Global stying fixing

[rainasong]

Description

Currently since different people wrote different files the styling for each page is not quite consistent and does not entirely match the style guide, so really need a global styling fix.

Acceptance Criteria

• [x] Styling across the whole app matches the style guide
• [x] Styling methods are consistent for similar components
• [x] Styling sheets use global variables for font weight, font size etc.
• [x] Remove unnecessary styling code
• [x] Move all stylings to CSS modules if possible
• [x] Dark mode styling is consistent with the style guide

Implementation details

n/a

Testing notes

n/a

[noahjade]

o7 lgtm and goodluck

[rainasong]

o7 lgtm and goodluck

hahaha yea good luck to me😂