diff --git a/inst/lib/bsw4/dist/cyborg/_bootswatch.scss b/inst/lib/bsw4/dist/cyborg/_bootswatch.scss
index 63f304e..6dad3f6 100644
--- a/inst/lib/bsw4/dist/cyborg/_bootswatch.scss
+++ b/inst/lib/bsw4/dist/cyborg/_bootswatch.scss
@@ -7,20 +7,29 @@
 $web-font-path: "https://fonts.googleapis.com/css2?family=Roboto:wght@400;700&display=swap" !default;
 @import url($web-font-path);

+// Functions ===================================================================
+
+@function darken($color, $percent) {
+  @return mix($body-bg, $color, $percent);
+}
+@function lighten($color, $percent) {
+  @return mix($body-color, $color, $percent);
+}
+
 // Navbar ======================================================================

 .navbar {
   &.bg-primary {
-    border: 1px solid $gray-700;
+    border: 1px solid body-mix(50%);
   }

   &.bg-dark {
     background-color: $body-bg !important;
-    border: 1px solid $gray-700;
+    border: 1px solid body-mix(50%);
   }

   &.bg-light {
-    background-color: $gray-500 !important;
+    background-color: body-mix(16%) !important;
   }

   &.fixed-top {
@@ -38,7 +47,7 @@ $web-font-path: "https://fonts.googleapis.com/css2?family=Roboto:wght@400;700&di
   @each $color, $value in $theme-colors {
     &-#{$color} {
       @if $enable-gradients {
-        background: $value linear-gradient(180deg, mix($white, $value, 15%), $value) repeat-x;
+        background: $value linear-gradient(180deg, mix($contrast-bg, $value, 15%), $value) repeat-x;
       } @else {
         background-color: $value;
       }
@@ -49,7 +58,7 @@ $web-font-path: "https://fonts.googleapis.com/css2?family=Roboto:wght@400;700&di
 // Tables ======================================================================

 table {
-  color: $white;
+  color: $contrast-bg;
 }

 .table {
@@ -204,7 +213,7 @@ table {
 // Forms =======================================================================

 legend {
-  color: $white;
+  color: $contrast-bg;
 }

 .form-control {
@@ -221,10 +230,10 @@ legend {
 .nav-tabs,
 .nav-pills {
   .nav-link {
-    color: $white;
+    color: $contrast-bg;

     &:hover {
-      background-color: $gray-700;
+      background-color: body-mix(50%);
     }

     &.disabled,
@@ -241,7 +250,7 @@ legend {

 .breadcrumb {
   a {
-    color: $white;
+    color: $contrast-bg;
   }
 }

@@ -255,18 +264,18 @@ legend {

 .alert {
   border: none;
-  color: $white;
+  color: $contrast-bg;

   a,
   .alert-link {
-    color: $white;
+    color: $contrast-bg;
     text-decoration: underline;
   }

   @each $color, $value in $theme-colors {
     &-#{$color} {
       @if $enable-gradients {
-        background: $value linear-gradient(180deg, mix($white, $value, 15%), $value) repeat-x;
+        background: $value linear-gradient(180deg, mix($contrast-bg, $value, 15%), $value) repeat-x;
       } @else {
         background-color: $value;
       }
@@ -276,7 +285,7 @@ legend {

 .badge {
   &-warning {
-    color: $white;
+    color: $contrast-bg;
   }
 }

@@ -292,20 +301,20 @@ legend {

 .list-group-item {
   &:hover {
-    background-color: $gray-700;
-    color: $white;
+    background-color: body-mix(50%);
+    color: $contrast-bg;
   }

   &-action {
-    color: $gray-500;
+    color: body-mix(16%);

     .list-group-item-heading {
-      color: $gray-500;
+      color: body-mix(16%);
     }
   }

   &:hover .list-group-item-heading {
-    color: $white;
+    color: $contrast-bg;
   }
 }

diff --git a/inst/lib/bsw4/dist/cyborg/_variables.scss b/inst/lib/bsw4/dist/cyborg/_variables.scss
index 85c7483..6a30ace 100755
--- a/inst/lib/bsw4/dist/cyborg/_variables.scss
+++ b/inst/lib/bsw4/dist/cyborg/_variables.scss
@@ -28,22 +26,26 @@ $green:   #77b300 !default;
 $teal:    #20c997 !default;
 $cyan:    #93c !default;

+// Body
+
+@function body-mix($weight) {
+    @return mix(#060606, $gray-400, $weight);
+}
+$body-bg:                   body-mix(100%) !default;
+$body-color:                body-mix(0%) !default;
+
+// Most defaults to cascade from body bg/color, but some
+// colors really want to a full contrast from the bg color
+$contrast-bg: color-contrast($body-bg) !default;
+
 $primary:       $blue !default;
-$secondary:     $gray-600 !default;
+$secondary:     body-mix(67%) !default;
 $success:       $green !default;
 $info:          $cyan !default;
 $warning:       $yellow !default;
 $danger:        $red !default;
-$light:         $gray-800 !default;
-$dark:          $gray-400 !default;
-
-$yiq-contrasted-threshold:  175 !default;
-
-
-// Body
-
-$body-bg:       #060606 !default;
-$body-color:    $gray-400 !default;
+$light:         body-mix(33%) !default;
+$dark:          $body-color !default;

 // Fonts

@@ -55,16 +61,16 @@ $h2-font-size:            3rem !default;
 $h3-font-size:            2.5rem !default;
 $h4-font-size:            2rem !default;
 $h5-font-size:            1.5rem !default;
-$headings-color:          $white !default;
+$headings-color:          $contrast-bg !default;

 // Tables

-$table-color:                   $white !default;
-$table-accent-bg:               rgba($white, .05) !default;
-$table-hover-bg:                rgba($white, .075) !default;
-$table-border-color:            $gray-700 !default;
-$table-dark-bg:                 $gray-500 !default;
-$table-dark-border-color:       darken($gray-500, 7.5%) !default;
+$table-color:                   $contrast-bg !default;
+$table-accent-bg:               rgba($contrast-bg, .05) !default;
+$table-hover-bg:                rgba($contrast-bg, .075) !default;
+$table-border-color:            body-mix(50%) !default;
+$table-dark-bg:                 body-mix(16%) !default;
+$table-dark-border-color:       body-mix(23%) !default;

 // Buttons

@@ -72,40 +78,40 @@ $input-btn-padding-x:       1rem !default;

 // Forms

-$input-disabled-bg:                 $gray-400 !default;
-$input-border-color:                $white !default;
-$input-group-addon-color:           $white !default;
-$input-group-addon-bg:              $gray-700 !default;
+$input-disabled-bg:                 $body-color !default;
+$input-border-color:                $contrast-bg !default;
+$input-group-addon-color:           $contrast-bg !default;
+$input-group-addon-bg:              body-mix(50%) !default;
 $input-group-addon-border-color:    transparent !default;
-$custom-file-color:                 $white !default;
-$custom-file-border-color:          $gray-700 !default;
+$custom-file-color:                 $contrast-bg !default;
+$custom-file-border-color:          body-mix(50%) !default;

 // Dropdowns

-$dropdown-bg:                    $gray-700 !default;
-$dropdown-divider-bg:            $gray-800 !default;
-$dropdown-link-color:            $white !default;
-$dropdown-link-hover-color:      $white !default;
+$dropdown-bg:                    body-mix(50%) !default;
+$dropdown-divider-bg:            body-mix(67%) !default;
+$dropdown-link-color:            $contrast-bg !default;
+$dropdown-link-hover-color:      $contrast-bg !default;
 $dropdown-link-hover-bg:         $primary !default;

 // Navs

 $nav-tabs-border-color:                       $table-border-color !default;
 $nav-tabs-link-hover-border-color:            $nav-tabs-border-color !default;
-$nav-tabs-link-active-color:                  $white !default;
+$nav-tabs-link-active-color:                  $contrast-bg !default;
 $nav-tabs-link-active-bg:                     $nav-tabs-border-color !default;
 $nav-tabs-link-active-border-color:           $nav-tabs-border-color !default;

 // Navbar

-$navbar-dark-hover-color:           $white !default;
+$navbar-dark-hover-color:           $contrast-bg !default;

 // Pagination

-$pagination-color:                     $white !default;
-$pagination-bg:                        $gray-700 !default;
+$pagination-color:                     $contrast-bg !default;
+$pagination-bg:                        body-mix(50%) !default;
 $pagination-border-color:              transparent !default;
-$pagination-hover-color:               $white !default;
+$pagination-hover-color:               $contrast-bg !default;
 $pagination-hover-bg:                  $primary !default;
 $pagination-hover-border-color:        $pagination-border-color !default;
 $pagination-disabled-bg:               $pagination-bg !default;
@@ -114,54 +120,54 @@ $pagination-disabled-border-color:     $pagination-border-color !default;

 // Jumbotron

-$jumbotron-bg:                      $gray-700 !default;
+$jumbotron-bg:                      body-mix(50%) !default;

 // Cards

-$card-bg:                           $gray-700 !default;
+$card-bg:                           body-mix(50%) !default;

 // Tooltips

-$tooltip-bg:                        $gray-700 !default;
+$tooltip-bg:                        body-mix(50%) !default;
 $tooltip-opacity:                   1 !default;

 // Popovers

-$popover-bg:                        $gray-700 !default;
+$popover-bg:                        body-mix(50%) !default;

 // Toasts

-$toast-color:                       $white !default;
-$toast-background-color:            $gray-800 !default;
-$toast-border-color:                $gray-700 !default;
+$toast-color:                       $contrast-bg !default;
+$toast-background-color:            body-mix(67%) !default;
+$toast-border-color:                body-mix(50%) !default;
 $toast-header-color:                $body-color !default;
 $toast-header-background-color:     $toast-background-color !default;
 $toast-header-border-color:         $toast-border-color !default;

 // Modals

-$modal-content-bg:                  $gray-800 !default;
-$modal-header-border-color:         $gray-700 !default;
+$modal-content-bg:                  body-mix(67%) !default;
+$modal-header-border-color:         body-mix(50%) !default;

 // Progress bars

-$progress-bg:                       $gray-700 !default;
+$progress-bg:                       body-mix(50%) !default;

 // List group

-$list-group-bg:                     $gray-800 !default;
-$list-group-border-color:           $gray-700 !default;
+$list-group-bg:                     body-mix(67%) !default;
+$list-group-border-color:           body-mix(50%) !default;
 $list-group-hover-bg:               $primary !default;
-$list-group-disabled-bg:            $gray-700 !default;
+$list-group-disabled-bg:            body-mix(50%) !default;
 $list-group-action-active-bg:       $primary !default;

 // Breadcrumbs

-$breadcrumb-bg:                     $gray-700 !default;
+$breadcrumb-bg:                     body-mix(50%) !default;

 // Close

-$close-color:                       $white !default;
+$close-color:                       $contrast-bg !default;
 $close-text-shadow:                 none !default;

 // Code