Reduce font-size for headers for nicer and more compact look

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/assets/stylesheets/framework/typography.scss

@@ -37,7 +37,7 @@
   }
 
   h1 {
-    font-size: 2.25em;
+    font-size: 2em;
     font-weight: 600;
     margin: 1em 0 10px;
     padding: 0 0 0.3em;
@@ -46,7 +46,7 @@
   }
 
   h2 {
-    font-size: 1.8em;
+    font-size: 1.6em;
     font-weight: 600;
     margin: 1em 0 10px;
     padding-bottom: 0.3em;
@@ -56,7 +56,7 @@
 
   h3 {
     margin: 1em 0 10px;
-    font-size: 1.5em;
+    font-size: 1.4em;
   }
 
   h4 {