diff --git a/css/leptonContent.css b/css/leptonContent.css
index 2956e617..fadb650f 100644
--- a/css/leptonContent.css
+++ b/css/leptonContent.css
@@ -2822,6 +2822,14 @@
       border-radius: 0 !important;
     }
   }
+  @-moz-document regexp(".*.pdf$") {
+    .toolbarButton,
+    .dropdownToolbarButton,
+    .secondaryToolbarButton,
+    .dialogButton {
+      border-radius: 0 !important;
+    }
+  }
 }
 @supports -moz-bool-pref("userChrome.rounding.square_dialog") {
   @-moz-document url-prefix("about:") {
@@ -2834,6 +2842,11 @@
       border-radius: 0 !important;
     }
   }
+  @-moz-document regexp(".*.pdf$") {
+    dialog {
+      border-radius: 0 !important;
+    }
+  }
 }
 @supports -moz-bool-pref("userChrome.rounding.square_checklabel") {
   @-moz-document url-prefix("about:"), url-prefix("chrome://browser/content/"), url-prefix("chrome://pippki/content/")
@@ -2870,6 +2883,12 @@
       border-radius: 0 !important;
     }
   }
+  @-moz-document regexp(".*.pdf$") {
+    .toolbarField,
+    .thumbnailSelectionRing {
+      border-radius: 0 !important;
+    }
+  }
 }
 @supports -moz-bool-pref("userChrome.rounding.square_menupopup") {
   @-moz-document url-prefix("about:"), url-prefix("chrome://")
@@ -2893,6 +2912,12 @@
       border-radius: 0 !important;
     }
   }
+  @-moz-document regexp(".*.pdf$") {
+    .doorHanger,
+    .doorHangerRight {
+      border-radius: 0 !important;
+    }
+  }
 }
 @-moz-document url("chrome://browser/content/places/places.xhtml")
 {
diff --git a/src/contents/_rounding.scss b/src/contents/_rounding.scss
index b46afcf8..fb5fff73 100644
--- a/src/contents/_rounding.scss
+++ b/src/contents/_rounding.scss
@@ -37,6 +37,15 @@
       border-radius: 0 !important;
     }
   }
+
+  @include moz-document(regexp ".*\.pdf$") {
+    .toolbarButton,
+    .dropdownToolbarButton,
+    .secondaryToolbarButton,
+    .dialogButton {
+      border-radius: 0 !important;
+    }
+  }
 }
 
 @include Option("userChrome.rounding.square_dialog") {
@@ -51,6 +60,12 @@
       border-radius: 0 !important;
     }
   }
+
+  @include moz-document(regexp ".*\.pdf$") {
+    dialog {
+      border-radius: 0 !important;
+    }
+  }
 }
 
 @include Option("userChrome.rounding.square_checklabel") {
@@ -99,6 +114,13 @@
       }
     }
   }
+
+  @include moz-document(regexp ".*\.pdf$") {
+    .toolbarField,
+    .thumbnailSelectionRing {
+      border-radius: 0 !important;
+    }
+  }
 }
 
 @include Option("userChrome.rounding.square_menupopup") {
@@ -125,4 +147,11 @@
       border-radius: 0 !important;
     }
   }
+
+  @include moz-document(regexp ".*\.pdf$") {
+    .doorHanger,
+    .doorHangerRight {
+      border-radius: 0 !important;
+    }
+  }
 }