/* ===== Base / Design Tokens ===== */
:root {
    /* Colors */
    --bg: #0b1220; /* page background */
    --panel: #0f172a; /* header/footer/panels */
    --surface: #10192f; /* card surface */
    --surface-2: #0c1426; /* deeper surface */
    --ink: #e5e7eb; /* primary text */
    --ink-2: #cbd5e1; /* secondary text */
    --muted: #94a3b8;
    --brand: #7c5cff; /* accent */
    --brand-2: #22d3ee; /* secondary accent */
    --ok: #22c55e;
    --warn: #f59e0b;
    --err: #ef4444;
    /* Shadows & Radii */
    --shadow-1: 0 8px 22px rgba(2,6,23,.25);
    --shadow-2: 0 10px 34px rgba(2,6,23,.35);
    --rad: 16px;
    --rad-sm: 10px;
    --rad-lg: 22px;
    /* Spacing & Container */
    --gap: 1rem;
    --gap-2: 1.5rem;
    --gap-3: 2rem;
    --container: 1100px;
    /* Typography */
    --font: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, Arial, "Noto Sans", "Liberation Sans", sans-serif;
    --mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", monospace;
    --h1: clamp(28px, 3vw, 36px);
    --h2: clamp(22px, 2.2vw, 28px);
    --h3: clamp(18px, 1.8vw, 22px);
    --text: 16px;
}

/* ===== Reset / Base ===== */
* {
    box-sizing: border-box
}

html, body {
    height: 100%
}

html {
    scroll-behavior: smooth
}

body {
    margin: 0;
    color: var(--ink);
    background: linear-gradient(160deg,#0a1020,#0b1220 35%,#0c1426);
    font: 400 var(--text)/1.6 var(--font);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

a {
    color: var(--brand);
    text-decoration: none
}

    a:hover, a:focus {
        opacity: .9
    }

.container {
    max-width: var(--container);
    margin: 0 auto;
    padding: 0 var(--gap)
}

/* ===== Headings ===== */
h1 {
    font-size: var(--h1);
    margin: 1.2rem 0 .6rem
}

h2 {
    font-size: var(--h2);
    margin: 1rem 0 .5rem
}

    h2.del {
        text-decoration: line-through;
        color: #ef4444;
    }

h3 {
    font-size: var(--h3);
    margin: .8rem 0 .4rem
}

p {
    color: var(--ink-2)
}

/* ===== Page frame ===== */
.site-header {
    background: radial-gradient(1000px 400px at 10% -20%, rgba(124,92,255,.25), transparent 60%), radial-gradient(800px 300px at 90% -20%, rgba(34,211,238,.18), transparent 60%), var(--panel);
    border-bottom: 1px solid rgba(148,163,184,.15);
    position: sticky;
    top: 0;
    z-index: 50;
    box-shadow: var(--shadow-1);
}

.site-footer {
    background: var(--panel);
    border-top: 1px solid rgba(148,163,184,.15);
    margin-top: var(--gap-3);
    color: var(--muted);
}

/* Skip link for a11y */
.skip {
    position: absolute;
    left: -9999px;
    top: auto
}

    .skip:focus {
        left: var(--gap);
        top: var(--gap);
        background: #fff;
        color: #000;
        padding: .5rem .75rem;
        border-radius: 8px
    }

/* Main area spacing */
main.container {
    padding: var(--gap-2) 0;
}