body {
    font-family: 'Arial', sans-serif;
    transition: background-color 0.5s, color 0.5s;
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

.dark-mode {
    background-color: #333;
    color: #fff;
}

header {
    background-color: #333;
    color: #fff;
    padding: 20px;
    text-align: right;
}

main {
    padding: 20px;
}

img {
    max-width: 100%;
    height: auto;
}

.toggle-btn {
    position: fixed;
    top: 20px;
    right: 20px;
    cursor: pointer;
    background: #fff;
    color: #333;
    border: none;
    padding: 8px 16px;
    font-size: 16px;
    border-radius: 4px;
}

.icon {
    margin-right: 8px;
    font-size: 20px;
}