ant-design-vue/components/table/style/resize.less

.@{table-prefix-cls}-resize-handle {
  position: absolute;
  top: 0;
  height: 100% !important;
  bottom: 0;
  left: auto !important;
  right: -8px;
  cursor: col-resize;
  touch-action: none;
  user-select: auto;
  width: 16px;
  z-index: 1;
  &-line {
    display: block;
    width: 1px;
    margin-left: 7px;
    height: 100% !important;
    background-color: @primary-color;
    opacity: 0;
  }
  &:hover &-line {
    opacity: 1;
  }
}

.@{table-prefix-cls}-resize-handle.dragging {
  overflow: hidden;
  .@{table-prefix-cls}-resize-handle-line {
    opacity: 1;
  }
  &:before {
    position: absolute;
    top: 0;
    bottom: 0;
    width: 100%;
    content: ' ';
    width: 200vw;
    transform: translateX(-50%);
    opacity: 0;
  }
}