问从右边的固定位置调整元素大小的问题

EN

#resize {
  position: fixed;
  right: 30px;
  left: calc(100% - 120px);
  height: 90px;
  width: 90px;
  background-color: blue;
  resize: both;
  overflow: auto;
  min-width: 90px;
  min-height: 90px;
  max-width: calc(100% - 60px);
  max-height: calc(100vh - 50px);
}

dragElement(document.getElementById("resize"));

function dragElement(elmnt) {
  var pos1 = 0,
    pos2 = 0,
    pos3 = 0,
    pos4 = 0;
  if (document.getElementById("drag")) {
    document.getElementById("drag").onmousedown = dragMouseDown;
  } else {
    elmnt.onmousedown = dragMouseDown;
  }

  function dragMouseDown(e) {
    e = e || window.event;
    e.preventDefault();
    pos3 = e.clientX;
    pos4 = e.clientY;
    document.onmouseup = closeDragElement;
    document.onmousemove = elementDrag;
  }

  function elementDrag(e) {
    e = e || window.event;
    e.preventDefault();
    pos1 = pos3 - e.clientX;
    pos2 = pos4 - e.clientY;
    pos3 = e.clientX;
    pos4 = e.clientY;
    elmnt.style.top = (elmnt.offsetTop - pos2) + "px";
    elmnt.style.left = (elmnt.offsetLeft - pos1) + "px";
  }

  function closeDragElement() {
    document.onmouseup = null;
    document.onmousemove = null;
  }
}

#resize {
  position: fixed;
  right: 30px;
  height: 90px;
  width: 90px;
  background-color: blue;
  resize: both;
  overflow: auto;
  min-width: 90px;
  min-height: 90px;
  max-width: calc(100% - 60px);
  max-height: calc(100vh - 50px);
}

#drag {
  background-color: red;
  height: 20px;
}

<div id="resize">
  <div id="drag">
  </div>
</div>