Fix layout issues in the agogo theme for smaller viewports (#11594)

Co-authored-by: Lukas Engelter <lukas.engelter@netgo.de>

CHANGES

@@ -88,6 +88,9 @@ Bugs fixed
   Patch by Bénédikt Tran.
 * #11591: Fix support for C coverage in ``sphinx.ext.coverage`` extension.
   Patch by Stephen Finucane.
+* #11594: HTML Theme: Enhancements to horizontal scrolling on smaller
+  devices in the ``agogo`` theme.
+  Patch by Lukas Engelter.
 
 Testing
 -------

sphinx/themes/agogo/static/agogo.css_t

@@ -19,6 +19,10 @@ body {
   line-height: 1.4em;
   color: black;
   background-color: {{ theme_bgcolor }};
+
+  /* fix for background colors breaking at horizontal
+    scrolling on smaller devices */
+  min-width: fit-content;
 }
 
 
@@ -131,8 +135,7 @@ dt:target, .highlighted {
 /* Header */
 
 div.header {
-  padding-top: 10px;
-  padding-bottom: 10px;
+  padding: 1em;
 }
 
 div.header .headertitle {
@@ -169,8 +172,7 @@ img.logo {
 /* Content */
 div.content-wrapper {
   background-color: white;
-  padding-top: 20px;
-  padding-bottom: 20px;
+  padding: 1em;
 }
 
 div.document {