:root {
  /* Color Palette */
  --bg-dark: #0f111a;
  --bg-panel: rgba(25, 28, 41, 0.65);
  --bg-panel-hover: rgba(35, 39, 56, 0.8);
  --text-main: #f8f9fa;
  --text-muted: #8b92a5;
  --accent-primary: #e0263c;
  --accent-hover: #ff334b;
  --accent-glow: rgba(224, 38, 60, 0.4);
  --border-color: rgba(255, 255, 255, 0.08);
  --border-focus: rgba(224, 38, 60, 0.5);
  --success: #10b981;
  --error: #ef4444;

  /* Typography */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  
  /* Shadows & Glassmorphism */
  --shadow-sm: 0 4px 6px -1px rgba(0, 0, 0, 0.2), 0 2px 4px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 25px -5px rgba(0, 0, 0, 0.4), 0 8px 10px -6px rgba(0, 0, 0, 0.2);
  --shadow-glow: 0 0 20px var(--accent-glow);
  --backdrop-blur: blur(12px);

  /* Transitions */
  --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
  background-color: var(--bg-dark);
  color: var(--text-main);
  font-family: var(--font-family);
  min-height: 100vh;
  /* Premium dark background pattern */
  background-image: 
    radial-gradient(circle at 15% 50%, rgba(224, 38, 60, 0.08), transparent 25%),
    radial-gradient(circle at 85% 30%, rgba(67, 56, 202, 0.08), transparent 25%);
  background-attachment: fixed;
  display: flex;
  flex-direction: column;
  padding: 2rem 1rem;
}

/* Typography */
h1 {
  font-size: 2.5rem;
  font-weight: 800;
  letter-spacing: -0.025em;
  background: linear-gradient(135deg, #fff 0%, #a5a5a5 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: 0.5rem;
  text-align: center;
}

.subtitle {
  color: var(--text-muted);
  text-align: center;
  font-size: 1.1rem;
  margin-bottom: 3rem;
  font-weight: 400;
}

/* Layout */
.container {
  max-width: 1200px;
  margin: 0 auto;
  width: 100%;
}

.main-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
  align-items: start;
}

@media (min-width: 992px) {
  .main-grid {
    grid-template-columns: 400px 1fr;
  }
}

/* Glassmorphic Panels */
.panel {
  background: var(--bg-panel);
  backdrop-filter: var(--backdrop-blur);
  -webkit-backdrop-filter: var(--backdrop-blur);
  border: 1px solid var(--border-color);
  border-radius: 20px;
  padding: 2rem;
  box-shadow: var(--shadow-lg);
  transition: transform var(--transition-normal), background var(--transition-normal);
}

.panel:hover {
  background: var(--bg-panel-hover);
}

/* Form Elements */
.form-group {
  margin-bottom: 1.5rem;
}

label {
  display: block;
  font-size: 0.875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  margin-bottom: 0.75rem;
}

/* Segmented Control */
.segmented-control {
  display: flex;
  background: rgba(0, 0, 0, 0.3);
  border-radius: 12px;
  padding: 0.375rem;
  border: 1px solid var(--border-color);
}

.segmented-control button {
  flex: 1;
  background: transparent;
  border: none;
  color: var(--text-muted);
  padding: 0.75rem 1rem;
  font-size: 0.9rem;
  font-weight: 600;
  border-radius: 8px;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.segmented-control button:hover:not(.active) {
  color: var(--text-main);
  background: rgba(255, 255, 255, 0.05);
}

.segmented-control button.active {
  background: var(--accent-primary);
  color: white;
  box-shadow: var(--shadow-sm);
}

/* File Input Wrapper */
.file-upload-wrapper {
  position: relative;
  width: 100%;
  height: 120px;
  border: 2px dashed var(--border-color);
  border-radius: 12px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
  cursor: pointer;
  background: rgba(0, 0, 0, 0.2);
}

.file-upload-wrapper:hover, .file-upload-wrapper.dragover {
  border-color: var(--accent-primary);
  background: rgba(224, 38, 60, 0.05);
}

.file-upload-wrapper input[type="file"] {
  position: absolute;
  width: 100%;
  height: 100%;
  opacity: 0;
  cursor: pointer;
}

.file-upload-icon {
  font-size: 2rem;
  margin-bottom: 0.5rem;
  color: var(--text-muted);
  transition: color var(--transition-fast);
}

.file-upload-wrapper:hover .file-upload-icon {
  color: var(--accent-primary);
}

.file-upload-text {
  font-size: 0.9rem;
  color: var(--text-muted);
  text-align: center;
}

.file-name-display {
  display: none;
  font-size: 0.85rem;
  color: var(--accent-primary);
  margin-top: 0.5rem;
  word-break: break-all;
  text-align: center;
  padding: 0 1rem;
}

/* Textarea */
textarea {
  width: 100%;
  min-height: 100px;
  background: rgba(0, 0, 0, 0.3);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  color: var(--text-main);
  padding: 1rem;
  font-size: 1rem;
  font-family: var(--font-family);
  resize: vertical;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

textarea:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px rgba(224, 38, 60, 0.15);
}

/* Primary Button */
.btn-primary {
  width: 100%;
  padding: 1rem;
  border: none;
  border-radius: 12px;
  background: linear-gradient(135deg, var(--accent-primary) 0%, #b81d31 100%);
  color: white;
  font-size: 1rem;
  font-weight: 700;
  cursor: pointer;
  transition: all var(--transition-fast);
  box-shadow: var(--shadow-glow);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  margin-top: 1rem;
}

.btn-primary:hover:not(:disabled) {
  transform: translateY(-2px);
  box-shadow: 0 0 25px rgba(224, 38, 60, 0.6);
  background: linear-gradient(135deg, var(--accent-hover) 0%, var(--accent-primary) 100%);
}

.btn-primary:active:not(:disabled) {
  transform: translateY(0);
}

.btn-primary:disabled {
  background: #374151;
  color: #9ca3af;
  box-shadow: none;
  cursor: not-allowed;
  opacity: 0.7;
}

/* Secondary Controls (Play/Mute) */
.controls-row {
  display: flex;
  gap: 1rem;
  justify-content: center;
  margin-top: 1.5rem;
}

.btn-secondary {
  padding: 0.75rem 1.5rem;
  border-radius: 10px;
  border: 1px solid var(--border-color);
  background: rgba(0, 0, 0, 0.3);
  color: var(--text-main);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-fast);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.btn-secondary:hover:not(:disabled) {
  background: rgba(255, 255, 255, 0.1);
  border-color: rgba(255, 255, 255, 0.3);
}

.btn-secondary.active {
  background: rgba(224, 38, 60, 0.15);
  border-color: var(--border-focus);
  color: var(--accent-primary);
}

.btn-secondary:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

/* Stage / Preview Area */
.stage-wrapper {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 400px;
  position: relative;
  overflow: hidden;
}

.canvas-container {
  position: relative;
  width: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
  background: #000;
  border-radius: 12px;
  overflow: hidden;
  box-shadow: inset 0 0 20px rgba(0,0,0,0.5);
  border: 1px solid var(--border-color);
}

canvas {
  max-width: 100%;
  max-height: 70vh;
  object-fit: contain;
  display: block;
}

.preview-hint {
  margin-top: 1rem;
  font-size: 0.85rem;
  color: var(--text-muted);
  text-align: center;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
}

/* Status Banner */
.status-banner {
  margin-top: 1rem;
  padding: 1rem;
  border-radius: 12px;
  font-size: 0.9rem;
  font-weight: 500;
  text-align: center;
  display: none;
  animation: fadeIn 0.3s ease-out;
}

.status-banner.info {
  display: block;
  background: rgba(59, 130, 246, 0.1);
  border: 1px solid rgba(59, 130, 246, 0.3);
  color: #60a5fa;
}

.status-banner.success {
  display: block;
  background: rgba(16, 185, 129, 0.1);
  border: 1px solid rgba(16, 185, 129, 0.3);
  color: #34d399;
}

.status-banner.error {
  display: block;
  background: rgba(239, 68, 68, 0.1);
  border: 1px solid rgba(239, 68, 68, 0.3);
  color: #f87171;
}

.status-banner.loading {
  display: block;
  background: rgba(245, 158, 11, 0.1);
  border: 1px solid rgba(245, 158, 11, 0.3);
  color: #fbbf24;
}

/* Loader */
.spinner {
  display: inline-block;
  width: 20px;
  height: 20px;
  border: 3px solid rgba(255,255,255,0.3);
  border-radius: 50%;
  border-top-color: #fff;
  animation: spin 1s ease-in-out infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

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

/* Progress Bar */
.progress-container {
  width: 100%;
  height: 8px;
  background: rgba(0, 0, 0, 0.3);
  border-radius: 4px;
  margin-top: 0.5rem;
  overflow: hidden;
  display: none;
}

.progress-container.active {
  display: block;
}

.progress-bar {
  height: 100%;
  width: 0%;
  background: var(--accent-primary);
  border-radius: 4px;
  transition: width 0.3s ease;
  box-shadow: 0 0 10px var(--accent-glow);
}