Assorted style fixes/tweaks

scss/components/_layout.scss

@@ -27,6 +27,7 @@ body {
     margin: $gap;
     max-width: $site-max-width;
     overflow-x: hidden;
+    flex-grow: 1;
 
     @include media($medium-screen) {
       margin: $gap * 2;

scss/core/_util.scss

@@ -13,6 +13,10 @@
   width: 1px;
 }
 
+.hide {
+  @include hide;
+}
+
 @mixin unhide {
   border: unset;
   clip: unset;

scss/elements/_action_group.scss

@@ -4,8 +4,13 @@
   align-items: center;
   margin-top: $gap * 4;
 
-  .action-group__action {
+  .usa-button,
+  a {
     margin: 0 0 0 ($gap * 2);
+
+    @include media($medium-screen) {
+      margin: 0 0 0 ($gap * 4);
+    }
   }
 
   &:last-child {

scss/elements/_inputs.scss

@@ -60,7 +60,7 @@
 .usa-input {
   margin:  ($gap * 4) ($gap * 2) ($gap * 4) 0;
 
-  @includ media($medium-screen) {
+  @include media($medium-screen) {
     margin: ($gap * 4) 0;
   }
 
@@ -215,7 +215,19 @@ select {
 
     .form-col {
       .usa-input {
-        margin: 0 ($gap * 4) 0 0;
+        margin: 0 ($gap * 4);
+      }
+
+      &:first-child {
+        .usa-input {
+          margin-left: 0;
+        }
+      }
+
+      &:last-child {
+        .usa-input {
+          margin-right: 0;
+        }
       }
     }
   }

scss/elements/_panels.scss

@@ -45,7 +45,11 @@
   }
 
   .panel__heading {
-    margin: ($gap * 2) 0;
+    margin: $gap * 2;
+
+    @include media($medium-screen) {
+      margin: $gap * 4;
+    }
 
     h1, h2, h3, h4, h5, h6 {
       margin: 0;

scss/elements/_typography.scss

@@ -24,6 +24,13 @@ h1, h2, h3, h4, h5, h6 {
 
 }
 
+.h1 { @include h1; }
+.h2 { @include h2; }
+.h3 { @include h3; }
+.h4 { @include h4; }
+.h5 { @include h5; }
+.h6 { @include h6; }
+
 a,
 a:hover {
   transition:
@@ -37,9 +44,18 @@ a:visited {
   color: $color-blue;
 }
 
-dt {
+dl {
+  dt {
     display: inline;
     font-weight: bold;
+  }
+  dd {
+    -webkit-margin-start: 0;
+  }
+
+  > div {
+    margin-bottom: $gap * 2;
+  }
 }
 
 .subtitle {