
  padding-left: 24px; padding-right: 24px;
}

.docs-sidebar-left .ds-title {
  font-family: var(--font-mono); font-size: 11px; color: var(--text3);
  letter-spacing: 0.1em; text-transform: uppercase; margin-bottom: 14px;
  padding: 0 10px;
}
.docs-sidebar-left details { margin-bottom: 2px; }
.docs-sidebar-left summary {
  cursor: pointer; padding: 6px 10px; border-radius: 4px;
  color: var(--text2); list-style: none;
  font-family: var(--font-mono); font-size: 12px;
  display: flex; align-items: center; gap: 6px;
}
.docs-sidebar-left summary::-webkit-details-marker { display: none; }
.docs-sidebar-left summary::before {
  content: '▸'; font-size: 9px; color: var(--text3);
  transition: transform 0.15s;
}
.docs-sidebar-left details[open] > summary::before { transform: rotate(90deg); }
.docs-sidebar-left summary:hover { color: var(--text); background: var(--bg2); }
.docs-sidebar-left .ds-leaf {
  display: block; padding: 5px 10px 5px 26px;
  color: var(--text2); text-decoration: none;
  border-radius: 4px; font-size: 12.5px;
}
.docs-sidebar-left .ds-leaf:hover { color: var(--text); background: var(--bg2); }
.docs-sidebar-left .ds-leaf.active {
  color: var(--accent); background: var(--bg2);
  border-left: 2px solid var(--accent); padding-left: 24px;
}
.docs-sidebar-left a.ds-leaf-top {
  display: block; padding: 6px 10px;
  color: var(--text2); text-decoration: none;
  font-family: var(--font-mono); font-size: 12px;
  border-radius: 4px;
}
.docs-sidebar-left a.ds-leaf-top:hover { color: var(--text); background: var(--bg2); }
.docs-sidebar-left a.ds-leaf-top.active { color: var(--accent); background: var(--bg2); }

.docs-sidebar-right .ds-title {
  font-family: var(--font-mono); font-size: 11px; color: var(--text3);
  letter-spacing: 0.1em; text-transform: uppercase; margin-bottom: 14px;
}
.docs-sidebar-right ul { list-style: none; padding: 0; }
.docs-sidebar-right li { margin: 6px 0; }
.docs-sidebar-right a {
  color: var(--text2); text-decoration: none; font-size: 12.5px;
  padding-left: 10px; border-left: 2px solid var(--border);
  display: block; transition: color 0.15s, border-color 0.15s;
}
.docs-sidebar-right a:hover,
.docs-sidebar-right a.active { color: var(--accent); border-left-color: var(--accent); }
.docs-sidebar-right a.toc-h3 { padding-left: 22px; font-size: 12px; color: var(--text3); }

.docs-content {
  padding: 40px 56px 120px;
  max-width: 820px; margin: 0 auto; width: 100%;
}
.docs-content h1 {
  font-family: var(--font-serif); font-size: 32px; font-weight: 700;
  color: var(--text); margin: 0 0 24px; line-height: 1.3;
}
.docs-content h2 {
  font-family: var(--font-serif); font-size: 24px; font-weight: 700;
  color: var(--text); margin: 56px 0 16px; line-height: 1.35;
  padding-top: 16px; border-top: 1px solid var(--border);
}
.docs-content h3 {
  font-family: var(--font-serif); font-size: 18px; font-weight: 700;
  color: var(--text); margin: 36px 0 12px;
}
.docs-content h4 {
  font-family: var(--font-sans); font-size: 14px; font-weight: 600;
  color: var(--text2); margin: 24px 0 10px;
  text-transform: uppercase; letter-spacing: 0.05em;
}
.docs-content p { font-size: 15px; line-height: 1.85; color: var(--text2); margin-bottom: 14px; }
.docs-content p strong { color: var(--text); font-weight: 600; }
.docs-content ul, .docs-content ol { margin: 12px 0 18px 24px; color: var(--text2); }
.docs-content li { font-size: 15px; line-height: 1.85; margin-bottom: 6px; }

.docs-breadcrumb {
  font-family: var(--font-mono); font-size: 12px; color: var(--text3);
  margin-bottom: 20px;
}
.docs-breadcrumb a { color: var(--text3); text-decoration: none; }
.docs-breadcrumb a:hover { color: var(--text2); }
.docs-breadcrumb span.sep { margin: 0 8px; }

/* ── 中文导读块 ── */
.cn-read {
  background: var(--bg2);
  border-left: 3px solid var(--accent);
  padding: 18px 22px; margin: 18px 0;
  border-radius: 0 6px 6px 0;
}
.cn-read .cn-label {
  font-family: var(--font-mono); font-size: 10px; color: var(--accent);
  letter-spacing: 0.1em; text-transform: uppercase; margin-bottom: 10px;
}
.cn-read p { color: var(--text); font-size: 15px; }
.cn-read p:last-child { margin-bottom: 0; }

/* ── 原文引用（折叠） ── */
.en-quote {
  margin: 14px 0; border: 1px solid var(--border);
  border-radius: 6px; background: var(--bg2);
}
.en-quote summary {
  cursor: pointer; padding: 10px 16px;
  font-family: var(--font-mono); font-size: 11px; color: var(--text3);
  letter-spacing: 0.06em; list-style: none;
  display: flex; align-items: center; gap: 8px;
}
.en-quote summary::-webkit-details-marker { display: none; }
.en-quote summary::before {
  content: '▸'; font-size: 9px; transition: transform 0.15s;
}
.en-quote[open] summary::before { transform: rotate(90deg); }
.en-quote summary:hover { color: var(--text2); }
.en-quote .quote-body {
  padding: 0 18px 16px; border-top: 1px solid var(--border);
  margin-top: 8px; padding-top: 14px;
  font-family: 'Charter', 'Georgia', serif; font-style: italic;
  font-size: 13.5px; color: var(--text2); line-height: 1.75;
}
.en-quote .quote-body p { font-size: 13.5px; color: var(--text2); }
.en-quote .quote-cite {
  font-family: var(--font-mono); font-style: normal;
  font-size: 10px; color: var(--text3); margin-top: 8px;
}

/* ── 原图嵌入 ── */
.fig-block {
  margin: 24px 0; padding: 16px;
  background: var(--bg2); border: 1px solid var(--border);
  border-radius: 8px;
}
:root[data-theme="light"] .fig-block { background: #fff; }
.fig-block img {
  width: 100%; max-width: 700px; display: block; margin: 0 auto;
  border-radius: 4px;
  background: white;
}
.fig-block .fig-cap {
  margin-top: 12px; padding-top: 10px;
  border-top: 1px dashed var(--border);
  font-size: 12.5px; color: var(--text3); line-height: 1.65;
}
.fig-block .fig-cap .fig-num {
  font-family: var(--font-mono); color: var(--accent); margin-right: 8px;
}
.fig-block .fig-cap .fig-cn {
  display: block; margin-top: 6px; color: var(--text2);
}

/* ── 术语对照（hover 出英文）── */
.term {
  border-bottom: 1px dotted var(--accent);
  cursor: help; position: relative;
  color: var(--text);
}
.term::after {
  content: attr(data-en);
  position: absolute; bottom: 100%; left: 50%; transform: translateX(-50%);
  background: var(--bg3); color: var(--accent);
  font-family: var(--font-mono); font-size: 11px;
  padding: 4px 8px; border-radius: 4px;
  border: 1px solid var(--border2);
  white-space: nowrap; pointer-events: none;
  opacity: 0; transition: opacity 0.15s;
  margin-bottom: 4px;
}
.term:hover::after { opacity: 1; }

/* ── 互动卡片切换 ── */
.tab-switcher { margin: 22px 0; }
.tab-switcher .tabs {
  display: flex; gap: 0; border-bottom: 1px solid var(--border);
}
.tab-switcher .tab {
  padding: 10px 16px; font-family: var(--font-mono); font-size: 12px;
  color: var(--text3); cursor: pointer; user-select: none;
  border-bottom: 2px solid transparent; margin-bottom: -1px;
  transition: color 0.15s, border-color 0.15s;
}
.tab-switcher .tab:hover { color: var(--text2); }
.tab-switcher .tab.active { color: var(--accent); border-bottom-color: var(--accent); }
.tab-switcher .panel { display: none; padding: 18px 0; }
.tab-switcher .panel.active { display: block; }

/* ── 移动端 ── */
@media (max-width: 1100px) {
  .docs-layout { grid-template-columns: 220px minmax(0, 1fr); }
  .docs-sidebar-right { display: none; }
  .docs-content { padding: 32px 32px 80px; }
}
@media (max-width: 760px) {
  .docs-layout { grid-template-columns: 1fr; }
  .docs-sidebar-left {
    position: relative; top: 0; height: auto; max-height: 60vh;
    border-right: none; border-bottom: 1px solid var(--border);
  }
  .docs-content { padding: 28px 20px 60px; }
}

/* ── 图后讲解块 ── */
.fig-explain {
  margin: 14px 0 24px;
  padding: 16px 20px;
  background: var(--bg2);
  border: 1px solid var(--border);
  border-left: 3px solid var(--blue);
  border-radius: 0 6px 6px 0;
}
.fig-explain .fe-label {
  font-family: var(--font-mono); font-size: 10px; color: var(--blue);
  letter-spacing: 0.1em; text-transform: uppercase; margin-bottom: 10px;
}
.fig-explain p { font-size: 14px; color: var(--text); margin-bottom: 8px; line-height: 1.8; }
.fig-explain p:last-child { margin-bottom: 0; }
.fig-explain ol, .fig-explain ul { margin: 8px 0 8px 22px; }
.fig-explain li { font-size: 14px; color: var(--text); line-height: 1.8; margin-bottom: 4px; }
.fig-explain code {
  background: var(--bg3); padding: 1px 5px; border-radius: 3px;
  font-family: var(--font-mono); font-size: 12px; color: var(--accent);
}

/* ═══ 交互组件 ═══ */

/* ── Step Walker ── */
.step-walker {
  margin: 22px 0;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--bg2);
  overflow: hidden;
}
.step-walker .sw-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 12px 18px; background: var(--bg3);
  border-bottom: 1px solid var(--border);
}
.step-walker .sw-title {
  font-family: var(--font-mono); font-size: 12px; color: var(--accent);
  letter-spacing: 0.06em;
}
.step-walker .sw-controls { display: flex; align-items: center; gap: 12px; }
.step-walker .sw-btn {
  background: transparent; border: 1px solid var(--border2);
  color: var(--text2); cursor: pointer;
  width: 28px; height: 28px; border-radius: 4px;
  font-size: 14px; line-height: 1;
  display: inline-flex; align-items: center; justify-content: center;
  transition: all 0.15s;
}
.step-walker .sw-btn:hover:not(:disabled) { color: var(--accent); border-color: var(--accent); }
.step-walker .sw-btn:disabled { opacity: 0.3; cursor: not-allowed; }
.step-walker .sw-counter {
  font-family: var(--font-mono); font-size: 12px; color: var(--text3);
  min-width: 40px; text-align: center;
}
.step-walker .sw-progress {
  display: flex; gap: 4px; padding: 10px 18px 0;
}
.step-walker .sw-dot {
  flex: 1; height: 3px; background: var(--border);
  border-radius: 2px; transition: background 0.2s;
  cursor: pointer;
}
.step-walker .sw-dot.done { background: var(--accent); opacity: 0.4; }
.step-walker .sw-dot.active { background: var(--accent); }
.step-walker .sw-body { padding: 18px; min-height: 100px; }
.step-walker .sw-step { display: none; }
.step-walker .sw-step.active { display: block; animation: fadeIn 0.25s; }
.step-walker .sw-step h4 {
  font-family: var(--font-serif); font-size: 16px; color: var(--text);
  margin: 0 0 10px; text-transform: none; letter-spacing: 0;
}
.step-walker .sw-step p { font-size: 14px; color: var(--text); line-height: 1.8; margin-bottom: 8px; }
.step-walker .sw-step code {
  background: var(--bg3); padding: 1px 5px; border-radius: 3px;
  font-family: var(--font-mono); font-size: 12px; color: var(--accent);
}
@keyframes fadeIn { from { opacity: 0; transform: translateY(4px); } to { opacity: 1; transform: translateY(0); } }

/* ── Image Hotspot ── */
.hotspot-wrap {
  position: relative; display: block; width: 100%; max-width: 700px;
  margin: 0 auto;
}
.hotspot-wrap img { width: 100%; display: block; border-radius: 4px; background: white; }
.hotspot {
  position: absolute; width: 20px; height: 20px;
  background: var(--accent); color: var(--bg);
  border-radius: 50%; cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  font-family: var(--font-mono); font-size: 11px; font-weight: 700;
  border: 1.5px solid rgba(255,255,255,0.9);
  box-shadow: 0 1px 4px rgba(0,0,0,0.4);
  transform: translate(-50%, -50%);
  transition: opacity .15s, transform .15s, background .15s;
  z-index: 2;
  opacity: 0.55;
}
.hotspot-wrap:hover .hotspot { opacity: 0.85; }
.hotspot:hover { opacity: 1 !important; transform: translate(-50%, -50%) scale(1.25); }
.hotspot.active {
  opacity: 1 !important;
  background: var(--amber);
  box-shadow: 0 0 0 3px rgba(245,158,11,0.35), 0 1px 4px rgba(0,0,0,0.4);
  animation: hs-ping 1.2s ease-out 1;
}
@keyframes hs-ping {
  0%   { box-shadow: 0 0 0 0   rgba(245,158,11,0.6), 0 1px 4px rgba(0,0,0,0.4); }
  100% { box-shadow: 0 0 0 14px rgba(245,158,11,0),   0 1px 4px rgba(0,0,0,0.4); }
}
.hotspot-panel {
  margin-top: 14px; padding: 14px 18px;
  background: var(--bg3); border: 1px solid var(--border);
  border-left: 3px solid var(--amber);
  border-radius: 0 6px 6px 0;
  font-size: 14px; color: var(--text); line-height: 1.75;
  min-height: 60px;
}

/* ── Fig + hotspot 侧边布局（宽屏图在左、面板粘右）── */
.fig-interactive {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 260px;
  gap: 16px; align-items: start;
  margin: 24px 0;
}
.fig-interactive > .fig-block { margin: 0; }
.fig-interactive > .hotspot-panel {
  margin-top: 0; position: sticky; top: 80px;
  max-height: calc(100vh - 120px); overflow-y: auto;
}
@media (max-width: 1200px) {
  .fig-interactive { grid-template-columns: 1fr; gap: 0; }
  .fig-interactive > .hotspot-panel { position: static; max-height: none; margin-top: 14px; }
}

/* ── Hotspot dev mode (?edit-hotspots=1) ── */
.hotspot-wrap.edit-mode { cursor: crosshair; }
.hotspot-wrap.edit-mode .hotspot {
  opacity: 0.9; cursor: grab;
  background: #ff3b6b; color: #fff; font-weight: 700;
  outline: 2px solid #fff; box-shadow: 0 0 0 2px #ff3b6b;
}
.hotspot-wrap.edit-mode .hotspot.dragging { cursor: grabbing; z-index: 20; transform: translate(-50%, -50%) scale(1.3); }
.hs-edit-marker {
  position: absolute; width: 14px; height: 14px;
  background: #ff3b6b; border: 2px solid #fff; border-radius: 50%;
  transform: translate(-50%, -50%); pointer-events: none; z-index: 10;
  box-shadow: 0 0 0 2px #ff3b6b, 0 2px 8px rgba(0,0,0,0.4);
}
.hs-edit-toast {
  position: fixed; top: 72px; right: 16px; z-index: 999;
  background: #111; color: #f5f5f5; border: 1px solid #ff3b6b;
  padding: 10px 14px; border-radius: 6px;
  font-family: var(--font-mono); font-size: 12px; line-height: 1.6;
  box-shadow: 0 8px 24px rgba(0,0,0,0.5); max-width: 320px;
}
.hs-edit-toast b { color: #ff6b8a; }

/* 汇总导出面板 */
.hs-edit-panel {
  position: fixed; bottom: 16px; right: 16px; z-index: 999;
  width: 380px; max-height: 60vh; display: flex; flex-direction: column;
  background: #0f1114; color: #e8e6e0; border: 1px solid #ff3b6b;
  border-radius: 8px; font-family: var(--font-mono); font-size: 11px;
  box-shadow: 0 8px 32px rgba(0,0,0,0.6);
}
.hs-edit-panel-head {
  display: flex; justify-content: space-between; align-items: center;
  padding: 10px 14px; border-bottom: 1px solid #333;
  background: #171a1f; border-radius: 8px 8px 0 0;
}
.hs-edit-panel-head b { color: #ff6b8a; font-size: 12px; }
.hs-edit-panel-head button {
  background: #ff3b6b; color: #fff; border: none;
  padding: 5px 10px; border-radius: 4px; cursor: pointer;
  font-family: var(--font-mono); font-size: 11px; font-weight: 600;
}
.hs-edit-panel-head button:hover { background: #ff5c87; }
.hs-edit-panel-head button.copied { background: #4ade9a; }
.hs-edit-panel pre {
  margin: 0; padding: 12px 14px; overflow: auto; flex: 1;
  font-family: var(--font-mono); font-size: 11px; line-height: 1.65;
  white-space: pre; color: #cfd3d8;
}
.hs-edit-panel pre .hs-group { color: #ff6b8a; display: block; margin-top: 6px; }
.hs-edit-panel pre .hs-id { color: #ffcc66; }
.hs-edit-panel pre .hs-coord { color: #7ee; }
@media (max-width: 700px) { .hs-edit-panel { width: calc(100% - 32px); right: 16px; } }
.hotspot-panel .hp-title {
  font-family: var(--font-mono); font-size: 11px; color: var(--amber);
  letter-spacing: 0.06em; margin-bottom: 8px;
}
.hotspot-panel .hp-empty { color: var(--text3); font-style: italic; }

/* ── Quiz ── */
.quiz {
  margin: 28px 0; padding: 18px 22px;
  background: var(--bg2); border: 1px solid var(--border);
  border-radius: 10px;
}
.quiz .q-label {
  font-family: var(--font-mono); font-size: 11px; color: var(--purple);
  letter-spacing: 0.1em; text-transform: uppercase; margin-bottom: 8px;
}
.quiz .q-text {
  font-size: 15px; color: var(--text); margin-bottom: 14px; line-height: 1.7;
  font-weight: 500;
}
.quiz .q-options { display: flex; flex-direction: column; gap: 8px; }
.quiz .q-opt {
  text-align: left; padding: 10px 14px;
  background: var(--bg3); border: 1px solid var(--border);
  border-radius: 6px; cursor: pointer; color: var(--text2);
  font-size: 14px; line-height: 1.6; font-family: inherit;
  transition: all 0.15s;
}
.quiz .q-opt:hover:not(.answered) { border-color: var(--text2); color: var(--text); }
.quiz .q-opt.correct {
  border-color: var(--accent); background: rgba(74,222,154,0.08); color: var(--text);
}
.quiz .q-opt.wrong {
  border-color: var(--accent3); background: rgba(255,107,107,0.08); color: var(--text);
}
.quiz .q-feedback {
  margin-top: 12px; padding: 10px 14px;
  border-radius: 6px; font-size: 13.5px; line-height: 1.7;
  display: none;
}
.quiz .q-feedback.show { display: block; }
.quiz .q-feedback.correct { background: rgba(74,222,154,0.08); color: var(--text); border-left: 3px solid var(--accent); }
.quiz .q-feedback.wrong { background: rgba(255,107,107,0.08); color: var(--text); border-left: 3px solid var(--accent3); }