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

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;
    padding: 20px;
    line-height: 1.6;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    background: white;
    border-radius: 12px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    overflow: hidden;
}

header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 40px 30px;
    text-align: center;
}

header h1 {
    font-size: 2.5em;
    margin-bottom: 10px;
}

.subtitle {
    font-size: 1.2em;
    opacity: 0.9;
}

.info-section {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    padding: 30px;
    background: #f8f9fa;
}

.info-card {
    background: white;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.info-card h2 {
    color: #667eea;
    margin-bottom: 15px;
    font-size: 1.4em;
}

.info-card p {
    margin-bottom: 10px;
    color: #555;
}

.link {
    color: #667eea;
    text-decoration: none;
    font-weight: 600;
    display: inline-block;
    margin-top: 10px;
}

.link:hover {
    text-decoration: underline;
}

.video-section {
    padding: 30px;
    background: white;
}

.video-section h2 {
    color: #667eea;
    margin-bottom: 20px;
    font-size: 1.6em;
    text-align: center;
}

.video-container {
    position: relative;
    padding-bottom: 56.25%; /* 16:9 aspect ratio */
    height: 0;
    overflow: hidden;
    max-width: 100%;
    background: #000;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

.video-container iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border-radius: 8px;
}

.alert {
    margin: 20px 30px;
    padding: 15px 20px;
    border-radius: 8px;
    border-left: 4px solid;
}

.alert-error {
    background: #fee;
    border-color: #c33;
    color: #c33;
}

.alert-success {
    background: #efe;
    border-color: #3c3;
    color: #2a2;
}

.download-section {
    margin-top: 15px;
}

.build-section {
    padding: 30px;
}

.build-section h2 {
    color: #333;
    margin-bottom: 20px;
    font-size: 1.8em;
}

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

.form-group label {
    display: block;
    margin-bottom: 8px;
    color: #555;
    font-weight: 600;
}

.form-group select {
    width: 100%;
    padding: 12px;
    border: 2px solid #ddd;
    border-radius: 6px;
    font-size: 1em;
    transition: border-color 0.3s;
}

.form-group select:focus {
    outline: none;
    border-color: #667eea;
}

.btn {
    padding: 14px 28px;
    border: none;
    border-radius: 6px;
    font-size: 1.1em;
    font-weight: 600;
    cursor: pointer;
    text-decoration: none;
    display: inline-block;
    transition: all 0.3s;
}

.btn-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    width: 100%;
}

.btn-primary:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(102, 126, 234, 0.4);
}

.btn-primary:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.btn-download {
    background: #28a745;
    color: white;
}

.btn-download:hover {
    background: #218838;
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(40, 167, 69, 0.4);
}

.building-message {
    margin-top: 30px;
    padding: 30px;
    background: #f8f9fa;
    border-radius: 8px;
    text-align: center;
}

.spinner {
    border: 4px solid #f3f3f3;
    border-top: 4px solid #667eea;
    border-radius: 50%;
    width: 50px;
    height: 50px;
    animation: spin 1s linear infinite;
    margin: 0 auto 20px;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.building-message p {
    color: #555;
    font-size: 1.1em;
    margin-bottom: 10px;
}

.building-message .note {
    font-size: 0.9em;
    color: #888;
}

.warning-section {
    padding: 30px;
    background: #fff3cd;
    border-top: 2px solid #ffc107;
}

.warning-section h3 {
    color: #856404;
    margin-bottom: 15px;
}

.warning-section ul {
    list-style-position: inside;
    color: #856404;
}

.warning-section li {
    margin-bottom: 8px;
}

footer {
    background: #333;
    color: white;
    text-align: center;
    padding: 20px;
}

footer a {
    color: #667eea;
    text-decoration: none;
}

footer a:hover {
    text-decoration: underline;
}

@media (max-width: 768px) {
    .info-section {
        grid-template-columns: 1fr;
    }

    header h1 {
        font-size: 2em;
    }

    .container {
        margin: 10px;
    }
}