:root {
    --bg: #0f172a;
    --card: #1e293b;
    --accent: #38bdf8;
    --text: #e2e8f0;
    --muted: #94a3b8;
}
* { box-sizing: border-box; }
body {
    margin: 0;
    min-height: 100vh;
    display: grid;
    place-items: center;
    background: radial-gradient(circle at 50% 0%, #1e293b, var(--bg));
    color: var(--text);
    font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}
.card {
    background: var(--card);
    padding: 3rem 3.5rem;
    border-radius: 16px;
    box-shadow: 0 20px 50px rgba(0,0,0,.45);
    text-align: center;
    max-width: 640px;
}
h1 { font-size: 2rem; margin: 0 0 1rem; }
h1 span { color: var(--accent); }
p { line-height: 1.6; }
.muted { color: var(--muted); font-size: .95rem; }
.btn {
    display: inline-block;
    margin-top: 1.5rem;
    padding: .7rem 1.4rem;
    background: var(--accent);
    color: #0f172a;
    text-decoration: none;
    border-radius: 8px;
    font-weight: 600;
}
.btn:hover { filter: brightness(1.1); }