/* ============================================================
   全局样式
   ============================================================ */

:root {
  --bg: #fbfaf7;
  --surface: #ffffff;
  --ink: #1c1a17;
  --ink-2: #55504a;
  --ink-3: #8b8379;
  --line: #e6e1d8;
  --line-strong: #d4ccc0;
  --accent: #2f5d50;
  --accent-soft: #eef3f1;
  --accent-ink: #1f4038;
  --warn: #a8611f;
  --danger: #a33a33;
  --radius: 14px;
  --radius-sm: 9px;
  --shadow: 0 1px 2px rgba(28, 26, 23, .04), 0 8px 24px -12px rgba(28, 26, 23, .12);
  --font: "Söhne", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, sans-serif;
  --mono: "JetBrains Mono", "SFMono-Regular", Consolas, monospace;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font);
  font-size: 15.5px;
  line-height: 1.72;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }

img { max-width: 100%; display: block; }

/* ---------------- 布局 ---------------- */

.wrap { max-width: 1080px; margin: 0 auto; padding: 0 24px; }
.wrap-narrow { max-width: 720px; margin: 0 auto; padding: 0 24px; }

/* ---------------- 顶栏 ---------------- */

header.site {
  position: sticky; top: 0; z-index: 50;
  background: rgba(251, 250, 247, .88);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--line);
}
header.site .inner {
  display: flex; align-items: center; gap: 20px;
  height: 62px;
}
.brand {
  font-weight: 620; font-size: 16px; letter-spacing: -.01em;
  color: var(--ink); display: flex; align-items: center; gap: 9px;
}
.brand:hover { text-decoration: none; }
.brand .dot {
  width: 7px; height: 7px; border-radius: 50%; background: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}
header.site nav { margin-left: auto; display: flex; align-items: center; gap: 6px; flex-wrap: wrap; }
header.site nav a {
  color: var(--ink-2); font-size: 14.5px; padding: 7px 11px; border-radius: 8px;
}
header.site nav a:hover { background: var(--surface); color: var(--ink); text-decoration: none; }
header.site nav a.active { color: var(--ink); font-weight: 550; }
.who { font-size: 13.5px; color: var(--ink-3); padding-right: 4px; }

/* ---------------- 按钮 ---------------- */

.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 7px;
  padding: 10px 18px; border-radius: var(--radius-sm);
  font-family: inherit; font-size: 14.5px; font-weight: 550; line-height: 1.2;
  border: 1px solid transparent; cursor: pointer;
  transition: background .15s, border-color .15s, transform .06s, color .15s;
  text-decoration: none;
}
.btn:hover { text-decoration: none; }
.btn:active { transform: translateY(1px); }
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: var(--accent-ink); }
.btn-ghost { background: transparent; color: var(--ink-2); border-color: var(--line-strong); }
.btn-ghost:hover { background: var(--surface); color: var(--ink); }
.btn-quiet { background: transparent; color: var(--ink-3); border: none; padding: 7px 9px; }
.btn-quiet:hover { color: var(--ink); background: var(--surface); }
.btn-block { width: 100%; }
.btn-lg { padding: 13px 24px; font-size: 15.5px; }
.btn-sm { padding: 6px 12px; font-size: 13.5px; }
.btn[disabled] { opacity: .5; pointer-events: none; }

/* ---------------- 卡片 ---------------- */

.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 22px 24px;
}
.card-tight { padding: 16px 18px; }

/* ---------------- 首页 hero ---------------- */

.hero { padding: 68px 0 40px; }
.hero h1 {
  font-size: clamp(30px, 4.4vw, 44px);
  line-height: 1.22; letter-spacing: -.025em; font-weight: 620;
  margin: 0 0 18px; max-width: 20em;
}
.hero p.lede { font-size: 17px; color: var(--ink-2); margin: 0 0 26px; max-width: 34em; }

/* ---------------- 课程网格 ---------------- */

.section-head {
  display: flex; align-items: baseline; gap: 14px;
  margin: 52px 0 20px;
}
.section-head h2 { font-size: 19px; font-weight: 600; letter-spacing: -.01em; margin: 0; }
.section-head .count { font-size: 13.5px; color: var(--ink-3); }
.section-head .spacer { flex: 1; }

.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 20px; }

.course-card {
  background: var(--surface); border: 1px solid var(--line);
  border-radius: var(--radius); overflow: hidden;
  display: flex; flex-direction: column;
  transition: border-color .18s, transform .18s, box-shadow .18s;
}
.course-card:hover {
  border-color: var(--line-strong);
  box-shadow: var(--shadow);
  transform: translateY(-2px);
}
.course-card .cover {
  aspect-ratio: 16 / 9;
  background: linear-gradient(135deg, #eef1ee 0%, #e3e8e5 55%, #dbe3df 100%);
  display: flex; align-items: center; justify-content: center;
  color: var(--ink-3); font-size: 13px; letter-spacing: .04em;
  border-bottom: 1px solid var(--line);
  position: relative;
}
.course-card .cover img { width: 100%; height: 100%; object-fit: cover; }
.course-card .body { padding: 18px 20px 20px; display: flex; flex-direction: column; gap: 8px; flex: 1; }
.course-card h3 { font-size: 16.5px; font-weight: 590; margin: 0; letter-spacing: -.01em; line-height: 1.42; }
.course-card h3 a { color: var(--ink); }
.course-card h3 a:hover { text-decoration: none; color: var(--accent); }
.course-card .sub { font-size: 14px; color: var(--ink-2); margin: 0; line-height: 1.62; }
.course-card .meta {
  margin-top: auto; padding-top: 12px;
  display: flex; align-items: center; gap: 12px;
  font-size: 13.5px; color: var(--ink-3);
}
.price { font-size: 16px; font-weight: 600; color: var(--ink); font-variant-numeric: tabular-nums; }
.price.is-free { color: var(--accent); }
.badge {
  display: inline-flex; align-items: center; gap: 5px;
  font-size: 12.5px; font-weight: 550; padding: 2px 8px; border-radius: 6px;
  background: var(--accent-soft); color: var(--accent-ink);
}
.badge-warn { background: #fbf2e6; color: var(--warn); }
.badge-muted { background: #f2efea; color: var(--ink-2); }
.badge-danger { background: #fbeceb; color: var(--danger); }

/* ---------------- 表单 ---------------- */

.field { margin-bottom: 16px; }
.field label {
  display: block; font-size: 13.5px; font-weight: 550; color: var(--ink-2);
  margin-bottom: 6px;
}
.field .hint { font-size: 12.5px; color: var(--ink-3); margin-top: 5px; line-height: 1.55; }
input[type=text], input[type=email], input[type=password], input[type=number],
input[type=url], select, textarea {
  width: 100%; padding: 10px 13px;
  font-family: inherit; font-size: 14.5px; color: var(--ink);
  background: var(--surface);
  border: 1px solid var(--line-strong); border-radius: var(--radius-sm);
  outline: none; transition: border-color .15s, box-shadow .15s;
}
input:focus, select:focus, textarea:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}
textarea { resize: vertical; min-height: 90px; line-height: 1.65; }
.row { display: flex; gap: 14px; }
.row > * { flex: 1; min-width: 0; }
.checkbox { display: flex; align-items: center; gap: 8px; font-size: 14px; color: var(--ink-2); }
.checkbox input { width: auto; }

/* ---------------- 提示条 ---------------- */

.flash {
  padding: 12px 15px; border-radius: var(--radius-sm);
  font-size: 14px; margin-bottom: 18px; line-height: 1.6;
  border: 1px solid;
}
.flash-ok { background: var(--accent-soft); border-color: #cfe0da; color: var(--accent-ink); }
.flash-err { background: #fbeceb; border-color: #eed3d1; color: var(--danger); }
.flash-info { background: #f4f2ee; border-color: var(--line); color: var(--ink-2); }

/* ---------------- 表格 ---------------- */

table.tbl { width: 100%; border-collapse: collapse; font-size: 14px; }
table.tbl th {
  text-align: left; font-weight: 550; font-size: 12.5px; color: var(--ink-3);
  text-transform: uppercase; letter-spacing: .04em;
  padding: 0 12px 9px; border-bottom: 1px solid var(--line-strong);
  white-space: nowrap;
}
table.tbl td {
  padding: 13px 12px; border-bottom: 1px solid var(--line); vertical-align: middle;
}
table.tbl tr:last-child td { border-bottom: none; }
table.tbl tr:hover td { background: #fcfbf9; }
.num { font-variant-numeric: tabular-nums; font-family: var(--mono); font-size: 13px; }

/* ---------------- 课程详情 ---------------- */

.detail-head {
  padding: 44px 0 32px;
  border-bottom: 1px solid var(--line);
}
.detail-head h1 {
  font-size: clamp(26px, 3.4vw, 36px); line-height: 1.28;
  letter-spacing: -.022em; font-weight: 620; margin: 0 0 12px;
}
.detail-head .sub { font-size: 17px; color: var(--ink-2); margin: 0 0 18px; max-width: 40em; }
.detail-body { display: grid; grid-template-columns: 1fr 330px; gap: 48px; padding: 36px 0 72px; align-items: start; }
@media (max-width: 880px) {
  .detail-body { grid-template-columns: 1fr; gap: 28px; }
}
.prose { font-size: 15.5px; color: var(--ink-2); white-space: pre-wrap; line-height: 1.8; }

.buybox { position: sticky; top: 86px; }
.buybox .price-lg { font-size: 32px; font-weight: 620; letter-spacing: -.02em; font-variant-numeric: tabular-nums; }

/* 课时列表 */
.lesson-list { list-style: none; margin: 0; padding: 0; }
.lesson-list li {
  display: flex; align-items: center; gap: 14px;
  padding: 14px 2px; border-bottom: 1px solid var(--line);
}
.lesson-list li:last-child { border-bottom: none; }
.lesson-idx {
  width: 26px; height: 26px; flex: 0 0 26px;
  display: flex; align-items: center; justify-content: center;
  border-radius: 50%; background: #f2efea; color: var(--ink-3);
  font-size: 12.5px; font-variant-numeric: tabular-nums;
}
.lesson-list li.is-playable .lesson-idx { background: var(--accent-soft); color: var(--accent-ink); }
.lesson-title { flex: 1; font-size: 14.5px; color: var(--ink); }
.lesson-list li.is-locked .lesson-title { color: var(--ink-3); }
.lesson-dur { font-size: 13px; color: var(--ink-3); font-variant-numeric: tabular-nums; }

/* ---------------- 播放页 ---------------- */

.player-shell {
  background: #14120f; border-radius: var(--radius); overflow: hidden;
  aspect-ratio: 16 / 9; position: relative;
  display: flex; align-items: center; justify-content: center;
}
.player-shell video { width: 100%; height: 100%; display: block; background: #000; }
.player-empty {
  color: #8a857e; font-size: 14px; text-align: center; padding: 32px; line-height: 1.8;
}

/* ---------------- 空状态 ---------------- */

.empty {
  text-align: center; padding: 64px 24px;
  color: var(--ink-3); font-size: 14.5px;
}
.empty strong { display: block; color: var(--ink-2); font-size: 16px; font-weight: 550; margin-bottom: 8px; }

/* ---------------- 页脚 ---------------- */

footer.site {
  border-top: 1px solid var(--line);
  margin-top: 72px; padding: 32px 0 44px;
  font-size: 13.5px; color: var(--ink-3);
}
footer.site .inner { display: flex; gap: 18px; flex-wrap: wrap; align-items: center; }
footer.site .spacer { flex: 1; }

/* ---------------- 工具类 ---------------- */

.muted { color: var(--ink-3); }
.small { font-size: 13.5px; }
.mt-0 { margin-top: 0; }
.mt-1 { margin-top: 8px; }
.mt-2 { margin-top: 16px; }
.mt-3 { margin-top: 24px; }
.mt-4 { margin-top: 36px; }
.mb-0 { margin-bottom: 0; }
.center { text-align: center; }
.hr { height: 1px; background: var(--line); border: none; margin: 24px 0; }
.nowrap { white-space: nowrap; }

/* ---------------- 后台 ---------------- */

.admin-head { display: flex; align-items: center; gap: 16px; margin: 36px 0 8px; flex-wrap: wrap; }
.admin-head h1 { font-size: 24px; font-weight: 620; letter-spacing: -.02em; margin: 0; }
.admin-head .spacer { flex: 1; }

.tabs { display: flex; gap: 4px; border-bottom: 1px solid var(--line); margin: 24px 0 26px; }
.tabs a {
  padding: 10px 15px; font-size: 14.5px; color: var(--ink-3);
  border-bottom: 2px solid transparent; margin-bottom: -1px;
}
.tabs a:hover { color: var(--ink); text-decoration: none; }
.tabs a.active { color: var(--ink); font-weight: 550; border-bottom-color: var(--accent); }

.stat-row { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 14px; margin-bottom: 28px; }
.stat {
  background: var(--surface); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 16px 18px;
}
.stat .k { font-size: 12.5px; color: var(--ink-3); letter-spacing: .03em; }
.stat .v { font-size: 24px; font-weight: 620; letter-spacing: -.02em; margin-top: 3px; font-variant-numeric: tabular-nums; }

/* ---------------- 响应式 ---------------- */

@media (max-width: 640px) {
  .wrap, .wrap-narrow { padding: 0 16px; }
  .hero { padding: 44px 0 24px; }
  header.site .inner { height: 56px; gap: 12px; }
  .who { display: none; }
  .card { padding: 18px 16px; }
  table.tbl { font-size: 13px; }
  table.tbl th, table.tbl td { padding-left: 8px; padding-right: 8px; }
  .section-head { margin: 36px 0 16px; }
}

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; animation: none !important; }
}

/* v2 */