/* Lesson page: own top bar, player, tabs, curriculum sidebar */
body.learn { --header-h: 60px; }
.learn-bar { position: sticky; top: 0; z-index: 40; display: flex; align-items: center; gap: 12px; height: var(--header-h); padding-inline: 12px 16px;
  background: var(--surface); border-bottom: var(--edge); }
.learn-bar-title { flex: 1; min-width: 0; display: flex; align-items: center; gap: 18px; }
.learn-bar-title > a { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; font-weight: 850; text-decoration: none; color: var(--heading); }
.learn-progress { display: flex; align-items: center; gap: 10px; flex: none; }
.learn-progress .meter { width: 140px; }
.learn-progress small { color: var(--muted); font-weight: 700; white-space: nowrap; }
.learn-bar-actions { display: flex; align-items: center; gap: 8px; flex: none; }

/* Three parts on one screen: syllabus | the episode | its panel. Each column scrolls on its own. */
.learn-layout { display: grid; grid-template-columns: 400px minmax(0, 1fr) 380px; height: calc(100svh - var(--header-h)); transition: grid-template-columns .35s var(--ease); }
.learn-layout.side-closed { grid-template-columns: 0 minmax(0, 1fr) 380px; }
.learn-side { overflow-y: auto; overflow-x: hidden; padding: 14px; background: var(--bg-2); border-inline-end: var(--edge); }
.side-closed .learn-side { padding: 0; border: 0; visibility: hidden; }
.learn-side-head { display: flex; align-items: center; gap: 10px; padding: 4px 6px 14px; }
.learn-side-head b { color: var(--heading); font-size: 1.05rem; }
.learn-side-head .side-close { margin-inline-start: auto; display: none; }
.learn-side .curriculum details { background: var(--surface); }
.learn-side .curriculum li a, .learn-side .curriculum li > div { font-size: .92rem; }
.learn-stage { min-width: 0; overflow-y: auto; background: var(--bg); }
.learn-panel { overflow-y: auto; padding: 18px; display: flex; flex-direction: column; gap: 14px; background: var(--bg-2); border-inline-start: var(--edge); }
.stage { background: #000; }
.stage-head { padding: 18px clamp(16px, 3vw, 32px) 0; }
.stage-head h1 { margin: 2px 0 0; font-size: clamp(1.25rem, 2.2vw, 1.6rem); }
.reading { padding: 28px clamp(16px, 4vw, 48px) 8px; max-width: 78ch; margin-inline: auto; }
.panel-card { display: grid; gap: 10px; padding: 16px; background: var(--surface); border: var(--edge); border-radius: 16px; box-shadow: var(--pop); }
.panel-card form { margin: 0; }
.done-note { display: flex; align-items: center; gap: 8px; margin: 0; font-weight: 800; color: var(--good); }
.panel-tabs { min-width: 0; }
.side-btn { box-shadow: none; }
.side-btn:hover { box-shadow: none; transform: none; }
.learn-bar-title { flex: 1; min-width: 0; display: flex; align-items: center; gap: 18px; }
.learn-pager { display: flex; justify-content: space-between; gap: 16px; margin: 28px clamp(16px, 3vw, 32px) 40px; padding-top: 22px; border-top: 2px solid var(--border); }
.learn-pager a, .learn-pager button { display: flex; align-items: center; gap: 12px; max-width: 48%; padding: 12px 16px; border: 2px solid var(--border-strong); border-radius: 14px;
  background: none; color: inherit; font: inherit; text-align: start; text-decoration: none; cursor: pointer; transition: border-color .2s, transform .2s var(--ease); }
.learn-pager a:hover, .learn-pager button:hover { border-color: var(--text); transform: translateY(-2px); color: inherit; }
.learn-pager small { display: block; color: var(--muted); font-size: .8rem; }
.learn-pager b { display: block; color: var(--heading); }
.learn-pager .to-next { margin-inline-start: auto; border-color: var(--ink); background: var(--accent); color: #fff; box-shadow: var(--pop); }
.learn-pager .to-next b, .learn-pager .to-next small { color: #fff; }
.quest { display: flex; gap: 12px; align-items: center; padding: 12px 16px; border: var(--edge); border-radius: 14px; background: var(--sun); color: var(--sun-ink);
  text-decoration: none; box-shadow: -3px 3px 0 var(--ink); transition: transform .2s var(--ease), box-shadow .2s; }
.quest:hover { transform: translate(2px, -3px); box-shadow: -6px 6px 0 var(--ink); color: var(--sun-ink); }
.quest b { display: block; }
.quest small { display: block; font-weight: 700; opacity: .8; }
.learn-tabs { display: flex; gap: 2px; overflow-x: auto; margin-bottom: 16px; border-bottom: 2px solid var(--border); scrollbar-width: none; }
.learn-tabs button { flex: none; display: inline-flex; align-items: center; gap: 6px; padding: 9px 12px; border: 0; border-bottom: 3px solid transparent; margin-bottom: -2px;
  background: none; font-weight: 800; font-size: .92rem; color: var(--muted); cursor: pointer; transition: color .2s, border-color .2s; }
.learn-tabs button:hover { color: var(--heading); }
.learn-tabs button[aria-selected="true"] { color: var(--heading); border-bottom-color: var(--accent); }
.learn-tabs .count { padding: 0 7px; border-radius: 999px; background: var(--surface-2); font-size: .74rem; line-height: 1.7; }
.learn-panel .prose { font-size: .95rem; line-height: 1.95; }
.quiz-stage { padding: 26px clamp(16px, 3vw, 40px) 0; max-width: 900px; margin-inline: auto; }
.quiz-head { display: flex; align-items: center; gap: 16px; margin-bottom: 18px; }
.quiz-head h1 { margin: 0; font-size: clamp(1.3rem, 2.4vw, 1.7rem); }
.quiz-head .big-ico, .quiz-gate .big-ico { display: grid; place-items: center; flex: none; width: 58px; height: 58px; border-radius: 18px; border: var(--edge); background: var(--sun); color: var(--sun-ink); }
.quiz-opts { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 8px; }
.quiz-opts .quiz-opt { margin: 0; }
.learn-panel .timer { position: static; justify-self: start; }
.learn-panel .rank-list li a { padding: 8px 12px; }
.quiz-gate { width: min(460px, calc(100% - 32px)); padding: 28px; border: var(--edge); border-radius: 22px; background: var(--surface); color: var(--text); box-shadow: var(--pop-lg); text-align: center; }
.quiz-gate::backdrop { background: rgba(0, 0, 0, .6); backdrop-filter: blur(3px); }
.quiz-gate[open] { animation: card-in .45s var(--spring); }
.quiz-gate .big-ico { margin: 0 auto 12px; }
.quiz-gate h2 { margin-bottom: 6px; }
.quiz-gate p { color: var(--muted); margin: 0; }
.curriculum .soon-row > div, .curriculum li > div[aria-disabled] { color: var(--muted); cursor: not-allowed; }
.curriculum .tag.soon { background: var(--warn-soft); color: var(--warn); }
.curriculum .quiz-row a, .curriculum .quiz-row > div { padding-inline-start: 22px; font-size: .9rem; }
.curriculum .quiz-row a > svg:first-child, .curriculum .quiz-row > div > svg:first-child { color: var(--sun); }

@media (max-width: 1360px) {
  .learn-layout, .learn-layout.side-closed { grid-template-columns: minmax(0, 1fr) 360px; }
  .learn-side { position: fixed; z-index: 45; top: var(--header-h); inset-inline-start: 0; width: min(420px, 92vw); height: calc(100svh - var(--header-h));
    box-shadow: 0 0 60px rgba(0, 0, 0, .5); transition: translate .35s var(--ease); }
  .learn-side-head .side-close { display: inline-flex; }
  .side-closed .learn-side { translate: 100% 0; visibility: hidden; padding: 14px; transition: translate .35s var(--ease), visibility 0s .35s; }
}
@media (max-width: 960px) {
  .learn-layout, .learn-layout.side-closed { display: block; height: auto; }
  .learn-stage, .learn-panel { overflow: visible; }
  .learn-panel { border: 0; border-top: var(--edge); padding: 18px 16px 48px; }
  .learn-bar-title { gap: 10px; }
  .learn-progress { display: none; }
  .quiz-opts { grid-template-columns: minmax(0, 1fr); }
  .learn-pager { flex-direction: column; }
  .learn-pager a, .learn-pager button { max-width: none; }
  .learn-pager .to-next { margin-inline-start: 0; }
}

.player { position: relative; aspect-ratio: 16 / 9; max-height: calc(100svh - var(--header-h) - 40px); margin-inline: auto; background: #000;
  user-select: none; -webkit-user-select: none; overflow: hidden; }
.player video { display: block; width: 100%; height: 100%; background: #000; }
.player:fullscreen { max-height: none; aspect-ratio: auto; width: 100vw; height: 100vh; }
.watermark { position: absolute; z-index: 2; top: 12%; left: 8%; color: rgba(255, 255, 255, .28); font-size: 15px; font-weight: 700;
  pointer-events: none; direction: ltr; transition: top 1.2s ease, left 1.2s ease; text-shadow: 0 1px 2px rgba(0, 0, 0, .4); }
.big-play { position: absolute; z-index: 3; inset: 0; margin: auto; width: 96px; height: 96px; border: var(--edge); border-radius: 50%;
  background: var(--accent); color: #fff; display: grid; place-items: center; cursor: pointer; box-shadow: var(--pop); transition: transform .2s var(--spring), opacity .2s; }
.big-play .icon { fill: currentColor; stroke: none; margin-inline-start: 6px; }
.big-play:hover { transform: scale(1.08); }
.player.playing .big-play { opacity: 0; pointer-events: none; }
.controls { position: absolute; z-index: 4; inset-inline: 0; bottom: 0; display: flex; align-items: center; gap: 6px; padding: 26px 12px 10px;
  background: linear-gradient(transparent, rgba(0, 0, 0, .85)); color: #fff; transition: opacity .25s; }
.player.playing.idle .controls { opacity: 0; }
.player.playing.idle { cursor: none; }
.controls button { width: 40px; height: 40px; display: grid; place-items: center; border: 0; background: transparent; color: #fff; border-radius: 10px; cursor: pointer; }
.controls button:hover { background: rgba(255, 255, 255, .16); }
.controls select { height: 34px; border: 0; border-radius: 10px; background: rgba(255, 255, 255, .16); color: #fff; padding: 0 6px; font-size: 13px; }
.controls select option { color: #000; }
.controls .time { font-size: 13px; min-width: 96px; text-align: center; }
.seek { flex: 1; accent-color: var(--accent); min-width: 60px; }
.player .i-pause, .player.playing .i-play, .player .i-mute, .player.muted .i-vol { display: none; }
.player.playing .i-pause, .player.muted .i-mute { display: block; }
.next-up { position: absolute; z-index: 6; inset-inline-end: 20px; bottom: 76px; display: grid; gap: 4px; width: min(320px, 80%); padding: 18px; border: var(--edge);
  border-radius: 16px; background: var(--surface); color: var(--text); box-shadow: var(--pop-lg); animation: card-in .5s var(--spring); }
.next-up p { margin: 0; font-size: .82rem; color: var(--muted); font-weight: 700; }
.next-up b { color: var(--heading); }
.next-up-actions { display: flex; gap: 8px; margin-top: 10px; }
@media (max-width: 640px) { .controls [data-act="back"], .controls [data-act="fwd"], .controls [data-quality] { display: none; } .controls .time { min-width: 0; } }

.locked { width: 100%; min-height: min(56.25vw, 70svh); display: grid; place-items: center; text-align: center; padding: 24px; color: #fff;
  background: radial-gradient(rgba(255, 255, 255, .06) 1.5px, transparent 1.5px) 0 0 / 22px 22px, #121016; }
.locked > div { display: grid; gap: 12px; justify-items: center; max-width: 520px; }
.locked h2 { color: #fff; font-size: clamp(1.3rem, 2.4vw, 1.8rem); margin: 0; }
.locked p { color: rgba(255, 255, 255, .75); margin: 0; }
.lock-ico { display: grid; place-items: center; width: 72px; height: 72px; border-radius: 22px; background: var(--sun); color: var(--sun-ink); border: 2px solid #000; }

.files { list-style: none; padding: 0; margin: 0; display: grid; gap: 10px; }
.files a { display: flex; gap: 14px; align-items: center; padding: 14px 16px; background: var(--surface); border: 2px solid var(--border-strong); border-radius: 14px; text-decoration: none; }
.files a:hover { border-color: var(--text); }
.files a span:nth-child(2) { flex: 1; font-weight: 700; }
.note-form { display: flex; gap: 8px; margin-bottom: 14px; }
.notes { list-style: none; padding: 0; margin: 0; display: grid; gap: 8px; }
.notes li { display: flex; gap: 14px; align-items: center; padding: 8px 12px; background: var(--surface); border: 2px solid var(--border); border-radius: 12px; }
.notes li span { flex: 1; }
.notes form { margin: 0; }
.note-time { padding: 2px 10px; border: 2px solid var(--ink); border-radius: 999px; background: var(--sun); color: var(--sun-ink); font-weight: 800; cursor: pointer; direction: ltr; }
.threads { display: grid; gap: 12px; }
.thread { background: var(--surface); padding: 18px 20px; border: 2px solid var(--border); border-radius: 16px; }
.thread p { margin-bottom: 8px; }
.thread .who { margin-bottom: 4px; }
.reply { margin-top: 12px; padding: 12px 16px; background: var(--surface-2); border-radius: 12px; }
.reply.staff { background: var(--accent-soft); border-inline-start: 4px solid var(--accent); }
.reply-form summary { cursor: pointer; list-style: none; margin-top: 8px; display: inline-block; }
.reply-form summary::-webkit-details-marker { display: none; }
.reply-form form { margin-top: 10px; gap: 10px; }