@media (min-width: 900px) {
  .split {
    display: grid;
    grid-template-columns: 1fr 4px 1fr;
    grid-template-rows: 1fr;
    flex: 1;
    min-height: 0;
    overflow: hidden;
  }
  
  .pane {
    border-bottom: none;
    overflow: hidden;
    min-width: 0;
    min-height: 0;
  }
  
  #editorPane {
    grid-column: 1;
    border-right: none;
  }
  
  .resizer {
    grid-column: 2;
  }
  
  #viewerPane {
    grid-column: 3;
  }
  
  .tabs {
    display: none;
  }
  
  body[data-page="editor"] #viewerPane,
  body[data-page="viewer"] #editorPane {
    display: flex !important;
  }
  
  .expandBtn {
    display: flex; /* Hiển thị trên PC */
    align-items: center;
    justify-content: center;
  }
  
  /* Override mobile display rules on PC */
  #editorPane,
  #viewerPane {
    display: flex !important;
  }
  
  /* When expanded, hide the other pane */
  .split[style*="grid-template-columns: 1fr 4px 0fr"] #viewerPane,
  .split[style*="grid-template-columns: 0fr 4px 1fr"] #editorPane {
    display: none !important;
  }
  
  /* Resizer */
  .resizer {
    display: block;
    width: 4px;
    background: var(--border);
    cursor: col-resize;
    position: relative;
    flex-shrink: 0;
  }
  
  .resizer:hover {
    background: var(--accent);
  }
  
  .resizer::before {
    content: '';
    position: absolute;
    left: -4px;
    right: -4px;
    top: 0;
    bottom: 0;
    cursor: col-resize;
  }
  
  /* Active resizing state */
  body[style*="cursor: col-resize"] .resizer {
    background: var(--accent);
  }
}