If your CSS file is compressed into a single line and all the indentation that made reading easier is lost, you can use the Online CSS Unminifier – http://mrcoles.com/blog/css-unminify/.
The same tool for Javascript – http://jsbeautifier.org/.
If you want to quickly find out what color codes your page consists of, to change a particular color, and if you don’t know the RGB codes by heart, HexTractor is a good tool – https://hex.corvidworks.com/.
For working with RGBA codes – http://www.w3schools.com/cssref/tryit.asp?filename=trycss_color_rgba.