The FutureLearn colour palette is taken from the FutureLearn gradient, which symbolises the journey from past to present to future.
When using these colours in stylesheets, use the SCSS colour mixin to reference the colour by name rather than referencing the hex code directly.
Some colours work from well together, while others don’t. In general, avoid combining bright primary colours, as it may look garish and heavy for the eye.
Below are the greyscale combinations that provide enough contrast to be accessible. If the colours you're using are not in this grid, you can check the contrast using this contrast ratio tool.