Describe the bug
A clear and concise description of what the bug is.

To Reproduce
Steps to reproduce the behavior:

1. Open sidebar on Desktop
2. Open viewer
3. Change window's width

Expected behavior

1. Viewer right border is on the sidebar border
   

2. When the sidebar's width is changing, viewer width is following the sidebar's border

Actual behavior

1. Viewer overflows the sidebar for 8px
   

2. Sidebar watches the sidebar state change (open/close) but gets the sidebars width only once. When the window is resized
   

Additional info

1. The problem is that viewer doesn't take into account that the sidebar is not on the right border. There is a margin. It is easy to with using var(--body-container-margin). Alternative solution could be to use getBoundingClientRect.

2. It seems, it is fixable using the window's resize event.