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

[hidden] { display: none !important; }

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

.container {
    background: white;
    border-radius: 12px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    max-width: 600px;
    width: 100%;
    padding: 40px;
}

h1 { color: #333; margin-bottom: 30px; text-align: center; font-size: 28px; }

.topbar { display: flex; align-items: center; justify-content: space-between; margin-bottom: 30px; }
.topbar h1 { margin: 0; text-align: left; }

.form-group { margin-bottom: 20px; }

label { display: block; margin-bottom: 8px; color: #555; font-weight: 500; font-size: 14px; }

input {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    font-size: 15px;
    transition: border-color 0.3s;
    font-family: inherit;
}
input:focus { outline: none; border-color: #667eea; }
input.invalid { border-color: #e74c3c; }

button {
    width: 100%;
    padding: 14px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
}
button:hover { transform: translateY(-2px); box-shadow: 0 8px 20px rgba(102, 126, 234, 0.4); }
button:active { transform: translateY(0); }
button:disabled { opacity: 0.6; cursor: not-allowed; transform: none; }

button.link {
    width: auto;
    padding: 6px 12px;
    background: none;
    color: #667eea;
    font-size: 14px;
    font-weight: 500;
    border: 1px solid #667eea;
}
button.link:hover { transform: none; box-shadow: none; background: #f0f2ff; }

.message {
    margin-top: 20px;
    padding: 12px;
    border-radius: 8px;
    text-align: center;
    font-weight: 500;
    display: none;
}
.message.success { background: #d4edda; color: #155724; border: 1px solid #c3e6cb; }
.message.error { background: #f8d7da; color: #721c24; border: 1px solid #f5c6cb; }
.message.show { display: block; }

.required { color: #e74c3c; }

#responseBox {
    margin-top: 20px;
    padding: 14px;
    background: #f8f9fa;
    border-radius: 8px;
    overflow: auto;
    white-space: pre-wrap;
    font-size: 13px;
}