Accessibility: Use an accessible 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/#%232C3E50-%23287FA4-%23525C6B-%23FFFFFF

I think it's pretty the same as with asterics-docs (cf. here), as the colors are pretty much the same.

The dark gray which is used at some places seem to differ less from the dark blue with protanopia and deuteranopia (#2C3E50, #525C6B). But both colors are never used in combination for the website. I think there shouldn't be issues with contrast as they only appear in combination with white.

[sabicalija]

I took a detailed look on the contrast ratio. It seems fine (cf. highlighted columns, which represent the contrast ratios of used colors in combination with #ffffff a.k.a. white). The contrast (with white) is actually improved with the most common types of colorblindness.

color-palette.zip

[sabicalija]

There are several extensions for chrome and firefox available, simulating the different types of colorblindness. I have following extension installed: https://chrome.google.com/webstore/detail/spectrum/ofclemegkcmilinpcimpjkfhjfgmhieb

[deinhofer]

the 3rd colour looks very similar to the 1st one, but if it's not used then it does not matter.

There are also some minor contrast problems (the borders and the date/time):

and on the course details page: