Fix Low Contrast Errors

[Rakielle]

Details

As part of openSUSE/mentoring#205, the goal of this issue is to improve the low contrast errors identified by WAVE.

1. Very low contrast between texts and background colours:
WAVE identified sections where the text and background colours have very low contrast. This presents a challenge for users with visual impairments.
According to the WCAG, the minimum recommended contrast ratio for normal text should be 4.5:1. and the contrast ratios of the identified errors fall below this requirement.

This can be fixed by increasing the contrast between the foreground and background colours, while still maintaining Uyuni theme colours.

Reference

Contrast Minimum