fix(docs-infra): fix CSS issues on home page and search results (#35098)

On home page, image size set to 400px, which make the page not render
properly on devices below the size of 400px width.

Also, when search results were scrolled, they interfered with the top
nav items. Added border at the top of the search results container so
that the results are not visible under the nav items during scrolling.

PR Close #35098

aio/src/styles/1-layouts/_marketing-layout.scss

@@ -97,7 +97,6 @@ section#intro {
 
   .hero-logo {
     display: flex;
-    width: 400px;
 
     @media (max-width: 780px) {
       justify-content: center;

aio/src/styles/2-modules/_search-results.scss

@@ -6,7 +6,8 @@ aio-search-results {
     flex-direction: row;
     justify-content: space-around;
     overflow: auto;
-    padding: 68px 32px 0;
+    padding: 0px 32px;
+    border-top: 68px solid transparent;
     width: auto;
     max-height: 95vh;
     position: fixed;