:root {
    --bg-color: #f0f0f0;
    --text-color: #333;
    --container-bg: #fff;
    --button-bg: #4CAF50;
    --button-text: white;
    --number-bg: #fff;
    --number-shadow: rgba(0, 0, 0, 0.1);
}

body.dark-mode {
    --bg-color: #1a1a1a;
    --text-color: #f0f0f0;
    --container-bg: #2d2d2d;
    --button-bg: #45a049;
    --button-text: #fff;
    --number-bg: #3d3d3d;
    --number-shadow: rgba(0, 0, 0, 0.5);
}

body {
    font-family: sans-serif;
    text-align: center;
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: background-color 0.3s, color 0.3s;
}

header {
    padding: 2rem 0;
}

main {
    padding: 2rem 0;
}

.number-container {
    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;
    box-shadow: 0 2px 5px var(--number-shadow);
    color: var(--text-color);
}

button {
    padding: 0.8rem 1.5rem;
    border: none;
    background-color: var(--button-bg);
    color: var(--button-text);
    font-size: 1rem;
    cursor: pointer;
    border-radius: 5px;
}

.history-section {
    padding: 2rem 0;
}

#history-list {
    list-style: none;
    padding: 0;
}

#theme-toggle {
    position: absolute;
    top: 1rem;
    right: 1rem;
}