remove PhotoSwipe (AdvisorySG#198)

* remove HBS, CSS and JS references to PhotoSwipe
* use ghost's default assets for .kg components

assets/css/misc/kg.css

@@ -1,6 +1,22 @@
+.kg-gallery-card,
+.kg-gallery-card * {
+    box-sizing: border-box;
+}
+
+.kg-gallery-card,
+.kg-image-card {
+    --gap: 1.2rem;
+}
+
+.kg-image-card:not(.kg-card-hascaption) + .kg-image-card,
+.kg-image-card:not(.kg-card-hascaption) + .kg-gallery-card,
+.kg-gallery-card:not(.kg-card-hascaption) + .kg-image-card,
+.kg-gallery-card:not(.kg-card-hascaption) + .kg-gallery-card {
+    margin-top: var(--gap);
+}
+
 .kg-gallery-container {
-    display: flex;
-    flex-direction: column;
+    position: relative;
 }
 
 .kg-gallery-row {
@@ -9,21 +25,26 @@
     justify-content: center;
 }
 
-.kg-gallery-image {
-    cursor: pointer;
-}
-
 .kg-gallery-image img {
+    display: block;
+    margin: 0;
     width: 100%;
     height: 100%;
 }
 
 .kg-gallery-row:not(:first-of-type) {
-    margin: 10px 0 0;
+    margin: var(--gap) 0 0;
 }
 
 .kg-gallery-image:not(:first-of-type) {
-    margin: 0 0 0 10px;
+    margin: 0 0 0 var(--gap);
+}
+
+@media (max-width: 600px) {
+    .kg-gallery-card,
+    .kg-image-card {
+        --gap: 0.6rem;
+    }
 }
 
 .kg-bookmark-card {

assets/css/screen.css

@@ -31,7 +31,6 @@
 @import "members/auth.css";
 @import "members/account.css";
 @import "members/notification.css";
-@import "vendor/pswp.css";
 @import "misc/lazyload.css";
 @import "misc/kg.css";
 @import "misc/utils.css";