:root {
    --bg-color: #f0f0f0;
    --container-bg: #fff;
    --text-color: #333;
    --number-bg: #eee;
    --btn-bg: #4CAF50;
    --btn-text: white;
}

body.dark-mode {
    --bg-color: #1a1a1a;
    --container-bg: #2d2d2d;
    --text-color: #f0f0f0;
    --number-bg: #444;
    --btn-bg: #45a049;
}

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

.container {
    text-align: center;
    background-color: var(--container-bg);
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    transition: background-color 0.3s;
}

.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

h1 {
    margin: 0;
}

.theme-btn {
    background: none;
    border: none;
    font-size: 24px;
    cursor: pointer;
    padding: 5px;
    border-radius: 5px;
    transition: background-color 0.2s;
}

.theme-btn:hover {
    background-color: rgba(0, 0, 0, 0.1);
}

body.dark-mode .theme-btn:hover {
    background-color: rgba(255, 255, 255, 0.1);
}

.lotto-numbers {
    display: flex;
    justify-content: center;
    margin-bottom: 20px;
}

.number {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background-color: var(--number-bg);
    display: flex;
    justify-content: center;
    align-items: center;
    margin: 0 5px;
    font-size: 20px;
    font-weight: bold;
    transition: background-color 0.3s;
}

#generate-btn {
    padding: 10px 20px;
    font-size: 16px;
    cursor: pointer;
    border: none;
    background-color: var(--btn-bg);
    color: var(--btn-text);
    border-radius: 5px;
    transition: background-color 0.3s;
}