When styling pages and working with the representational aspect of your project, I have found these two resources to be extremely helpful for learning the basics and some tips & tricks for implementing cool styles into your project.
The first is FlexBox Froggy — check it out here!
An interactive game that teaches you the basics to flexbox styling and some cool tips to help remember when to apply these rules.
The other is CSS Zen Garden — check it out here!
This website publishes other users web pages and allows the users to download the CSS styles sheets to see how it was created. A perfect way to find inspiration and features to implement into your next project.