:root {
    --bg-color: #f0f0f0;
    --container-bg: white;
    --text-color: #333;
    --button-bg: #007bff;
    --button-hover: #0056b3;
    --shadow: rgba(0,0,0,0.1);
}

body.dark-mode {
    --bg-color: #121212;
    --container-bg: #1e1e1e;
    --text-color: #e0e0e0;
    --button-bg: #3700b3;
    --button-hover: #6200ee;
    --shadow: 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 {
    text-align: center;
    background-color: var(--container-bg);
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 4px 8px var(--shadow);
    transition: background-color 0.3s, box-shadow 0.3s;
    position: relative;
}

.mode-toggle {
    position: absolute;
    top: 1rem;
    right: 1rem;
    background: none;
    border: 1px solid var(--text-color);
    color: var(--text-color);
    padding: 0.5rem;
    border-radius: 5px;
    cursor: pointer;
    font-size: 0.8rem;
}

h1 {
    margin-bottom: 2rem;
}

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

#generate-button {
    padding: 0.8rem 1.5rem;
    font-size: 1rem;
    border: none;
    border-radius: 5px;
    background-color: var(--button-bg);
    color: white;
    cursor: pointer;
    transition: background-color 0.3s;
}

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