code: function handleDocumentMousedown(e) {
    let svg;
    if (_type !== 'area' || !(svg = findSVGAtPoint(e.clientX, e.clientY))) {
      return;
    }
  
    let rect = svg.getBoundingClientRect();
    originY = e.clientY;
    originX = e.clientX;
  
    overlay = document.createElement('div');
    overlay.style.position = 'absolute';
    overlay.style.top = `${originY - rect.top}px`;
    overlay.style.left = `${originX - rect.left}px`;
    overlay.style.border = `3px solid ${BORDER_COLOR}`;
    overlay.style.borderRadius = '3px';
    svg.parentNode.appendChild(overlay);
    
    document.addEventListener('mousemove', handleDocumentMousemove);
    disableUserSelect();
  }
docs: Handle document.mousedown event
  
  @param {Event} e The DOM event to handle