[static-web] wiki: Update style for <hr> tag

[Tom Tryfonidis <tomtryf src gnome org>]

commit 5139ac3ab2ca588adb89f3069bdba220744060b2
Author: Tom Tryfonidis <tomtryf gnome org>
Date:   Tue May 16 18:49:49 2017 +0300

    wiki: Update style for <hr> tag

 wiki.gnome.org/gnome-responsive/css/layout.css |    7 +++----
 1 files changed, 3 insertions(+), 4 deletions(-)
---
diff --git a/wiki.gnome.org/gnome-responsive/css/layout.css b/wiki.gnome.org/gnome-responsive/css/layout.css
index 3a43f0a..d867455 100644
--- a/wiki.gnome.org/gnome-responsive/css/layout.css
+++ b/wiki.gnome.org/gnome-responsive/css/layout.css
@@ -211,12 +211,11 @@ div.in-column {
 }
 
 hr {
-    color: #888;
-    background: #888;
+    background-color: #c0c0c0;
     border: 0;
     height: 1px;
-    width: 90%;
-    text-align: center;
+    width: 40%;
+    margin: 30px auto;
     clear: both;
 }