:root {
    --bg-color: #f0f2f5;
    --container-bg-color: white;
    --text-color: #333;
    --number-bg-color: #eee;
    --button-bg-color: #007bff;
    --button-text-color: white;
    --button-hover-bg-color: #0056b3;
}

body.dark-mode {
    --bg-color: #1a1a1a;
    --container-bg-color: #2a2a2a;
    --text-color: #f0f2f5;
    --number-bg-color: #444;
    --button-bg-color: #0056b3;
    --button-hover-bg-color: #007bff;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    background-color: var(--bg-color);
    transition: background-color 0.3s ease;
}

.container {
    position: relative;
    text-align: center;
    padding: 2rem;
    background-color: var(--container-bg-color);
    border-radius: 10px;
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
    transition: background-color 0.3s ease;
}

#theme-toggle {
    position: absolute;
    top: 1rem;
    right: 1rem;
    padding: 0.5rem;
    font-size: 0.8rem;
    color: var(--button-text-color);
    background-color: var(--button-bg-color);
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

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

h1 {
    margin-bottom: 2rem;
    color: var(--text-color);
}

.lotto-numbers {
    display: flex;
    justify-content: center;
    margin-bottom: 2rem;
}

.number {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 50px;
    height: 50px;
    margin: 0 5px;
    border-radius: 50%;
    background-color: var(--number-bg-color);
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--text-color);
    transition: background-color 0.3s ease, color 0.3s ease;
}

#generate-btn {
    padding: 1rem 2rem;
    font-size: 1rem;
    color: var(--button-text-color);
    background-color: var(--button-bg-color);
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

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