:root {
  --bg: #f5f7fb; --card: #ffffff; --primary: #ff7e33; --primary-dark: #f2621a;
  --text: #2b2f36; --muted: #8a94a6; --radius: 14px; --shadow: 0 2px 12px rgba(31,45,61,.08);
}
* { box-sizing: border-box; margin: 0; padding: 0; }
html { -webkit-text-size-adjust: 100%; }
body { font-family: "PingFang SC", "Microsoft YaHei", system-ui, sans-serif; background: var(--bg); color: var(--text); }
#app { max-width: 1080px; margin: 0 auto; padding: 20px 16px 60px; }

/* 顶部 */
.topbar { display: flex; align-items: center; gap: 12px; padding: 6px 0 18px; flex-wrap: wrap; }
.topbar .back { cursor: pointer; color: var(--muted); font-size: 14px; user-select: none; flex-shrink: 0; }
.topbar .back:hover { color: var(--primary); }
.topbar h1 { font-size: 20px; }
.crumb { color: var(--muted); font-size: 13px; margin-bottom: 14px; }

/* 首页: 大标题 */
.hero { text-align: center; padding: 34px 0 30px; }
.hero h1 { font-size: 34px; letter-spacing: 2px; font-weight: 700; }
.hero p { color: var(--muted); font-size: 14px; margin-top: 10px; }
.hero-user { margin-top: 14px; font-size: 12.5px; color: var(--muted); }
.hero-user a { color: var(--primary); cursor: pointer; margin-left: 8px; }
.hero-user a:hover { color: var(--primary-dark); text-decoration: underline; }

/* 登录 */
.login-page { min-height: 82vh; display: flex; align-items: center; justify-content: center; }
.login-card { width: 100%; max-width: 350px; background: var(--card); border-radius: 18px; padding: 34px 26px 22px; box-shadow: 0 10px 40px rgba(31,45,61,.12); text-align: center; }
.login-logo { font-size: 38px; line-height: 1; }
.login-card h1 { font-size: 22px; margin: 12px 0 6px; }
.login-sub { color: var(--muted); font-size: 13px; margin-bottom: 22px; }
.login-card input { width: 100%; padding: 12px 14px; border: 1px solid #e3e8f0; border-radius: 10px; font-size: 15px; margin-bottom: 12px; outline: none; background: #fbfcfe; }
.login-card input:focus { border-color: var(--primary); background: #fff; }
.login-card button { width: 100%; padding: 13px; border: none; border-radius: 10px; background: linear-gradient(135deg, var(--primary), #ffa15c); color: #fff; font-size: 15px; font-weight: 600; cursor: pointer; margin-top: 4px; }
.login-card button:disabled { opacity: .6; cursor: default; }
.login-err { color: #e05252; font-size: 13px; margin-top: 12px; min-height: 18px; }

/* 课程包网格: 左图右文 */
.pkg-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(400px, 1fr)); gap: 14px; }
.pkg-card { display: flex; align-items: center; gap: 16px; background: var(--card); border-radius: var(--radius); box-shadow: var(--shadow); padding: 14px 18px; cursor: pointer; transition: transform .15s, box-shadow .15s, border-color .15s; border: 2px solid transparent; }
.pkg-card:hover { transform: translateY(-2px); box-shadow: 0 8px 22px rgba(31,45,61,.13); border-color: var(--primary); }
.pkg-thumb { width: 92px; height: 92px; border-radius: 12px; overflow: hidden; flex-shrink: 0; display: flex; align-items: center; justify-content: center; font-size: 32px; background: linear-gradient(135deg, #ffe3d0, #ffd0e0); }
.pkg-thumb img { width: 100%; height: 100%; object-fit: cover; display: block; }
.pkg-body { flex: 1; min-width: 0; }
.pkg-card h2 { font-size: 17px; margin-bottom: 8px; }
.pkg-card .meta { color: var(--muted); font-size: 13px; line-height: 1.7; }
.pkg-card .meta b { color: var(--primary-dark); }
.pkg-arrow { color: #ccd4e0; font-size: 24px; flex-shrink: 0; }

/* 课列表 */
.lesson-list { display: flex; flex-direction: column; gap: 10px; }
.lesson-row { display: flex; align-items: center; gap: 14px; background: var(--card); border-radius: 12px; padding: 14px 18px; box-shadow: var(--shadow); cursor: pointer; transition: transform .12s; }
.lesson-row:hover { transform: translateX(4px); }
.lesson-row .no { width: 40px; height: 40px; border-radius: 50%; background: linear-gradient(135deg, var(--primary), #ffb37e); color: #fff; display: flex; align-items: center; justify-content: center; font-weight: 600; flex-shrink: 0; }
.lesson-row .cover { width: 64px; height: 64px; object-fit: contain; border-radius: 10px; background: #fff; flex-shrink: 0; }
.pkg-icon img { width: 100%; height: 100%; object-fit: contain; }
.lesson-row .info { flex: 1; min-width: 0; }
.lesson-row .info .name { font-size: 15px; font-weight: 600; word-break: break-word; }
.lesson-row .info .sub { color: var(--muted); font-size: 12.5px; margin-top: 3px; }
.lesson-row.disabled { opacity: .55; cursor: default; }
.lesson-row.disabled:hover { transform: none; }
.badge { font-size: 11px; padding: 2px 8px; border-radius: 10px; background: #eef1f6; color: var(--muted); flex-shrink: 0; }
.badge.ok { background: #e5f7ec; color: #1ca35d; }
.badge.partial { background: #fff4e0; color: #d98a12; }
.badge.none { background: #f1f2f5; color: #9aa3b2; }

/* 播放页 */
.player-layout { display: grid; grid-template-columns: 1fr 300px; gap: 16px; align-items: start; }
.video-box { position: relative; background: #000; border-radius: 12px; overflow: hidden; }
.video-box video { width: 100%; aspect-ratio: 16/9; display: block; background: #000; }

/* 全屏模式: 原生全屏与 CSS 铺满共用 */
.video-box.fs-mode { position: fixed; inset: 0; z-index: 9999; border-radius: 0; width: 100vw; height: 100vh; }
.video-box.fs-mode video { width: 100%; height: 100%; aspect-ratio: auto; object-fit: contain; }
.video-box:fullscreen { border-radius: 0; }
.video-box:fullscreen video { width: 100%; height: 100%; aspect-ratio: auto; object-fit: contain; }
body.fs-lock { overflow: hidden; }
.fs-bar { position: absolute; left: 0; right: 0; bottom: 0; display: flex; align-items: center; gap: 10px; padding: 14px; background: linear-gradient(transparent, rgba(0,0,0,.78)); }
.fs-bar button, .fs-bar select { background: rgba(255,255,255,.18); color: #fff; border: none; padding: 7px 12px; border-radius: 8px; font-size: 13px; cursor: pointer; }
.fs-bar .fs-time { color: #fff; font-size: 12.5px; font-variant-numeric: tabular-nums; flex-shrink: 0; }
.fs-bar .fs-prog { flex: 1; min-width: 60px; height: 6px; background: rgba(255,255,255,.28); border-radius: 3px; position: relative; cursor: pointer; }
.fs-bar .fs-prog .fill { height: 100%; background: var(--primary); border-radius: 3px; }
.controls { display: flex; align-items: center; gap: 10px; padding: 10px 14px; background: #111; color: #ddd; flex-wrap: wrap; }
.controls button, .controls select { background: #2a2a2a; color: #eee; border: none; padding: 6px 12px; border-radius: 8px; cursor: pointer; font-size: 13px; }
.controls button:hover { background: #3a3a3a; }
.controls .prog { flex: 1; min-width: 80px; height: 5px; background: #333; border-radius: 3px; position: relative; cursor: pointer; }
.controls .prog .fill { height: 100%; background: var(--primary); border-radius: 3px; }
.clip-title { color: #ccc; font-size: 13px; }

/* 侧栏 */
.side-panel { background: var(--card); border-radius: var(--radius); box-shadow: var(--shadow); padding: 14px; max-height: 640px; overflow: auto; }
.side-panel h3 { font-size: 14px; color: var(--muted); margin: 8px 0 6px; }
.tab-chip { display: block; width: 100%; text-align: left; padding: 10px 12px; border-radius: 10px; border: none; background: transparent; cursor: pointer; font-size: 14px; margin-bottom: 4px; color: var(--text); }
.tab-chip:hover { background: #f2f4f8; }
.tab-chip.active { background: #fff1e6; color: var(--primary-dark); font-weight: 600; }
.tab-chip .dot { display: inline-block; width: 8px; height: 8px; border-radius: 50%; background: #d5dae3; margin-right: 8px; flex-shrink: 0; }
.tab-chip .dot.done { background: #1ca35d; }
.clip-item { padding: 8px 12px; font-size: 13px; color: var(--muted); border-left: 2px solid #eee; margin-left: 10px; cursor: pointer; }
.clip-item:hover { color: var(--primary-dark); }

.empty { color: var(--muted); text-align: center; padding: 60px 0; font-size: 14px; }

/* ============ 响应式: Pad (≤900px) ============ */
@media (max-width: 900px) {
  #app { padding: 14px 12px 40px; }
  .player-layout { grid-template-columns: 1fr; }
  .side-panel { max-height: none; }
  .pkg-grid { grid-template-columns: 1fr; gap: 12px; }
  .topbar h1 { font-size: 18px; }
}

/* ============ 响应式: 手机 (≤600px) ============ */
@media (max-width: 600px) {
  #app { padding: 10px 10px 30px; }
  .topbar { gap: 8px; padding: 4px 0 12px; }
  .topbar h1 { font-size: 16px; }
  .topbar .back { font-size: 13px; }

  /* 课程包: 单列, 左图右文 */
  .pkg-grid { grid-template-columns: 1fr; gap: 10px; }
  .pkg-card { padding: 12px 14px; gap: 12px; }
  .pkg-thumb { width: 72px; height: 72px; border-radius: 10px; font-size: 26px; }
  .pkg-card h2 { font-size: 15px; margin-bottom: 6px; }
  .pkg-card .meta { font-size: 12px; }
  .pkg-arrow { font-size: 20px; }
  .hero { padding: 22px 0 20px; }
  .hero h1 { font-size: 26px; }
  .hero p { font-size: 13px; }
  .login-card { padding: 28px 20px 16px; }

  /* 课列表 */
  .lesson-row { padding: 12px 14px; gap: 10px; }
  .lesson-row .no { width: 36px; height: 36px; font-size: 14px; }
  .lesson-row .cover { width: 56px; height: 56px; border-radius: 8px; }
  .lesson-row .info .name { font-size: 14px; }
  .lesson-row .info .sub { font-size: 11.5px; }

  /* 播放器 */
  .controls { gap: 6px; padding: 8px 10px; }
  .controls button, .controls select { padding: 5px 8px; font-size: 12px; }
  .clip-title { font-size: 12px; }
  .controls .prog { min-width: 60px; }

  /* 侧栏 */
  .side-panel { padding: 12px; }
  .tab-chip { padding: 8px 10px; font-size: 13px; }
  .clip-item { padding: 6px 10px; font-size: 12px; }
}

/* 横屏手机优化 */
@media (max-width: 900px) and (orientation: landscape) {
  .video-box video { aspect-ratio: 16/9; max-height: 50vh; }
}