:root {
  --paper: #f5f0e6; --card: #fffdf8; --ink: #17171c; --muted: #6d6a62; --line: #e2dbcc;
  --accent: #e5482d; --accent-ink: #fff; --ok: #1f8a5b; --bad: #c9302c; --soft: #ece5d6;
  --radius: 20px; --shadow: 0 1px 2px rgb(30 25 15 / .05), 0 14px 34px -22px rgb(30 25 15 / .35);
  --display: 'Unbounded', 'Segoe UI', sans-serif;
  --body: 'Onest', 'Segoe UI', system-ui, sans-serif;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper: #131316; --card: #1c1c21; --ink: #f2eee5; --muted: #a09c92; --line: #2e2e35; --soft: #26262c;
    --shadow: 0 16px 34px -24px rgb(0 0 0 / .8);
  }
}
:root[data-theme="dark"] {
  --paper: #131316; --card: #1c1c21; --ink: #f2eee5; --muted: #a09c92; --line: #2e2e35; --soft: #26262c;
  --shadow: 0 16px 34px -24px rgb(0 0 0 / .8);
}
[data-accent="en-advanced"] { --accent: #e5482d; }
[data-accent="en-intermediate"] { --accent: #4a57e0; }
[data-accent="en-extra"] { --accent: #c9820a; }
[data-accent="zh-beginner"] { --accent: #12896f; }

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--paper); color: var(--ink); font: 400 16px/1.55 var(--body); }
button, input { font: inherit; color: inherit; }
button { cursor: pointer; border: 0; background: none; }
a { color: inherit; text-decoration: none; }
h1, h2, h3 { font-family: var(--display); font-weight: 700; line-height: 1.15; margin: 0; letter-spacing: -.01em; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; border-radius: 6px; }

.wrap { max-width: 1160px; margin: 0 auto; padding: 0 24px 80px; }
.top { display: flex; align-items: center; justify-content: space-between; padding: 22px 0 30px; gap: 16px; }
.brand { font: 800 19px var(--display); display: flex; align-items: center; gap: 10px; }
.brand i { width: 30px; height: 30px; border-radius: 9px; background: var(--accent); color: #fff; font-style: normal; display: grid; place-items: center; font-size: 15px; }
.top nav { display: flex; gap: 6px; align-items: center; }
.top nav a, .top nav button { padding: 8px 14px; border-radius: 999px; color: var(--muted); font-weight: 500; font-size: 15px; }
.top nav a:hover, .top nav button:hover { background: var(--soft); color: var(--ink); }
.badge { background: var(--accent); color: #fff; border-radius: 999px; font-size: 12px; padding: 1px 7px; margin-left: 4px; font-weight: 600; }

.btn { display: inline-flex; align-items: center; justify-content: center; gap: 8px; padding: 13px 22px; border-radius: 14px; font-weight: 600; background: var(--accent); color: var(--accent-ink); transition: transform .12s, filter .12s; }
.btn:hover { filter: brightness(1.07); }
.btn:active { transform: scale(.98); }
.btn.ghost { background: var(--soft); color: var(--ink); }
.btn:disabled { opacity: .45; cursor: default; filter: none; }

/* Login */
.login { min-height: 100vh; display: grid; place-items: center; padding: 24px; }
.login form { width: 100%; max-width: 400px; background: var(--card); padding: 36px; border-radius: 26px; box-shadow: var(--shadow); display: grid; gap: 16px; }
.login h1 { font-size: 26px; }
.login p { margin: 0; color: var(--muted); }
.field { width: 100%; padding: 14px 16px; border-radius: 14px; border: 1.5px solid var(--line); background: var(--paper); }
.field:focus { outline: none; border-color: var(--accent); }
.err { color: var(--bad); font-size: 14px; min-height: 20px; }

/* Home */
.hero { display: grid; grid-template-columns: 1.5fr 1fr; gap: 18px; margin-bottom: 34px; }
.panel { background: var(--card); border-radius: var(--radius); padding: 28px; box-shadow: var(--shadow); }
.hero .continue { background: var(--ink); color: var(--paper); display: flex; flex-direction: column; justify-content: space-between; min-height: 240px; padding: 34px; }
.hero .continue .eyebrow { color: color-mix(in srgb, var(--paper) 62%, transparent); }
.hero h1 { font-size: clamp(26px, 3.6vw, 40px); margin: 8px 0 22px; }
.eyebrow { font-size: 13px; font-weight: 600; letter-spacing: .06em; text-transform: uppercase; color: var(--muted); }
.stats { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.stat { background: var(--card); border-radius: var(--radius); padding: 20px; box-shadow: var(--shadow); display: flex; flex-direction: column; justify-content: space-between; }
.stat b { font: 700 32px var(--display); }
.stat span { color: var(--muted); font-size: 14px; }
.section-title { font-size: 22px; margin: 0 0 18px; }
.courses { display: grid; grid-template-columns: repeat(2, 1fr); gap: 18px; }
.course { position: relative; background: var(--card); border-radius: var(--radius); padding: 26px; box-shadow: var(--shadow); display: flex; flex-direction: column; gap: 18px; min-height: 212px; overflow: hidden; transition: transform .16s; }
.course:hover { transform: translateY(-3px); }
.course .glyph { position: absolute; right: -6px; top: -26px; font: 800 130px var(--display); color: var(--accent); opacity: .13; pointer-events: none; }
.course h3 { font-size: 21px; max-width: 80%; }
.course .meta { color: var(--muted); font-size: 14px; }
.bar { height: 8px; border-radius: 99px; background: var(--soft); overflow: hidden; }
.bar > i { display: block; height: 100%; background: var(--accent); border-radius: 99px; transition: width .4s; }
.course .foot { margin-top: auto; display: grid; gap: 8px; }
.course .foot small { color: var(--muted); }

/* Course page */
.course-head { margin-bottom: 26px; }
.course-head h1 { font-size: clamp(26px, 4vw, 40px); margin: 6px 0 16px; }
.lessons { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 12px; }
.lesson-card { background: var(--card); border-radius: 16px; padding: 16px 18px; display: flex; gap: 14px; align-items: center; box-shadow: var(--shadow); border: 1.5px solid transparent; transition: border-color .15s; }
.lesson-card:hover { border-color: var(--accent); }
.num { flex: none; width: 42px; height: 42px; border-radius: 12px; display: grid; place-items: center; font: 700 14px var(--display); background: var(--soft); }
.lesson-card.progress .num { background: color-mix(in srgb, var(--accent) 18%, var(--card)); color: var(--accent); }
.lesson-card.done .num { background: var(--ok); color: #fff; }
.lesson-card b { display: block; font-weight: 600; line-height: 1.3; }
.lesson-card small { color: var(--muted); }

/* Lesson page */
.crumb { color: var(--muted); font-size: 14px; }
.crumb a:hover { color: var(--ink); }
.lesson-head { margin: 6px 0 20px; }
.lesson-head h1 { font-size: clamp(24px, 3.4vw, 36px); margin-top: 6px; }
.lesson-head p { color: var(--muted); margin: 10px 0 0; max-width: 720px; }
.steps { display: flex; gap: 8px; margin-bottom: 22px; overflow-x: auto; padding-bottom: 4px; }
.step { flex: none; display: flex; align-items: center; gap: 9px; padding: 11px 18px; border-radius: 14px; background: var(--card); font-weight: 600; color: var(--muted); box-shadow: var(--shadow); }
.step.active { background: var(--ink); color: var(--paper); }
.step .dot { width: 20px; height: 20px; border-radius: 50%; display: grid; place-items: center; font-size: 12px; background: var(--soft); color: var(--muted); }
.step.complete .dot { background: var(--ok); color: #fff; }

.study { display: grid; grid-template-columns: minmax(0, 1fr) 350px; gap: 18px; align-items: start; }
.reader { background: var(--card); border-radius: var(--radius); box-shadow: var(--shadow); overflow: hidden; }
.reader-bar { display: flex; align-items: center; gap: 8px; padding: 10px 14px; border-bottom: 1px solid var(--line); flex-wrap: wrap; }
.reader-bar .count { font-weight: 600; font-variant-numeric: tabular-nums; margin: 0 6px; }
.icon-btn { min-width: 38px; height: 38px; padding: 0 10px; border-radius: 11px; background: var(--soft); font-weight: 600; font-size: 14px; display: inline-flex; align-items: center; justify-content: center; }
.icon-btn:hover { filter: brightness(.96); }
.icon-btn.on { background: #e11d1d; color: #fff; }
.spacer { flex: 1; }
.page-stage { position: relative; background: var(--soft); display: flex; justify-content: center; }
.page-holder { position: relative; line-height: 0; max-width: 100%; }
.page-holder img { width: 100%; max-width: 860px; height: auto; display: block; }
.page-holder.filter::after { content: ''; position: absolute; inset: 0; background: #ff2a2a; mix-blend-mode: multiply; pointer-events: none; }
.hint { font-size: 13px; color: var(--muted); padding: 10px 16px; border-top: 1px solid var(--line); }

.side { position: sticky; top: 16px; display: grid; gap: 14px; }
.player { background: var(--ink); color: var(--paper); border-radius: var(--radius); padding: 20px; display: grid; gap: 12px; }
.player .now { font-weight: 600; }
.player .time { font-size: 13px; opacity: .7; font-variant-numeric: tabular-nums; display: flex; justify-content: space-between; }
.player input[type=range] { width: 100%; accent-color: var(--accent); }
.controls { display: flex; align-items: center; justify-content: space-between; gap: 6px; }
.controls button { padding: 7px 10px; border-radius: 10px; font-weight: 600; font-size: 14px; color: inherit; }
.controls button:hover { background: rgb(255 255 255 / .12); }
.controls .play { width: 52px; height: 52px; border-radius: 50%; background: var(--accent); color: #fff; font-size: 18px; }
.controls .play:hover { background: var(--accent); filter: brightness(1.1); }
.tracks { background: var(--card); border-radius: var(--radius); box-shadow: var(--shadow); padding: 10px; max-height: 46vh; overflow: auto; }
.tracks h3 { font: 600 13px var(--body); color: var(--muted); text-transform: uppercase; letter-spacing: .05em; padding: 8px 10px; }
.track { width: 100%; display: flex; justify-content: space-between; align-items: center; gap: 10px; padding: 10px 12px; border-radius: 11px; text-align: left; font-size: 15px; }
.track:hover { background: var(--soft); }
.track.active { background: color-mix(in srgb, var(--accent) 16%, var(--card)); font-weight: 600; }
.track small { color: var(--muted); font-variant-numeric: tabular-nums; }
.track.heard small::before { content: '✓ '; color: var(--ok); font-weight: 700; }

.video-box { background: #000; border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow); line-height: 0; }
.video-box video { width: 100%; display: block; aspect-ratio: 16/9; }
.grammar { display: grid; gap: 12px; margin-top: 18px; }
.grammar .panel h3 { font-size: 17px; margin-bottom: 10px; }
.grammar .panel p { margin: 6px 0; }
.ex { color: var(--muted); }
.ex b { color: var(--ink); }
.empty { padding: 40px; text-align: center; color: var(--muted); }

/* Flashcards */
.flash { max-width: 560px; margin: 0 auto; display: grid; gap: 16px; }
.card3d { background: var(--card); border-radius: 26px; box-shadow: var(--shadow); padding: 44px 30px; min-height: 280px; display: flex; flex-direction: column; align-items: center; justify-content: center; text-align: center; gap: 10px; width: 100%; }
.card3d .word { font: 700 clamp(26px, 5vw, 38px) var(--display); }
.card3d .ipa { color: var(--muted); }
.card3d .tr { font-size: 22px; font-weight: 600; color: var(--accent); }
.flash .row { display: flex; gap: 10px; }
.flash .row .btn { flex: 1; }
.flash .progress-line { display: flex; justify-content: space-between; color: var(--muted); font-size: 14px; }

/* Quiz */
.quiz { max-width: 720px; margin: 0 auto; }
.quiz .bar { margin-bottom: 20px; }
.q { background: var(--card); border-radius: 26px; box-shadow: var(--shadow); padding: 32px; display: grid; gap: 18px; }
.q .prompt { font-size: 21px; font-weight: 600; line-height: 1.35; }
.q .sub { color: var(--muted); font-size: 15px; margin-top: -10px; }
.opts { display: grid; gap: 10px; }
.opt { text-align: left; padding: 14px 18px; border-radius: 14px; border: 1.5px solid var(--line); font-weight: 500; }
.opt:hover:not(:disabled) { border-color: var(--accent); }
.opt.right { background: color-mix(in srgb, var(--ok) 15%, var(--card)); border-color: var(--ok); }
.opt.wrong { background: color-mix(in srgb, var(--bad) 13%, var(--card)); border-color: var(--bad); }
.opt:disabled { cursor: default; }
.chips { display: flex; flex-wrap: wrap; gap: 8px; min-height: 48px; }
.chips.answer { border-bottom: 2px solid var(--line); padding-bottom: 10px; }
.chip { padding: 9px 15px; border-radius: 11px; background: var(--soft); font-weight: 500; }
.chips.answer .chip { background: var(--ink); color: var(--paper); }
.match { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
.match .col { display: grid; gap: 8px; align-content: start; }
.opt.picked { border-color: var(--accent); background: color-mix(in srgb, var(--accent) 12%, var(--card)); }
.feedback { border-radius: 14px; padding: 14px 16px; font-size: 15px; }
.feedback.ok { background: color-mix(in srgb, var(--ok) 14%, var(--card)); }
.feedback.no { background: color-mix(in srgb, var(--bad) 12%, var(--card)); }
.result { text-align: center; padding: 44px 30px; }
.result .score { font: 800 66px var(--display); color: var(--accent); }
.result .score.pass { color: var(--ok); }
.result p { color: var(--muted); }
.next-row { display: flex; gap: 10px; justify-content: center; flex-wrap: wrap; margin-top: 16px; }
.lesson-foot { display: flex; justify-content: space-between; gap: 10px; margin-top: 26px; flex-wrap: wrap; }

@media (max-width: 900px) {
  .hero, .courses { grid-template-columns: 1fr; }
  .study { grid-template-columns: 1fr; }
  .side { position: static; order: -1; }
  .tracks { max-height: 220px; }
}
@media (max-width: 520px) {
  .wrap { padding: 0 16px 60px; }
  .q { padding: 22px; }
  .match { gap: 6px; }
  .top nav a, .top nav button { padding: 7px 9px; font-size: 14px; }
}
@media (prefers-reduced-motion: reduce) { * { transition: none !important; } }