[epiphany] Minor: add comments explaining thumbnail height media queries

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 5bfabdada5bd18f57406ba8a639ea7e2d811e832
Author: Tobias Bernard <tbernard gnome org>
Date:   Sun Aug 4 23:10:40 2019 +0200

    Minor: add comments explaining thumbnail height media queries

 src/resources/about.css | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
---
diff --git a/src/resources/about.css b/src/resources/about.css
index 09a949a8f..29d46af7f 100644
--- a/src/resources/about.css
+++ b/src/resources/about.css
@@ -262,7 +262,7 @@ html.epiphany-html {
     text-decoration: none;
 }
 
-/* Hide 9th item on narrow widths to avoid uneven number*/
+/* Hide 9th item on narrow widths to avoid uneven number */
 .overview-item:last-child {
     display: none;
 }
@@ -295,12 +295,14 @@ html.epiphany-html {
     border-radius: 5px;
 }
 
+/* In order to preserve a wide aspect ratio as the layout changes, we need to reduce the height */
 @media (min-width: 341px) {
     .overview-thumbnail {
         height: 120px;
     }
 }
 
+/* After this point we can go back to the regular height */
 @media (min-width: 450px) {
     .overview-thumbnail {
         height: 160px;