/* ==========================================================================
   视频号洞察 · 共享样式
   四层结构：L1 总目录 / L2 视频目录 / L3 内容框架 / L4 单集详情
   主题：浅色（Light）
   ========================================================================== */

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

:root {
  --bg: #f4f6fa;
  --card: #ffffff;
  --ink: #1f2430;
  --ink-2: #4a5163;
  --ink-3: #8b93a5;
  --line: #e4e8f0;
  --brand: #1d3557;
  --brand-2: #2a5b8f;
  --brand-soft: #eef3fb;
  --accent: #c1121f;
  --gold: #c99a2e;
  --radius: 14px;
  --shadow: 0 2px 14px rgba(20, 40, 80, 0.06);
  --shadow-hover: 0 8px 28px rgba(20, 40, 80, 0.12);
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei",
    "Hiragino Sans GB", "Helvetica Neue", Arial, sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--brand-2); text-decoration: none; }
a:hover { text-decoration: underline; }

.wrap { max-width: 1080px; margin: 0 auto; padding: 24px 20px 60px; }

/* ---------- Breadcrumb ---------- */
.crumb {
  font-size: 13px; color: var(--ink-3); margin-bottom: 18px;
  display: flex; align-items: center; gap: 6px; flex-wrap: wrap;
}
.crumb a { color: var(--ink-2); }
.crumb .sep { color: var(--ink-3); opacity: .6; }

/* ---------- Hero ---------- */
.hero {
  background: linear-gradient(135deg, #16213e 0%, #1d3557 55%, #2a5b8f 100%);
  color: #fff; border-radius: var(--radius); padding: 44px 40px;
  margin-bottom: 26px; position: relative; overflow: hidden;
}
.hero::after {
  content: ""; position: absolute; top: -40%; right: -8%;
  width: 380px; height: 380px; border-radius: 50%;
  background: radial-gradient(circle, rgba(255, 214, 102, .10) 0%, transparent 70%);
}
.hero .kicker {
  font-size: 12px; letter-spacing: 3px; text-transform: uppercase;
  color: #ffd666; opacity: .9; margin-bottom: 10px;
}
.hero h1 { font-size: 30px; font-weight: 700; letter-spacing: .5px; margin-bottom: 10px; }
.hero .lead { font-size: 15px; opacity: .85; max-width: 720px; }
.hero .chips { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 20px; }
.hero .chip {
  font-size: 12.5px; background: rgba(255,255,255,.12); border: 1px solid rgba(255,255,255,.2);
  padding: 5px 13px; border-radius: 20px;
}
.hero .chip b { color: #ffd666; }

/* ---------- Section heading ---------- */
.sec-title {
  font-size: 20px; font-weight: 700; color: var(--ink);
  border-left: 4px solid var(--brand); padding-left: 12px; margin: 30px 0 4px;
}
.sec-desc { font-size: 13.5px; color: var(--ink-3); padding-left: 16px; margin-bottom: 20px; }

/* ---------- L1: channel grid ---------- */
.chan-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); gap: 18px; }
.chan-card {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 22px; box-shadow: var(--shadow); transition: transform .18s, box-shadow .18s;
  display: flex; flex-direction: column;
}
.chan-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-hover); }
.chan-card .tag-row { display: flex; gap: 8px; margin-bottom: 12px; flex-wrap: wrap; }
.chan-card .no {
  font-size: 12px; font-weight: 700; color: #fff; background: var(--brand);
  border-radius: 6px; padding: 2px 9px;
}
.chan-card .cat {
  font-size: 12px; color: var(--brand-2); background: var(--brand-soft);
  border-radius: 6px; padding: 2px 9px;
}
.chan-card h3 { font-size: 19px; margin-bottom: 6px; color: var(--ink); }
.chan-card .who { font-size: 13px; color: var(--ink-3); margin-bottom: 10px; }
.chan-card .desc { font-size: 13.5px; color: var(--ink-2); flex: 1; margin-bottom: 16px; }
.chan-card .stats { display: flex; gap: 18px; font-size: 12px; color: var(--ink-3); margin-bottom: 16px; }
.chan-card .stats b { color: var(--brand); font-size: 16px; display: block; }
.chan-card .go {
  display: inline-block; text-align: center; background: var(--brand); color: #fff;
  border-radius: 9px; padding: 10px 16px; font-size: 14px; font-weight: 600; transition: background .15s;
}
.chan-card .go:hover { background: var(--brand-2); text-decoration: none; }

/* ---------- L2: episode list ---------- */
.ep-toolbar { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 20px; }
.ep-toolbar .fbtn {
  font-size: 13px; padding: 6px 14px; border-radius: 18px; border: 1px solid var(--line);
  background: #fff; color: var(--ink-2); cursor: pointer; transition: all .15s;
}
.ep-toolbar .fbtn.active, .ep-toolbar .fbtn:hover { background: var(--brand); color: #fff; border-color: var(--brand); }

.ep-list { display: flex; flex-direction: column; gap: 14px; }
.ep-card {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 18px 20px; box-shadow: var(--shadow); display: flex; gap: 18px;
  transition: box-shadow .18s, border-color .18s;
}
.ep-card:hover { box-shadow: var(--shadow-hover); border-color: #cdd6e8; }
.ep-card .idx {
  flex-shrink: 0; width: 46px; height: 46px; border-radius: 11px;
  background: linear-gradient(135deg, #1d3557, #2a5b8f); color: #fff;
  display: flex; align-items: center; justify-content: center; font-weight: 700; font-size: 16px;
}
.ep-card .idx.hot { background: linear-gradient(135deg, #b8860b, #e0a800); }
.ep-card .body { flex: 1; min-width: 0; }
.ep-card h4 { font-size: 16.5px; color: var(--ink); margin-bottom: 6px; line-height: 1.5; }
.ep-card .meta { display: flex; gap: 16px; flex-wrap: wrap; font-size: 12px; color: var(--ink-3); margin-bottom: 8px; }
.ep-card .desc { font-size: 13.8px; color: var(--ink-2); }
.ep-card .tags { display: flex; gap: 6px; flex-wrap: wrap; margin-top: 10px; }
.ep-card .tags span {
  font-size: 11.5px; background: #f1f4fa; color: var(--ink-2); padding: 2px 10px; border-radius: 11px;
}
.ep-card .links { display: flex; gap: 10px; margin-top: 12px; flex-wrap: wrap; }
.ep-card .links a {
  font-size: 12.5px; padding: 5px 12px; border-radius: 8px; border: 1px solid var(--line);
  background: #fff; color: var(--brand-2); font-weight: 600;
}
.ep-card .links a:hover { background: var(--brand-soft); text-decoration: none; }
.ep-card .links a.primary { background: var(--brand); color: #fff; border-color: var(--brand); }
.ep-card .links a.primary:hover { background: var(--brand-2); }

/* ---------- L3: framework ---------- */
.fw-tree { margin-top: 10px; }
.fw-root {
  background: linear-gradient(135deg, #16213e, #1d3557); color: #fff;
  border-radius: 11px; padding: 16px 24px; text-align: center; font-weight: 700; font-size: 16px;
  margin-bottom: 20px; letter-spacing: .5px;
}
.fw-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(330px, 1fr)); gap: 18px; }
.fw-branch { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow); }
.fw-branch .head {
  color: #fff; padding: 14px 18px; font-weight: 700; font-size: 15.5px;
  display: flex; align-items: center; gap: 9px;
}
.fw-branch .head .dot { width: 9px; height: 9px; border-radius: 50%; background: rgba(255,255,255,.7); }
.fw-branch .inner { padding: 16px 18px; }
.fw-sub { padding-left: 13px; border-left: 2px solid var(--line); margin-bottom: 15px; }
.fw-sub:last-child { margin-bottom: 0; }
.fw-sub .st { font-size: 13.5px; font-weight: 700; color: var(--ink); margin-bottom: 4px; }
.fw-sub .sd { font-size: 12.5px; color: var(--ink-3); margin-bottom: 8px; line-height: 1.6; }
.fw-sub .items { display: flex; flex-direction: column; gap: 7px; }
.fw-sub .item {
  font-size: 13px; background: #f7f9fc; border: 1px solid var(--line); border-radius: 8px;
  padding: 8px 11px; display: flex; gap: 9px; align-items: flex-start; transition: background .15s;
}
.fw-sub .item:hover { background: var(--brand-soft); }
.fw-sub .item .n {
  flex-shrink: 0; font-size: 11px; font-weight: 700; color: #fff; background: var(--brand-2);
  border-radius: 5px; padding: 1px 6px; margin-top: 2px;
}
.fw-sub .item a { color: var(--ink); font-weight: 600; }
.fw-sub .item a:hover { color: var(--brand-2); }
.fw-sub .item .go4 { margin-left: auto; font-size: 11.5px; color: var(--brand-2); white-space: nowrap; }

/* branch colors */
.c1 { background: linear-gradient(135deg, #1565c0, #1e88e5); }
.c2 { background: linear-gradient(135deg, #00695c, #00897b); }
.c3 { background: linear-gradient(135deg, #b45309, #d97706); }
.c4 { background: linear-gradient(135deg, #6a1b9a, #8e24aa); }
.c5 { background: linear-gradient(135deg, #b71c1c, #e53935); }
.c6 { background: linear-gradient(135deg, #283593, #3f51b5); }
.c7 { background: linear-gradient(135deg, #33691e, #558b2f); }
.c8 { background: linear-gradient(135deg, #37474f, #546e7a); }

/* ---------- L4: episode detail ---------- */
.ep-detail { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); padding: 34px 38px; }
.ep-detail h1 { font-size: 24px; line-height: 1.5; margin-bottom: 10px; color: var(--ink); }
.ep-detail .dmeta { display: flex; gap: 18px; flex-wrap: wrap; font-size: 13px; color: var(--ink-3); margin-bottom: 18px; }
.ep-detail .videobox {
  background: var(--brand-soft); border: 1px dashed #b9c9e4; border-radius: 11px;
  padding: 16px 18px; margin-bottom: 24px; font-size: 14px;
}
.ep-detail .videobox .lbl { font-size: 12px; color: var(--ink-3); margin-bottom: 4px; }
.ep-detail .videobox a { font-weight: 700; word-break: break-all; }
.ep-detail h2 {
  font-size: 16px; margin: 26px 0 10px; padding-left: 11px; border-left: 3px solid var(--brand);
  color: var(--ink);
}
.ep-detail .txt { font-size: 15px; color: var(--ink-2); line-height: 1.95; }
.ep-detail .txt p { margin-bottom: 14px; }
.ep-detail .txt .hl { background: linear-gradient(transparent 62%, #ffe9a8 62%); font-weight: 600; color: var(--ink); }
.ep-detail blockquote {
  background: #f7f9fc; border-left: 3px solid var(--gold); padding: 14px 18px;
  border-radius: 0 9px 9px 0; margin: 16px 0; font-size: 14.5px; color: var(--ink-2);
}
.ep-detail .note {
  margin-top: 26px; font-size: 12.5px; color: var(--ink-3); background: #fafbfd;
  border: 1px solid var(--line); border-radius: 9px; padding: 12px 16px;
}
.epnav { display: flex; justify-content: space-between; gap: 12px; margin-top: 24px; }
.epnav a {
  font-size: 13.5px; padding: 9px 16px; border-radius: 9px; border: 1px solid var(--line);
  background: #fff; color: var(--brand-2); font-weight: 600; max-width: 46%;
  overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
}
.epnav a:hover { background: var(--brand-soft); text-decoration: none; }

/* ---------- misc ---------- */
.notice {
  background: #fff8e6; border: 1px solid #f0dca0; border-radius: 11px; padding: 14px 18px;
  font-size: 13.5px; color: #7a5c12; margin: 20px 0;
}
.notice b { color: #5c4408; }
.pill-row { display: flex; gap: 10px; flex-wrap: wrap; margin: 18px 0; }
.pill-row .pill {
  background: #fff; border: 1px solid var(--line); border-radius: 22px; padding: 6px 15px;
  font-size: 13px; color: var(--ink-2);
}
.pill-row .pill b { color: var(--brand); }

.footer { text-align: center; font-size: 12.5px; color: var(--ink-3); margin-top: 40px; padding-top: 20px; border-top: 1px solid var(--line); }

@media (max-width: 720px) {
  .hero { padding: 30px 22px; }
  .hero h1 { font-size: 23px; }
  .ep-card { flex-direction: column; gap: 12px; }
  .ep-detail { padding: 22px 18px; }
  .fw-grid, .chan-grid { grid-template-columns: 1fr; }
  .epnav a { max-width: 100%; }
}