/* ============================================
   Spectrum Analyser — Light/Dark Theme
   ============================================ */

/* ── Light theme (default) ──────────────────── */
:root,
[data-theme="light"] {
  --bg-primary: #f4f5f8;
  --bg-secondary: #ffffff;
  --bg-tertiary: #ebedf2;
  --bg-elevated: #f0f1f5;
  --bg-hover: #e2e4ea;

  --text-primary: #1a1a2e;
  --text-secondary: #555570;
  --text-muted: #8888a0;

  --accent-primary: #6c4ce6;
  --accent-secondary: #4a7cf6;
  --accent-glow: rgba(108, 76, 230, 0.18);
  --accent-gradient: linear-gradient(135deg, #6c4ce6, #4a7cf6);

  --border-color: rgba(0, 0, 0, 0.08);
  --border-active: rgba(108, 76, 230, 0.4);

  --success: #22a85a;

  --canvas-bg: #0d0d14;
  --axis-text: #666680;
  --axis-grid: rgba(255, 255, 255, 0.4);
  --axis-border: rgba(255, 255, 255, 0.3);

  --shadow-sm: 0 1px 4px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 2px 12px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 4px 24px rgba(0, 0, 0, 0.10);
  --shadow-glow: 0 0 16px var(--accent-glow);
}

/* ── Dark theme ─────────────────────────────── */
[data-theme="dark"] {
  --bg-primary: #0a0a0f;
  --bg-secondary: #12121a;
  --bg-tertiary: #1a1a28;
  --bg-elevated: #1e1e2e;
  --bg-hover: #252538;

  --text-primary: #e8e8f0;
  --text-secondary: #9898b0;
  --text-muted: #5e5e78;

  --accent-primary: #7c5cfc;
  --accent-secondary: #5c8cfc;
  --accent-glow: rgba(124, 92, 252, 0.3);
  --accent-gradient: linear-gradient(135deg, #7c5cfc, #5c8cfc);

  --border-color: rgba(255, 255, 255, 0.06);
  --border-active: rgba(124, 92, 252, 0.4);

  --success: #4cdf8a;

  --canvas-bg: #050508;
  --axis-text: #5e5e78;
  --axis-grid: rgba(255, 255, 255, 0.5);
  --axis-border: rgba(255, 255, 255, 0.4);

  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 20px var(--accent-glow);
}

/* ── Shared tokens ──────────────────────────── */
:root {
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --font-sans: 'Inter', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-smooth: 400ms cubic-bezier(0.16, 1, 0.3, 1);
}

/* ============================================
   Reset & Base
   ============================================ */

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; -webkit-font-smoothing: antialiased; }

body {
  font-family: var(--font-sans);
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  overflow-x: hidden;
  transition: background var(--transition-base), color var(--transition-base);
}

[data-theme="dark"] body::before {
  content: '';
  position: fixed;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 50% at 50% -20%, rgba(124, 92, 252, 0.08), transparent),
    radial-gradient(ellipse 60% 40% at 80% 100%, rgba(92, 140, 252, 0.05), transparent);
  pointer-events: none;
}

/* ============================================
   Layout
   ============================================ */

.app {
  position: relative;
  z-index: 1;
  max-width: 1200px;
  margin: 0 auto;
  padding: 24px 24px 16px;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* ============================================
   Header
   ============================================ */

.header {
  text-align: center;
  padding: 48px 0 32px;
  position: relative;
}

.header-glow {
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 300px;
  height: 120px;
  background: radial-gradient(ellipse, var(--accent-glow), transparent 70%);
  filter: blur(40px);
  pointer-events: none;
}

.title {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.title-icon {
  display: none;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  background: var(--accent-gradient);
  -webkit-text-fill-color: initial;
  color: white;
  flex-shrink: 0;
  animation: pulse-glow 3s ease-in-out infinite;
}

@keyframes pulse-glow {
  0%, 100% { box-shadow: 0 0 15px var(--accent-glow); }
  50% { box-shadow: 0 0 30px var(--accent-glow), 0 0 60px rgba(124, 92, 252, 0.1); }
}

.subtitle {
  margin-top: 8px;
  color: var(--text-secondary);
  font-size: 0.95rem;
}

/* ── Theme Toggle ─────────────────────────── */
.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
  -webkit-text-fill-color: initial;
  margin-left: 8px;
  flex-shrink: 0;
}

.theme-toggle:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
  border-color: var(--accent-primary);
}

/* In light mode, show moon (switch to dark), hide sun */
[data-theme="light"] .icon-sun { display: none; }
[data-theme="light"] .icon-moon { display: block; }

/* In dark mode, show sun (switch to light), hide moon */
[data-theme="dark"] .icon-sun { display: block; }
[data-theme="dark"] .icon-moon { display: none; }

/* ============================================
   Controls Panel
   ============================================ */

.controls-panel {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 24px;
  margin-bottom: 24px;
  box-shadow: var(--shadow-md);
  transition: background var(--transition-base), border-color var(--transition-base);
}

.controls-row {
  display: flex;
  gap: 32px;
  align-items: flex-start;
  flex-wrap: wrap;
}

.control-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.control-group:first-child {
  flex: 1;
  min-width: 200px;
}

.control-label {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
}

.upload-btn {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px;
  background: var(--bg-tertiary);
  border: 1.5px dashed var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  font-family: var(--font-sans);
  font-size: 0.875rem;
  cursor: pointer;
  transition: all var(--transition-base);
  width: 100%;
}

.upload-btn:hover {
  border-color: var(--accent-primary);
  color: var(--text-primary);
  background: var(--bg-hover);
  box-shadow: var(--shadow-glow);
}

.upload-btn.has-file {
  border-style: solid;
  border-color: var(--success);
  color: var(--success);
}

.upload-zone.drag-over .upload-btn {
  border-color: var(--accent-primary);
  background: rgba(108, 76, 230, 0.08);
  color: var(--accent-primary);
}

.audio-input-row {
  display: flex;
  gap: 8px;
  align-items: stretch;
}

.upload-zone {
  flex: 1;
}

.demo-select-wrapper {
  position: relative;
  flex: 1;
}

.demo-select {
  width: 100%;
  height: 100%;
  padding: 8px 32px 8px 12px;
  background: var(--bg-tertiary);
  border: 1.5px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 0.875rem;
  cursor: pointer;
  appearance: none;
  -webkit-appearance: none;
  transition: all var(--transition-base);
}

.demo-select:hover {
  border-color: var(--accent-primary);
}

.demo-select:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: var(--shadow-glow);
}

.select-icon {
  position: absolute;
  right: 12px;
  top: 50%;
  transform: translateY(-50%);
  pointer-events: none;
  color: var(--text-secondary);
}

.scale-toggle {
  display: flex;
  position: relative;
  background: var(--bg-tertiary);
  border-radius: var(--radius-md);
  padding: 3px;
  border: 1px solid var(--border-color);
}

.toggle-option {
  position: relative;
  z-index: 1;
  cursor: pointer;
  display: flex;
  align-items: center;
}

.toggle-option input {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

.toggle-label {
  display: block;
  padding: 6px 16px;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--text-muted);
  border-radius: 7px;
  transition: color var(--transition-fast);
  white-space: nowrap;
}

.toggle-option input:checked + .toggle-label {
  color: var(--text-primary);
}

.toggle-indicator {
  position: absolute;
  top: 3px;
  left: 3px;
  height: calc(100% - 6px);
  width: calc(50% - 3px);
  background: var(--bg-elevated);
  border-radius: 7px;
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-smooth);
  pointer-events: none;
}

.toggle-indicator.log { transform: translateX(100%); }
.toggle-indicator.grid-off { transform: translateX(100%); }

/* Speed Toggle (10 options in 2x5 grid) */
.speed-control-group {
  /* Fix height to match a single-row toggle so the 2nd row overflows
     into the natural gap without pushing other controls down */
  height: 62px;       /* label (~16px) + gap (8px) + single toggle row (~38px) */
  overflow: visible;
}
.speed-toggle {
  display: flex !important;
  flex-direction: column !important;
}
.speed-row {
  display: flex !important;
  flex-direction: row !important;
  width: 100% !important;
}
.speed-row .toggle-option {
  flex: 1 !important;
  justify-content: center !important;
}
.speed-toggle .toggle-indicator {
  width: calc(20% - 1.2px) !important;
  height: 28px !important; /* Definite pixel height to fix WebKit dynamic height bug */
}
.toggle-indicator.speed-1 { transform: translate(0, 0); }
.toggle-indicator.speed-2 { transform: translate(100%, 0); }
.toggle-indicator.speed-3 { transform: translate(200%, 0); }
.toggle-indicator.speed-4 { transform: translate(300%, 0); }
.toggle-indicator.speed-5 { transform: translate(400%, 0); }
.toggle-indicator.speed-6 { transform: translate(0, 28px); }
.toggle-indicator.speed-7 { transform: translate(100%, 28px); }
.toggle-indicator.speed-8 { transform: translate(200%, 28px); }
.toggle-indicator.speed-9 { transform: translate(300%, 28px); }
.toggle-indicator.speed-10 { transform: translate(400%, 28px); }

.playback-controls {
  display: flex;
  align-items: center;
  gap: 8px;
}

.play-btn, .stop-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.play-btn:hover:not(:disabled), .stop-btn:hover:not(:disabled) {
  background: var(--bg-hover);
  color: var(--text-primary);
  border-color: var(--accent-primary);
}

.play-btn:disabled, .stop-btn:disabled {
  opacity: 0.35;
  cursor: not-allowed;
}

.play-btn.playing {
  background: var(--accent-primary);
  border-color: var(--accent-primary);
  color: white;
  box-shadow: var(--shadow-glow);
}

.clear-btn, .copy-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.clear-btn:hover, .copy-btn:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
  border-color: var(--accent-primary);
}

.time-display {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--text-muted);
  min-width: 90px;
}

.volume-control {
  display: flex;
  align-items: center;
  height: 40px;
}

.volume-slider {
  width: 100%;
  -webkit-appearance: none;
  appearance: none;
  background: var(--bg-tertiary);
  height: 6px;
  border-radius: 3px;
  outline: none;
  cursor: pointer;
}

.volume-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--accent-primary);
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-fast);
}

.volume-slider::-webkit-slider-thumb:hover {
  transform: scale(1.2);
}

.volume-slider::-moz-range-thumb {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--accent-primary);
  border: none;
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-fast);
}

.volume-slider::-moz-range-thumb:hover {
  transform: scale(1.2);
}

.hidden { display: none !important; }

.progress-container {
  margin-top: 16px;
  padding-top: 16px;
  border-top: 1px solid var(--border-color);
}

.progress-bar {
  position: relative;
  height: 6px;
  background: var(--bg-tertiary);
  border-radius: 3px;
}

.progress-fill {
  position: absolute;
  top: 0;
  left: 0;
  height: 100%;
  width: 0%;
  background: var(--accent-gradient);
  border-radius: 3px;
  transition: width 100ms linear;
}

.progress-input {
  position: absolute;
  top: -8px;
  left: 0;
  width: 100%;
  height: 22px;
  -webkit-appearance: none;
  appearance: none;
  background: transparent;
  cursor: pointer;
  z-index: 2;
}

.progress-input::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--accent-primary);
  box-shadow: 0 0 8px var(--accent-glow);
  border: 2px solid var(--bg-primary);
}

.progress-input::-moz-range-thumb {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--accent-primary);
  border: 2px solid var(--bg-primary);
}

/* ============================================
   Visualizer
   ============================================ */

.visualizer {
  flex: 1;
  min-height: 600px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
  position: relative;
  transition: background var(--transition-base), border-color var(--transition-base);
}

.viz-placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100%;
  min-height: 600px;
  gap: 16px;
  animation: fadeIn 0.6s ease;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

.viz-placeholder-icon {
  width: 100px;
  height: 100px;
  border-radius: 50%;
  background: var(--bg-tertiary);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  animation: float 4s ease-in-out infinite;
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-8px); }
}

.viz-placeholder-text {
  color: var(--text-secondary);
  font-size: 1rem;
  font-weight: 500;
}

.viz-placeholder-hint {
  color: var(--text-muted);
  font-size: 0.8125rem;
}

.canvas-wrapper {
  position: relative;
  width: 100%;
  height: 100%;
  min-height: 600px;
}

#spectrogram-canvas {
  position: absolute;
  top: 0;
  left: 60px;
  width: calc(100% - 60px);
  height: calc(100% - 36px);
}

#axis-canvas {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
}

/* Tooltip */
.hover-tooltip {
  position: absolute;
  background: var(--bg-elevated);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding: 4px 8px;
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  pointer-events: none;
  box-shadow: var(--shadow-sm);
  z-index: 10;
  transform: translate(10px, -50%);
  white-space: nowrap;
}

/* ============================================
   Footer
   ============================================ */

.footer {
  display: none;
  text-align: center;
  padding: 24px 0 8px;
  color: var(--text-muted);
  font-size: 0.75rem;
}

/* ============================================
   Stego Switch
   ============================================ */
.stego-switch-ui {
  position: relative;
  display: inline-block;
  width: 32px;
  height: 18px;
  flex-shrink: 0;
}
.stego-switch-ui input {
  opacity: 0;
  width: 0;
  height: 0;
}
.stego-slider {
  position: absolute;
  cursor: pointer;
  top: 0; left: 0; right: 0; bottom: 0;
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  transition: .3s;
  border-radius: 18px;
}
.stego-slider:before {
  position: absolute;
  content: "";
  height: 12px;
  width: 12px;
  left: 2px;
  bottom: 2px;
  background-color: var(--text-muted);
  transition: .3s;
  border-radius: 50%;
}
.stego-switch-ui input:checked + .stego-slider {
  background-color: var(--accent-primary);
  border-color: var(--accent-primary);
}
.stego-switch-ui input:checked + .stego-slider:before {
  transform: translateX(14px);
  background-color: #fff;
}

/* ============================================
   Responsive
   ============================================ */

@media (max-width: 768px) {
  .app { padding: 16px 16px 8px; }
  .header { padding: 32px 0 24px; }
  .title { font-size: 1.5rem; }
  .controls-row { flex-direction: column; gap: 16px; }
  .control-group:first-child { min-width: unset; }
  .visualizer { min-height: 450px; }
  .canvas-wrapper { min-height: 450px; }
}