Merge branch '3.0.0-wip' of github.com:twitter/bootstrap into 3.0.0-wip

assets/css/docs.css

@@ -743,7 +743,6 @@ input.focused {
     right:  15px;
     bottom: 15px;
   }
-
   .bs-header {
     font-size: 21px;
     text-align: left;
@@ -799,12 +798,22 @@ input.focused {
 @media screen and (min-width: 992px) {
 
   /* Widen the fixed sidebar */
-  .bs-sidebar.affix {
-    position: fixed; /* Undo the static from mobile-first approach */
-    top: 50px;
+  .bs-sidebar.affix,
+  .bs-sidebar.affix-bottom {
     width: 213px;
   }
-
+  .bs-sidebar.affix {
+    position: fixed; /* Undo the static from mobile-first approach */
+    top: 80px;
+  }
+  .bs-sidebar.affix-bottom {
+    position: absolute; /* Undo the static from mobile-first approach */
+  }
+  .bs-sidebar.affix-bottom .bs-sidenav,
+  .bs-sidebar.affix .bs-sidenav {
+    margin-top: 0;
+    margin-bottom: 0;
+  }
   .bs-header h1,
   .bs-header p {
     margin-right: 380px;
@@ -824,6 +833,7 @@ input.focused {
 @media screen and (min-width: 1200px) {
 
   /* Widen the fixed sidebar again */
+  .bs-sidebar.affix-bottom,
   .bs-sidebar.affix {
     width: 270px;
   }

assets/js/application.js

@@ -13,12 +13,23 @@
       e.preventDefault()
     })
 
+
     // back to top
     setTimeout(function () {
-      $('.bs-sidebar').affix({
+      var $sideBar = $('.bs-sidebar')
+
+      $sideBar.affix({
         offset: {
-          top: function () { return $window.width() <= 980 ? 290 : 210 }
-        , bottom: 270
+          top: function () {
+            var offsetTop      = $sideBar.offset().top
+            var sideBarMargin  = parseInt($sideBar.children(0).css('margin-top'), 10)
+            var navOuterHeight = $('.bs-docs-nav').height()
+
+            return (this.top = offsetTop - navOuterHeight - sideBarMargin)
+          }
+        , bottom: function () {
+            return (this.bottom = $('.bs-footer').outerHeight(true))
+          }
         }
       })
     }, 100)