diff --git a/src/_includes/base.liquid b/src/_includes/base.liquid
index 891ed1d7..3cd22024 100644
--- a/src/_includes/base.liquid
+++ b/src/_includes/base.liquid
@@ -89,18 +89,19 @@
     <script>
       (() => {
         const currentTheme = sessionStorage?.getItem('theme');
-        if (!currentTheme) sessionStorage?.setItem('theme', (window.matchMedia('(prefers-color-scheme: dark)').matches ? 'dark' : 'light'))
+        const prefersDarkScheme = window.matchMedia('(prefers-color-scheme: dark)').matches;
+        if (!currentTheme) sessionStorage?.setItem('theme', (prefersDarkScheme ? 'dark' : 'light'))
         if (currentTheme === 'dark') {
           document.body.classList.add('theme__dark')
         } else if (currentTheme === 'light') {
           document.body.classList.add('theme__light')
-        } else if (this.prefersDarkScheme) {
+        } else if (prefersDarkScheme) {
           document.body.classList.add('theme__dark')
-        } else if (!this.prefersDarkScheme) {
+        } else if (!prefersDarkScheme) {
           document.body.classList.add('theme__light')
         }
       })();
     </script>
     {{ content }}
   </body>
-</html>
\ No newline at end of file
+</html>