css() method won't take hex

Hi Everyone,

I noticed that when I try to use a hex color value such as #ff0000 that it won't pass the test. However, if I use rgb() it will pass the text. For example:
expect($('div')).to.have.css('color', '#ff0000'); ---> will NOT pass
expect($('div')).to.have.css('color', 'rgb(255, 0, 0)');" --> WILL pass

I am writing the tests in the following json doc:
https://github.com/BlueOceanView/freecodecamp/blob/master/seed_data/coursewares.json#L78

I am wondering why this is so?

Thanks!
Julie (a.k.a. BlueOceanView)