add lightbox for post image previews

sass/style.scss

@@ -220,7 +220,7 @@ pre code {
   font-size: 1rem;
 }
 
-#delete-dialog {
+#delete-dialog, .lightbox-dialog {
   padding: 0;
   border-radius: 4px;
   border: 2px solid black;
@@ -234,6 +234,27 @@ pre code {
   padding: 20px;
 }
 
+.lightbox-inner {
+  display: flex;
+  flex-direction: column;
+  padding: 20px;
+  min-width: 400px;
+  background-color: $accent_color;
+  gap: 10px;
+}
+
+.lightbox-image {
+  max-width: 70vw;
+  max-height: 70vh;
+  object-fit: scale-down;
+}
+
+.lightbox-nav {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+}
+
 .copy-code-container {
   position: sticky;
   // width: 100%;