body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    background: #f5f5f5;
    color: #333;
}

header {
    background: #1a1a1a;
    padding: 20px;
    text-align: center;
}

.logo {
    height: 60px;
}

main {
    max-width: 800px;
    margin: 40px auto;
    text-align: center;
}

.hint {
    margin-top: 20px;
    color: #666;
}

.btn {
    display: inline-block;
    margin: 15px;
    padding: 12px 25px;
    background: #0078d4;
    color: white;
    text-decoration: none;
    border-radius: 6px;
    font-size: 18px;
}

.btn:hover {
    background: #005fa3;
}

footer {
    margin-top: 40px;
    text-align: center;
    color: #777;
}

.reg-mark {
    font-size: 0.6em;
    vertical-align: super;
    margin-left: 2px;
    opacity: 0.85;
}