body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    margin: 0;
    padding: 0;
    background-color: #f4f7f6;
    color: #333;
    display: flex;
    justify-content: center;
    align-items: flex-start; /* Align to top for scroll */
    min-height: 100vh;
    padding-top: 20px; 
    padding-bottom: 20px; 
}

.prototype-container {
    background-color: #fff;
    width: 90%;
    max-width: 960px;
    margin: 20px auto;
    padding: 25px;
    border-radius: 10px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

header {
    text-align: center;
    margin-bottom: 25px;
    padding-bottom: 15px;
    border-bottom: 2px solid #e0e0e0;
}

header h1 {
    color: #2c3e50;
    font-size: 2em;
    font-weight: 600;
}

.tabs {
    display: flex;
    border-bottom: 2px solid #e0e0e0;
    margin-bottom: 20px;
}

.tab-link {
    background-color: transparent;
    border: none;
    outline: none;
    cursor: pointer;
    padding: 14px 20px;
    font-size: 1em;
    font-weight: 500;
    color: #555;
    transition: color 0.3s ease, border-bottom 0.3s ease;
    border-bottom: 3px solid transparent;
}

.tab-link:hover {
    color: #667eea;
}

.tab-link.active {
    color: #667eea;
    border-bottom: 3px solid #667eea;
    font-weight: 600;
}

.tab-content {
    display: none;
    padding: 10px 5px;
    animation: fadeIn 0.5s;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.tab-content h2 {
    color: #34495e;
    margin-top: 0;
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 1px solid #ecf0f1;
}

.tab-content section {
    margin-bottom: 25px;
}

.tab-content section h3 {
    color: #34495e;
    margin-bottom: 10px;
    font-size: 1.3em;
}

.tab-content ul, .tab-content ol {
    margin-left: 20px;
    padding-left: 15px;
}

.tab-content li {
    margin-bottom: 8px;
    color: #555;
}

/* Styles for Application Mockup */
.mockup-app-container {
    border: 1px solid #ccc;
    padding: 20px;
    border-radius: 8px;
    background-color: #f9f9f9;
}

.mockup-main-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    margin-bottom: 20px;
}

.mockup-panel {
    border: 1px solid #ddd;
    border-radius: 8px;
    padding: 20px;
    background-color: #fff;
    box-shadow: 0 2px 5px rgba(0,0,0,0.05);
}

.mockup-panel h3 {
    margin-top: 0;
    margin-bottom: 15px;
    font-size: 1.2em;
    color: #333;
    display: flex;
    align-items: center;
    gap: 8px;
}

.mockup-icon {
    font-size: 1.1em;
    color: #667eea;
}

.mockup-upload-zone {
    border: 2px dashed #667eea;
    border-radius: 8px;
    padding: 25px;
    text-align: center;
    background-color: #f0f4ff;
    margin-bottom: 15px;
}

.mockup-upload-zone h4 {
    margin: 10px 0 5px 0;
    color: #333;
}
.mockup-upload-icon {
    font-size: 2.5em;
    display: block;
    margin-bottom: 10px;
    color: #667eea;
}

.mockup-small-text {
    font-size: 0.85em;
    color: #555;
}

.mockup-btn {
    background: linear-gradient(45deg, #667eea, #764ba2);
    color: white;
    border: none;
    padding: 10px 18px;
    border-radius: 6px;
    cursor: default; /* Not interactive */
    font-size: 0.95em;
    margin-right: 8px;
    margin-bottom: 8px;
    transition: opacity 0.2s;
}
.mockup-btn:hover {
    opacity: 0.9;
}

.mockup-btn-secondary {
    background: linear-gradient(45deg, #6c757d, #495057);
}

.mockup-progress-bar {
    width: 100%;
    height: 10px;
    background-color: #e9ecef;
    border-radius: 5px;
    margin-top: 20px;
    overflow: hidden;
}

.mockup-progress-fill {
    height: 100%;
    background: linear-gradient(45deg, #667eea, #764ba2);
    border-radius: 5px;
}

.mockup-settings-grid {
    display: grid;
    grid-template-columns: 1fr; /* Simpler for mockup */
    gap: 10px;
}

.mockup-setting-item {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px;
    background: #f8f9fa;
    border-radius: 5px;
    border: 1px solid #eee;
}

.mockup-setting-item input[type="checkbox"] {
    transform: scale(1.1);
    accent-color: #667eea;
    cursor: default;
}
.mockup-setting-item label {
    font-size: 0.9em;
    color: #444;
}

.mockup-preview-area {
    border: 1px solid #ddd;
    border-radius: 8px;
    padding: 0; /* Remove padding to make tabs flush */
    margin-bottom: 20px;
    background-color: #fff;
    box-shadow: 0 2px 5px rgba(0,0,0,0.05);
}

.mockup-preview-tabs {
    display: flex;
    border-bottom: 1px solid #ddd;
    background-color: #f8f9fa;
    border-top-left-radius: 8px;
    border-top-right-radius: 8px;
}

.mockup-tab {
    padding: 12px 20px;
    cursor: default;
    color: #555;
    border-bottom: 3px solid transparent;
    font-weight: 500;
    transition: color 0.2s, border-bottom-color 0.2s;
}

.mockup-tab.active {
    color: #667eea;
    border-bottom-color: #667eea;
    font-weight: 600;
}

.mockup-preview-content {
    padding: 20px;
    min-height: 150px;
}
.mockup-preview-content h4 {
    margin-top: 0;
    margin-bottom: 10px;
    color: #333;
}

.mockup-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9em;
    margin-top: 15px;
}

.mockup-table th, .mockup-table td {
    border: 1px solid #e0e0e0;
    padding: 8px 10px;
    text-align: left;
}
.mockup-table th {
    background-color: #f0f2f5;
    font-weight: 600;
}
.mockup-table td {
    background-color: #fff;
}
.mockup-table tbody tr:nth-child(even) td {
    background-color: #f8f9fa;
}

.mockup-log-area {
    border: 1px solid #ddd;
    border-radius: 8px;
    padding: 15px;
    background-color: #2c3e50; 
    color: #e0e0e0; 
    font-family: 'Courier New', Courier, monospace;
    font-size: 0.9em;
    min-height: 100px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.05);
}
.mockup-log-area p {
    margin: 0 0 6px 0;
}
.mockup-log-area p::before {
    content: "> ";
    opacity: 0.7;
}


@media (max-width: 768px) {
    .prototype-container {
        width: 95%;
        padding: 15px;
    }

    header h1 {
        font-size: 1.8em;
    }

    .tabs {
        flex-direction: column;
    }

    .tab-link {
        width: 100%;
        text-align: left;
        border-bottom: 1px solid #eee; /* For non-active tabs on mobile */
    }
    .tab-link.active {
         border-bottom: 3px solid #667eea; /* Keep for active tab */
    }

    .mockup-main-grid {
        grid-template-columns: 1fr; /* Stack panels on smaller screens */
    }
     .mockup-panel h3 {
        font-size: 1.1em;
    }
    .mockup-btn {
        padding: 9px 15px;
        font-size: 0.9em;
    }
}