fix: embed pdf aspect ratio (closes #1310)

quartz/plugins/transformers/ofm.ts

@@ -263,7 +263,7 @@ export const ObsidianFlavoredMarkdown: QuartzTransformerPlugin<Partial<Options>
                   } else if ([".pdf"].includes(ext)) {
                     return {
                       type: "html",
-                      value: `<iframe src="${url}"></iframe>`,
+                      value: `<iframe src="${url}" class="pdf"></iframe>`,
                     }
                   } else {
                     const block = anchor

quartz/styles/base.scss

@@ -542,7 +542,8 @@ ol.overflow {
   overflow-y: hidden;
 }
 
-.external-embed.youtube {
+.external-embed.youtube,
+iframe.pdf {
   aspect-ratio: 16 / 9;
   height: 100%;
   width: 100%;