diff --git a/app/assets/stylesheets/common/base/topic-post.scss b/app/assets/stylesheets/common/base/topic-post.scss
index dc3f1625dd0..0d86f038fd5 100644
--- a/app/assets/stylesheets/common/base/topic-post.scss
+++ b/app/assets/stylesheets/common/base/topic-post.scss
@@ -705,6 +705,7 @@ blockquote > *:last-child {
     font-weight: bold;
     font-size: $font-down-1;
     color: $primary-medium;
+    min-width: 0; // Allows flex container to shrink
 
     .custom-message {
       flex: 1 1 100%;
@@ -712,6 +713,8 @@ blockquote > *:last-child {
       font-weight: normal;
       font-size: $font-up-1;
       order: 12;
+      word-break: break-word;
+      min-width: 0; // Allows content like oneboxes to shrink
       p {
         margin-bottom: 0;
       }