/* BlackNode Academy: video lessons, English and Czech. */
.ac-page { margin: 0; background: var(--bn-bg-page); color: var(--bn-ink); font-family: Inter, system-ui, sans-serif; }
.ac-topbar { position: sticky; top: 0; z-index: 5; display: flex; align-items: center; gap: var(--bn-s-6);
  padding: 12px var(--bn-s-7); background: var(--bn-bg-page); border-bottom: 1px solid var(--bn-border-soft); }
.ac-brand { display: inline-flex; align-items: center; gap: 8px; color: var(--bn-ink); text-decoration: none; font-weight: 600; }
.ac-topbar nav { display: flex; gap: 4px; }
.ac-topbar nav a { padding: 7px 12px; border-radius: var(--bn-r-sm); color: var(--bn-ink-secondary); text-decoration: none; font-size: 14px; }
.ac-topbar nav a:hover { color: var(--bn-ink); background: var(--bn-bg-surface-1); }
.ac-topbar nav a[aria-current="page"] { color: var(--bn-ink); background: var(--bn-bg-surface-2); font-weight: 600; }
.ac-back { margin-left: auto; color: var(--bn-ink-secondary); text-decoration: none; font-size: 14px; display: inline-flex; gap: 4px; align-items: center; }

.ac-main { max-width: 1180px; margin: 0 auto; padding: var(--bn-s-9) var(--bn-s-7) var(--bn-s-12); display: grid; gap: var(--bn-s-9); }
.ac-hero { display: flex; align-items: flex-end; justify-content: space-between; gap: var(--bn-s-6); }
.ac-eyebrow { margin: 0 0 8px; font-size: 13px; font-weight: 600; letter-spacing: .06em; text-transform: uppercase; color: var(--bn-accent-strong); }
.ac-hero h1 { margin: 0; font-family: Geist, Inter, sans-serif; font-size: clamp(30px, 4vw, 44px); line-height: 1.1; letter-spacing: -.02em; }
.ac-lead { margin: 12px 0 0; max-width: 620px; color: var(--bn-ink-secondary); font-size: 17px; line-height: 1.5; }
.ac-lang { display: inline-flex; padding: 3px; gap: 2px; background: var(--bn-bg-surface-2); border: 1px solid var(--bn-border-soft); border-radius: var(--bn-r-md); flex-shrink: 0; }
.ac-lang button { border: 0; background: transparent; padding: 8px 14px; border-radius: 7px; font: inherit; font-size: 14px; color: var(--bn-ink-secondary); cursor: pointer; }
.ac-lang button[aria-checked="true"] { background: var(--bn-bg-page); color: var(--bn-ink); font-weight: 600; box-shadow: var(--bn-shadow-xs, 0 1px 2px rgba(0,0,0,.06)); }
.ac-lang button:focus-visible { outline: 2px solid var(--bn-accent); outline-offset: 2px; }

.ac-stage { display: grid; grid-template-columns: minmax(0, 2.1fr) minmax(260px, 1fr); gap: var(--bn-s-7); align-items: start; }
.ac-player { border-radius: var(--bn-r-lg); overflow: hidden; background: #0f0e0c; border: 1px solid var(--bn-border); aspect-ratio: 16 / 9; }
.ac-player video { display: block; width: 100%; height: 100%; background: #0f0e0c; }
.ac-now__part { margin: 0 0 6px; font-size: 13px; color: var(--bn-ink-muted); font-weight: 500; }
.ac-now__title { margin: 0; font-family: Geist, Inter, sans-serif; font-size: 24px; line-height: 1.2; letter-spacing: -.01em; }
.ac-now__desc { margin: 12px 0 20px; color: var(--bn-ink-secondary); line-height: 1.55; }
.ac-now__nav { display: flex; gap: 8px; flex-wrap: wrap; }

.ac-section-title { margin: 0 0 var(--bn-s-4); font-family: Geist, Inter, sans-serif; font-size: 20px; }
.ac-list { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: var(--bn-s-4); }
.ac-card { display: grid; gap: 10px; width: 100%; text-align: left; padding: 10px; border-radius: var(--bn-r-lg); border: 1px solid var(--bn-border-soft);
  background: var(--bn-bg-surface-1); color: inherit; font: inherit; cursor: pointer; transition: border-color .15s, transform .15s; }
.ac-card:hover { border-color: var(--bn-border-strong); transform: translateY(-1px); }
.ac-card:focus-visible { outline: 2px solid var(--bn-accent); outline-offset: 2px; }
.ac-card[aria-current="true"] { border-color: var(--bn-accent); box-shadow: 0 0 0 3px var(--bn-accent-soft); }
.ac-card__thumb { position: relative; border-radius: var(--bn-r-md); overflow: hidden; aspect-ratio: 16 / 9; background: var(--bn-bg-surface-2); }
.ac-card__thumb img { width: 100%; height: 100%; object-fit: cover; display: block; }
.ac-card__time { position: absolute; right: 8px; bottom: 8px; padding: 2px 7px; border-radius: 6px; background: rgba(15, 14, 12, .78); color: #fff; font-size: 12px; font-variant-numeric: tabular-nums; }
.ac-card__meta { padding: 0 4px 4px; }
.ac-card__num { font-size: 12px; color: var(--bn-ink-muted); }
.ac-card__title { display: block; margin-top: 2px; font-weight: 600; line-height: 1.3; }

.ac-tips { padding: var(--bn-s-7); border-radius: var(--bn-r-xl); background: var(--bn-bg-surface-1); border: 1px solid var(--bn-border-soft); }
.ac-tips__list { margin: 0; padding-left: 22px; display: grid; gap: 10px; line-height: 1.5; color: var(--bn-ink-secondary); }
.ac-tips__list strong { color: var(--bn-ink); }

@media (max-width: 860px) {
  .ac-topbar { padding: 10px 16px; gap: 12px; }
  .ac-topbar nav { display: none; }
  .ac-main { padding: var(--bn-s-7) 16px var(--bn-s-10); gap: var(--bn-s-7); }
  .ac-hero { flex-direction: column; align-items: flex-start; }
  .ac-stage { grid-template-columns: 1fr; }
}