Customized CSS Questions

Hello again Sakin. I just really wanted to learn more about this thing. What will be my guide if I wanted to customize any parts of the theme? Where will I get the right "word" so I can make it the result that I wanted it to come out? Like this one: #main a.title:hover { color: #f9854a; } That is wrong because I cannot find the right word to call to make it the way I wanted it to be. "I wanted the title of the content when hovered over to change to that color.." Does every theme has different "words" to customized it?   Thank you!