:root {
    --bg-color: #f0f0f0;
    --text-color: #333;
    --container-bg: #fff;
    --number-bg: #fff;
    --number-border: #ccc;
    --button-bg: #efefef;
    --button-text: #000;
}

body.dark-mode {
    --bg-color: #1a1a1a;
    --text-color: #f0f0f0;
    --container-bg: #2d2d2d;
    --number-bg: #444;
    --number-border: #555;
    --button-bg: #444;
    --button-text: #fff;
}

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

.container {
    text-align: center;
    background-color: var(--container-bg);
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

.numbers {
    display: flex;
    justify-content: center;
    margin-bottom: 20px;
}

.number {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background-color: var(--number-bg);
    border: 1px solid var(--number-border);
    display: flex;
    justify-content: center;
    align-items: center;
    margin: 0 5px;
    font-size: 24px;
    color: var(--text-color);
}

button {
    padding: 10px 20px;
    font-size: 18px;
    cursor: pointer;
    background-color: var(--button-bg);
    color: var(--button-text);
    border: 1px solid var(--number-border);
    border-radius: 5px;
}

#theme-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
}