Styling SideBar

Good afternoon,

I have searched this site to the very end and i was not able to get any tips on the problems bugging my mind.

1. If you look at https://www.kineda.com, you would notice that the background color of each post is different from the whole index page. i dont know how to do that

2. looking at https://www.darrenhoyt.com/, the menu on the left is colored in blue. i would want to know if i can style each side bar column (or widget) to be in a different color.

3. also on https://www.darrenhoyt.com/, i want to know how he did the drop-down list on the right. if you hover on the categories menu, it brings out a dropbox automatically

4. https://www.darrenhoyt.com/ again. how did he manage to style the title of the categories in the home page..for example where he has popularpost, popular and post has a different color/font.

Please i hope i was clear and i would want to thank you in advance.

Thanks