fix(style): change the background color #746
                
     Merged
            
            
          
  Add this suggestion to a batch that can be applied as a single commit.
  This suggestion is invalid because no changes were made to the code.
  Suggestions cannot be applied while the pull request is closed.
  Suggestions cannot be applied while viewing a subset of changes.
  Only one suggestion per line can be applied in a batch.
  Add this suggestion to a batch that can be applied as a single commit.
  Applying suggestions on deleted lines is not supported.
  You must change the existing code in this line in order to create a valid suggestion.
  Outdated suggestions cannot be applied.
  This suggestion has been applied or marked resolved.
  Suggestions cannot be applied from pending reviews.
  Suggestions cannot be applied on multi-line comments.
  Suggestions cannot be applied while the pull request is queued to merge.
  Suggestion cannot be applied right now. Please check back later.
  
    
  
    
fix #741

Documentation styling updates:
Added custom CSS to override default styles for code blocks and math blocks in
nbsphinx. This ensures proper display of code blocks with a consistent background color and correct alignment of math blocks.Added the
sphinx.ext.mathjaxextension to enable rendering of mathematical expressions in the documentation. Removed a duplicate entry forsphinx.ext.intersphinx.Remove the jupyter notebook output which call the cells are not executable. Thus partially solves Some code blocks are not executing in nbsphinx examples in theme documentation #659