.gallery-sticky { position: sticky; top: 20px; z-index: 10; }
    
    .main-photo-frame {
        background: #fff;
        border-radius: 20px;
        padding: 40px;
        text-align: center;
        border: 1px solid #f0f0f0;
        margin-bottom: 20px;
        box-shadow: 0 20px 40px rgba(0,0,0,0.05);
        height: 600px; 
        display: flex;
        align-items: center;
        justify-content: center;
        position: relative;
        overflow: hidden;
    }
    .main-photo-frame img { width: 100%; height: 100%; object-fit: contain; max-width: 450px; transition: opacity 0.3s; }
    
    .selected-device-preview {
        position: absolute;
        bottom: 20px;
        right: 20px;
        width: 130px;
        height: 130px;
        background: #fff;
        border: 1px solid #e1e1e1;
        border-radius: 16px;
        padding: 10px;
        display: none;
        flex-direction: column;
        align-items: center;
        justify-content: center;
        box-shadow: 0 10px 40px rgba(0,0,0,0.12);
        z-index: 20;
        animation: popIn 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    }
    @keyframes popIn { from { transform: scale(0.8); opacity: 0; } to { transform: scale(1); opacity: 1; } }
    
    .selected-device-preview img { width: 100%; height: 80px; object-fit: contain; margin-bottom: 8px; }
    .selected-device-preview span { font-size: 10px; font-weight: 800; color: #0056b3; text-transform: uppercase; letter-spacing: 0.5px; }

    .thumbs-row { display: flex; gap: 15px; justify-content: center; }
    .thumb-btn { width: 80px; height: 80px; border-radius: 12px; border: 2px solid transparent; cursor: pointer; padding: 5px; background: #f9f9f9; transition: 0.2s; }
    .thumb-btn.active, .thumb-btn:hover { border-color: var(--tyent-blue); background: #fff; }
    .thumb-btn img { width: 100%; height: 100%; object-fit: contain; border-radius: 6px;}

    .replace-section { padding: 60px 0 100px 0; background: #fff; font-family: 'Manrope', sans-serif; text-align: center;}

    .replace-container { max-width: 1000px; margin: 0 auto; padding: 0 20px; }

    .replace-title { font-size: 28px; font-weight: 800; color: #111; margin-bottom: 40px; }

    .steps-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 30px; }

    .step-card { background: #f9f9fb; padding: 30px 20px; border-radius: 16px; border: 1px solid #eee; position: relative; }

    .step-num { width: 40px; height: 40px; background: #0056b3; color: #fff; font-size: 18px; font-weight: 800; border-radius: 50%; display: flex; align-items: center; justify-content: center; margin: 0 auto 20px auto; }

    .step-card h4 { font-size: 18px; font-weight: 700; color: #111; margin-bottom: 10px; }

    .step-card p { font-size: 14px; color: #555; line-height: 1.5; margin: 0; }

    @media (max-width: 768px) { .steps-grid { grid-template-columns: 1fr; gap: 20px; } }