/* ─── Letter Grid ───────────────────────────────────────────────────────────── */
#letterGrid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(70px, 1fr));
  gap: 10px;
  margin-bottom: 28px;
}

@keyframes lbtn-in {
  from { opacity: 0; transform: scale(.7) translateY(10px); }
  to   { opacity: 1; transform: scale(1) translateY(0); }
}

.letter-btn {
  aspect-ratio: 1;
  border: 3px solid transparent;
  border-radius: 18px;
  background: var(--surface);
  cursor: pointer;
  font-family: inherit;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1px;
  box-shadow: var(--shadow);
  transition: transform .18s, box-shadow .18s, border-color .18s, background .18s;
  animation: lbtn-in .4s ease both;
  position: relative;
  overflow: hidden;
}

/* Coloured top bar */
.letter-btn::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 5px;
  background: var(--lc);
  border-radius: 15px 15px 0 0;
}

.letter-btn:hover {
  transform: translateY(-4px) scale(1.05);
  box-shadow: var(--shadow-lg);
  border-color: var(--lc);
}

.letter-btn.active {
  background: var(--lc);
  border-color: var(--lc);
  box-shadow: 0 6px 20px color-mix(in srgb, var(--lc) 55%, transparent);
  transform: translateY(-4px) scale(1.06);
}

.lbtn-upper {
  font-size: 1.9rem;
  font-weight: 900;
  color: var(--lc);
  line-height: 1;
}
.letter-btn.active .lbtn-upper { color: #fff; }

.lbtn-lower {
  font-size: .95rem;
  font-weight: 700;
  color: color-mix(in srgb, var(--lc) 70%, #888);
  line-height: 1;
}
.letter-btn.active .lbtn-lower { color: rgba(255,255,255,.85); }

/* ─── Detail Panel ──────────────────────────────────────────────────────────── */
#detailPanel {
  background: var(--surface);
  border-radius: 28px;
  box-shadow: var(--shadow-lg);
  padding: 28px 24px;
  margin-bottom: 40px;
  display: none;
}

.detail-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 28px;
  align-items: start;
}

/* ── SVG animation box ─────────────────────────────── */
.svg-wrapper {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 14px;
}

#svgBox {
  width: 100%;
  max-width: 200px;
  aspect-ratio: 100 / 120;
  background: radial-gradient(
    circle at 30% 30%,
    color-mix(in srgb, var(--lc) 14%, white) 0%,
    color-mix(in srgb, var(--lc) 5%, white) 100%
  );
  border-radius: 20px;
  border: 3px solid color-mix(in srgb, var(--lc) 25%, white);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 8px;
  box-shadow: inset 0 2px 8px rgba(0,0,0,.06);
}

.letter-svg {
  width: 100%;
  height: 100%;
}

/* Stroke number guide labels */
.stroke-num {
  opacity: 0;
  pointer-events: none;
}

/* Stroke order count badge */
#strokeCount {
  font-size: .82rem;
  font-weight: 700;
  color: var(--text-sub);
  background: #f5f5f5;
  padding: 4px 12px;
  border-radius: 20px;
}

/* Replay button */
#btnStroke {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 11px 22px;
  background: var(--lc, #9C27B0);
  color: #fff;
  border: none;
  border-radius: 50px;
  font-size: .95rem;
  font-weight: 800;
  font-family: inherit;
  cursor: pointer;
  box-shadow: 0 4px 14px color-mix(in srgb, var(--lc, #9C27B0) 45%, transparent);
  transition: transform .18s, box-shadow .18s;
}
#btnStroke:hover { transform: translateY(-2px); }
#btnStroke::before { content: "✏️"; }

/* ── Info box ──────────────────────────────────────── */
.info-box {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

/* ─── Case Toggle Buttons ───────────────────────────────────────────────────── */
.case-toggle {
  display: flex;
  gap: 8px;
}

.case-btn {
  flex: 1;
  padding: 9px 12px;
  border: 2.5px solid #e0e0e0;
  border-radius: 50px;
  background: #f5f5f5;
  font-size: 1rem;
  font-weight: 800;
  font-family: inherit;
  cursor: pointer;
  color: #888;
  transition: all .2s ease;
}
.case-btn:hover {
  border-color: var(--lc, #9C27B0);
  background: color-mix(in srgb, var(--lc, #9C27B0) 10%, white);
  color: var(--lc, #9C27B0);
}
.case-btn.active {
  background: var(--lc, #9C27B0);
  border-color: var(--lc, #9C27B0);
  color: #fff;
  box-shadow: 0 3px 12px color-mix(in srgb, var(--lc, #9C27B0) 40%, transparent);
}

/* ─── Large Aa display ──────────────────────────────────────────────────────── */
.letter-display {
  display: flex;
  align-items: baseline;
  gap: 6px;
  line-height: 1;
}

#detailUppercase,
#detailLowercase {
  font-weight: 900;
  line-height: 1;
  cursor: pointer;
  border-radius: 10px;
  padding: 2px 6px;
  transition: background .18s, opacity .2s;
}
#detailUppercase:hover,
#detailLowercase:hover {
  background: rgba(0,0,0,.06);
}

#detailUppercase { font-size: 5rem; }
#detailLowercase { font-size: 3.5rem; }

.case-active   { opacity: 1;   text-decoration: underline 4px solid; }
.case-inactive { opacity: 0.3; text-decoration: none; }

.case-sep {
  font-size: 2.5rem;
  color: #ccc;
  font-weight: 300;
  align-self: center;
  user-select: none;
}

.case-hint {
  font-size: .72rem;
  color: var(--text-sub);
  font-weight: 600;
  margin-top: -4px;
}

/* Phonics row */
.phonics-row {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.phonics-label {
  font-size: .72rem;
  font-weight: 700;
  color: var(--text-sub);
  letter-spacing: 1px;
  text-transform: uppercase;
}

#detailPhonics {
  font-size: 1.5rem;
  font-weight: 900;
  font-family: "Courier New", monospace;
  color: #455A64;
}

#detailSound {
  font-size: 1.1rem;
  color: var(--text-sub);
  font-weight: 700;
  margin-top: 2px;
}

/* Example word */
.word-row {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.word-label {
  font-size: .72rem;
  font-weight: 700;
  color: var(--text-sub);
  letter-spacing: 1px;
  text-transform: uppercase;
}

.word-display {
  display: flex;
  align-items: center;
  gap: 10px;
}

#detailEmoji {
  font-size: 2.2rem;
}

.word-text {
  display: flex;
  flex-direction: column;
}

#detailWord {
  font-size: 1.25rem;
  font-weight: 900;
  color: var(--text);
}

#detailWordJa {
  font-size: .82rem;
  color: var(--text-sub);
  font-weight: 600;
}

/* Speech buttons */
.speech-btns {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.btn-speak {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 18px;
  background: #f5f5f5;
  border: 2px solid #e0e0e0;
  border-radius: 50px;
  font-size: .9rem;
  font-weight: 700;
  font-family: inherit;
  cursor: pointer;
  transition: background .18s, border-color .18s, transform .18s;
  text-align: left;
}
.btn-speak:hover {
  background: color-mix(in srgb, var(--lc) 12%, white);
  border-color: var(--lc);
  transform: translateX(3px);
}

/* ─── Alphabet main layout ──────────────────────────────────────────────────── */
.alphabet-main {
  position: relative;
  z-index: 5;
  max-width: 860px;
  margin: 0 auto;
  padding: 24px 16px 60px;
}

/* ─── Responsive ────────────────────────────────────────────────────────────── */
@media (max-width: 560px) {
  .detail-inner {
    grid-template-columns: 1fr;
  }
  .svg-wrapper {
    flex-direction: row;
    align-items: center;
    gap: 16px;
  }
  #svgBox { max-width: 130px; }
  #detailUppercase { font-size: 3.5rem; }
  #detailLowercase { font-size: 2.5rem; }
  #letterGrid { grid-template-columns: repeat(auto-fill, minmax(56px, 1fr)); gap: 7px; }
  .lbtn-upper { font-size: 1.5rem; }
}