/* ==========================================================================
   Base — Reset, CSS Variables, Typographie
   ========================================================================== */

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

/* Design Tokens */
:root {
  /* Couleurs — Dark mode (defaut) */
  --bg-primary: #0a0e17;
  --bg-secondary: #111827;
  --bg-card: #1a1f2e;
  --bg-elevated: #232a3b;
  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --accent: #3b82f6;
  --accent-hover: #60a5fa;
  --accent-glow: rgba(59, 130, 246, 0.15);
  --success: #22c55e;
  --error: #ef4444;
  --border: rgba(255, 255, 255, 0.08);

  /* Typographie */
  --font-main: 'Inter', system-ui, -apple-system, sans-serif;
  --font-size-h1: clamp(2rem, 5vw, 3.5rem);
  --font-size-h2: clamp(1.5rem, 3vw, 2.25rem);
  --font-size-h3: clamp(1.25rem, 2vw, 1.5rem);
  --font-size-body: 1rem;
  --font-size-sm: 0.875rem;
  --font-size-xs: 0.75rem;

  /* Spacing */
  --section-padding: clamp(3rem, 8vw, 6rem);
  --container-max: 1280px;

  /* Transitions */
  --transition-fast: 200ms ease;
  --transition-base: 300ms ease;
  --transition-slow: 500ms ease;

  /* Borders & Shadows */
  --radius-sm: 0.5rem;
  --radius-md: 1rem;
  --radius-lg: 1.5rem;
  --shadow-card: 0 4px 20px rgba(0, 0, 0, 0.3);
}

/* Base Styles */
html {
  scroll-behavior: smooth;
  font-size: 100%;
}

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

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

h1 { font-size: var(--font-size-h1); }
h2 { font-size: var(--font-size-h2); }
h3 { font-size: var(--font-size-h3); }

p {
  color: var(--text-secondary);
  line-height: 1.6;
}

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

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

a:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

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

ul, ol {
  list-style: none;
}

button {
  cursor: pointer;
  border: none;
  background: none;
  font-family: inherit;
  font-size: inherit;
  color: inherit;
}

button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* Screen reader only utility */
.u-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;
}

.u-sr-only--focusable:focus {
  position: fixed;
  top: 0;
  left: 0;
  width: auto;
  height: auto;
  padding: 0.75rem 1.5rem;
  margin: 0;
  overflow: visible;
  clip: auto;
  white-space: normal;
  background-color: var(--accent);
  color: #ffffff;
  font-weight: 600;
  z-index: 10000;
}