--- a/browser/extensions/shield-recipe-client/content/about-studies/about-studies.css
+++ b/browser/extensions/shield-recipe-client/content/about-studies/about-studies.css
@@ -19,17 +19,17 @@
 
 html,
 body,
 #app {
   height: 100%;
   width: 100%;
 }
 
-button > .button-box {
+button .button-box {
   padding-left: 10px;
   padding-right: 10px;
 }
 
 .about-studies-container {
   display: flex;
   flex-direction: row;
   font-size: 1.25rem;

--- a/browser/themes/linux/places/editBookmarkOverlay.css
+++ b/browser/themes/linux/places/editBookmarkOverlay.css
@@ -22,21 +22,21 @@
 
 .expander-up,
 .expander-down {
   min-width: 0;
   padding: 2px 0;
   padding-inline-start: 2px;
 }
 
-.expander-up > .button-box {
+.expander-up .button-box {
   -moz-appearance: button-arrow-up;
 }
 
-.expander-down > .button-box {
+.expander-down .button-box {
   -moz-appearance: button-arrow-down;
 }
 
 #editBookmarkPanelContent {
   min-width: 23em;
 }
 
 #editBMPanel_folderTree {

--- a/browser/themes/linux/searchbar.css
+++ b/browser/themes/linux/searchbar.css
@@ -128,25 +128,25 @@ menuitem[cmd="cmd_clearhistory"][disable
 }
 
 .searchbar-engine-one-off-item[selected] {
   background-color: Highlight;
   background-image: none;
   color: HighlightText;
 }
 
-.searchbar-engine-one-off-item > .button-box {
+.searchbar-engine-one-off-item .button-box {
   padding: 0;
 }
 
-.searchbar-engine-one-off-item .button-box .button-text {
+.searchbar-engine-one-off-item .button-text {
   display: none;
 }
 
-.searchbar-engine-one-off-item .button-box .button-icon {
+.searchbar-engine-one-off-item .button-icon {
   display: -moz-box;
   margin-inline-end: 0;
   width: 16px;
   height: 16px;
 }
 
 .search-add-engines {
   background-color: var(--arrowpanel-dimmed);
@@ -157,17 +157,17 @@ menuitem[cmd="cmd_clearhistory"][disable
   background-color: transparent;
   color: inherit;
   border: none;
   height: 32px;
   margin: 0;
   padding: 0 10px;
 }
 
-.addengine-item > .button-box {
+.addengine-item .button-box {
   -moz-box-pack: start;
 }
 
 .addengine-item:first-of-type {
   border-top: 1px solid var(--panel-separator-color);
 }
 
 .addengine-item[selected] {
@@ -186,17 +186,17 @@ menuitem[cmd="cmd_clearhistory"][disable
 
 .addengine-badge {
   width: 16px;
   height: 16px;
   margin: -7px -9px 7px 9px;
   list-style-image: url("chrome://browser/skin/badge-add-engine.png");
 }
 
-.addengine-item .button-box .button-text {
+.addengine-item .button-text {
   -moz-box-flex: 1;
   text-align: start;
   padding-inline-start: 10px;
 }
 
 .addengine-item:not([image]) {
   list-style-image: url("chrome://browser/skin/search-engine-placeholder.png");
 }

--- a/browser/themes/osx/browser.css
+++ b/browser/themes/osx/browser.css
@@ -667,37 +667,37 @@ html|span.ac-emphasize-text-url {
 #editBookmarkPanel .expander-up {
   list-style-image: url("chrome://browser/skin/panel-expander-open.png");
 }
 
 #editBookmarkPanel .expander-down {
   list-style-image: url("chrome://browser/skin/panel-expander-closed.png");
 }
 
-#editBookmarkPanel .expander-up > .button-box > .button-icon,
-#editBookmarkPanel .expander-down > .button-box > .button-icon {
+#editBookmarkPanel .expander-up .button-icon,
+#editBookmarkPanel .expander-down .button-icon {
   margin: 1px 0 0;
 }
 
-#editBookmarkPanel .expander-up > .button-box > .button-text,
-#editBookmarkPanel .expander-down > .button-box > .button-text {
+#editBookmarkPanel .expander-up .button-text,
+#editBookmarkPanel .expander-down .button-text {
   display: none;
 }
 
 @media (min-resolution: 2dppx) {
   #editBookmarkPanel .expander-up {
     list-style-image: url("chrome://browser/skin/panel-expander-open@2x.png");
   }
 
   #editBookmarkPanel .expander-down {
     list-style-image: url("chrome://browser/skin/panel-expander-closed@2x.png");
   }
 
-  #editBookmarkPanel .expander-up > .button-box > .button-icon,
-  #editBookmarkPanel .expander-down > .button-box > .button-icon {
+  #editBookmarkPanel .expander-up .button-icon,
+  #editBookmarkPanel .expander-down .button-icon {
     width: 9px;
   }
 }
 
 #editBMPanel_tagsField > .autocomplete-textbox-container > .textbox-input-box > html|*.textbox-input::placeholder {
   opacity: 1.0;
   color: #bbb;
 }
@@ -966,29 +966,29 @@ button.translate-infobar-element[anonid=
   box-shadow: 0 1px 0 hsla(0,0%,100%,.2) inset,  0 0 0 1px hsla(0,0%,100%,.1) inset,  0 1px 0 hsla(210,54%,20%,.03),  0 0 4px hsla(206,100%,20%,.2);
 }
 
 button.translate-infobar-element.options-menu-button {
   padding-inline-start: 0.5em !important;
   padding-inline-end: 0em !important;
 }
 
-button.translate-infobar-element.options-menu-button > .button-box > .button-menu-dropmarker {
+button.translate-infobar-element.options-menu-button .button-menu-dropmarker {
   display: -moz-box;
   list-style-image: url("chrome://global/skin/icons/glyph-dropdown.png");
   padding: 0 !important;
   margin: 0 !important;
 }
 
 @media (min-resolution: 2dppx) {
-  button.translate-infobar-element.options-menu-button > .button-box > .button-menu-dropmarker {
+  button.translate-infobar-element.options-menu-button .button-menu-dropmarker {
     list-style-image: url("chrome://global/skin/icons/glyph-dropdown@2x.png");
   }
 
-  button.translate-infobar-element.options-menu-button > .button-box > .button-menu-dropmarker > .dropmarker-icon {
+  button.translate-infobar-element.options-menu-button .dropmarker-icon {
     width: 8px;
   }
 }
 
 menulist.translate-infobar-element {
   text-shadow: 0 1px 1px #FEFFFE;
   border: 1px solid;
   border-color: rgba(23, 51, 78, 0.15) rgba(23, 51, 78, 0.17) rgba(23, 51, 78, 0.2);

--- a/browser/themes/osx/downloads/downloads.css
+++ b/browser/themes/osx/downloads/downloads.css
@@ -15,17 +15,17 @@
 /*** List items and similar elements in the summary ***/
 
 :root {
   --downloads-item-height: 6em;
   --downloads-item-font-size-factor: 0.95;
   --downloads-item-details-opacity: 0.7;
 }
 
-.downloadButton:focus > .button-box {
+.downloadButton:focus .button-box {
   outline: 2px -moz-mac-focusring solid;
   outline-offset: -2px;
 }
 
 @item@[verdict="Malware"] {
   color: #aa1b08;
 }
 

--- a/browser/themes/osx/places/places.css
+++ b/browser/themes/osx/places/places.css
@@ -144,17 +144,17 @@
 #viewButton:hover {
   background: hsla(240, 5%, 5%, 0.1);
 }
 
 #viewButton[open] {
   background: hsla(240, 5%, 5%, 0.15);
 }
 
-#viewButton > .button-box > .button-menu-dropmarker {
+#viewButton .button-menu-dropmarker {
   display: -moz-box;
   list-style-image: url("chrome://global/skin/icons/arrow-dropdown-12.svg");
   width: 12px;
   height: 12px;
 }
 
 /* Trees */
 

--- a/browser/themes/osx/searchbar.css
+++ b/browser/themes/osx/searchbar.css
@@ -146,17 +146,17 @@
 .addengine-item {
   -moz-appearance: none;
   font-size: 10px;
   height: 32px;
   margin: 0;
   padding: 0 10px;
 }
 
-.addengine-item > .button-box {
+.addengine-item .button-box {
   -moz-box-pack: start;
 }
 
 .addengine-item:first-of-type {
   border-top: 1px solid var(--panel-separator-color);
 }
 
 .addengine-item[selected] {
@@ -195,17 +195,17 @@
     list-style-image: url("chrome://browser/skin/badge-add-engine@2x.png");
   }
 
   .addengine-item:not([image]) {
     list-style-image: url("chrome://browser/skin/search-engine-placeholder@2x.png");
   }
 }
 
-.addengine-item[type=menu] > .button-box > .button-menu-dropmarker {
+.addengine-item[type=menu] .button-menu-dropmarker {
   display: -moz-box;
   -moz-appearance: menuarrow !important;
   list-style-image: none;
 }
 
 .search-panel-tree > .autocomplete-treebody::-moz-tree-cell {
   border-top: none !important;
 }
@@ -237,13 +237,13 @@
   min-height: 32px;
 }
 
 .search-setting-button:hover,
 .search-setting-button[selected] {
   background-color: var(--arrowpanel-dimmed-further);
 }
 
-.search-setting-button-compact > .button-box > .button-icon {
+.search-setting-button-compact .button-icon {
   list-style-image: url("chrome://browser/skin/settings.svg");
   -moz-context-properties: fill;
   fill: currentColor;
 }

--- a/browser/themes/shared/controlcenter/panel.inc.css
+++ b/browser/themes/shared/controlcenter/panel.inc.css
@@ -145,21 +145,21 @@
   color: HighlightText;
 }
 
 .identity-popup-expander[panel-multiview-anchor]:-moz-locale-dir(rtl),
 .identity-popup-expander:not([panel-multiview-anchor]):-moz-locale-dir(ltr) {
   transform: scaleX(-1);
 }
 
-.identity-popup-expander > .button-box {
+.identity-popup-expander .button-box {
   padding: 0;
 }
 
-.identity-popup-expander:not([panel-multiview-anchor]) > .button-box {
+.identity-popup-expander:not([panel-multiview-anchor]) .button-box {
   border-right: 1px solid var(--panel-separator-color);
 }
 
 .identity-popup-expander:hover {
   background-color: var(--arrowpanel-dimmed);
   background-image: url("chrome://browser/skin/arrow-left.svg");
 }
 

--- a/browser/themes/shared/customizableui/customizeMode.inc.css
+++ b/browser/themes/shared/customizableui/customizeMode.inc.css
@@ -81,17 +81,17 @@
 
 #customization-done-button {
   color: #fff;
   font-weight: 700;
   border-color: #0060df;
   background-color: #0a84ff;
 }
 
-.customizationmode-button > .box-inherit {
+.customizationmode-button .box-inherit {
   border-width: 0;
   padding: 3px 0;
   padding-inline-start: 0;
   padding-inline-end: 0;
 }
 
 /* We use a smaller padding to ensure images don't have padding.
  * We can't detect whether a button has an image. This button doesn't
@@ -558,17 +558,17 @@ toolbarpaletteitem[place=toolbar] > tool
   padding: 0;
 }
 
 #ready-player-one {
   /* Don't need HiDPI versions since the size used will be scaled down to 20x20. */
   list-style-image: url("chrome://browser/skin/customizableui/whimsy.png");
 }
 
-#ready-player-one > .button-box > .button-icon {
+#ready-player-one .button-icon {
   width: 16px;
   height: 16px;
 }
 
 #customization-palette[whimsypong] {
   /* Keep the palette in the render tree but invisible
      so -moz-element() will work. */
   padding: 0;

--- a/browser/themes/shared/downloads/contentAreaDownloadsView.css
+++ b/browser/themes/shared/downloads/contentAreaDownloadsView.css
@@ -15,17 +15,17 @@
 
 .downloadButton:not([disabled="true"]):hover,
 .downloadButton:not([disabled="true"]):hover:active,
 .downloadButton:not([disabled]):hover:active {
   background: transparent;
   border: none;
 }
 
-.downloadButton > .button-box {
+.downloadButton .button-box {
   padding-bottom: 0;
 }
 
 #downloadsListEmptyDescription {
   margin: 1em;
   text-align: center;
   color: GrayText;
 }

--- a/browser/themes/shared/downloads/downloads.inc.css
+++ b/browser/themes/shared/downloads/downloads.inc.css
@@ -82,17 +82,17 @@
 .downloadsPanelFooterButton[default]:hover {
   background-color: #0675d3;
 }
 
 .downloadsPanelFooterButton[default]:hover:active {
   background-color: #0568ba;
 }
 
-.downloadsPanelFooterButton > .button-box {
+.downloadsPanelFooterButton .button-box {
   padding: 0;
 }
 
 #downloadsHistory {
   padding-inline-start: 14px;
   padding-inline-end: 14px;
 }
 
@@ -240,25 +240,25 @@ richlistitem[type="download"]:last-child
   min-width: 58px;
   margin: 0;
   border: none;
   background: transparent;
   padding: 0;
   color: inherit;
 }
 
-.downloadButton > .button-box > .button-icon {
+.downloadButton .button-icon {
   width: 16px;
   height: 16px;
   margin: 1px;
   -moz-context-properties: fill;
   fill: currentColor;
 }
 
-.downloadButton > .button-box > .button-text {
+.downloadButton .button-text {
   margin: 0 !important;
   padding: 0;
 }
 
 @itemFinished@[exists] .downloadMainArea:hover,
 @item@:not([verdict]) > .downloadButtonArea:hover,
 @item@[verdict]:hover {
   background-color: var(--arrowpanel-dimmed);
@@ -273,37 +273,37 @@ richlistitem[type="download"]:last-child
 @item@[verdict="Malware"]:hover,
 @item@[verdict="Malware"]:hover:active {
   background-color: #aa1b08;
   color: white;
 }
 
 /*** Button icons ***/
 
-.downloadIconCancel > .button-box > .button-icon {
+.downloadIconCancel .button-icon {
   list-style-image: url("chrome://browser/skin/panel-icon-cancel.svg");
 }
 
-.downloadIconShow > .button-box > .button-icon {
+.downloadIconShow .button-icon {
 %ifdef XP_MACOSX
   list-style-image: url("chrome://browser/skin/panel-icon-magnifier.svg");
 %else
   list-style-image: url("chrome://browser/skin/panel-icon-folder.svg");
 %endif
 }
 
-.downloadIconRetry > .button-box > .button-icon {
+.downloadIconRetry .button-icon {
   list-style-image: url("chrome://browser/skin/panel-icon-retry.svg");
 }
 
-.downloadShowBlockedInfo > .button-box > .button-icon {
+.downloadShowBlockedInfo .button-icon {
   list-style-image: url("chrome://browser/skin/panel-icon-arrow-right.svg");
 }
 
-.downloadShowBlockedInfo > .button-box > .button-icon:-moz-locale-dir(rtl) {
+.downloadShowBlockedInfo .button-icon:-moz-locale-dir(rtl) {
   list-style-image: url("chrome://browser/skin/panel-icon-arrow-left.svg");
 }
 
 /*** Blocked subview ***/
 
 #downloadsPanel-blockedSubview > .panel-view-body-unscrollable {
   background-image: url("chrome://browser/skin/warning.svg");
   background-size: 32px 32px;

--- a/browser/themes/windows/browser.css
+++ b/browser/themes/windows/browser.css
@@ -959,28 +959,28 @@ notification[value="translation"] {
     border: 1px solid #006B9D;
   }
 
   notification[value="translation"] button[anonid="translate"]:hover,
   notification[value="translation"] button[anonid="translate"]:active {
     background-color: #008ACB;
   }
 
-  notification[value="translation"] button[type="menu"] > .button-box > .button-menu-dropmarker,
+  notification[value="translation"] button[type="menu"] .button-menu-dropmarker,
   notification[value="translation"] menulist > .menulist-dropmarker {
     list-style-image: url("chrome://browser/skin/toolbarbutton-dropdown-arrow.png");
   }
 
-  notification[value="translation"] button > .button-box,
-  notification[value="translation"] button[type="menu"] > .button-box > .button-menu-dropmarker {
+  notification[value="translation"] button .button-box,
+  notification[value="translation"] button[type="menu"] .button-menu-dropmarker {
     padding: 0;
     margin-inline-start: 3ch;
   }
 
-  notification[value="translation"] button:not([type="menu"]) > .button-box {
+  notification[value="translation"] button:not([type="menu"]) .button-box {
     margin-inline-end: 3ch;
   }
 }
 
 .translation-menupopup {
   -moz-appearance: none;
 }
 

--- a/browser/themes/windows/newtab/newTab.css
+++ b/browser/themes/windows/newtab/newTab.css
@@ -4,11 +4,11 @@
 
 %include ../../shared/newtab/newTab.inc.css
 
 
 .newtab-undo-button {
   color: rgb(0,102,204);
 }
 
-.newtab-undo-button > .button-box {
+.newtab-undo-button .button-box {
   padding: 0;
 }

--- a/browser/themes/windows/places/editBookmarkOverlay.css
+++ b/browser/themes/windows/places/editBookmarkOverlay.css
@@ -22,18 +22,18 @@
 
 .expander-up,
 .expander-down {
   min-width: 0;
   margin: 0;
   margin-inline-end: 4px;
 }
 
-.expander-up > .button-box,
-.expander-down > .button-box {
+.expander-up .button-box,
+.expander-down .button-box {
   padding: 0;
 }
 
 .expander-up {
   list-style-image: url("chrome://global/skin/icons/collapse.png");
 }
 
 .expander-down {

--- a/browser/themes/windows/places/places.css
+++ b/browser/themes/windows/places/places.css
@@ -64,17 +64,17 @@
 #viewButton:hover {
   background-color: hsla(240, 5%, 5%, .1);
 }
 
 #viewButton[open] {
   background-color: hsla(240, 5%, 5%, .15);
 }
 
-#viewButton > .button-box > .button-menu-dropmarker {
+#viewButton .button-menu-dropmarker {
   height: auto;
   width: auto;
   margin-inline-end: -3px;
 }
 
 #sidebar-search-container {
   padding: 8px;
 }

--- a/browser/themes/windows/sanitizeDialog.css
+++ b/browser/themes/windows/sanitizeDialog.css
@@ -58,18 +58,18 @@
 }
 
 .expander-up,
 .expander-down {
   min-width: 0;
   margin: 0;
 }
 
-.expander-up > .button-box,
-.expander-down > .button-box {
+.expander-up .button-box,
+.expander-down .button-box {
   padding: 0;
 }
 
 .expander-up {
   list-style-image: url("chrome://global/skin/icons/collapse.png");
 }
 
 .expander-down {

--- a/browser/themes/windows/searchbar.css
+++ b/browser/themes/windows/searchbar.css
@@ -126,17 +126,17 @@
 }
 
 .searchbar-engine-one-off-item[selected] {
   background-color: Highlight;
   background-image: none;
   color: HighlightText;
 }
 
-.searchbar-engine-one-off-item > .button-box {
+.searchbar-engine-one-off-item .button-box {
   padding: 0;
 }
 
 .searchbar-engine-one-off-item .button-text {
   display: none;
 }
 
 .searchbar-engine-one-off-item .button-icon {
@@ -151,17 +151,17 @@
 .addengine-item {
   -moz-appearance: none;
   border: none;
   height: 32px;
   margin: 0;
   padding: 0 10px;
 }
 
-.addengine-item > .button-box {
+.addengine-item .button-box {
   -moz-box-pack: start;
 }
 
 .addengine-item:first-of-type {
   border-top: 1px solid var(--panel-separator-color);
 }
 
 .addengine-item[selected] {

--- a/devtools/client/themes/breadcrumbs.css
+++ b/devtools/client/themes/breadcrumbs.css
@@ -88,23 +88,23 @@
 .breadcrumbs-widget-item {
   background-color: transparent;
   border: none;
   margin-inline-start: 10px;
   margin-inline-end: 1px;
   padding: 0 0 2px 0;
 }
 
-.breadcrumbs-widget-item > .button-box {
+.breadcrumbs-widget-item .button-box {
   border: none;
   padding-top: 0;
   padding-bottom: 0;
 }
 
-:root[platform="win"] .breadcrumbs-widget-item:-moz-focusring > .button-box {
+:root[platform="win"] .breadcrumbs-widget-item:-moz-focusring .button-box {
   border-width: 0;
 }
 
 #debugger-toolbar .breadcrumbs-widget-item::before {
   --background-color: var(--theme-toolbar-background);
 }
 
 .breadcrumbs-widget-item:first-child::before {
@@ -177,17 +177,17 @@
 
 .theme-firebug .breadcrumbs-widget-item:hover {
   border-color: rgba(0, 0, 0, 0.2);
   box-shadow: 1px 1px 1px rgba(255, 255, 255, 0.6) inset,
               0 0 1px rgba(255, 255, 255, 0.6) inset,
               0 0 2px rgba(0, 0, 0, 0.05);
 }
 
-.theme-firebug .breadcrumbs-widget-item > .button-box {
+.theme-firebug .breadcrumbs-widget-item .button-box {
   padding-left: 0;
   padding-right: 0;
 }
 
 .theme-firebug .breadcrumbs-widget-item:first-child {
   margin: 0;
 }
 

--- a/toolkit/themes/linux/mozapps/extensions/extensions.css
+++ b/toolkit/themes/linux/mozapps/extensions/extensions.css
@@ -19,17 +19,17 @@
   display: -moz-box;
   list-style-image: url("moz-icon://stock/gtk-sort-ascending?size=16");
 }
 
 .addon .relnotes-toggle {
   list-style-image: url("moz-icon://stock/gtk-go-down?size=16");
 }
 
-.addon .relnotes-toggle > .button-box > .button-icon {
+.addon .relnotes-toggle .button-icon {
   display: -moz-box;
 }
 
 .addon[show-relnotes] .relnotes-toggle {
   list-style-image: url("moz-icon://stock/gtk-go-up?size=16");
 }
 
 .meta-rating[showrating="average"] > .star {

--- a/toolkit/themes/linux/mozapps/update/updates.css
+++ b/toolkit/themes/linux/mozapps/update/updates.css
@@ -66,17 +66,17 @@ wizardpage {
   border: none;
   min-width: 0;
   min-height: 0;
   margin: 0;
   padding: 0;
 }
 
 /* !Important must be used otherwise this won't immediately take affect */
-#pauseButton > .button-box {
+#pauseButton .button-box {
   padding: 0 !important;
 }
 
 #pauseButton[disabled="true"] {
   list-style-image: url("moz-icon://stock/gtk-media-pause?size=menu&state=disabled");
 }
 
 #pauseButton[paused="true"] {

--- a/toolkit/themes/osx/global/global.css
+++ b/toolkit/themes/osx/global/global.css
@@ -273,17 +273,17 @@ notification > button:active:hover {
 notification > button:-moz-focusring {
   box-shadow: var(--focus-ring-box-shadow), @roundButtonShadow@;
 }
 
 notification > button:active:hover:-moz-focusring {
   box-shadow: var(--focus-ring-box-shadow), @roundButtonPressedShadow@;
 }
 
-notification > button > .button-box > .button-text {
+notification > button .button-text {
   margin: 0 !important;
 }
 
 popupnotificationcontent {
   margin-top: .5em;
 }
 
 %include ../../shared/notification-popup.inc.css

--- a/toolkit/themes/osx/global/in-content/common.css
+++ b/toolkit/themes/osx/global/in-content/common.css
@@ -40,17 +40,17 @@ xul|menulist:not([editable="true"]) > xu
 
 xul|menulist > xul|menupopup xul|menu,
 xul|menulist > xul|menupopup xul|menuitem,
 xul|button[type="menu"] > xul|menupopup xul|menu,
 xul|button[type="menu"] > xul|menupopup xul|menuitem {
   padding-inline-end: 34px;
 }
 
-xul|*.help-button > xul|*.button-box > xul|*.button-icon {
+xul|*.help-button xul|*.button-icon {
   margin-inline-start: 0;
 }
 
 xul|*.checkbox-icon {
   margin-right: 0;
 }
 
 xul|*.radio-icon {
@@ -97,22 +97,22 @@ xul|*.spinbuttons-up {
   border-radius: 4px 4px 0 0;
 }
 
 xul|*.spinbuttons-down  {
   margin-bottom: 0 !important;
   border-radius: 0 0 4px 4px;
 }
 
-xul|*.spinbuttons-button > xul|*.button-box {
+xul|*.spinbuttons-button xul|*.button-box {
   padding-inline-start: 2px !important;
   padding-inline-end: 3px !important;
 }
 
-xul|*.spinbuttons-button > xul|*.button-box > xul|*.button-text {
+xul|*.spinbuttons-button xul|*.button-text {
   display: none;
 }
 
 xul|textbox[type="search"]:not([searchbutton]) > .textbox-input-box > .textbox-search-sign {
   list-style-image: url(chrome://global/skin/icons/search-textbox.svg);
   margin-inline-end: 5px;
 }
 

--- a/toolkit/themes/osx/mozapps/update/updates.css
+++ b/toolkit/themes/osx/mozapps/update/updates.css
@@ -95,17 +95,17 @@ wizardpage {
   min-width: 16px;
   max-height: 16px;
   max-width: 16px;
   margin: 0 1px 0 1px;
   padding: 0;
 }
 
 /* !Important must be used otherwise this won't immediately take affect */
-#pauseButton > .button-box {
+#pauseButton .button-box {
   padding: 0 !important;
 }
 
 #pauseButton:hover {
   -moz-image-region: rect(48px, 32px, 64px, 16px);
 }
 
 #pauseButton:not([disabled="true"]):hover:active {

--- a/toolkit/themes/shared/extensions/extensions.inc.css
+++ b/toolkit/themes/shared/extensions/extensions.inc.css
@@ -574,17 +574,17 @@ button.warning {
 .addon .relnotes-toggle {
   -moz-appearance: none;
   border: none;
   background: transparent;
   font-weight: bold;
   cursor: pointer;
 }
 
-.addon .relnotes-toggle > .button-box > .button-icon {
+.addon .relnotes-toggle .button-icon {
   padding-inline-start: 4px;
 }
 
 .addon-view[notification],
 .addon-view[pending] {
   --view-highlight-color: transparent;
   background-image: radial-gradient(at 50% 0%,
                                     var(--view-highlight-color) 0%,

--- a/toolkit/themes/shared/popupnotification.inc.css
+++ b/toolkit/themes/shared/popupnotification.inc.css
@@ -94,17 +94,17 @@
 .popup-notification-button[default][highlight="true"]:hover:active:not([disabled]) {
   background-color: #0568ba;
 }
 
 .popup-notification-button[anonid="secondarybutton"][hidden="true"] ~ .popup-notification-button[default] {
   flex: 1;
 }
 
-.popup-notification-button > .button-box {
+.popup-notification-button .button-box {
   padding: 0;
 }
 
 .popup-notification-dropmarker {
   flex: none;
   padding: 0 15px;
 }
 

--- a/toolkit/themes/windows/global/button.css
+++ b/toolkit/themes/windows/global/button.css
@@ -51,17 +51,17 @@ button:-moz-focusring {
       color: HighlightText;
     }
   }
 }
 
 /* .......... active/open/checked state .......... */
 
 @media (-moz-windows-classic) {
-  button:-moz-any(:hover:active,[open="true"],[checked="true"]):not([disabled="true"]) > .button-box {
+  button:-moz-any(:hover:active,[open="true"],[checked="true"]):not([disabled="true"]) .button-box {
     padding-top: 3px;
     padding-bottom: 2px;
     padding-inline-start: 5px;
     padding-inline-end: 4px;
   }
 }
 
 /* .......... disabled state .......... */

--- a/toolkit/themes/windows/global/notification.css
+++ b/toolkit/themes/windows/global/notification.css
@@ -3,17 +3,17 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 @namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
 
 %include ../../shared/notification.inc.css
 %include ../../shared/popupnotification.inc.css
 
 /* Override default icon size which is too small for this dropdown */
-.popup-notification-dropmarker > .button-box > .button-menu-dropmarker {
+.popup-notification-dropmarker .button-menu-dropmarker {
   width: 16px;
   height: 16px;
 }
 
 @media (-moz-windows-default-theme) {
   .popup-notification-warning {
     color: #aa1b08;
   }

--- a/toolkit/themes/windows/mozapps/update/updates.css
+++ b/toolkit/themes/windows/mozapps/update/updates.css
@@ -67,17 +67,17 @@ wizardpage {
   border: none;
   min-width: 0;
   min-height: 0;
   margin: 0;
   padding: 0;
 }
 
 /* !Important must be used otherwise this won't immediately take affect */
-#pauseButton > .button-box {
+#pauseButton .button-box {
   padding: 0 !important;
 }
 
 #pauseButton:hover {
   -moz-image-region: rect(16px, 48px, 32px, 32px);
 }
 
 #pauseButton:active {