/* Общие стили */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Arial', sans-serif;
    line-height: 1.6;
    transition: background-color 0.3s, color 0.3s;
}

/* Светлая тема */
body.light {
    background-color: #f4f4f4;
    color: #333;
}

body.light header,
body.light main {
    background-color: white;
    border: 1px solid #ddd;
}

/* Тёмная тема */
body.dark {
    background-color: #1a1a1a;
    color: #e0e0e0;
}

body.dark header,
body.dark main {
    background-color: #2d2d2d;
    border: 1px solid #555;
}

.container {
    width: 90%;
    max-width: 800px;
    margin: 20px auto;
    padding: 20px;
}

header {
    padding: 20px;
    margin-bottom: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

nav {
    margin: 20px 0;
    text-align: center;
}

nav a {
    margin: 0 10px;
    text-decoration: none;
    color: #007bff;
    font-weight: bold;
}

nav a:hover {
    text-decoration: underline;
}

body.dark nav a {
    color: #00d4ff;
}

main {
    padding: 20px;
    border-radius: 8px;
    margin-bottom: 20px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

footer {
    text-align: center;
    margin-top: 30px;
    padding: 10px;
    font-size: 0.9em;
    color: #777;
}

body.dark footer {
    color: #aaa;
}