:root {
  /* Colors - Dark theme */
  --color-bg-primary: #0a0a0f;
  --color-bg-secondary: #12121a;
  --color-bg-card: rgba(24, 24, 35, 0.8);
  --color-bg-card-hover: rgba(30, 30, 45, 0.9);
  --color-border: rgba(255, 255, 255, 0.08);
  --color-border-hover: rgba(255, 255, 255, 0.15);

  /* Text */
  --color-text-primary: #f0f0f5;
  --color-text-secondary: #9999aa;
  --color-text-muted: #666677;

  /* Accent - Vibrant purple/violet gradient */
  --color-accent: #8b5cf6;
  --color-accent-light: #a78bfa;
  --color-accent-dark: #6d28d9;
  --gradient-accent: linear-gradient(135deg, #8b5cf6 0%, #ec4899 100%);
  --gradient-accent-subtle: linear-gradient(135deg, rgba(139, 92, 246, 0.15) 0%, rgba(236, 72, 153, 0.15) 100%);

  /* State colors */
  --color-success: #10b981;
  --color-warning: #f59e0b;
  --color-error: #ef4444;

  /* 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;

  /* Typography */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 2rem;
  --font-size-4xl: 2.5rem;
  --line-height-tight: 1.2;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.7;

  /* Effects */
  --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);
  --shadow-glow: 0 0 30px rgba(139, 92, 246, 0.3);
  --blur-glass: blur(12px);

  /* Borders */
  --radius-sm: 0.375rem;
  --radius-md: 0.75rem;
  --radius-lg: 1rem;
  --radius-xl: 1.5rem;

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 400ms ease;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: var(--line-height-normal);
  color: var(--color-text-primary);
  background: var(--color-bg-primary);
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Background gradient effect */
body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background:
    radial-gradient(ellipse at 20% 0%, rgba(139, 92, 246, 0.15) 0%, transparent 50%),
    radial-gradient(ellipse at 80% 100%, rgba(236, 72, 153, 0.1) 0%, transparent 50%);
  pointer-events: none;
  z-index: -1;
}

/* ===== Layout ===== */
.app {
  max-width: 800px;
  margin: 0 auto;
  padding: var(--space-lg);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  position: relative;
}

/* ===== Header ===== */
.header {
  text-align: center;
  padding: var(--space-3xl) 0 var(--space-2xl);
}

.header-content {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.header-actions {
  position: absolute;
  top: var(--space-lg);
  right: var(--space-lg);
  display: flex;
  gap: var(--space-md);
  align-items: center;
  z-index: 1000;
}

.btn-info {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  color: var(--color-text-secondary);
  border-radius: 50%;
}

.btn-info:hover {
  border-color: var(--color-accent);
  color: var(--color-text-primary);
  transform: translateY(-2px);
}

.github-link {
  color: var(--color-text-secondary);
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: 50%;
  transition: all var(--transition-base);
}

.github-link:hover {
  color: var(--color-text-primary);
  border-color: var(--color-accent);
  transform: translateY(-2px);
}

.logo {
  font-size: var(--font-size-3xl);
  font-weight: 700;
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: var(--space-sm);
  letter-spacing: -0.02em;
}

.tagline {
  color: var(--color-text-secondary);
  font-size: var(--font-size-lg);
}

/* ===== Modal ===== */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.7);
  backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 2000;
  padding: var(--space-md);
  animation: fadeIn 0.3s ease;
}

.modal {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  width: 100%;
  max-width: 700px;
  max-height: 90vh;
  overflow-y: auto;
  box-shadow: var(--shadow-lg);
  padding: var(--space-xl);
  animation: modalSlide 0.4s cubic-bezier(0.16, 1, 0.3, 1);
  position: relative;
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-lg);
  padding-bottom: var(--space-md);
  border-bottom: 1px solid var(--color-border);
}

.btn-close {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--gradient-accent);
  color: white;
  border: none;
  font-size: var(--font-size-2xl);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-base);
}

.btn-close:hover {
  transform: scale(1.1) rotate(90deg);
  box-shadow: var(--shadow-glow);
}

.modal-title {
  font-size: var(--font-size-2xl);
  font-weight: 700;
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.modal-content {
  color: var(--color-text-secondary);
  line-height: var(--line-height-relaxed);
}

.modal-content p {
  margin-bottom: var(--space-lg);
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-md);
  margin-bottom: var(--space-xl);
}

.stat-item {
  background: rgba(255, 255, 255, 0.03);
  padding: var(--space-md);
  border-radius: var(--radius-md);
  text-align: center;
  border: 1px solid var(--color-border);
  transition: all var(--transition-base);
}

.stat-item:hover {
  background: rgba(255, 255, 255, 0.06);
  border-color: var(--color-accent-light);
}

.stat-item--featured {
  grid-column: span 3;
  background: var(--gradient-accent-subtle);
  border-color: rgba(139, 92, 246, 0.2);
}

.stat-item--featured .stat-value {
  font-size: var(--font-size-3xl);
  color: white;
  text-shadow: 0 0 20px rgba(139, 92, 246, 0.5);
}

.stat-value {
  display: block;
  font-size: var(--font-size-xl);
  font-weight: 700;
  color: var(--color-accent-light);
  line-height: 1;
  margin-bottom: var(--space-xs);
}

.stat-label {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.math-explanation {
  font-size: var(--font-size-sm);
  margin-bottom: var(--space-md) !important;
}

.math-formula {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  background: var(--color-bg-secondary);
  padding: var(--space-lg);
  border-radius: var(--radius-lg);
  margin-bottom: var(--space-md);
  font-family: 'Courier New', Courier, monospace;
  font-weight: 700;
  border: 1px dashed var(--color-border);
}

.math-token {
  color: var(--color-accent-light);
  font-size: var(--font-size-lg);
}

.math-op {
  color: var(--color-text-muted);
  font-size: var(--font-size-base);
}

.math-note {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  font-style: italic;
  text-align: center;
}

.info-section h3 {
  color: var(--color-text-primary);
  font-size: var(--font-size-base);
  margin-bottom: var(--space-sm);
}

.info-section ul {
  list-style: none;
}

.info-section li {
  position: relative;
  padding-left: var(--space-lg);
  margin-bottom: var(--space-sm);
  font-size: var(--font-size-sm);
}

.info-section li::before {
  content: '✦';
  position: absolute;
  left: 0;
  color: var(--color-accent);
}

@keyframes fadeIn {
  from {
    opacity: 0;
  }

  to {
    opacity: 1;
  }
}

@keyframes modalSlide {
  from {
    opacity: 0;
    transform: translateY(20px) scale(0.95);
  }

  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

/* ===== Controls ===== */
.controls {
  display: flex;
  gap: var(--space-md);
  margin-bottom: var(--space-lg);
  flex-wrap: wrap;
}

.theme-input-wrapper {
  flex: 1;
  min-width: 200px;
}

.theme-input {
  width: 100%;
  padding: var(--space-md) var(--space-lg);
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  color: var(--color-text-primary);
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  transition: all var(--transition-base);
  backdrop-filter: var(--blur-glass);
}

.theme-input:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(139, 92, 246, 0.2);
}

.theme-input::placeholder {
  color: var(--color-text-muted);
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-xl);
  border: none;
  border-radius: var(--radius-lg);
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-base);
  white-space: nowrap;
}

.btn-primary {
  background: var(--gradient-accent);
  color: white;
  box-shadow: var(--shadow-md), var(--shadow-glow);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg), 0 0 40px rgba(139, 92, 246, 0.4);
}

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

.btn-secondary {
  background: var(--color-bg-card);
  color: var(--color-text-primary);
  border: 1px solid var(--color-border);
  backdrop-filter: var(--blur-glass);
}

.btn-secondary:hover {
  background: var(--color-bg-card-hover);
  border-color: var(--color-border-hover);
}

.btn-icon {
  font-size: var(--font-size-lg);
}

.btn-icon-only {
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: transparent;
  border: 1px solid transparent;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
  font-size: var(--font-size-lg);
}

.btn-icon-only:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: var(--color-border);
}


/* ===== Advanced Controls ===== */
.advanced-controls {
  margin-bottom: var(--space-xl);
}

.advanced-toggle {
  color: var(--color-text-secondary);
  font-size: var(--font-size-sm);
  cursor: pointer;
  padding: var(--space-sm) 0;
  transition: color var(--transition-fast);
  list-style: none;
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.advanced-toggle::-webkit-details-marker {
  display: none;
}

.advanced-toggle::before {
  content: '▸';
  transition: transform var(--transition-fast);
}

details[open] .advanced-toggle::before {
  transform: rotate(90deg);
}

.advanced-toggle:hover {
  color: var(--color-text-primary);
}

.advanced-panel {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-xl);
  align-items: start;
  padding: var(--space-lg);
  margin-top: var(--space-md);
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  backdrop-filter: var(--blur-glass);
}

@media (max-width: 700px) {
  .advanced-panel {
    grid-template-columns: 1fr;
  }
}

.control-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.control-group label {
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
}

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

.slider-label {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  min-width: 50px;
}

.slider-label:last-child {
  text-align: right;
}

input[type="range"] {
  flex: 1;
  height: 6px;
  background: var(--color-bg-secondary);
  border-radius: 3px;
  appearance: none;
  cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
  appearance: none;
  width: 18px;
  height: 18px;
  background: var(--gradient-accent);
  border-radius: 50%;
  cursor: pointer;
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-fast);
}

input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.1);
}

.select-input {
  padding: var(--space-sm) var(--space-md);
  background: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  color: var(--color-text-primary);
  font-family: var(--font-family);
  font-size: var(--font-size-sm);
  cursor: pointer;
  transition: border-color var(--transition-fast);
}

.select-input:focus {
  outline: none;
  border-color: var(--color-accent);
}

/* ===== Output Section ===== */
.output {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
  animation: fadeInUp 0.5s ease;
}

.output.hidden {
  display: none;
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ===== Idea Cards ===== */
.idea-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  backdrop-filter: var(--blur-glass);
  transition: all var(--transition-base);
  animation: cardAppear 0.4s ease backwards;
}

.idea-card:nth-child(1) {
  animation-delay: 0.05s;
}

.idea-card:nth-child(2) {
  animation-delay: 0.1s;
}

.idea-card:nth-child(3) {
  animation-delay: 0.15s;
}

.idea-card:nth-child(4) {
  animation-delay: 0.2s;
}

.idea-card:nth-child(5) {
  animation-delay: 0.25s;
}

.idea-card:nth-child(6) {
  animation-delay: 0.3s;
}

.idea-card:nth-child(7) {
  animation-delay: 0.35s;
}

.idea-card:nth-child(8) {
  animation-delay: 0.4s;
}

@keyframes cardAppear {
  from {
    opacity: 0;
    transform: translateY(10px) scale(0.98);
  }

  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

.idea-card:hover {
  border-color: var(--color-border-hover);
  background: var(--color-bg-card-hover);
}

.idea-card--accent {
  background: var(--gradient-accent-subtle);
  border-color: rgba(139, 92, 246, 0.2);
}

.idea-card--explanation {
  background: rgba(16, 185, 129, 0.08);
  border-color: rgba(16, 185, 129, 0.2);
}


.card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-md);
}

.card-title {
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}


.card-content {
  font-size: var(--font-size-lg);
  line-height: var(--line-height-relaxed);
  color: var(--color-text-primary);
}

.card-content p {
  margin-bottom: var(--space-sm);
}

.card-content p:last-child {
  margin-bottom: 0;
}

.card-content strong {
  color: var(--color-accent-light);
  font-weight: 600;
}

.card-content .tag {
  display: inline-block;
  padding: var(--space-xs) var(--space-sm);
  background: rgba(139, 92, 246, 0.15);
  border-radius: var(--radius-sm);
  font-size: var(--font-size-sm);
  color: var(--color-accent-light);
  margin-right: var(--space-xs);
  margin-bottom: var(--space-xs);
}

/* ===== Export Actions ===== */
.export-actions {
  display: flex;
  gap: var(--space-md);
  justify-content: center;
  margin-top: var(--space-lg);
  padding-top: var(--space-lg);
  border-top: 1px solid var(--color-border);
}

/* ===== Footer ===== */
.footer {
  margin-top: auto;
  padding: var(--space-2xl) 0 var(--space-lg);
  text-align: center;
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
}

/* ===== Utility Classes ===== */
.hidden {
  display: none !important;
}

/* ===== Responsive ===== */
@media (max-width: 600px) {
  .app {
    padding: var(--space-md);
  }

  .header {
    padding: var(--space-2xl) 0 var(--space-xl);
  }

  .logo {
    font-size: var(--font-size-2xl);
  }

  .controls {
    flex-direction: column;
  }

  .btn-primary {
    width: 100%;
  }

  .export-actions {
    flex-direction: column;
  }

  .export-actions .btn {
    width: 100%;
  }
}

/* ===== Toast Notifications ===== */
.toast {
  position: fixed;
  bottom: var(--space-xl);
  left: 50%;
  transform: translateX(-50%) translateY(100px);
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  padding: var(--space-md) var(--space-xl);
  border-radius: var(--radius-lg);
  backdrop-filter: var(--blur-glass);
  box-shadow: var(--shadow-lg);
  opacity: 0;
  transition: all var(--transition-base);
  z-index: 1000;
}

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

.toast.success {
  border-color: var(--color-success);
}