diff --git a/app/src/main/java/io/heckel/ntfy/ui/TrustedCertificateFragment.kt b/app/src/main/java/io/heckel/ntfy/ui/TrustedCertificateFragment.kt
index 53be0e84..ac2bdeec 100644
--- a/app/src/main/java/io/heckel/ntfy/ui/TrustedCertificateFragment.kt
+++ b/app/src/main/java/io/heckel/ntfy/ui/TrustedCertificateFragment.kt
@@ -62,6 +62,7 @@ class TrustedCertificateFragment : DialogFragment() {
 
     // Page 2 views
     private lateinit var page2Layout: LinearLayout
+    private lateinit var securityWarningLayout: LinearLayout
     private lateinit var descriptionText: TextView
     private lateinit var warningText: TextView
     private lateinit var baseUrlValueLabel: TextView
@@ -174,6 +175,7 @@ class TrustedCertificateFragment : DialogFragment() {
 
         // Page 2 views
         page2Layout = view.findViewById(R.id.trusted_certificate_page2)
+        securityWarningLayout = view.findViewById(R.id.trusted_certificate_security_warning)
         descriptionText = view.findViewById(R.id.trusted_certificate_description)
         warningText = view.findViewById(R.id.trusted_certificate_warning)
         baseUrlValueLabel = view.findViewById(R.id.trusted_certificate_base_url_value_label)
@@ -196,7 +198,7 @@ class TrustedCertificateFragment : DialogFragment() {
     }
 
     private fun setupUnknownMode() {
-        // Go directly to page 2 with details
+        // Go directly to page 2 with details and security warning
         toolbar.setTitle(R.string.trusted_certificate_dialog_title_unknown)
         toolbar.setNavigationIcon(R.drawable.ic_close_white_24dp)
         page1Layout.isVisible = false
@@ -205,8 +207,9 @@ class TrustedCertificateFragment : DialogFragment() {
         trustMenuItem.isVisible = true
         deleteMenuItem.isVisible = false
 
-        descriptionText.setText(R.string.trusted_certificate_dialog_description_unknown)
-        descriptionText.isVisible = true
+        // Show security warning banner instead of description
+        securityWarningLayout.isVisible = true
+        descriptionText.isVisible = false
         baseUrlValueLabel.isVisible = true
         baseUrlValueText.isVisible = true
         baseUrlValueText.text = baseUrl
diff --git a/app/src/main/res/drawable/ic_warning_amber_24dp.xml b/app/src/main/res/drawable/ic_warning_amber_24dp.xml
new file mode 100644
index 00000000..d35dd04b
--- /dev/null
+++ b/app/src/main/res/drawable/ic_warning_amber_24dp.xml
@@ -0,0 +1,10 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+    <path
+        android:fillColor="#FF8C00"
+        android:pathData="M1,21h22L12,2 1,21zM13,18h-2v-2h2v2zM13,14h-2v-4h2v4z"/>
+</vector>
+
diff --git a/app/src/main/res/layout/fragment_trusted_certificate_dialog.xml b/app/src/main/res/layout/fragment_trusted_certificate_dialog.xml
index 5dc0e3c8..f4e7088f 100644
--- a/app/src/main/res/layout/fragment_trusted_certificate_dialog.xml
+++ b/app/src/main/res/layout/fragment_trusted_certificate_dialog.xml
@@ -96,7 +96,50 @@
                 android:orientation="vertical"
                 android:visibility="gone">
 
-                <!-- Description (shown in ADD and UNKNOWN modes) -->
+                <!-- Security warning banner (UNKNOWN mode only) -->
+                <LinearLayout
+                    android:id="@+id/trusted_certificate_security_warning"
+                    android:layout_width="match_parent"
+                    android:layout_height="wrap_content"
+                    android:orientation="vertical"
+                    android:gravity="center_horizontal"
+                    android:paddingTop="24dp"
+                    android:paddingBottom="8dp"
+                    android:visibility="gone">
+
+                    <ImageView
+                        android:layout_width="48dp"
+                        android:layout_height="48dp"
+                        android:src="@drawable/ic_warning_amber_24dp"
+                        android:importantForAccessibility="no" />
+
+                    <TextView
+                        android:id="@+id/trusted_certificate_security_title"
+                        android:layout_width="match_parent"
+                        android:layout_height="wrap_content"
+                        android:text="@string/trusted_certificate_dialog_security_title"
+                        android:textSize="20sp"
+                        android:textStyle="bold"
+                        android:textColor="@android:color/holo_orange_dark"
+                        android:gravity="center"
+                        android:paddingStart="4dp"
+                        android:paddingEnd="4dp"
+                        android:layout_marginTop="12dp" />
+
+                    <TextView
+                        android:id="@+id/trusted_certificate_security_description"
+                        android:layout_width="match_parent"
+                        android:layout_height="wrap_content"
+                        android:text="@string/trusted_certificate_dialog_security_description"
+                        android:textSize="14sp"
+                        android:gravity="center"
+                        android:paddingStart="4dp"
+                        android:paddingEnd="4dp"
+                        android:layout_marginTop="8dp" />
+
+                </LinearLayout>
+
+                <!-- Description (shown in ADD mode) -->
                 <TextView
                     android:id="@+id/trusted_certificate_description"
                     android:layout_width="match_parent"
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index ab258fb7..674fc1d6 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -431,7 +431,7 @@
     <string name="settings_advanced_certificates_trusted_item_summary">%1$s, expires %2$s</string>
     <string name="settings_advanced_certificates_trusted_item_summary_expired">%1$s, expired</string>
     <string name="settings_advanced_certificates_trusted_add_title">Add a trusted certificate</string>
-    <string name="settings_advanced_certificates_trusted_add_summary">Import a certificate into the trust store (PEM). HTTPS and WebSocket connections will trust this certificate.</string>
+    <string name="settings_advanced_certificates_trusted_add_summary">Import a certificate into the trust store (PEM). When connecting to the specified ntfy server, this certificate will be trusted.</string>
     <string name="settings_advanced_certificates_client_header">Client certificates (mTLS)</string>
     <string name="settings_advanced_certificates_client_item_summary">Client certificate, issued by %1$s\nExpires %2$s, used by %3$s</string>
     <string name="settings_advanced_certificates_client_item_summary_expired">Client certificate, issued by %1$s\nExpired, used by %2$s</string>
@@ -501,11 +501,12 @@
 
     <!-- Trusted certificate dialog (TrustedCertificateFragment) -->
     <string name="trusted_certificate_dialog_title">Certificate details</string>
-    <string name="trusted_certificate_dialog_title_unknown">Unknown certificate</string>
+    <string name="trusted_certificate_dialog_title_unknown">Security warning</string>
     <string name="trusted_certificate_dialog_title_add">Add trusted certificate</string>
     <string name="trusted_certificate_dialog_description">The server\'s certificate could not be verified. Review the details below before trusting.</string>
-    <string name="trusted_certificate_dialog_description_unknown">The server\'s certificate could not be verified. Review the details below before trusting.</string>
-    <string name="trusted_certificate_dialog_description_add">You\'ve selected a certificate file. Please review the details below before adding it to your trusted certificates.</string>
+    <string name="trusted_certificate_dialog_security_title">Your connection is not private</string>
+    <string name="trusted_certificate_dialog_security_description">Attackers might be trying to steal your information. You should not proceed unless you know why this certificate is not trusted.</string>
+    <string name="trusted_certificate_dialog_description_add">You\'ve selected a certificate file. Review the details below before adding it to your trusted certificates.</string>
     <string name="trusted_certificate_dialog_description_page1">Enter the service URL that this certificate should be pinned to. The certificate will only be trusted for this URL.</string>
     <string name="trusted_certificate_dialog_base_url_hint">Service URL</string>
     <string name="trusted_certificate_dialog_base_url_placeholder">https://ntfy.example.com</string>