app/src/index.css

:root {
  --bg: #07070e;
  --surface: #0f0f1a;
  --surface-2: #161628;
  --surface-3: #1c1c36;
  --border: #1e1e3a;
  --border-hover: #2e2e52;
  --primary: #8b5cf6;
  --primary-hover: #a78bfa;
  --primary-dim: #7c3aed;
  --primary-glow: rgba(139, 92, 246, 0.25);
  --accent: #06b6d4;
  --text: #f1f5f9;
  --text-muted: #94a3b8;
  --text-subtle: #525280;
  --danger: #ef4444;
  --danger-bg: rgba(239, 68, 68, 0.1);
  --radius: 10px;
  --radius-lg: 14px;
}

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

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  overflow: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

#root {
  width: 100vw;
  height: 100vh;
}

.app {
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
}

/* ========================================
   Upload Screen
   ======================================== */

.upload-screen {
  width: 100vw;
  height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg);
  background-image:
    radial-gradient(ellipse at 50% 30%, rgba(139, 92, 246, 0.08) 0%, transparent 60%),
    radial-gradient(ellipse at 50% 60%, rgba(6, 182, 212, 0.04) 0%, transparent 50%);
}

.upload-content {
  width: 100%;
  max-width: 520px;
  padding: 0 24px;
}

.upload-logo {
  display: flex;
  flex-direction: column;
  align-items: center;
  margin-bottom: 48px;
}

.upload-logo h1 {
  font-size: 36px;
  font-weight: 700;
  letter-spacing: -1px;
  background: linear-gradient(135deg, #a78bfa 0%, #06b6d4 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-top: 14px;
}

.upload-tagline {
  color: var(--text-muted);
  font-size: 16px;
  margin-top: 8px;
}

.upload-mode-tabs {
  display: flex;
  gap: 4px;
  margin-bottom: 20px;
  background: var(--surface-2);
  border-radius: var(--radius);
  padding: 4px;
  border: 1px solid var(--border);
}

.upload-mode-tab {
  flex: 1;
  padding: 10px 20px;
  border: none;
  border-radius: 7px;
  background: transparent;
  color: var(--text-muted);
  font-size: 14px;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  transition: all 0.15s;
}

.upload-mode-tab:hover {
  color: var(--text);
}

.upload-mode-tab.active {
  background: var(--primary);
  color: white;
  box-shadow: 0 2px 8px var(--primary-glow);
}

.upload-description {
  color: var(--text-muted);
  font-size: 14px;
  line-height: 1.6;
  text-align: center;
  margin-bottom: 28px;
}

/* Copyright notice */
.copyright-notice {
  margin-top: 20px;
  padding: 12px 16px;
  font-size: 12px;
  line-height: 1.5;
  color: var(--text-subtle);
  text-align: center;
  border-top: 1px solid var(--border);
}

/* Drop zone */
.drop-zone {
  border: 2px dashed var(--border);
  border-radius: var(--radius-lg);
  padding: 36px 24px;
  cursor: pointer;
  transition: all 0.2s;
  text-align: center;
}

.drop-zone:hover,
.drop-zone.dragging {
  border-color: var(--primary);
  background: rgba(139, 92, 246, 0.05);
  box-shadow: inset 0 0 30px rgba(139, 92, 246, 0.03);
}

.drop-icon {
  font-size: 32px;
  margin-bottom: 10px;
  opacity: 0.4;
}

.drop-zone p {
  color: var(--text-muted);
  font-size: 14px;
  font-weight: 500;
}

.drop-hint {
  font-size: 12px !important;
  color: var(--text-subtle) !important;
  font-weight: 400 !important;
  margin-top: 6px;
}

/* Error message */
.upload-error {
  margin-top: 20px;
  color: var(--danger);
  font-size: 13px;
  font-weight: 500;
  background: var(--danger-bg);
  padding: 12px 16px;
  border-radius: var(--radius);
  border: 1px solid rgba(239, 68, 68, 0.2);
}

/* ========================================
   Processing / Loading Screen
   ======================================== */

.upload-processing {
  text-align: center;
}

.processing-logo {
  animation: pulse 2s ease-in-out infinite;
  margin-bottom: 24px;
}

.upload-processing h2 {
  font-size: 24px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 8px;
}

.upload-processing p {
  color: var(--text-muted);
  font-size: 15px;
}

.loading-sub {
  margin-bottom: 28px;
}

.loading-bar {
  width: 200px;
  height: 4px;
  background: var(--border);
  border-radius: 2px;
  margin: 0 auto;
  overflow: hidden;
}

.loading-bar-fill {
  width: 40%;
  height: 100%;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  border-radius: 2px;
  animation: loading-slide 1.5s ease-in-out infinite;
}

@keyframes loading-slide {
  0% { transform: translateX(-100%); }
  100% { transform: translateX(350%); }
}

@keyframes pulse {
  0%, 100% { transform: scale(1); opacity: 1; }
  50% { transform: scale(1.08); opacity: 0.7; }
}

/* ========================================
   Controls Bar (Player)
   ======================================== */

.controls {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
  display: flex;
  flex-direction: column;
}

.controls-main {
  height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 24px;
  gap: 20px;
}

.controls-left {
  display: flex;
  align-items: center;
  gap: 16px;
  min-width: 0;
  flex: 1;
}

.brand-mark {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}

.brand-name {
  font-size: 16px;
  font-weight: 700;
  background: linear-gradient(135deg, #a78bfa, #06b6d4);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  white-space: nowrap;
  letter-spacing: -0.3px;
}

.file-name {
  font-size: 14px;
  color: var(--text-muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 240px;
  padding-left: 16px;
  border-left: 1.5px solid var(--border);
  font-weight: 500;
}

.controls-center {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}

.controls-right {
  display: flex;
  align-items: center;
  gap: 20px;
  flex: 1;
  justify-content: flex-end;
}

/* Transport buttons (skip back/forward) */
.transport-btn {
  width: 48px;
  height: 48px;
  border-radius: 10px;
  border: none;
  background: var(--surface-2);
  color: var(--text-muted);
  cursor: pointer;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 2px;
  transition: all 0.15s;
  border: 1px solid var(--border);
}

.transport-btn:hover {
  background: var(--surface-3);
  color: var(--text);
  border-color: var(--border-hover);
}

.transport-label {
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.3px;
  opacity: 0.7;
}

/* Play button — bold and prominent */
.play-btn {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  border: none;
  background: var(--primary);
  color: white;
  font-size: 20px;
  cursor: pointer;
  transition: all 0.2s;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 0 24px var(--primary-glow);
}

.play-btn:hover {
  background: var(--primary-hover);
  box-shadow: 0 0 36px var(--primary-glow);
  transform: scale(1.06);
}

.play-btn:active {
  transform: scale(0.96);
}

/* General button */
.btn {
  background: var(--surface-2);
  color: var(--text-muted);
  border: 1.5px solid var(--border);
  border-radius: 8px;
  padding: 8px 18px;
  font-size: 13px;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  transition: all 0.15s;
  white-space: nowrap;
  letter-spacing: 0.2px;
}

.btn:hover {
  background: var(--surface-3);
  color: var(--text);
  border-color: var(--border-hover);
}

.btn-new {
  border-color: var(--primary-dim);
  color: var(--primary-hover);
}

.btn-new:hover {
  background: rgba(139, 92, 246, 0.1);
  border-color: var(--primary);
  color: var(--primary-hover);
}

/* Tempo control */
.original-audio-control {
  display: flex;
  align-items: center;
  gap: 6px;
}

.btn-original {
  display: flex;
  align-items: center;
  gap: 5px;
  padding: 6px 12px;
  font-size: 12px;
  font-weight: 600;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--surface-2);
  color: var(--text-muted);
  cursor: pointer;
  white-space: nowrap;
  transition: all 0.15s ease;
}

.btn-original:hover {
  border-color: var(--primary);
  color: var(--text);
}

.btn-original.active {
  background: rgba(139, 92, 246, 0.15);
  border-color: var(--primary);
  color: var(--primary);
}

.original-volume {
  width: 60px;
}

.tempo-control {
  display: flex;
  align-items: center;
  gap: 10px;
  background: var(--surface-2);
  padding: 8px 16px;
  border-radius: 10px;
  border: 1px solid var(--border);
}

.tempo-label {
  font-size: 12px;
  font-weight: 700;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  white-space: nowrap;
}

.tempo-value {
  font-size: 14px;
  font-weight: 700;
  color: var(--text);
  min-width: 40px;
  text-align: right;
  font-variant-numeric: tabular-nums;
}

.tempo-control input[type='range'] {
  width: 100px;
}

/* ========================================
   Timeline / Progress Bar
   ======================================== */

.timeline {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 0 24px 12px;
}

.timeline-time {
  font-size: 13px;
  font-weight: 600;
  color: var(--text-muted);
  font-variant-numeric: tabular-nums;
  min-width: 40px;
}

.timeline-time:last-child {
  text-align: right;
}

.timeline-track {
  flex: 1;
  position: relative;
}

.timeline-track input[type='range'] {
  width: 100%;
  height: 8px;
  border-radius: 4px;
  -webkit-appearance: none;
  appearance: none;
  outline: none;
  cursor: pointer;
  transition: height 0.15s;
}

.timeline-track input[type='range']:hover {
  height: 10px;
}

.timeline-track input[type='range']::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--primary-hover);
  cursor: pointer;
  border: 2px solid white;
  box-shadow: 0 0 10px var(--primary-glow);
  transition: transform 0.1s;
}

.timeline-track input[type='range']::-webkit-slider-thumb:hover {
  transform: scale(1.25);
}

.timeline-track input[type='range']::-moz-range-thumb {
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--primary-hover);
  cursor: pointer;
  border: 2px solid white;
  box-shadow: 0 0 10px var(--primary-glow);
}

/* General range sliders (for tempo) */
input[type='range'] {
  -webkit-appearance: none;
  appearance: none;
  background: var(--border);
  height: 5px;
  border-radius: 3px;
  outline: none;
  cursor: pointer;
}

input[type='range']::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--primary);
  cursor: pointer;
  border: none;
  transition: transform 0.1s;
}

input[type='range']::-webkit-slider-thumb:hover {
  transform: scale(1.2);
}

input[type='range']::-moz-range-thumb {
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--primary);
  cursor: pointer;
  border: none;
}

/* Loop controls */
.loop-controls {
  display: flex;
  align-items: center;
  gap: 6px;
}

.loop-badge {
  font-size: 12px;
  font-weight: 600;
  color: var(--primary-hover);
  background: rgba(139, 92, 246, 0.12);
  padding: 5px 10px;
  border-radius: 6px;
  white-space: nowrap;
}

.loop-step {
  font-size: 12px;
  font-weight: 600;
  color: var(--text);
  white-space: nowrap;
}

.loop-arrow {
  font-size: 13px;
  color: var(--text-muted);
}

.btn-loop-action {
  font-size: 12px;
  font-weight: 600;
  padding: 5px 12px;
  border-radius: 6px;
  background: rgba(139, 92, 246, 0.1);
  border: 1px solid rgba(139, 92, 246, 0.25);
  color: var(--primary-hover);
  cursor: pointer;
  font-family: inherit;
  white-space: nowrap;
  transition: background 0.15s, border-color 0.15s;
}

.btn-loop-action:hover {
  background: rgba(139, 92, 246, 0.2);
  border-color: var(--primary);
}

.btn-loop-clear {
  font-size: 16px;
  line-height: 1;
  padding: 2px 6px;
  border-radius: 4px;
  background: transparent;
  border: 1px solid transparent;
  color: var(--text-muted);
  cursor: pointer;
  font-family: inherit;
  transition: color 0.15s, background 0.15s;
}

.btn-loop-clear:hover {
  color: var(--text);
  background: var(--surface-2);
}

/* ========================================
   View Tabs (Piano Roll / Sheet Music)
   ======================================== */

.view-tabs {
  display: flex;
  gap: 2px;
  padding: 8px 24px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}

.view-tab {
  padding: 8px 20px;
  border: 1.5px solid var(--border);
  border-radius: 8px;
  background: var(--surface-2);
  color: var(--text-muted);
  font-size: 13px;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  transition: all 0.15s;
  letter-spacing: 0.2px;
}

.view-tab:hover {
  background: var(--surface-3);
  color: var(--text);
  border-color: var(--border-hover);
}

.view-tab.active {
  background: rgba(139, 92, 246, 0.15);
  border-color: var(--primary);
  color: var(--primary-hover);
}

/* Canvas area */
.canvas-container {
  flex: 1;
  position: relative;
  overflow: hidden;
  width: 100%;
}

/* ========================================
   Sheet Music
   ======================================== */

.sheet-music-wrapper {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.sheet-music-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 24px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}

.sheet-music-info {
  font-size: 13px;
  color: var(--text-muted);
  font-weight: 500;
}

.btn-download {
  display: flex;
  align-items: center;
  gap: 8px;
  background: var(--surface-2);
  color: var(--text-muted);
  border: 1.5px solid var(--border);
  border-radius: 8px;
  padding: 8px 16px;
  font-size: 13px;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  transition: all 0.15s;
}

.btn-download:hover {
  background: var(--surface-3);
  color: var(--text);
  border-color: var(--border-hover);
}

.sheet-music-scroll {
  flex: 1;
  overflow: auto;
  background: #ffffff;
  position: relative;
}

.sheet-music-container {
  min-height: 100%;
  padding: 20px;
}

.sheet-music-container svg {
  display: block;
}

.sheet-music-progress-line {
  position: absolute;
  width: 2px;
  background: #8b5cf6;
  border-radius: 1px;
  pointer-events: none;
  display: none;
  z-index: 10;
  box-shadow: 0 0 6px rgba(139, 92, 246, 0.5);
}

.sheet-music-progress-line.smooth {
  transition: left 0.12s linear, top 0.12s linear;
}

.sheet-music-empty,
.tab-empty {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  font-size: 15px;
}

@media print {
  .controls, .view-tabs, .sheet-music-toolbar {
    display: none !important;
  }
  .sheet-music-scroll {
    overflow: visible;
  }
}