diff --git a/client/src/components/layout/misc/MaterialThemeProvider.tsx b/client/src/components/layout/misc/MaterialThemeProvider.tsx
index a4e70f02d..b47054c61 100644
--- a/client/src/components/layout/misc/MaterialThemeProvider.tsx
+++ b/client/src/components/layout/misc/MaterialThemeProvider.tsx
@@ -1,4 +1,5 @@
 import { createMuiTheme, ThemeProvider } from "@material-ui/core";
+import { ColourConfig } from "lib/config";
 import React from "react";
 import { JustChildren } from "types/react";
 
@@ -6,6 +7,14 @@ const theme = createMuiTheme({
 	typography: {
 		fontFamily: "Poppins",
 	},
+	palette: {
+		// for reasons unfathomable to mere mortals
+		// material UI uses "secondary" as the primary colour
+		// for things like tab indicators.
+		secondary: {
+			main: ColourConfig.primary,
+		},
+	},
 });
 
 export function MaterialThemeProvider({ children }: JustChildren) {