/* aishi-course-creator lesson styles. Colour tokens first; slide classes (.kicker .h1 .body .small .psg .stmt .chip .stamp ...) are the SVG vocabulary. */
:root {
  --ink: #1B2433; --muted: #5B6778; --line: #E2E8F0; --bg: #F5F2EB; --paper: #FFFDF8;
  --t: #16A34A; --f: #DC2626; --n: #6D5BD0; --amber: #F59E0B;
  --t-bg: #ECFDF3; --f-bg: #FEF2F2; --n-bg: #F1EEFF;
  --sans: 'Be Vietnam Pro', 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --serif: 'Source Serif 4', Georgia, 'Times New Roman', serif;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--bg); color: var(--ink); font-family: var(--sans); font-size: 17px; line-height: 1.55; }
.wrap { max-width: 1080px; margin: 0 auto; padding: 0 16px; }
.top { background: var(--ink); color: #fff; position: sticky; top: 0; z-index: 20; }
.top-in { display: flex; justify-content: space-between; align-items: center; height: 52px; }
.brand { font-weight: 700; display: flex; align-items: center; gap: 6px; font-size: 15px; }
.dot { width: 10px; height: 10px; border-radius: 50%; display: inline-block; }
.dot.t { background: #4ADE80; } .dot.f { background: #F87171; } .dot.n { background: #A99BFF; }
.top nav a { color: #CBD5E1; text-decoration: none; margin-left: 18px; font-size: 14px; font-weight: 500; }
.top nav a:hover { color: #fff; }
.top nav a.lang { border: 1px solid #475569; border-radius: 999px; padding: 2px 10px; font-weight: 700; }
.top nav a { white-space: nowrap; }

/* ---------- bilingual: elements tagged data-lang show only in that language (html[data-lang] is set by player.js) ---------- */
html[data-lang="vi"] [data-lang="en"], html[data-lang="en"] [data-lang="vi"] { display: none !important; }
.page-title { font-size: clamp(22px, 4vw, 34px); margin: 28px 0 14px; letter-spacing: -.01em; }
.page-title span { color: var(--muted); font-weight: 500; }

/* ---------- stage ---------- */
.stage { position: relative; aspect-ratio: 16 / 9; border-radius: 16px; overflow: hidden; background: var(--paper); box-shadow: 0 10px 30px rgba(27,36,51,.12); }
.slides { position: absolute; inset: 0; }
.slide { position: absolute; inset: 0; width: 100%; height: 100%; opacity: 0; transition: opacity .5s ease; pointer-events: none; }
.slide.active { opacity: 1; }
.start { position: absolute; right: 5%; top: 50%; transform: translateY(-50%); display: flex; align-items: center; gap: 14px; border: 0; cursor: pointer; background: #F59E0B; color: var(--ink); padding: 14px 26px 14px 16px; border-radius: 999px; font: 700 20px var(--sans); box-shadow: 0 8px 24px rgba(0,0,0,.25); }
.start:hover { background: #FBBF24; }
.start-ic { width: 52px; height: 52px; border-radius: 50%; background: var(--ink); color: #fff; display: grid; place-items: center; }
.start-tx { display: flex; flex-direction: column; text-align: left; line-height: 1.2; }
.start-tx small { font-weight: 500; font-size: 14px; }
.start.gone { display: none; }
.caption { min-height: 3.4em; margin: 12px 0 8px; padding: 10px 16px; background: #fff; border-radius: 12px; border: 1px solid var(--line); font-size: 17px; line-height: 1.5; }
.controls { display: flex; align-items: center; gap: 10px; }
.ctl { width: 42px; height: 42px; border-radius: 50%; border: 1px solid var(--line); background: #fff; color: var(--ink); display: grid; place-items: center; cursor: pointer; flex: none; }
.ctl svg { width: 22px; height: 22px; }
.ctl.main { width: 50px; height: 50px; background: var(--ink); color: #fff; border: 0; }
.ctl:focus-visible, .bar:focus-visible, .btn:focus-visible, .opt:focus-visible { outline: 3px solid var(--amber); outline-offset: 2px; }
.bar { flex: 1; height: 10px; background: #E2E8F0; border-radius: 5px; position: relative; cursor: pointer; min-width: 60px; }
.bar-fill { position: absolute; left: 0; top: 0; bottom: 0; width: 0; background: var(--amber); border-radius: 5px; }
.bar-ticks span { position: absolute; top: -3px; width: 2px; height: 16px; background: #94A3B8; border-radius: 1px; }
.time, .count { font-size: 13px; color: var(--muted); font-variant-numeric: tabular-nums; white-space: nowrap; }

/* ---------- slide typography (SVG) ---------- */
.slide text { font-family: var(--sans); }
:where(.slide text:not([fill])) { fill: var(--ink); }
.slide .bg { fill: var(--paper); }
.slide .kicker { font-size: 24px; font-weight: 800; letter-spacing: .12em; fill: #B45309; }
.slide .kicker.light { fill: #FCD34D; }
.slide .h1 { font-size: 50px; font-weight: 800; letter-spacing: -.01em; }
.slide .mega { font-size: 96px; font-weight: 800; letter-spacing: -.02em; }
.slide .sub { font-size: 36px; font-weight: 500; }
.slide .light { fill: #fff; }
.slide .body { font-size: 32px; font-weight: 500; }
.slide .small { font-size: 26px; }
.slide .small:not([fill]) { fill: #475569; }
.slide .b { font-weight: 800; }
.slide .muted { fill: #64748B; }
.slide .en { font-style: normal; }
.slide .chip { font-size: 24px; font-weight: 700; }
.slide .tag { font-size: 18px; font-weight: 800; letter-spacing: .14em; fill: #475569; } /* #475569, not #64748B: contrast fix from a critic review */
.slide .stmt { font-size: 36px; font-weight: 700; }
.slide .stmt.big { font-size: 46px; }
.slide .stmt.sm { font-size: 30px; }
.slide .psg { font-family: var(--serif); font-size: 32px; font-style: italic; }
.slide .psg.sm { font-size: 27px; }
.slide .lab { font-size: 30px; font-weight: 800; fill: #fff; letter-spacing: .04em; }
.slide .icon { font-size: 96px; font-weight: 800; }
.slide .stamp { font-size: 50px; font-weight: 800; letter-spacing: .06em; }
.slide .stamp.sm { font-size: 44px; }
.slide .card { fill: #fff; stroke: var(--line); stroke-width: 2; }
.slide .card.passage { fill: #F1F5F9; stroke: #E2E8F0; }
.slide .flow { stroke: var(--ink); stroke-width: 4; fill: none; }
.slide .arrow { stroke: var(--ink); stroke-width: 4; fill: none; marker-end: url(#ah); }
.slide .arrowline { stroke: #F59E0B; stroke-width: 5; fill: none; stroke-linecap: round; marker-end: url(#ahA); }
.slide .strike { stroke: #DC2626; stroke-width: 8; stroke-linecap: round; fill: none; }

/* ---------- cue-driven animation ---------- */
.slide [data-cue] { opacity: 0; transition: opacity .55s ease var(--d, 0s), transform .6s cubic-bezier(.2,.8,.2,1) var(--d, 0s), stroke-dashoffset .9s ease var(--d, 0s); }
.slide [data-cue].on { opacity: 1; }
.slide .fx-up { transform: translateY(18px); }
.slide .fx-up.on { transform: none; }
.slide .fx-pop { transform-box: fill-box; transform-origin: center; transform: scale(1.8); }
.slide .fx-pop.on { transform: scale(1); }
.slide .fx-draw { stroke-dasharray: 1; stroke-dashoffset: 1; opacity: 1; }
.slide .fx-draw.on { stroke-dashoffset: 0; }
.slide .hl { transform-box: fill-box; transform-origin: left center; transform: scaleX(0); opacity: 1; transition: transform .55s cubic-bezier(.2,.8,.2,1) var(--d, 0s); }
.slide .hl.on { transform: scaleX(1); }
.hl-kw { fill: #BFDBFE; } .hl-sm { fill: #FDE68A; } .hl-bad { fill: #FECACA; } .hl-ok { fill: #BBF7D0; }
.static .slide [data-cue], .static .slide .hl { transition: none !important; }
@media (prefers-reduced-motion: reduce) { .slide [data-cue], .slide .hl { transition: opacity .2s !important; transform: none !important; } }

/* ---------- sections ---------- */
section { margin-bottom: 44px; }
.sec-head { display: flex; justify-content: space-between; align-items: center; gap: 12px; flex-wrap: wrap; margin: 8px 0 14px; }
.sec-head h2 { font-size: 26px; margin: 0; }
.btn { display: inline-flex; align-items: center; gap: 8px; border-radius: 999px; padding: 10px 20px; font: 700 15px var(--sans); cursor: pointer; border: 0; background: var(--ink); color: #fff; text-decoration: none; }
.btn.ghost { background: #fff; color: var(--ink); border: 1px solid var(--line); }
.btn.amber { background: var(--amber); color: var(--ink); }
.btn[disabled] { opacity: .4; cursor: default; }
.ig-page { background: #fff; border-radius: 16px; padding: 12px; box-shadow: 0 6px 20px rgba(27,36,51,.08); max-width: 640px; margin: 0 auto; }
.ig-page svg { width: 100%; height: auto; display: block; }

/* ---------- practice ---------- */
.pr-grid { display: grid; grid-template-columns: 1.05fr 1fr; gap: 18px; align-items: start; }
.pr-grid.no-passage { grid-template-columns: minmax(0, 720px); justify-content: center; }
.passage-box { background: #fff; border: 1px solid var(--line); border-radius: 16px; padding: 18px 22px; position: sticky; top: 64px; max-height: calc(100vh - 80px); overflow: auto; }
.passage-box h3 { margin: 0 0 8px; font: 700 20px var(--serif); }
.passage-box p { font-family: var(--serif); font-size: 18px; line-height: 1.7; margin: 0; }
.sen { border-radius: 4px; padding: 1px 2px; transition: background .3s, box-shadow .3s; }
.passage-box.picking .sen { cursor: pointer; box-shadow: inset 0 -2px 0 #CBD5E1; }
.passage-box.picking .sen:hover { background: #FEF3C7; }
.sen.proof { background: #BBF7D0; box-shadow: inset 0 -3px 0 var(--t); }
.sen.proof-f { background: #FECACA; box-shadow: inset 0 -3px 0 var(--f); }
.sen.near { background: #F1EEFF; text-decoration: underline dashed #6D5BD0; text-decoration-thickness: 2px; text-underline-offset: 4px; }
.sen.wrongpick { background: #FEE2E2; text-decoration: line-through; text-decoration-color: #F87171; }
.qpanel { background: #fff; border: 1px solid var(--line); border-radius: 16px; padding: 20px; }
.qnum { font-size: 13px; font-weight: 800; letter-spacing: .12em; color: #B45309; text-transform: uppercase; }
.qtext { font-size: 21px; font-weight: 700; line-height: 1.4; margin: 6px 0 14px; font-family: var(--serif); }
.why { background: #FEF3C7; border-radius: 12px; padding: 10px 14px; font-size: 15px; margin-bottom: 12px; }
.why b { color: #92400E; }
.opts { display: grid; grid-template-columns: repeat(var(--cols, 3), 1fr); gap: 8px; }
.opts.single { grid-template-columns: 1fr; }
.opts.single .opt { text-align: left; padding: 12px 14px; font-weight: 600; }
.opt { border: 2px solid var(--line); background: #fff; border-radius: 12px; padding: 12px 6px; font: 800 16px var(--sans); cursor: pointer; color: var(--ink); }
.opt:hover:not([disabled]) { border-color: var(--ink); }
.opt[disabled] { cursor: default; }
.opt.tone-t.right { background: var(--t); color: #fff; border-color: var(--t); }
.opt.tone-f.right { background: var(--f); color: #fff; border-color: var(--f); }
.opt.tone-n.right { background: var(--n); color: #fff; border-color: var(--n); }
.opt.tone-x.right { background: var(--ink); color: #fff; border-color: var(--ink); }
.opt.wrong { background: #fff; color: #94A3B8; border-color: #FCA5A5; text-decoration: line-through; }
.opts.locked .opt:not(.right):not(.wrong) { opacity: .45; }
.fb { margin-top: 14px; border-radius: 12px; padding: 14px 16px; font-size: 16px; }
.fb.ok { background: var(--t-bg); border: 1px solid #86EFAC; }
.fb.no { background: var(--f-bg); border: 1px solid #FCA5A5; }
.fb h4 { margin: 0 0 6px; font-size: 17px; }
.fb p { margin: 6px 0; }
.trap { display: inline-block; font-size: 13px; font-weight: 700; background: #FFF7ED; color: #9A3412; border: 1px solid #FDBA74; border-radius: 999px; padding: 3px 10px; margin-top: 4px; }
.nav-row { display: flex; justify-content: flex-end; margin-top: 14px; }
.dots { display: flex; gap: 6px; }
.dots i { width: 14px; height: 14px; border-radius: 50%; background: #E2E8F0; display: inline-block; }
.dots i.cur { box-shadow: 0 0 0 2px var(--ink); }
.dots i.ok { background: var(--t); } .dots i.no { background: var(--f); }
.score { text-align: center; }
.score .big { font-size: 56px; font-weight: 800; line-height: 1; margin: 6px 0; }
.review { text-align: left; list-style: none; padding: 0; margin: 16px 0; font-size: 14px; }
.review li { padding: 8px 0; border-top: 1px solid var(--line); display: grid; grid-template-columns: 22px 1fr; gap: 6px; }
.review .mk.ok { color: var(--t); font-weight: 800; } .review .mk.no { color: var(--f); font-weight: 800; }
.foot { color: var(--muted); font-size: 13px; text-align: center; padding: 10px 0 40px; }

@media (max-width: 760px) {
  body { font-size: 16px; }
  .top nav a { margin-left: 12px; font-size: 13px; }
  .vt-pre { display: none; }
  .brand { font-size: 13px; }
  .stage { border-radius: 10px; }
  .start { right: 3%; top: auto; bottom: 4%; transform: none; padding: 5px; gap: 0; }
  .start-tx { display: none; }
  .start-ic { width: 36px; height: 36px; }
  .start-ic svg { width: 20px; height: 20px; }
  .start-tx small { font-size: 11px; }
  .caption { font-size: 15px; }
  .controls { flex-wrap: wrap; }
  .bar { order: 5; flex-basis: 100%; }
  .count { margin-left: auto; }
  .pr-grid { grid-template-columns: 1fr; }
  .passage-box { position: static; max-height: 44vh; }
  .passage-box p { font-size: 16px; }
  .qtext { font-size: 18px; }
}
@media print {
  .top, #lecture, #practice, .foot, .sec-head .btn { display: none !important; }
  body { background: #fff; }
  .ig-page { box-shadow: none; max-width: none; padding: 0; }
}

/* "your turn" countdown for cues with pause_after (player.js) */
.think { position: absolute; right: 16px; bottom: 16px; display: flex; align-items: center; gap: 10px; padding: 8px 14px;
  background: #1B2433; color: #fff; border-radius: 999px; font-weight: 700; font-size: 15px; opacity: 0; transform: translateY(6px);
  transition: opacity .25s, transform .25s; pointer-events: none; z-index: 3; }
.think.on { opacity: 1; transform: none; }
.think-bar { width: 90px; height: 6px; background: #334155; border-radius: 3px; overflow: hidden; }
.think-bar i { display: block; height: 100%; width: 100%; background: #F59E0B; }

/* day +1 / day +7 review sets (section #review; static HTML, answers in <details>; see lesson-format.md) */
.rv-set { background: var(--paper); border: 1px solid var(--line); border-radius: 16px; padding: 18px 20px; margin-bottom: 20px; }
.rv-set h3 { margin: 0 0 4px; }
.rv-intro { color: var(--muted); margin: 0 0 12px; }
.rv-psg { position: static; max-height: none; margin-bottom: 14px; }
.rv-psg h4 { margin: 0 0 6px; font-family: var(--serif); }
.rv-psg ol { margin: 0; padding-left: 22px; font-family: var(--serif); }
.rv-items { padding-left: 22px; }
.rv-items li { margin-bottom: 12px; }
.rv-stmt { font-weight: 600; margin: 0 0 4px; }
.rv-items details { background: #fff; border: 1px solid var(--line); border-radius: 10px; padding: 6px 12px; }
.rv-items summary { cursor: pointer; color: #1D4ED8; font-weight: 600; }
.rv-ans { display: inline-block; padding: 1px 10px; border-radius: 999px; color: #fff; }
.rv-ans.tone-t { background: #15803D; } .rv-ans.tone-f { background: #DC2626; } .rv-ans.tone-n { background: #6D5BD0; } .rv-ans.tone-x { background: #1B2433; }

/* practice support fading: item.show outlines the sentence to read; the scored pick's "none" button */
.sen.guide { outline: 2px dashed #B45309; outline-offset: 2px; border-radius: 4px; background: #FFF7ED; }
.why-none { justify-content: flex-start; margin: -4px 0 12px; } .why-none .btn { padding: 6px 14px; font-size: 14px; }
.page-gloss { margin: -6px 0 14px; color: var(--muted); font-size: 16px; }

/* replacement reveals: an element with class until-N hides once any data-cue="N" element on the same slide is on,
   so a slide does not pile up every earlier state */
.slide:has([data-cue="2"].on) .until-2, .slide:has([data-cue="3"].on) .until-3, .slide:has([data-cue="4"].on) .until-4,
.slide:has([data-cue="5"].on) .until-5, .slide:has([data-cue="6"].on) .until-6, .slide:has([data-cue="7"].on) .until-7 { visibility: hidden; }