How to correctly lay out a wireframe with position: fixed?

Question

css

Tell me, please, how can I make a frame for the Admin panel of the site if I need the panel on the left and the top menu to be fixed by pressing it with position: fixed?
When I use position: fixed, the content goes under the panel on the left. There is no more flow. And I would like to keep adaptability to different resolutions.
How to correctly specify the place for the content using css, and how is this solved in practice?

Answer 1

For the body, set padding-left to the width of the sidebar and padding-top to the height of the top