.page-container {
    margin: 20px;
}
  
  
/* horizontal panel*/
  
.panel-container {
    display: flex;
    flex-direction: row;
    border: 1px solid silver;
    overflow: hidden;
    scroll-padding-right: unset;
    /* avoid browser level touch actions */
    xtouch-action: none;
}

.panel-left {
    flex: 0 0 auto;
    /* only manually resize */
    padding: 10px;
    width: 300px;
    overflow: hidden;
    min-height: 700px;
    min-width: 100px;
    white-space: nowrap;
    background: whitesmoke;
}
  
.splitter {
    flex: 0 0 auto;
    width: 8px;  
    background: url(https://raw.githubusercontent.com/RickStrahl/jquery-resizable/master/assets/vsizegrip.png) center center no-repeat #535353;
    min-height: 200px;  
}
  
.panel-right {
    flex: 1 1 auto;
    /* resizable */
    padding: 10px;
    width: 100%;
    min-height: 200px;
    min-width: 200px;
    background: whitesmoke;;
}