:root {
    --bg-color: #f0f0f0;
    --text-color: #333;
    --container-bg: #fff;
}

[data-theme="dark"] {
    --bg-color: #1a1a1a;
    --text-color: #f0f0f0;
    --container-bg: #2d2d2d;
}

body {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: background-color 0.3s, color 0.3s;
    font-family: sans-serif;
}

h1 {
    text-align: center;
    margin-bottom: 2rem;
}

#theme-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
    padding: 10px 15px;
    cursor: pointer;
    border: none;
    border-radius: 5px;
    background-color: var(--text-color);
    color: var(--bg-color);
    font-weight: bold;
    transition: 0.3s;
}