diff --git a/back-cover.typ b/back-cover.typ
index 255b38b..a55b545 100644
--- a/back-cover.typ
+++ b/back-cover.typ
@@ -1,4 +1,5 @@
-#import "color.typ": text_color_set
+#import "color.typ": text_color_set, theme_color_set
+#import "@preview/cetz:0.4.0"
 
 #{
 
@@ -6,5 +7,10 @@ set align(right)
 v(1fr)
 set text(22pt, fill: text_color_set.at("100"))
 box($ F_n = 1/(sqrt(5))[((1+sqrt(5))/2)^n-((1-sqrt(5))/2)^n] $)
+layout(ly => cetz.canvas(length: ly.width, {
+	import cetz.draw: *
+	line((0, 0), (1, 0), stroke: 3pt + theme_color_set.at("100"))
+	line((0, 0), (.25, 0), stroke: 3pt + text_color_set.at("100"))
+}))
 
 }
\ No newline at end of file