:root {
  --bg: #faf8f4;
  --ink: #1c1c1c;
  --accent: #2b5d8c;
  --accent-ink: #ffffff;
  --border: #d8d2c6;
  --highlight: #ff8a3d;
  --error-bg: #fdecea;
  --error-ink: #8a1f11;
}

/* 讓 hidden 屬性一定生效，不被各元件的 display 設定蓋掉 */
[hidden] {
  display: none !important;
}

* {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
  max-width: 100%;
  overflow-x: hidden;
}

body {
  background: var(--bg);
  color: var(--ink);
  font-family: -apple-system, "PingFang TC", "Noto Sans TC", "Microsoft JhengHei", sans-serif;
  font-size: 18px;
  line-height: 1.5;
  padding-bottom: 1rem;
}

h1 {
  font-size: 1.4rem;
  margin: 0 0 0.5rem 0;
}

.topbar {
  padding: 1rem;
  border-bottom: 1px solid var(--border);
  background: #fff;
}

.selectors {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem;
}

.donate-link {
  margin-left: auto;
  text-decoration: none;
}

.field {
  display: flex;
  flex-direction: column;
  font-size: 0.85rem;
  gap: 0.2rem;
}

.field select {
  font-size: 1.1rem;
  padding: 0.4rem 0.5rem;
  border-radius: 8px;
  border: 1px solid var(--border);
  min-height: 44px;
}

.btn {
  font-size: 1.05rem;
  padding: 0.6rem 1rem;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: #fff;
  color: var(--ink);
  min-height: 44px;
  cursor: pointer;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.btn-primary {
  background: var(--accent);
  color: var(--accent-ink);
  border-color: var(--accent);
}

.btn-big {
  font-size: 1.2rem;
  padding: 0.75rem 1.4rem;
}

.error-banner {
  margin: 0.75rem 1rem;
  padding: 0.75rem 1rem;
  background: var(--error-bg);
  color: var(--error-ink);
  border-radius: 8px;
  font-size: 1rem;
}

main {
  padding: 0.5rem 1rem 1rem 1rem;
}

.score-meta {
  font-size: 1.1rem;
  font-weight: 600;
  margin: 0.5rem 0;
  color: #333;
}

.paper {
  background: #fff;
  border-radius: 12px;
  border: 1px solid var(--border);
  padding: 0.5rem;
  width: 100%;
  overflow: hidden;
}

.paper svg {
  max-width: 100%;
  height: auto;
}

.abcjs-highlight {
  fill: var(--highlight) !important;
}

.gen-field input, .gen-field select {
  font-size: 0.95rem;
  padding: 0.35rem 0.4rem;
  border-radius: 8px;
  border: 1px solid var(--border);
  min-height: 40px;
  max-width: 9.5rem;
}

.generate-panel {
  margin: 0.75rem 1rem;
  padding: 0.9rem 1rem;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 10px;
}

.generate-title {
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.generate-attempts {
  list-style: none;
  margin: 0 0 0.5rem 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}

.generate-attempts li {
  font-size: 0.95rem;
  cursor: pointer;
}

.generate-attempts li .attempt-detail {
  display: none;
  font-size: 0.85rem;
  color: #555;
  margin-top: 0.15rem;
  white-space: pre-wrap;
}

.generate-attempts li.expanded .attempt-detail {
  display: block;
}

.generate-actions {
  display: flex;
  gap: 0.5rem;
}

/* H3：分手練習（右手／左手／雙手） */
.hands-practice {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  margin: 0.3rem 0 0.6rem 0;
  font-size: 0.95rem;
}

.hands-buttons {
  display: flex;
  gap: 0.4rem;
}

.hands-btn {
  padding: 0.4rem 0.8rem;
  min-height: 40px;
}

.hands-btn.active {
  background: var(--accent);
  color: var(--accent-ink);
  border-color: var(--accent);
}

/* 分手練習：淡化沒有在練的那一手（abcjs add_classes:true 會加上
   abcjs-v0（右手，V:RH 先宣告）／abcjs-v1（左手）class）。*/
.paper.dim-lh .abcjs-v1 {
  opacity: 0.3;
}

.paper.dim-rh .abcjs-v0 {
  opacity: 0.3;
}

/* two-hands K2：25 鍵鍵盤示意圖與八度按鈕 */
.keyboard-section {
  margin-top: 0.75rem;
}

.keyboard-row {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.keyboard {
  flex: 1;
  min-width: 220px;
  max-width: 480px;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 0.4rem;
}

.keyboard-svg {
  width: 100%;
  height: auto;
  display: block;
}

.key {
  stroke: #444;
  stroke-width: 0.5;
}

.key-white {
  fill: #ffffff;
}

.key-black {
  fill: #222222;
}

.key-rh {
  fill: #7ec4f2; /* 右手：藍 */
}

.key-lh {
  fill: #f2a65a; /* 左手：橘（H3 之後會用到） */
}

.key-active {
  fill: var(--highlight) !important;
}

.keyboard-c-label {
  font-size: 7px;
  fill: #777;
}

.octave-control {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.octave-value {
  font-size: 1.1rem;
  font-weight: 600;
  min-width: 2.2rem;
  text-align: center;
}

.keyboard-hint {
  margin: 0.5rem 0 0 0;
  font-size: 0.95rem;
  color: #555;
}

@media (max-width: 480px) {
  .keyboard-row {
    flex-direction: column;
    align-items: stretch;
  }
  .keyboard {
    max-width: none;
  }
  .octave-control {
    justify-content: center;
  }
}

.control-bar {
  position: sticky;
  bottom: 0;
  background: #fff;
  border-top: 1px solid var(--border);
  padding: 0.75rem 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.playback-row, .toggle-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem;
}

.tempo-field {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 1rem;
  flex: 1;
  min-width: 180px;
}

.tempo-field input[type="range"] {
  flex: 1;
  min-width: 100px;
  height: 32px;
}

.tempo-value {
  font-variant-numeric: tabular-nums;
  min-width: 5.5rem;
  text-align: right;
}

.check {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 1rem;
}

.check input {
  width: 22px;
  height: 22px;
}

@media (max-width: 480px) {
  body {
    font-size: 16px;
  }
  .playback-row, .toggle-row {
    flex-direction: row;
    justify-content: space-between;
  }
  .btn-big {
    font-size: 1.05rem;
    padding: 0.6rem 0.9rem;
  }
}

@media print {
  .topbar .selectors,
  .error-banner,
  .control-bar,
  .generate-panel,
  .keyboard-section,
  .hands-practice,
  #audio-widget {
    display: none !important;
  }
  body {
    background: #fff;
  }
  .paper {
    border: none;
  }
  /* P6 回饋 A.3：列印時不要殘留播放中的標亮顏色。 */
  .abcjs-highlight {
    fill: #000 !important;
  }
}