docs: Add more design polish (#43802)

Fixing the theme toggle popover, search results design, and
sidebar/table of contents responsiveness.

Release Notes:

- N/A

docs/theme/css/chrome.css

@@ -365,16 +365,9 @@ mark.fade-out {
   color: var(--searchresults-header-fg);
 }
 
-.searchresults-outer {
-  margin-inline-start: auto;
-  margin-inline-end: auto;
-  max-width: var(--content-max-width);
-  border-block-end: 1px dashed var(--searchresults-border-color);
-}
-
 ul#searchresults {
   list-style: none;
-  padding-inline-start: 20px;
+  padding-inline-start: 0;
 }
 ul#searchresults li {
   margin: 10px 0px;
@@ -386,16 +379,16 @@ ul#searchresults li.focus {
 }
 ul#searchresults span.teaser {
   display: block;
-  clear: both;
-  margin-block-start: 5px;
-  margin-block-end: 0;
-  margin-inline-start: 20px;
-  margin-inline-end: 0;
   font-size: 0.8em;
+  margin-block-start: 5px;
+  margin-inline-start: 4px;
+  padding-inline-start: 2ch;
+  border-left: 1px solid var(--divider);
 }
 ul#searchresults span.teaser em {
   font-weight: bold;
-  font-style: normal;
+  color: var(--full-contrast);
+  background: var(--code-bg);
 }
 
 /* Sidebar */
@@ -475,7 +468,7 @@ ul#searchresults span.teaser em {
   background: var(--scrollbar);
 }
 
-@media only screen and (max-width: 619px) {
+@media only screen and (max-width: 780px) {
   .sidebar {
     position: fixed;
     top: 0;
@@ -494,16 +487,11 @@ ul#searchresults span.teaser em {
   }
 
   body.sidebar-open .sidebar {
+    box-shadow: var(--sidebar-mobile-shadow);
     transform: translateX(0);
   }
 }
 
-@media only screen and (min-width: 620px) {
-  .sidebar {
-    position: relative;
-  }
-}
-
 .chapter {
   list-style: none outside none;
   padding: 8px 20px 20px 20px;
@@ -631,7 +619,6 @@ ul#searchresults span.teaser em {
   padding: 0;
   list-style: none;
   display: none;
-  /* Don't let the children's background extend past the rounded corners. */
   overflow: hidden;
 }
 
@@ -769,6 +756,10 @@ ul#searchresults span.teaser em {
   width: 100%;
 }
 
+#searchbar {
+  margin: 0;
+}
+
 @media only screen and (max-width: 780px) {
   .header-bar {
     padding: 16px;
@@ -814,10 +805,6 @@ ul#searchresults span.teaser em {
     display: flex;
   }
 
-  .sidebar {
-    box-shadow: var(--sidebar-mobile-shadow);
-  }
-
   .theme-popup {
     right: 15px;
   }

docs/theme/css/general.css

@@ -68,6 +68,7 @@ h3,
 h4,
 h5,
 h6 {
+  position: relative;
   font-family: var(--title-font);
   font-weight: 480;
   color: var(--title-color);
@@ -152,10 +153,9 @@ h3:target::before,
 h4:target::before,
 h5:target::before,
 h6:target::before {
-  display: inline-block;
   content: "»";
-  margin-inline-start: -30px;
-  width: 30px;
+  position: absolute;
+  left: -1.5ch;
 }
 
 hr {

docs/theme/css/variables.css

@@ -86,7 +86,6 @@
   --searchbar-fg: #000;
   --searchbar-shadow-color: #aaa;
   --searchresults-header-fg: #666;
-  --searchresults-border-color: #888;
   --searchresults-li-bg: #e4f2fe;
   --search-mark-bg: #a2cff5;
 
@@ -183,7 +182,6 @@
   --searchbar-fg: hsl(220, 14%, 71%);
   --searchbar-shadow-color: hsl(220, 13%, 15%);
   --searchresults-header-fg: hsl(220, 14%, 60%);
-  --searchresults-border-color: hsl(220, 13%, 30%);
   --searchresults-li-bg: hsl(220, 13%, 25%);
   --search-mark-bg: hsl(220, 93%, 60%);