:root {
    --bg-color: #f0f0f0;
    --container-bg: white;
    --text-color: #333;
    --number-bg: #eee;
    --button-bg: #4CAF50;
    --button-hover: #45a049;
    --shadow: 0 0 20px rgba(0, 0, 0, 0.1);
}

body.dark-mode {
    --bg-color: #1a1a1a;
    --container-bg: #2d2d2d;
    --text-color: #f0f0f0;
    --number-bg: #444;
    --button-bg: #2e7d32;
    --button-hover: #1b5e20;
    --shadow: 0 0 20px rgba(0, 0, 0, 0.5);
}

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

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

h1 {
    margin-bottom: 2rem;
    color: var(--text-color);
}

.numbers {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 2rem;
}

.number {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background-color: var(--number-bg);
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--text-color);
    transition: background-color 0.3s, color 0.3s;
}

.controls {
    margin-top: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

button {
    background-color: var(--button-bg);
    color: white;
    padding: 1rem 2rem;
    border: none;
    border-radius: 5px;
    font-size: 1rem;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

button:hover {
    background-color: var(--button-hover);
}

#theme-toggle {
    background-color: transparent;
    border: 1px solid var(--text-color);
    color: var(--text-color);
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.8rem;
    align-self: flex-end;
}