:root {
    --bg-color: #f0f0f0;
    --container-bg: #ffffff;
    --text-color: #333333;
    --shadow-color: rgba(0, 0, 0, 0.1);
    --btn-bg: #007bff;
    --btn-hover: #0056b3;
}

body.dark-mode {
    --bg-color: #1a1a1a;
    --container-bg: #2d2d2d;
    --text-color: #f0f0f0;
    --shadow-color: rgba(0, 0, 0, 0.5);
    --btn-bg: #375a7f;
    --btn-hover: #2b4764;
}

body {
    font-family: sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    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 0 10px var(--shadow-color);
    transition: background-color 0.3s, box-shadow 0.3s;
}

.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: 1.5rem;
    color: white;
    font-weight: bold;
    box-shadow: 0 2px 5px rgba(0,0,0,0.2);
}

#generate-btn, #theme-toggle {
    padding: 0.8rem 1.5rem;
    font-size: 1rem;
    border: none;
    border-radius: 5px;
    background-color: var(--btn-bg);
    color: white;
    cursor: pointer;
    transition: background-color 0.3s;
    margin: 0.5rem;
}

#generate-btn:hover, #theme-toggle:hover {
    background-color: var(--btn-hover);
}

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