fix(post): fix the size of embedded YouTube videos.

src/app/post/components/post-details/post-details.component.scss

@@ -47,6 +47,7 @@ h1 {
 }
 
 .description {
+  position: relative;
   a {
     font-size: $font-size-small;
     color: $red;
@@ -64,11 +65,6 @@ h1 {
   ::ng-deep img {
     height: 100%;
   }
-  ::ng-deep iframe {
-    width: 100% !important;
-    max-height: 400px;
-    height: 100vw;
-  }
   ::ng-deep .kg-embed-card {
     max-height: 400px;
     iframe {
@@ -83,4 +79,9 @@ h1 {
       text-align: center;
     }
   }
+  iframe {
+    position: relative;
+    width: 100%;
+    height: 400px;
+  }
 }