.viewport-tabs{display:flex;gap:5px;margin-bottom:15px;flex-wrap:wrap}
.tab-btn{padding:6px 12px;border:1px solid #ddd;background:#f8f9fa;cursor:pointer;font-size:13px}
.tab-btn.active{background:#3592e2;color:#fff;border-color:#3592e2}
.preview-container{text-align:center;border:1px solid #ddd;border-radius:4px;padding:10px;background:#f0f0f0;overflow:auto}
#previewFrame{border:none;background:#fff;width:375px;height:500px;transition:width .3s}
.width-label{margin-top:8px;font-size:13px;color:#666}