:root {
  --box-width: 200px;
}

body {
  margin: 40px;
}

.wrapper {
  background-color: #fff;
  color: #444;
  display: flex;
}

.box {
  background-color: #444;
  color: #fff;
  border-radius: 5px;
  padding: 20px;
  font-size: 12px;

  box-sizing: border-box;

  flex: 1 1 auto;
}

.handler {
  width: 20px;
  padding: 0;
  cursor: ew-resize;
  flex: 0 0 auto;
}

.handler::before {
  content: "";
  display: block;
  width: 2px;
  height: calc(100vh - 34px);
  background: #c0c0c0;
  margin: 0 auto;
}

.arrowButton {
  display: flex;
  justify-content: flex-end;
  /* transition: 0.4s; */
  width: 100%;
}

.verticalText {
  display: flex;
  flex-direction: column;
  justify-content: center;
  writing-mode: vertical-lr;
  text-orientation: mixed;
  transform: rotate(180deg);
  font-size: 1.3rem;
}

.leftWrapper {
  background-color: #fff;
  color: black;
  border-radius: 5px;
  padding: 0rem 0.5rem;
  font-size: 12px;
  box-sizing: border-box;
  flex: 1 1 auto;
  min-width: var(--box-width);
  flex-grow: 0;
}

.rightWrapper {
  background-color: #fff;
  color: black;
  border-radius: 5px;
  padding: 0rem 0.5rem;
  font-size: 12px;
  box-sizing: border-box;
  flex: 1 1 auto;
  min-width: var(--box-width);
  flex-grow: 1;
}