--- a/browser/themes/linux/browser.css
+++ b/browser/themes/linux/browser.css
@@ -1096,21 +1096,16 @@ notification[value="translation"] button
 notification[value="translation"] menulist > .menulist-dropmarker {
   display: block;
 }
 
 #treecolAutoCompleteImage {
   max-width : 36px;
 }
 
-#PopupAutoCompleteRichResult {
-  /* The awesomebar popup should open just below the navbar bottom border. */
-  margin-top: 1px;
-}
-
 .autocomplete-richlistbox {
   padding: 4px;
 }
 
 .autocomplete-richlistitem {
   height: 30px;
   min-height: 30px;
   font: message-box;

--- a/browser/themes/linux/searchbar.css
+++ b/browser/themes/linux/searchbar.css
@@ -1,15 +1,14 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #PopupSearchAutoComplete {
   margin-inline-start: -24px;
-  padding: 1px;
 }
 
 .autocomplete-textbox-container {
   -moz-box-align: stretch;
 }
 
 .textbox-input-box {
   margin: 0;
@@ -108,17 +107,17 @@ menuitem[cmd="cmd_clearhistory"][disable
   margin: 2px 0 1px !important;
 }
 
 .search-panel-input-value {
   color: Highlight;
 }
 
 .search-panel-one-offs {
-  margin: 0 -1px !important;
+  margin: 0 !important;
   border-top: 1px solid rgba(0, 0, 0, 0.2);
 }
 
 .searchbar-engine-one-off-item {
   -moz-appearance: none;
   display: inline-block;
   border: none;
   min-width: 48px;

--- a/toolkit/themes/linux/global/autocomplete.css
+++ b/toolkit/themes/linux/global/autocomplete.css
@@ -43,21 +43,17 @@ textbox:not(.padded) .textbox-input-box 
   -moz-box-align: center;
 }
 
 /* ::::: autocomplete popups ::::: */
 
 panel[type="autocomplete"],
 panel[type="autocomplete-richlistbox"],
 .autocomplete-history-popup {
-  border-width: 1px;
-  -moz-border-top-colors: ThreeDDarkShadow;
-  -moz-border-right-colors: ThreeDDarkShadow;
-  -moz-border-bottom-colors: ThreeDDarkShadow;
-  -moz-border-left-colors: ThreeDDarkShadow;
+  border: 1px solid ThreeDShadow;
   padding: 0;
   color: -moz-FieldText;
   background-color: -moz-Field;
   -moz-appearance: none;
 }
 
 .autocomplete-history-popup {
   max-height: 180px;