/* ============================================================
   NotebookLM Slide Deck Prompts — Design System
   ============================================================ */

/* --- Google Fonts --- */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800;900&family=JetBrains+Mono:wght@400;500;600&display=swap');

/* --- CSS Custom Properties (Design Tokens) --- */
:root {
  /* Colors — Dark Theme (Default) */
  --bg-primary: #0a0a0f;
  --bg-secondary: #12121a;
  --bg-card: rgba(255, 255, 255, 0.04);
  --bg-card-hover: rgba(255, 255, 255, 0.07);
  --bg-glass: rgba(255, 255, 255, 0.06);
  --border-subtle: rgba(255, 255, 255, 0.08);
  --border-card: rgba(255, 255, 255, 0.1);
  --border-glow: rgba(99, 102, 241, 0.3);

  --text-primary: #f0f0f5;
  --text-secondary: #a0a0b8;
  --text-tertiary: #6b6b80;
  --text-inverse: #0a0a0f;

  --accent-primary: #6366f1;
  --accent-secondary: #8b5cf6;
  --accent-gradient: linear-gradient(135deg, #6366f1 0%, #8b5cf6 50%, #a855f7 100%);
  --accent-glow: rgba(99, 102, 241, 0.15);

  --success: #10b981;
  --warning: #f59e0b;
  --danger: #ef4444;

  --tag-basic: #10b981;
  --tag-intermediate: #f59e0b;
  --tag-advanced: #ef4444;

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', monospace;

  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;

  /* Radius */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 30px rgba(99, 102, 241, 0.1);

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 400ms cubic-bezier(0.4, 0, 0.2, 1);

  /* Layout */
  --max-width: 1280px;
  --nav-height: 64px;
}

/* --- Light Theme --- */
[data-theme="light"] {
  --bg-primary: #f8f9fc;
  --bg-secondary: #ffffff;
  --bg-card: rgba(0, 0, 0, 0.02);
  --bg-card-hover: rgba(0, 0, 0, 0.04);
  --bg-glass: rgba(255, 255, 255, 0.7);
  --border-subtle: rgba(0, 0, 0, 0.06);
  --border-card: rgba(0, 0, 0, 0.08);
  --border-glow: rgba(99, 102, 241, 0.2);

  --text-primary: #1a1a2e;
  --text-secondary: #5a5a72;
  --text-tertiary: #9090a8;
  --text-inverse: #f0f0f5;

  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.1);
  --shadow-glow: 0 0 30px rgba(99, 102, 241, 0.05);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--nav-height) + 32px);
}

body {
  font-family: var(--font-sans);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  min-height: 100vh;
  overflow-x: hidden;
}

/* Ambient background glow */
body::before {
  content: '';
  position: fixed;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(ellipse at 30% 20%, rgba(99, 102, 241, 0.06) 0%, transparent 50%),
              radial-gradient(ellipse at 70% 80%, rgba(139, 92, 246, 0.04) 0%, transparent 50%);
  pointer-events: none;
  z-index: -1;
}

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

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

/* --- Navigation --- */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background: var(--bg-glass);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-subtle);
  z-index: 1000;
  display: flex;
  align-items: center;
  padding: 0 var(--space-xl);
}

.nav__inner {
  max-width: var(--max-width);
  width: 100%;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-lg);
}

.nav__brand {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--text-primary);
  white-space: nowrap;
}

.nav__brand-icon {
  font-size: 1.4rem;
}

.nav__controls {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.nav__btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  background: var(--bg-card);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
  font-size: 1.1rem;
}

.nav__btn:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-glow);
  color: var(--text-primary);
}

.nav__lang-btn {
  width: auto;
  padding: 0 var(--space-md);
  font-size: 0.8rem;
  font-weight: 600;
  font-family: var(--font-sans);
  gap: var(--space-xs);
}

/* --- Hero Section --- */
.hero {
  padding: calc(var(--nav-height) + var(--space-3xl)) var(--space-xl) var(--space-2xl);
  text-align: center;
  max-width: var(--max-width);
  margin: 0 auto;
}

.hero__badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-xs) var(--space-md);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-full);
  font-size: 0.8rem;
  color: var(--text-secondary);
  margin-bottom: var(--space-lg);
  background: var(--bg-card);
}

.hero__badge-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--success);
  animation: pulse-dot 2s ease-in-out infinite;
}

@keyframes pulse-dot {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.4; }
}

.hero__title {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 900;
  line-height: 1.15;
  margin-bottom: var(--space-lg);
  letter-spacing: -0.03em;
}

.hero__title-gradient {
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero__subtitle {
  font-size: clamp(1rem, 2vw, 1.25rem);
  color: var(--text-secondary);
  max-width: 640px;
  margin: 0 auto var(--space-2xl);
  line-height: 1.7;
}

/* Search Box */
.search-box {
  max-width: 560px;
  margin: 0 auto;
  position: relative;
}

.search-box__icon {
  position: absolute;
  left: var(--space-lg);
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-tertiary);
  font-size: 1.1rem;
  pointer-events: none;
}

.search-box__input {
  width: 100%;
  padding: var(--space-md) var(--space-lg) var(--space-md) 3rem;
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-lg);
  color: var(--text-primary);
  font-size: 1rem;
  font-family: var(--font-sans);
  outline: none;
  transition: all var(--transition-base);
}

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

.search-box__input:focus {
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px var(--accent-glow), var(--shadow-glow);
}

/* --- Category Navigation (Sticky) --- */
.category-nav {
  position: sticky;
  top: var(--nav-height);
  background: var(--bg-glass);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-subtle);
  z-index: 900;
  padding: var(--space-sm) var(--space-xl);
  overflow-x: auto;
  -ms-overflow-style: none;
  scrollbar-width: none;
}

.category-nav::-webkit-scrollbar {
  display: none;
}

.category-nav__inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.category-nav__btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  padding: var(--space-sm) var(--space-md);
  border: 1px solid transparent;
  border-radius: var(--radius-full);
  background: transparent;
  color: var(--text-secondary);
  font-size: 0.85rem;
  font-weight: 500;
  font-family: var(--font-sans);
  white-space: nowrap;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.category-nav__btn:hover {
  background: var(--bg-card);
  border-color: var(--border-subtle);
  color: var(--text-primary);
}

.category-nav__btn.active {
  background: var(--accent-primary);
  color: #fff;
  border-color: var(--accent-primary);
}

/* Difficulty Filter */
.filter-bar {
  max-width: var(--max-width);
  margin: var(--space-lg) auto 0;
  padding: 0 var(--space-xl);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  flex-wrap: wrap;
}

.filter-bar__btn {
  padding: var(--space-xs) var(--space-md);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-full);
  background: transparent;
  color: var(--text-secondary);
  font-size: 0.8rem;
  font-weight: 500;
  font-family: var(--font-sans);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.filter-bar__btn:hover {
  border-color: var(--border-glow);
  color: var(--text-primary);
}

.filter-bar__btn.active {
  background: var(--bg-card-hover);
  border-color: var(--accent-primary);
  color: var(--accent-primary);
}

/* --- Main Content --- */
.main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--space-xl) var(--space-xl) var(--space-3xl);
}

/* Category Section */
.category-section {
  margin-bottom: var(--space-3xl);
}

.category-section__header {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  margin-bottom: var(--space-xl);
  padding-bottom: var(--space-md);
  border-bottom: 1px solid var(--border-subtle);
}

.category-section__icon {
  font-size: 1.8rem;
}

.category-section__title {
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.category-section__count {
  margin-left: auto;
  font-size: 0.8rem;
  color: var(--text-tertiary);
  padding: var(--space-xs) var(--space-sm);
  background: var(--bg-card);
  border-radius: var(--radius-full);
}

/* Prompt Cards Grid */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(360px, 1fr));
  gap: var(--space-lg);
}

/* Prompt Card */
.prompt-card {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  transition: all var(--transition-base);
  position: relative;
  overflow: hidden;
  opacity: 0;
  transform: translateY(24px);
}

.prompt-card.visible {
  opacity: 1;
  transform: translateY(0);
  transition: opacity 0.5s cubic-bezier(0.4, 0, 0.2, 1),
              transform 0.5s cubic-bezier(0.4, 0, 0.2, 1),
              background var(--transition-base),
              border-color var(--transition-base),
              box-shadow var(--transition-base);
}

.prompt-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--accent-gradient);
  opacity: 0;
  transition: opacity var(--transition-base);
}

.prompt-card:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-glow);
  box-shadow: var(--shadow-glow);
  transform: translateY(-2px);
}

.prompt-card:hover::before {
  opacity: 1;
}

.prompt-card__header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: var(--space-md);
  margin-bottom: var(--space-md);
}

.prompt-card__title {
  font-size: 1.05rem;
  font-weight: 600;
  line-height: 1.4;
  flex: 1;
}

.prompt-card__difficulty {
  flex-shrink: 0;
  padding: 2px var(--space-sm);
  border-radius: var(--radius-full);
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.prompt-card__difficulty--basic {
  background: rgba(16, 185, 129, 0.12);
  color: var(--tag-basic);
}

.prompt-card__difficulty--intermediate {
  background: rgba(245, 158, 11, 0.12);
  color: var(--tag-intermediate);
}

.prompt-card__difficulty--advanced {
  background: rgba(239, 68, 68, 0.12);
  color: var(--tag-advanced);
}

.prompt-card__scenario {
  font-size: 0.88rem;
  color: var(--text-secondary);
  margin-bottom: var(--space-md);
  line-height: 1.6;
}

.prompt-card__label {
  display: block;
  font-size: 0.72rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-tertiary);
  margin-bottom: var(--space-xs);
}

.prompt-card__prompt {
  background: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: var(--space-md);
  margin-bottom: var(--space-md);
  font-family: var(--font-mono);
  font-size: 0.82rem;
  line-height: 1.7;
  color: var(--text-primary);
  white-space: pre-wrap;
  word-break: break-word;
  position: relative;
  max-height: 180px;
  overflow: hidden;
  transition: max-height var(--transition-slow);
}

.prompt-card__prompt.expanded {
  max-height: 2000px;
}

.prompt-card__prompt-fade {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 60px;
  background: linear-gradient(transparent, var(--bg-secondary));
  pointer-events: none;
  transition: opacity var(--transition-fast);
}

.prompt-card__prompt.expanded .prompt-card__prompt-fade {
  opacity: 0;
}

.prompt-card__actions {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  flex-wrap: wrap;
}

.prompt-card__copy-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  padding: var(--space-sm) var(--space-md);
  background: var(--accent-gradient);
  color: #fff;
  border: none;
  border-radius: var(--radius-sm);
  font-size: 0.82rem;
  font-weight: 600;
  font-family: var(--font-sans);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.prompt-card__copy-btn:hover {
  transform: scale(1.03);
  box-shadow: 0 4px 16px rgba(99, 102, 241, 0.3);
}

.prompt-card__copy-btn:active {
  transform: scale(0.97);
}

.prompt-card__expand-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  padding: var(--space-sm) var(--space-md);
  background: transparent;
  color: var(--text-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  font-size: 0.82rem;
  font-weight: 500;
  font-family: var(--font-sans);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.prompt-card__expand-btn:hover {
  border-color: var(--border-glow);
  color: var(--text-primary);
}

.prompt-card__tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs);
  margin-top: var(--space-md);
}

.prompt-card__tag {
  padding: 2px var(--space-sm);
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-full);
  font-size: 0.7rem;
  color: var(--text-tertiary);
}

/* Notes (collapsible) */
.prompt-card__notes {
  margin-top: var(--space-md);
  padding: var(--space-md);
  background: rgba(99, 102, 241, 0.05);
  border-left: 3px solid var(--accent-primary);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.7;
  display: none;
}

.prompt-card__notes.show {
  display: block;
  animation: fade-in 0.3s ease;
}

@keyframes fade-in {
  from { opacity: 0; transform: translateY(-8px); }
  to { opacity: 1; transform: translateY(0); }
}

/* --- Guide Section --- */
.guide {
  max-width: var(--max-width);
  margin: 0 auto var(--space-3xl);
  padding: 0 var(--space-xl);
}

.guide__card {
  background: var(--bg-card);
  border: 1px solid var(--border-card);
  border-radius: var(--radius-xl);
  padding: var(--space-2xl);
  position: relative;
  overflow: hidden;
}

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

.guide__title {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: var(--space-sm);
}

.guide__desc {
  color: var(--text-secondary);
  margin-bottom: var(--space-xl);
}

.guide__steps {
  list-style: none;
  counter-reset: step;
  display: grid;
  gap: var(--space-md);
}

.guide__step {
  counter-increment: step;
  display: flex;
  align-items: flex-start;
  gap: var(--space-md);
  padding: var(--space-md);
  border-radius: var(--radius-md);
  transition: background var(--transition-fast);
}

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

.guide__step::before {
  content: counter(step);
  display: flex;
  align-items: center;
  justify-content: center;
  min-width: 32px;
  height: 32px;
  border-radius: var(--radius-full);
  background: var(--accent-gradient);
  color: #fff;
  font-size: 0.85rem;
  font-weight: 700;
  flex-shrink: 0;
}

/* --- Footer --- */
.footer {
  border-top: 1px solid var(--border-subtle);
  padding: var(--space-2xl) var(--space-xl);
  text-align: center;
}

.footer__inner {
  max-width: var(--max-width);
  margin: 0 auto;
}

.footer__title {
  font-weight: 700;
  font-size: 1rem;
  margin-bottom: var(--space-xs);
}

.footer__sub {
  color: var(--text-tertiary);
  font-size: 0.85rem;
  margin-bottom: var(--space-sm);
}

.footer__copyright {
  color: var(--text-tertiary);
  font-size: 0.75rem;
  margin-bottom: var(--space-md);
  opacity: 0.7;
}

.footer__link {
  font-size: 0.8rem;
  color: var(--text-tertiary);
}

/* --- Toast Notification --- */
.toast {
  position: fixed;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%) translateY(120px);
  padding: var(--space-sm) var(--space-lg);
  background: var(--accent-primary);
  color: #fff;
  border-radius: var(--radius-full);
  font-size: 0.88rem;
  font-weight: 600;
  box-shadow: var(--shadow-lg);
  z-index: 10000;
  pointer-events: none;
  opacity: 0;
  transition: all var(--transition-base);
}

.toast.show {
  transform: translateX(-50%) translateY(0);
  opacity: 1;
}

/* --- No Results --- */
.no-results {
  text-align: center;
  padding: var(--space-3xl) var(--space-xl);
  color: var(--text-tertiary);
  font-size: 1.1rem;
  display: none;
}

.no-results.show {
  display: block;
}

.no-results__icon {
  font-size: 3rem;
  margin-bottom: var(--space-md);
  opacity: 0.4;
}

/* --- Responsive --- */
@media (max-width: 768px) {
  :root {
    --nav-height: 56px;
  }

  .hero {
    padding-top: calc(var(--nav-height) + var(--space-2xl));
  }

  .nav__brand-text {
    display: none;
  }

  .cards-grid {
    grid-template-columns: 1fr;
  }

  .guide__card {
    padding: var(--space-lg);
  }

  .category-section__header {
    flex-wrap: wrap;
  }

  .filter-bar {
    padding: 0 var(--space-md);
  }

  .main {
    padding: var(--space-lg) var(--space-md) var(--space-2xl);
  }
}

@media (min-width: 769px) and (max-width: 1024px) {
  .cards-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}