:root {
    --bg-color: #f0f2f5;
    --text-color: #333;
    --header-bg: #fff;
    --header-border: #ddd;
    --card-bg: #fff;
    --button-bg: #4CAF50;
    --button-text: #fff;
    --button-hover-bg: #45a049;
}

[data-theme="dark"] {
    --bg-color: #121212;
    --text-color: #f0f2f5;
    --header-bg: #1f1f1f;
    --header-border: #333;
    --card-bg: #1f1f1f;
    --button-bg: #663399;
    --button-text: #fff;
    --button-hover-bg: #5a2d8a;
}

body {
    font-family: 'Arial', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    margin: 0;
    padding: 0;
    transition: background-color 0.3s, color 0.3s;
}

header {
    background-color: var(--header-bg);
    padding: 20px;
    text-align: center;
    border-bottom: 1px solid var(--header-border);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

h1, h2, h3 {
    margin: 0;
}

main {
    padding: 20px;
}

#lotto-generator {
    background-color: var(--card-bg);
    padding: 20px;
    margin-bottom: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

#generate-lotto-btn {
    background-color: var(--button-bg);
    color: var(--button-text);
    padding: 10px 20px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 16px;
    transition: background-color 0.3s;
}

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

#lotto-numbers-display {
    margin-top: 20px;
    font-size: 24px;
    font-weight: bold;
    text-align: center;
}

#theme-toggle {
    background-color: var(--button-bg);
    color: var(--button-text);
    padding: 8px 16px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 14px;
    transition: background-color 0.3s;
}

#theme-toggle:hover {
    background-color: var(--button-hover-bg);
}