Fix login form alignment in Chrome

It looks that margin-top with percent value does not work the same as in Firefox.

skins/elastic/styles/styles.less

@@ -145,10 +145,11 @@ a.disabled:not(.btn) {
 }
 
 #login-form {
-    margin: auto;
-    margin-top: 35%;
+    margin: 0 auto;
+    top: 35%;
     width: 95%;
     max-width: 280px;
+    position: relative;
 
     // Fixes input width and position in IE11
     .row {

skins/elastic/templates/login.html

@@ -5,15 +5,15 @@
 <div class="content selected no-navbar" role="main">
 	<roundcube:form id="login-form" name="login-form" method="post" class="propform">
 	<roundcube:object name="loginform" form="login-form" size="40" submit=true />
+		<div id="login-footer" role="contentinfo">
+			<roundcube:object name="productname" condition="config:display_product_info &gt; 0" />
+			<roundcube:object name="version" condition="config:display_product_info == 2" />
+			<roundcube:if condition="config:support_url" />
+				&nbsp;&#9899;&nbsp; <a href="<roundcube:var name='config:support_url' />" target="_blank" class="support-link"><roundcube:label name="support" /></a>
+			<roundcube:endif />
+			<roundcube:container name="loginfooter" id="login-footer" />
+		</div>
 	</form>
-	<div id="login-footer" role="contentinfo">
-		<roundcube:object name="productname" condition="config:display_product_info &gt; 0" />
-		<roundcube:object name="version" condition="config:display_product_info == 2" />
-		<roundcube:if condition="config:support_url" />
-			&nbsp;&#9899;&nbsp; <a href="<roundcube:var name='config:support_url' />" target="_blank" class="support-link"><roundcube:label name="support" /></a>
-		<roundcube:endif />
-		<roundcube:container name="loginfooter" id="login-footer" />
-	</div>
 </div>
 
 <noscript>