diff --git a/docs/labwc-theme.5.scd b/docs/labwc-theme.5.scd
index efc3a1a5..fad8a77e 100644
--- a/docs/labwc-theme.5.scd
+++ b/docs/labwc-theme.5.scd
@@ -358,10 +358,12 @@ all are supported.
 	Border width of selected window switcher items in pixels. Default is 2.
 
 *osd.window-switcher.style-thumbnail.item.active.border.color*
-	Color of border around selected window switcher items. Default is #589bda.
+	Color of border around selected window switcher items.
+	Default is *osd.label.text.color* with 50% opacity.
 
 *osd.window-switcher.style-thumbnail.item.active.bg.color*
-	Color of selected window switcher items. Default is #c7e2fc.
+	Color of selected window switcher items.
+	Default is *osd.label.text.color* with 15% opacity.
 
 *osd.window-switcher.style-thumbnail.item.icon.size*
 	Size of window icons in window switcher items in pixels. Default is 60.
diff --git a/docs/themerc b/docs/themerc
index 7b251a3c..a52dfacd 100644
--- a/docs/themerc
+++ b/docs/themerc
@@ -106,8 +106,8 @@ osd.window-switcher.style-thumbnail.item.width: 300
 osd.window-switcher.style-thumbnail.item.height: 250
 osd.window-switcher.style-thumbnail.item.padding: 10
 osd.window-switcher.style-thumbnail.item.active.border.width: 2
-osd.window-switcher.style-thumbnail.item.active.border.color: #589bda
-osd.window-switcher.style-thumbnail.item.active.bg.color: #c7e2fc
+osd.window-switcher.style-thumbnail.item.active.border.color: #706f6d
+osd.window-switcher.style-thumbnail.item.active.bg.color: #bfbcba
 osd.window-switcher.style-thumbnail.item.icon.size: 60
 
 osd.window-switcher.preview.border.width: 1
diff --git a/src/theme.c b/src/theme.c
index d5279367..a3aec34a 100644
--- a/src/theme.c
+++ b/src/theme.c
@@ -613,8 +613,8 @@ theme_builtin(struct theme *theme, struct server *server)
 	theme->osd_window_switcher_thumbnail.item_height = 250;
 	theme->osd_window_switcher_thumbnail.item_padding = 10;
 	theme->osd_window_switcher_thumbnail.item_active_border_width = 2;
-	parse_color("#589bda", theme->osd_window_switcher_thumbnail.item_active_border_color);
-	parse_color("#c7e2fc", theme->osd_window_switcher_thumbnail.item_active_bg_color);
+	theme->osd_window_switcher_thumbnail.item_active_border_color[0] = FLT_MIN;
+	theme->osd_window_switcher_thumbnail.item_active_bg_color[0] = FLT_MIN;
 	theme->osd_window_switcher_thumbnail.item_icon_size = 60;
 
 	/* inherit settings in post_processing() if not set elsewhere */
@@ -1633,6 +1633,31 @@ get_titlebar_height(struct theme *theme)
 	return h;
 }
 
+/* Blend foreground color (with new alpha) with background color */
+static void
+blend_color_with_bg(float *dst, float *fg, float fg_a, float *bg)
+{
+	/* Guard against zero division */
+	if (fg[3] <= 0.0f) {
+		memset(dst, 0, sizeof(float) * 4);
+		return;
+	}
+
+	/* Redo premultiplication to update foreground alpha */
+	float new_fg[4] = {
+		fg[0] / fg[3] * fg_a,
+		fg[1] / fg[3] * fg_a,
+		fg[2] / fg[3] * fg_a,
+		fg_a,
+	};
+
+	/* Blend colors */
+	dst[0] = new_fg[0] + bg[0] * (1.0f - new_fg[3]);
+	dst[1] = new_fg[1] + bg[1] * (1.0f - new_fg[3]);
+	dst[2] = new_fg[2] + bg[2] * (1.0f - new_fg[3]);
+	dst[3] = new_fg[3] + bg[3] * (1.0f - new_fg[3]);
+}
+
 static void
 post_processing(struct theme *theme)
 {
@@ -1721,6 +1746,14 @@ post_processing(struct theme *theme)
 		memcpy(theme->osd_border_color, theme->osd_label_text_color,
 			sizeof(theme->osd_border_color));
 	}
+	if (switcher_thumb_theme->item_active_border_color[0] == FLT_MIN) {
+		blend_color_with_bg(switcher_thumb_theme->item_active_border_color,
+			theme->osd_label_text_color, 0.50, theme->osd_bg_color);
+	}
+	if (switcher_thumb_theme->item_active_bg_color[0] == FLT_MIN) {
+		blend_color_with_bg(switcher_thumb_theme->item_active_bg_color,
+			theme->osd_label_text_color, 0.15, theme->osd_bg_color);
+	}
 	if (theme->osd_workspace_switcher_boxes_width == 0) {
 		theme->osd_workspace_switcher_boxes_height = 0;
 	}