body {
    background-color: #121212;
    color: #f1f1f1;
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 20px;
    font-size: 20px;
    line-height: 1.6;
    letter-spacing: 0.3px;
}
h1, h2, h3 {
    font-weight: 600;
    margin-bottom: 0.8em;
}
.container {
    max-width: 600px;
    margin: auto;
    padding: 30px;
    background-color: #1a1a1a;
    border-radius: 10px;
    box-shadow: 0 0 20px rgba(0, 0, 0, 0.4);
}
input, select, textarea, button {
    width: 100%;
    padding: 10px;
    margin: 10px 0;
    background: #1e1e1e;
    color: white;
    border: 1px solid #333;
    border-radius: 5px;
}
input, select, textarea {
    transition: border-color 0.3s ease, background-color 0.3s ease;
}
input:focus, select:focus, textarea:focus {
    border-color: #888;
    background-color: #2a2a2a;
    outline: none;
}
button {
    background: #333;
    cursor: pointer;
    font-weight: bold;
    letter-spacing: 0.5px;
    transition: background-color 0.3s ease;
}
button:hover {
    background: #555;
}
model-viewer {
    width: 100%;
    height: 400px;
    margin-top: 20px;
}