Wells: How can I change text weights ("boldness") for title of image captions in galleries

I am using a Wells template and am trying to change the level of "boldness" of the image captions in my image galleries. What Custom CSS code snipets work? I managed to  change the font weight for the image description but same code does not work for the image title. Font I am using is  "LATO"

.image-title {
         font-size: 17px;
         letter-spacing: 0.02em;
           font-weight: 400;  "this does not work"
}
.image-desc p {
               font-size: 16px;   font-weight: 400; "this works" 
 }

Link to your page please.