Add masonry

Signed-off-by: Nikolaos Karaolidis <nick@karaolidis.com>

assets/sass/gallery.scss

@@ -0,0 +1,45 @@
+.gallery {
+  margin: -0.75rem;
+
+  .grid-sizer {
+    width: calc(25% - 1.5rem);
+    margin: 0 0.75rem;
+  }
+
+  .grid-item {
+    width: calc(25% - 1.5rem);
+    margin: 0.75rem;
+  }
+}
+
+@media (max-width: $width-content) {
+  .gallery {
+    margin: -0.5rem;
+
+    .grid-sizer {
+      width: calc(33% - 1rem);
+      margin: 0 0.5rem;
+    }
+
+    .grid-item {
+      width: calc(33% - 1rem);
+      margin: 0.5rem;
+    }
+  }
+}
+
+@media (max-width: $width-mobile) {
+  .gallery {
+    margin: -0.375rem;
+
+    .grid-sizer {
+      width: calc(50% - 0.75rem);
+      margin: 0 0.375rem;
+    }
+
+    .grid-item {
+      width: calc(50% - 0.75rem);
+      margin: 0.375rem;
+    }
+  }
+}