CSS Style sheet needs to incorporate css variables

## Problem
The CSS Style sheet lacks css global variables.

## Description

The CSS style sheet does not contain any global variables (which would reduce the work load if any changes are to be made in the future).
This would also be crucial if a dark mode is added to the website, as changing/toggling the stylings would be fairly simple .
This will also help in improving the responsiveness of the website as all necessary attributes can be stored using these variables and can be changed or added any point of time.

## Implementation

- [x] I would be interested in implementing this feature.