White bar at top of viewer

When loading my cesium viewer, by default there is a white bar, about a 1/2" above the viewer.
The Cesium logo and maximize button are below the bottom of the screen.

Here is my current .css section I have:

body, html {
width: 100%;
height: 100%;
margin: 0;
padding: 0;
font-family: Arial, sans-serif;
overflow: hidden; /* This ensures no unexpected scroll bars */

#cesiumContainer {
position: absolute;
width: 100%;
height: 100%;
margin: 0 auto;

I have tried using:
height: calc(100vh - 15px); /* Slightly less than full viewport height */
This raises the logo and maximize button up part way above the bottom

I have searched for any errors in my html file, but at this point, I could be
staring at it for all I know.

Just to reiterate, with height set to 100%, the Cesium logo and maximize button on the right side are below the bottom of the browser screen. If I add back in the calc(100vh-15px), the logo and button come up about a third of their height from the bottom.

Hi pastorjeff. Welcome to the Cesium community.

This is probably a better question for the CesiumJS category. Cesium ion is our software as a service platform for tiling and hosting assets. I’ll move this post to that category.

Is it possible for you to post a link to a Sandcastle that reproduces your problem? It often isn’t possible to know what is going on without seeing all of the code. That will help others understand your problem.