/* ============================================================================
   base.css — reset, typography, focus, accessibility primitives
   ============================================================================ */

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

html {
    -webkit-text-size-adjust: 100%;
    color-scheme: light dark;
}

body {
    font-family: var(--font-body);
    font-size: var(--text-base);
    line-height: var(--leading-normal);
    color: var(--text-primary);
    background: var(--bg-secondary);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
    min-height: 100vh;
    transition: background-color var(--duration) var(--ease),
                color var(--duration) var(--ease);
}

img, picture, svg, video, canvas {
    display: block;
    max-width: 100%;
    height: auto;
}

button { font: inherit; cursor: pointer; }
input, select, textarea { font: inherit; }

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-display);
    font-weight: 400;
    line-height: var(--leading-tight);
    color: var(--text-primary);
    letter-spacing: -0.01em;
}
h1 { font-size: var(--text-4xl); }
h2 { font-size: var(--text-2xl); }
h3 { font-size: var(--text-xl); }
h4 { font-size: var(--text-lg); }

p { line-height: var(--leading-normal); }

a {
    color: var(--accent-600);
    text-decoration: none;
    transition: color var(--duration-fast) var(--ease);
}
a:hover { color: var(--accent-700); }

code {
    font-family: var(--font-mono);
    font-size: 0.9em;
    background: var(--bg-tertiary);
    padding: 0.1em 0.4em;
    border-radius: var(--radius-sm);
    color: var(--text-primary);
}

pre {
    font-family: var(--font-mono);
    font-size: 0.85em;
    background: var(--bg-tertiary);
    padding: var(--space-3) var(--space-4);
    border-radius: var(--radius-md);
    overflow-x: auto;
    line-height: var(--leading-snug);
}

hr {
    border: 0;
    border-top: 1px solid var(--border-default);
    margin: var(--space-6) 0;
}

/* Visible focus indicator that always wins */
:focus-visible {
    outline: 2px solid var(--accent-500);
    outline-offset: 3px;
    border-radius: var(--radius-sm);
}

/* Default browser focus removed only when focus-visible is supported */
:focus:not(:focus-visible) { outline: none; }

/* Skip-to-content link */
.skip-link {
    position: absolute;
    left: -10000px;
    top: var(--space-2);
    background: var(--accent-500);
    color: var(--accent-fg);
    padding: var(--space-2) var(--space-4);
    border-radius: var(--radius-md);
    z-index: var(--z-toast);
    font-weight: 600;
}
.skip-link:focus { left: var(--space-2); }

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

/* Utilities */
.muted { color: var(--text-tertiary); }
.text-secondary { color: var(--text-secondary); }
.text-center { text-align: center; }

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

/* Selection */
::selection {
    background: var(--accent-200);
    color: var(--accent-700);
}
[data-theme="dark"] ::selection,
.dark ::selection {
    background: var(--accent-700);
    color: var(--accent-fg);
}