In the dropdown menu, Format->Conditional formatting...
Then set your rules and your color. You can select multiple cells and do this also.
Edit:
That is the extent of what you can do with coloring. You can maybe find a complex formula to find the minimum of the cells, and then if that matches what is in the cell, then color it, but you may want to use Excel instead of Google docs if this is a critical thing for you.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…