diff --git a/src/pages/_app.tsx b/src/pages/_app.tsx
index 1a93799..b2a0d4f 100644
--- a/src/pages/_app.tsx
+++ b/src/pages/_app.tsx
@@ -22,8 +22,8 @@ const GlobalCommonStyles = createGlobalStyle`
 html {
   font-family: ${fontFamily};
 
-  /* 12px */
-  font-size: ${fontSize * 0.75}pt;
+  /* 10px */
+  font-size: ${fontSize * (2 / 3)}pt;
   line-height: ${lineHeight};
 
   @media screen and (min-width: ${breakpoints.medium}) {