Customizing the different template section seperatly

Hi, im using the Marquee template as base, and im now customizing it so it will wit my site structure. My problem is that when i make one CSS change, it applies to all the sections of the page, not just the one im trying to edit.

My first code is:

.homepage .page-desc p:nth-child(1) { font-family: proxima-nova; font-weight:bold; font-size: 100px; } .homepage h1.page-title:nth-child(1) { color: #d3d3d3; }

This is for customizing the homepage/index title and description. However, this edits the title and description of all the pages.

My question is, how can i edit each section separately?

Thanks for feedback