/* 格物物理 · 可视化课件 —— 内测样品样式 */
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
:root {
  --ink: #0f172a;
  --sub: #5b6b7f;
  --line: #dfe5ec;
  --paper: #f7f9fb;
  --teal: #0f766e;
  --teal-2: #0d9488;
  --amber: #d97706;
  --violet: #7c3aed;
}
body {
  font-family: 'Microsoft YaHei', 'PingFang SC', 'Noto Sans SC', system-ui, sans-serif;
  background: #eef1f4;
  color: var(--ink);
  -webkit-font-smoothing: antialiased;
}
.serif { font-family: 'Noto Serif SC', 'Source Han Serif SC', 'STSong', 'SimSun', serif; }

/* ---------- 顶栏 ---------- */
.topbar {
  position: sticky; top: 0; z-index: 40;
  background: var(--ink); color: #e6edf5;
  display: flex; align-items: center; gap: 16px;
  padding: 0 22px; height: 58px;
}
.brand { display: flex; align-items: center; gap: 10px; color: #f8fafc; text-decoration: none; }
.brand .mark {
  width: 27px; height: 27px; border-radius: 8px;
  background: linear-gradient(135deg, #14b8a6, #0f766e);
  display: grid; place-items: center; font-size: 14px; font-weight: 700; color: #fff;
}
.brand .name { font-family: 'Noto Serif SC', 'Source Han Serif SC', 'STSong', serif; font-size: 19px; letter-spacing: 1.5px; }
.chips { display: flex; gap: 7px; flex-wrap: wrap; margin-left: 10px; }
.chip {
  padding: 4px 11px; border-radius: 999px; font-size: 12.5px; color: #9fb0c3;
  border: 1px solid rgba(255,255,255,.14); background: rgba(255,255,255,.03);
}
.chip.active { color: #fff; background: rgba(13,148,136,.22); border-color: rgba(20,184,166,.55); }
.chip.soon { opacity: .5; }
.topbar .right { margin-left: auto; display: flex; align-items: center; gap: 10px; }
.badge-beta {
  font-size: 12px; padding: 3px 10px; border-radius: 999px;
  background: #f59e0b; color: #3b2200; font-weight: 700; letter-spacing: .3px;
}
.topbar .hint { font-size: 12px; color: #8496aa; }

/* ---------- 首页 ---------- */
.hero { max-width: 1260px; margin: 0 auto; padding: 40px 24px 6px; }
.hero h1 {
  font-family: 'Noto Serif SC', 'Source Han Serif SC', 'STSong', serif;
  font-size: 38px; margin: 0 0 12px; letter-spacing: 1px;
}
.hero .lead { color: var(--sub); font-size: 15.5px; line-height: 1.8; max-width: 780px; margin: 0; }
.hero .lead b { color: var(--teal); }
.feature-row { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 20px; }
.feat {
  display: flex; align-items: center; gap: 8px; font-size: 13px; color: #0f766e;
  background: #e7f5f2; border: 1px solid #c7e7e1; padding: 7px 13px; border-radius: 999px;
}
.feat .ic { font-weight: 700; }
.stats { display: flex; gap: 26px; margin-top: 26px; flex-wrap: wrap; }
.stat { border-left: 3px solid var(--teal-2); padding-left: 12px; }
.stat b { display: block; font-size: 22px; font-family: 'Noto Serif SC', serif; }
.stat span { font-size: 12.5px; color: var(--sub); }

/* ---------- 目录 ---------- */
.section { max-width: 1260px; margin: 0 auto; padding: 0 24px; }
.chapter-head { display: flex; align-items: baseline; gap: 10px; margin: 34px 0 14px; flex-wrap: wrap; }
.chapter-head h2 {
  font-family: 'Noto Serif SC', 'Source Han Serif SC', 'STSong', serif;
  font-size: 22px; margin: 0; letter-spacing: .5px;
}
.chapter-head .tag {
  font-size: 12px; color: var(--sub); background: #fff;
  border: 1px solid var(--line); padding: 2px 9px; border-radius: 6px;
}
.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(228px, 1fr)); gap: 14px; }
.card {
  background: #fff; border: 1px solid var(--line); border-radius: 16px; overflow: hidden;
  cursor: pointer; transition: transform .18s, box-shadow .18s, border-color .18s;
  display: flex; flex-direction: column; text-align: left;
}
.card:hover { transform: translateY(-3px); box-shadow: 0 16px 34px -20px rgba(15,23,42,.5); border-color: #c9d6e3; }
.card .thumb { height: 116px; display: grid; place-items: center; position: relative; overflow: hidden; }
.card .thumb::after {
  content: ''; position: absolute; inset: 0;
  background-image: linear-gradient(rgba(15,23,42,.045) 1px, transparent 1px), linear-gradient(90deg, rgba(15,23,42,.045) 1px, transparent 1px);
  background-size: 22px 22px;
}
.card .thumb .icon-svg { width: 62px; height: 62px; position: relative; z-index: 1; }
.card .body { padding: 13px 15px 15px; display: flex; flex-direction: column; gap: 7px; flex: 1; }
.card h3 { margin: 0; font-size: 15.5px; line-height: 1.45; }
.card .meta { font-size: 12px; color: var(--sub); display: flex; gap: 6px; flex-wrap: wrap; }
.card .tag {
  font-size: 11.5px; color: #0f766e; background: #eefaf7;
  border: 1px solid #d3ece6; padding: 1px 7px; border-radius: 5px;
}
.card .open-hint { margin-top: auto; font-size: 12px; color: #9aa8b8; padding-top: 6px; }
.card.soon { cursor: default; opacity: .62; background: #f4f7f9; }
.card.soon:hover { transform: none; box-shadow: none; border-color: var(--line); }

/* ---------- 页脚 ---------- */
.footer {
  max-width: 1260px; margin: 46px auto 0; padding: 22px 24px 44px;
  color: #7b8a9b; font-size: 12.5px; line-height: 1.95;
  border-top: 1px solid var(--line);
}
.footer b { color: #4b5c6e; }

/* ---------- 阅读器 ---------- */
#viewer { position: fixed; inset: 0; background: #f4f7fa; z-index: 60; display: flex; flex-direction: column; }
#viewer[hidden] { display: none; }
.v-head { height: 56px; background: var(--ink); color: #e6edf5; display: flex; align-items: center; gap: 14px; padding: 0 18px; flex: none; }
.v-head .title { font-size: 15px; font-weight: 700; }
.v-head .sub { font-size: 12px; color: #9fb0c3; }
.v-head .spacer { flex: 1; }
.v-head .close {
  border: 1px solid rgba(255,255,255,.2); background: rgba(255,255,255,.06); color: #e6edf5;
  border-radius: 9px; padding: 6px 12px; font-size: 12.5px; cursor: pointer;
}
.v-head .close:hover { background: rgba(255,255,255,.14); }
.v-body { flex: 1; display: grid; grid-template-columns: 216px minmax(0, 1fr) 342px; min-height: 0; }
.v-nav { background: #fff; border-right: 1px solid var(--line); overflow: auto; padding: 10px 10px 24px; }
.v-nav .nav-chapter { font-size: 11.5px; color: #8b9aab; padding: 12px 8px 5px; letter-spacing: .6px; }
.v-nav button {
  display: block; width: 100%; text-align: left; border: 0; background: none;
  padding: 8px 9px; border-radius: 9px; font-size: 13px; color: #334155; cursor: pointer; line-height: 1.4;
}
.v-nav button:hover { background: #f1f5f9; }
.v-nav button.on { background: #e7f5f2; color: #0f766e; font-weight: 700; }
.v-nav button .no { color: #94a3b8; font-size: 11px; margin-right: 6px; }
.v-nav button.on .no { color: #0d9488; }

.stage-col { display: flex; flex-direction: column; min-width: 0; padding: 14px 16px 10px; }
.stage {
  flex: 1; min-height: 0; background: #fff; border: 1px solid var(--line); border-radius: 14px;
  position: relative; display: grid; place-items: center; overflow: hidden; padding: 4px;
}
.stage svg { width: 100%; height: 100%; display: block; }
.stage-tip {
  position: absolute; right: 14px; bottom: 12px; font-size: 12px; color: #8b9aab;
  background: rgba(255,255,255,.86); border: 1px solid var(--line); border-radius: 8px; padding: 3px 9px;
  pointer-events: none;
}
.controls { display: flex; align-items: center; gap: 9px; flex-wrap: wrap; padding: 10px 2px 2px; }
.param {
  display: flex; align-items: center; gap: 8px; background: #fff; border: 1px solid var(--line);
  padding: 6px 10px; border-radius: 10px; font-size: 12.5px; color: #475569;
}
.param input[type=range] { width: 118px; accent-color: #0f766e; }
.param b { color: #0f766e; font-variant-numeric: tabular-nums; min-width: 26px; text-align: right; }
.btn {
  border: 1px solid var(--line); background: #fff; border-radius: 10px;
  padding: 7px 12px; font-size: 12.5px; color: #334155; cursor: pointer; white-space: nowrap;
}
.btn:hover { border-color: #b9c8d8; background: #fbfdff; }
.btn.primary { background: var(--teal); border-color: var(--teal); color: #fff; }
.btn.primary:hover { background: #0c6a62; }
.btn.icon { padding: 7px 10px; }
.steps { display: flex; align-items: center; gap: 9px; margin-left: auto; }
.dots { display: flex; gap: 5px; }
.dot { width: 7px; height: 7px; border-radius: 50%; background: #cbd5e1; transition: background .15s; }
.dot.on { background: var(--teal); }

.teach { background: #fff; border-left: 1px solid var(--line); overflow: auto; padding: 14px 16px 30px; }
.tabs { display: flex; gap: 6px; flex-wrap: wrap; margin-bottom: 13px; }
.tabs button {
  border: 1px solid var(--line); background: #f8fafc; border-radius: 999px;
  padding: 5px 11px; font-size: 12px; color: #5b6b7f; cursor: pointer;
}
.tabs button.on { background: var(--teal); border-color: var(--teal); color: #fff; }
.panel h4 { font-size: 13px; color: var(--teal); margin: 0 0 9px; letter-spacing: .5px; }
.panel ul { margin: 0; padding-left: 18px; font-size: 13.5px; line-height: 1.85; color: #334155; }
.panel ul li { margin-bottom: 5px; }
.panel .step-item { border: 1px solid var(--line); border-radius: 10px; padding: 9px 11px; margin-bottom: 8px; font-size: 13px; color: #475569; line-height: 1.6; }
.panel .step-item.on { border-color: var(--teal-2); background: #effcf9; }
.panel .step-item b { display: block; color: var(--ink); margin-bottom: 3px; font-size: 13px; }
.panel .q { font-size: 13.5px; line-height: 1.8; color: #334155; padding-left: 20px; position: relative; margin-bottom: 8px; }
.panel .q::before { content: '问'; position: absolute; left: 0; top: 1px; font-size: 11px; color: #b45309; background: #fef3c7; border-radius: 4px; padding: 0 4px; }
.panel .warn { font-size: 13px; line-height: 1.8; color: #9a3412; background: #fff7ed; border: 1px solid #fed7aa; border-radius: 9px; padding: 9px 11px; margin-bottom: 8px; }
.meta-card { background: #f8fafc; border: 1px solid var(--line); border-radius: 10px; padding: 10px 12px; font-size: 12.5px; color: #475569; line-height: 1.8; margin-bottom: 12px; }
.meta-card b { color: var(--ink); }

@media (max-width: 1080px) {
  .v-body { grid-template-columns: 1fr; }
  .v-nav { display: none; }
  .teach { max-height: 250px; border-left: 0; border-top: 1px solid var(--line); }
  .hero h1 { font-size: 30px; }
}
@media (max-width: 640px) {
  .grid { grid-template-columns: repeat(auto-fill, minmax(160px, 1fr)); }
  .hero { padding-top: 26px; }
  .stats { gap: 14px; }
}