/**
 * Base Styles
 * CSS Variables, Reset, Typography, Utilities
 */

/* CSS Variables */
:root {
  /* Brand Colors */
  --color-brand: #F56902;
  --color-brand-dark: #D95A00;
  --color-brand-light: #FF8534;
  --color-brand-alpha: rgba(245, 105, 2, 0.1);
  
  /* Neutral Colors */
  --color-white: #FFFFFF;
  --color-black: #000000;
  --color-gray-50: #FAFAFA;
  --color-gray-100: #F5F5F5;
  --color-gray-200: #E5E5E5;
  --color-gray-300: #D4D4D4;
  --color-gray-400: #A3A3A3;
  --color-gray-500: #737373;
  --color-gray-600: #525252;
  --color-gray-700: #404040;
  --color-gray-800: #262626;
  --color-gray-900: #171717;
  
  /* Semantic Colors */
  --color-success: #22C55E;
  --color-warning: #EAB308;
  --color-error: #EF4444;
  --color-info: #3B82F6;
  
  /* Typography */
  --font-sans: 'DM Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-serif: 'DM Serif Display', Georgia, serif;
  
  /* Font Sizes */
  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 1.875rem;
  --text-4xl: 2.25rem;
  
  /* Line Heights */
  --leading-tight: 1.25;
  --leading-snug: 1.375;
  --leading-normal: 1.5;
  --leading-relaxed: 1.625;
  
  /* Spacing */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  
  /* Border Radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-2xl: 24px;
  --radius-full: 9999px;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;
  --transition-slow: 350ms ease;
  
  /* Z-index layers */
  --z-base: 1;
  --z-dropdown: 10;
  --z-sticky: 50;
  --z-fixed: 100;
  --z-modal: 200;
  --z-popover: 300;
  --z-tooltip: 400;
  
  /* Layout */
  --header-height: 64px;
  --sidebar-width: 260px;
  --player-height: 88px;
  --description-panel-width: 320px;
  --content-max-width: 1400px;
}

/* Reset */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-sans);
  font-size: var(--text-base);
  line-height: var(--leading-normal);
  color: var(--color-gray-900);
  background-color: var(--color-gray-50);
  min-height: 100vh;
  overflow-x: hidden;
}

img, picture, video, canvas, svg {
  display: block;
  max-width: 100%;
  height: auto;
}

button, input, select, textarea {
  font: inherit;
  color: inherit;
}

button {
  cursor: pointer;
  background: none;
  border: none;
}

a {
  color: inherit;
  text-decoration: none;
}

ul, ol {
  list-style: none;
}

h1, h2, h3, h4, h5, h6 {
  font-weight: 600;
  line-height: var(--leading-tight);
}

p {
  margin-bottom: var(--space-4);
}

p:last-child {
  margin-bottom: 0;
}

/* Scrollbar Styling */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

::-webkit-scrollbar-track {
  background: var(--color-gray-100);
}

::-webkit-scrollbar-thumb {
  background: var(--color-gray-300);
  border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--color-gray-400);
}

/* Selection */
::selection {
  background: var(--color-brand-alpha);
  color: var(--color-brand-dark);
}

/* Focus Styles */
:focus-visible {
  outline: 2px solid var(--color-brand);
  outline-offset: 2px;
}

/* Typography Utilities */
.text-xs { font-size: var(--text-xs); }
.text-sm { font-size: var(--text-sm); }
.text-base { font-size: var(--text-base); }
.text-lg { font-size: var(--text-lg); }
.text-xl { font-size: var(--text-xl); }
.text-2xl { font-size: var(--text-2xl); }
.text-3xl { font-size: var(--text-3xl); }

.font-normal { font-weight: 400; }
.font-medium { font-weight: 500; }
.font-semibold { font-weight: 600; }
.font-bold { font-weight: 700; }

.text-muted { color: var(--color-gray-500); }
.text-brand { color: var(--color-brand); }

/* Button Base */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-5);
  font-size: var(--text-sm);
  font-weight: 600;
  line-height: 1;
  border-radius: var(--radius-full);
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.btn svg {
  width: 18px;
  height: 18px;
}

.btn--primary {
  background: var(--color-brand);
  color: var(--color-white);
}

.btn--primary:hover {
  background: var(--color-brand-dark);
}

.btn--secondary {
  background: var(--color-gray-100);
  color: var(--color-gray-700);
}

.btn--secondary:hover {
  background: var(--color-gray-200);
}

.btn--text {
  background: transparent;
  color: var(--color-gray-600);
}

.btn--text:hover {
  color: var(--color-brand);
}

/* Loading Spinner */
.loading {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--space-16);
  gap: var(--space-4);
  color: var(--color-gray-500);
}

.loading__spinner {
  width: 40px;
  height: 40px;
  border: 3px solid var(--color-gray-200);
  border-top-color: var(--color-brand);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

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

/* Error State */
.error-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--space-16);
  gap: var(--space-4);
  text-align: center;
}

.error-state svg {
  width: 48px;
  height: 48px;
  color: var(--color-error);
}

.error-state p {
  color: var(--color-gray-600);
  max-width: 400px;
}

/* Empty Message */
.empty-message {
  text-align: center;
  padding: var(--space-12);
  color: var(--color-gray-500);
}

/* Coming Soon */
.coming-soon {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--space-16);
  gap: var(--space-6);
  text-align: center;
}

.coming-soon__icon {
  width: 80px;
  height: 80px;
  padding: var(--space-4);
  background: var(--color-brand-alpha);
  border-radius: var(--radius-full);
  color: var(--color-brand);
}

.coming-soon__icon svg {
  width: 100%;
  height: 100%;
}

.coming-soon__title {
  font-family: var(--font-serif);
  font-size: var(--text-3xl);
  color: var(--color-gray-900);
}

.coming-soon__text {
  color: var(--color-gray-500);
  max-width: 400px;
  line-height: var(--leading-relaxed);
}

/* Visually Hidden */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}