/* ==========================================================================
   PlayPulse - YouTube Playlist Duration Calculator
   Ultra-Modern, Sexy Design System
   ========================================================================== */

:root {
  /* Color Palette - Dark Luxe (Default) */
  --bg-base: #07090e;
  --bg-surface: #0e131f;
  --bg-surface-elevated: #141b2d;
  --bg-card: rgba(17, 24, 39, 0.75);
  --bg-card-hover: rgba(26, 36, 56, 0.85);
  --bg-glass: rgba(15, 23, 42, 0.65);
  --bg-input: rgba(10, 15, 26, 0.8);
  
  --border-subtle: rgba(255, 255, 255, 0.08);
  --border-medium: rgba(255, 255, 255, 0.15);
  --border-focus: rgba(255, 0, 51, 0.5);
  
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-tertiary: #64748b;
  --text-inverse: #090d16;
  
  /* Brand Accents */
  --brand-yt: #ff0033;
  --brand-yt-hover: #ff2a55;
  --brand-gradient: linear-gradient(135deg, #ff0033 0%, #ff4b4b 50%, #8b5cf6 100%);
  --brand-glow: 0 0 35px rgba(255, 0, 51, 0.35);
  
  --accent-purple: #8b5cf6;
  --accent-cyan: #06b6d4;
  --accent-emerald: #10b981;
  --accent-amber: #f59e0b;
  
  /* Shadows & Glassmorphism */
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 8px 24px -4px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 20px 40px -10px rgba(0, 0, 0, 0.6);
  --shadow-glow: 0 0 50px -10px rgba(255, 0, 51, 0.25);
  --glass-blur: blur(20px);
  
  /* Radii & Transitions */
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-xl: 28px;
  --radius-full: 9999px;
  
  --transition-fast: 0.15s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-spring: 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

[data-theme="light"] {
  --bg-base: #f8fafc;
  --bg-surface: #ffffff;
  --bg-surface-elevated: #f1f5f9;
  --bg-card: rgba(255, 255, 255, 0.85);
  --bg-card-hover: rgba(255, 255, 255, 0.98);
  --bg-glass: rgba(255, 255, 255, 0.75);
  --bg-input: rgba(248, 250, 252, 0.9);
  
  --border-subtle: rgba(0, 0, 0, 0.08);
  --border-medium: rgba(0, 0, 0, 0.14);
  --border-focus: rgba(255, 0, 51, 0.4);
  
  --text-primary: #0f172a;
  --text-secondary: #334155;
  --text-tertiary: #64748b;
  --text-inverse: #ffffff;
  
  --brand-glow: 0 0 30px rgba(255, 0, 51, 0.2);
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 10px 30px -5px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 25px 50px -12px rgba(0, 0, 0, 0.12);
  --shadow-glow: 0 10px 40px -10px rgba(255, 0, 51, 0.15);
}

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

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 5.5rem;
  font-size: 16px;
}

:focus-visible {
  outline: 2px solid var(--brand-yt);
  outline-offset: 2px;
}

.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;
}

body {
  font-family: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background-color: var(--bg-base);
  color: var(--text-primary);
  min-height: 100vh;
  line-height: 1.6;
  overflow-x: hidden;
  position: relative;
  transition: background-color var(--transition-normal), color var(--transition-normal);
  -webkit-font-smoothing: antialiased;
}

/* Background Atmosphere */
.ambient-glow {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  overflow: hidden;
}

.glow-orb-1 {
  position: absolute;
  top: -15%;
  left: 20%;
  width: 600px;
  height: 600px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(255, 0, 51, 0.18) 0%, rgba(255, 0, 51, 0) 70%);
  filter: blur(80px);
  animation: pulseOrb 12s ease-in-out infinite alternate;
}

.glow-orb-2 {
  position: absolute;
  top: 30%;
  right: -10%;
  width: 500px;
  height: 500px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(139, 92, 246, 0.15) 0%, rgba(139, 92, 246, 0) 70%);
  filter: blur(90px);
  animation: pulseOrb 16s ease-in-out infinite alternate-reverse;
}

.glow-orb-3 {
  position: absolute;
  bottom: 5%;
  left: -5%;
  width: 450px;
  height: 450px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(6, 182, 212, 0.12) 0%, rgba(6, 182, 212, 0) 70%);
  filter: blur(80px);
}

.ambient-grid {
  position: absolute;
  inset: 0;
  background-image: 
    linear-gradient(to right, var(--border-subtle) 1px, transparent 1px),
    linear-gradient(to bottom, var(--border-subtle) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: radial-gradient(ellipse 60% 50% at 50% 30%, #000 70%, transparent 100%);
  -webkit-mask-image: radial-gradient(ellipse 60% 50% at 50% 30%, #000 70%, transparent 100%);
  opacity: 0.35;
}

@keyframes pulseOrb {
  0% { transform: scale(1) translate(0, 0); opacity: 0.6; }
  50% { transform: scale(1.15) translate(30px, 20px); opacity: 0.9; }
  100% { transform: scale(0.95) translate(-20px, 30px); opacity: 0.7; }
}

/* ==========================================================================
   Layout & Container
   ========================================================================== */

.app-wrapper {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.container {
  width: 100%;
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* ==========================================================================
   Navigation Bar
   ========================================================================== */

.navbar {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  background: var(--bg-glass);
  border-bottom: 1px solid var(--border-subtle);
  padding: 0.85rem 0;
  transition: all var(--transition-normal);
}

.nav-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: var(--text-primary);
  font-weight: 800;
  font-size: 1.25rem;
  letter-spacing: -0.03em;
}

.logo-icon-wrapper {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  background: var(--brand-gradient);
  border-radius: var(--radius-sm);
  box-shadow: 0 0 15px rgba(255, 0, 51, 0.5);
  color: #ffffff;
  transition: transform var(--transition-spring);
}

.brand-logo:hover .logo-icon-wrapper {
  transform: scale(1.08) rotate(-3deg);
}

.logo-text {
  background: linear-gradient(135deg, var(--text-primary) 30%, var(--text-secondary) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.logo-text span {
  background: var(--brand-gradient);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.nav-badges {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.version-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.25rem 0.65rem;
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-full);
  color: var(--text-secondary);
}

.status-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent-emerald);
  box-shadow: 0 0 8px var(--accent-emerald);
  animation: pulseDot 2s infinite;
}

@keyframes pulseDot {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.4; transform: scale(0.8); }
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.bmac-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.42rem 0.85rem;
  background: #FFDD00;
  color: #000000;
  font-family: 'Plus Jakarta Sans', sans-serif;
  font-size: 0.8rem;
  font-weight: 700;
  border-radius: var(--radius-full);
  text-decoration: none;
  border: 1px solid rgba(0, 0, 0, 0.1);
  box-shadow: 0 2px 10px rgba(255, 221, 0, 0.25);
  transition: transform var(--transition-fast), box-shadow var(--transition-fast), filter var(--transition-fast);
}

.bmac-btn:hover {
  transform: translateY(-1.5px);
  box-shadow: 0 4px 16px rgba(255, 221, 0, 0.45);
  filter: brightness(1.05);
  color: #000000;
}

.bmac-btn svg {
  flex-shrink: 0;
}

@media (max-width: 520px) {
  .bmac-btn span {
    display: none;
  }
  .bmac-btn {
    padding: 0.45rem 0.6rem;
  }
}

.footer-bmac-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  color: #FFDD00;
  font-weight: 700;
  text-decoration: none;
  transition: opacity var(--transition-fast), transform var(--transition-fast);
}

.footer-bmac-link:hover {
  opacity: 0.9;
  transform: translateY(-1px);
  color: #FFE642;
}

.footer-author-link {
  color: var(--text-primary);
  text-decoration: none;
  font-weight: 600;
  transition: color var(--transition-fast);
}

.footer-author-link:hover {
  color: var(--brand-yt);
}

.footer-separator {
  color: var(--text-tertiary);
  opacity: 0.5;
}

.icon-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-subtle);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
}

.icon-btn:hover {
  background: var(--bg-card-hover);
  color: var(--text-primary);
  border-color: var(--border-medium);
  transform: translateY(-1px);
}

/* ==========================================================================
   Hero Section
   ========================================================================== */

.hero-section {
  padding: 3.5rem 0 2rem;
  text-align: center;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 0.95rem;
  border-radius: var(--radius-full);
  background: rgba(255, 0, 51, 0.1);
  border: 1px solid rgba(255, 0, 51, 0.25);
  color: var(--brand-yt-hover);
  font-size: 0.825rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  text-transform: uppercase;
  margin-bottom: 1.25rem;
  box-shadow: 0 0 20px rgba(255, 0, 51, 0.15);
  animation: floatBadge 4s ease-in-out infinite;
}

@keyframes floatBadge {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-4px); }
}

.hero-title {
  font-size: clamp(2.2rem, 5vw, 3.75rem);
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -0.035em;
  margin-bottom: 1.25rem;
  color: var(--text-primary);
}

.hero-title-gradient {
  background: var(--brand-gradient);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  display: inline-block;
}

.hero-subtitle {
  font-size: clamp(1rem, 2vw, 1.2rem);
  color: var(--text-secondary);
  max-width: 650px;
  margin: 0 auto 2.5rem;
  font-weight: 400;
}

/* ==========================================================================
   Input / Command Bar
   ========================================================================== */

.search-container {
  max-width: 780px;
  margin: 0 auto 1.5rem;
  position: relative;
}

.search-box-glass {
  background: var(--bg-card);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border: 1px solid var(--border-medium);
  border-radius: var(--radius-xl);
  padding: 0.6rem;
  box-shadow: var(--shadow-lg);
  transition: all var(--transition-normal);
  display: flex;
  align-items: center;
  gap: 0.5rem;
  position: relative;
}

.search-box-glass:focus-within {
  border-color: var(--brand-yt);
  box-shadow: var(--shadow-glow), var(--shadow-lg);
  transform: translateY(-2px);
}

.search-icon-left {
  display: flex;
  align-items: center;
  justify-content: center;
  padding-left: 0.85rem;
  color: var(--brand-yt);
}

.search-input {
  flex: 1;
  background: transparent;
  border: none;
  outline: none;
  font-family: inherit;
  font-size: 1.05rem;
  color: var(--text-primary);
  padding: 0.65rem 0.5rem;
  min-width: 0;
}

.search-input::placeholder {
  color: var(--text-tertiary);
  font-size: 0.95rem;
}

.input-tool-actions {
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.tool-btn {
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-subtle);
  color: var(--text-secondary);
  border-radius: var(--radius-sm);
  padding: 0.45rem 0.75rem;
  font-size: 0.75rem;
  font-weight: 600;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  transition: all var(--transition-fast);
}

.tool-btn:hover {
  background: var(--bg-card-hover);
  color: var(--text-primary);
  border-color: var(--border-medium);
}

.btn-primary {
  background: var(--brand-gradient);
  color: #ffffff;
  border: none;
  border-radius: var(--radius-lg);
  padding: 0.85rem 1.6rem;
  font-size: 1rem;
  font-weight: 700;
  font-family: inherit;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  transition: all var(--transition-fast);
  box-shadow: 0 4px 15px rgba(255, 0, 51, 0.4);
  white-space: nowrap;
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(255, 0, 51, 0.55);
}

.btn-primary:active {
  transform: translateY(0);
}

.btn-primary:disabled {
  opacity: 0.65;
  cursor: not-allowed;
  transform: none;
}

/* Spinner */
.spinner {
  display: inline-block;
  width: 18px;
  height: 18px;
  border: 2.5px solid rgba(255, 255, 255, 0.3);
  border-radius: 50%;
  border-top-color: #ffffff;
  animation: spin 0.8s linear infinite;
}

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

/* ==========================================================================
   Quick Preset Chips & Recents
   ========================================================================== */

.preset-container {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 2.5rem;
}

.preset-label {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-right: 0.25rem;
}

.preset-chip {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-full);
  padding: 0.35rem 0.85rem;
  font-size: 0.825rem;
  font-weight: 500;
  color: var(--text-secondary);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  transition: all var(--transition-fast);
}

.preset-chip:hover {
  background: var(--bg-card-hover);
  color: var(--text-primary);
  border-color: var(--border-medium);
  transform: translateY(-1px);
}

.recents-bar {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: -1.5rem;
  margin-bottom: 2rem;
}

/* ==========================================================================
   Results Dashboard
   ========================================================================== */

#resultsDashboard {
  display: none;
  animation: fadeInDashboard 0.4s cubic-bezier(0.16, 1, 0.3, 1);
  margin-bottom: 4rem;
}

@keyframes fadeInDashboard {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Hero Showcase Card */
.showcase-card {
  background: var(--bg-card);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border: 1px solid var(--border-medium);
  border-radius: var(--radius-xl);
  padding: 2rem;
  box-shadow: var(--shadow-lg);
  margin-bottom: 1.75rem;
  position: relative;
  overflow: hidden;
}

.showcase-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--brand-gradient);
}

.showcase-header {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 1.75rem;
  align-items: center;
}

@media (max-width: 768px) {
  .showcase-header {
    grid-template-columns: 1fr;
  }
}

.playlist-thumb-wrapper {
  position: relative;
  width: 220px;
  aspect-ratio: 16/9;
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-md);
  background: var(--bg-surface);
}

.playlist-thumb-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--transition-normal);
}

.playlist-thumb-wrapper:hover .playlist-thumb-img {
  transform: scale(1.05);
}

.thumb-count-overlay {
  position: absolute;
  bottom: 0.5rem;
  right: 0.5rem;
  background: rgba(0, 0, 0, 0.85);
  color: #ffffff;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 0.2rem 0.5rem;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  gap: 0.3rem;
}

.playlist-meta {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.channel-tag {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.verified-badge {
  color: var(--accent-cyan);
}

.playlist-main-title {
  font-size: clamp(1.3rem, 2.5vw, 1.85rem);
  font-weight: 800;
  line-height: 1.2;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

.playlist-quick-stats {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 1.25rem;
  margin-top: 0.25rem;
}

.quick-stat-item {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.875rem;
  color: var(--text-tertiary);
  font-weight: 500;
}

.quick-stat-item strong {
  color: var(--text-primary);
  font-weight: 700;
}

.action-bar {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-top: 1rem;
  flex-wrap: wrap;
}

.btn-secondary {
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-subtle);
  color: var(--text-primary);
  border-radius: var(--radius-md);
  padding: 0.55rem 1rem;
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  transition: all var(--transition-fast);
  text-decoration: none;
}

.btn-secondary:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-medium);
  transform: translateY(-1px);
}

/* ==========================================================================
   Hero Time Display Banner
   ========================================================================== */

.hero-duration-banner {
  background: linear-gradient(135deg, rgba(255, 0, 51, 0.1) 0%, rgba(139, 92, 246, 0.08) 100%);
  border: 1px solid rgba(255, 0, 51, 0.25);
  border-radius: var(--radius-xl);
  padding: 2.25rem 2rem;
  text-align: center;
  margin-bottom: 1.75rem;
  position: relative;
  overflow: hidden;
}

.duration-banner-label {
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--brand-yt-hover);
  margin-bottom: 0.75rem;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}

.digital-time-clock {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  margin-bottom: 0.85rem;
  flex-wrap: wrap;
}

.time-digit-block {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.digit-value {
  font-family: 'JetBrains Mono', monospace;
  font-size: clamp(2.4rem, 6vw, 4.2rem);
  font-weight: 800;
  line-height: 1;
  color: var(--text-primary);
  background: var(--bg-card);
  border: 1px solid var(--border-medium);
  border-radius: var(--radius-md);
  padding: 0.4rem 0.85rem;
  min-width: 90px;
  text-align: center;
  box-shadow: var(--shadow-md);
}

.digit-unit {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-top: 0.4rem;
}

.time-separator {
  font-family: 'JetBrains Mono', monospace;
  font-size: clamp(2rem, 5vw, 3rem);
  font-weight: 700;
  color: var(--text-tertiary);
  margin-bottom: 1.2rem;
}

.duration-human-readable {
  font-size: 1.1rem;
  color: var(--text-secondary);
  font-weight: 500;
}

.duration-human-readable span {
  color: var(--text-primary);
  font-weight: 700;
}

/* ==========================================================================
   Speed Matrix & Custom Slider
   ========================================================================== */

.section-header-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.25rem;
}

.section-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.speeds-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.speed-card {
  background: var(--bg-card);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 1.25rem 1rem;
  text-align: center;
  cursor: pointer;
  transition: all var(--transition-fast);
  position: relative;
  overflow: hidden;
  font-family: inherit;
  font-size: inherit;
  color: inherit;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  width: 100%;
}

.speed-card:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-medium);
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}

.speed-card.active {
  border-color: var(--brand-yt);
  background: linear-gradient(135deg, rgba(255, 0, 51, 0.12) 0%, rgba(139, 92, 246, 0.08) 100%);
  box-shadow: 0 0 25px rgba(255, 0, 51, 0.25);
}

.speed-badge {
  display: inline-block;
  font-family: 'JetBrains Mono', monospace;
  font-size: 1.15rem;
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: 0.35rem;
}

.speed-card.active .speed-badge {
  color: var(--brand-yt-hover);
}

.speed-time {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 0.4rem;
}

.speed-saved {
  font-size: 0.75rem;
  font-weight: 700;
  padding: 0.2rem 0.5rem;
  border-radius: var(--radius-full);
  background: rgba(16, 185, 129, 0.15);
  color: var(--accent-emerald);
  display: inline-block;
}

.speed-popular-tag {
  position: absolute;
  top: 0;
  right: 0;
  background: var(--brand-gradient);
  color: #ffffff;
  font-size: 0.65rem;
  font-weight: 800;
  padding: 0.15rem 0.5rem;
  border-bottom-left-radius: var(--radius-sm);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

/* Custom Interactive Slider Box */
.custom-speed-box {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 1.25rem 1.5rem;
  margin-bottom: 1.75rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  flex-wrap: wrap;
}

.custom-speed-info {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.custom-speed-slider-wrap {
  flex: 1;
  min-width: 200px;
  display: flex;
  align-items: center;
  gap: 1rem;
}

.range-slider {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 6px;
  border-radius: 5px;
  background: var(--bg-surface-elevated);
  outline: none;
}

.range-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--brand-yt);
  cursor: pointer;
  box-shadow: 0 0 10px rgba(255, 0, 51, 0.7);
  transition: transform var(--transition-fast);
}

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

.custom-speed-val {
  font-family: 'JetBrains Mono', monospace;
  font-weight: 700;
  color: var(--brand-yt);
  font-size: 1.1rem;
  min-width: 50px;
}

/* ==========================================================================
   Insights Grid (Cards)
   ========================================================================== */

.insights-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
  margin-bottom: 1.75rem;
}

.insight-card {
  background: var(--bg-card);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  transition: all var(--transition-fast);
}

.insight-card:hover {
  border-color: var(--border-medium);
  transform: translateY(-2px);
}

.insight-card-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  color: var(--text-tertiary);
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.insight-icon {
  width: 28px;
  height: 28px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-surface-elevated);
}

.insight-value {
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

.insight-subtext {
  font-size: 0.8rem;
  color: var(--text-secondary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* ==========================================================================
   Study Planner & Daily Schedule Estimator
   ========================================================================== */

.study-planner-card {
  background: var(--bg-card);
  backdrop-filter: var(--glass-blur);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-xl);
  padding: 1.5rem 1.75rem;
  margin-bottom: 1.75rem;
}

.study-planner-body {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
  align-items: center;
  margin-top: 1rem;
}

@media (max-width: 640px) {
  .study-planner-body {
    grid-template-columns: 1fr;
  }
}

.study-presets {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  margin-top: 0.5rem;
}

.study-chip {
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 0.4rem 0.8rem;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.study-chip.active, .study-chip:hover {
  background: var(--brand-yt);
  color: #ffffff;
  border-color: var(--brand-yt);
}

.study-result-box {
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-medium);
  border-radius: var(--radius-lg);
  padding: 1rem 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.study-result-title {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--text-tertiary);
  text-transform: uppercase;
}

.study-result-days {
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--text-primary);
}

.study-result-days span {
  color: var(--accent-emerald);
}

/* ==========================================================================
   Range Filter Box (Subset Videos)
   ========================================================================== */

.range-filter-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 1.25rem 1.5rem;
  margin-bottom: 1.75rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}

.range-inputs {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.range-num-input {
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 0.4rem 0.6rem;
  width: 70px;
  text-align: center;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.95rem;
  color: var(--text-primary);
  outline: none;
}

.range-num-input:focus {
  border-color: var(--brand-yt);
}

/* ==========================================================================
   Video List Drawer / Accordion
   ========================================================================== */

.video-list-container {
  background: var(--bg-card);
  backdrop-filter: var(--glass-blur);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-xl);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
}

.video-list-header {
  width: 100%;
  padding: 1.25rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--bg-surface);
  border: none;
  border-bottom: 1px solid var(--border-subtle);
  cursor: pointer;
  user-select: none;
  font-family: inherit;
  font-size: inherit;
  color: inherit;
  text-align: left;
  transition: background var(--transition-fast);
}

.video-list-header:hover {
  background: var(--bg-card-hover);
}

.video-list-title-text {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-primary);
}

.video-list-title-group {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.list-count-badge {
  background: var(--brand-yt);
  color: #ffffff;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 0.2rem 0.55rem;
  border-radius: var(--radius-full);
}

.video-search-wrap {
  padding: 0.85rem 1.5rem;
  border-bottom: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.video-search-input {
  flex: 1;
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 0.5rem 0.85rem;
  font-size: 0.9rem;
  color: var(--text-primary);
  outline: none;
}

.video-search-input:focus {
  border-color: var(--brand-yt);
}

.video-items-scroll {
  max-height: 480px;
  overflow-y: auto;
  padding: 0.5rem 0;
}

.video-items-scroll::-webkit-scrollbar {
  width: 6px;
}

.video-items-scroll::-webkit-scrollbar-track {
  background: transparent;
}

.video-items-scroll::-webkit-scrollbar-thumb {
  background: var(--border-medium);
  border-radius: 3px;
}

.video-item {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 0.75rem 1.5rem;
  border-bottom: 1px solid var(--border-subtle);
  transition: background var(--transition-fast);
}

.video-item:last-child {
  border-bottom: none;
}

.video-item:hover {
  background: var(--bg-surface-elevated);
}

.video-pos {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--text-tertiary);
  min-width: 26px;
}

.video-thumb-small {
  width: 80px;
  aspect-ratio: 16/9;
  border-radius: var(--radius-sm);
  object-fit: cover;
  background: var(--bg-surface-elevated);
}

.video-title-wrap {
  flex: 1;
  min-width: 0;
}

.video-title {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  display: block;
  text-decoration: none;
}

.video-title:hover {
  color: var(--brand-yt-hover);
}

.video-item-dur {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.825rem;
  font-weight: 600;
  padding: 0.25rem 0.6rem;
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  white-space: nowrap;
}

/* ==========================================================================
   Error & Empty States
   ========================================================================== */

.error-card {
  display: none;
  max-width: 780px;
  margin: 0 auto 2.5rem;
  background: rgba(239, 68, 68, 0.1);
  border: 1px solid rgba(239, 68, 68, 0.3);
  border-radius: var(--radius-lg);
  padding: 1.25rem 1.5rem;
  color: #f87171;
  animation: shake 0.4s ease-in-out;
}

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  20%, 60% { transform: translateX(-6px); }
  40%, 80% { transform: translateX(6px); }
}

.error-content {
  display: flex;
  align-items: center;
  gap: 0.85rem;
}

/* ==========================================================================
   Toast Notifications
   ========================================================================== */

.toast-container {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  z-index: 100;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  pointer-events: none;
}

.toast {
  pointer-events: auto;
  background: var(--bg-surface-elevated);
  backdrop-filter: var(--glass-blur);
  border: 1px solid var(--border-medium);
  border-radius: var(--radius-md);
  padding: 0.75rem 1.25rem;
  color: var(--text-primary);
  font-size: 0.875rem;
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 0.6rem;
  box-shadow: var(--shadow-lg);
  animation: slideToast 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

@keyframes slideToast {
  from { opacity: 0; transform: translateY(15px) scale(0.95); }
  to { opacity: 1; transform: translateY(0) scale(1); }
}

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

.app-footer {
  margin-top: auto;
  border-top: 1px solid var(--border-subtle);
  background: var(--bg-glass);
  backdrop-filter: var(--glass-blur);
  padding: 2rem 0;
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-tertiary);
}

.footer-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1.25rem;
}

.footer-left {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  text-align: left;
}

.footer-compliance {
  font-size: 0.75rem;
  color: var(--text-tertiary);
  max-width: 580px;
  line-height: 1.5;
}

.footer-compliance a {
  color: var(--text-secondary);
  text-decoration: underline;
}

.footer-compliance a:hover {
  color: var(--brand-yt);
}

.footer-modal-link {
  background: transparent;
  border: none;
  color: var(--text-secondary);
  font-size: 0.85rem;
  cursor: pointer;
  padding: 0;
  text-decoration: underline;
  transition: color var(--transition-fast);
}

.footer-modal-link:hover {
  color: var(--brand-yt);
}

/* Legal Modal */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.75);
  backdrop-filter: blur(8px);
  z-index: 1000;
  display: none;
  align-items: center;
  justify-content: center;
  padding: 1rem;
}

.modal-backdrop.active {
  display: flex;
}

.modal-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-medium);
  border-radius: var(--radius-lg);
  max-width: 540px;
  width: 100%;
  max-height: 85vh;
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow-lg);
  overflow: hidden;
  animation: scaleUpModal 0.25s cubic-bezier(0.16, 1, 0.3, 1);
}

@keyframes scaleUpModal {
  from { opacity: 0; transform: scale(0.92); }
  to { opacity: 1; transform: scale(1); }
}

.modal-header {
  padding: 1.25rem 1.5rem;
  border-bottom: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.modal-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-primary);
}

.modal-close-btn {
  background: transparent;
  border: none;
  color: var(--text-tertiary);
  font-size: 1.2rem;
  cursor: pointer;
  padding: 0.25rem 0.5rem;
  border-radius: var(--radius-sm);
  transition: color var(--transition-fast);
}

.modal-close-btn:hover {
  color: var(--text-primary);
}

.modal-body {
  padding: 1.25rem 1.5rem;
  overflow-y: auto;
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.modal-body h4 {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-top: 1rem;
  margin-bottom: 0.35rem;
}

.modal-body h4:first-child {
  margin-top: 0;
}

.modal-body a {
  color: var(--brand-yt);
  text-decoration: underline;
}

.modal-footer {
  padding: 1rem 1.5rem;
  border-top: 1px solid var(--border-subtle);
  display: flex;
  justify-content: flex-end;
}

.footer-links {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.footer-link {
  color: var(--text-secondary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.footer-link:hover {
  color: var(--brand-yt);
}

/* ==========================================================================
   SEO & Knowledge Sections (How It Works, Features, FAQs)
   ========================================================================== */

.seo-content-wrapper {
  margin-top: 4rem;
  margin-bottom: 3.5rem;
  display: flex;
  flex-direction: column;
  gap: 3.5rem;
}

.seo-block-header {
  margin-bottom: 1.5rem;
}

.seo-block-title {
  font-size: 1.35rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 0.65rem;
  margin-bottom: 0.4rem;
}

.seo-block-subtitle {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.5;
}

.seo-features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.25rem;
}

.seo-steps-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.25rem;
}

@media (max-width: 960px) {
  .seo-features-grid,
  .seo-steps-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 640px) {
  .seo-features-grid,
  .seo-steps-grid {
    grid-template-columns: 1fr;
  }
}

.seo-feature-card,
.seo-step-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  backdrop-filter: var(--glass-blur);
  transition: transform var(--transition-normal), border-color var(--transition-normal), box-shadow var(--transition-normal);
}

.seo-feature-card:hover,
.seo-step-card:hover {
  transform: translateY(-3px);
  border-color: var(--border-medium);
  box-shadow: var(--shadow-md);
}

.seo-feature-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1.1rem;
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-subtle);
}

.seo-step-badge {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.75rem;
  font-weight: 800;
  color: var(--brand-yt);
  background: rgba(255, 0, 51, 0.12);
  border: 1px solid rgba(255, 0, 51, 0.25);
  padding: 0.25rem 0.65rem;
  border-radius: var(--radius-full);
  display: inline-block;
  margin-bottom: 0.85rem;
}

.seo-card-title {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.45rem;
}

.seo-card-text {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.55;
}

/* FAQ Accordion */
.seo-faq-list {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  backdrop-filter: var(--glass-blur);
  transition: all var(--transition-fast);
  overflow: hidden;
}

.faq-item:hover {
  border-color: var(--border-medium);
}

.faq-item[open] {
  border-color: rgba(255, 0, 51, 0.3);
  background: var(--bg-card-hover);
}

.faq-summary {
  padding: 1.15rem 1.35rem;
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-primary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  user-select: none;
  list-style: none;
}

.faq-summary::-webkit-details-marker {
  display: none;
}

.faq-summary::marker {
  content: "";
}

.faq-summary-icon {
  width: 18px;
  height: 18px;
  color: var(--brand-yt);
  transition: transform var(--transition-normal);
  flex-shrink: 0;
  margin-left: 0.75rem;
}

.faq-item[open] .faq-summary-icon {
  transform: rotate(180deg);
}

.faq-answer {
  padding: 0 1.35rem 1.25rem 1.35rem;
  font-size: 0.885rem;
  color: var(--text-secondary);
  line-height: 1.65;
  border-top: 1px solid rgba(255, 255, 255, 0.04);
  padding-top: 0.85rem;
}

.faq-answer strong {
  color: var(--text-primary);
}

/* Responsive adjustments */
@media (max-width: 640px) {
  .hero-section {
    padding: 2rem 0 1.5rem;
  }
  .search-box-glass {
    flex-direction: column;
    padding: 0.75rem;
  }
  .search-input {
    width: 100%;
  }
  .input-tool-actions {
    width: 100%;
    justify-content: flex-end;
    margin-bottom: 0.5rem;
  }
  .btn-primary {
    width: 100%;
    min-height: 44px;
  }
  .tool-btn,
  .preset-chip,
  .study-chip,
  .range-inputs .btn-secondary {
    min-height: 44px;
    display: inline-flex;
    align-items: center;
  }
  .range-inputs {
    width: 100%;
    justify-content: space-between;
    flex-wrap: wrap;
  }
  .range-num-input {
    min-height: 44px;
  }
  .video-checkbox {
    min-width: 22px;
    min-height: 22px;
  }
  .digit-value {
    font-size: 2.2rem;
    min-width: 65px;
    padding: 0.3rem 0.5rem;
  }
  .toast-container {
    left: 1rem;
    right: 1rem;
    bottom: 1rem;
  }
}

/* ==========================================================================
   Reduced Motion Support
   ========================================================================== */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  .ambient-glow,
  .glow-orb-1,
  .glow-orb-2,
  .glow-orb-3 {
    display: none !important;
  }

  .hero-badge,
  .error-card,
  .toast,
  #resultsDashboard,
  .modal-card {
    animation: none !important;
    transform: none !important;
  }
}