Add responsive layout

The main navigation will be collapsed until the viewport
minimum width reaches the Bootstrap defined 'lg' breakpoint
(defaults to 992px).

- Adding motion variables and updating some CSS values to
  use existing Sass variables

Signed-off-by: Yoshie Muranaka <yoshiemuranaka@gmail.com>
Change-Id: Id159b84da6adf55fdb15842b0e33b1ede4eeceb4
diff --git a/src/components/Global/PageContainer.vue b/src/components/Global/PageContainer.vue
index 8efbf7b..8396bd5 100644
--- a/src/components/Global/PageContainer.vue
+++ b/src/components/Global/PageContainer.vue
@@ -1,5 +1,5 @@
 <template>
-  <main id="main-content">
+  <main id="main-content" class="page-container">
     <slot />
   </main>
 </template>
@@ -12,12 +12,14 @@
 
 <style lang="scss" scoped>
 main {
+  width: 100%;
+  height: 100%;
   padding-top: $spacer * 1.5;
   padding-bottom: $spacer * 3;
-  padding-left: $spacer * 2;
+  padding-left: $spacer;
   padding-right: $spacer;
-  background-color: $gray-100;
-  height: 100%;
-  min-height: calc(100vh - 60px /*header height*/);
+  @include media-breakpoint-up($responsive-layout-bp) {
+    padding-left: $spacer * 2;
+  }
 }
 </style>