jqwidgets-framework/demos/React-TSX/splitter/nestedsplitters/src/App.css

jQWidgets is an advanced Angular, Vue, Blazor, React, Web Components, jquery, ASP .NET MVC, Custom Elements and HTML5 UI framework.

html, body {
  width: 100vw;
  height: 100vh;
  padding: 0;
  margin: 0;
}

.jqx-splitter-nested {
  border: none !important;
}