/* CSC workshop summary-video pages — index + per-video. Screen only. */
:root {
  --bg: #fdfbf6;
  --surface: #ffffff;
  --text: #1c1917;
  --text-sub: #57534e;
  --text-muted: #78716c;
  --border: #e7e2d8;
  --border-strong: #d6cfbe;
  --accent: #d4541c;
  --accent-soft: #fef3ec;
  --green: #2d6a4f;
  --green-soft: #ecf6f0;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --shadow-sm: 0 1px 2px rgba(28, 25, 23, 0.05);
  --shadow-md: 0 4px 12px rgba(28, 25, 23, 0.08);
  --font-zh: "PingFang SC", "Noto Sans SC", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  --font-en: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, "Helvetica Neue", Arial, sans-serif;
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-en);
  font-size: 18px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}
body.zh .en { display: none; }
body:not(.zh) .zh { display: none; }
body.zh { font-family: var(--font-zh); }
a { color: inherit; }

/* nav bar */
.vid-bar {
  display: flex; align-items: center; justify-content: space-between;
  gap: 16px; padding: 16px 24px;
  border-bottom: 1px solid var(--border); background: var(--surface);
  position: sticky; top: 0; z-index: 10;
}
.vid-bar a { text-decoration: none; font-weight: 600; color: var(--text-sub); }
.vid-bar a:hover { color: var(--accent); }
.vid-bar .actions { display: flex; gap: 10px; }
.vid-bar button {
  font: inherit; font-weight: 600; cursor: pointer;
  background: var(--surface); color: var(--text-sub);
  border: 1px solid var(--border-strong); border-radius: var(--radius-sm);
  padding: 6px 14px;
}
.vid-bar button:hover { border-color: var(--accent); color: var(--accent); }

.vid-wrap { max-width: 1040px; margin: 0 auto; padding: 36px 24px 80px; }
h1 { font-size: 34px; font-weight: 800; letter-spacing: -0.01em; margin: 0 0 18px; line-height: 1.15; }
.intro-banner {
  background: var(--green-soft); border: 1px solid var(--border);
  border-left: 4px solid var(--green); border-radius: var(--radius-md);
  padding: 16px 20px; margin-bottom: 32px; font-size: 16px; color: var(--text-sub);
}

/* index grid */
.vid-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 22px;
  align-items: start;
}
.vid-card {
  display: flex; flex-direction: column; text-decoration: none;
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-lg); overflow: hidden;
  box-shadow: var(--shadow-sm); transition: box-shadow .15s, transform .15s;
}
.vid-card:hover { box-shadow: var(--shadow-md); transform: translateY(-2px); border-color: var(--border-strong); }
.vid-card img { width: 100%; height: auto; display: block; background: var(--bg); border-bottom: 1px solid var(--border); }
.vc-body { padding: 16px 18px 18px; display: flex; flex-direction: column; gap: 6px; flex: 1; }
.vc-num { font-size: 12px; font-weight: 700; letter-spacing: 0.06em; text-transform: uppercase; color: var(--accent); }
.vc-title { font-size: 20px; font-weight: 700; margin: 0; line-height: 1.25; }
.vc-meta { margin-top: auto; padding-top: 8px; font-size: 14px; color: var(--text-muted); }
.vc-play { display: inline-flex; align-items: center; gap: 6px; font-weight: 600; color: var(--green); font-size: 15px; }

/* featured (first) — spans two columns, keeps the column layout (no flex-row stretch) */
.vid-card--featured { grid-column: span 2; }
.vid-card--featured .vc-body { padding: 22px 26px; gap: 8px; }
.vid-card--featured .vc-title { font-size: 28px; }
.vc-badge { align-self: flex-start; background: var(--accent-soft); color: var(--accent); font-size: 12px; font-weight: 700; padding: 3px 10px; border-radius: 999px; }
@media (max-width: 680px) { .vid-card--featured { grid-column: auto; } }

/* per-video stage */
.vid-stage { max-width: 900px; margin: 0 auto; }
.vid-num { font-size: 13px; font-weight: 700; letter-spacing: 0.06em; text-transform: uppercase; color: var(--accent); margin-bottom: 6px; }
.vid-stage h1 { font-size: 30px; margin-bottom: 20px; }
.vid-stage video {
  width: 100%; aspect-ratio: 16 / 9; display: block; background: #1c1917;
  border-radius: var(--radius-lg); box-shadow: var(--shadow-md); border: 1px solid var(--border);
}
.vid-meta { margin-top: 14px; font-size: 15px; color: var(--text-muted); }
.vid-foot {
  margin-top: 28px; display: flex; flex-wrap: wrap; align-items: center; gap: 24px;
  border-top: 1px solid var(--border); padding-top: 24px;
}
.vid-qr-block { display: flex; align-items: center; gap: 16px; }
.vid-qr-block .qr-cap { font-size: 15px; font-weight: 600; color: var(--text-sub); max-width: 220px; }
.vid-qr { width: 104px; height: 104px; background: #fff; padding: 6px; border: 1px solid var(--border); border-radius: var(--radius-sm); }
.vid-qr img, .vid-qr canvas { display: block; width: 100% !important; height: 100% !important; }
.vid-lesson-link {
  margin-left: auto; text-decoration: none; font-weight: 600; color: var(--green);
  border: 1px solid var(--border-strong); border-radius: var(--radius-sm); padding: 10px 18px;
}
.vid-lesson-link:hover { border-color: var(--green); background: var(--green-soft); }