/* Base CSS - Reset, Variables, Typography */

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

/* Variables CSS */
:root {
    /* Couleurs principales */
    --color-primary: #667eea;
    --color-primary-dark: #5a67d8;
    --color-primary-light: #a3bffa;

    /* Couleurs neutres */
    --color-surface: #ffffff;
    --color-surface-alt: #f7fafc;
    --color-border: #e2e8f0;
    --color-text: #1a202c;
    --color-text-light: #718096;
    --color-text-lighter: #a0aec0;

    /* Couleurs statuts */
    --color-success: #48bb78;
    --color-warning: #ed8936;
    --color-error: #f56565;
    --color-info: #4299e1;

    /* Espacements */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;
    --spacing-2xl: 48px;

    /* Bordures */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-full: 9999px;

    /* Ombres */
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 200ms ease;
    --transition-slow: 300ms ease;
}

/* Typographie */
html {
    font-size: 16px;
    line-height: 1.5;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    color: var(--color-text);
    background: var(--color-surface-alt);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.2;
    margin-bottom: var(--spacing-md);
}

h1 { font-size: 2rem; }
h2 { font-size: 1.5rem; }
h3 { font-size: 1.25rem; }
h4 { font-size: 1.125rem; }
h5 { font-size: 1rem; }
h6 { font-size: 0.875rem; }

p {
    margin-bottom: var(--spacing-md);
}

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

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

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

/* Accessibilité */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

/* Focus visible pour navigation clavier */
*:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

/* Skip to main content */
.skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    background: var(--color-primary);
    color: white;
    padding: var(--spacing-sm) var(--spacing-md);
    text-decoration: none;
    z-index: 100;
}

.skip-link:focus {
    top: 0;
}

/* Utilities */
.visually-hidden {
    position: absolute !important;
    clip: rect(1px, 1px, 1px, 1px);
    padding: 0 !important;
    border: 0 !important;
    height: 1px !important;
    width: 1px !important;
    overflow: hidden;
}