.preview {
    position: fixed;
    right: 0px;
    width:50%;
    height: 100%;
    border: none;
    border-left: solid 1px gray;
}

.preview-splitter {
    position: absolute;
    height:100%;
    width:10px;
    margin-left:-5px;
    background: transparent;
    z-index:80
}
.preview-splitter:hover {
    cursor: col-resize;
}