Examples updates (#24898)

* fix cover nav

* Improve signin visuals and alignment with that flexbox love

* rewrite cover example in flexbox

* lighten signin bg

* first pass at pricing example

* redo examples index with data file

* tighten up spacing a bit

* update navbar descriptions

* link pricing

* move that back

* property order

* Fix test errors.

* Compress pricing.png.

* add form validation example

* remove that

* rename that

* restyle and space out

* fix errors

* change order

* cleanup album css and styles

* tweak examples index

* make it a badge

* options

* improve sticky footer alignment

* redesign example index

* brand new blog layout

* start new screenshots

* new product example page a la apple

* add email field

* fix linter, remove unused blog css

* hook up feather icons to start

* redo dashboard

* fix linting

* add floating labels example

* formatting

* formatting

* lint

* fix values on select

* optional input, plus input group

* new dashboard image

* start to reboot the offcanvas example

* updated images

* new offcanvas mostly implemented

* linting

* edit description

* more description changes

* - Add vertical margin to album hero buttons for when they're stacked
- Adjust font-size and padding for pricing header and hero
- Fix checkout's stacked column margins, plus update their check/radio
markup
- Update product's utilities to be responsive
- Made blog cards somewhat responsive (needs a bit more work tbh)

* drop leading zero

* more linting

* swap empty images for holder, fix border

* dist the docs

* navbars have no margin-bottom to begin

* add css var, tweak padding for mobile

* comment headers

* nix commented out code

* nix the navbar structure for a custom one, stack it on mobile

* tweak heading button group for mobile

* Removed narrow jumbotron and justified nav examples as these are easily accomplished with new components in v4

* improve card sizing on pricing

* update and compress

docs/4.0/examples/dashboard/dashboard.css

@@ -1,20 +1,11 @@
-/*
- * Base structure
- */
-
-/* Move down content because we have a fixed navbar that is 3.5rem tall */
 body {
-  padding-top: 3.5rem;
+  font-size: .875rem;
 }
 
-/*
- * Typography
- */
-
-h1 {
-  padding-bottom: 9px;
-  margin-bottom: 20px;
-  border-bottom: 1px solid #eee;
+.feather {
+  width: 16px;
+  height: 16px;
+  vertical-align: text-bottom;
 }
 
 /*
@@ -23,42 +14,80 @@ h1 {
 
 .sidebar {
   position: fixed;
-  top: 51px;
+  top: 0;
   bottom: 0;
   left: 0;
-  z-index: 1000;
-  padding: 20px 0;
+  z-index: 100; /* Behind the navbar */
+  padding: 0;
+  box-shadow: inset -1px 0 0 rgba(0, 0, 0, .1);
+}
+
+.sidebar-sticky {
+  position: -webkit-sticky;
+  position: sticky;
+  top: 48px; /* Height of navbar */
+  height: calc(100vh - 48px);
+  padding-top: .5rem;
   overflow-x: hidden;
   overflow-y: auto; /* Scrollable contents if viewport is shorter than content. */
-  border-right: 1px solid #eee;
-}
-
-.sidebar .nav {
-  margin-bottom: 20px;
-}
-
-.sidebar .nav-item {
-  width: 100%;
-}
-
-.sidebar .nav-item + .nav-item {
-  margin-left: 0;
 }
 
 .sidebar .nav-link {
-  border-radius: 0;
+  font-weight: 500;
+  color: #333;
+}
+
+.sidebar .nav-link .feather {
+  margin-right: 4px;
+  color: #999;
+}
+
+.sidebar .nav-link.active {
+  color: #007bff;
+}
+
+.sidebar .nav-link:hover .feather,
+.sidebar .nav-link.active .feather {
+  color: inherit;
+}
+
+.sidebar-heading {
+  font-size: .75rem;
+  text-transform: uppercase;
 }
 
 /*
- * Dashboard
+ * Navbar
  */
 
-/* Placeholders */
-.placeholders {
-  padding-bottom: 3rem;
+.navbar-brand {
+  padding-top: .75rem;
+  padding-bottom: .75rem;
+  font-size: 1rem;
+  background-color: rgba(0, 0, 0, .25);
+  box-shadow: inset -1px 0 0 rgba(0, 0, 0, .25);
 }
 
-.placeholder img {
-  padding-top: 1.5rem;
-  padding-bottom: 1.5rem;
+.navbar .form-control {
+  padding: .75rem 1rem;
+  border-width: 0;
+  border-radius: 0;
 }
+
+.form-control-dark {
+  color: #fff;
+  background-color: rgba(255, 255, 255, .1);
+  border-color: rgba(255, 255, 255, .1);
+}
+
+.form-control-dark:focus {
+  border-color: transparent;
+  box-shadow: 0 0 0 3px rgba(255, 255, 255, .25);
+}
+
+/*
+ * Utilities
+ */
+
+.border-top { border-top: 1px solid #e5e5e5; }
+.border-bottom { border-bottom: 1px solid #e5e5e5; }