fix(themes): Fix linter issues and relink images

internal_packages/ui-darkside/styles/darkside.less

@@ -49,7 +49,7 @@
 // Make sidebar and corresponding toolbar match
 .column-RootSidebar,
 .account-sidebar,
-.sheet-toolbar-container [data-column='0'] {
+.sheet-toolbar-container > div:nth-child(1) {
   height: 100%;
   background-color: @sidebar;
   // If NOT Retina display, subpixel-antialias fonts instead
@@ -79,7 +79,7 @@
 //====================================================
 
 // Match alignment for toolbar above sidebar
-.sheet-toolbar-container [data-column='0'] {
+.sheet-toolbar-container > div:nth-child(1) {
   padding-left: @sidebar-margin;
   padding-right: @sidebar-margin;
 }
@@ -195,7 +195,7 @@
   background-image: none;
   background-color: @sidebar-text;
   -webkit-mask-repeat: no-repeat;
-  -webkit-mask-image: url(nylas://ui-darkside/images/down-arrow.svg);
+  -webkit-mask-image: url(../static/images/ui-darkside/down-arrow.svg);
 }
 
 .account-sidebar .item,
@@ -332,7 +332,7 @@
 
 // Make corresponding toolbar match threadlist background
 .column-ThreadList,
-.sheet-toolbar-container [data-column='1'] {
+.sheet-toolbar-container > div:nth-child(2) {
   height: 100%;
   background: @threadlist-bg;
   border-bottom: 1px solid @border-color;
@@ -513,9 +513,9 @@ body.is-blurred .list-tabular .list-tabular-item.keyboard-cursor {
 
 // Make toolbars match panels
 .column-MessageList,
-.sheet-toolbar-container [data-column='2'],
+.sheet-toolbar-container > div:nth-child(3),
 .column-MessageListSidebar,
-.sheet-toolbar-container [data-column='3']  {
+.sheet-toolbar-container > div:nth-child(4)  {
   height: 100%;
   background: @messagelist-bg;
   border-left: 1px solid @border-color;
@@ -625,7 +625,7 @@ body.is-blurred .list-tabular .list-tabular-item.keyboard-cursor {
 
 .list-tabular .list-tabular-item.selected .checkmark .inner {
   background-color: @accent;
-  background-image: url(nylas://ui-darkside/images/checkmark.svg);
+  background-image: url(../static/images/ui-darkside/checkmark.svg);
   background-size: 8px 6px;
 }
 
@@ -684,16 +684,16 @@ body.is-blurred .list-tabular .list-tabular-item.keyboard-cursor {
   border-right: none;
 }
 
-.sheet-toolbar-container.mode-popout,
+.sheet-toolbar-container.mode-popout {
 // mode-list toolbar
-[data-reactid=".1.0.1.$=1$1=02Thread=02toolbar"] [data-column='0'],
+// [data-reactid=".1.0.1.$=1$1=02Thread=02toolbar"] [data-column='0'],
 // Preferences toolbar
-[data-reactid=".1.0.1.$=1$1=02Preferences=02toolbar"] [data-column='0'] {
+// [data-reactid=".1.0.1.$=1$1=02Preferences=02toolbar"] [data-column='0'] {
   background-image: none;
   background-color: tint(@sidebar, 90%);
 }
 
-.sheet-toolbar-container.mode-popout [data-column='0'] {
+.sheet-toolbar-container.mode-popout > div:nth-child(1) {
   background: transparent;
 }