Readapt the misuse of BEM, Code organization

- -- is only for a modifier, not a child "child". Use master__child without the parent__ in it to make it more readable.
https://www.smashingmagazine.com/2016/06/battling-bem-extended-edition-common-problems-and-how-to-avoid-them/
- Redefine atom design components

src/style/pages/_homepage.scss

@@ -50,7 +50,7 @@
         }
 
         // Photos
-        .gallery__images--photo {
+        .gallery__photo {
             &:before {
                 background-color: $color-secondary;
             }