/* ============================================================
   BASE.CSS — Reset, CSS variables, and global base styles
   ============================================================ */

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

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

:root {
    --bg-primary: #05060f;
    --bg-secondary: #080b16;
    --bg-tertiary: #0c0f1e;
    --bg-card: #0e1121;
    --bg-overlay: rgba(5, 6, 15, 0.97);

    --text-primary: #e8eeff;
    --text-secondary: #8899bb;
    --text-muted: #3d4f6e;
    --text-accent: #06b6d4;

    --accent-primary: #06b6d4;
    --accent-secondary: #8b5cf6;
    --accent-tertiary: #10b981;

    --border-color: #1a2240;
    --border-hover: #2a3560;

    --success: #10b981;
    --warning: #f59e0b;
    --error: #ef4444;

    --font-heading: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-body: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;

    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    --font-size-4xl: 2.25rem;
    --font-size-5xl: 3rem;

    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    --space-3xl: 4rem;
    --space-4xl: 6rem;

    --container-max-width: 1200px;
    --container-padding: 2rem;
    --section-padding: 6rem 0;

    --transition-fast: 0.15s ease-in-out;
    --transition-base: 0.3s ease-in-out;
    --transition-slow: 0.5s ease-in-out;

    --radius-sm: 0.25rem;
    --radius-base: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-full: 9999px;

    --z-sticky: 1020;
    --z-fixed: 1030;
    --z-modal-backdrop: 1040;
    --z-modal: 1050;
    --z-tooltip: 1070;
}

[data-theme="light"] {
    --bg-primary: #f0f2f8;
    --bg-secondary: #e8eaf2;
    --bg-tertiary: #dde0ee;
    --bg-card: #e4e7f2;
    --bg-overlay: rgba(240, 242, 248, 0.97);

    --text-primary: #1a1d2e;
    --text-secondary: #3d4a6b;
    --text-muted: #6c7a9c;
    --text-accent: #0d6efd;

    --accent-primary: #0d6efd;
    --accent-secondary: #6610f2;
    --accent-tertiary: #198754;

    --border-color: #c8cedf;
    --border-hover: #a8b0cc;

    --success: #198754;
    --warning: #ffc107;
    --error: #dc3545;
}

/* ── Accessibility ── */
.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;
}

.icon {
    width: 1.5rem;
    height: 1.5rem;
    fill: currentColor;
}

/* ── Print ── */
@media print {
    .navbar, .back-to-top, .scroll-indicator, .fab-group { display: none; }
    body { background: white; color: black; }
    .section-title::after { background: black; }
}

/* ── Reduced motion ── */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    html { scroll-behavior: auto; }
}