Rework progress demos (fixes #660)

docs/_pages/components.md

@@ -186,6 +186,7 @@ categories:
             - caption: Default
               file: progress-default.html
               demo_file: progress-default-demo.html
+          - snippet_group:
             - caption: Indeterminate
               file: progress-indeterminate.html
               demo_file: progress-indeterminate-demo.html

src/progress/snippets/progress-buffering-demo.html

@@ -1,6 +1,7 @@
 <style>
   .progress-demo {
-    width: 100px;
+    width: 50vw;
+    max-width: 260px;
   }
 </style>
 

src/progress/snippets/progress-default-demo.html

@@ -1,6 +1,7 @@
 <style>
   .progress-demo {
-    width: 100px;
+    width: 50vw;
+    max-width: 260px;
   }
 </style>
 

src/progress/snippets/progress-indeterminate-demo.html

@@ -1,6 +1,8 @@
 <style>
   .progress-demo {
-    width: 100px;
+    width: 50vw;
+    max-width: 260px;
+    margin: 60px 0;
   }
 </style>