/* ============================================================
   Pinyin Chart - Modern Interactive Pronunciation Learning
   ============================================================ */

/* -- Tone color variables ---------------------------------- */
:root {
  --tone1-color: #e53935;
  --tone1-bg: #ffeaea;
  --tone1-border: #ef9a9a;
  --tone2-color: #f57c00;
  --tone2-bg: #fff3e0;
  --tone2-border: #ffcc80;
  --tone3-color: #2e7d32;
  --tone3-bg: #e8f5e9;
  --tone3-border: #a5d6a7;
  --tone4-color: #1565c0;
  --tone4-bg: #e3f2fd;
  --tone4-border: #90caf9;
  --tone5-color: #757575;
  --tone5-bg: #f5f5f5;
  --tone5-border: #bdbdbd;

  /* Initial group colours for chart column headers */
  --grp-labial:  #f3e5f5;
  --grp-dental:  #e8f5e9;
  --grp-velar:   #e3f2fd;
  --grp-palatal: #fff3e0;
  --grp-sibilant:#fce4ec;
  --grp-retroflex:#ede7f6;
  --grp-none:    #f5f5f5;
}

/* -- Hero section ----------------------------------------- */
.pinyin-hero {
  background: linear-gradient(135deg, #1a237e 0%, #4a148c 50%, #880e4f 100%);
  color: #fff;
  border-radius: 1.25rem;
  padding: 2.5rem 2rem;
  margin-bottom: 2rem;
  position: relative;
  overflow: hidden;
}
.pinyin-hero::before {
  /* subtle ink-wash texture */
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at 70% 50%, rgba(255,255,255,.04) 0%, transparent 70%);
  pointer-events: none;
}
.pinyin-hero h1 { font-weight: 900; letter-spacing: -0.5px; }
.pinyin-hero p  { opacity: .85; }

/* Decorative CJK glyph in the hero */
.pinyin-hero-deco {
  position: absolute;
  right: 1.5rem;
  top: 50%;
  transform: translateY(-50%);
  font-size: 12rem;
  line-height: 1;
  font-weight: 900;
  font-family: 'Noto Serif CJK SC','STSong',serif;
  color: rgba(255,255,255,.06);
  pointer-events: none;
  user-select: none;
  letter-spacing: -.5rem;
}

/* Stat badges in hero */
.pinyin-hero .stat-badge {
  display: inline-flex;
  align-items: center;
  gap: .35rem;
  padding: .35rem .75rem;
  background: rgba(255,255,255,.12);
  border: 1px solid rgba(255,255,255,.2);
  border-radius: .5rem;
  color: rgba(255,255,255,.9);
  font-size: .78rem;
  font-weight: 600;
}

/* -- Tone overview cards ----------------------------------- */
.tone-card {
  border-radius: 1rem;
  border: 2px solid transparent;
  transition: transform .2s, box-shadow .2s;
  cursor: pointer;
}
.tone-card:hover { transform: translateY(-4px); box-shadow: 0 8px 24px rgba(0,0,0,.12); }

.tone-card.tone-1 { border-color: var(--tone1-border); background: var(--tone1-bg); }
.tone-card.tone-2 { border-color: var(--tone2-border); background: var(--tone2-bg); }
.tone-card.tone-3 { border-color: var(--tone3-border); background: var(--tone3-bg); }
.tone-card.tone-4 { border-color: var(--tone4-border); background: var(--tone4-bg); }
.tone-card.tone-5 { border-color: var(--tone5-border); background: var(--tone5-bg); }

.tone-card .tone-number {
  font-size: 2rem; font-weight: 900; line-height: 1;
}
.tone-card.tone-1 .tone-number { color: var(--tone1-color); }
.tone-card.tone-2 .tone-number { color: var(--tone2-color); }
.tone-card.tone-3 .tone-number { color: var(--tone3-color); }
.tone-card.tone-4 .tone-number { color: var(--tone4-color); }
.tone-card.tone-5 .tone-number { color: var(--tone5-color); }

.tone-card .example-word {
  font-size: 1.75rem; font-weight: 700;
}

.tone-card .vn-badge {
  display: inline-block;
  font-size: 0.75rem;
  padding: 0.2rem 0.55rem;
  border-radius: 0.5rem;
  font-weight: 600;
  letter-spacing: .02em;
}
.tone-1 .vn-badge { background: var(--tone1-color); color: #fff; }
.tone-2 .vn-badge { background: var(--tone2-color); color: #fff; }
.tone-3 .vn-badge { background: var(--tone3-color); color: #fff; }
.tone-4 .vn-badge { background: var(--tone4-color); color: #fff; }
.tone-5 .vn-badge { background: var(--tone5-color); color: #fff; }

/* -- Tone SVG Pitch Contour ------------------------------- */
.tone-contour-svg {
  display: block;
  width: 100%;
  max-width: 120px;
  height: 52px;
  margin: 0 auto .5rem;
}
.tone-path {
  fill: none;
  stroke-width: 3;
  stroke-linecap: round;
  stroke-linejoin: round;
}
.tone-1 .tone-path { stroke: var(--tone1-color); }
.tone-2 .tone-path { stroke: var(--tone2-color); }
.tone-3 .tone-path { stroke: var(--tone3-color); }
.tone-4 .tone-path { stroke: var(--tone4-color); }
.tone-5 .tone-path { stroke: var(--tone5-color); }

/* Animated dash-draw effect on the contour line */
.tone-path-animated {
  stroke-dasharray: 200;
  stroke-dashoffset: 200;
  animation: draw-path 1.2s ease forwards;
}
@keyframes draw-path {
  to { stroke-dashoffset: 0; }
}


/* -- Chart controls --------------------------------------- */
.chart-controls {
  display: flex;
  flex-wrap: wrap;
  gap: .5rem;
  align-items: center;
  margin-bottom: 1rem;
}
.chart-search {
  flex: 1 1 180px;
  min-width: 160px;
  max-width: 260px;
}
.tone-filter-btn {
  padding: .3rem .75rem;
  font-size: .82rem;
  font-weight: 600;
  border-radius: .5rem;
  border: 2px solid transparent;
  background: var(--bs-secondary-bg);
  color: var(--bs-body-color);
  cursor: pointer;
  transition: all .15s;
}
.tone-filter-btn.active-t1 { background: var(--tone1-bg); border-color: var(--tone1-border); color: var(--tone1-color); }
.tone-filter-btn.active-t2 { background: var(--tone2-bg); border-color: var(--tone2-border); color: var(--tone2-color); }
.tone-filter-btn.active-t3 { background: var(--tone3-bg); border-color: var(--tone3-border); color: var(--tone3-color); }
.tone-filter-btn.active-t4 { background: var(--tone4-bg); border-color: var(--tone4-border); color: var(--tone4-color); }
.tone-filter-btn.active-t5 { background: var(--tone5-bg); border-color: var(--tone5-border); color: var(--tone5-color); }

/* -- Chart table ------------------------------------------ */
.chart-wrapper {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  border-radius: .75rem;
  border: 1px solid var(--bs-border-color);
  background: var(--bs-body-bg);
}
.pinyin-table {
  border-collapse: separate;
  border-spacing: 2px;
  min-width: 760px;
}
.pinyin-table th {
  position: sticky;
  top: 0;
  background: var(--bs-body-bg);
  z-index: 2;
  padding: .3rem .4rem;
  font-size: .72rem;
  font-weight: 700;
  text-align: center;
  white-space: nowrap;
  border-bottom: 2px solid var(--bs-border-color);
}
.pinyin-table th.final-header {
  position: sticky;
  left: 0;
  z-index: 3;
  background: var(--bs-body-bg);
  border-right: 2px solid var(--bs-border-color);
  min-width: 46px;
}
/* Column colour groups */
.col-none     { background: var(--grp-none) !important; }
.col-labial   { background: var(--grp-labial) !important; }
.col-dental   { background: var(--grp-dental) !important; }
.col-velar    { background: var(--grp-velar) !important; }
.col-palatal  { background: var(--grp-palatal) !important; }
.col-sibilant { background: var(--grp-sibilant) !important; }
.col-retroflex{ background: var(--grp-retroflex) !important; }

.pinyin-table .final-label {
  position: sticky;
  left: 0;
  z-index: 1;
  background: var(--bs-body-bg);
  font-size: .72rem;
  font-weight: 700;
  text-align: center;
  padding: .3rem .4rem;
  border-right: 2px solid var(--bs-border-color);
  white-space: nowrap;
}

/* -- Chart cells ------------------------------------------ */
.pinyin-cell {
  padding: 0;
  text-align: center;
  vertical-align: middle;
}
.pinyin-cell-btn {
  display: block;
  width: 100%;
  min-width: 38px;
  padding: .35rem .2rem;
  background: transparent;
  border: 1px solid transparent;
  border-radius: .4rem;
  cursor: pointer;
  font-size: .82rem;
  font-weight: 600;
  color: var(--bs-body-color);
  transition: background .12s, transform .1s, border-color .12s;
  line-height: 1.15;
  white-space: nowrap;
}
.pinyin-cell-btn:hover {
  background: var(--bs-primary-bg-subtle);
  border-color: var(--bs-primary);
  color: var(--bs-primary);
  transform: scale(1.1);
  z-index: 1;
  position: relative;
}
.pinyin-cell-btn.active {
  background: var(--bs-primary);
  border-color: var(--bs-primary);
  color: #fff;
  box-shadow: 0 2px 8px rgba(var(--bs-primary-rgb), .4);
}
.pinyin-cell-btn.highlighted {
  outline: 2px solid var(--bs-warning);
  outline-offset: 1px;
}
/* Tone-colored tone sub-label inside cell */
.cell-vi {
  display: block;
  font-size: .62rem;
  font-weight: 500;
  opacity: .75;
  line-height: 1;
  margin-top: .1rem;
}
.tone-1 .cell-accent { color: var(--tone1-color); }
.tone-2 .cell-accent { color: var(--tone2-color); }
.tone-3 .cell-accent { color: var(--tone3-color); }
.tone-4 .cell-accent { color: var(--tone4-color); }
.tone-5 .cell-accent { color: var(--tone5-color); }

/* Empty cell */
.pinyin-cell-empty {
  width: 38px;
  min-width: 38px;
  height: 36px;
  background: repeating-linear-gradient(
    135deg,
    transparent,
    transparent 4px,
    rgba(0,0,0,.03) 4px,
    rgba(0,0,0,.03) 8px
  );
  border-radius: .4rem;
}

/* -- Detail modal ----------------------------------------- */
.detail-syllable-big {
  font-size: 4.5rem;
  font-weight: 900;
  line-height: 1;
  letter-spacing: -2px;
  font-family: 'Segoe UI', system-ui, sans-serif;
}

.detail-tone-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: .5rem;
  margin-top: 1rem;
}
.detail-tone-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: .25rem;
  padding: .5rem .3rem;
  border-radius: .6rem;
  cursor: pointer;
  border: 2px solid transparent;
  transition: all .15s;
}
.detail-tone-item:hover { transform: translateY(-2px); }
.detail-tone-item.t1 { background: var(--tone1-bg); border-color: var(--tone1-border); }
.detail-tone-item.t2 { background: var(--tone2-bg); border-color: var(--tone2-border); }
.detail-tone-item.t3 { background: var(--tone3-bg); border-color: var(--tone3-border); }
.detail-tone-item.t4 { background: var(--tone4-bg); border-color: var(--tone4-border); }

.detail-tone-item .tone-accent { font-size: 1.4rem; font-weight: 800; line-height: 1; }
.detail-tone-item.t1 .tone-accent { color: var(--tone1-color); }
.detail-tone-item.t2 .tone-accent { color: var(--tone2-color); }
.detail-tone-item.t3 .tone-accent { color: var(--tone3-color); }
.detail-tone-item.t4 .tone-accent { color: var(--tone4-color); }

.detail-tone-item .tone-vi  { font-size: .8rem; font-weight: 700; color: var(--bs-secondary-color); }
.detail-tone-item .tone-ipa { font-size: .68rem; color: var(--bs-secondary-color); font-style: italic; }

.play-icon { font-size: .9rem; }
.detail-tone-item .play-icon { opacity: .6; }

/* Neutral tone row */
.detail-neutral {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: .5rem .75rem;
  background: var(--tone5-bg);
  border: 2px solid var(--tone5-border);
  border-radius: .6rem;
  margin-top: .5rem;
  cursor: pointer;
}
.detail-neutral .tone-accent { font-size: 1.1rem; font-weight: 700; color: var(--tone5-color); }
.detail-neutral .tone-vi     { font-size: .8rem; color: var(--bs-secondary-color); }

/* -- Audio pulse animation -------------------------------- */
@keyframes audio-pulse {
  0%   { box-shadow: 0 0 0 0 rgba(79, 70, 229, .45); }
  70%  { box-shadow: 0 0 0 8px rgba(79, 70, 229, 0); }
  100% { box-shadow: 0 0 0 0 rgba(79, 70, 229, 0); }
}
.audio-playing {
  animation: audio-pulse .6s ease-out;
}

/* -- Quiz mode -------------------------------------------- */
.quiz-panel {
  background: linear-gradient(135deg, var(--bs-primary-bg-subtle), var(--bs-info-bg-subtle));
  border-radius: 1rem;
  padding: 1.5rem;
  text-align: center;
}
.quiz-syllable-display {
  font-size: 5rem;
  font-weight: 900;
  line-height: 1;
  letter-spacing: -3px;
}
.quiz-option-btn {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-width: 80px;
  padding: .6rem .8rem;
  border-radius: .75rem;
  border: 2px solid var(--bs-border-color);
  background: var(--bs-body-bg);
  font-weight: 700;
  font-size: 1.1rem;
  cursor: pointer;
  transition: all .15s;
  gap: .2rem;
}
.quiz-option-btn:hover { border-color: var(--bs-primary); color: var(--bs-primary); transform:translateY(-2px); }
.quiz-option-btn.correct { background: var(--tone3-bg); border-color: var(--tone3-border); color: var(--tone3-color); }
.quiz-option-btn.wrong   { background: var(--tone1-bg); border-color: var(--tone1-border); color: var(--tone1-color); }
.quiz-score-badge {
  font-size: 1.1rem; font-weight: 800;
}

/* -- Animations for section entry ------------------------- */
.fade-in-up {
  animation: fadeInUp .4s ease both;
}
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* -- Row highlight (section dividers in chart) ------------ */
.chart-section-row td,
.chart-section-row th {
  border-top: 2px solid var(--bs-border-color) !important;
}

/* -- Mobile tweaks ---------------------------------------- */
@media (max-width: 767px) {
  .pinyin-hero { padding: 1.5rem 1rem; }
  .detail-tone-row { grid-template-columns: repeat(2, 1fr); }
  .detail-syllable-big { font-size: 3rem; }
  .quiz-syllable-display { font-size: 3.5rem; }
  .tone-card.tone-5 { display: none; } /* hide neutral on mobile to save space */
}