/* ------------------------------------------------------------------
   Flashcard deck template
   Card = coloured border + illustration + 汉字 + pinyin, flips to English.
   ------------------------------------------------------------------ */

:root {
  --paper: #fbf7f2;
  --ink: #2b2724;
  --ink-soft: #6f6862;
  --line: #e6ded4;
  --accent: #8e7bc0;
  --card-radius: 18px;
  --hanzi-font: "Songti SC", "Noto Serif SC", "Source Han Serif SC", "STSong", serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue", Arial, sans-serif;
}

* { box-sizing: border-box; }

html, body { height: 100%; }

body {
  margin: 0;
  font-family: var(--sans);
  color: var(--ink);
  background-color: var(--paper);
  background-image:
    radial-gradient(circle at 12% 8%, rgba(240, 161, 92, .10), transparent 42%),
    radial-gradient(circle at 88% 0%, rgba(142, 123, 192, .10), transparent 40%);
  background-attachment: fixed;
  -webkit-font-smoothing: antialiased;
}

/* ---------- top bar ---------- */

.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px 20px;
  padding: 18px clamp(16px, 4vw, 48px);
  background: rgba(251, 247, 242, .82);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}

.brand { display: flex; flex-direction: column; gap: 2px; margin-right: auto; }
.brand h1 { margin: 0; font-size: 1.05rem; font-weight: 650; letter-spacing: .01em; }
.brand p { margin: 0; font-size: .78rem; color: var(--ink-soft); }

.controls { display: flex; flex-wrap: wrap; align-items: center; gap: 8px; }

.deck-chip,
.btn {
  font: inherit;
  font-size: .78rem;
  line-height: 1;
  padding: 9px 14px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: #fff;
  color: var(--ink);
  cursor: pointer;
  transition: border-color .18s, color .18s, background .18s, transform .18s;
  white-space: nowrap;
}

.btn:hover,
.deck-chip:hover { border-color: #cfc4b6; transform: translateY(-1px); }

.deck-chip[aria-pressed="true"] {
  background: var(--ink);
  border-color: var(--ink);
  color: #fff;
}

.btn[aria-pressed="true"] {
  border-color: var(--accent);
  color: var(--accent);
  box-shadow: inset 0 0 0 1px var(--accent);
}

.btn:focus-visible,
.deck-chip:focus-visible,
.card:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

/* ---------- grid ---------- */

.deck {
  max-width: 1180px;
  margin: 0 auto;
  padding: clamp(20px, 3.5vw, 44px) clamp(16px, 4vw, 48px) 64px;
}

/* Every deck uses the same 5 columns, so a card is the same size in every deck
   (.scratch/inbox/issues/11). A short last row stays left-aligned. */
.grid {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: clamp(14px, 1.8vw, 22px);
}

@media (max-width: 900px) {
  .grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
}

@media (max-width: 620px) {
  .grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 420px) {
  .grid { grid-template-columns: 1fr; }
}

/* ---------- card ---------- */

.card {
  all: unset;
  display: block;
  aspect-ratio: 3 / 4;
  perspective: 1000px;
  cursor: pointer;
  border-radius: var(--card-radius);
}

.card__inner {
  position: relative;
  display: block;
  width: 100%;
  height: 100%;
  transform-style: preserve-3d;
  transition: transform .55s cubic-bezier(.2, .7, .2, 1);
}

.card[aria-pressed="true"] .card__inner { transform: rotateY(180deg); }

.card__face {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 2%;
  padding: 9% 8%;
  border-radius: var(--card-radius);
  border: 2px solid var(--accent);
  background: #fff;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  box-shadow: 0 1px 1px rgba(43, 39, 36, .04), 0 12px 26px -18px rgba(43, 39, 36, .55);
  transition: box-shadow .25s, transform .25s;
  container-type: inline-size;
}

.card:hover .card__front { transform: translateY(-2px); box-shadow: 0 2px 2px rgba(43, 39, 36, .05), 0 18px 34px -18px rgba(43, 39, 36, .45); }

.card__front { gap: 0; }

.card__art {
  flex: 1 1 auto;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  min-height: 0;
  padding-bottom: 4%;
}

.card__art img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  display: block;
}

.card__art--empty::after {
  content: "";
  display: block;
  width: 70%;
  aspect-ratio: 1;
  border: 2px dashed var(--line);
  border-radius: 14px;
}

/* Hanzi scales with the card, not the viewport, so a 3-character word never
   wraps; app.js sets --hanzi-scale from the character count. */
.card__hanzi {
  font-family: var(--hanzi-font);
  font-size: clamp(1.1rem, calc(23cqw * var(--hanzi-scale, 1)), 3.2rem);
  line-height: 1.15;
  letter-spacing: .04em;
  color: #1c1917;
  text-align: center;
  white-space: nowrap;
}

.card__pinyin {
  font-size: clamp(.58rem, 5.4cqw, .78rem);
  letter-spacing: .08em;
  color: var(--ink-soft);
  text-align: center;
  font-variant-numeric: tabular-nums;
  transition: opacity .2s;
  white-space: nowrap;
}

/* meaning printed on the card face (read-aloud style decks) */
.card__english-front {
  margin-top: 5%;
  font-size: .6rem;
  font-weight: 700;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--ink);
  text-align: center;
}

.card--static { cursor: default; }
.card--static:hover .card__front { transform: none; }

/* pinyin is always shown */

/* card back */
.card__back {
  transform: rotateY(180deg);
  background: var(--accent-back, var(--accent));
  border-color: var(--accent-back, var(--accent));
  color: #fff;
  gap: 6%;
}

.card__english {
  font-size: clamp(1.05rem, 2vw, 1.35rem);
  font-weight: 600;
  letter-spacing: .01em;
  text-align: center;
  text-wrap: balance;
}

.card__back .card__hanzi { color: #fff; font-size: clamp(1.2rem, calc(18cqw * var(--hanzi-scale, 1)), 2.2rem); opacity: .95; }
.card__back .card__pinyin { color: rgba(255, 255, 255, .82); }

/* ---------- footer hint ---------- */

.hint {
  margin: 28px auto 0;
  max-width: 1180px;
  padding: 0 clamp(16px, 4vw, 48px);
  font-size: .74rem;
  color: var(--ink-soft);
  text-align: center;
}

.site-foot {
  margin: 10px auto 28px;
  max-width: 1180px;
  padding: 0 clamp(16px, 4vw, 48px);
  font-size: .74rem;
  text-align: center;
}
.site-foot a { color: var(--ink-soft); }

.banner {
  margin: 0 auto 14px;
  max-width: 1180px;
  padding: 8px 14px;
  font-size: .78rem;
  color: var(--ink-soft);
  background: #fff;
  border: 1px dashed var(--line);
  border-radius: 10px;
  text-align: center;
}
.banner[hidden] { display: none; }

/* ---------- reduced motion ---------- */

@media (prefers-reduced-motion: reduce) {
  .card__inner, .card, .btn, .deck-chip, .card__front { transition: none; }
  .card:hover .card__front { transform: none; }
}

/* ---------- optional print layout (3 per row) ---------- */

@media print {
  .topbar, .hint, .site-foot, .banner { display: none; }
  body { background: #fff; }
  .grid { grid-template-columns: repeat(3, 1fr); gap: 8mm; }
  .card { aspect-ratio: 3 / 4; break-inside: avoid; }
  .card__face { box-shadow: none; }
}