Update The CentOS Symbol design models used inside documentation
    manuals.
    
        - Start using `888888ff' color as grid background.
    
        - Enumerate steps on bottom description area.
    
        - Start using `000000ff' color as bottom description background
          and border lines.
    
        - Change quotation typography from `Sans'  to `Monospace' on
          symbol construction.
    
        - Add the hexadecimal color codes of symbol construction, in both
          squares and arrows.