问无法将创建的文本框和按钮移动到正确的位置?

EN

function removeElement(e) {
  let button = e.target;
  let field = button.previousSibling;
  let div = button.parentElement;
  let br = button.nextSibling;
  div.removeChild(button);
  div.removeChild(field);
  div.removeChild(br);

  let allElements = document.getElementById("reqs");
  let inputs = allElements.getElementsByTagName("input");
  for (i = 0; i < inputs.length; i++) {
    inputs[i].setAttribute('id', 'reqs' + (i + 1));
    inputs[i].setAttribute('value', (i + 1));
    inputs[i].nextSibling.setAttribute('id', 'reqsr' + (i + 1));
  }
}

function add() {
  let allElements = document.getElementById("reqs");
  let reqs_id = allElements.getElementsByTagName("input").length;

  reqs_id++;

  //create textbox
  let input = document.createElement('input');
  input.type = "text";
  input.setAttribute("class", "w3-input w3-border");
  input.setAttribute('id', 'reqs' + reqs_id);
  input.setAttribute('value', reqs_id);
  let reqs = document.getElementById("reqs");

  //create remove button
  let remove = document.createElement('button');
  remove.setAttribute('id', 'reqsr' + reqs_id);
  remove.onclick = function(e) {
    removeElement(e);
  };
  remove.setAttribute("type", "button");
  remove.innerHTML = "Remove";

  //append elements
  reqs.appendChild(input);
  reqs.appendChild(remove);
  let br = document.createElement("br");
  reqs.appendChild(br);
}

body {
  margin: 0;
  padding: 0;
}

h1 {
  font-family: sans-serif;
  font-size: 16px;
}

input {
  font-family: sans-serif;
  display: inline-block;
  position:relative;
  background-color: #333;
  color: #FFF;
  padding:10px;
}

#reqs {
  width: 100%;
  height: 100%;
  position: relative;
}

.week {
  display:inline-block;
  vertical-align:top;
  width: 49%;
  border: 1px solid grey;
  margin-bottom:2px;
}

.add {
  width: 100%;
  background-color: #eee;
   text-align: center;
}

.add textarea {
  width: 100%;
}

remove {
  width: 100%;
  background-color: #eee;
  text-align: center;
}

button {
  width: 50%;
  background-color: #eee;
  text-align: center;
  padding:7px;
}

<div id="reqs">
  <div class="week week1">
    <div class="add">
      <h1>Weeks</h1>
      <textarea></textarea>
      <button type="button" value="Add" onclick="javascript:add();">Add text</button><br>
    </div>
  </div>
  <div class="week week2">
    <div class="add">
      <h1>Topics</h1>
      <textarea></textarea>
    </div>
  </div>