diff --git a/src/features/increaseContrast/ui/styles.css b/src/features/increaseContrast/ui/styles.css
new file mode 100644
index 0000000..026230e
--- /dev/null
+++ b/src/features/increaseContrast/ui/styles.css
@@ -0,0 +1,3 @@
+.thread-summary.read:not(.checked) {
+  background: var(--TWPT-thread-read-background, #ecedee) !important;
+}