diff --git a/web/src/bundles/common.ts b/web/src/bundles/common.ts
index d8bd988202..06a8119df7 100644
--- a/web/src/bundles/common.ts
+++ b/web/src/bundles/common.ts
@@ -10,6 +10,7 @@ import "../../images/icons/zulip-icons.font";
 import "source-sans/source-sans-3VF.css";
 import "source-code-pro/source-code-pro.css";
 import "@fontsource-variable/open-sans";
+import "../../third/bootstrap/css/bootstrap-alert.css";
 import "../../styles/alerts.css";
 import "../../styles/modal.css";
 import "../../styles/progress_bar.css";
diff --git a/web/third/bootstrap/css/bootstrap-alert.css b/web/third/bootstrap/css/bootstrap-alert.css
new file mode 100644
index 0000000000..9c89327f19
--- /dev/null
+++ b/web/third/bootstrap/css/bootstrap-alert.css
@@ -0,0 +1,52 @@
+/* Bootstrap alert CSS rules that have not been replaced with our own
+   designs. */
+
+.alert {
+  padding: 8px 35px 8px 14px;
+  margin-bottom: 20px;
+  text-shadow: 0 1px 0 rgba(255, 255, 255, 0.5);
+  background-color: #fcf8e3;
+  border: 1px solid #fbeed5;
+  -webkit-border-radius: 4px;
+  -moz-border-radius: 4px;
+  border-radius: 4px;
+}
+.alert,
+.alert h4 {
+  color: #c09853;
+}
+.alert h4 {
+  margin: 0;
+}
+.alert .close {
+  position: relative;
+  top: -2px;
+  right: -21px;
+  line-height: 20px;
+}
+.alert-success {
+  background-color: #dff0d8;
+  border-color: #d6e9c6;
+  color: #468847;
+}
+.alert-success h4 {
+  color: #468847;
+}
+.alert-danger,
+.alert-error {
+  background-color: #f2dede;
+  border-color: #eed3d7;
+  color: #b94a48;
+}
+.alert-danger h4,
+.alert-error h4 {
+  color: #b94a48;
+}
+.alert-info {
+  background-color: #d9edf7;
+  border-color: #bce8f1;
+  color: #3a87ad;
+}
+.alert-info h4 {
+  color: #3a87ad;
+}
diff --git a/web/third/bootstrap/css/bootstrap.app.css b/web/third/bootstrap/css/bootstrap.app.css
index 6cdf7c519a..d56412f70c 100644
--- a/web/third/bootstrap/css/bootstrap.app.css
+++ b/web/third/bootstrap/css/bootstrap.app.css
@@ -293,55 +293,6 @@ input:focus:invalid:focus {
   background-color: transparent;
   cursor: default;
 }
-.alert {
-  padding: 8px 35px 8px 14px;
-  margin-bottom: 20px;
-  text-shadow: 0 1px 0 rgba(255, 255, 255, 0.5);
-  background-color: #fcf8e3;
-  border: 1px solid #fbeed5;
-  -webkit-border-radius: 4px;
-  -moz-border-radius: 4px;
-  border-radius: 4px;
-}
-.alert,
-.alert h4 {
-  color: #c09853;
-}
-.alert h4 {
-  margin: 0;
-}
-.alert .close {
-  position: relative;
-  top: -2px;
-  right: -21px;
-  line-height: 20px;
-}
-.alert-success {
-  background-color: #dff0d8;
-  border-color: #d6e9c6;
-  color: #468847;
-}
-.alert-success h4 {
-  color: #468847;
-}
-.alert-danger,
-.alert-error {
-  background-color: #f2dede;
-  border-color: #eed3d7;
-  color: #b94a48;
-}
-.alert-danger h4,
-.alert-error h4 {
-  color: #b94a48;
-}
-.alert-info {
-  background-color: #d9edf7;
-  border-color: #bce8f1;
-  color: #3a87ad;
-}
-.alert-info h4 {
-  color: #3a87ad;
-}
 .dropdown {
   position: relative;
 }
diff --git a/web/third/bootstrap/css/bootstrap.portico.css b/web/third/bootstrap/css/bootstrap.portico.css
index 6926ff652a..37a42c6528 100644
--- a/web/third/bootstrap/css/bootstrap.portico.css
+++ b/web/third/bootstrap/css/bootstrap.portico.css
@@ -290,55 +290,6 @@ input:focus:invalid:focus {
 .tab-content > .active {
   display: block;
 }
-.alert {
-  padding: 8px 35px 8px 14px;
-  margin-bottom: 20px;
-  text-shadow: 0 1px 0 rgba(255, 255, 255, 0.5);
-  background-color: #fcf8e3;
-  border: 1px solid #fbeed5;
-  -webkit-border-radius: 4px;
-  -moz-border-radius: 4px;
-  border-radius: 4px;
-}
-.alert,
-.alert h4 {
-  color: #c09853;
-}
-.alert h4 {
-  margin: 0;
-}
-.alert .close {
-  position: relative;
-  top: -2px;
-  right: -21px;
-  line-height: 20px;
-}
-.alert-success {
-  background-color: #dff0d8;
-  border-color: #d6e9c6;
-  color: #468847;
-}
-.alert-success h4 {
-  color: #468847;
-}
-.alert-danger,
-.alert-error {
-  background-color: #f2dede;
-  border-color: #eed3d7;
-  color: #b94a48;
-}
-.alert-danger h4,
-.alert-error h4 {
-  color: #b94a48;
-}
-.alert-info {
-  background-color: #d9edf7;
-  border-color: #bce8f1;
-  color: #3a87ad;
-}
-.alert-info h4 {
-  color: #3a87ad;
-}
 .dropdown {
   position: relative;
 }