:root {
  --bg: #f3efe4;
  --panel: rgba(255, 251, 244, 0.88);
  --line: rgba(38, 41, 57, 0.12);
  --text: #202331;
  --muted: #63697b;
  --accent: #1d8c9f;
  --accent-soft: rgba(29, 140, 159, 0.14);
  --accent-2: #d86154;
  --accent-2-soft: rgba(216, 97, 84, 0.16);
  --gold: #f3b84c;
  --shadow: 0 20px 50px rgba(38, 41, 57, 0.12);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at top left, rgba(29, 140, 159, 0.18), transparent 28%),
    radial-gradient(circle at top right, rgba(243, 184, 76, 0.24), transparent 22%),
    linear-gradient(180deg, #fff8ed 0%, var(--bg) 55%, #ebe5d9 100%);
  min-height: 100vh;
  -webkit-tap-highlight-color: transparent;
  touch-action: manipulation;
}

.app-shell {
  width: min(1400px, calc(100vw - 28px));
  margin: 0 auto;
  padding: 24px 0 42px;
}

.tablet-banner {
  display: flex;
  justify-content: space-between;
  gap: 14px;
  align-items: center;
  padding: 12px 16px;
  margin-bottom: 14px;
  border-radius: 18px;
  background: linear-gradient(135deg, rgba(29, 140, 159, 0.16), rgba(243, 184, 76, 0.2));
  border: 1px solid rgba(29, 140, 159, 0.16);
  color: var(--text);
  font-size: 14px;
  line-height: 1.5;
}

.tablet-banner strong {
  white-space: nowrap;
}

.install-panel {
  padding: 18px 20px;
  margin-bottom: 18px;
  border-radius: 22px;
  background: linear-gradient(145deg, rgba(255, 255, 255, 0.78), rgba(29, 140, 159, 0.08));
  border: 1px solid rgba(29, 140, 159, 0.12);
  box-shadow: var(--shadow);
}

.install-title-row {
  margin-bottom: 12px;
}

.install-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
}

.install-step-card {
  padding: 14px;
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.7);
  border: 1px solid rgba(38, 41, 57, 0.08);
}

.install-step-card strong {
  display: block;
  margin-bottom: 8px;
}

.install-step-card p,
.install-note {
  margin: 0;
  color: var(--muted);
  line-height: 1.6;
}

.install-note {
  margin-top: 12px;
}

.hero {
  display: grid;
  grid-template-columns: 1.5fr 0.9fr;
  gap: 18px;
  align-items: stretch;
  margin-bottom: 18px;
}

.big-action-panel {
  padding: 18px 20px;
  margin-bottom: 18px;
}

.big-action-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
}

.big-action-btn {
  min-height: 68px;
  font-size: 18px;
  font-weight: 700;
  border-radius: 18px;
}

.compact-button-row {
  grid-template-columns: 1fr;
}

.hero,
.panel {
  background: var(--panel);
  border: 1px solid rgba(255, 255, 255, 0.55);
  box-shadow: var(--shadow);
  border-radius: 26px;
  backdrop-filter: blur(18px);
}

.hero {
  padding: 26px 28px;
}

.eyebrow {
  margin: 0 0 10px;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.18em;
  font-size: 12px;
  font-weight: 700;
}

h1 {
  margin: 0;
  font-size: clamp(28px, 4vw, 48px);
  line-height: 1.05;
}

.hero-copy {
  margin: 16px 0 0;
  max-width: 64ch;
  color: var(--muted);
  line-height: 1.65;
}

.hero-card {
  display: grid;
  gap: 12px;
  background: linear-gradient(160deg, rgba(29, 140, 159, 0.12), rgba(243, 184, 76, 0.15));
  border-radius: 20px;
  padding: 18px;
}

.metric {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 16px;
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.52);
}

.metric-label {
  color: var(--muted);
  font-size: 14px;
}

.metric-value {
  font-weight: 700;
}

.layout {
  display: grid;
  grid-template-columns: 380px 1fr;
  gap: 18px;
}

.panel {
  padding: 20px;
}

.controls-panel,
.steps-panel {
  grid-column: 1;
}

.visual-panel,
.hand-panel {
  grid-column: 2;
}

.hand-panel,
.steps-panel {
  display: none;
}

.panel-title-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
  margin-bottom: 16px;
}

h2, h3 {
  margin: 0;
}

.badge,
.subtle {
  color: var(--muted);
  font-size: 13px;
}

.badge {
  padding: 7px 10px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.72);
}

.upload-box {
  position: relative;
  border: 2px dashed rgba(29, 140, 159, 0.32);
  border-radius: 20px;
  padding: 22px;
  text-align: center;
  background: linear-gradient(180deg, rgba(29, 140, 159, 0.08), rgba(29, 140, 159, 0.02));
  margin-bottom: 18px;
}

.upload-box.dragging {
  border-color: var(--accent-2);
  background: linear-gradient(180deg, rgba(216, 97, 84, 0.11), rgba(216, 97, 84, 0.03));
}

.upload-box input {
  position: absolute;
  inset: 0;
  opacity: 0;
  cursor: pointer;
}

.upload-box p {
  margin: 0 0 8px;
  font-weight: 700;
}

.upload-box small {
  color: var(--muted);
}

.control-grid {
  display: grid;
  gap: 14px;
}

.control-grid label {
  display: grid;
  gap: 8px;
  padding: 14px 14px 12px;
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.6);
}

.control-grid span,
.control-grid strong {
  font-size: 14px;
}

input[type="range"],
select,
button {
  width: 100%;
}

select,
button {
  border: 1px solid var(--line);
  border-radius: 14px;
  font: inherit;
  padding: 13px 14px;
  background: #fffdf8;
  color: var(--text);
}

button {
  cursor: pointer;
  transition: transform 0.18s ease, box-shadow 0.18s ease;
}

button:hover {
  transform: translateY(-1px);
}

button.primary {
  background: linear-gradient(135deg, var(--accent), #14717f);
  color: white;
  border-color: transparent;
}

.button-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  margin: 18px 0;
}

.practice-card {
  margin-bottom: 18px;
  padding: 16px;
  border-radius: 18px;
  background: linear-gradient(180deg, rgba(29, 140, 159, 0.12), rgba(255, 255, 255, 0.7));
  border: 1px solid rgba(29, 140, 159, 0.14);
}

.practice-title-row {
  margin-bottom: 10px;
}

.practice-copy {
  margin: 0 0 14px;
  color: var(--muted);
  line-height: 1.6;
}

.practice-button-row {
  margin: 0 0 14px;
  grid-template-columns: 1fr;
}

.practice-status-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
}

.practice-status-item {
  display: grid;
  gap: 6px;
  padding: 12px;
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.74);
}

.practice-status-item span {
  font-size: 13px;
  color: var(--muted);
}

.practice-status-item strong {
  font-size: 15px;
}

.practice-meta {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  margin-top: 12px;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.5;
}

.practice-good {
  color: #1e8d57;
}

.practice-bad {
  color: #ba4638;
}

.practice-warn {
  color: #9a6a09;
}

.practice-debug-panel {
  margin-top: 14px;
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.62);
  border: 1px solid rgba(38, 41, 57, 0.08);
  overflow: hidden;
}

.practice-debug-panel summary {
  cursor: pointer;
  padding: 14px 16px;
  font-weight: 700;
  list-style: none;
}

.practice-debug-panel summary::-webkit-details-marker {
  display: none;
}

.practice-debug-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
  padding: 0 16px 16px;
}

.practice-debug-item {
  display: grid;
  gap: 6px;
  padding: 12px;
  border-radius: 14px;
  background: rgba(255, 253, 248, 0.86);
}

.practice-debug-item span {
  font-size: 12px;
  color: var(--muted);
}

.practice-debug-item strong {
  font-size: 14px;
  line-height: 1.45;
  word-break: break-word;
}

.practice-debug-wide {
  grid-column: 1 / -1;
}

.progress-wrap {
  padding: 14px;
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.6);
}

.progress-labels {
  display: flex;
  justify-content: space-between;
  color: var(--muted);
  font-size: 13px;
  margin-top: 8px;
}

.tips-card {
  margin-top: 16px;
  padding: 16px;
  border-radius: 18px;
  background: linear-gradient(180deg, rgba(243, 184, 76, 0.14), rgba(255, 255, 255, 0.55));
}

.tips-card p {
  margin: 10px 0 0;
  line-height: 1.65;
  color: var(--muted);
}

canvas {
  width: 100%;
  display: block;
  border-radius: 18px;
  background: linear-gradient(180deg, rgba(10, 18, 30, 0.95), rgba(18, 28, 42, 0.93));
}

.keyboard {
  display: flex;
  position: relative;
  height: 170px;
  border-radius: 18px;
  overflow: hidden;
  background: #11151f;
  box-shadow: inset 0 10px 25px rgba(0, 0, 0, 0.3);
}

.keyboard-stage {
  position: relative;
  margin-top: 14px;
}

.overlay-hand-canvas {
  position: absolute;
  left: 0;
  bottom: 0;
  height: 180px;
  pointer-events: none;
  background: transparent;
  z-index: 3;
}

.white-key {
  position: relative;
  flex: 1 1 0;
  background: linear-gradient(180deg, #ffffff 0%, #f0ece4 100%);
  border-right: 1px solid rgba(36, 36, 36, 0.1);
}

.white-key.active-right {
  background: linear-gradient(180deg, #c6f8ff 0%, #72d9e8 100%);
}

.white-key.active-left {
  background: linear-gradient(180deg, #ffd4c9 0%, #f08c77 100%);
}

.white-key.target-note {
  box-shadow: inset 0 0 0 3px rgba(243, 184, 76, 0.95);
}

.white-key.detected-note {
  box-shadow: inset 0 0 0 3px rgba(29, 141, 87, 0.9);
}

.white-key span {
  position: absolute;
  bottom: 10px;
  left: 50%;
  transform: translateX(-50%);
  font-size: 11px;
  color: rgba(32, 35, 49, 0.72);
}

.black-key {
  position: absolute;
  top: 0;
  width: calc(100% / 52 * 0.66);
  height: 60%;
  border-radius: 0 0 10px 10px;
  background: linear-gradient(180deg, #273142 0%, #11151f 100%);
  box-shadow: 0 8px 18px rgba(0, 0, 0, 0.45);
}

.black-key.active-right {
  background: linear-gradient(180deg, #5ce6ff 0%, #167d93 100%);
}

.black-key.active-left {
  background: linear-gradient(180deg, #ff9a88 0%, #b94a3b 100%);
}

.black-key.target-note {
  box-shadow: inset 0 0 0 2px rgba(243, 184, 76, 0.95);
}

.black-key.detected-note {
  box-shadow: inset 0 0 0 2px rgba(29, 141, 87, 0.9);
}

.legend {
  display: flex;
  gap: 18px;
  margin-top: 12px;
  color: var(--muted);
  font-size: 13px;
}

.dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  display: inline-block;
  margin-right: 6px;
}

.right-dot {
  background: var(--accent);
}

.left-dot {
  background: var(--accent-2);
}

.active-dot {
  background: var(--gold);
}

.steps-panel ol {
  padding-left: 20px;
  margin: 0;
  color: var(--muted);
  line-height: 1.75;
}

@media (max-width: 1100px) {
  .hero,
  .layout {
    grid-template-columns: 1fr;
  }

  .install-grid,
  .big-action-grid {
    grid-template-columns: 1fr;
  }

  .controls-panel,
  .steps-panel,
  .visual-panel,
  .hand-panel {
    grid-column: 1;
  }

  .controls-panel {
    order: 1;
  }

  .visual-panel {
    order: 2;
  }
}

@media (max-width: 700px) {
  .app-shell {
    width: min(100vw - 16px, 100%);
    padding-top: 10px;
  }

  .hero,
  .panel {
    border-radius: 20px;
  }

  .hero {
    padding: 18px;
  }

  .panel {
    padding: 16px;
  }

  .tablet-banner {
    flex-direction: column;
    align-items: flex-start;
    border-radius: 16px;
  }

  .button-row {
    grid-template-columns: 1fr;
  }

  .practice-status-grid {
    grid-template-columns: 1fr;
  }

  .practice-meta {
    flex-direction: column;
  }

  .keyboard {
    height: 126px;
  }
}

@media (max-width: 1024px) and (orientation: landscape) {
  .app-shell {
    width: min(100vw - 20px, 100%);
    padding-top: 14px;
  }

  .layout {
    grid-template-columns: 340px 1fr;
    gap: 14px;
  }

  .hero {
    grid-template-columns: 1.2fr 0.9fr;
    padding: 20px 22px;
  }

  .big-action-grid {
    grid-template-columns: repeat(3, 1fr);
  }

  .panel {
    padding: 16px;
  }

  .keyboard {
    height: 142px;
  }

  .overlay-hand-canvas {
    height: 154px;
  }
}