@charset "utf-8";

:root {
  /* Typography */
  --font-system: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Segoe UI", 
                Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: "SF Mono", Monaco, Inconsolata, "Fira Mono", monospace;
  
  /* Color System - WCAG AA/AAA Compliant */
  --color-primary-900: #000814;
  --color-primary-500: #003566;
  --color-primary-300: #0077b6;
  --color-primary-100: #90e0ef;
  --color-accent-500: #ff6d00;
  --color-accent-300: #ff9e00;
  --color-accent-100: #ffd166;
  
  /* Semantic Colors */
  --color-text-primary: #1a1a1a;
  --color-text-secondary: #4a4a4a;
  --color-text-light: #ffffff;
  --color-background: #f8f9fa;
  --color-surface: #ffffff;
  --color-border: rgba(0, 0, 0, 0.1);
  
  /* Interactive Colors */
  --color-link: #0066cc;
  --color-link-hover: #004085;
  --color-focus: #0056b3;
  --color-danger: #dc3545;
  
  /* Button Glow Effects */
  --btn-liquid-glow: 0 0 10px rgba(0, 200, 255, 0.5);
  --btn-liquid-glow-hover: 0 0 15px rgba(0, 200, 255, 0.8);
  --btn-liquid-glow-strong: 
    0 0 15px rgba(0, 255, 255, 0.5),
    0 0 30px rgba(0, 153, 255, 0.3),
    0 0 20px rgba(255, 140, 0, 0.6);
  
  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-smooth: 400ms cubic-bezier(0.25, 0.46, 0.45, 0.94);
  
  /* Shadows - Optimized for Paint Performance */
  --shadow-sm: 0 1px 2px 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);
  
  /* Layout */
  --container-max: 1200px;
  --container-wide: 1600px;
  --gutter-base: clamp(0.75rem, 2vw, 1rem);
  --gutter-lg: clamp(1rem, 3vw, 1.5rem);
  --gutter-xl: clamp(1.5rem, 4vw, 2rem);
  
  /* Typography Scale (rem) */
  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 1.875rem;
  --text-4xl: 2.25rem;
  
  /* Spacing Scale (rem) */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  
  /* Z-index System */
  --z-negative: -1;
  --z-base: 1;
  --z-elevated: 10;
  --z-sticky: 100;
  --z-overlay: 1000;
  --z-modal: 2000;
  
  /* Layout Heights */
  --footer-height: 76px;
  
  /* Performance Hints */
  --gpu-transform: translate3d(0, 0, 0);
}

/* ============================================
   BASE RESET & ACCESSIBILITY
   ============================================ */
*, 
*::before, 
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  overflow-x: hidden;
  font-size: 100%;
  -webkit-text-size-adjust: 100%;
  -webkit-tap-highlight-color: transparent;
  scroll-behavior: smooth;
  scroll-padding-top: var(--space-8);
}

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

/* Focus Management */
:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 2px;
  border-radius: 2px;
}

:focus:not(:focus-visible) {
  outline: none;
}

/* Selection Styling */
::selection {
  background-color: var(--color-accent-100);
  color: var(--color-primary-900);
  text-shadow: none;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: var(--space-4);
  color: var(--color-text-primary);
}

h1 { font-size: clamp(var(--text-2xl), 5vw, var(--text-4xl)); }
h2 { font-size: clamp(var(--text-xl), 4vw, var(--text-3xl)); }
h3 { font-size: clamp(var(--text-lg), 3vw, var(--text-2xl)); }
h4 { font-size: clamp(var(--text-base), 2.5vw, var(--text-xl)); }
h5 { font-size: var(--text-lg); }
h6 { font-size: var(--text-base); }

p {
  margin-bottom: var(--space-4);
  max-width: 65ch;
}

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

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

strong, b {
  font-weight: 700;
}