/* ===== 主题变量：默认深色星空；[data-theme="light"] 覆盖为浅色 ===== */
:root {
  --bg: #0b1026; --surface: #111736; --surface2: #0f1530;
  --text: #e2e8f0; --text2: #cbd5e1; --muted: #94a3b8; --faint: #64748b; --brand: #f8fafc;
  --border: #1e293b; --border2: #334155; --control-bg: #1e293b; --hover: #1a2340;
  --link: #7dd3fc; --gold: #fbbf24; --bright: #ffffff;
  --done-bg: #14532d; --done-fg: #4ade80; --warn-bg: #78350f;
  --user-bubble: #0c4a6e; --danger: #f87171;
}
[data-theme="light"] {
  --bg: #f5f7fa; --surface: #ffffff; --surface2: #f8fafc;
  --text: #1f2937; --text2: #374151; --muted: #6b7280; --faint: #9ca3af; --brand: #111827;
  --border: #e5e7eb; --border2: #d1d5db; --control-bg: #f1f5f9; --hover: #eef2f7;
  --link: #0369a1; --gold: #b45309; --bright: #111827;
  --done-bg: #dcfce7; --done-fg: #16a34a; --warn-bg: #fef3c7;
  --user-bubble: #dbeafe; --danger: #dc2626;
}

* { box-sizing: border-box; }
body { margin: 0; font-family: "PingFang SC", "Microsoft YaHei", sans-serif; background: var(--bg); color: var(--text); }
a { color: var(--link); text-decoration: none; }
.topnav { display: flex; align-items: center; justify-content: space-between; padding: 14px 28px; background: var(--surface); border-bottom: 1px solid var(--border); }
.brand { font-size: 18px; font-weight: 700; color: var(--brand); }
.brand-wrap { display: flex; align-items: center; gap: 14px; }
.subject-switch { display: inline-flex; gap: 2px; padding: 2px; background: var(--control-bg); border: 1px solid var(--border2); border-radius: 999px; }
.subject-switch button { border: none; background: transparent; color: var(--muted); padding: 4px 14px; border-radius: 999px; cursor: pointer; font-size: 13px; }
.subject-switch button:hover { color: var(--bright); }
.subject-switch button.active { background: #0369a1; color: #fff; }
.subject-switch button.wip:not(.active) { opacity: .55; }
.topnav nav a { margin-left: 20px; color: var(--text2); }
.topnav nav a:hover { color: var(--bright); }
.footer { padding: 28px; text-align: center; color: var(--faint); border-top: 1px solid var(--border); margin-top: 40px; font-size: 13px; }
.beian { color: var(--faint); }

.entry-cards { display: flex; gap: 16px; padding: 24px 28px 8px; flex-wrap: wrap; }
.card { flex: 1; min-width: 220px; background: var(--surface); border: 1px solid var(--border); border-radius: 12px; padding: 18px 20px; color: var(--text); transition: border-color .2s; }
.card:hover { border-color: #38bdf8; }
.card h3 { margin: 0 0 8px; }
.card p { margin: 0; color: var(--muted); font-size: 14px; }
.card.disabled { opacity: .55; cursor: default; }
.card.disabled:hover { border-color: var(--border); }

.breadcrumb { padding: 8px 28px; color: var(--muted); font-size: 14px; }
.star-wrap { display: flex; height: calc(100vh - 260px); min-height: 480px; }
#chart { flex: 1; min-width: 0; }
.drawer { width: 560px; max-width: 90vw; flex-shrink: 0; overflow-y: auto; background: var(--surface2); border-left: 1px solid var(--border); padding: 20px 24px; position: relative; transition: width .2s ease; }
.drawer.wide { width: 62%; }
.drawer.hidden { display: none; }
.drawer-close { position: absolute; right: 12px; top: 10px; background: none; border: none; color: var(--muted); font-size: 22px; cursor: pointer; }
.drawer-wide { position: absolute; right: 44px; top: 10px; background: var(--control-bg); border: 1px solid var(--border2); border-radius: 6px; color: var(--text2); font-size: 13px; padding: 3px 10px; cursor: pointer; }
.drawer-wide:hover { border-color: #38bdf8; color: #fff; }
@media (max-width: 767px) {
  .drawer, .drawer.wide { width: 100vw; max-width: 100vw; }
  .drawer-wide { display: none; }
}
.drawer h2 { margin: 0 0 4px; }
.drawer h4 { margin: 16px 0 6px; color: var(--link); }
.muted { color: var(--muted); }
details.level { background: var(--surface); border-radius: 8px; padding: 8px 12px; margin: 6px 0; }
details.level summary { cursor: pointer; color: var(--gold); }
.progress-btns { display: flex; gap: 8px; margin: 12px 0; }
.pbtn, .btn { background: var(--control-bg); color: var(--text2); border: 1px solid var(--border2); border-radius: 8px; padding: 6px 14px; cursor: pointer; font-size: 13px; }
.pbtn.active { background: #0369a1; color: #fff; border-color: #38bdf8; }
.btn { display: inline-block; margin-top: 12px; background: #0369a1; color: #fff; }

.page { max-width: 860px; margin: 0 auto; padding: 24px; }
.year-filter { margin: 16px 0; display: flex; gap: 8px; flex-wrap: wrap; }
.yr { background: var(--control-bg); color: var(--text2); border: 1px solid var(--border2); border-radius: 999px; padding: 4px 14px; cursor: pointer; }
.yr.active { background: #0369a1; color: #fff; }
.timeline { list-style: none; padding: 0; }
.tl-item { display: flex; gap: 16px; margin-bottom: 18px; }
.tl-year { flex: 0 0 56px; font-weight: 700; color: var(--gold); }
.tl-card { background: var(--surface); border: 1px solid var(--border); border-radius: 10px; padding: 12px 16px; flex: 1; }
.tl-card h3 { margin: 0 0 6px; }
.tl-card p { margin: 0 0 6px; color: var(--text2); }

.demo { background: var(--surface); border: 1px solid var(--border); border-radius: 12px; padding: 20px 24px; margin-top: 20px; }
.node-tag { font-size: 12px; color: var(--faint); font-weight: 400; }
.gd-controls { display: flex; gap: 24px; flex-wrap: wrap; align-items: center; margin: 14px 0; }
.gd-controls label { display: flex; flex-direction: column; font-size: 13px; color: var(--text2); gap: 4px; }
#gd-restart { background: #0369a1; color: #fff; border: none; border-radius: 8px; padding: 8px 18px; cursor: pointer; }
.gd-canvases { display: flex; gap: 20px; flex-wrap: wrap; }
.gd-canvases canvas { background: var(--surface2); border: 1px solid var(--border); border-radius: 10px; }
.tts-btn { margin-left: 10px; background: var(--control-bg); color: var(--text2); border: 1px solid var(--border2); border-radius: 6px; padding: 2px 10px; font-size: 12px; cursor: pointer; }
.tts-btn:hover { border-color: #38bdf8; color: #fff; }
.tts-btn:disabled { opacity: 0.6; cursor: wait; }
.practice-card { background: var(--surface); border: 1px solid var(--border); border-left: 3px solid var(--gold); border-radius: 8px; padding: 10px 14px; margin: 8px 0; font-size: 14px; line-height: 1.6; }
.practice-tag { color: var(--gold); margin-right: 6px; }
.path-progress { margin: 12px 0 20px; }
.path-bar { height: 8px; background: var(--control-bg); border-radius: 999px; overflow: hidden; }
.path-bar > div { height: 100%; background: #22c55e; transition: width .3s; }
.path-list { list-style: none; padding: 0; counter-reset: step; }
.path-item { display: flex; gap: 14px; align-items: flex-start; background: var(--surface); border: 1px solid var(--border); border-radius: 10px; padding: 14px 18px; margin-bottom: 12px; cursor: pointer; }
.path-item:hover { border-color: #38bdf8; }
.path-idx { flex: 0 0 30px; height: 30px; border-radius: 50%; background: var(--control-bg); color: var(--link); display: flex; align-items: center; justify-content: center; font-weight: 700; }
.path-item.done .path-idx { background: var(--done-bg); color: var(--done-fg); }
.path-body { flex: 1; }
.path-body h3 { margin: 0 0 4px; font-size: 16px; }
.path-body p { margin: 0; color: var(--muted); font-size: 13px; }
.path-status { flex: 0 0 auto; font-size: 12px; border-radius: 999px; padding: 3px 12px; background: var(--control-bg); color: var(--muted); }
.path-status.done { background: var(--done-bg); color: var(--done-fg); }
.path-status.doing { background: var(--warn-bg); color: var(--gold); }
.ai-box { background: var(--surface2); border: 1px solid var(--border); border-radius: 10px; padding: 14px; margin: 8px 0 16px; }
.ai-input { width: 100%; background: var(--surface); border: 1px solid var(--border2); border-radius: 8px; color: var(--text); padding: 8px 12px; font-size: 14px; margin: 8px 0; }
.ai-input:focus { outline: none; border-color: #38bdf8; }
.ai-btns { margin: 6px 0; }
.ai-result { font-size: 14px; line-height: 1.7; }
.ai-result p { margin: 8px 0; }
.ai-meta, .ai-disclaimer { font-size: 12px; margin: 8px 0 0; }
.ai-error { color: var(--danger); }
.ai-bubbles { max-height: 320px; overflow-y: auto; margin-bottom: 8px; }
.ai-bubble { max-width: 88%; border-radius: 12px; padding: 8px 12px; margin: 6px 0; font-size: 14px; line-height: 1.6; }
.ai-bubble.from-ai { background: var(--surface); border: 1px solid var(--border2); margin-right: auto; }
.ai-bubble.from-user { background: var(--user-bubble); margin-left: auto; }

/* 欢迎引导 */
.welcome { position: fixed; inset: 0; background: rgba(5,8,20,.75); z-index: 100; display: flex; align-items: center; justify-content: center; padding: 16px; }
.welcome.hidden { display: none; }
.welcome-card { background: var(--surface2); border: 1px solid var(--border2); border-radius: 14px; max-width: 520px; width: 100%; max-height: 85vh; overflow-y: auto; padding: 26px 28px; position: relative; color: var(--text); }
.welcome-card h2 { margin: 0 0 10px; }
.welcome-card h4 { color: var(--link); margin: 14px 0 6px; }
.welcome-card ol { padding-left: 20px; line-height: 1.9; margin: 6px 0; }
.welcome-card b { color: var(--gold); }
.welcome-close { position: absolute; right: 12px; top: 10px; background: none; border: none; color: var(--muted); font-size: 24px; cursor: pointer; }
.welcome-go { margin-top: 10px; width: 100%; padding: 10px; font-size: 15px; }
.level-toggle { margin-left: 20px; background: var(--control-bg); color: var(--text2); border: 1px solid var(--border2); border-radius: 999px; padding: 4px 14px; font-size: 13px; cursor: pointer; }
.level-toggle:hover { border-color: #38bdf8; color: #fff; }
.level-switch { margin: 4px 0 0; font-size: 13px; }

/* 抽屉工具条：悬浮固定在右上角，滚动不丢 */
.drawer-tools { position: sticky; top: 8px; float: right; z-index: 10; display: flex; gap: 6px; margin-left: 8px; }
.drawer-tools .drawer-wide { position: static; }
.drawer-tools .drawer-close { position: static; background: var(--control-bg); border-radius: 6px; width: 30px; height: 30px; line-height: 1; }
/* 时间线 v2：按年份分组的紧凑卡片 */
.page-wide { max-width: 960px; }
.tl-year-head { margin: 26px 0 10px; color: var(--gold); font-size: 20px; border-bottom: 1px solid var(--border); padding-bottom: 6px; }
.tl-group { list-style: none; padding: 0; margin: 0; }
.tl-item { display: flex; gap: 12px; margin-bottom: 10px; }
.tl-meta { flex: 0 0 108px; display: flex; flex-direction: column; gap: 6px; align-items: flex-start; padding-top: 2px; }
.tl-date { font-weight: 700; color: var(--gold); font-size: 14px; }
.tl-branch { font-size: 11px; border: 1px solid; border-radius: 999px; padding: 1px 8px; white-space: nowrap; }
.tl-card { padding: 10px 14px; }
.tl-card h3 { font-size: 15px; margin: 0 0 4px; }
.tl-card p { font-size: 13px; margin: 0 0 4px; }
.tl-links { display: flex; gap: 14px; flex-wrap: wrap; font-size: 12px; }
.tl-src { color: var(--faint); }

/* 回到顶部 */
#to-top { display: none; position: fixed; right: 22px; bottom: 26px; z-index: 90; width: 42px; height: 42px; border-radius: 50%; border: 1px solid var(--border2); background: var(--control-bg); color: var(--text); font-size: 20px; cursor: pointer; box-shadow: 0 2px 10px rgba(0,0,0,.4); }
#to-top:hover { background: #0369a1; border-color: #38bdf8; }

/* 历史坐标 */
.tl-hist-item { font-size: 13px; margin: 4px 0; }
.tl-hist-item .yr { color: var(--gold); margin-right: 6px; }

/* 时间线锚点定位高亮 */
.tl-item:target .tl-card { outline: 2px solid var(--gold); box-shadow: 0 0 16px rgba(251,191,36,.35); }
/* 演示实验室导航卡片 */
.demo-nav { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 14px; margin: 18px 0 8px; }
.demo-card { background: var(--surface); border: 1px solid var(--border); border-radius: 10px; padding: 14px 16px; color: var(--text); transition: border-color .2s; }
.demo-card:hover { border-color: #38bdf8; }
.demo-card-disabled { opacity: .5; cursor: not-allowed; }
.demo-card h3 { margin: 0 0 6px; font-size: 15px; }
.demo-card p { margin: 0 0 8px; color: var(--muted); font-size: 13px; }
.demo-mount { margin-top: 10px; }

/* 位置路径链接 */
.path-link { color: var(--link); text-decoration: none; }
.path-link:hover { text-decoration: underline; }
.path-current { color: var(--muted); }

/* 导航搜索 */
.search-box { position: relative; }
#nav-search { background: var(--surface); border: 1px solid var(--border2); border-radius: 8px; color: var(--text); padding: 5px 10px; font-size: 13px; width: 150px; outline: none; }
#nav-search:focus { border-color: #38bdf8; width: 190px; }
.search-results { position: absolute; top: 34px; right: 0; width: 280px; background: var(--surface2); border: 1px solid var(--border2); border-radius: 10px; box-shadow: 0 8px 24px rgba(0,0,0,.5); z-index: 200; overflow: hidden; }
.search-results.hidden { display: none; }
.sr-item { display: flex; align-items: center; gap: 8px; padding: 9px 12px; color: var(--text); text-decoration: none; font-size: 13px; border-bottom: 1px solid var(--hover); }
.sr-item:hover { background: var(--hover); }
.sr-item b { flex: 1; font-weight: 500; }
.sr-type { font-size: 11px; padding: 1px 6px; border-radius: 4px; background: var(--control-bg); color: var(--muted); flex-shrink: 0; }
.sr-concept { color: var(--link); }
.sr-category { color: var(--gold); }
.sr-branch { font-size: 11px; color: var(--faint); flex-shrink: 0; }
.sr-empty { padding: 12px; color: var(--faint); font-size: 13px; text-align: center; }
@media (max-width: 767px) { #nav-search { width: 90px; } #nav-search:focus { width: 120px; } }

/* 实验室分组 */
.lab-group { margin: 26px 0 10px; color: var(--link); font-size: 17px; border-left: 3px solid #38bdf8; padding-left: 10px; }

/* 星图页返回来源按钮 */
.back-from { position: fixed; left: 18px; bottom: 22px; z-index: 95; text-decoration: none; }