* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: #333;
    background: #f5f5f5;
}
.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
}
.header-image {
    width: 100%;
    max-width: 100%;
    height: auto;
    margin-bottom: 30px;
    display: block;
}
.card {
    background: white;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    padding: 30px;
    margin-bottom: 20px;
}
.submit-btn {
    margin-top: 30px;
}
h1, h2 {
    color: #2c3e50;
    margin-bottom: 20px;
}
h1 {
    font-size: 28px;
}
h2 {
    font-size: 22px;
}
.form-group {
    margin-bottom: 20px;
}
label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: #555;
}
input[type="text"],
input[type="email"],
input[type="password"] {
    width: 100%;
    padding: 12px;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-size: 16px;
    transition: border-color 0.3s;
}
input[type="text"]:focus,
input[type="email"]:focus,
input[type="password"]:focus {
    outline: none;
    border-color: #3498db;
}
.btn {
    display: inline-block;
    padding: 12px 24px;
    background: #3498db;
    color: white;
    border: none;
    border-radius: 4px;
    font-size: 16px;
    cursor: pointer;
    text-decoration: none;
    transition: background 0.3s;
}
.btn:hover {
    background: #2980b9;
}
.alert {
    padding: 15px;
    border-radius: 4px;
    margin-bottom: 20px;
}
.alert-success {
    background: #d4edda;
    border: 1px solid #c3e6cb;
    color: #155724;
}
.alert-error {
    background: #f8d7da;
    border: 1px solid #f5c6cb;
    color: #721c24;
}
.alert-info {
    background: #d1ecf1;
    border: 1px solid #bee5eb;
    color: #0c5460;
}
.alert-warning {
    background: #fff3cd;
    border: 1px solid #ffeeba;
    color: #856404;
}
.qr-container {
    text-align: center;
    margin: 30px 0;
}
.qr-container img {
    border: 2px solid #ddd;
    border-radius: 8px;
    padding: 15px;
    background: white;
}
.secret-box {
    background: #f8f9fa;
    border: 1px solid #dee2e6;
    border-radius: 4px;
    padding: 15px;
    margin: 20px 0;
    font-family: monospace;
    font-size: 18px;
    text-align: center;
    word-break: break-all;
}
.links {
    margin-top: 20px;
    padding-top: 20px;
    border-top: 1px solid #eee;
}
.links a {
    color: #3498db;
    text-decoration: none;
    margin-right: 15px;
}
.links a:hover {
    text-decoration: underline;
}
.logout-link {
    float: right;
    color: #e74c3c;
}
.help-text {
    font-size: 14px;
    color: #666;
    margin-top: 5px;
}
@media (max-width: 600px) {
    .container {
        padding: 10px;
    }
    .card {
        padding: 20px;
    }
}