body { font-family: Arial, sans-serif; background: #f4f4f4; margin: 0; padding: 0; }
header { background: #0074D9; color: #fff; padding: 1em 0; text-align: center; }
nav a { color: #fff; text-decoration: none; margin: 0 10px; }
nav a:hover { text-decoration: underline; }
nav a.button {
    background: #fff;
    color: #0074D9;
    padding: 5px 12px;
    border-radius: 4px;
    margin-left: 8px;
    border: 1px solid #0074D9;
    transition: background 0.2s, color 0.2s;
    font-weight: bold;
}
nav a.button:hover {
    background: #0074D9;
    color: #fff;
}
main { max-width: 600px; margin: 2em auto; background: #fff; padding: 2em; border-radius: 8px; box-shadow: 0 2px 8px rgba(0,0,0,0.1); }