/* Study-notebook direction: warm paper, black ink, a yellow highlighter.
   Green / red are reserved for speech feedback only. */
:root {
  --paper: #f4efe6;
  --card: #fffdf8;
  --ink: #1c1a17;
  --ink-soft: #6b645a;
  --rule: #ddd3c3;
  --marker: #f6d64a;
  --ok: #2f7d4f;
  --miss: #c2412d;
  --hud-bg: #1c1a17;
  --hud-fg: #f4efe6;
  --font-en: 'Newsreader', 'Iowan Old Style', Georgia, serif;
  --font-ui: -apple-system, BlinkMacSystemFont, 'PingFang TC', 'Noto Sans TC', sans-serif;
  --text-hero: clamp(2.4rem, 1.6rem + 4vw, 3.6rem);
  --radius-card: 18px;
  --radius-chip: 999px;
  --gutter: clamp(16px, 4vw, 28px);
  --ease: cubic-bezier(0.16, 1, 0.3, 1);
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root {
    --paper: #171512;
    --card: #221f1b;
    --ink: #f1ebe0;
    --ink-soft: #a59c8e;
    --rule: #3a352e;
    --marker: #d9b52c;
    --ok: #6cc28f;
    --miss: #ef7a64;
    --hud-bg: #2c2822;
    --hud-fg: #f1ebe0;
    color-scheme: dark;
  }
}

* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 16px/1.55 var(--font-ui);
  -webkit-text-size-adjust: 100%;
}
.shell {
  max-width: 680px;
  margin: 0 auto;
  padding: calc(env(safe-area-inset-top, 0px) + 12px) var(--gutter) calc(env(safe-area-inset-bottom, 0px) + 48px);
}
a { color: inherit; }
button, input, textarea { font: inherit; color: inherit; }
:focus-visible { outline: 3px solid var(--marker); outline-offset: 2px; }

/* Home */
.masthead { padding-block: 28px 20px; }
.eyebrow {
  margin: 0 0 8px;
  font-size: 0.75rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-soft);
}
.masthead h1 {
  margin: 0;
  font: 600 var(--text-hero)/1.05 var(--font-en);
  letter-spacing: -0.02em;
}
textarea {
  width: 100%;
  padding: 14px 16px;
  border: 1.5px solid var(--ink);
  border-radius: 14px;
  background: var(--card);
}
.status { margin: 4px 0 0; font-size: 0.9rem; color: var(--ink-soft); min-height: 1.4em; }
.status--error { color: var(--miss); }

.btn {
  display: inline-flex;
  justify-content: center;
  align-items: center;
  min-height: 48px;
  padding: 0 20px;
  border: 1.5px solid var(--ink);
  border-radius: 14px;
  background: transparent;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  transition: transform 150ms var(--ease), background 150ms var(--ease);
}
.btn:active { transform: scale(0.97); }
.btn:disabled { opacity: 0.45; cursor: progress; }
.btn--primary { background: var(--ink); color: var(--paper); }
.btn--ghost { border-color: transparent; color: var(--ink-soft); font-weight: 400; }

.review-cta {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 14px 18px;
  margin-bottom: 32px;
  border-radius: var(--radius-card);
  background: var(--marker);
  color: #1c1a17;
  text-decoration: none;
  font-weight: 600;
  box-shadow: 0 1px 0 rgba(0, 0, 0, 0.08), 0 8px 24px -12px rgba(0, 0, 0, 0.35);
  transition: transform 150ms var(--ease);
}
.review-cta:active { transform: translateY(1px); }
.review-cta--empty { background: var(--card); color: var(--ink-soft); box-shadow: none; border: 1px dashed var(--rule); }
.review-cta__count { font: 600 2rem/1 var(--font-en); }

.section-title {
  margin: 0 0 12px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--rule);
  font-size: 0.8rem;
  letter-spacing: 0.12em;
  color: var(--ink-soft);
}
.lesson-list { list-style: none; margin: 0; padding: 0; display: grid; gap: 4px; }
.lesson-row {
  display: flex;
  gap: 14px;
  align-items: center;
  padding: 10px 0;
  text-decoration: none;
  border-bottom: 1px solid var(--rule);
}
.lesson-row img { border-radius: 8px; flex: none; width: 120px; height: 68px; object-fit: cover; }
.lesson-row__text { display: grid; gap: 2px; min-width: 0; }
.lesson-row strong { font: 600 1.05rem/1.25 var(--font-en); overflow-wrap: anywhere; }
.lesson-row small { color: var(--ink-soft); }
.empty { color: var(--ink-soft); }

/* Lesson */
.topbar {
  display: flex;
  justify-content: space-between;
  padding-block: 8px 12px;
  font-size: 0.95rem;
}
.topbar a { text-decoration: none; font-weight: 600; }
.stage {
  position: sticky;
  top: env(safe-area-inset-top, 0px);
  z-index: 2;
  margin-inline: calc(var(--gutter) * -1);
  padding: 0 var(--gutter) 10px;
  background: var(--paper);
}
.stage__frame {
  aspect-ratio: 16 / 9;
  max-width: 100%;
  border-radius: 14px;
  overflow: hidden;
  background: #000;
}
.stage__frame--mini { max-width: 260px; }
.stage__frame iframe, .stage__frame > div { width: 100%; height: 100%; }
.lesson-head h1 { margin: 12px 0 4px; font: 600 1.6rem/1.15 var(--font-en); }
.lesson-head p { margin: 0 0 16px; color: var(--ink-soft); }

.tabs { display: flex; gap: 6px; padding-top: 10px; }
.tab {
  flex: 1;
  min-height: 42px;
  border: 1.5px solid var(--rule);
  border-radius: 12px;
  background: transparent;
  font-weight: 600;
  color: var(--ink-soft);
  cursor: pointer;
}
.tab[aria-selected='true'] { border-color: var(--ink); background: var(--ink); color: var(--paper); }

.sentences, .phrases, .speaks { list-style: none; margin: 8px 0 0; padding: 0; display: grid; gap: 12px; }
.sentence, .phrase, .speak {
  padding: 16px;
  border-radius: var(--radius-card);
  background: var(--card);
  border: 1px solid var(--rule);
}
.sentence__meta { display: flex; gap: 10px; font-size: 0.78rem; color: var(--ink-soft); margin-bottom: 6px; }
.sentence__no { font-weight: 700; color: var(--ink); }

.reveal {
  display: block;
  width: 100%;
  padding: 6px 0;
  border: 0;
  background: none;
  text-align: left;
  cursor: pointer;
}
.reveal > span[lang] { display: none; }
.reveal--open > span[lang] { display: inline; }
.reveal--open .reveal__hint { display: none; }
.reveal__hint {
  display: inline-block;
  padding: 2px 10px;
  border-radius: 6px;
  border: 1px dashed var(--rule);
  font-size: 0.85rem;
  color: var(--ink-soft);
}
.reveal--en > span[lang] { font: 400 1.3rem/1.4 var(--font-en); }
.reveal--zh > span[lang] { color: var(--ink-soft); }

.chips { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 10px; }
.chip {
  min-height: 38px;
  padding: 0 14px;
  border: 1.5px solid var(--rule);
  border-radius: var(--radius-chip);
  background: transparent;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: transform 150ms var(--ease), border-color 150ms var(--ease);
}
.chip:active { transform: scale(0.95); }
.chip--play { border-color: var(--ink); }
.chip--live { background: var(--marker); border-color: var(--marker); color: #1c1a17; }
.chip[aria-pressed='true'] { border-color: var(--ink); }

.shadow-result:empty { display: none; }
.shadow-result { margin-top: 10px; padding-top: 10px; border-top: 1px dashed var(--rule); }
.heard { margin: 0; color: var(--ink-soft); font-style: italic; }
.heard--error { color: var(--miss); font-style: normal; }
.diff { margin: 0; font: 1.15rem/1.5 var(--font-en); }
.w-ok { color: var(--ok); }
.w-miss { color: var(--miss); text-decoration: underline wavy; text-underline-offset: 4px; }
.score { margin: 4px 0 0; font-size: 0.9rem; }

.phrase__en { margin: 0; font: 600 1.35rem/1.25 var(--font-en); }
.phrase__en::after {
  content: '';
  display: block;
  width: 2.5em;
  height: 6px;
  margin-top: 4px;
  background: var(--marker);
  border-radius: 3px;
}
.phrase__zh { margin: 8px 0 0; }
.phrase__example { margin: 6px 0 0; font: italic 1.05rem/1.4 var(--font-en); color: var(--ink-soft); }

.speak__prompt { margin: 0 0 4px; font-size: 1.1rem; font-weight: 600; }
.speak__phrase { margin: 0 0 10px; font-family: var(--font-en); color: var(--ink-soft); }
.used { margin: 6px 0 0; color: var(--ok); font-weight: 600; min-height: 1.2em; }

.lesson-foot { display: grid; gap: 8px; margin-top: 32px; }

/* Review */
.review { padding-top: 16px; display: grid; gap: 12px; }
.review__prompt { margin: 0; font-size: 1.5rem; font-weight: 600; line-height: 1.35; }
.review__tip { margin: 0; color: var(--ink-soft); font-size: 0.9rem; }
.review__answer { padding: 16px; border-radius: var(--radius-card); background: var(--card); border: 1px solid var(--rule); }
.review__en { margin: 0; font: 400 1.45rem/1.35 var(--font-en); }
.grade { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; margin-top: 16px; }
.review__done { font: 600 1.6rem/1.3 var(--font-en); }

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; }
}

/* ---------- Game layer ---------- */
.hud {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 16px;
  align-items: center;
  padding: 16px;
  margin-bottom: 14px;
  border-radius: var(--radius-card);
  background: var(--hud-bg);
  color: var(--hud-fg);
}
.hud__level { display: flex; gap: 12px; align-items: center; min-width: 0; }
.hud__badge {
  display: grid;
  place-items: center;
  width: 52px;
  height: 52px;
  flex: none;
  border-radius: 14px;
  background: var(--marker);
  color: #1c1a17;
  font: 600 1.5rem/1 var(--font-en);
}
.hud__badge small { font: 700 0.55rem/1 var(--font-ui); letter-spacing: 0.12em; }
.hud__bar-wrap { display: grid; gap: 4px; flex: 1; min-width: 0; }
.hud__bar { height: 8px; border-radius: 4px; background: rgba(255, 255, 255, 0.18); overflow: hidden; }
.hud__bar span {
  display: block;
  height: 100%;
  background: var(--marker);
  transform-origin: left;
  transition: transform 600ms var(--ease);
}
.hud small { opacity: 0.75; font-size: 0.75rem; }
.hud__daily { display: flex; gap: 10px; align-items: center; }
.hud__daily strong, .hud__daily small { display: block; }
.hud__daily strong { font-size: 0.85rem; }
.ring-wrap { position: relative; width: 56px; height: 56px; }
.ring { transform: rotate(-90deg); }
.ring__track { fill: none; stroke: rgba(255, 255, 255, 0.18); stroke-width: 6; }
.ring__fill { fill: none; stroke: var(--marker); stroke-width: 6; stroke-linecap: round; transition: stroke-dashoffset 600ms var(--ease); }
.ring__label { position: absolute; inset: 0; display: grid; place-items: center; font-size: 0.75rem; font-weight: 700; }
.ring-wrap--done .ring__label { color: var(--marker); font-size: 1.1rem; }
@media (max-width: 380px) { .hud { grid-template-columns: 1fr; } }

.lesson-row__score { color: var(--ink) !important; font-weight: 600; }
.how-to {
  margin-top: 28px;
  padding: 14px 16px;
  border: 1px dashed var(--rule);
  border-radius: var(--radius-card);
  color: var(--ink-soft);
}
.how-to strong { color: var(--ink); }
.how-to p { margin: 4px 0; }
.how-to code {
  display: block;
  margin: 6px 0;
  padding: 8px 10px;
  border-radius: 8px;
  background: var(--card);
  color: var(--ink);
  font-size: 0.85rem;
  overflow-wrap: anywhere;
}

.games { display: grid; gap: 10px; margin-bottom: 28px; }
.game-card {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 16px;
  border-radius: var(--radius-card);
  background: var(--card);
  border: 1.5px solid var(--ink);
  text-decoration: none;
  box-shadow: 4px 4px 0 var(--ink);
  transition: transform 150ms var(--ease), box-shadow 150ms var(--ease);
}
.game-card:active { transform: translate(3px, 3px); box-shadow: 1px 1px 0 var(--ink); }
.game-card__icon { font-size: 2rem; }
.game-card__text { flex: 1; display: grid; }
.game-card__text strong { font-size: 1.1rem; }
.game-card__text small { color: var(--ink-soft); }
.game-card__score { font: 600 1.2rem/1 var(--font-en); padding: 6px 10px; border-radius: 10px; background: var(--marker); color: #1c1a17; }

.stage--play .stage__frame--mini { max-width: 200px; margin-inline: auto; }
.dots { display: flex; justify-content: center; gap: 8px; list-style: none; margin: 4px 0 16px; padding: 0; }
.dots li { width: 28px; height: 6px; border-radius: 3px; background: var(--rule); transition: background 300ms var(--ease); }
.dots li.done { background: var(--ink); }
.dots li.now { background: var(--marker); }

.play-item { display: grid; gap: 14px; }
.play-item__ask { margin: 0; text-align: center; color: var(--ink-soft); font-weight: 600; }
.play-item__en { margin: 0; text-align: center; font: 400 1.5rem/1.35 var(--font-en); }
.play-item .reveal { text-align: center; }
.chips--center { justify-content: center; margin-top: 0; }
.btn--play { min-width: 140px; }
.btn.chip--live { background: var(--marker); border-color: var(--marker); color: #1c1a17; }

.tile-row { display: flex; flex-wrap: wrap; gap: 8px; justify-content: center; min-height: 56px; padding: 10px; border-radius: 14px; }
.tile-row--answer { background: var(--card); border: 1.5px dashed var(--rule); align-items: center; }
.tile-row__hint { color: var(--ink-soft); font-size: 0.9rem; }
.tile {
  min-height: 44px;
  padding: 0 14px;
  border: 1.5px solid var(--ink);
  border-radius: 10px;
  background: var(--card);
  font: 400 1.15rem/1 var(--font-en);
  box-shadow: 0 3px 0 var(--ink);
  cursor: pointer;
  transition: transform 120ms var(--ease), box-shadow 120ms var(--ease);
}
.tile:active { transform: translateY(3px); box-shadow: 0 0 0 var(--ink); }
.tile:disabled { cursor: default; }
.tile--ok { border-color: var(--ok); color: var(--ok); box-shadow: 0 3px 0 var(--ok); }
.tile--miss { border-color: var(--miss); color: var(--miss); box-shadow: 0 3px 0 var(--miss); }
.shake { animation: shake 400ms var(--ease); }
@keyframes shake {
  20%, 60% { transform: translateX(-6px); }
  40%, 80% { transform: translateX(6px); }
}

.feedback { display: grid; gap: 10px; }
.feedback:empty { display: none; }
.feedback__title { margin: 0; font-size: 1.15rem; font-weight: 700; text-align: center; }
.feedback__title--miss { color: var(--miss); }
.feedback__zh { margin: 0; text-align: center; color: var(--ink-soft); }

.stars-box { position: relative; text-align: center; }
.stars { margin: 0; font-size: 2.6rem; letter-spacing: 6px; }
.star { color: var(--rule); display: inline-block; }
.star--on { color: var(--marker); text-shadow: 0 2px 0 rgba(0, 0, 0, 0.15); }
.star--new { animation: pop 500ms var(--ease) both; }
.star--new:nth-child(2) { animation-delay: 120ms; }
.star--new:nth-child(3) { animation-delay: 240ms; }
@keyframes pop {
  0% { transform: scale(0.2) rotate(-30deg); opacity: 0; }
  70% { transform: scale(1.3) rotate(8deg); opacity: 1; }
  100% { transform: scale(1) rotate(0); }
}

.feedback, .stars-box, .shadow-result { position: relative; }
.xp-float {
  position: absolute;
  right: 8px;
  top: -8px;
  padding: 4px 10px;
  border-radius: 999px;
  background: var(--ink);
  color: var(--marker);
  font-weight: 800;
  pointer-events: none;
  animation: float-up 1200ms var(--ease) forwards;
}
body > .xp-float { position: fixed; right: 16px; top: calc(env(safe-area-inset-top, 0px) + 16px); }
@keyframes float-up {
  0% { transform: translateY(8px); opacity: 0; }
  20% { transform: translateY(0); opacity: 1; }
  100% { transform: translateY(-28px); opacity: 0; }
}
.banner {
  position: fixed;
  left: 50%;
  top: calc(env(safe-area-inset-top, 0px) + 20px);
  z-index: 10;
  padding: 14px 22px;
  border-radius: 16px;
  background: var(--marker);
  color: #1c1a17;
  font-weight: 800;
  font-size: 1.1rem;
  box-shadow: 0 12px 30px -10px rgba(0, 0, 0, 0.45);
  animation: banner 2200ms var(--ease) forwards;
}
@keyframes banner {
  0% { transform: translate(-50%, -30px); opacity: 0; }
  15%, 80% { transform: translate(-50%, 0); opacity: 1; }
  100% { transform: translate(-50%, -20px); opacity: 0; }
}

.round-end { display: grid; gap: 16px; padding-top: 24px; text-align: center; }
.round-end__xp { margin: 0; font: 600 4rem/1 var(--font-en); }
.round-end__xp small { font-size: 1.2rem; color: var(--ink-soft); }
.round-end .hud { text-align: left; }