diff --git a/config/en/mkdocs.yaml b/config/en/mkdocs.yaml
index ab0378b..361adb3 100755
--- a/config/en/mkdocs.yaml
+++ b/config/en/mkdocs.yaml
@@ -1,14 +1,6 @@
 site_name: My notes
 docs_dir: '../../docs/en'
 
-extra_css:
-  - stylesheets/extra.css
-
-extra_javascript:
-  - javascripts/mathjax.js
-  - https://polyfill.io/v3/polyfill.min.js?features=es6
-  - https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js
-
 theme:
   name: material
   features:
@@ -49,6 +41,11 @@ markdown_extensions:
   - pymdownx.details
   - pymdownx.superfences
 
+extra_javascript:
+  - javascripts/mathjax.js
+  - https://polyfill.io/v3/polyfill.min.js?features=es6
+  - https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js
+
 nav:
   - 'Welcome': index.md
   - 'Mathematics':
diff --git a/docs/stylesheets/extra.css b/docs/stylesheets/extra.css
deleted file mode 100644
index 0c11edd..0000000
--- a/docs/stylesheets/extra.css
+++ /dev/null
@@ -1,31 +0,0 @@
-:root {
-
-    /* Primary color shades */
-    --md-primary-fg-color: #861f41;
-    --md-primary-fg-color--light: #861f4194;
-    --md-primary-fg-color--dark: #ac325a;
-    --md-primary-bg-color: hsla(0, 0%, 100%, 1);
-    --md-primary-bg-color--light: hsla(0, 0%, 100%, 0.7);
-    --md-text-link-color: hsla(231, 48%, 48%, 1);
-
-    /* Accent color shades */
-    --md-accent-fg-color: rgb(98, 18, 189);
-    --md-accent-fg-color--transparent: hsla(189, 100%, 37%, 0.1);
-    --md-accent-bg-color: hsla(0, 0%, 100%, 1);
-    --md-accent-bg-color--light: hsla(0, 0%, 100%, 0.7);
-    --md-default-fg-color--light: hsla(0, 100%, 50%, 0.7);
-  }
-  
-  :root > * {
-  
-    /* Code block color shades */
-    --md-code-bg-color: hsla(0, 0%, 96%, 1);
-    --md-code-fg-color: hsla(200, 18%, 26%, 1);
-
-    /* Footer */
-    --md-footer-bg-color: #861f41;
-    --md-footer-bg-color--dark: hsla(0, 0%, 0%, 0.32);
-    --md-footer-fg-color: hsla(0, 0%, 100%, 1);
-    --md-footer-fg-color--light: hsla(0, 0%, 100%, 0.7);
-    --md-footer-fg-color--lighter: hsla(0, 0%, 100%, 0.3);
-  }
\ No newline at end of file