Accessibility: Check colour palette

[deinhofer]

According to https://davidmathlogic.com/colorblind/#%23D81B60-%231E88E5-%23FFC107-%23004D40 to reflect contrasts and colorblindness.

[sabicalija]

You can use the following link to see the effects on the colors currently used for the website:
https://davidmathlogic.com/colorblind/#%2304303F-%230EA1D2-%23DDE0E5-%23FFFFFF

As mentioned here, I think without 2 different theme colors, there shouldn't be many issues with regards to contrast and colorblindness.

The contrast between the used colors seems as good for people with the most common types of colorblindness as for people able to perceive all colors properly.

The explanations at https://davidmathlogic.com/colorblind/ do mention issues with themes based on green and red. I'm not sure how to interpret this for the used type of blue (#04303F, or #0EA1D2)