Make top navbar fixed

app/assets/stylesheets/base.sass

@@ -5,6 +5,7 @@ body
   font-family: "Source Sans Pro", "Helvetica Neue", Helvetica, Arial, sans-serif
   font-size: 15px
   background-color: $background-color
+  padding-top: 42px
 
   .btn
     font-size: 15px

app/assets/stylesheets/header.sass

@@ -3,8 +3,9 @@ header.navbar
   color: #fff
   border-radius: 0
   border: 0
-  min-height: 40px
+  min-height: 42px
   margin-bottom: 0
+  border-bottom: 1px solid #222222
 
   .navbar-nav
     > li
@@ -62,10 +63,13 @@ header.navbar
             background-color: #444
 
   .navbar-collapse
-    border-color: #666 !important
+    border-color: #444 !important
 
   .navbar-toggle
-    border-color: #888
+    border: 0
+    padding: 10px
+    margin: 3px 5px 0 0
+    border-radius: 0
 
     .icon-bar
       background-color: #888
@@ -90,3 +94,7 @@ header.navbar
 
     .caret
       margin-left: 10px
+
+@media (max-width: 767px)
+  .navbar-default .navbar-nav .open .dropdown-menu > li > a
+    color: #fff

app/views/layouts/_header.html.slim

@@ -1,4 +1,4 @@
-header.navbar.navbar-default[role="navigation"]
+header.navbar.navbar-default.navbar-fixed-top[role="navigation"]
   .container
     .navbar-header
       button.navbar-toggle[type="button" data-toggle="collapse" data-target=".navbar-ex1-collapse"]