Better layout for when nav is long and scrolls

_sass/layout.scss

@@ -17,13 +17,15 @@
 
 .side-bar {
   z-index: 100;
+  display: flex;
+  flex-wrap: wrap;
   padding-top: $gutter-spacing-sm;
   padding-bottom: $gutter-spacing-sm;
   background-color: $grey-lt-000;
 
   @include mq(md) {
+    flex-wrap: nowrap;
     position: absolute;
-    display: flex;
     width: $nav-width + 16px;
     height: 100%;
     padding-top: $gutter-spacing * 2;
@@ -107,11 +109,9 @@
 
 .navigation {
   @include mq(md) {
-    position: absolute;
-    top: 0;
-    right: 0;
-    height: 100%;
     padding-top: $sp-8;
+    overflow-y: auto;
+    flex: 1 1 auto;
   }
 }
 
@@ -127,9 +127,14 @@ body {
 
 .site-footer {
   position: absolute;
-  bottom: $sp-3;
+  bottom: 0;
+  padding-top: $sp-4;
+  padding-bottom: $sp-4;
 
   @include mq(md) {
-    right: 0;
+    position: static;
+    align-self: flex-end;
+    justify-self: end;
+    background-color: $grey-lt-000;
   }
 }

_sass/navigation.scss

@@ -4,9 +4,7 @@
 
 .site-title {
   display: block;
-  flex-grow: 1;
-  flex-shrink: 1;
-  flex-basis: auto;
+  flex: 1 1 auto;
   background-color: $grey-lt-000;
 
   @include mq(md) {
@@ -27,7 +25,7 @@
   list-style: none;
 
   @include mq(md) {
-    margin-top: $sp-10;
+    margin-top: 0;
   }
 }
 
@@ -91,15 +89,6 @@
   }
 }
 
-.side-bar {
-  display: flex;
-  flex-wrap: wrap;
-
-  @include mq(md) {
-    display: block;
-    overflow-y: auto;
-  }
-}
 
 .navigation-list-toggle {
   position: absolute;