import Split from 'split.js'

Split(['#split-0', '#split-1'])

<div class="split">
    <div id="split-0"></div>
    <div id="split-1"></div>
</div>

.split {
    display: flex;
    flex-direction: row;
}

.gutter {
    background-color: #eee;
    background-repeat: no-repeat;
    background-position: 50%;
}

.gutter.gutter-horizontal {
    background-image: url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUAAAAeCAYAAADkftS9AAAAIklEQVQoU2M4c+bMfxAGAgYYmwGrIIiDjrELjpo5aiZeMwF+yNnOs5KSvgAAAABJRU5ErkJggg==');
    cursor: col-resize;
}