diff --git a/R/sysdata.rda b/R/sysdata.rda
index b94643c70..339ec291f 100644
Binary files a/R/sysdata.rda and b/R/sysdata.rda differ
diff --git a/inst/lib/bs4/scss/_variables.scss b/inst/lib/bs4/scss/_variables.scss
index 02a58f248..143903f4b 100644
--- a/inst/lib/bs4/scss/_variables.scss
+++ b/inst/lib/bs4/scss/_variables.scss
@@ -69,7 +69,7 @@ $colors: map-merge(
 // Semantically, $secondary is closest to BS3's 'default' theme color;
 // so use that if specified. Otherwise, use a light instead of dark gray
 // default color for $default since that's closer to bootstrap 3's default
-$default: if(variable-exists("secondary"), $secondary, $gray-300) !default;
+$default: if(variable-exists("secondary") and type-of($secondary) == color, $secondary, $gray-300) !default;
 
 $primary:       $blue !default;
 $secondary:     $gray-600 !default;
diff --git a/inst/lib/bs5/scss/_variables.scss b/inst/lib/bs5/scss/_variables.scss
index 5ef7b3b6f..5645c14d2 100644
--- a/inst/lib/bs5/scss/_variables.scss
+++ b/inst/lib/bs5/scss/_variables.scss
@@ -300,7 +300,7 @@ $cyans: (
 // Semantically, $secondary is closest to BS3's 'default' theme color;
 // so use that if specified. Otherwise, use a light instead of dark gray
 // default color for $default since that's closer to bootstrap 3's default
-$default: if(variable-exists("secondary"), $secondary, $gray-300) !default;
+$default: if(variable-exists("secondary") and type-of($secondary) == color, $secondary, $gray-300) !default;
 
 // scss-docs-start theme-color-variables
 $primary:       $blue !default;
diff --git a/tools/patches/025-default-theme-color.patch b/tools/patches/025-default-theme-color.patch
index 70c7fc43a..13c4daf05 100644
--- a/tools/patches/025-default-theme-color.patch
+++ b/tools/patches/025-default-theme-color.patch
@@ -9,7 +9,7 @@ index 42d8142..dde6f2f 100644
 +// Semantically, $secondary is closest to BS3's 'default' theme color; 
 +// so use that if specified. Otherwise, use a light instead of dark gray
 +// default color for $default since that's closer to bootstrap 3's default
-+$default: if(variable-exists("secondary"), $secondary, $gray-300) !default;
++$default: if(variable-exists("secondary") and type-of($secondary) == color, $secondary, $gray-300) !default;
 +
  $primary:       $blue !default;
  $secondary:     $gray-600 !default;
@@ -35,7 +35,7 @@ index 706ee935..2ce8afc1 100644
 +// Semantically, $secondary is closest to BS3's 'default' theme color;
 +// so use that if specified. Otherwise, use a light instead of dark gray
 +// default color for $default since that's closer to bootstrap 3's default
-+$default: if(variable-exists("secondary"), $secondary, $gray-300) !default;
++$default: if(variable-exists("secondary") and type-of($secondary) == color, $secondary, $gray-300) !default;
 +
  // scss-docs-start theme-color-variables
  $primary:       $blue !default;