/* ═══════════════════════════════════════════
   日本語入門 — 五十音 / 伊呂波歌 学习站
   ═══════════════════════════════════════════ */

:root {
  --ink: #1a1a1a;
  --ink-soft: #4a4a4a;
  --paper: #fbf8f3;
  --paper-deep: #f3eee4;
  --line: #d8d2c4;
  --accent: #8b1a1a;       /* 朱印红 */
  --accent-soft: #c25555;
  --hl: #f5e6c8;            /* 高亮金 */
  --shadow: 0 1px 2px rgba(0,0,0,.04), 0 4px 12px rgba(0,0,0,.04);
  --font-ja: 'Yuji Syuku', 'Hiragino Mincho ProN', 'Songti SC', serif;
  --font-zh: 'Noto Sans HK', 'Noto Sans TC', 'PingFang HK', 'PingFang TC', 'Microsoft JhengHei', 'Hiragino Sans CNS', 'Source Han Sans HC', 'Source Han Sans TC', 'Heiti TC', system-ui, sans-serif;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html, body {
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-zh);
  font-size: 16px;
  line-height: 1.7;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--accent); text-decoration: none; border-bottom: 1px solid var(--accent-soft); }
a:hover { color: var(--accent-soft); }

.muted { color: var(--ink-soft); font-weight: 300; }

/* ═══ 顶部 ═══ */
.site-header {
  text-align: center;
  padding: 48px 24px 24px;
  border-bottom: 1px solid var(--line);
}

.site-title {
  font-family: var(--font-ja);
  font-size: 56px;
  font-weight: 400;
  letter-spacing: 0.15em;
  margin-bottom: 8px;
  color: var(--ink);
}
.site-title .ja { color: var(--accent); }
.site-title .zh { font-size: 36px; color: var(--ink-soft); margin-left: 12px; }

.tabs {
  display: flex;
  justify-content: center;
  gap: 4px;
  margin-top: 28px;
  flex-wrap: wrap;
}
.tab {
  background: transparent;
  border: 1px solid transparent;
  font-family: var(--font-zh);
  font-size: 16px;
  color: var(--ink-soft);
  padding: 10px 22px;
  cursor: pointer;
  border-radius: 4px;
  transition: all 0.15s;
}
.tab:hover { color: var(--ink); background: var(--paper-deep); }
.tab.active {
  color: var(--accent);
  border-bottom: 2px solid var(--accent);
  border-radius: 0;
  font-weight: 500;
}

/* ═══ 子 tab ═══ */
.sub-tabs {
  display: flex;
  gap: 4px;
  justify-content: center;
  margin: 24px 0 12px;
}
.sub-tab {
  background: transparent;
  border: 1px solid var(--line);
  font-family: var(--font-zh);
  font-size: 14px;
  color: var(--ink-soft);
  padding: 6px 18px;
  cursor: pointer;
  border-radius: 999px;
}
.sub-tab.active {
  background: var(--ink);
  color: var(--paper);
  border-color: var(--ink);
}

/* ═══ Page 切换 ═══ */
main {
  max-width: 980px;
  margin: 0 auto;
  padding: 24px 16px 80px;
}
.page { display: none; }
.page.active { display: block; }

.section-title {
  font-family: var(--font-zh);
  font-size: 24px;
  font-weight: 500;
  margin: 32px 0 16px;
  color: var(--ink);
  text-align: center;
  letter-spacing: 0.05em;
}

/* ═══ 五十音 网格 ═══ */
.grid-gojuon {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 6px;
  margin-bottom: 24px;
}
.grid-archaic {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 6px;
  padding: 16px;
}
.grid-youon {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 6px;
  padding: 16px;
  max-width: 600px;
  margin: 0 auto;
}

.kana-cell {
  background: var(--paper-deep);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 18px 8px 12px;
  cursor: pointer;
  text-align: center;
  transition: all 0.12s;
  user-select: none;
  position: relative;
  min-height: 110px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}
.kana-cell:hover {
  background: var(--hl);
  border-color: var(--accent-soft);
  transform: translateY(-1px);
  box-shadow: var(--shadow);
}
.kana-cell.playing {
  background: var(--accent);
  color: var(--paper);
  border-color: var(--accent);
}
.kana-cell.playing .kana-glyph,
.kana-cell.playing .kana-romaji { color: var(--paper); }

.kana-cell.empty {
  background: transparent;
  border: 1px dashed var(--line);
  cursor: default;
  pointer-events: none;
}

.kana-glyph {
  font-family: var(--font-ja);
  font-size: 56px;
  font-weight: 400;
  line-height: 1;
  color: var(--ink);
}
.kana-cell.youon .kana-glyph { font-size: 44px; }

.kana-romaji {
  font-family: var(--font-zh);
  font-size: 12px;
  color: var(--ink-soft);
  margin-top: 4px;
  letter-spacing: 0.1em;
}

/* 字源汉字（左上角小字） */
.kana-etymon {
  position: absolute;
  top: 4px;
  left: 6px;
  font-family: var(--font-ja);
  font-size: 13px;
  color: var(--accent);
  opacity: 0.75;
  line-height: 1;
}
.kana-cell.playing .kana-etymon { color: var(--paper); opacity: 0.9; }

/* 古假名标记 */
.kana-cell.archaic::after {
  content: '古';
  position: absolute;
  top: 4px;
  right: 6px;
  font-size: 10px;
  color: var(--accent);
  font-family: var(--font-ja);
}

details.extra {
  background: transparent;
  margin: 12px 0;
  border-top: 1px solid var(--line);
  padding-top: 16px;
}
details.extra summary {
  cursor: pointer;
  font-family: var(--font-zh);
  font-size: 16px;
  color: var(--ink);
  padding: 8px 0;
  list-style: none;
  font-weight: 500;
}
details.extra summary::before {
  content: '▸ ';
  color: var(--accent);
  display: inline-block;
  transition: transform 0.15s;
}
details.extra[open] > summary::before { transform: rotate(90deg); }

/* ═══ 伊呂波歌 ═══ */
.iroha-controls {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  margin: 16px 0 32px;
}
.btn-play-all {
  background: var(--accent);
  color: var(--paper);
  border: none;
  padding: 10px 24px;
  border-radius: 999px;
  font-family: var(--font-zh);
  font-size: 15px;
  cursor: pointer;
  letter-spacing: 0.05em;
}
.btn-play-all:hover { background: var(--accent-soft); }

.iroha-poem {
  text-align: center;
  margin: 24px 0 48px;
}
.iroha-line {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 4px;
  margin-bottom: 16px;
}
.iroha-char {
  font-family: var(--font-ja);
  font-size: 56px;
  width: 76px;
  height: 90px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  border-radius: 6px;
  transition: all 0.12s;
  position: relative;
  color: var(--ink);
}
.iroha-char:hover { background: var(--hl); }
.iroha-char.playing { background: var(--accent); color: var(--paper); }

.iroha-char.archaic::after {
  content: '古';
  position: absolute;
  bottom: 2px;
  right: 4px;
  font-size: 9px;
  color: var(--accent);
}
.iroha-char.modern::after {
  content: '※';
  position: absolute;
  top: 2px;
  right: 4px;
  font-size: 12px;
  color: var(--accent);
}

.iroha-translation {
  max-width: 560px;
  margin: 48px auto 0;
  padding: 24px;
  background: var(--paper-deep);
  border-left: 3px solid var(--accent);
  border-radius: 4px;
}
.iroha-translation h3 {
  font-family: var(--font-zh);
  font-size: 18px;
  font-weight: 500;
  margin-bottom: 12px;
  color: var(--accent);
}
.iroha-translation p {
  white-space: pre-line;
  font-size: 15px;
  color: var(--ink-soft);
  line-height: 1.9;
}

/* ═══ 日语构成 ═══ */
.prose { max-width: 680px; margin: 0 auto; padding: 24px 8px; }
.prose h2 {
  font-family: var(--font-zh);
  font-size: 26px;
  font-weight: 500;
  text-align: center;
  margin-bottom: 24px;
  margin-top: 16px;
  color: var(--accent);
  letter-spacing: 0.05em;
}
.prose h3 {
  font-family: var(--font-zh);
  font-size: 20px;
  font-weight: 500;
  margin-top: 36px;
  margin-bottom: 12px;
  color: var(--ink);
}
.prose p { margin-bottom: 12px; color: var(--ink-soft); }
.prose strong { color: var(--ink); font-weight: 500; }
.prose ol { margin: 12px 0 12px 24px; color: var(--ink-soft); }
.prose ol li { margin-bottom: 8px; }

.prose .ja-big {
  font-family: var(--font-ja);
  font-size: 28px;
  color: var(--accent);
  margin: 0 6px;
}
.prose .example {
  font-size: 16px;
  background: var(--paper-deep);
  padding: 10px 16px;
  border-radius: 6px;
  margin-top: 8px;
}
.prose .example.big {
  font-family: var(--font-ja);
  font-size: 32px;
  text-align: center;
  padding: 24px;
  line-height: 2.2;
}
.prose .kata-hl { color: var(--accent); }
.prose .kanji-hl { color: #2c5282; }

/* 可点击朗读的日语词 */
.speak {
  cursor: pointer;
  border-bottom: 1px dashed transparent;
  transition: all 0.15s;
  padding: 0 2px;
  border-radius: 3px;
}
.speak:hover {
  background: var(--hl);
  border-bottom-color: var(--accent-soft);
}
.speak.speak-playing {
  background: var(--accent);
  color: var(--paper) !important;
  border-bottom-color: var(--accent);
}
.speak.speak-playing .kata-hl,
.speak.speak-playing .kanji-hl { color: var(--paper) !important; }
.speak::before {
  content: '🔊';
  font-size: 0.5em;
  opacity: 0;
  margin-right: 2px;
  transition: opacity 0.15s;
  vertical-align: super;
}
.speak:hover::before { opacity: 0.6; }
.prose ruby rt { font-size: 12px; color: var(--ink-soft); }
.prose .lede {
  font-size: 17px;
  text-align: center;
  color: var(--ink);
  margin: 0 auto 24px;
  max-width: 580px;
  font-weight: 400;
}
.prose .center { text-align: center; }
.prose hr.rule {
  border: none;
  border-top: 1px solid var(--line);
  margin: 48px auto;
  width: 60%;
  position: relative;
}
.prose hr.rule::after {
  content: '✦';
  position: absolute;
  top: -10px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--paper);
  padding: 0 12px;
  color: var(--accent);
  font-size: 14px;
}
.prose ul {
  margin: 12px 0 16px 24px;
  color: var(--ink-soft);
}
.prose ul li {
  margin-bottom: 8px;
  line-height: 1.85;
}
.prose ul li strong { color: var(--ink); }

/* 术语对齐框 — 給零基礎讀者解釋專業詞 */
.prose .termbox {
  background: #fff7e6;
  border-left: 3px solid var(--accent);
  padding: 18px 22px;
  margin: 24px 0;
  border-radius: 4px;
}
.prose .termbox h4 {
  font-family: var(--font-zh);
  font-size: 15px;
  font-weight: 500;
  color: var(--accent);
  margin-bottom: 8px;
  letter-spacing: 0.05em;
}
.prose .termbox p {
  font-size: 14px;
  color: var(--ink-soft);
  margin-bottom: 8px;
}
.prose .termbox dl {
  margin: 12px 0 0;
}
.prose .termbox dt {
  margin-top: 12px;
  color: var(--ink);
  font-size: 14px;
}
.prose .termbox dt:first-child { margin-top: 0; }
.prose .termbox dd {
  margin-left: 0;
  margin-top: 4px;
  font-size: 14px;
  color: var(--ink-soft);
  line-height: 1.75;
}
.prose .termbox dd strong { color: var(--ink); }

/* ═══ 练习 ═══ */
.practice-controls {
  display: flex;
  gap: 12px;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  margin: 24px 0 32px;
  padding: 16px;
  background: var(--paper-deep);
  border-radius: 8px;
}
.practice-controls label {
  font-size: 14px;
  color: var(--ink-soft);
  display: flex;
  align-items: center;
  gap: 6px;
}
.practice-controls select,
.practice-controls button {
  background: var(--paper);
  border: 1px solid var(--line);
  padding: 6px 14px;
  border-radius: 4px;
  font-family: var(--font-zh);
  font-size: 14px;
  cursor: pointer;
  color: var(--ink);
}
.practice-controls button:hover {
  background: var(--ink);
  color: var(--paper);
  border-color: var(--ink);
}
#btn-random {
  background: var(--accent);
  color: var(--paper);
  border-color: var(--accent);
  font-weight: 500;
}
#btn-random:hover { background: var(--accent-soft); border-color: var(--accent-soft); }

.practice-stage {
  text-align: center;
  margin: 24px 0;
  min-height: 220px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}
.practice-glyph {
  font-family: var(--font-ja);
  font-size: 180px;
  line-height: 1;
  color: var(--ink);
  cursor: pointer;
  user-select: none;
  transition: color 0.15s;
}
.practice-glyph:hover { color: var(--accent); }
.practice-glyph.placeholder {
  font-size: 24px;
  color: var(--ink-soft);
  font-family: var(--font-zh);
}
.practice-romaji {
  font-size: 18px;
  margin-top: 12px;
  letter-spacing: 0.2em;
  min-height: 28px;
}

/* 书写练习 */
.practice-write {
  max-width: 480px;
  margin: 32px auto 0;
  padding: 24px;
  background: var(--paper-deep);
  border-radius: 8px;
  text-align: center;
}
.practice-write h3 {
  font-family: var(--font-zh);
  font-size: 16px;
  font-weight: 500;
  margin-bottom: 16px;
  color: var(--ink);
}
.canvas-wrap {
  position: relative;
  width: 320px;
  height: 320px;
  margin: 0 auto;
  background: var(--paper);
  border: 2px solid var(--line);
  border-radius: 8px;
  overflow: hidden;
}
.canvas-wrap::before,
.canvas-wrap::after {
  content: '';
  position: absolute;
  background: var(--line);
  pointer-events: none;
}
.canvas-wrap::before {
  left: 0; right: 0; top: 50%; height: 1px;
  border-top: 1px dashed var(--line);
  background: transparent;
}
.canvas-wrap::after {
  top: 0; bottom: 0; left: 50%; width: 1px;
  border-left: 1px dashed var(--line);
  background: transparent;
}
.canvas-guide {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-ja);
  font-size: 240px;
  color: rgba(0,0,0,0.08);
  line-height: 1;
  pointer-events: none;
  user-select: none;
  z-index: 0;
}
.canvas-guide.hidden { display: none; }
.canvas-stroke {
  position: absolute;
  inset: 0;
  z-index: 2;
  pointer-events: none;
  display: flex;
  align-items: center;
  justify-content: center;
}
.canvas-stroke svg {
  width: 100%;
  height: 100%;
  max-width: 320px;
  max-height: 320px;
}
.stroke-fallback {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100%;
  color: var(--ink-soft);
  font-family: var(--font-zh);
}
#write-canvas {
  position: relative;
  z-index: 1;
  cursor: crosshair;
  touch-action: none;
}
.canvas-controls {
  display: flex;
  gap: 8px;
  justify-content: center;
  margin-top: 16px;
  flex-wrap: wrap;
}
.canvas-controls button {
  background: var(--paper);
  border: 1px solid var(--line);
  padding: 6px 14px;
  border-radius: 4px;
  font-family: var(--font-zh);
  font-size: 13px;
  cursor: pointer;
  color: var(--ink);
}
.canvas-controls button:hover {
  background: var(--ink);
  color: var(--paper);
  border-color: var(--ink);
}

/* 練習 - 全 50 音 picker */
.practice-picker {
  max-width: 720px;
  margin: 48px auto 0;
  padding: 24px;
  background: var(--paper-deep);
  border-radius: 8px;
}
.practice-picker h3 {
  font-family: var(--font-zh);
  font-size: 16px;
  font-weight: 500;
  margin-bottom: 12px;
  color: var(--ink);
  text-align: center;
}
.practice-picker .sub-tabs { margin: 12px 0 16px; }
.picker-grid {
  display: grid;
  grid-template-columns: repeat(10, 1fr);
  gap: 4px;
  max-width: 600px;
  margin: 0 auto;
}
.picker-cell {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 4px;
  padding: 8px 0;
  cursor: pointer;
  text-align: center;
  font-family: var(--font-ja);
  font-size: 22px;
  line-height: 1;
  color: var(--ink);
  user-select: none;
  transition: all 0.12s;
}
.picker-cell:hover {
  background: var(--hl);
  border-color: var(--accent-soft);
  transform: translateY(-1px);
}
.picker-cell.empty {
  background: transparent;
  border: 1px dashed var(--line);
  pointer-events: none;
}
.picker-cell.active {
  background: var(--accent);
  color: var(--paper);
  border-color: var(--accent);
}
@media (max-width: 640px) {
  .picker-grid { grid-template-columns: repeat(5, 1fr); }
  .picker-cell { font-size: 20px; padding: 6px 0; }
}

/* ═══ 页脚 ═══ */
.site-footer {
  text-align: center;
  padding: 32px 16px;
  border-top: 1px solid var(--line);
  margin-top: 48px;
}
.site-footer p { font-size: 13px; }

/* ═══ 移动 ═══ */
@media (max-width: 640px) {
  .site-title { font-size: 40px; }
  .site-title .zh { font-size: 24px; }
  .kana-glyph { font-size: 40px; }
  .kana-cell { min-height: 88px; padding: 12px 4px 8px; }
  .iroha-char { font-size: 40px; width: 56px; height: 70px; }
  .practice-glyph { font-size: 120px; }
  .canvas-wrap { width: 260px; height: 260px; }
  .canvas-guide { font-size: 200px; }
  .tabs { gap: 0; }
  .tab { padding: 8px 14px; font-size: 14px; }
}