Change color of <th>'s border-bottom elements in markdown content

Author: hugo19941994

src/style/_layout.scss

@@ -579,6 +579,7 @@
         th
         {
             @include text_code($response-col-description-inner-markdown-font-color);
+            border-bottom: 1px solid $response-col-description-inner-markdown-font-color;
         }
     }
 }