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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: #f5f5f5;
    padding: 20px;
}

/* Username Modal Styles */
.modal {
    display: flex;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    align-items: center;
    justify-content: center;
}

.modal-content {
    background-color: white;
    padding: 40px;
    border-radius: 10px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.3);
    max-width: 500px;
    width: 90%;
    text-align: center;
}

.modal-content h2 {
    color: #333;
    margin-bottom: 20px;
}

.modal-content p {
    color: #666;
    margin-bottom: 20px;
}

#username-input {
    width: 100%;
    padding: 12px;
    font-size: 1rem;
    border: 2px solid #ddd;
    border-radius: 6px;
    margin-bottom: 10px;
    transition: border-color 0.2s;
}

#username-input:focus {
    outline: none;
    border-color: #4CAF50;
}

.error-message {
    color: #d32f2f;
    font-size: 0.9rem;
    min-height: 20px;
    margin-bottom: 10px;
}

.modal-btn {
    width: 100%;
    padding: 12px;
    background: #4CAF50;
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 1.1rem;
    font-weight: bold;
    cursor: pointer;
    transition: background 0.2s;
}

.modal-btn:hover {
    background: #45a049;
}

.modal-btn:disabled {
    background: #ccc;
    cursor: not-allowed;
}

/* Main Content Styles */
.container {
    max-width: 1400px;
    margin: 0 auto;
    background: white;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.user-info {
    text-align: right;
    margin-bottom: 20px;
    padding: 10px;
    background: #f0f8f0;
    border-radius: 6px;
    color: #333;
}

.user-info strong {
    color: #4CAF50;
}

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

.models-container {
    display: flex;
    gap: 20px;
    margin-bottom: 40px;
    justify-content: center;
}

.model-viewer {
    flex: 1;
    max-width: 600px;
}

.model-viewer h2 {
    text-align: center;
    color: #666;
    margin-bottom: 15px;
    font-size: 1.2rem;
}

canvas {
    width: 100% !important;
    height: 400px !important;
    border: 2px solid #ddd;
    border-radius: 8px;
    background: #fafafa;
}

.survey-section {
    border-top: 2px solid #eee;
    padding-top: 30px;
}

.question {
    margin-bottom: 30px;
    padding: 20px;
    background: #f9f9f9;
    border-radius: 8px;
}

.question h3 {
    color: #333;
    margin-bottom: 15px;
    font-size: 1.1rem;
}

.choices {
    display: flex;
    flex-direction: row;
    gap: 15px;
    justify-content: center;
    flex-wrap: wrap;
}

.choice {
    display: flex;
    align-items: center;
    padding: 12px 20px;
    background: white;
    border: 2px solid #ddd;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.2s;
    flex: 0 1 auto;
}

.choice:hover {
    border-color: #4CAF50;
    background: #f0f8f0;
}

.choice input[type="radio"] {
    margin-right: 10px;
    cursor: pointer;
}

.submit-btn {
    display: block;
    width: 200px;
    margin: 30px auto 0;
    padding: 15px;
    background: #4CAF50;
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 1.1rem;
    font-weight: bold;
    cursor: pointer;
    transition: background 0.2s;
}

.submit-btn:hover {
    background: #45a049;
}

.submit-btn:disabled {
    background: #ccc;
    cursor: not-allowed;
}

.message {
    text-align: center;
    padding: 15px;
    margin: 20px 0;
    border-radius: 6px;
    display: none;
}

.message.success {
    background: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
    display: block;
}

.message.error {
    background: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
    display: block;
}