diff --git a/docs/source/conf.py b/docs/source/conf.py
index aeb81cd146..fafe8db5c8 100644
--- a/docs/source/conf.py
+++ b/docs/source/conf.py
@@ -115,7 +115,7 @@
 # Output file base name for HTML help builder.
 htmlhelp_basename = 'BraveBrowserdoc'
 
-html_css_files = '_static/custom.css'
+html_css_files = ['_static/custom.css']
 
 
 # -- Options for LaTeX output ------------------------------------------------
@@ -169,4 +169,4 @@
 ]
 
 def setup(app):
-    app.add_stylesheet('custom.css')
\ No newline at end of file
+    app.add_stylesheet('custom.css')