Can I add CSS to Just Portfolio Pages? (And not rest of site)

Hi – long time Enfold user, but not a code warrior.

I have a need to make sure my slide shows in my Portfolio pages ONLY will keep the original dimensions of the images I uploaded. I am using Easy Slider for the slide show. The problem was the horizontal oriented slides worked great, but the vertically oriented slides got stretched and enlarged.

Potential fix: I found some code here that worked and the Portfolio pages worked great- but it worked globally on ALL slide show images… so my Full Width Slider Images do not stretch anymore – the code I used was:

.avia-slideshow li img {
width: auto;

How can I add this code for JUST my Portfolio pages? Do I have to add code to each of my 9 pages – or can I do it globally. I still want my other full width slide show graphics to stretch all the way (and not stop)

Thank you all.