/* ============================================
   ARTISTIC MUSIC ANALYTICS DESIGN SYSTEM
   ============================================ */

/* Design Tokens - Color Palette */
:root {
  /* Background Colors */
  --bg-primary: #0a0a0a;
  --bg-secondary: #121212;
  --bg-tertiary: #1a1a1a;
  --bg-elevated: #1f1f1f;
  
  /* Primary Accent - Spotify Green */
  --accent-primary: #1DB954;
  --accent-primary-light: #1ed760;
  --accent-primary-dark: #1aa34a;
  
  /* Secondary Accents */
  --accent-blue: #00D4FF;
  --accent-magenta: #FF00E5;
  --accent-amber: #FFB800;
  --accent-purple: #8B5CF6;
  
  /* Text Colors */
  --text-primary: #FFFFFF;
  --text-secondary: rgba(255, 255, 255, 0.7);
  --text-tertiary: rgba(255, 255, 255, 0.5);
  --text-muted: rgba(255, 255, 255, 0.3);
  
  /* Data-reactive Colors */
  --data-high: #1DB954;
  --data-medium: #FFB800;
  --data-low: #FF00E5;
  
  /* Gradients */
  --gradient-primary: linear-gradient(135deg, #1DB954 0%, #00D4FF 100%);
  --gradient-secondary: linear-gradient(135deg, #FF00E5 0%, #8B5CF6 100%);
  --gradient-bg: linear-gradient(180deg, #0a0a0a 0%, #121212 50%, #1a1a1a 100%);
  --gradient-hero: radial-gradient(ellipse at center, rgba(29, 185, 84, 0.15) 0%, transparent 70%);
  
  /* Typography Scale */
  --font-family-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-weight-light: 300;
  --font-weight-regular: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  --font-weight-black: 900;
  
  /* Type Scale (1.25x ratio) */
  --text-xs: 0.75rem;      /* 12px */
  --text-sm: 0.875rem;      /* 14px */
  --text-base: 1rem;        /* 16px */
  --text-lg: 1.25rem;       /* 20px */
  --text-xl: 1.563rem;      /* 25px */
  --text-2xl: 1.953rem;     /* 31px */
  --text-3xl: 2.441rem;     /* 39px */
  --text-4xl: 3.052rem;     /* 49px */
  --text-5xl: 3.815rem;     /* 61px */
  --text-6xl: 4.768rem;     /* 76px */
  --text-7xl: 5.96rem;      /* 95px */
  --text-8xl: 7.451rem;     /* 119px */
  
  /* Spacing Scale */
  --space-xs: 0.5rem;
  --space-sm: 1rem;
  --space-md: 1.5rem;
  --space-lg: 2rem;
  --space-xl: 3rem;
  --space-2xl: 4rem;
  --space-3xl: 6rem;
  --space-4xl: 8rem;
  
  /* Border Radius */
  --radius-sm: 0.5rem;
  --radius-md: 1rem;
  --radius-lg: 1.5rem;
  --radius-xl: 2rem;
  --radius-full: 9999px;
  
  /* Shadows & Glows */
  --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);
  --glow-primary: 0 0 20px rgba(29, 185, 84, 0.4);
  --glow-blue: 0 0 20px rgba(0, 212, 255, 0.4);
  --glow-magenta: 0 0 20px rgba(255, 0, 229, 0.4);
  
  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 300ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 500ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-bounce: 600ms cubic-bezier(0.68, -0.55, 0.265, 1.55);
  
  /* Z-index Scale */
  --z-base: 1;
  --z-elevated: 10;
  --z-sticky: 100;
  --z-overlay: 1000;
  --z-modal: 2000;
}

/* ============================================
   BASE STYLES
   ============================================ */

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family-primary);
  font-size: var(--text-base);
  font-weight: var(--font-weight-regular);
  line-height: 1.6;
  color: var(--text-primary);
  background: var(--bg-primary);
  background-image: var(--gradient-bg);
  min-height: 100vh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  padding: 0;
  margin: 0;
}

main {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 var(--space-xl);
}

/* Grain/Noise Texture Overlay */
body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 400 400' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noiseFilter'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noiseFilter)' opacity='0.03'/%3E%3C/svg%3E");
  pointer-events: none;
  z-index: var(--z-base);
}

/* ============================================
   ABSTRACT GEOMETRIC SHAPES
   ============================================ */

.abstract-shape {
  position: absolute;
  border-radius: 50%;
  filter: blur(60px);
  opacity: 0.08;
  pointer-events: none;
  z-index: var(--z-base);
}

.shape-1 {
  width: 400px;
  height: 400px;
  background: var(--accent-primary);
  top: -200px;
  right: -200px;
  animation: float 20s infinite ease-in-out;
}

.shape-2 {
  width: 300px;
  height: 300px;
  background: var(--accent-blue);
  bottom: -150px;
  left: -150px;
  animation: float 25s infinite ease-in-out reverse;
}

.shape-3 {
  width: 250px;
  height: 250px;
  background: var(--accent-magenta);
  top: 50%;
  left: 10%;
  animation: float 30s infinite ease-in-out;
}

@keyframes float {
  0%, 100% {
    transform: translate(0, 0) scale(1);
  }
  33% {
    transform: translate(30px, -30px) scale(1.1);
  }
  66% {
    transform: translate(-20px, 20px) scale(0.9);
  }
}

/* ============================================
   TYPOGRAPHY
   ============================================ */

h1, h2, h3, h4, h5, h6 {
  font-weight: var(--font-weight-bold);
  line-height: 1.2;
  letter-spacing: -0.02em;
}

h1 {
  font-size: clamp(var(--text-5xl), 8vw, var(--text-8xl));
  font-weight: var(--font-weight-black);
  letter-spacing: -0.04em;
}

h2 {
  font-size: clamp(var(--text-4xl), 6vw, var(--text-6xl));
}

h3 {
  font-size: clamp(var(--text-3xl), 4vw, var(--text-4xl));
}

p {
  margin-bottom: var(--space-md);
  color: var(--text-secondary);
}

a {
  color: var(--accent-primary);
  text-decoration: none;
  transition: color var(--transition-base);
}

a:hover {
  color: var(--accent-primary-light);
}

/* ============================================
   HERO SECTION
   ============================================ */

.hero-section {
  position: relative;
  min-height: auto;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  padding: var(--space-4xl) var(--space-xl);
  margin: 0 auto;
  max-width: 1400px;
}

.hero-background {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: var(--gradient-hero);
  z-index: var(--z-base);
}

.hero-content {
  position: relative;
  z-index: var(--z-elevated);
  text-align: center;
  max-width: 1200px;
  animation: fadeInUp 1s ease-out;
}

.hero-title {
  font-size: clamp(var(--text-5xl), 10vw, var(--text-8xl));
  font-weight: var(--font-weight-black);
  letter-spacing: -0.05em;
  margin-bottom: var(--space-lg);
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1.1;
}

.hero-subtitle {
  font-size: clamp(var(--text-xl), 2.5vw, var(--text-3xl));
  color: var(--text-secondary);
  margin-bottom: var(--space-2xl);
  font-weight: var(--font-weight-medium);
  letter-spacing: -0.01em;
}

.hero-description {
  max-width: 900px;
  margin: 0 auto var(--space-2xl);
  text-align: left;
}

.hero-description-text {
  font-size: var(--text-base);
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: var(--space-lg);
  text-align: center;
}

.hero-features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--space-md);
  margin-bottom: var(--space-lg);
}

.hero-feature {
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-md);
  padding: var(--space-md);
  transition: all var(--transition-base);
}

.hero-feature:hover {
  background: rgba(255, 255, 255, 0.05);
  border-color: var(--accent-primary);
  transform: translateY(-4px);
}

.hero-feature h3 {
  font-size: var(--text-lg);
  font-weight: var(--font-weight-bold);
  color: var(--text-primary);
  margin-bottom: var(--space-xs);
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-feature p {
  font-size: var(--text-sm);
  color: var(--text-secondary);
  line-height: 1.6;
  margin: 0;
}

.hero-feature a {
  color: var(--accent-primary);
  text-decoration: underline;
  transition: color var(--transition-base);
}

.hero-feature a:hover {
  color: var(--accent-blue);
}

.hero-how-to {
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-md);
  padding: var(--space-lg);
  margin-bottom: var(--space-lg);
}

.hero-how-to h3 {
  font-size: var(--text-xl);
  font-weight: var(--font-weight-bold);
  color: var(--text-primary);
  margin-bottom: var(--space-md);
  text-align: center;
}

.hero-steps {
  list-style: none;
  counter-reset: step-counter;
  padding: 0;
  margin: 0;
}

.hero-steps li {
  counter-increment: step-counter;
  position: relative;
  padding-left: var(--space-3xl);
  margin-bottom: var(--space-sm);
  font-size: var(--text-sm);
  color: var(--text-secondary);
  line-height: 1.7;
}

.hero-steps li::before {
  content: counter(step-counter);
  position: absolute;
  left: 0;
  top: 0;
  width: 32px;
  height: 32px;
  background: var(--gradient-primary);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: var(--font-weight-bold);
  color: var(--text-primary);
  font-size: var(--text-base);
}

.hero-credits {
  text-align: center;
  padding-top: var(--space-md);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.hero-credit-text {
  font-size: var(--text-sm);
  color: var(--text-tertiary);
  margin-bottom: var(--space-sm);
  line-height: 1.6;
}

.hero-credit-label {
  color: var(--text-secondary);
  font-weight: var(--font-weight-semibold);
  margin-right: var(--space-xs);
}

.hero-credits a {
  color: var(--accent-primary);
  text-decoration: none;
  transition: color var(--transition-base);
  font-weight: var(--font-weight-medium);
}

.hero-credits a:hover {
  color: var(--accent-blue);
  text-decoration: underline;
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ============================================
   BUTTONS
   ============================================ */

.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-xl);
  font-size: var(--text-lg);
  font-weight: var(--font-weight-semibold);
  color: var(--text-primary);
  background: transparent;
  border: 2px solid var(--accent-primary);
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: all var(--transition-base);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  position: relative;
  overflow: hidden;
}

.btn::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: var(--gradient-primary);
  transition: left var(--transition-base);
  z-index: -1;
}

.btn:hover {
  border-color: var(--accent-primary-light);
  box-shadow: var(--glow-primary);
  transform: translateY(-2px);
}

.btn:hover::before {
  left: 0;
}

.btn-primary {
  background: var(--gradient-primary);
  border: none;
}

.btn-primary:hover {
  box-shadow: var(--glow-primary);
}

/* ============================================
   CSV UPLOAD SECTION
   ============================================ */

.upload-divider {
  margin: var(--space-2xl) 0 var(--space-xl);
  text-align: center;
  position: relative;
}

.upload-divider::before,
.upload-divider::after {
  content: '';
  position: absolute;
  top: 50%;
  width: 40%;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
}

.upload-divider::before {
  left: 0;
}

.upload-divider::after {
  right: 0;
}

.upload-divider span {
  display: inline-block;
  padding: 0 var(--space-md);
  color: var(--text-tertiary);
  font-size: var(--text-sm);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  background: var(--bg-primary);
}

.upload-section {
  width: 100%;
}

.upload-zone {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--space-3xl) var(--space-2xl);
  border: 2px dashed rgba(255, 255, 255, 0.2);
  border-radius: var(--radius-lg);
  background: rgba(255, 255, 255, 0.02);
  cursor: pointer;
  transition: all var(--transition-base);
  min-height: 180px;
  width: 100%;
}

.upload-zone:hover {
  border-color: var(--accent-primary);
  background: rgba(29, 185, 84, 0.05);
  box-shadow: var(--glow-primary-sm);
  transform: translateY(-2px);
}

.upload-zone.dragover {
  border-color: var(--accent-primary);
  background: rgba(29, 185, 84, 0.1);
  box-shadow: var(--glow-primary);
  transform: scale(1.02);
}

.upload-icon {
  width: 64px;
  height: 64px;
  margin-bottom: var(--space-lg);
  opacity: 0.8;
  display: flex;
  align-items: center;
  justify-content: center;
}

.upload-icon svg {
  width: 100%;
  height: 100%;
  stroke: var(--accent-primary);
  fill: none;
  stroke-width: 1.5;
}

.upload-text {
  font-size: var(--text-xl);
  font-weight: var(--font-weight-semibold);
  color: var(--text-primary);
  margin-bottom: var(--space-xs);
}

.upload-hint {
  font-size: var(--text-base);
  color: var(--text-tertiary);
}

.upload-status {
  margin-top: var(--space-md);
  padding: var(--space-md);
  border-radius: var(--radius-md);
  text-align: center;
  font-size: var(--text-sm);
}

.upload-status.success {
  background: rgba(29, 185, 84, 0.1);
  border: 1px solid var(--accent-primary);
  color: var(--accent-primary);
}

.upload-status.error {
  background: rgba(255, 107, 107, 0.1);
  border: 1px solid #ff6b6b;
  color: #ff6b6b;
}

.upload-status.processing {
  background: rgba(0, 212, 255, 0.1);
  border: 1px solid var(--accent-blue);
  color: var(--accent-blue);
}

.usage-options {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--space-xl);
  margin-bottom: var(--space-lg);
}

.usage-option h4 {
  font-size: var(--text-xl);
  font-weight: var(--font-weight-bold);
  color: var(--text-primary);
  margin-bottom: var(--space-xs);
}

.path-subtitle {
  font-size: var(--text-sm);
  color: var(--text-tertiary);
  margin-bottom: var(--space-md);
  font-weight: var(--font-weight-semibold);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.advanced-path h4 {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.simple-path h4 {
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.path-description {
  font-size: var(--text-sm);
  color: var(--text-secondary);
  margin-bottom: var(--space-md);
  line-height: 1.5;
}

.path-note {
  font-size: var(--text-sm);
  color: var(--accent-primary);
  margin-top: var(--space-md);
  padding-top: var(--space-md);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
}

/* Actions Container - Side by Side Layout */
.actions-container {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: var(--space-2xl);
  align-items: start;
  margin: var(--space-3xl) 0;
  max-width: 900px;
  margin-left: auto;
  margin-right: auto;
}

.action-column {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  width: 100%;
}

.action-column .btn-primary {
  width: 100%;
  max-width: 400px;
  padding: var(--space-lg) var(--space-2xl);
  font-size: var(--text-lg);
}

.action-label {
  font-size: var(--text-base);
  color: var(--text-primary);
  margin-bottom: var(--space-lg);
  font-weight: var(--font-weight-bold);
  letter-spacing: 0.02em;
}

.divider-vertical {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  position: relative;
  padding: 0 var(--space-md);
  min-height: 200px;
}

.divider-vertical::before,
.divider-vertical::after {
  content: '';
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  width: 1px;
  height: 45%;
  background: linear-gradient(180deg, transparent, rgba(255, 255, 255, 0.2), transparent);
}

.divider-vertical::before {
  top: 0;
}

.divider-vertical::after {
  bottom: 0;
}

.divider-vertical span {
  display: inline-block;
  padding: var(--space-sm) var(--space-md);
  color: var(--text-tertiary);
  font-size: var(--text-sm);
  text-transform: lowercase;
  background: var(--bg-primary);
  border-radius: var(--radius-full);
  z-index: 1;
}

/* Responsive adjustments */
@media (max-width: 768px) {
  .actions-container {
    grid-template-columns: 1fr;
    gap: var(--space-xl);
  }
  
  .divider-vertical {
    flex-direction: row;
    min-height: auto;
    padding: var(--space-md) 0;
    width: 100%;
  }
  
  .divider-vertical::before,
  .divider-vertical::after {
    width: 40%;
    height: 1px;
    top: 50%;
    transform: translateY(-50%);
  }
  
  .divider-vertical::before {
    left: 0;
  }
  
  .divider-vertical::after {
    right: 0;
    left: auto;
  }
}

.upload-note {
  font-size: var(--text-sm);
  color: var(--text-tertiary);
  padding: var(--space-md);
  background: rgba(255, 255, 255, 0.03);
  border-left: 3px solid var(--accent-primary);
  border-radius: var(--radius-sm);
  margin-top: var(--space-lg);
  line-height: 1.6;
}

.upload-note strong {
  color: var(--text-secondary);
}

.upload-note a {
  color: var(--accent-primary);
  text-decoration: underline;
}

/* ============================================
   PLAYLIST CARDS
   ============================================ */

.playlists-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-md);
  padding: var(--space-xl) 0;
  margin: 0 auto;
}

@media (max-width: 1200px) {
  .playlists-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

@media (max-width: 768px) {
  .playlists-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 480px) {
  .playlists-grid {
    grid-template-columns: 1fr;
  }
}

.playlists-controls {
  background: var(--bg-elevated);
  border-radius: var(--radius-md);
  padding: var(--space-md);
  border: 1px solid rgba(255, 255, 255, 0.05);
}

.playlist-search {
  flex: 1;
  padding: var(--space-sm) var(--space-md);
  background: var(--bg-secondary);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-size: var(--text-base);
  transition: all var(--transition-base);
  min-width: 200px;
}

.playlist-search:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px rgba(29, 185, 84, 0.2);
  background: var(--bg-elevated);
}

.playlist-search::placeholder {
  color: var(--text-tertiary);
}

.playlist-sort {
  padding: var(--space-sm) var(--space-md);
  background: var(--bg-secondary);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-size: var(--text-base);
  cursor: pointer;
  transition: all var(--transition-base);
}

.playlist-sort:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px rgba(29, 185, 84, 0.2);
  background: var(--bg-elevated);
}

.playlist-sort option {
  background: var(--bg-elevated);
  color: var(--text-primary);
}

.playlist-card {
  position: relative;
  background: var(--bg-elevated);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: all var(--transition-base);
  cursor: pointer;
  border: 1px solid rgba(255, 255, 255, 0.05);
}

.playlist-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: var(--gradient-primary);
  opacity: 0;
  transition: opacity var(--transition-base);
  z-index: var(--z-base);
}

.playlist-card:hover {
  transform: translateY(-8px) scale(1.02);
  box-shadow: var(--shadow-lg), var(--glow-primary);
  border-color: var(--accent-primary);
}

.playlist-card:hover::before {
  opacity: 0.1;
}

.playlist-cover {
  width: 100%;
  aspect-ratio: 1;
  object-fit: cover;
  display: block;
  transition: transform var(--transition-slow);
}

.playlist-card:hover .playlist-cover {
  transform: scale(1.1);
}

.playlist-info {
  padding: var(--space-lg);
  position: relative;
  z-index: var(--z-elevated);
}

.playlist-name {
  font-size: var(--text-lg);
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--space-xs);
  color: var(--text-primary);
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.playlist-owner {
  font-size: var(--text-sm);
  color: var(--text-tertiary);
  margin-bottom: var(--space-sm);
}

.playlist-meta {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: var(--text-xs);
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.playlist-actions {
  display: flex;
  gap: var(--space-sm);
  margin-top: var(--space-md);
  opacity: 0;
  transform: translateY(10px);
  transition: all var(--transition-base);
}

.playlist-card:hover .playlist-actions {
  opacity: 1;
  transform: translateY(0);
}

.btn-action {
  flex: 1;
  padding: var(--space-sm) var(--space-md);
  font-size: var(--text-sm);
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  cursor: pointer;
  transition: all var(--transition-fast);
  text-transform: none;
  letter-spacing: 0;
}

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

.btn-action.active {
  background: var(--accent-primary);
  border-color: var(--accent-primary);
  color: var(--text-primary);
}

/* ============================================
   HEADER & NAVIGATION
   ============================================ */

.main-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  padding: var(--space-lg) var(--space-xl);
  background: rgba(10, 10, 10, 0.8);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
  z-index: var(--z-sticky);
  transform: translateY(-100%);
  transition: transform var(--transition-base);
}

.main-header.visible {
  transform: translateY(0);
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: 1600px;
  margin: 0 auto;
}

.logo {
  font-size: var(--text-2xl);
  font-weight: var(--font-weight-black);
  color: var(--text-primary);
  text-decoration: none;
}

.logout-btn {
  padding: var(--space-sm) var(--space-md);
  font-size: var(--text-sm);
}

/* ============================================
   UTILITY CLASSES
   ============================================ */

.container {
  max-width: 1600px;
  margin: 0 auto;
  padding: 0 var(--space-xl);
}

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

.fade-in {
  animation: fadeIn 0.6s ease-out;
}

@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

/* ============================================
   LOADING SPINNER
   ============================================ */

.spinner {
  position: relative;
  width: 100px;
  height: 100px;
  margin: var(--space-4xl) auto;
}

.spinner::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 60px;
  height: 60px;
  margin: -30px 0 0 -30px;
  border: 3px solid rgba(29, 185, 84, 0.2);
  border-top-color: var(--accent-primary);
  border-radius: 50%;
  animation: spinner 1s linear infinite;
}

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

/* ============================================
   ERROR MESSAGES
   ============================================ */

.error-message {
  background: rgba(255, 0, 0, 0.1);
  border: 1px solid rgba(255, 0, 0, 0.3);
  border-radius: var(--radius-md);
  padding: var(--space-lg);
  margin: var(--space-lg) 0;
  color: #ff6b6b;
}

/* ============================================
   LIST VIEW
   ============================================ */

.playlists-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
  padding: var(--space-xl) 0;
  margin: 0 auto;
}

.playlist-list-item {
  position: relative;
  background: var(--bg-elevated);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: all var(--transition-base);
  cursor: pointer;
  border: 1px solid rgba(255, 255, 255, 0.05);
  display: flex;
  align-items: center;
  gap: var(--space-lg);
  padding: var(--space-lg);
}

.playlist-list-item::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: var(--gradient-primary);
  opacity: 0;
  transition: opacity var(--transition-base);
  z-index: var(--z-base);
}

.playlist-list-item:hover {
  transform: translateX(8px);
  box-shadow: var(--shadow-lg), var(--glow-primary);
  border-color: var(--accent-primary);
}

.playlist-list-item:hover::before {
  opacity: 0.1;
}

.playlist-list-cover {
  width: 60px;
  height: 60px;
  border-radius: var(--radius-sm);
  object-fit: cover;
  flex-shrink: 0;
}

.playlist-list-content {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
  flex: 1;
  position: relative;
  z-index: var(--z-elevated);
}

.playlist-list-info {
  flex: 1;
  min-width: 0;
}

.playlist-list-info .playlist-name {
  font-size: var(--text-lg);
  margin-bottom: var(--space-xs);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.playlist-list-info .playlist-owner {
  font-size: var(--text-sm);
  margin-bottom: var(--space-xs);
}

.playlist-list-info .playlist-meta {
  font-size: var(--text-xs);
}

.playlist-list-item .playlist-actions {
  opacity: 1;
  transform: translateY(0);
  display: flex;
  gap: var(--space-sm);
  flex-shrink: 0;
}

/* ============================================
   RESPONSIVE DESIGN
   ============================================ */

@media (max-width: 1024px) {
  .playlists-grid {
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    gap: var(--space-md);
  }
}

@media (max-width: 768px) {
  .hero-section {
    min-height: auto;
    padding: var(--space-lg);
    padding-top: var(--space-4xl);
  }
  
  .hero-description {
    text-align: center;
  }
  
  .hero-features {
    grid-template-columns: 1fr;
    gap: var(--space-md);
  }
  
  .hero-how-to {
    padding: var(--space-lg);
  }
  
  .hero-steps li {
    padding-left: var(--space-2xl);
    font-size: var(--text-sm);
  }
  
  .hero-steps li::before {
    width: 28px;
    height: 28px;
    font-size: var(--text-sm);
  }
  
  .playlists-grid {
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: var(--space-md);
    padding: var(--space-lg) var(--space-sm);
  }
  
  .playlist-card {
    border-radius: var(--radius-md);
  }
  
  .playlist-actions {
    opacity: 1;
    transform: translateY(0);
  }
  
  .playlist-list-item {
    flex-direction: column;
    align-items: flex-start;
    padding: var(--space-md);
  }
  
  .playlist-list-content {
    width: 100%;
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-sm);
  }
  
  .playlist-list-item .playlist-actions {
    width: 100%;
    justify-content: flex-end;
  }
}

@media (max-width: 480px) {
  .playlists-grid {
    grid-template-columns: 1fr;
  }
  
  .hero-title {
    font-size: var(--text-4xl);
  }
  
  .hero-subtitle {
    font-size: var(--text-lg);
  }
  
  .playlists-controls {
    flex-direction: column;
  }
  
  .playlist-search {
    width: 100%;
  }
}

/* ============================================
   FOOTER
   ============================================ */

.main-footer {
  background: var(--bg-elevated);
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  padding: var(--space-xl) var(--space-xl);
  margin-top: var(--space-4xl);
}

.footer-content {
  max-width: 1400px;
  margin: 0 auto;
  text-align: center;
}

.footer-text {
  font-size: var(--text-base);
  color: var(--text-secondary);
  margin-bottom: var(--space-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  flex-wrap: wrap;
}

.footer-text span {
  color: var(--text-primary);
  font-weight: var(--font-weight-semibold);
}

.footer-text a {
  color: var(--accent-primary);
  text-decoration: none;
  transition: color var(--transition-base);
}

.footer-text a:hover {
  color: var(--accent-blue);
  text-decoration: underline;
}

.footer-credit {
  font-size: var(--text-sm);
  color: var(--text-tertiary);
}

.footer-credit a {
  color: var(--accent-primary);
  text-decoration: none;
  transition: color var(--transition-base);
}

.footer-credit a:hover {
  color: var(--accent-blue);
  text-decoration: underline;
}