/* ============================================================
   Shared lesson shell: top bar, act pages, navigation, hook.
   Used by every episode's lesson page (before its own lesson.css).
   ============================================================ */
/* ============ layout shell ============ */
.topbar {
  position: fixed; top: 0; left: 0; right: 0; z-index: 50;
  display: flex; align-items: center; justify-content: space-between; gap: 16px;
  padding: 10px 20px;
  background: linear-gradient(var(--bg) 60%, transparent);
}
.brand { font-size: 18px; color: var(--ink); text-decoration: none; margin: 0; }
.pips { display: flex; gap: 6px; }
.pip {
  width: 14px; height: 14px; border: 2px solid var(--line-2); background: transparent;
  padding: 0; cursor: default;
}
.pip.done { background: var(--gpu-deep); border-color: var(--gpu-deep); cursor: pointer; }
.pip.current { background: var(--gpu); border-color: var(--gpu); box-shadow: 0 0 10px var(--gpu); }

#stage { position: relative; z-index: 1; }

.act {
  display: none;
  min-height: 100vh;
  padding: 84px 20px 110px;
  max-width: 1120px;
  margin: 0 auto;
}
.act.active { display: block; animation: actIn .5s steps(8) both; }
@keyframes actIn { from { opacity: 0; transform: translateY(16px); } to { opacity: 1; transform: none; } }

.act-head { max-width: 760px; margin-bottom: 28px; }
.eyebrow { font-size: 13px; color: var(--muted); margin-bottom: 10px; }
.lede { font-size: 20px; color: #d3d0f5; }

.act-nav {
  position: fixed; bottom: 0; left: 0; right: 0; z-index: 50;
  display: flex; justify-content: space-between; align-items: center;
  padding: 12px 20px;
  background: linear-gradient(transparent, var(--bg) 45%);
  pointer-events: none;
}
.act-nav > * { pointer-events: auto; }
.act-nav .pixel { font-size: 12px; margin: 0; }

.next-row {
  display: flex; align-items: center; justify-content: space-between; gap: 20px; flex-wrap: wrap;
  margin-top: 28px; padding-top: 20px; border-top: 2px dashed var(--line);
}
.next-row p { margin: 0; max-width: 620px; }

.controls { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; margin-top: 16px; }
.controls.center { justify-content: center; }
.lbl { display: block; font-family: var(--font-pixel); font-size: 11px; color: var(--muted); letter-spacing: .04em; }
.tiny { font-size: 13px; margin: 10px 0 0; }
.tiny-h { font-size: 12px; margin: 0 0 8px; }
.small-note { font-size: 14px; }

canvas.screen {
  width: 100%; aspect-ratio: 32 / 18; display: block;
  background: #07060f;
  border: 2px solid var(--line-2);
}

/* ============ ACT 0 hook ============ */
.act[data-act="0"] { max-width: none; padding: 0; position: relative; overflow: hidden; }
.act[data-act="0"].active { display: flex; align-items: center; justify-content: center; }
.hook-bg {
  position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover;
  opacity: .55;
}
.act[data-act="0"]::after {
  content: ""; position: absolute; inset: 0; pointer-events: none;
  background: radial-gradient(ellipse at 50% 55%, rgba(11,10,23,.35), rgba(11,10,23,.92) 75%);
}
.hook-content { position: relative; z-index: 2; max-width: 860px; padding: 100px 24px; text-align: center; }
.hook-lines .hl {
  font-size: clamp(22px, 3.2vw, 34px); line-height: 1.3; margin: 0 0 .55em;
  opacity: 0; transform: translateY(10px); transition: opacity .6s, transform .6s;
}
.hook-lines .hl.big { font-size: clamp(24px, 3.6vw, 40px); }
.hook-lines .hl.show { opacity: 1; transform: none; }
#hook-counter { font-family: var(--font-mono); font-variant-numeric: tabular-nums; white-space: nowrap; }
.hook-cta { margin-top: 36px; display: flex; flex-direction: column; align-items: center; gap: 12px;
  opacity: 0; transition: opacity .6s; }
.hook-cta.show { opacity: 1; }
.hook-cta .btn { font-size: 22px; padding: 16px 30px 14px; }


@media (max-width: 640px) {
  .act { padding: 76px 16px 100px; }
  .lede { font-size: 17px; }
  .pips { display: none; }
}