--- a/mail/components/im/modules/chatNotifications.jsm
+++ b/mail/components/im/modules/chatNotifications.jsm
@@ -93,17 +93,17 @@ var Notifications = {
         }
 
         // Handle third person messages
         name = aMessage.alias || aMessage.who;
         if (messageText && messageText.startsWith("/me "))
           messageText = messageText.replace(/^\/me/, name);
       case 2:
         if (!icon)
-          icon = "chrome://messenger/skin/userIcon.png";
+          icon = "chrome://messenger/skin/icons/userIcon.svg";
 
         if (!messageText) {
           let bundle = new StringBundle("chrome://messenger/locale/chat.properties");
           messageText = bundle.get("messagePreview");
         }
     }
 
     // Show the notification!

--- a/mail/components/im/themes/chat.css
+++ b/mail/components/im/themes/chat.css
@@ -281,66 +281,60 @@ imcontact[aliasing] .contactDisplayName 
   min-height: 135px;
 }
 
 .conv-top {
   min-height: 60px;
 }
 
 .conv-top-info {
-  margin: 0 0;
-  padding: 0 0;
+  margin: 0;
+  padding: 0.6ex;
   border-style: none;
   -moz-appearance: none;
   -moz-window-dragging: no-drag;
-%ifdef XP_MACOSX
-  /* Copy of .main-header-area from osx/mail/messageHeader.css */
-  color: #2E3436; /* Aluminium 6 */
-  border-bottom:1px solid #BFBFBF !important;
-  padding: 0.6ex;
-%else
-  background-color: -moz-Dialog;
-%ifdef XP_WIN
-  background-image: linear-gradient(rgba(255,255,255,.5), rgba(255,255,255,0));
-%else
-  background-image: linear-gradient(rgba(255,255,255,.3), rgba(255,255,255,0));
-%endif
-%ifndef XP_WIN
-  border-bottom: 1px solid ThreeDShadow;
-%else
-  border-bottom: none;
-%endif
-%endif
+  border-bottom: 1px solid var(--splitter-color);
 }
 
 .userIconHolder {
   border: 2px solid rgba(0,0,0,0.15);
   border-radius: 5px;
   overflow: hidden;
 }
 
+:root[lwt-tree-brighttext] .userIconHolder {
+  border-color: rgba(255,255,255,0.15);
+}
+
 .userIcon,
 .userIconHolder {
   max-width: 48px;
   max-height: 48px;
   min-width: 48px;
   min-height: 48px;
   width: 48px;
   height: 48px;
 }
 
 .userIcon:not([src]),
 .userIconHolder:not([userIcon]) {
   display: none;
 }
 
 .userIcon[src=""] {
-  background-image: url("chrome://messenger/skin/userIcon.png");
+  background-image: url("chrome://messenger/skin/icons/userIcon.svg");
   background-size: contain;
   background-repeat: no-repeat;
+  -moz-context-properties: fill, fill-opacity;
+  fill: #000;
+  fill-opacity: 0.25;
+}
+
+:root[lwt-tree-brighttext] .userIcon[src=""] {
+  fill: #fff;
 }
 
 .statusTypeIcon {
   margin: 32px 0 0;
   width: 16px;
   height: 16px;
   max-width: 16px;
   max-height: 16px;
@@ -445,20 +439,18 @@ richlistitem[state="disconnected"] .acco
   .prplIcon,
   #statusTypeIcon .button-icon {
     width: 16px;
     height: 16px;
   }
 }
 
 .statusMessage {
-  margin: 0 0 !important;
-%ifdef XP_MACOSX
+  margin: 32px 0 0;
   min-height: 16px;
-%endif
 }
 
 .statusMessage[noTopic]:not([editing]),
 .statusMessageWithDash[noTopic] {
   font-style: italic;
 }
 
 .status-overlay-icon[status="away"],
@@ -483,65 +475,34 @@ richlistitem[state="disconnected"] .acco
 }
 
 /* corresponds to im/themes/conversation.css @media all and (min-height: 251px) */
 .statusImageStack,
 .displayNameAndstatusMessageStack {
   margin: 2px 2px;
 }
 
-.statusMessage {
-  margin-top: 32px !important;
-}
-
-.statusMessage[editing] {
-%ifdef XP_MACOSX
-  margin: 29px 0 -1px -4px !important;
-%else
-%ifdef XP_WIN
-  margin: 28px 0 -1px -2px !important;
-%else
-  margin: 29px 0 -3px -4px !important;
-%endif
-%endif
-}
-
 .displayName {
   font-size: 16px;
-  border-bottom: 1px solid rgba(0,0,0,0.25);
-  margin: 0 0 16px !important;
+  border-bottom: 1px solid var(--splitter-color);
+  margin: 0 0 16px;
   padding-right: 20px;
 }
 
 .prplIcon {
-  margin-top: 0 !important;
-  margin-inline-end: 1px !important;
-  margin-bottom: 16px !important;
-  margin-inline-start: -16px !important;
+  margin-top: 0;
+  margin-inline-end: 1px;
+  margin-bottom: 16px ;
+  margin-inline-start: -16px;
 }
 
 .conv-messages {
   min-width: 150px;
-%ifndef XP_MACOSX
-%ifndef XP_WIN
-  border-bottom: solid 1px GrayText;
-%else
-  border: 1px solid rgba(0, 0, 0, 0.25);
-  border-left: none;
-  border-right: none !important;
-%endif
-%endif
 }
 
-%ifndef XP_MACOSX
-.conv-messages[chat] {
-  border-right: solid 1px GrayText;
-}
-%endif
-
 /* Animation copied from the find bar in Firefox - http://dxr.mozilla.org/mozilla-central/source/toolkit/themes/linux/global/findBar.css#7 */
 .conv-status-container {
   display: block;
   height: 20px;
   padding: 3px;
   border-bottom: 1px solid ThreeDShadow;
   transition-property: margin-top, opacity, visibility;
   transition-duration: 150ms, 150ms, 0s;
@@ -651,21 +612,17 @@ richlistitem[state="disconnected"] .acco
   height: 5px;
   background-color: transparent;
   /* make only the splitter border visible */
   margin-top: -5px;
   margin-inline-start: 0;
   /* because of the negative margin needed to make the splitter visible */
   position: relative;
   z-index: 10;
-%ifdef XP_MACOSX
-  border-bottom: 1px solid #bdbdbd;
-%else
-  border-bottom: 1px solid ThreeDShadow;
-%endif
+  border-bottom: 1px solid var(--splitter-color);
 }
 
 /* Adaptation of #folderpane_splitter */
 #listSplitter,
 #contextSplitter {
   margin-top: 0;
   /* splitter grip area */
   width: 5px;
@@ -681,21 +638,17 @@ richlistitem[state="disconnected"] .acco
   margin-inline-end: -5px;
 }
 
 #listSplitter[state="collapsed"]:hover {
   border-inline-start: 4px solid highlight;
 }
 
 #contextSplitter {
-%ifdef XP_MACOSX
-  border-inline-end: 1px solid #bdbdbd;
-%else
-  border-inline-end: 1px solid ThreeDShadow;
-%endif
+  border-inline-end: 1px solid var(--splitter-color);
   /* make only the splitter border visible */
   margin-inline-start: -5px;
 }
 
 #contextSplitter[state="collapsed"]:hover {
   border-inline-end: 4px solid highlight;
 }
 

--- a/mail/components/im/themes/imAccounts.css
+++ b/mail/components/im/themes/imAccounts.css
@@ -150,17 +150,16 @@ richlistitem[dragover="up"] {
 
 richlistitem[state="connecting"] .accountStateIcon {
   list-style-image: url("chrome://global/skin/icons/loading.png");
 }
 richlistitem[error="true"] .accountStateIcon {
   list-style-image: url("chrome://global/skin/icons/warning.svg");
 }
 
-
 #statusArea {
   margin: 0 0;
   padding: 0 0;
 }
 
 #displayName {
   font-size: 16px;
   border-bottom: 1px solid rgba(0,0,0,0.25);
@@ -176,19 +175,22 @@ richlistitem[error="true"] .accountState
   border-radius: 5px;
   max-width: 48px;
   max-height: 48px;
   width: 48px;
   height: 48px;
 }
 
 #userIcon[src=""] {
-  background-image: url("chrome://messenger/skin/userIcon.png");
+  background-image: url("chrome://messenger/skin/icons/userIcon.svg");
   background-size: contain;
   background-repeat: no-repeat;
+  -moz-context-properties: fill, fill-opacity;
+  fill: #000;
+  fill-opacity: 0.25;
 }
 
 #userIcon:hover {
   border-color: rgba(0,0,0,0.35);
   background-color: rgba(0,0,0,0.35);
   opacity: .4;
 }
 

--- a/mail/components/mailGlue.js
+++ b/mail/components/mailGlue.js
@@ -200,17 +200,17 @@ MailGlue.prototype = {
       toolbarColor: "hsl(240, 1%, 20%)",
       toolbar_bottom_separator: "hsla(240, 5%, 5%, 0.2",
       toolbar_field: "rgb(71, 71, 73)",
       toolbar_field_border: "rgba(249, 249, 250, 0.2)",
       toolbar_field_separator: "#5F6670",
       toolbar_field_text: "rgb(249, 249, 250)",
       sidebar: "#38383D",
       sidebar_text: "rgb(249, 249, 250)",
-      sidebar_border: "rgba(255, 255, 255, 0.2)",
+      sidebar_border: "#606064",
       author: vendorShortName,
     }, {
       useInDarkMode: true,
     });
   },
 
   _onMailStartupDone() {
     // On Windows 7 and above, initialize the jump list module.

--- a/mail/themes/linux/jar.mn
+++ b/mail/themes/linux/jar.mn
@@ -6,17 +6,16 @@ classic.jar:
 % skin messenger classic/1.0 %skin/classic/messenger/
 #include ../shared/jar.inc.mn
   skin/classic/messenger/primaryToolbar.css                   (mail/primaryToolbar.css)
   skin/classic/messenger/accountCentral.css                   (mail/accountCentral.css)
   skin/classic/messenger/accountCreation.css                  (mail/accountCreation.css)
   skin/classic/messenger/accountManage.css                    (mail/accountManage.css)
   skin/classic/messenger/accountWizard.css                    (mail/accountWizard.css)
 * skin/classic/messenger/chat.css                             (mail/chat.css)
-  skin/classic/messenger/userIcon.png                         (mail/userIcon.png)
 * skin/classic/messenger/imAccounts.css                       (../../components/im/themes/imAccounts.css)
 * skin/classic/messenger/imAccountWizard.css                  (../../components/im/themes/imAccountWizard.css)
   skin/classic/messenger/imMenulist.css                       (../../components/im/themes/imMenulist.css)
 * skin/classic/messenger/imRichlistbox.css                    (../../components/im/themes/imRichlistbox.css)
   skin/classic/messenger/founder.png                          (../../components/im/themes/founder.png)
   skin/classic/messenger/operator.png                         (../../components/im/themes/operator.png)
   skin/classic/messenger/half-operator.png                    (../../components/im/themes/half-operator.png)
   skin/classic/messenger/voice.png                            (../../components/im/themes/voice.png)

--- a/mail/themes/linux/mail/addrbook/addressbook.css
+++ b/mail/themes/linux/mail/addrbook/addressbook.css
@@ -33,29 +33,29 @@
 #dirTree:not(:-moz-lwtheme) {
   border-bottom: 1px solid ThreeDShadow;
 }
 
 /* ::::: splitters ::::: */
 
 #dirTree-splitter {
   -moz-appearance: none;
-  border-inline-end: 1px solid ThreeDShadow;
+  border-inline-end: 1px solid var(--splitter-color);
   /* splitter grip area */
   width: 4px;
   /* make only the splitter border visible */
   margin-inline-start: -4px;
   /* because of the negative margin needed to make the splitter visible */
   position: relative;
   z-index: 10;
 }
 
 #results-splitter {
   -moz-appearance: none;
-  border-top: 1px solid ThreeDShadow;
+  border-top: 1px solid var(--splitter-color);
   /* splitter grip area */
   height: 4px;
   /* make only the splitter border visible */
   margin-bottom: -4px;
   /* because of the negative margin needed to make the splitter visible */
   position: relative;
   z-index: 10;
 }

--- a/mail/themes/linux/mail/attachmentList.css
+++ b/mail/themes/linux/mail/attachmentList.css
@@ -16,43 +16,15 @@
 .attachmentcell-size {
   padding-top: 1px;
 }
 
 .attachmentcell-size {
   color: GrayText;
 }
 
-.attachmentList[orient="horizontal"] > .attachmentItem {
-  pointer-events: none;
-}
-
-.attachmentList[orient="horizontal"] .attachmentcell-icon,
-.attachmentList[orient="horizontal"] .attachmentcell-nameselection {
-  pointer-events: auto;
-}
-
-.attachmentList:focus > .attachmentItem[selected="true"][current="true"] .attachmentcell-nameselection {
-  outline: 1px dotted #F3D982;
-}
-
-.attachmentList:focus > .attachmentItem[current="true"] .attachmentcell-nameselection {
-  outline: 1px dotted;
-  outline-offset: -1px;
-}
-
-.attachmentItem[selected="true"] .attachmentcell-nameselection {
-  background-color: -moz-CellHighlight;
-  color: -moz-CellHighlightText;
-}
-
-.attachmentList:focus > .attachmentItem[selected="true"] .attachmentcell-nameselection {
-  background-color: Highlight;
-  color: HighlightText;
-}
-
 .attachmentItem[selected="true"] .attachmentcell-icon {
   filter: url("chrome://messenger/skin/imageFilters.svg#selected");
 }
 
 .attachmentList:focus > .attachmentItem[selected="true"] .attachmentcell-icon {
   filter: url("chrome://messenger/skin/imageFilters.svg#selected-focus");
 }

--- a/mail/themes/linux/mail/chat.css
+++ b/mail/themes/linux/mail/chat.css
@@ -4,17 +4,17 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 %endif
 
 %include ../../../components/im/themes/chat.css
 
 #chatTabPanel {
   --imbox-selected-text-color: -moz-FieldText;
   --imbox-selected-background-color: -moz-Field;
-  --imbox-selected-border-color: ThreeDShadow;
+  --imbox-selected-border-color: var(--splitter-color);
   --imgroup-selected-background-color: ThreeDLightShadow;
 }
 
 .convUnreadCount,
 .contactDisplayName,
 .convDisplayName,
 .contactStatusText,
 .convStatusText {
@@ -39,18 +39,18 @@
   border: none;
 }
 
 .conv-textbox {
   margin: 0;
   -moz-appearance: none;
 }
 
-#conv-top-info {
-  -moz-appearance: none;
+:root:not([lwt-tree]) #conv-top-info {
+  background-color: -moz-Dialog;
   color: -moz-DialogText;
 }
 
 .conv-nicklist-header,
 .conv-logs-header-label {
   color: -moz-DialogText;
   background-color: -moz-Dialog;
   padding-inline-start: 3px;
@@ -60,16 +60,21 @@
 .closeConversationButton > .button-box > .button-icon {
   margin-inline-end: 0;
 }
 
 .conv-hbox {
   -moz-box-align: center;
 }
 
+.statusMessage[editing] {
+  color: -moz-dialogtext;
+  margin: 29px 0 -3px -4px;
+}
+
 #displayNameAndstatusMessageStack #statusMessage {
   margin: 32px 0 0;
 }
 
 #displayNameAndstatusMessageStack #statusMessage[editing] {
   margin: 30px -2px -2px -4px;
 }
 

--- a/mail/themes/linux/mail/compose/messengercompose.css
+++ b/mail/themes/linux/mail/compose/messengercompose.css
@@ -114,17 +114,17 @@ menulist > .menulist-label-box {
 
 menulist:-moz-locale-dir(rtl) > .menulist-label-box {
   background-position: left;
 }
 
 /* ::::: special toolbar colors ::::: */
 
 #attachmentbucket-sizer {
-  border-top: none;
+  -moz-appearance: none;
 }
 
 #attachments-header-box {
   min-height: 28px;
 }
 
 #attachmentBucketSize {
   color: GrayText;

--- a/mail/themes/linux/mail/mailWindow1.css
+++ b/mail/themes/linux/mail/mailWindow1.css
@@ -79,56 +79,63 @@ treechildren::-moz-tree-cell-text(dummy)
   margin-top: 0;
   /* because of the negative margin needed to make the splitter visible */
   position: relative;
   z-index: 10;
   transition: border-width .3s ease-in;
 }
 
 #folderpane_splitter {
-  border-inline-start: 1px solid ThreeDShadow;
+  border-inline-start: 1px solid var(--splitter-color);
   /* make only the splitter border visible */
   margin-inline-end: -5px;
 }
 
 #folderpane_splitter[state="collapsed"]:hover {
   border-inline-start: 4px solid highlight;
 }
 
 #threadpane-splitter:not([orient="vertical"]) {
-  border-inline-start: 1px solid ThreeDShadow;
+  border-inline-start: 1px solid var(--splitter-color);
   /* make only the splitter border visible */
   margin-inline-end: -5px;
 }
 
 #threadpane-splitter[state="collapsed"]:not([orient="vertical"]) {
   border-inline-start-width: 0;
-  border-inline-end: 1px solid ThreeDShadow;
+  border-inline-end: 1px solid var(--splitter-color);
   margin-inline-start: -5px;
   margin-inline-end: 0;
 }
 
 #threadpane-splitter[state="collapsed"]:not([orient="vertical"]):hover {
   border-inline-end: 4px solid highlight;
 }
 
 #threadpane-splitter,
 #attachment-splitter {
   -moz-appearance: none;
-  border-bottom: 1px solid ThreeDShadow;
   /* splitter grip area */
   height: 5px;
   /* make only the splitter border visible */
   margin-top: -5px;
   /* because of the negative margin needed to make the splitter visible */
   position: relative;
   z-index: 10;
   transition: border-width .3s ease-in;
 }
 
+#threadpane-splitter {
+  border-bottom: 1px solid var(--splitter-color);
+}
+
+#attachment-splitter {
+  border-bottom: 1px solid ThreeDShadow;
+}
+
 #attachment-splitter:not([state="collapsed"]) {
   border-bottom: 1px solid transparent;
 }
 
 #attachment-splitter,
 #threadpane-splitter[state="collapsed"] {
   transition: border-color .3s;
 }

--- a/mail/themes/linux/mail/messageHeader.css
+++ b/mail/themes/linux/mail/messageHeader.css
@@ -7,17 +7,17 @@
   ======================================================================= */
 
 @import url("chrome://messenger/skin/shared/messageHeader.css");
 
 /* ::::: for the entire area ::::: */
 .main-header-area {
   color: WindowText;
   background-color: AppWorkspace;
-  border-bottom: 1px solid ThreeDShadow;
+  border-bottom: 1px solid var(--splitter-color);
   padding: 0.4ex;
 }
 
 /* :::::  message in a tab ::::: */
 #displayDeck[collapsed="true"] + splitter + #messagepaneboxwrapper
 .main-header-area {
   background-image: linear-gradient(rgba(255, 255, 255, 0.3),
                                     rgba(255, 255, 255, 0) 19px);

--- a/mail/themes/linux/mail/messenger.css
+++ b/mail/themes/linux/mail/messenger.css
@@ -35,16 +35,17 @@
 
   --toolbarbutton-checkedhover-backgroundcolor: rgba(200, 200, 200, .5);
   --toolbarbutton-icon-fill-attention: var(--lwt-toolbarbutton-icon-fill-attention, #0a84ff);
 
   --lwt-header-image: none;
   --panel-separator-color: ThreeDShadow;
   --arrowpanel-dimmed: hsla(0, 0%, 80%, .3);
   --arrowpanel-dimmed-further: hsla(0, 0%, 80%, .45);
+  --splitter-color: ThreeDShadow;
   --urlbar-popup-url-color: -moz-nativehyperlinktext;
   --urlbar-popup-action-color: -moz-nativehyperlinktext;
 }
 
 :root:-moz-lwtheme {
   --toolbar-bgcolor: rgba(255,255,255,.4);
   --toolbar-bgimage: none;
 
@@ -54,16 +55,20 @@
 }
 
 :root[lwt-popup-brighttext] {
   --panel-separator-color: rgba(249, 249, 250, .1);
   --arrowpanel-dimmed: rgba(249, 249, 250, .1);
   --arrowpanel-dimmed-further: rgba(249, 249, 250, .15);
 }
 
+:root[lwt-tree] {
+  --splitter-color: var(--sidebar-border-color);
+}
+
 toolbar[brighttext] {
   --toolbarbutton-icon-fill-attention: var(--lwt-toolbarbutton-icon-fill-attention, #45a1ff);
 }
 
 #FindToolbar:-moz-lwtheme,
 .contentTabToolbox:-moz-lwtheme,
 #ab-toolbox > toolbar:-moz-lwtheme,
 .mail-toolbox > toolbar:-moz-lwtheme,

deleted file mode 100644
index 47bc75312415cadc99abe3d1fa4ff312e4135013..0000000000000000000000000000000000000000
GIT binary patch
literal 0
Hc$@<O00001

--- a/mail/themes/osx/jar.mn
+++ b/mail/themes/osx/jar.mn
@@ -10,17 +10,16 @@ classic.jar:
   skin/classic/messenger/dialogs.css                             (mail/dialogs.css)
   skin/classic/messenger/messenger.css                           (mail/messenger.css)
   skin/classic/messenger/primaryToolbar.css                      (mail/primaryToolbar.css)
   skin/classic/messenger/accountCentral.css                      (mail/accountCentral.css)
   skin/classic/messenger/accountCreation.css                     (mail/accountCreation.css)
   skin/classic/messenger/accountManage.css                       (mail/accountManage.css)
   skin/classic/messenger/accountWizard.css                       (mail/accountWizard.css)
 * skin/classic/messenger/chat.css                                (mail/chat.css)
-  skin/classic/messenger/userIcon.png                            (mail/userIcon.png)
   skin/classic/messenger/noise.png                               (mail/noise.png)
 * skin/classic/messenger/imAccounts.css                          (../../components/im/themes/imAccounts.css)
 * skin/classic/messenger/imAccountWizard.css                     (../../components/im/themes/imAccountWizard.css)
   skin/classic/messenger/imMenulist.css                          (../../components/im/themes/imMenulist.css)
 * skin/classic/messenger/imRichlistbox.css                       (../../components/im/themes/imRichlistbox.css)
   skin/classic/messenger/founder.png                             (../../components/im/themes/founder.png)
   skin/classic/messenger/operator.png                            (../../components/im/themes/operator.png)
   skin/classic/messenger/half-operator.png                       (../../components/im/themes/half-operator.png)

--- a/mail/themes/osx/mail/addrbook/addressbook.css
+++ b/mail/themes/osx/mail/addrbook/addressbook.css
@@ -101,28 +101,28 @@
     -moz-image-region: rect(0px 128px 32px 96px);
   }
 }
 
 /* ::::: splitters ::::: */
 
 #dirTree-splitter {
   border-width: 0;
-  border-inline-end: 1px solid #bdbdbd;
+  border-inline-end: 1px solid var(--splitter-color);
   min-width: 0;
   width: 5px;
   background-color: transparent;
   margin-inline-start: -5px;
   position: relative;
   z-index: 10;
 }
 
 #results-splitter {
   border-width: 0;
-  border-top: 1px solid #bdbdbd;
+  border-top: 1px solid var(--splitter-color);
   min-height: 0;
   height: 5px;
   background-color: transparent;
   margin-bottom: -5px;
   position: relative;
   z-index: 10;
 }
 

--- a/mail/themes/osx/mail/attachmentList.css
+++ b/mail/themes/osx/mail/attachmentList.css
@@ -15,37 +15,10 @@
 }
 
 .attachmentcell-name,
 .attachmentcell-size {
   padding-top: 1px;
 }
 
 .attachmentcell-size {
-  color: GrayText;
-}
-
-.attachmentList:focus > .attachmentItem[selected="true"][current="true"] {
-  outline: 1px dotted #F3D982;
-}
-
-.attachmentList:focus > .attachmentItem[current="true"] {
-  outline: 1px dotted;
-  outline-offset: -1px;
+  color: #999;
 }
-
-.attachmentItem[selected="true"] {
-  background-color: -moz-CellHighlight;
-  color: -moz-CellHighlightText;
-}
-
-.attachmentList:focus > .attachmentItem[selected="true"] {
-  background-color: Highlight;
-  color: HighlightText;
-}
-
-.attachmentItem[selected="true"] .attachmentcell-size {
-  color: -moz-CellHighlightText;
-}
-
-.attachmentList:focus >.attachmentItem[selected="true"] .attachmentcell-size {
-  color: HighlightText;
-}

--- a/mail/themes/osx/mail/chat.css
+++ b/mail/themes/osx/mail/chat.css
@@ -10,17 +10,17 @@
 :root:not([lwt-tree]) #chatPanel {
   -moz-appearance: -moz-mac-source-list;
   -moz-font-smoothing-background-color: -moz-mac-source-list;
 }
 
 #chatTabPanel {
   --imbox-selected-text-color: -moz-FieldText;
   --imbox-selected-background-color: -moz-Field;
-  --imbox-selected-border-color: #bdbdbd;
+  --imbox-selected-border-color: var(--splitter-color);
   --imgroup-selected-background-color: ThreeDLightShadow;
 }
 
 #contactlistbox {
   background: transparent;
   -moz-appearance: none;
 }
 
@@ -79,17 +79,16 @@
 #chat-status-selector:-moz-lwtheme > .statusMessageToolbarItem[editing] {
   box-shadow: 0 0 0 1px var(--toolbar-field-focus-border-color) inset,
               0 0 0 1px var(--toolbar-field-focus-border-color);
 }
 
 /* Adaptation of #folderpane_splitter */
 #listSplitter,
 #contextSplitter {
-  background-image: none;
   min-width: 5px;
 }
 
 .conv-status-container {
   border-bottom-color: #8B8B8B;
 }
 
 .startChatBubble > .button-box > .button-icon,
@@ -97,16 +96,21 @@
   margin-inline-start: 0;
 }
 
 /* Set a background color to avoid lightweight theme backgrounds */
 #contextPane {
   background-color: #fff;
 }
 
+.statusMessage[editing] {
+  color: -moz-dialogtext;
+  margin: 29px 0 -1px -4px;
+}
+
 #displayNameAndstatusMessageStack #statusMessage {
   margin: 32px 0 0;
   min-height: 16px;
 }
 
 #displayNameAndstatusMessageStack #statusMessage[editing] {
   margin: 29px 2px 0 -4px;
 }

--- a/mail/themes/osx/mail/compose/messengercompose.css
+++ b/mail/themes/osx/mail/compose/messengercompose.css
@@ -21,18 +21,17 @@
   border-bottom: 1px solid var(--chrome-content-separator-color);
 }
 
 #attachments-box[empty] > #attachmentBucket:focus {
   box-shadow: 0 0 1.5px 1px -moz-mac-focusring inset;
 }
 
 #attachmentBucket .attachmentItem {
-  border-top: 1px solid transparent;
-  border-bottom: 1px solid #fff;
+  border: 1px solid transparent;
 }
 
 #attachmentBucket .attachmentItem[dropOn="top"] {
   border-top-color: #000;
   outline-color: transparent;
 }
 
 #attachmentBucket .attachmentItem[dropOn="bottom"] {
@@ -78,16 +77,20 @@ toolbar[nowindowdrag="true"] {
   box-shadow: 0 2px 4px rgba(0, 0, 0, 0.6) inset;
   background-color: rgb(242, 242, 242);
 }
 
 #composeContentBox:-moz-window-inactive {
   box-shadow: 0 1px 2px rgba(0, 0, 0, 0.2) inset;
 }
 
+#headers-box {
+  padding-bottom: 3px;
+}
+
 #MsgHeadersToolbar {
   color: -moz-DialogText;
   text-shadow: none;
   background-image: url("chrome://messenger/skin/noise.png");
   border-bottom: 0 solid;
 }
 
 #addresses-box {
@@ -141,34 +144,28 @@ toolbar[nowindowdrag="true"] {
 #msgIdentityPopup {
   margin-inline-start: initial;
 }
 
 #addresses-box {
   margin: 4px 6px;
 }
 
-#attachmentbucket-sizer {
-  border-top: none;
-  border-bottom: none;
-  height: 7px;
-}
-
 #attachments-header-box {
   min-height: 28px;
 }
 
 #attachmentBucketCount {
   padding-top: 2px;
 }
 
 #attachmentBucketSize {
   padding-top: 2px;
   padding-inline-end: 2px;
-  color: GrayText;
+  color: #999;
 }
 
 #attachmentBucketCloseButton {
   padding: 0 1px;
   margin-top: 1px;
 }
 
 /* ::::: attachment reminder ::::: */
@@ -336,25 +333,31 @@ textbox.textbox-addressingWidget:hover {
   margin: 1px 1px 0 !important;
   text-align: end;
 }
 
 .aw-menulist > .menulist-dropmarker {
   display: none;
 }
 
+.menulist-description {
+  color: #999;
+}
+
 /* ::::: compose toolbar sizer ::::: */
 
 #compose-toolbar-sizer {
   position: relative;
-  margin-top: -2px;
-  min-height: 7px;
-  background-image: url("chrome://messenger/skin/messengercompose/osx-noise.png");
-  background-color: rgb(242, 242, 242);
-  border-bottom: 1px solid #DCDCDC;
+  z-index: 10;
+  min-height: 0;
+  height: 5px;
+  margin-top: -5px;
+  border-top-width: 0;
+  border-bottom-color: var(--splitter-color);
+  background-color: transparent;
 }
 
 /* ::::: format toolbar ::::: */
 
 #FormatToolbar {
   border-bottom: none;
   background-image: url("chrome://messenger/skin/messengercompose/osx-noise.png");
   background-color: rgb(242, 242, 242) !important;
@@ -1014,19 +1017,24 @@ toolbarbutton.toolbarbutton-1 > .toolbar
 }
 
 #sidebar-box {
   -moz-appearance: -moz-mac-source-list;
   -moz-font-smoothing-background-color: -moz-mac-source-list;
 }
 
 #sidebar-splitter {
-  border-right: 1px solid #8e8e8e;
-  border-left: 1px solid #bebebe;
-  background-color: #ececec;
+  border-inline-end-width: 0;
+  border-inline-start: 1px solid var(--splitter-color);
+  min-width: 0;
+  width: 5px;
+  background-color: transparent;
+  margin-inline-end: -5px;
+  position: relative;
+  z-index: 10;
 }
 
 #sidebar-title {
   font: icon;
   color: #000;
 }
 
 #searchInput #sidebar {

--- a/mail/themes/osx/mail/mailWindow1.css
+++ b/mail/themes/osx/mail/mailWindow1.css
@@ -109,86 +109,82 @@ treechildren::-moz-tree-row(dummy, focus
 
 #messagepanebox {
   background-color: #FFFFFF;
   -moz-appearance: none;
 }
 
 /* ..... splitter adjustments ..... */
 
-splitter {
-  background-color: transparent;
-  width: 7px;
-  min-width: 7px;
-  min-height: 7px;
-}
-
-#threadpane-splitter {
-  height: 8px !important;
-  min-height: 8px;
-  background-image: url("chrome://messenger/skin/icons/vertical-threadpane-splitter-bg.gif");
-  background-repeat: repeat-y;
-  border-inline-start: 1px solid #A6A6A6;
-  border-inline-end: 1px solid #8C8C8C;
-}
-
-#threadpane-splitter:-moz-locale-dir(rtl) {
-  background-image: url("chrome://messenger/skin/icons/vertical-threadpane-splitter-bg-rtl.gif");
-}
-
-/* The orient="vertical" isn't which direction the splitter itself runs, it's
-   actually which way its parent lays out its children, so when it's vertical,
-   the splitter is a horizontal bar. */
-#threadpane-splitter[orient="vertical"] {
-  background-image: url("chrome://messenger/skin/icons/threadpane-splitter-bg.gif");
-  background-repeat: repeat-x;
-  border-top: 1px solid #A6A6A6;
-  border-bottom: 1px solid #8C8C8C;
-  border-inline-start-width: 0;
-  border-inline-end-width: 0;
-}
-
-#threadpane-splitter[state="collapsed"] {
-  border-bottom-width: 0;
-  border-inline-end: 0;
-}
-
 #folderpane_splitter,
 #threadpane-splitter:not([orient="vertical"]) {
-  background-image: none;
-  /* splitter grip area */
+  border-width: 0;
+  min-width: 0;
   width: 5px;
-  min-width: 5px;
-  /* because of the negative margin needed to make the splitter visible */
+  background-color: transparent;
+  margin-top: 0;
   position: relative;
   z-index: 10;
   transition: border-width .3s ease-in;
 }
 
 #folderpane_splitter {
-  border-inline-start: 1px solid #bdbdbd;
+  border-inline-start: 1px solid var(--splitter-color);
   /* make only the splitter border visible */
   margin-inline-end: -4px;
 }
 
 #folderpane_splitter[state="collapsed"]:hover {
   border-inline-start: 4px solid highlight;
 }
 
 #threadpane-splitter:not([orient="vertical"]) {
-  border-inline-start-style: none;
-  border-inline-end: 1px solid #bdbdbd;
+  border-inline-end: 1px solid var(--splitter-color);
   /* make only the splitter border visible */
   margin-inline-start: -4px;
 }
 
 #threadpane-splitter[state="collapsed"]:not([orient="vertical"]):hover {
   border-inline-end: 4px solid highlight;
 }
 
+#threadpane-splitter,
+#attachment-splitter {
+  border-width: 0;
+  min-height: 0;
+  height: 5px;
+  background-color: transparent;
+  margin-top: -5px;
+  position: relative;
+  z-index: 10;
+  transition: border-width .3s ease-in;
+}
+
+#threadpane-splitter {
+  border-bottom: 1px solid var(--splitter-color);
+}
+
+#attachment-splitter {
+  border-bottom: 1px solid #bdbdbd;
+}
+
+#attachment-splitter:not([state="collapsed"]) {
+  border-bottom: 1px solid transparent;
+}
+
+#attachment-splitter,
+#threadpane-splitter[state="collapsed"] {
+  transition: border-color .3s;
+}
+
+#threadpane-splitter[state="collapsed"]:hover,
+#attachment-splitter[state="collapsed"]:hover {
+  border-bottom: 4px solid highlight;
+}
+
 /* ..... status bar adjustments ..... */
 
 #quotaMeter {
   -moz-appearance: none;
 }
 
 .tabmail-tab[type="message"][IsFeedMessage] {
   list-style-image: url("chrome://messenger-newsblog/skin/rss-feed.png");

--- a/mail/themes/osx/mail/messageHeader.css
+++ b/mail/themes/osx/mail/messageHeader.css
@@ -6,17 +6,17 @@
   == Styles for the header toolbars of a mail message.
   ======================================================================= */
 
 @import url("chrome://messenger/skin/shared/messageHeader.css");
 
 /* ::::: for the entire area ::::: */
 .main-header-area {
   color: #2E3436; /* Aluminium 6 */
-  border-bottom:1px solid #BFBFBF;
+  border-bottom:1px solid var(--splitter-color);
   padding: 0.6ex;
 }
 
 #displayDeck:not([collapsed="true"]) + #threadpane-splitter + #messagepanebox .main-header-area {
   background: linear-gradient(#E4E4E4, #FFFFFF 5px);
 }
 
 /* ::::: msg header toolbars ::::: */
@@ -33,17 +33,17 @@
 #expandedBoxSpacer {
   display: block;
   height: 5px;
 }
 
 /* ::::: attachment view ::::: */
 
 #attachmentList {
-  margin: 0px;
+  margin: 0;
   background-color: -moz-Field;
   color: -moz-FieldText;
 }
 
 #attachmentToggle {
   -moz-appearance: treetwisty;
   -moz-user-focus: normal;
 }
@@ -86,22 +86,16 @@
   border-top: 1px solid ThreeDShadow;
 }
 
 #attachmentBar {
   background-color: #fff;
   color: -moz-dialogtext;
 }
 
-#attachment-splitter {
-  min-height: 7px;
-  border-top: 1px solid #C8C8C8;
-  background-color: #E6E6E6;
-}
-
 /* ::::: attachment list ::::: */
 
 .attachmentcell-name,
 .attachmentcell-size {
   padding-top: 1px;
 }
 
 .attachmentcell-size {

--- a/mail/themes/osx/mail/messenger.css
+++ b/mail/themes/osx/mail/messenger.css
@@ -43,16 +43,17 @@
   --toolbarbutton-inactive-boxshadow: 0 1px 0 hsla(0, 0%, 0%, .05) inset;
   --toolbarbutton-checkedhover-backgroundcolor: hsla(0, 0%, 0%, .09);
   --toolbarbutton-icon-fill-attention: var(--lwt-toolbarbutton-icon-fill-attention, #0a84ff);
 
   --lwt-header-image: none;
   --panel-separator-color: hsla(210, 4%, 10%, .14);
   --arrowpanel-dimmed: hsla(0, 0%, 80%, .3);
   --arrowpanel-dimmed-further: hsla(0, 0%, 80%, .45);
+  --splitter-color: #bdbdbd;
   --urlbar-popup-url-color: hsl(210, 77%, 47%);
   --urlbar-popup-action-color: hsl(178, 100%, 28%);
 }
 
 :root:-moz-window-inactive {
   --toolbar-bgcolor: -moz-mac-chrome-inactive;
 }
 
@@ -64,16 +65,20 @@
 }
 
 :root[lwt-popup-brighttext] {
   --panel-separator-color: rgba(249, 249, 250, .1);
   --arrowpanel-dimmed: rgba(249, 249, 250, .1);
   --arrowpanel-dimmed-further: rgba(249, 249, 250, .15);
 }
 
+:root[lwt-tree] {
+  --splitter-color: var(--sidebar-border-color);
+}
+
 toolbar[brighttext] {
   --toolbarbutton-icon-fill-attention: var(--lwt-toolbarbutton-icon-fill-attention, #45a1ff);
 }
 
 #FindToolbar:-moz-lwtheme,
 .contentTabToolbox:-moz-lwtheme,
 #ab-toolbox > toolbar:-moz-lwtheme,
 .mail-toolbox > toolbar:-moz-lwtheme,

deleted file mode 100644
index 47bc75312415cadc99abe3d1fa4ff312e4135013..0000000000000000000000000000000000000000
GIT binary patch
literal 0
Hc$@<O00001

--- a/mail/themes/shared/jar.inc.mn
+++ b/mail/themes/shared/jar.inc.mn
@@ -80,16 +80,17 @@
   skin/classic/messenger/icons/star.svg                       (../shared/mail/icons/star.svg)
   skin/classic/messenger/icons/starred.svg                    (../shared/mail/icons/starred.svg)
   skin/classic/messenger/icons/sticky.svg                     (../shared/mail/icons/sticky.svg)
   skin/classic/messenger/icons/stop.svg                       (../shared/mail/icons/stop.svg)
   skin/classic/messenger/icons/tag.svg                        (../shared/mail/icons/tag.svg)
   skin/classic/messenger/icons/thread-col.svg                 (../shared/mail/icons/thread-col.svg)
   skin/classic/messenger/icons/timeline.svg                   (../shared/mail/icons/timeline.svg)
   skin/classic/messenger/icons/toolbarbutton-arrow.svg        (../shared/mail/icons/toolbarbutton-arrow.svg)
+  skin/classic/messenger/icons/userIcon.svg                   (../shared/mail/icons/userIcon.svg)
   skin/classic/messenger/icons/waiting.svg                    (../shared/mail/icons/waiting.svg)
   skin/classic/messenger/shared/accountCreation.css           (../shared/mail/accountCreation.css)
   skin/classic/messenger/shared/accountProvisioner.css        (../shared/mail/accountProvisioner.css)
   skin/classic/messenger/shared/addressbook.css               (../shared/mail/addressbook.css)
   skin/classic/messenger/shared/compacttheme.css              (../shared/mail/compacttheme.css)
   skin/classic/messenger/shared/in-content/dialog.css         (../shared/mail/incontentprefs/dialog.css)
   skin/classic/messenger/shared/in-content/aboutPreferences.css (../shared/mail/incontentprefs/aboutPreferences.css)
   skin/classic/messenger/shared/in-content/account.svg        (../shared/mail/incontentprefs/account.svg)

new file mode 100644
--- /dev/null
+++ b/mail/themes/shared/mail/icons/userIcon.svg
@@ -0,0 +1,6 @@
+<!-- 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/. -->
+<svg width="48" height="48" xmlns="http://www.w3.org/2000/svg" fill="context-fill" fill-opacity="context-fill-opacity">
+  <path d="M0 43.57c0-7.53 1.87-10.19 8.27-13.29 9.12-3.55 11.08-3.55 7.94-10.19-2.98-3.1-2.1-13.3.33-16.4C17.73 1.92 20.29.6 22.98.15c3.73-.44 5 0 7.56 2.66 2.57 2.21 3.08 3.99 3.08 8.86 0 3.1-.33 6.2-.89 6.2-.54.45-1.32 2.22-1.61 3.55-2.09 4.87 1.76 6.64 8.31 8.86 5.51 1.77 7.35 3.99 8.16 11.52L48 48H0z"/>
+</svg>

--- a/mail/themes/shared/mail/messengercompose.css
+++ b/mail/themes/shared/mail/messengercompose.css
@@ -76,22 +76,79 @@
     list-style-image: var(--webextension-menupanel-image-2x-dark, inherit);
   }
 
   .webextension-menuitem {
     list-style-image: var(--webextension-menuitem-image-2x, inherit) !important;
   }
 }
 
+#attachmentbucket-sizer {
+  position: relative;
+  z-index: 10;
+  min-width: 0;
+  width: 5px;
+  margin-inline-end: -4px;
+  border-inline-end-width: 0;
+  border-inline-start: 1px solid var(--splitter-color);
+  background-color: transparent;
+}
+
+#attachmentbucket-sizer[state="collapsed"] {
+  border-inline-start-color: transparent;
+  cursor: default;
+}
+
 #attachmentBucket {
+  -moz-appearance: none;
+  border-top: 1px solid var(--splitter-color); /* The same color as the splitters */
+  border-bottom: 1px solid var(--splitter-color);
   width: 15em;
   min-width: 15em;
   padding: 1px;
 }
 
+:root[lwt-tree] #attachmentBucket {
+  background-color: var(--sidebar-background-color);
+  color: var(--sidebar-text-color);
+}
+
+:root[lwt-tree] #attachmentBucket {
+  scrollbar-color: rgba(204,204,204,.5) rgba(230,230,235,.5);
+}
+
+:root[lwt-tree-brighttext] #attachmentBucket {
+  scrollbar-color: rgba(249,249,250,.4) rgba(20,20,25,.3);
+}
+
+:root[lwt-tree] #attachmentBucket > .attachmentItem {
+  color: var(--sidebar-text-color) !important;
+}
+
+:root[lwt-tree] #attachmentBucket > .attachmentItem[selected="true"] {
+  background: var(--sidebar-highlight-background-color, hsla(0,0%,80%,.6));
+  border-color: var(--sidebar-highlight-background-color, hsla(0,0%,80%,.6));
+  color: var(--sidebar-highlight-text-color, var(--sidebar-text-color)) !important;
+}
+
+:root[lwt-tree-brighttext] #attachmentBucket > .attachmentItem[selected="true"] {
+  background: var(--sidebar-highlight-background-color, rgba(249,249,250,.1));
+  border-color: var(--sidebar-highlight-background-color, rgba(249,249,250,.1));
+}
+
+:root[lwt-tree] #attachmentBucket[seltype="multiple"]:focus >
+  .attachmentItem[current="true"] {
+  outline: 1px solid var(--sidebar-highlight-background-color, hsla(0,0%,80%,.6));
+}
+
+:root[lwt-tree-brighttext] #attachmentBucket[seltype="multiple"]:focus >
+  .attachmentItem[current="true"] {
+  outline: 1px solid var(--sidebar-highlight-background-color, rgba(249,249,250,.1));
+}
+
 #attachments-box[collapsed="true"]:not([empty="true"]) + #attachments-placeholder-box {
   display: -moz-box;
   width: 32px;
   background: url("chrome://messenger/skin/icons/attach.svg") center / 32px no-repeat;
   -moz-context-properties: fill;
   fill: currentColor;
 }
 

--- a/mail/themes/windows/jar.mn
+++ b/mail/themes/windows/jar.mn
@@ -6,17 +6,16 @@ classic.jar:
 % skin messenger classic/1.0 %skin/classic/messenger/
 #include ../shared/jar.inc.mn
   skin/classic/messenger/primaryToolbar.css                   (mail/primaryToolbar.css)
   skin/classic/messenger/accountCentral.css                   (mail/accountCentral.css)
   skin/classic/messenger/accountCreation.css                  (mail/accountCreation.css)
   skin/classic/messenger/accountManage.css                    (mail/accountManage.css)
   skin/classic/messenger/accountWizard.css                    (mail/accountWizard.css)
 * skin/classic/messenger/chat.css                             (mail/chat.css)
-  skin/classic/messenger/userIcon.png                         (mail/userIcon.png)
 * skin/classic/messenger/imAccounts.css                       (../../components/im/themes/imAccounts.css)
 * skin/classic/messenger/imAccountWizard.css                  (../../components/im/themes/imAccountWizard.css)
   skin/classic/messenger/imMenulist.css                       (../../components/im/themes/imMenulist.css)
 * skin/classic/messenger/imRichlistbox.css                    (../../components/im/themes/imRichlistbox.css)
   skin/classic/messenger/founder.png                          (../../components/im/themes/founder.png)
   skin/classic/messenger/operator.png                         (../../components/im/themes/operator.png)
   skin/classic/messenger/half-operator.png                    (../../components/im/themes/half-operator.png)
   skin/classic/messenger/voice.png                            (../../components/im/themes/voice.png)

--- a/mail/themes/windows/mail/addrbook/addressbook.css
+++ b/mail/themes/windows/mail/addrbook/addressbook.css
@@ -140,28 +140,28 @@ toolbox > toolbar:last-of-type {
 #dirTree {
   border-inline-end: 1px solid transparent;
 }
 
 /* ::::: splitters ::::: */
 
 #dirTree-splitter {
   border-width: 0;
-  border-inline-end: 1px solid #a9b7c9;
+  border-inline-end: 1px solid var(--splitter-color);
   min-width: 0;
   width: 3px;
   background-color: transparent;
   margin-inline-start: -3px;
   position: relative;
   z-index: 10;
 }
 
 #results-splitter {
   border-width: 0;
-  border-top: 1px solid #a9b7c9;
+  border-top: 1px solid var(--splitter-color);
   min-height: 0;
   height: 3px;
   background-color: transparent;
   margin-bottom: -3px;
   position: relative;
   z-index: 10;
 }
 

--- a/mail/themes/windows/mail/attachmentList.css
+++ b/mail/themes/windows/mail/attachmentList.css
@@ -16,51 +16,18 @@
 .attachmentcell-size {
   padding-top: 1px;
 }
 
 .attachmentcell-size {
   color: GrayText;
 }
 
-.attachmentList[orient="horizontal"] > .attachmentItem {
-  pointer-events: none;
-}
-
-.attachmentList[orient="horizontal"] .attachmentcell-icon,
-.attachmentList[orient="horizontal"] .attachmentcell-nameselection {
-  pointer-events: auto;
-}
-
-.attachmentList:focus > .attachmentItem[selected="true"][current="true"] .attachmentcell-nameselection {
-  outline: 1px dotted #F3D982;
-}
-
-.attachmentList:focus > .attachmentItem[current="true"] .attachmentcell-nameselection {
-  outline: 1px dotted;
-  outline-offset: -1px;
-}
-
-.attachmentItem[selected="true"] .attachmentcell-nameselection {
-  background-color: -moz-CellHighlight;
-  color: -moz-CellHighlightText;
-}
-
-.attachmentList:focus > .attachmentItem[selected="true"] .attachmentcell-nameselection {
-  background-color: Highlight;
-  color: HighlightText;
-}
-
-.attachmentList:focus > .attachmentItem[selected="true"] .attachmentcell-icon {
-  filter: url("chrome://messenger/skin/imageFilters.svg#selected-focus");
-}
-
 @media (-moz-windows-default-theme) {
   .attachmentItem {
-    pointer-events: auto !important;
     border: 1px solid transparent;
     color: -moz-FieldText !important;
     background-color: transparent;
     background-repeat: no-repeat;
     background-size: 100% 100%;
     padding: 1px;
   }
 
@@ -69,26 +36,16 @@
     margin-bottom: 1px;
   }
 
   .attachmentList[orient="horizontal"] > .attachmentItem {
     margin-top: 1px;
     margin-inline-start: 1px;
   }
 
-  .attachmentcell-nameselection {
-    outline: none !important;
-    background-color: inherit !important;
-    color: inherit !important;
-  }
-
-  .attachmentcell-icon {
-    filter: none !important;
-  }
-
   .attachmentcell-name, .attachmentcell-size {
     margin: 0 4px;
   }
 
   @media (-moz-os-version: windows-win7) {
     .attachmentItem {
       border-radius: 3px;
     }

--- a/mail/themes/windows/mail/chat.css
+++ b/mail/themes/windows/mail/chat.css
@@ -4,17 +4,17 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 %endif
 
 %include ../../../components/im/themes/chat.css
 
 #chatTabPanel {
   --imbox-selected-text-color: -moz-FieldText;
   --imbox-selected-background-color: -moz-Field;
-  --imbox-selected-border-color: #a9b7c9;
+  --imbox-selected-border-color: var(--splitter-color);
   --imgroup-selected-background-color: ThreeDLightShadow;
 }
 
 /* Adaptation from #folderTree */
 :root:not([lwt-tree]) #listPaneBox {
   -moz-appearance:  none;
   background-color: -moz-Field;
   color: -moz-FieldText;
@@ -25,41 +25,32 @@
   -moz-appearance: none !important;
   border: none;
 }
 
 #conversationsDeck {
   background: var(--imbox-selected-background-color);
 }
 
-.conv-messages {
-  border-top: 0;
-  border-bottom: 0;
-}
-
 .conv-textbox {
   -moz-appearance: none;
   /* Right/left margins so the borders show up on all sides. */
   margin: 0 1px 0 1px;
 }
 
 .conv-counter[value^="-"] {
   margin-inline-end: 2px;
   padding-inline-end: 4px;
 }
 
 #contextPane {
   background-color: -moz-field;
   color: -moz-fieldtext;
 }
 
-.conv-top-info {
-  background: transparent;
-}
-
 .userIcon {
   border-width: 0px;
 }
 
 #logTree,
 .conv-nicklist {
   -moz-appearance: none;
   border: none;
@@ -71,16 +62,21 @@
   -moz-appearance: none;
   margin: 0;
   padding-top: 2px;
   padding-bottom: 2px;
   border-bottom: 1px solid ThreeDShadow;
   background-color: -moz-Dialog;
 }
 
+.statusMessage[editing] {
+  color: -moz-dialogtext;
+  margin: 28px 0 -1px -2px;
+}
+
 #displayNameAndstatusMessageStack #statusMessage {
   margin: 32px 0 0;
 }
 
 #displayNameAndstatusMessageStack  #statusMessage[editing] {
   margin: 30px 0 1px -2px;
 }
 
@@ -132,25 +128,16 @@
   }
 
   #chat-status-selector:not(:-moz-lwtheme) > .statusMessageToolbarItem[editing] {
     border-color: hsla(206, 100%, 60%, .65) hsla(206, 100%, 55%, .65)
                   hsla(206, 100%, 50%, .65);
     background-color: -moz-field;
   }
 
-  .splitter[orient="vertical"],
-  #logsSplitter {
-    border-bottom-color: #a9b7c9;
-  }
-
-  #contextSplitter {
-    border-inline-end-color: #a9b7c9;
-  }
-
   richlistitem[selected] > label,
   #nicklist:focus > richlistitem[inactive][selected] > label {
     color: -moz-dialogtext !important;
   }
 }
 
 @media (-moz-os-version: windows-win7) and (-moz-windows-default-theme) {
   :root:not([lwt-tree]) #listPaneBox {

--- a/mail/themes/windows/mail/compose/messengercompose.css
+++ b/mail/themes/windows/mail/compose/messengercompose.css
@@ -7,19 +7,16 @@
   ======================================================================= */
 
 @import url("chrome://messenger/skin/");
 @import url("chrome://messenger/skin/shared/messengercompose.css");
 
 @namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
 
 #attachmentBucket {
-  -moz-appearance: none;
-  border-top: 1px solid #a9b7c9; /* The same color as the splitters */
-  border-bottom: 1px solid #a9b7c9;
   background-color: -moz-Field;
   color: -moz-FieldText;
 }
 
 #attachments-box[empty] > #attachmentBucket:focus {
   box-shadow: 0 0 1px Highlight inset, 0 0 1px Highlight inset;
 }
 
@@ -36,16 +33,21 @@
 #attachmentBucket .attachmentItem[dropOn="top"] {
   border-top-color: Highlight;
 }
 
 #attachmentBucket .attachmentItem[dropOn="bottom"] {
   border-bottom-color: Highlight;
 }
 
+:root[lwt-tree] #attachmentBucket > .attachmentItem:hover {
+  background-color: hsla(0,0%,50%,.15);
+  border-color: transparent;
+}
+
 /* ::::: special toolbar colors ::::: */
 
 @media (-moz-os-version: windows-win10) and (-moz-windows-default-theme) {
   #menubar-items > #mail-menubar > menu {
     -moz-appearance: none;
     border-style: none;
   }
 
@@ -75,17 +77,16 @@
 
 #composeContentBox:-moz-window-inactive {
   box-shadow: 0 1px 2px rgba(0, 0, 0, 0.05) inset;
 }
 
 #headers-box {
   -moz-appearance: none;
   padding-bottom: 2px;
-  border-bottom: 1px solid ThreeDShadow;
 }
 
 #MsgHeadersToolbar {
   color: -moz-DialogText;
   text-shadow: none;
 }
 
 #msgheaderstoolbar-box {
@@ -611,51 +612,33 @@ toolbar:not(:-moz-lwtheme) {
   }
 }
 
 .findbar-container {
   padding-top: 2px;
   padding-bottom: 2px;
 }
 
-/* ::::: special toolbar colors ::::: */
-
-#attachmentbucket-sizer {
-  position: relative;
-  z-index: 10;
-  min-width: 0;
-  width: 5px;
-  margin-inline-end: -4px;
-  border-inline-end-width: 0;
-  border-inline-start: 1px solid #a9b7c9;
-  background-color: transparent;
-}
-
-#attachmentbucket-sizer[state="collapsed"] {
-  border-inline-start-color: transparent;
-  cursor: default;
-}
-
 #attachments-header-box {
   min-height: 26px;
 }
 
 #attachmentBucketSize {
   padding-inline-end: 2px;
   color: GrayText;
 }
 
 #compose-toolbar-sizer {
   position: relative;
   z-index: 10;
   min-height: 0;
   height: 5px;
   margin-top: -5px;
   border-top-width: 0;
-  border-bottom-width: 0;
+  border-bottom-color: var(--splitter-color);
   background-color: transparent;
 }
 
 #subjectLabel {
   margin-top: 0;
 }
 
 /* ::::: autocomplete icons ::::: */
@@ -791,30 +774,26 @@ toolbar:not(:-moz-lwtheme) {
 }
 
 #sidebar {
   background-color: -moz-Dialog;
 }
 
 #sidebar-splitter {
   border-inline-end-width: 0;
-  border-inline-start: 1px solid #a9b7c9;
+  border-inline-start: 1px solid var(--splitter-color);
   min-width: 0;
   width: 5px;
   background-color: transparent;
   margin-inline-end: -5px;
   position: relative;
   z-index: 10;
 }
 
 @media (-moz-os-version: windows-win7) and (-moz-windows-default-theme) {
-  #headers-box {
-    border-bottom-color: #a9b7c9;
-  }
-
   findbar {
     background-color: #eef3fa;
   }
 
   menulist {
     border-radius: 2px;
   }
 
@@ -847,16 +826,12 @@ toolbar:not(:-moz-lwtheme) {
 }
 
 @media (-moz-windows-glass) {
   #compose-toolbox:not(:-moz-lwtheme) {
     color: black;
     text-shadow: 0 0 .7em white, 0 0 .7em white, 0 1px 0 rgba(255, 255, 255, .4);
   }
 
-  #headers-box {
-    border-bottom-color: #aabccf;
-  }
-
   #composeContentBox {
     background-image: url("chrome://messenger/skin/messengercompose/noise.png");
   }
 }

--- a/mail/themes/windows/mail/mailWindow1.css
+++ b/mail/themes/windows/mail/mailWindow1.css
@@ -440,48 +440,55 @@ treechildren::-moz-tree-cell-text(dummy)
   background-color: transparent;
   margin-top: 0;
   position: relative;
   z-index: 10;
   transition: border-width .3s ease-in;
 }
 
 #folderpane_splitter {
-  border-inline-start: 1px solid #a9b7c9;
+  border-inline-start: 1px solid var(--splitter-color);
   /* make only the splitter border visible */
   margin-inline-end: -4px;
 }
 
 #folderpane_splitter[state="collapsed"]:hover {
   border-inline-start: 4px solid highlight;
 }
 
 #threadpane-splitter:not([orient="vertical"]) {
-  border-inline-end: 1px solid #a9b7c9;
+  border-inline-end: 1px solid var(--splitter-color);
   /* make only the splitter border visible */
   margin-inline-start: -4px;
 }
 
 #threadpane-splitter[state="collapsed"]:not([orient="vertical"]):hover {
   border-inline-end: 4px solid highlight;
 }
 
 #threadpane-splitter,
 #attachment-splitter {
   border-width: 0;
-  border-bottom: 1px solid #a9b7c9;
   min-height: 0;
   height: 5px;
   background-color: transparent;
   margin-top: -5px;
   position: relative;
   z-index: 10;
   transition: border-width .3s ease-in;
 }
 
+#threadpane-splitter {
+  border-bottom: 1px solid var(--splitter-color);
+}
+
+#attachment-splitter {
+  border-bottom: 1px solid #a9b7c9;
+}
+
 #attachment-splitter:not([state="collapsed"]) {
   border-bottom: 1px solid transparent;
 }
 
 #attachment-splitter,
 #threadpane-splitter[state="collapsed"] {
   transition: border-color .3s;
 }

--- a/mail/themes/windows/mail/messageHeader.css
+++ b/mail/themes/windows/mail/messageHeader.css
@@ -8,17 +8,17 @@
 
 @import url("chrome://messenger/skin/shared/messageHeader.css");
 
 /* ::::: for the entire area ::::: */
 .main-header-area {
   color: WindowText;
   background-color: ButtonFace;
   padding: 0.4ex;
-  border-bottom: 1px solid #a9b7c9; /* The same color as the splitters */
+  border-bottom: 1px solid var(--splitter-color); /* The same color as the splitters */
 }
 
 /* ::::: msg header toolbars ::::: */
 
 #expandedHeaderView[show_header_mode="all"] {
   overflow-y: auto;
   overflow-x: hidden;
   max-height: 14em;

--- a/mail/themes/windows/mail/messenger.css
+++ b/mail/themes/windows/mail/messenger.css
@@ -36,31 +36,33 @@
 
   --toolbarbutton-checkedhover-backgroundcolor: rgba(0, 0, 0, .2);
   --toolbarbutton-icon-fill-attention: var(--lwt-toolbarbutton-icon-fill-attention, #0a84ff);
 
   --lwt-header-image: none;
   --panel-separator-color: ThreeDLightShadow;
   --arrowpanel-dimmed: hsla(0, 0%, 80%, .3);
   --arrowpanel-dimmed-further: hsla(0, 0%, 80%, .45);
+  --splitter-color: ThreeDShadow;
 }
 
 @media (-moz-windows-default-theme) {
   :root {
     --tabs-border-color: rgba(0,0,0,.3);
     --tabline-color: #0a84ff;
 
     --toolbar-non-lwt-bgcolor: #f9f9fa;
     --toolbar-non-lwt-textcolor: #0c0c0d;
     --toolbar-non-lwt-bgimage: none;
 
     --panel-separator-color: hsla(210,4%,10%,.14);
 
     --urlbar-popup-url-color: hsl(210, 77%, 47%);
     --urlbar-popup-action-color: hsl(178, 100%, 28%);
+    --splitter-color: #a9b7c9;
   }
 }
 
 @media (-moz-windows-default-theme: 0) {
   :root {
     --urlbar-popup-url-color: -moz-nativehyperlinktext;
     --urlbar-popup-action-color: -moz-nativehyperlinktext;
   }
@@ -78,16 +80,20 @@
 }
 
 :root[lwt-popup-brighttext] {
   --panel-separator-color: rgba(249, 249, 250, .1);
   --arrowpanel-dimmed: rgba(249, 249, 250, .1);
   --arrowpanel-dimmed-further: rgba(249, 249, 250, .15);
 }
 
+:root[lwt-tree] {
+  --splitter-color: var(--sidebar-border-color);
+}
+
 toolbar[brighttext] {
   --toolbarbutton-icon-fill-attention: var(--lwt-toolbarbutton-icon-fill-attention, #45a1ff);
 }
 
 #FindToolbar:-moz-lwtheme,
 .contentTabToolbox:-moz-lwtheme,
 #ab-toolbox > toolbar:-moz-lwtheme,
 .mail-toolbox > toolbar:-moz-lwtheme,

deleted file mode 100644
index 47bc75312415cadc99abe3d1fa4ff312e4135013..0000000000000000000000000000000000000000
GIT binary patch
literal 0
Hc$@<O00001