:root {
    --bg-color: #f0f0f0;
    --container-bg: white;
    --text-color: #333;
    --shadow-color: rgba(0, 0, 0, 0.1);
}

body.dark-mode {
    --bg-color: #1a1a1a;
    --container-bg: #2d2d2d;
    --text-color: #f0f0f0;
    --shadow-color: rgba(0, 0, 0, 0.5);
}

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);
    margin: 0;
    transition: background-color 0.3s, color 0.3s;
}

.container {
    position: relative;
    text-align: center;
    background-color: var(--container-bg);
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 0 10px var(--shadow-color);
    transition: background-color 0.3s, box-shadow 0.3s;
}

#theme-toggle {
    position: absolute;
    top: 10px;
    right: 10px;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    padding: 5px;
    border-radius: 50%;
    transition: background-color 0.3s;
}

#theme-toggle:hover {
    background-color: var(--shadow-color);
}

#numbers-container {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin: 2rem 0;
}

.number {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 1.2rem;
    font-weight: bold;
    color: white;
    text-shadow: 1px 1px 2px rgba(0,0,0,0.5);
}

#generate-btn {
    padding: 0.8rem 1.5rem;
    font-size: 1rem;
    border: none;
    border-radius: 5px;
    background-color: #4CAF50;
    color: white;
    cursor: pointer;
    transition: background-color 0.3s;
}

#generate-btn:hover {
    background-color: #45a049;
}