diff --git a/src/material/theme.css b/src/material/theme.css
index 1228ffd..f1ed6ed 100644
--- a/src/material/theme.css
+++ b/src/material/theme.css
@@ -82,25 +82,27 @@
   --tutu-color-error-on-surface: #d32f2f;
   --tutu-color-inactive-on-surface: #757575;
 
-  --tutu-shadow-e1: 0px 1px 2px 0px #9e9e9e;
+  --tutu-color-shadow: rgba(0, 0, 0, 0.15);
+
+  --tutu-shadow-e1: 0px 1px 2px 0px var(--tutu-color-shadow);
   /* Switch */
-  --tutu-shadow-e2: 0px 2px 4px 0px #9e9e9e;
+  --tutu-shadow-e2: 0px 2px 4px 0px var(--tutu-color-shadow);
   /* (Resting) cards, raised button, quick entry / search bar */
-  --tutu-shadow-e3: 0px 3px 6px 0px #9e9e9e;
+  --tutu-shadow-e3: 0px 3px 6px 0px var(--tutu-color-shadow);
   /* Refresh indicator, quick entry / search bar (scrolled) */
-  --tutu-shadow-e4: 0px 4px 8px 0px #9e9e9e;
+  --tutu-shadow-e4: 0px 4px 8px 0px var(--tutu-color-shadow);
   /* App bar */
-  --tutu-shadow-e6: 0px 6px 12px 0px #9e9e9e;
+  --tutu-shadow-e6: 0px 6px 12px 0px var(--tutu-color-shadow);
   /* Snack bar, FAB (resting) */
-  --tutu-shadow-e8: 0px 8px 16px 0px #9e9e9e;
+  --tutu-shadow-e8: 0px 8px 16px 0px var(--tutu-color-shadow);
   /* Menu, (picked-up) cards, (pressed) raise button */
-  --tutu-shadow-e9: 0px 9px 18px 0px #9e9e9e;
+  --tutu-shadow-e9: 0px 9px 18px 0px var(--tutu-color-shadow);
   /* Submenu (+1dp for each submenu) */
-  --tutu-shadow-e12: 0px 12px 24px 0px #9e9e9e;
+  --tutu-shadow-e12: 0px 12px 24px 0px var(--tutu-color-shadow);
   /* (pressed) FAB */
-  --tutu-shadow-e16: 0px 16px 32px 0px #9e9e9e;
+  --tutu-shadow-e16: 0px 16px 32px 0px var(--tutu-color-shadow);
   /* Nav drawer, right drawer, modal bottom sheet */
-  --tutu-shadow-e24: 0px 24px 48px 0px #9e9e9e;
+  --tutu-shadow-e24: 0px 24px 48px 0px var(--tutu-color-shadow);
   /* Dialog, picker */
 
   --tutu-anim-curve-std: cubic-bezier(0.4, 0, 0.2, 1);