/* ==========================================================================
   Design System - Dinosaures Science
   ========================================================================== */

/* CSS Custom Properties (Design Tokens) */
:root {
    /* Colors - Light Mode */
    --color-primary: hsl(210, 100%, 50%);
    --color-primary-dark: hsl(210, 100%, 40%);
    --color-primary-light: hsl(210, 100%, 95%);
    
    --color-secondary: hsl(150, 60%, 50%);
    --color-secondary-dark: hsl(150, 60%, 40%);
    --color-secondary-light: hsl(150, 60%, 95%);
    
    --color-accent: hsl(280, 70%, 60%);
    --color-accent-dark: hsl(280, 70%, 50%);
    --color-accent-light: hsl(280, 70%, 95%);
    
    --color-success: hsl(140, 70%, 45%);
    --color-warning: hsl(45, 100%, 55%);
    --color-error: hsl(0, 80%, 55%);
    
    --color-neutral-50: hsl(210, 20%, 98%);
    --color-neutral-100: hsl(210, 20%, 95%);
    --color-neutral-200: hsl(210, 20%, 90%);
    --color-neutral-300: hsl(210, 20%, 80%);
    --color-neutral-400: hsl(210, 20%, 65%);
    --color-neutral-500: hsl(210, 20%, 50%);
    --color-neutral-600: hsl(210, 20%, 35%);
    --color-neutral-700: hsl(210, 20%, 25%);
    --color-neutral-800: hsl(210, 20%, 15%);
    --color-neutral-900: hsl(210, 20%, 10%);
    
    /* Semantic Colors */
    --color-background: var(--color-neutral-50);
    --color-surface: white;
    --color-surface-elevated: white;
    --color-border: var(--color-neutral-200);
    --color-border-strong: var(--color-neutral-300);
    --color-text-primary: var(--color-neutral-900);
    --color-text-secondary: var(--color-neutral-600);
    --color-text-tertiary: var(--color-neutral-500);
    --color-text-inverse: white;
    
    /* Typography */
    --font-family-primary: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    --font-family-mono: 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', Consolas, 'Courier New', monospace;
    
    --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 */
    
    --font-weight-normal: 400;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;
    
    --line-height-tight: 1.25;
    --line-height-normal: 1.5;
    --line-height-relaxed: 1.75;
    
    /* Spacing */
    --spacing-1: 0.25rem;   /* 4px */
    --spacing-2: 0.5rem;    /* 8px */
    --spacing-3: 0.75rem;   /* 12px */
    --spacing-4: 1rem;      /* 16px */
    --spacing-5: 1.25rem;   /* 20px */
    --spacing-6: 1.5rem;    /* 24px */
    --spacing-8: 2rem;      /* 32px */
    --spacing-10: 2.5rem;   /* 40px */
    --spacing-12: 3rem;     /* 48px */
    --spacing-16: 4rem;     /* 64px */
    --spacing-20: 5rem;     /* 80px */
    --spacing-24: 6rem;     /* 96px */
    --spacing-32: 8rem;     /* 128px */
    
    /* Border Radius */
    --radius-sm: 0.25rem;   /* 4px */
    --radius-base: 0.375rem; /* 6px */
    --radius-md: 0.5rem;    /* 8px */
    --radius-lg: 0.75rem;   /* 12px */
    --radius-xl: 1rem;      /* 16px */
    --radius-2xl: 1.5rem;   /* 24px */
    --radius-full: 9999px;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-base: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    --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);
    
    /* Transitions */
    --transition-fast: 150ms ease-in-out;
    --transition-base: 250ms ease-in-out;
    --transition-slow: 350ms ease-in-out;
    
    /* Z-index Scale */
    --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 Mode */
[data-theme="dark"] {
    --color-background: var(--color-neutral-900);
    --color-surface: var(--color-neutral-800);
    --color-surface-elevated: var(--color-neutral-700);
    --color-border: var(--color-neutral-700);
    --color-border-strong: var(--color-neutral-600);
    --color-text-primary: var(--color-neutral-100);
    --color-text-secondary: var(--color-neutral-300);
    --color-text-tertiary: var(--color-neutral-400);
    
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
    --shadow-base: 0 1px 3px 0 rgba(0, 0, 0, 0.4), 0 1px 2px 0 rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -1px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -2px rgba(0, 0, 0, 0.3);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.4), 0 10px 10px -5px rgba(0, 0, 0, 0.2);
    --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
}

/* Reduced Motion */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* ==========================================================================
   Base Styles
   ========================================================================== */

* {
    box-sizing: border-box;
}

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

body {
    margin: 0;
    padding: 0;
    font-family: var(--font-family-primary);
    font-size: var(--font-size-base);
    line-height: var(--line-height-normal);
    color: var(--color-text-primary);
    background-color: var(--color-background);
    transition: background-color var(--transition-base), color var(--transition-base);
}

/* Focus styles for accessibility */
:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
    border-radius: var(--radius-sm);
}

/* Selection styles */
::selection {
    background-color: var(--color-primary-light);
    color: var(--color-primary-dark);
}

/* ==========================================================================
   Typography
   ========================================================================== */

h1, h2, h3, h4, h5, h6 {
    margin: 0 0 var(--spacing-4) 0;
    font-weight: var(--font-weight-bold);
    line-height: var(--line-height-tight);
    color: var(--color-text-primary);
}

h1 { font-size: var(--font-size-4xl); }
h2 { font-size: var(--font-size-3xl); }
h3 { font-size: var(--font-size-2xl); }
h4 { font-size: var(--font-size-xl); }
h5 { font-size: var(--font-size-lg); }
h6 { font-size: var(--font-size-base); }

p {
    margin: 0 0 var(--spacing-4) 0;
    color: var(--color-text-secondary);
}

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

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

/* ==========================================================================
   Layout Components
   ========================================================================== */

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

.section {
    padding: var(--spacing-20) 0;
}

.section__header {
    text-align: center;
    margin-bottom: var(--spacing-12);
}

.section__title {
    font-size: var(--font-size-4xl);
    font-weight: var(--font-weight-bold);
    margin-bottom: var(--spacing-4);
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.section__description {
    font-size: var(--font-size-xl);
    color: var(--color-text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

/* ==========================================================================
   Header & Navigation
   ========================================================================== */

.header {
    position: sticky;
    top: 0;
    z-index: var(--z-sticky);
    background-color: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    backdrop-filter: blur(10px);
    background-color: rgba(255, 255, 255, 0.8);
}

[data-theme="dark"] .header {
    background-color: rgba(26, 26, 26, 0.8);
}

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-4) var(--spacing-6);
    max-width: 1200px;
    margin: 0 auto;
}

.nav__brand {
    display: flex;
    flex-direction: column;
}

.nav__title {
    font-size: var(--font-size-2xl);
    font-weight: var(--font-weight-bold);
    margin: 0;
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav__subtitle {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    margin: 0;
}

.nav__controls {
    display: flex;
    gap: var(--spacing-3);
    align-items: center;
}

/* ==========================================================================
   Buttons
   ========================================================================== */

.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-2);
    padding: var(--spacing-3) var(--spacing-4);
    font-size: var(--font-size-base);
    font-weight: var(--font-weight-medium);
    line-height: 1;
    border: 1px solid transparent;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    text-decoration: none;
    background-color: transparent;
    color: var(--color-text-primary);
}

.btn:hover {
    text-decoration: none;
    transform: translateY(-1px);
}

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

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

.btn--primary:hover {
    background-color: var(--color-primary-dark);
    border-color: var(--color-primary-dark);
    box-shadow: var(--shadow-md);
}

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

.btn--secondary:hover {
    background-color: var(--color-neutral-100);
    border-color: var(--color-border-strong);
    box-shadow: var(--shadow-sm);
}

[data-theme="dark"] .btn--secondary {
    background-color: var(--color-neutral-700);
}

[data-theme="dark"] .btn--secondary:hover {
    background-color: var(--color-neutral-600);
}

.btn--large {
    padding: var(--spacing-4) var(--spacing-6);
    font-size: var(--font-size-lg);
}

.btn--icon {
    padding: var(--spacing-2);
    border-radius: var(--radius-full);
}

.btn--icon .icon {
    width: 1.25rem;
    height: 1.25rem;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

.btn:disabled:hover {
    transform: none;
    box-shadow: none;
}

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

.hero {
    padding: var(--spacing-24) 0;
    background: linear-gradient(135deg, var(--color-primary-light), var(--color-secondary-light));
    position: relative;
    overflow: hidden;
}

[data-theme="dark"] .hero {
    background: linear-gradient(135deg, var(--color-neutral-800), var(--color-neutral-700));
}

.hero__content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-6);
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-12);
    align-items: center;
}

.hero__title {
    font-size: var(--font-size-6xl);
    font-weight: var(--font-weight-bold);
    margin-bottom: var(--spacing-6);
    line-height: 1.1;
}

.hero__description {
    font-size: var(--font-size-xl);
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-8);
    line-height: var(--line-height-relaxed);
}

.hero__actions {
    display: flex;
    gap: var(--spacing-4);
}

.hero__visual {
    display: flex;
    justify-content: center;
    align-items: center;
}

.dino-silhouette {
    width: 100%;
    max-width: 300px;
    height: auto;
    color: var(--color-primary);
    opacity: 0.3;
    animation: float 6s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0px); }
    50% { transform: translateY(-20px); }
}

/* ==========================================================================
   Cards & Grid
   ========================================================================== */

.dinosaur-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: var(--spacing-6);
    margin-top: var(--spacing-8);
}

.dinosaur-card {
    background-color: var(--color-surface);
    border-radius: var(--radius-xl);
    padding: var(--spacing-6);
    box-shadow: var(--shadow-base);
    transition: all var(--transition-base);
    cursor: pointer;
    border: 1px solid var(--color-border);
}

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

.dinosaur-card__header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: var(--spacing-4);
}

.dinosaur-card__title {
    font-size: var(--font-size-xl);
    font-weight: var(--font-weight-bold);
    margin: 0;
    color: var(--color-text-primary);
}

.dinosaur-card__period {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    background-color: var(--color-primary-light);
    padding: var(--spacing-1) var(--spacing-2);
    border-radius: var(--radius-full);
}

.dinosaur-card__info {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-3);
    margin-bottom: var(--spacing-4);
}

.dinosaur-card__info-item {
    display: flex;
    flex-direction: column;
}

.dinosaur-card__info-label {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-1);
}

.dinosaur-card__info-value {
    font-weight: var(--font-weight-semibold);
    color: var(--color-text-primary);
}

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

/* ==========================================================================
   Filters & Controls
   ========================================================================== */

.filters {
    background-color: var(--color-surface);
    border-radius: var(--radius-xl);
    padding: var(--spacing-6);
    margin-bottom: var(--spacing-8);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border);
}

.filters {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-4);
}

.filter-group {
    display: flex;
    flex-direction: column;
}

.filter-label {
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-medium);
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-2);
}

.filter-input,
.filter-select {
    padding: var(--spacing-3);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    font-size: var(--font-size-base);
    background-color: var(--color-background);
    color: var(--color-text-primary);
    transition: border-color var(--transition-fast);
}

.filter-input:focus,
.filter-select:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-light);
}

.range-input {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-2);
}

.range-slider {
    width: 100%;
    height: 4px;
    background: var(--color-border);
    border-radius: var(--radius-full);
    outline: none;
    -webkit-appearance: none;
}

.range-slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 16px;
    height: 16px;
    background: var(--color-primary);
    border-radius: var(--radius-full);
    cursor: pointer;
}

.range-slider::-moz-range-thumb {
    width: 16px;
    height: 16px;
    background: var(--color-primary);
    border-radius: var(--radius-full);
    cursor: pointer;
    border: none;
}

.range-values {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    text-align: center;
}

.sort-controls {
    display: flex;
    align-items: center;
    gap: var(--spacing-4);
    margin-bottom: var(--spacing-6);
}

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

.sort-select {
    padding: var(--spacing-2) var(--spacing-3);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    font-size: var(--font-size-base);
    background-color: var(--color-surface);
    color: var(--color-text-primary);
}

.results-info {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-4);
}

/* ==========================================================================
   Timeline
   ========================================================================== */

.timeline-container {
    background-color: var(--color-surface);
    border-radius: var(--radius-xl);
    padding: var(--spacing-8);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border);
}

.timeline {
    position: relative;
    margin-bottom: var(--spacing-6);
}

.timeline__track {
    display: flex;
    height: 60px;
    background: linear-gradient(to right, 
        hsl(30, 70%, 60%) 0%, 
        hsl(30, 70%, 60%) 33.33%, 
        hsl(120, 50%, 60%) 33.33%, 
        hsl(120, 50%, 60%) 66.66%, 
        hsl(60, 70%, 60%) 66.66%, 
        hsl(60, 70%, 60%) 100%
    );
    border-radius: var(--radius-lg);
    position: relative;
    overflow: hidden;
}

.timeline__period {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding: var(--spacing-2);
    position: relative;
}

.timeline__period-label {
    font-weight: var(--font-weight-semibold);
    color: white;
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.5);
}

.timeline__period-range {
    font-size: var(--font-size-xs);
    color: white;
    opacity: 0.9;
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.5);
}

.timeline__markers {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
}

.timeline__marker {
    position: absolute;
    top: 50%;
    transform: translate(-50%, -50%);
    width: 12px;
    height: 12px;
    background-color: var(--color-primary);
    border: 2px solid white;
    border-radius: var(--radius-full);
    cursor: pointer;
    transition: all var(--transition-fast);
    box-shadow: var(--shadow-sm);
}

.timeline__marker:hover {
    transform: translate(-50%, -50%) scale(1.2);
    box-shadow: var(--shadow-md);
}

.timeline__marker-tooltip {
    position: absolute;
    bottom: 100%;
    left: 50%;
    transform: translateX(-50%);
    background-color: var(--color-surface-elevated);
    color: var(--color-text-primary);
    padding: var(--spacing-2) var(--spacing-3);
    border-radius: var(--radius-md);
    font-size: var(--font-size-sm);
    white-space: nowrap;
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--color-border);
    margin-bottom: var(--spacing-2);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-fast);
}

.timeline__marker:hover .timeline__marker-tooltip {
    opacity: 1;
    visibility: visible;
}

.timeline__controls {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: var(--spacing-4);
}

.timeline__current-period {
    font-weight: var(--font-weight-semibold);
    color: var(--color-text-primary);
}

/* ==========================================================================
   Calculations
   ========================================================================== */

.calculations-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: var(--spacing-6);
    margin-bottom: var(--spacing-12);
}

.calculation-card {
    background-color: var(--color-surface);
    border-radius: var(--radius-xl);
    padding: var(--spacing-6);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border);
}

.calculation-card__title {
    font-size: var(--font-size-xl);
    font-weight: var(--font-weight-bold);
    margin-bottom: var(--spacing-3);
    color: var(--color-text-primary);
}

.calculation-card__description {
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-4);
}

.calculation-card__formula {
    font-family: var(--font-family-mono);
    font-size: var(--font-size-lg);
    background-color: var(--color-neutral-100);
    padding: var(--spacing-3);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-4);
    color: var(--color-primary);
    text-align: center;
}

[data-theme="dark"] .calculation-card__formula {
    background-color: var(--color-neutral-700);
}

.calculation-card__inputs {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-4);
    margin-bottom: var(--spacing-4);
}

.input-group {
    display: flex;
    flex-direction: column;
}

.input-label {
    font-size: var(--font-size-sm);
    font-weight: var(--font-weight-medium);
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-2);
}

.input-field,
.input-select {
    padding: var(--spacing-3);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    font-size: var(--font-size-base);
    background-color: var(--color-background);
    color: var(--color-text-primary);
    transition: border-color var(--transition-fast);
}

.input-field:focus,
.input-select:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-light);
}

.calculation-card__result {
    padding: var(--spacing-4);
    background-color: var(--color-primary-light);
    border-radius: var(--radius-md);
    border-left: 4px solid var(--color-primary);
    min-height: 60px;
    display: flex;
    align-items: center;
}

.calculation-card__result:empty::before {
    content: "Les résultats apparaîtront ici";
    color: var(--color-text-secondary);
    font-style: italic;
}

.constants-panel {
    background-color: var(--color-surface);
    border-radius: var(--radius-xl);
    padding: var(--spacing-6);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border);
}

.constants-panel__title {
    font-size: var(--font-size-xl);
    font-weight: var(--font-weight-bold);
    margin-bottom: var(--spacing-4);
}

.constants-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-4);
}

.constant-item {
    padding: var(--spacing-4);
    background-color: var(--color-neutral-100);
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
}

[data-theme="dark"] .constant-item {
    background-color: var(--color-neutral-700);
}

.constant-item__name {
    font-weight: var(--font-weight-semibold);
    color: var(--color-text-primary);
    margin-bottom: var(--spacing-2);
}

.constant-item__value {
    font-family: var(--font-family-mono);
    color: var(--color-primary);
    margin-bottom: var(--spacing-2);
}

.constant-item__reference {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    font-style: italic;
}

/* ==========================================================================
   Charts
   ========================================================================== */

.charts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: var(--spacing-6);
}

.chart-container {
    background-color: var(--color-surface);
    border-radius: var(--radius-xl);
    padding: var(--spacing-6);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border);
}

.chart-title {
    font-size: var(--font-size-lg);
    font-weight: var(--font-weight-semibold);
    margin-bottom: var(--spacing-4);
    color: var(--color-text-primary);
}

.chart {
    height: 300px;
    background-color: var(--color-background);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-text-secondary);
    border: 1px solid var(--color-border);
}

/* ==========================================================================
   Compare Section
   ========================================================================== */

.compare-container {
    background-color: var(--color-surface);
    border-radius: var(--radius-xl);
    padding: var(--spacing-6);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border);
}

.compare-selection {
    margin-bottom: var(--spacing-8);
}

.compare-selection__title {
    font-size: var(--font-size-lg);
    font-weight: var(--font-weight-semibold);
    margin-bottom: var(--spacing-4);
}

.compare-selection__grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: var(--spacing-3);
}

.compare-checkbox {
    display: flex;
    align-items: center;
    gap: var(--spacing-2);
    padding: var(--spacing-3);
    background-color: var(--color-background);
    border-radius: var(--radius-md);
    border: 1px solid var(--color-border);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.compare-checkbox:hover {
    border-color: var(--color-primary);
    background-color: var(--color-primary-light);
}

.compare-checkbox input[type="checkbox"] {
    margin: 0;
}

.compare-table-container {
    overflow-x: auto;
    margin-bottom: var(--spacing-8);
}

.compare-table {
    width: 100%;
    border-collapse: collapse;
    font-size: var(--font-size-sm);
}

.compare-table th,
.compare-table td {
    padding: var(--spacing-3);
    text-align: left;
    border-bottom: 1px solid var(--color-border);
}

.compare-table th {
    background-color: var(--color-neutral-100);
    font-weight: var(--font-weight-semibold);
    color: var(--color-text-primary);
}

[data-theme="dark"] .compare-table th {
    background-color: var(--color-neutral-700);
}

.compare-table tr:hover {
    background-color: var(--color-neutral-100);
}

[data-theme="dark"] .compare-table tr:hover {
    background-color: var(--color-neutral-700);
}

.compare-chart {
    height: 400px;
    background-color: var(--color-background);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-text-secondary);
    border: 1px solid var(--color-border);
}

/* ==========================================================================
   Documentation Tabs
   ========================================================================== */

.documentation-tabs {
    background-color: var(--color-surface);
    border-radius: var(--radius-xl);
    padding: var(--spacing-6);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border);
    margin-bottom: var(--spacing-8);
}

.tabs__nav {
    display: flex;
    gap: var(--spacing-1);
    margin-bottom: var(--spacing-6);
    border-bottom: 1px solid var(--color-border);
}

.tab__button {
    padding: var(--spacing-3) var(--spacing-4);
    background: none;
    border: none;
    font-size: var(--font-size-base);
    font-weight: var(--font-weight-medium);
    color: var(--color-text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
    border-bottom: 2px solid transparent;
    margin-bottom: -1px;
}

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

.tab__button--active {
    color: var(--color-primary);
    border-bottom-color: var(--color-primary);
}

.tab__panel {
    display: none;
}

.tab__panel--active {
    display: block;
}

.markdown-content {
    line-height: var(--line-height-relaxed);
}

.markdown-content h1,
.markdown-content h2,
.markdown-content h3,
.markdown-content h4,
.markdown-content h5,
.markdown-content h6 {
    margin-top: var(--spacing-6);
    margin-bottom: var(--spacing-3);
}

.markdown-content h1 { font-size: var(--font-size-3xl); }
.markdown-content h2 { font-size: var(--font-size-2xl); }
.markdown-content h3 { font-size: var(--font-size-xl); }

.markdown-content p {
    margin-bottom: var(--spacing-4);
}

.markdown-content code {
    background-color: var(--color-neutral-100);
    padding: var(--spacing-1) var(--spacing-2);
    border-radius: var(--radius-sm);
    font-family: var(--font-family-mono);
    font-size: var(--font-size-sm);
}

[data-theme="dark"] .markdown-content code {
    background-color: var(--color-neutral-700);
}

.markdown-content pre {
    background-color: var(--color-neutral-100);
    padding: var(--spacing-4);
    border-radius: var(--radius-md);
    overflow-x: auto;
    margin-bottom: var(--spacing-4);
}

[data-theme="dark"] .markdown-content pre {
    background-color: var(--color-neutral-700);
}

.markdown-content ul,
.markdown-content ol {
    margin-bottom: var(--spacing-4);
    padding-left: var(--spacing-6);
}

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

.documentation-actions {
    display: flex;
    gap: var(--spacing-3);
    flex-wrap: wrap;
}

/* ==========================================================================
   FAQ
   ========================================================================== */

.faq-container {
    background-color: var(--color-surface);
    border-radius: var(--radius-xl);
    padding: var(--spacing-6);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border);
}

.faq__search {
    margin-bottom: var(--spacing-6);
}

.faq__search-input {
    width: 100%;
    padding: var(--spacing-3) var(--spacing-4);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    font-size: var(--font-size-base);
    background-color: var(--color-background);
    color: var(--color-text-primary);
}

.faq__categories {
    display: flex;
    gap: var(--spacing-2);
    margin-bottom: var(--spacing-6);
    flex-wrap: wrap;
}

.faq__category-btn {
    padding: var(--spacing-2) var(--spacing-4);
    background-color: var(--color-background);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-full);
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.faq__category-btn:hover {
    border-color: var(--color-primary);
    color: var(--color-primary);
}

.faq__category-btn--active {
    background-color: var(--color-primary);
    color: white;
    border-color: var(--color-primary);
}

.faq__items {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-4);
}

.faq__item {
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    overflow: hidden;
}

.faq__item-header {
    padding: var(--spacing-4);
    background-color: var(--color-background);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: background-color var(--transition-fast);
}

.faq__item-header:hover {
    background-color: var(--color-neutral-100);
}

[data-theme="dark"] .faq__item-header:hover {
    background-color: var(--color-neutral-700);
}

.faq__item-question {
    font-weight: var(--font-weight-semibold);
    color: var(--color-text-primary);
    margin: 0;
}

.faq__item-toggle {
    width: 1.25rem;
    height: 1.25rem;
    color: var(--color-text-secondary);
    transition: transform var(--transition-fast);
}

.faq__item--open .faq__item-toggle {
    transform: rotate(180deg);
}

.faq__item-content {
    padding: 0 var(--spacing-4);
    max-height: 0;
    overflow: hidden;
    transition: all var(--transition-base);
}

.faq__item--open .faq__item-content {
    padding: var(--spacing-4);
    max-height: 500px;
}

.faq__item-answer {
    color: var(--color-text-secondary);
    line-height: var(--line-height-relaxed);
}

/* ==========================================================================
   Modal
   ========================================================================== */

.modal {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: var(--z-modal);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-4);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
}

.modal--open {
    opacity: 1;
    visibility: visible;
}

.modal__backdrop {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
}

.modal__content {
    position: relative;
    background-color: var(--color-surface);
    border-radius: var(--radius-2xl);
    box-shadow: var(--shadow-2xl);
    max-width: 600px;
    width: 100%;
    max-height: 90vh;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    transform: scale(0.9);
    transition: transform var(--transition-base);
}

.modal--open .modal__content {
    transform: scale(1);
}

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

.modal__title {
    font-size: var(--font-size-2xl);
    font-weight: var(--font-weight-bold);
    margin: 0;
}

.modal__close {
    flex-shrink: 0;
}

.modal__body {
    padding: var(--spacing-6);
    overflow-y: auto;
    flex: 1;
}

.modal__footer {
    display: flex;
    gap: var(--spacing-3);
    padding: var(--spacing-6);
    border-top: 1px solid var(--color-border);
    background-color: var(--color-neutral-100);
}

[data-theme="dark"] .modal__footer {
    background-color: var(--color-neutral-700);
}

/* ==========================================================================
   Tests Panel
   ========================================================================== */

.tests-panel {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%) scale(0.9);
    z-index: var(--z-modal);
    background-color: var(--color-surface);
    border-radius: var(--radius-2xl);
    box-shadow: var(--shadow-2xl);
    width: 90%;
    max-width: 800px;
    max-height: 90vh;
    display: flex;
    flex-direction: column;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
}

.tests-panel--open {
    opacity: 1;
    visibility: visible;
    transform: translate(-50%, -50%) scale(1);
}

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

.tests-panel__title {
    font-size: var(--font-size-xl);
    font-weight: var(--font-weight-bold);
    margin: 0;
}

.tests-panel__content {
    flex: 1;
    overflow-y: auto;
    padding: var(--spacing-6);
}

.tests-summary {
    display: flex;
    gap: var(--spacing-6);
    margin-bottom: var(--spacing-6);
    padding: var(--spacing-4);
    background-color: var(--color-neutral-100);
    border-radius: var(--radius-lg);
}

[data-theme="dark"] .tests-summary {
    background-color: var(--color-neutral-700);
}

.tests-summary__item {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.tests-summary__label {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-1);
}

.tests-summary__value {
    font-size: var(--font-size-2xl);
    font-weight: var(--font-weight-bold);
}

.tests-summary__item--success .tests-summary__value {
    color: var(--color-success);
}

.tests-summary__item--failure .tests-summary__value {
    color: var(--color-error);
}

.tests-results {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-3);
}

.test-result {
    padding: var(--spacing-4);
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
}

.test-result--success {
    background-color: hsl(140, 70%, 95%);
    border-color: var(--color-success);
}

[data-theme="dark"] .test-result--success {
    background-color: hsl(140, 70%, 15%);
}

.test-result--failure {
    background-color: hsl(0, 80%, 95%);
    border-color: var(--color-error);
}

[data-theme="dark"] .test-result--failure {
    background-color: hsl(0, 80%, 15%);
}

.test-result__name {
    font-weight: var(--font-weight-semibold);
    margin-bottom: var(--spacing-2);
}

.test-result--success .test-result__name {
    color: var(--color-success);
}

.test-result--failure .test-result__name {
    color: var(--color-error);
}

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

.test-result__details {
    margin-top: var(--spacing-2);
    padding-top: var(--spacing-2);
    border-top: 1px solid var(--color-border);
    font-family: var(--font-family-mono);
    font-size: var(--font-size-xs);
    color: var(--color-text-secondary);
}

.tests-panel__actions {
    display: flex;
    gap: var(--spacing-3);
    padding: var(--spacing-6);
    border-top: 1px solid var(--color-border);
    background-color: var(--color-neutral-100);
}

[data-theme="dark"] .tests-panel__actions {
    background-color: var(--color-neutral-700);
}

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

.toast-container {
    position: fixed;
    top: var(--spacing-6);
    right: var(--spacing-6);
    z-index: var(--z-toast);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-3);
    max-width: 400px;
}

.toast {
    background-color: var(--color-surface-elevated);
    color: var(--color-text-primary);
    padding: var(--spacing-4);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--color-border);
    display: flex;
    align-items: center;
    gap: var(--spacing-3);
    animation: slideInRight var(--transition-base);
    position: relative;
    overflow: hidden;
}

.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-primary);
}

.toast__icon {
    width: 1.25rem;
    height: 1.25rem;
    flex-shrink: 0;
}

.toast__content {
    flex: 1;
}

.toast__title {
    font-weight: var(--font-weight-semibold);
    margin-bottom: var(--spacing-1);
}

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

.toast__close {
    position: absolute;
    top: var(--spacing-2);
    right: var(--spacing-2);
    padding: var(--spacing-1);
    background: none;
    border: none;
    color: var(--color-text-secondary);
    cursor: pointer;
    border-radius: var(--radius-sm);
}

.toast__close:hover {
    background-color: var(--color-neutral-100);
    color: var(--color-text-primary);
}

[data-theme="dark"] .toast__close:hover {
    background-color: var(--color-neutral-700);
}

@keyframes slideInRight {
    from {
        transform: translateX(100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

@keyframes slideOutRight {
    from {
        transform: translateX(0);
        opacity: 1;
    }
    to {
        transform: translateX(100%);
        opacity: 0;
    }
}

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

.footer {
    background-color: var(--color-surface);
    border-top: 1px solid var(--color-border);
    padding: var(--spacing-16) 0 var(--spacing-8);
    margin-top: var(--spacing-20);
}

.footer__content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-6);
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-8);
}

.footer__title {
    font-size: var(--font-size-lg);
    font-weight: var(--font-weight-semibold);
    margin-bottom: var(--spacing-4);
}

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

.footer__links {
    list-style: none;
    padding: 0;
    margin: 0;
}

.footer__links li {
    margin-bottom: var(--spacing-2);
}

.footer__link {
    color: var(--color-text-secondary);
    transition: color var(--transition-fast);
}

.footer__link:hover {
    color: var(--color-primary);
}

.footer__link--button {
    background: none;
    border: none;
    padding: 0;
    font: inherit;
    cursor: pointer;
}

.footer__bottom {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-8) var(--spacing-6) 0;
    border-top: 1px solid var(--color-border);
    text-align: center;
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
}

/* ==========================================================================
   Responsive Design
   ========================================================================== */

/* Mobile First Approach */
@media (max-width: 768px) {
    :root {
        --font-size-base: 0.875rem;
    }
    
    .hero__content {
        grid-template-columns: 1fr;
        text-align: center;
        gap: var(--spacing-8);
    }
    
    .hero__title {
        font-size: var(--font-size-4xl);
    }
    
    .nav {
        padding: var(--spacing-3) var(--spacing-4);
    }
    
    .nav__title {
        font-size: var(--font-size-xl);
    }
    
    .filters {
        grid-template-columns: 1fr;
    }
    
    .calculations-grid {
        grid-template-columns: 1fr;
    }
    
    .charts-grid {
        grid-template-columns: 1fr;
    }
    
    .dinosaur-grid {
        grid-template-columns: 1fr;
    }
    
    .modal__content {
        margin: var(--spacing-4);
        max-height: calc(100vh - var(--spacing-8));
    }
    
    .tests-panel {
        width: 95%;
        max-height: 95vh;
    }
    
    .footer__content {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .hero__actions {
        flex-direction: column;
        align-items: center;
    }
    
    .sort-controls {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .documentation-actions {
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .hero {
        padding: var(--spacing-16) 0;
    }
    
    .section {
        padding: var(--spacing-12) 0;
    }
    
    .section__title {
        font-size: var(--font-size-3xl);
    }
    
    .modal__header,
    .modal__body,
    .modal__footer {
        padding: var(--spacing-4);
    }
    
    .tests-panel__header,
    .tests-panel__content,
    .tests-panel__actions {
        padding: var(--spacing-4);
    }
}

/* Tablet */
@media (min-width: 769px) and (max-width: 1024px) {
    .hero__content {
        gap: var(--spacing-8);
    }
    
    .dinosaur-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .calculations-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .charts-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* Desktop Large */
@media (min-width: 1440px) {
    .container {
        max-width: 1400px;
    }
    
    .hero__content {
        gap: var(--spacing-16);
    }
    
    .dinosaur-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

/* ==========================================================================
   Print Styles
   ========================================================================== */

@media print {
    .header,
    .filters,
    .sort-controls,
    .hero__actions,
    .modal,
    .tests-panel,
    .toast-container,
    .footer {
        display: none;
    }
    
    body {
        background: white;
        color: black;
    }
    
    .section {
        padding: var(--spacing-4) 0;
        page-break-inside: avoid;
    }
    
    .dinosaur-card,
    .calculation-card,
    .chart-container,
    .compare-container {
        box-shadow: none;
        border: 1px solid #ddd;
        page-break-inside: avoid;
    }
}

/* ==========================================================================
   Accessibility Utilities
   ========================================================================== */

.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;
}

/* High Contrast Mode */
@media (prefers-contrast: high) {
    :root {
        --color-border: var(--color-neutral-600);
        --color-text-secondary: var(--color-neutral-700);
    }
    
    .btn:focus-visible {
        outline-width: 3px;
    }
}