/* ===================================
   DESIGN SYSTEM - TOKENS CSS
   =================================== */

:root {
  /* Colors - Light theme */
  --color-primary: #2563eb;
  --color-primary-hover: #1d4ed8;
  --color-primary-light: #dbeafe;
  --color-secondary: #64748b;
  --color-secondary-hover: #475569;
  --color-accent: #f59e0b;
  --color-accent-hover: #d97706;
  
  /* Semantic colors */
  --color-success: #10b981;
  --color-success-light: #d1fae5;
  --color-warning: #f59e0b;
  --color-warning-light: #fef3c7;
  --color-error: #ef4444;
  --color-error-light: #fee2e2;
  --color-info: #3b82f6;
  --color-info-light: #dbeafe;
  
  /* Neutral colors */
  --color-white: #ffffff;
  --color-gray-50: #f9fafb;
  --color-gray-100: #f3f4f6;
  --color-gray-200: #e5e7eb;
  --color-gray-300: #d1d5db;
  --color-gray-400: #9ca3af;
  --color-gray-500: #6b7280;
  --color-gray-600: #4b5563;
  --color-gray-700: #374151;
  --color-gray-800: #1f2937;
  --color-gray-900: #111827;
  
  /* Text colors */
  --color-text-primary: #111827;
  --color-text-secondary: #4b5563;
  --color-text-tertiary: #6b7280;
  --color-text-inverse: #ffffff;
  
  /* Background colors */
  --color-bg-primary: #ffffff;
  --color-bg-secondary: #f9fafb;
  --color-bg-tertiary: #f3f4f6;
  --color-bg-inverse: #111827;
  
  /* Border colors */
  --color-border: #e5e7eb;
  --color-border-hover: #d1d5db;
  --color-border-focus: var(--color-primary);
  
  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
  --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
  
  /* Typography */
  --font-family-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-family-mono: "SF Mono", Monaco, Inconsolata, "Roboto Mono", monospace;
  
  /* Font sizes */
  --font-size-xs: 0.75rem;    /* 12px */
  --font-size-sm: 0.875rem;   /* 14px */
  --font-size-base: 1rem;     /* 16px */
  --font-size-lg: 1.125rem;   /* 18px */
  --font-size-xl: 1.25rem;    /* 20px */
  --font-size-2xl: 1.5rem;    /* 24px */
  --font-size-3xl: 1.875rem;  /* 30px */
  --font-size-4xl: 2.25rem;   /* 36px */
  --font-size-5xl: 3rem;      /* 48px */
  --font-size-6xl: 3.75rem;   /* 60px */
  
  /* Line heights */
  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.75;
  
  /* Font weights */
  --font-weight-light: 300;
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  --font-weight-extrabold: 800;
  
  /* Spacing */
  --space-1: 0.25rem;   /* 4px */
  --space-2: 0.5rem;    /* 8px */
  --space-3: 0.75rem;   /* 12px */
  --space-4: 1rem;      /* 16px */
  --space-5: 1.25rem;   /* 20px */
  --space-6: 1.5rem;    /* 24px */
  --space-8: 2rem;      /* 32px */
  --space-10: 2.5rem;   /* 40px */
  --space-12: 3rem;     /* 48px */
  --space-16: 4rem;     /* 64px */
  --space-20: 5rem;     /* 80px */
  --space-24: 6rem;     /* 96px */
  --space-32: 8rem;     /* 128px */
  
  /* Border radius */
  --radius-sm: 0.125rem;  /* 2px */
  --radius-md: 0.375rem;  /* 6px */
  --radius-lg: 0.5rem;    /* 8px */
  --radius-xl: 0.75rem;   /* 12px */
  --radius-2xl: 1rem;     /* 16px */
  --radius-3xl: 1.5rem;   /* 24px */
  --radius-full: 9999px;
  
  /* Transitions */
  --transition-fast: 150ms ease-in-out;
  --transition-normal: 250ms ease-in-out;
  --transition-slow: 350ms ease-in-out;
  
  /* Z-index */
  --z-dropdown: 1000;
  --z-sticky: 1020;
  --z-fixed: 1030;
  --z-modal-backdrop: 1040;
  --z-modal: 1050;
  --z-popover: 1060;
  --z-tooltip: 1070;
  --z-toast: 1080;
}

/* Dark theme */
@media (prefers-color-scheme: dark) {
  :root {
    --color-primary: #3b82f6;
    --color-primary-hover: #2563eb;
    --color-primary-light: #1e3a8a;
    --color-secondary: #94a3b8;
    --color-secondary-hover: #64748b;
    --color-accent: #f59e0b;
    --color-accent-hover: #d97706;
    
    --color-success: #10b981;
    --color-success-light: #064e3b;
    --color-warning: #f59e0b;
    --color-warning-light: #78350f;
    --color-error: #ef4444;
    --color-error-light: #7f1d1d;
    --color-info: #3b82f6;
    --color-info-light: #1e3a8a;
    
    --color-white: #ffffff;
    --color-gray-50: #f9fafb;
    --color-gray-100: #f3f4f6;
    --color-gray-200: #e5e7eb;
    --color-gray-300: #d1d5db;
    --color-gray-400: #9ca3af;
    --color-gray-500: #6b7280;
    --color-gray-600: #4b5563;
    --color-gray-700: #374151;
    --color-gray-800: #1f2937;
    --color-gray-900: #111827;
    
    --color-text-primary: #f9fafb;
    --color-text-secondary: #d1d5db;
    --color-text-tertiary: #9ca3af;
    --color-text-inverse: #111827;
    
    --color-bg-primary: #111827;
    --color-bg-secondary: #1f2937;
    --color-bg-tertiary: #374151;
    --color-bg-inverse: #ffffff;
    
    --color-border: #374151;
    --color-border-hover: #4b5563;
    --color-border-focus: var(--color-primary);
  }
}

/* Manual dark mode class */
body.dark-mode {
  --color-primary: #3b82f6;
  --color-primary-hover: #2563eb;
  --color-primary-light: #1e3a8a;
  --color-secondary: #94a3b8;
  --color-secondary-hover: #64748b;
  --color-accent: #f59e0b;
  --color-accent-hover: #d97706;
  
  --color-success: #10b981;
  --color-success-light: #064e3b;
  --color-warning: #f59e0b;
  --color-warning-light: #78350f;
  --color-error: #ef4444;
  --color-error-light: #7f1d1d;
  --color-info: #3b82f6;
  --color-info-light: #1e3a8a;
  
  --color-text-primary: #f9fafb;
  --color-text-secondary: #d1d5db;
  --color-text-tertiary: #9ca3af;
  --color-text-inverse: #111827;
  
  --color-bg-primary: #111827;
  --color-bg-secondary: #1f2937;
  --color-bg-tertiary: #374151;
  --color-bg-inverse: #ffffff;
  
  --color-border: #374151;
  --color-border-hover: #4b5563;
  --color-border-focus: var(--color-primary);
}

/* ===================================
   BASE STYLES & RESET
   =================================== */

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

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

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

img {
  max-width: 100%;
  height: auto;
  display: block;
}

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

a:hover {
  color: var(--color-primary-hover);
  text-decoration: underline;
}

a:focus-visible {
  outline: 2px solid var(--color-border-focus);
  outline-offset: 2px;
  border-radius: var(--radius-md);
}

/* Skip link for accessibility */
.skip-link {
  position: absolute;
  top: -40px;
  left: 6px;
  background: var(--color-primary);
  color: var(--color-white);
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-md);
  text-decoration: none;
  z-index: var(--z-tooltip);
  transition: top var(--transition-fast);
}

.skip-link:focus {
  top: 6px;
}

/* ===================================
   LAYOUT COMPONENTS
   =================================== */

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-4);
}

@media (min-width: 640px) {
  .container {
    padding: 0 var(--space-6);
  }
}

@media (min-width: 1024px) {
  .container {
    padding: 0 var(--space-8);
  }
}

/* Header */
.header {
  background-color: var(--color-bg-primary);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  backdrop-filter: blur(8px);
  background-color: rgba(var(--color-bg-primary), 0.8);
}

.header-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 4rem;
  gap: var(--space-4);
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-weight: var(--font-weight-bold);
  font-size: var(--font-size-xl);
  color: var(--color-text-primary);
}

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

.nav-list {
  display: flex;
  list-style: none;
  gap: var(--space-6);
}

.nav-link {
  color: var(--color-text-secondary);
  font-weight: var(--font-weight-medium);
  padding: var(--space-2) 0;
  border-bottom: 2px solid transparent;
  transition: all var(--transition-fast);
}

.nav-link:hover,
.nav-link:focus {
  color: var(--color-primary);
  text-decoration: none;
  border-bottom-color: var(--color-primary);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

/* Main content */
.main {
  min-height: calc(100vh - 4rem);
}

/* Sections */
.section {
  padding: var(--space-16) 0;
}

.section-alt {
  background-color: var(--color-bg-secondary);
}

.section-header {
  text-align: center;
  margin-bottom: var(--space-12);
  max-width: 800px;
  margin-left: auto;
  margin-right: auto;
}

.section-title {
  font-size: var(--font-size-4xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-primary);
  margin-bottom: var(--space-4);
  line-height: var(--line-height-tight);
}

.section-subtitle {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  line-height: var(--line-height-relaxed);
}

/* Footer */
.footer {
  background-color: var(--color-bg-secondary);
  border-top: 1px solid var(--color-border);
  padding: var(--space-16) 0 var(--space-8);
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--space-8);
  margin-bottom: var(--space-8);
}

.footer-section h3 {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--space-4);
  color: var(--color-text-primary);
}

.footer-links {
  list-style: none;
}

.footer-links li {
  margin-bottom: var(--space-2);
}

.footer-links a {
  color: var(--color-text-secondary);
  font-size: var(--font-size-sm);
}

.footer-links a:hover {
  color: var(--color-primary);
}

.footer-bottom {
  border-top: 1px solid var(--color-border);
  padding-top: var(--space-8);
  text-align: center;
  color: var(--color-text-tertiary);
  font-size: var(--font-size-sm);
}

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

.hero {
  position: relative;
  min-height: 600px;
  display: flex;
  align-items: center;
  overflow: hidden;
}

.hero-background {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: -1;
}

.hero-svg {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.hero-content {
  text-align: center;
  color: var(--color-text-inverse);
  max-width: 800px;
  margin: 0 auto;
  z-index: 1;
}

.hero-title {
  font-size: var(--font-size-6xl);
  font-weight: var(--font-weight-extrabold);
  margin-bottom: var(--space-6);
  line-height: var(--line-height-tight);
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
}

.hero-subtitle {
  font-size: var(--font-size-xl);
  margin-bottom: var(--space-8);
  line-height: var(--line-height-relaxed);
  opacity: 0.9;
}

.hero-actions {
  display: flex;
  gap: var(--space-4);
  justify-content: center;
  flex-wrap: wrap;
}

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

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-6);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-medium);
  line-height: 1;
  border: 1px solid transparent;
  border-radius: var(--radius-lg);
  cursor: pointer;
  text-decoration: none;
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.btn:focus-visible {
  outline: 2px solid var(--color-border-focus);
  outline-offset: 2px;
}

.btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

/* Button variants */
.btn-primary {
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
  border-color: var(--color-primary);
}

.btn-primary:hover:not(:disabled) {
  background-color: var(--color-primary-hover);
  border-color: var(--color-primary-hover);
  color: var(--color-text-inverse);
  text-decoration: none;
}

.btn-secondary {
  background-color: var(--color-secondary);
  color: var(--color-text-inverse);
  border-color: var(--color-secondary);
}

.btn-secondary:hover:not(:disabled) {
  background-color: var(--color-secondary-hover);
  border-color: var(--color-secondary-hover);
  color: var(--color-text-inverse);
  text-decoration: none;
}

.btn-outline {
  background-color: transparent;
  color: var(--color-primary);
  border-color: var(--color-primary);
}

.btn-outline:hover:not(:disabled) {
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
  text-decoration: none;
}

.btn-ghost {
  background-color: transparent;
  color: var(--color-text-secondary);
  border-color: transparent;
}

.btn-ghost:hover:not(:disabled) {
  background-color: var(--color-bg-tertiary);
  color: var(--color-text-primary);
  text-decoration: none;
}

.btn-icon {
  padding: var(--space-2);
  aspect-ratio: 1;
}

.btn-sm {
  padding: var(--space-2) var(--space-4);
  font-size: var(--font-size-sm);
}

.btn-lg {
  padding: var(--space-4) var(--space-8);
  font-size: var(--font-size-lg);
}

/* ===================================
   FORM ELEMENTS
   =================================== */

.form-group {
  margin-bottom: var(--space-4);
}

.form-label {
  display: block;
  margin-bottom: var(--space-2);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-primary);
}

.form-input,
.form-select,
.form-textarea {
  width: 100%;
  padding: var(--space-3);
  font-size: var(--font-size-base);
  line-height: var(--line-height-normal);
  color: var(--color-text-primary);
  background-color: var(--color-bg-primary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
  outline: none;
  border-color: var(--color-border-focus);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-input:disabled,
.form-select:disabled,
.form-textarea:disabled {
  background-color: var(--color-bg-tertiary);
  opacity: 0.6;
  cursor: not-allowed;
}

.form-textarea {
  resize: vertical;
  min-height: 100px;
}

/* Search box */
.search-box {
  position: relative;
  max-width: 400px;
  margin-bottom: var(--space-6);
}

.search-input {
  width: 100%;
  padding: var(--space-3) var(--space-10) var(--space-3) var(--space-4);
  font-size: var(--font-size-base);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  background-color: var(--color-bg-primary);
  color: var(--color-text-primary);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.search-input:focus {
  outline: none;
  border-color: var(--color-border-focus);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.search-btn {
  position: absolute;
  right: var(--space-2);
  top: 50%;
  transform: translateY(-50%);
  background: none;
  border: none;
  padding: var(--space-2);
  cursor: pointer;
  color: var(--color-text-tertiary);
  border-radius: var(--radius-full);
  transition: color var(--transition-fast), background-color var(--transition-fast);
}

.search-btn:hover {
  color: var(--color-primary);
  background-color: var(--color-bg-tertiary);
}

/* Filters */
.filters {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
  margin-bottom: var(--space-6);
}

.filter-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  min-width: 150px;
}

.filter-label {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-secondary);
}

.filter-select {
  padding: var(--space-2) var(--space-3);
  font-size: var(--font-size-sm);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  background-color: var(--color-bg-primary);
  color: var(--color-text-primary);
  cursor: pointer;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.filter-select:focus {
  outline: none;
  border-color: var(--color-border-focus);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

/* Active filters */
.active-filters {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-bottom: var(--space-6);
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-1) var(--space-3);
  font-size: var(--font-size-sm);
  background-color: var(--color-primary-light);
  color: var(--color-primary);
  border-radius: var(--radius-full);
  border: 1px solid var(--color-primary);
}

.chip-remove {
  background: none;
  border: none;
  cursor: pointer;
  color: var(--color-primary);
  font-size: var(--font-size-lg);
  line-height: 1;
  padding: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  transition: background-color var(--transition-fast);
}

.chip-remove:hover {
  background-color: rgba(0, 0, 0, 0.1);
}

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

.card {
  background-color: var(--color-bg-primary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
  transition: box-shadow var(--transition-fast), transform var(--transition-fast);
}

.card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.card-header {
  padding: var(--space-6);
  border-bottom: 1px solid var(--color-border);
}

.card-title {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
  margin-bottom: var(--space-2);
}

.card-subtitle {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
}

.card-body {
  padding: var(--space-6);
}

.card-footer {
  padding: var(--space-6);
  border-top: 1px solid var(--color-border);
  background-color: var(--color-bg-secondary);
}

/* Dinosaurs grid */
.dinosaurs-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: var(--space-6);
  margin-bottom: var(--space-8);
}

.dinosaur-card {
  cursor: pointer;
  transition: all var(--transition-fast);
}

.dinosaur-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.dinosaur-image {
  height: 200px;
  background: linear-gradient(135deg, var(--color-gray-200), var(--color-gray-300));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--font-size-6xl);
  color: var(--color-text-tertiary);
}

.dinosaur-name {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
  margin-bottom: var(--space-2);
}

.dinosaur-meta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-bottom: var(--space-4);
}

.dinosaur-tag {
  padding: var(--space-1) var(--space-2);
  font-size: var(--font-size-xs);
  background-color: var(--color-bg-tertiary);
  color: var(--color-text-secondary);
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
}

.dinosaur-stats {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-3);
}

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

.dinosaur-stat-value {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  color: var(--color-primary);
}

.dinosaur-stat-label {
  font-size: var(--font-size-xs);
  color: var(--color-text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* Results header */
.results-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-6);
  flex-wrap: wrap;
  gap: var(--space-4);
}

.results-count {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
}

.results-actions {
  display: flex;
  gap: var(--space-2);
}

/* ===================================
   TIMELINE
   =================================== */

.timeline-container {
  background-color: var(--color-bg-primary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
  box-shadow: var(--shadow-sm);
}

.timeline-controls {
  display: flex;
  gap: var(--space-2);
  margin-bottom: var(--space-4);
  justify-content: center;
}

.timeline-viewport {
  width: 100%;
  overflow: hidden;
  border-radius: var(--radius-lg);
  margin-bottom: var(--space-4);
}

.timeline-svg {
  width: 100%;
  height: 400px;
  background-color: var(--color-bg-secondary);
  border-radius: var(--radius-lg);
}

.timeline-legend {
  display: flex;
  justify-content: center;
  gap: var(--space-6);
  flex-wrap: wrap;
}

.legend-item {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
}

.legend-color {
  width: 16px;
  height: 16px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border);
}

/* ===================================
   CALCULATIONS SECTION
   =================================== */

.calculations-container {
  background-color: var(--color-bg-primary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.calc-tabs {
  display: flex;
  border-bottom: 1px solid var(--color-border);
  background-color: var(--color-bg-secondary);
  overflow-x: auto;
}

.calc-tab {
  padding: var(--space-4) var(--space-6);
  background: none;
  border: none;
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-secondary);
  cursor: pointer;
  border-bottom: 3px solid transparent;
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.calc-tab:hover {
  color: var(--color-text-primary);
  background-color: var(--color-bg-tertiary);
}

.calc-tab.active {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
  background-color: var(--color-bg-primary);
}

.calc-panels {
  padding: var(--space-6);
}

.calc-panel {
  display: none;
}

.calc-panel.active {
  display: block;
}

.calc-content h3 {
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
  margin-bottom: var(--space-6);
}

.calc-formula {
  background-color: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-4);
  margin-bottom: var(--space-6);
  font-family: var(--font-family-mono);
  font-size: var(--font-size-sm);
}

.calc-constants {
  margin-bottom: var(--space-6);
}

.calc-constants h4 {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
  margin-bottom: var(--space-3);
}

.constant-item {
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: var(--space-4);
  padding: var(--space-2) 0;
  border-bottom: 1px solid var(--color-border);
}

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

.constant-name {
  font-weight: var(--font-weight-medium);
  color: var(--color-text-secondary);
}

.constant-value {
  font-family: var(--font-family-mono);
  color: var(--color-primary);
}

.constant-ref {
  font-size: var(--font-size-xs);
  color: var(--color-text-tertiary);
  font-style: italic;
}

.calc-demo {
  background-color: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-4);
  margin-bottom: var(--space-6);
}

.calc-demo h4 {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
  margin-bottom: var(--space-4);
}

.demo-inputs {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  margin-bottom: var(--space-4);
}

.demo-inputs label {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-secondary);
}

.demo-inputs input[type="number"] {
  padding: var(--space-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  font-size: var(--font-size-sm);
}

.metabolism-toggle,
.gait-toggle {
  display: flex;
  gap: var(--space-4);
}

.metabolism-toggle label,
.gait-toggle label {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--font-size-sm);
  cursor: pointer;
}

.calc-result {
  padding: var(--space-3);
  background-color: var(--color-info-light);
  border: 1px solid var(--color-info);
  border-radius: var(--radius-md);
  color: var(--color-info);
  font-family: var(--font-family-mono);
  font-size: var(--font-size-sm);
}

.calc-explanation {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  line-height: var(--line-height-relaxed);
}

.calc-explanation h4 {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
  margin-bottom: var(--space-3);
}

/* ===================================
   COMPARISON SECTION
   =================================== */

.comparison-container {
  background-color: var(--color-bg-primary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
  box-shadow: var(--shadow-sm);
}

.comparison-selector h3 {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
  margin-bottom: var(--space-4);
}

.comparison-options {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: var(--space-3);
  margin-bottom: var(--space-6);
}

.comparison-option {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.comparison-option:hover {
  background-color: var(--color-bg-secondary);
}

.comparison-option input[type="checkbox"] {
  cursor: pointer;
}

.comparison-option label {
  cursor: pointer;
  font-size: var(--font-size-sm);
  color: var(--color-text-primary);
}

.comparison-results {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-6);
}

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

.comparison-chart {
  background-color: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-4);
  display: flex;
  justify-content: center;
  align-items: center;
}

.comparison-table {
  background-color: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-4);
  overflow-x: auto;
}

/* ===================================
   DOCUMENTATION SECTION
   =================================== */

.docs-container {
  background-color: var(--color-bg-primary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.docs-nav {
  display: flex;
  border-bottom: 1px solid var(--color-border);
  background-color: var(--color-bg-secondary);
  overflow-x: auto;
}

.docs-tab {
  padding: var(--space-4) var(--space-6);
  background: none;
  border: none;
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-secondary);
  cursor: pointer;
  border-bottom: 3px solid transparent;
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.docs-tab:hover {
  color: var(--color-text-primary);
  background-color: var(--color-bg-tertiary);
}

.docs-tab.active {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
  background-color: var(--color-bg-primary);
}

.docs-content {
  padding: var(--space-6);
}

.docs-viewer {
  min-height: 400px;
  margin-bottom: var(--space-6);
}

.docs-actions {
  display: flex;
  justify-content: flex-end;
}

/* Markdown content styling */
.markdown h1,
.markdown h2,
.markdown h3,
.markdown h4,
.markdown h5,
.markdown h6 {
  margin-top: var(--space-6);
  margin-bottom: var(--space-4);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
}

.markdown h1 {
  font-size: var(--font-size-3xl);
}

.markdown h2 {
  font-size: var(--font-size-2xl);
}

.markdown h3 {
  font-size: var(--font-size-xl);
}

.markdown h4 {
  font-size: var(--font-size-lg);
}

.markdown p {
  margin-bottom: var(--space-4);
  line-height: var(--line-height-relaxed);
  color: var(--color-text-secondary);
}

.markdown ul,
.markdown ol {
  margin-bottom: var(--space-4);
  padding-left: var(--space-6);
  color: var(--color-text-secondary);
}

.markdown li {
  margin-bottom: var(--space-2);
}

.markdown code {
  background-color: var(--color-bg-tertiary);
  padding: var(--space-1) var(--space-2);
  border-radius: var(--radius-sm);
  font-family: var(--font-family-mono);
  font-size: var(--font-size-sm);
  color: var(--color-primary);
}

.markdown pre {
  background-color: var(--color-bg-tertiary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-4);
  overflow-x: auto;
  margin-bottom: var(--space-4);
}

.markdown pre code {
  background: none;
  padding: 0;
}

.markdown blockquote {
  border-left: 4px solid var(--color-primary);
  padding-left: var(--space-4);
  margin: var(--space-4) 0;
  color: var(--color-text-secondary);
  font-style: italic;
}

.markdown table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: var(--space-4);
}

.markdown th,
.markdown td {
  padding: var(--space-2) var(--space-3);
  text-align: left;
  border-bottom: 1px solid var(--color-border);
}

.markdown th {
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
}

.markdown a {
  color: var(--color-primary);
  text-decoration: none;
}

.markdown a:hover {
  text-decoration: underline;
}

/* ===================================
   TESTS SECTION
   =================================== */

.tests-container {
  background-color: var(--color-bg-primary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
  box-shadow: var(--shadow-sm);
}

.tests-controls {
  display: flex;
  gap: var(--space-3);
  margin-bottom: var(--space-6);
  justify-content: center;
}

.tests-results {
  background-color: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
}

.tests-summary h3 {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
  margin-bottom: var(--space-4);
}

.test-stats {
  display: flex;
  gap: var(--space-6);
  margin-bottom: var(--space-6);
  flex-wrap: wrap;
}

.stat-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: var(--space-3);
  background-color: var(--color-bg-primary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  min-width: 100px;
}

.stat-label {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-1);
}

.stat-value {
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-bold);
}

.stat-value.success {
  color: var(--color-success);
}

.stat-value.error {
  color: var(--color-error);
}

.test-details {
  background-color: var(--color-bg-primary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-4);
  max-height: 400px;
  overflow-y: auto;
}

.test-item {
  padding: var(--space-3);
  border-bottom: 1px solid var(--color-border);
}

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

.test-item.success {
  border-left: 4px solid var(--color-success);
}

.test-item.error {
  border-left: 4px solid var(--color-error);
}

.test-name {
  font-weight: var(--font-weight-medium);
  color: var(--color-text-primary);
  margin-bottom: var(--space-1);
}

.test-message {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  font-family: var(--font-family-mono);
}

/* ===================================
   MODAL
   =================================== */

.modal {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: var(--z-modal);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-normal), visibility var(--transition-normal);
}

.modal.active {
  opacity: 1;
  visibility: visible;
}

.modal-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(4px);
}

.modal-content {
  position: relative;
  background-color: var(--color-bg-primary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-2xl);
  max-width: 800px;
  max-height: 90vh;
  width: 90%;
  overflow: hidden;
  transform: scale(0.9);
  transition: transform var(--transition-normal);
}

.modal.active .modal-content {
  transform: scale(1);
}

.modal-header {
  padding: var(--space-6);
  border-bottom: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.modal-title {
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
}

.modal-close {
  background: none;
  border: none;
  font-size: var(--font-size-2xl);
  cursor: pointer;
  color: var(--color-text-tertiary);
  padding: var(--space-2);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
  line-height: 1;
}

.modal-close:hover {
  color: var(--color-text-primary);
  background-color: var(--color-bg-tertiary);
}

.modal-body {
  padding: var(--space-6);
  max-height: calc(90vh - 140px);
  overflow-y: auto;
}

.modal-footer {
  padding: var(--space-6);
  border-top: 1px solid var(--color-border);
  background-color: var(--color-bg-secondary);
  display: flex;
  justify-content: flex-end;
  gap: var(--space-3);
}

/* ===================================
   TOAST NOTIFICATIONS
   =================================== */

.toast-container {
  position: fixed;
  top: var(--space-4);
  right: var(--space-4);
  z-index: var(--z-toast);
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.toast {
  background-color: var(--color-bg-primary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  padding: var(--space-4);
  min-width: 300px;
  max-width: 500px;
  transform: translateX(100%);
  transition: transform var(--transition-normal);
}

.toast.show {
  transform: translateX(0);
}

.toast.success {
  border-left: 4px solid var(--color-success);
}

.toast.error {
  border-left: 4px solid var(--color-error);
}

.toast.warning {
  border-left: 4px solid var(--color-warning);
}

.toast.info {
  border-left: 4px solid var(--color-info);
}

.toast-title {
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
  margin-bottom: var(--space-1);
}

.toast-message {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
}

/* ===================================
   LOADING & EMPTY STATES
   =================================== */

.loading {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--space-16);
  color: var(--color-text-secondary);
}

.loading-spinner {
  width: 40px;
  height: 40px;
  border: 4px solid var(--color-border);
  border-top: 4px solid var(--color-primary);
  border-radius: 50%;
  animation: spin 1s linear infinite;
  margin-bottom: var(--space-4);
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

.no-results {
  text-align: center;
  padding: var(--space-16);
  color: var(--color-text-secondary);
}

.no-results h3 {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-primary);
  margin-bottom: var(--space-4);
}

/* ===================================
   ACCESSIBILITY & REDUCED MOTION
   =================================== */

@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;
  }
}

/* Focus visible for better keyboard navigation */
:focus-visible {
  outline: 2px solid var(--color-border-focus);
  outline-offset: 2px;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
  :root {
    --color-border: #000000;
    --color-text-primary: #000000;
    --color-bg-primary: #ffffff;
  }
  
  body.dark-mode {
    --color-border: #ffffff;
    --color-text-primary: #ffffff;
    --color-bg-primary: #000000;
  }
}

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

@media (max-width: 768px) {
  .header-content {
    flex-direction: column;
    height: auto;
    padding: var(--space-4) 0;
  }
  
  .nav-list {
    gap: var(--space-4);
  }
  
  .hero-title {
    font-size: var(--font-size-4xl);
  }
  
  .hero-subtitle {
    font-size: var(--font-size-lg);
  }
  
  .section-title {
    font-size: var(--font-size-3xl);
  }
  
  .dinosaurs-grid {
    grid-template-columns: 1fr;
  }
  
  .filters {
    flex-direction: column;
  }
  
  .filter-group {
    min-width: 100%;
  }
  
  .results-header {
    flex-direction: column;
    align-items: flex-start;
  }
  
  .calc-tabs,
  .docs-nav {
    flex-wrap: nowrap;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
  }
  
  .comparison-results {
    grid-template-columns: 1fr;
  }
  
  .toast-container {
    left: var(--space-4);
    right: var(--space-4);
  }
  
  .toast {
    min-width: auto;
    width: 100%;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 var(--space-4);
  }
  
  .hero {
    min-height: 500px;
  }
  
  .hero-title {
    font-size: var(--font-size-3xl);
  }
  
  .section {
    padding: var(--space-12) 0;
  }
  
  .modal-content {
    width: 95%;
  }
}

/* ===================================
   PRINT STYLES
   =================================== */

@media print {
  .header,
  .footer,
  .nav,
  .filters,
  .results-actions,
  .timeline-controls,
  .calc-tabs,
  .docs-nav,
  .tests-controls,
  .modal,
  .toast-container {
    display: none !important;
  }
  
  .section {
    break-inside: avoid;
    page-break-inside: avoid;
  }
  
  .dinosaur-card {
    break-inside: avoid;
    page-break-inside: avoid;
  }
  
  body {
    font-size: 12pt;
    line-height: 1.4;
  }
  
  .section-title {
    font-size: 18pt;
  }
  
  .hero {
    min-height: auto;
    padding: var(--space-4) 0;
  }
  
  .hero-background {
    display: none;
  }
  
  .hero-content {
    color: var(--color-text-primary);
  }
}