jupyterlab/packages/htmlviewer/style/base.css

/*-----------------------------------------------------------------------------
| Copyright (c) Jupyter Development Team.
| Distributed under the terms of the Modified BSD License.
|----------------------------------------------------------------------------*/

/* Document styles */
.jp-HTMLViewer {
  overflow: hidden;
}

.jp-HTMLViewer {
  min-width: 100px;
  min-height: 100px;
  width: 100%;
  height: 100%;
}

.jp-HTMLViewer > iframe {
  border: none;
}

/*
When drag events occur, `p-mod-override-cursor` is added to the body.
Because iframes steal all cursor events, the following two rules are necessary
to suppress pointer events while resize drags are occurring. There may be a
better solution to this problem.
*/
body.lm-mod-override-cursor .jp-HTMLViewer {
  position: relative;
}

body.lm-mod-override-cursor .jp-HTMLViewer:before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: transparent;
}