CSS/HTML integration

programming web dev
1

Is CSS limited to styles, or can I do more with it? Can I arrange images? can I insert javascript and other codes? Here is what I found on HTMLDog.

body {
    font-family: arial, helvetica, sans-serif;
    font-size: 80%;
    color: black;
    background-color: #ffc;
    margin: 1em;
    padding: 0;
}

Can I add anything?

Edit: Other than headers and such. I mean within a section…

Thanks in advance:)

~Haven

PS. feel free to pm me!