change color to just one page?

thanks i can now edit but its not changing color of the page.

i went to menus then top menu then selected the menu item i want to change the page color for, on Page Display Options i put mysuffix i also tried "mysuffix" in the Page Class text box i then went to template_css.css and i put the code at the very bottom and also tried it in the middle.

.mysuffix p{
color:yellow
}

also tried
.mysuffix p{
color:#000000
}

etc nothing worked

and ; ?

.mysuffix p{
color:yellow;
}

.mysuffix p{
color:#000000;
}

also is you just made mistake writing post you can use !important flag:

.mysuffix p{
color:yellow!important;
}