:root {
    --bg-color: #f0f0f0;
    --text-color: #333;
    --surface-color: #f9f9f9;
    --border-color: #ccc;
    --accent-color: #4CAF50;
    --accent-hover: #45a049;
    --number-bg: #eee;
}

[data-theme="dark"] {
    --bg-color: #121212;
    --text-color: #e0e0e0;
    --surface-color: #1e1e1e;
    --border-color: #333;
    --accent-color: #66BB6A;
    --accent-hover: #81C784;
    --number-bg: #333;
}

body {
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100vh;
    margin: 0;
    background-color: var(--bg-color);
    background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3%3Cfilter id='noiseFilter'%3%3CfeTurbulence type='fractalNoise' baseFrequency='0.65' numOctaves='3' stitchTiles='stitch'/%3%3C/filter%3%3Crect width='100%25' height='100%25' filter='url(%23noiseFilter)'/%3%3C/svg%3");
    background-blend-mode: overlay;
    color: var(--text-color);
    transition: background-color 0.3s, color 0.3s;
}

h1 {
    color: var(--text-color);
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: 2rem;
    text-align: center;
    background: linear-gradient(to bottom right, var(--text-color), var(--accent-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}