Improve source tree and search results (firefox-devtools#2836)

* Change colors for tree and search results in dark theme

* Fix collapsing borders in search and search results

Author: diéssica gurskas

src/components/shared/ManagedTree.css

@@ -25,6 +25,10 @@
   background-color: var(--theme-selection-background);
 }
 
+.theme-dark .tree .node.focused {
+  background-color: var(--theme-selection-background-semitransparent);
+}
+
 html:not([dir="rtl"]) .tree .node > div {
   margin-left: 10px;
 }

src/components/shared/ResultList.css

@@ -1,11 +1,11 @@
-
 .result-list {
   list-style: none;
   width: 100%;
   background-color: var(--theme-toolbar-background);
   margin: 0px;
   padding: 0px;
   overflow: auto;
+  width: calc(100% - 1px); /* 1px fixes the hidden right border */
 }
 
 .result-list.big {
@@ -23,10 +23,7 @@
   padding: 4px 13px;
   display: flex;
   justify-content: space-between;
-}
-
-.result-list li:first-child {
-  border-top: none;
+  border: 1px solid transparent;
 }
 
 .result-list.big li {
@@ -41,19 +38,18 @@
 }
 
 .result-list li.selected {
-  border: 1px solid var(--theme-selection-background);
-}
-
-.result-list.big li.selected {
-  padding-left: 9px;
-  padding-top: 9px;
+  border-color: var(--theme-selection-background);
 }
 
 .search-bar .result-list li.selected {
   background-color: var(--theme-selection-background);
   color: white;
 }
 
+.theme-dark .search-bar .result-list li.selected {
+  background-color: var(--theme-body-background);
+}
+
 .result-list li .title {
   line-height: 1.5em;
   word-break: break-all;