:root {
    color-scheme: light dark;

    --background: #f4f7fb;
    --foreground: #222;
    --accent: #2563eb;
    --card: white;
}

@media (prefers-color-scheme: dark) {
    :root {
        --background: #181a1f;
        --foreground: #f2f2f2;
        --card: #252933;
    }
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    min-height: 100vh;

    display: grid;
    place-items: center;

    font-family: system-ui, sans-serif;

    background: var(--background);
    color: var(--foreground);
}

.container {
    text-align: center;

    background: var(--card);

    padding: 3rem;
    border-radius: 16px;

    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15);

    max-width: 40rem;
    width: min(90%, 40rem);
}

h1 {
    margin-top: 0;
    font-size: 3rem;
}

.subtitle {
    color: gray;
    margin-bottom: 2rem;
}

.button {
    display: inline-block;

    text-decoration: none;

    background: var(--accent);
    color: white;

    padding: 0.8rem 1.4rem;
    border-radius: 8px;

    transition: transform 0.15s ease,
                opacity 0.15s ease;
}

.button:hover {
    opacity: 0.9;
    transform: translateY(-2px);
}