:root {
    --bg-color: #f0f0f0;
    --text-color: #333;
    --container-bg: transparent;
    --number-bg: #fff;
    --number-border: #ccc;
    --btn-bg: #4CAF50;
    --btn-text: #fff;
    --toggle-btn-bg: #555;
}

body.dark-mode {
    --bg-color: #121212;
    --text-color: #e0e0e0;
    --number-bg: #333;
    --number-border: #555;
    --toggle-btn-bg: #ccc;
}

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;
}

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

.number {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background-color: var(--number-bg);
    border: 2px solid var(--number-border);
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 24px;
    margin: 5px;
    transition: background-color 0.3s, border-color 0.3s;
}

#generator-btn {
    padding: 10px 20px;
    font-size: 18px;
    border: none;
    border-radius: 5px;
    background-color: var(--btn-bg);
    color: var(--btn-text);
    cursor: pointer;
}

#theme-toggle {
    padding: 5px 10px;
    font-size: 14px;
    border: none;
    border-radius: 3px;
    background-color: var(--toggle-btn-bg);
    color: var(--bg-color);
    cursor: pointer;
    margin-bottom: 20px;
}