diff --git a/website/package.json b/website/package.json
index bec233b..1ff6474 100644
--- a/website/package.json
+++ b/website/package.json
@@ -187,7 +187,7 @@
     "css-select-base-adapter": "^0.1.0",
     "css-tree": "^1.0.0-alpha25",
     "css-url-regex": "^1.1.0",
-    "css-what": "^2.1.0",
+    "css-what": "^2.1.3",
     "cssnano": "^3.10.0",
     "csso": "^3.5.1",
     "currently-unhandled": "^0.4.1",
diff --git a/website/yarn.lock b/website/yarn.lock
index 1aea9ee..cceb4ca 100644
--- a/website/yarn.lock
+++ b/website/yarn.lock
@@ -1597,10 +1597,10 @@ css-url-regex@^1.1.0:
   resolved "https://registry.yarnpkg.com/css-url-regex/-/css-url-regex-1.1.0.tgz#83834230cc9f74c457de59eebd1543feeb83b7ec"
   integrity sha1-g4NCMMyfdMRX3lnuvRVD/uuDt+w=
 
-css-what@2.1, css-what@^2.1.0:
-  version "2.1.0"
-  resolved "https://registry.yarnpkg.com/css-what/-/css-what-2.1.0.tgz#9467d032c38cfaefb9f2d79501253062f87fa1bd"
-  integrity sha1-lGfQMsOM+u+58teVASUwYvh/ob0=
+css-what@2.1, css-what@^2.1.3:
+  version "2.1.3"
+  resolved "https://registry.yarnpkg.com/css-what/-/css-what-2.1.3.tgz#a6d7604573365fe74686c3f311c56513d88285f2"
+  integrity sha512-a+EPoD+uZiNfh+5fxw2nO9QwFa6nJe2Or35fGY6Ipw1R3R4AGz1d1TEZrCegvw2YTmZ0jXirGYlzxxpYSHwpEg==
 
 css@2.X:
   version "2.2.3"
@@ -4352,7 +4352,7 @@ once@^1.3.0, once@^1.4.0:
 
 onetime@^1.0.0, onetime@^1.1.0:
   version "1.1.0"
-  resolved "http://registry.npmjs.org/onetime/-/onetime-1.1.0.tgz#a1f7838f8314c516f05ecefcbc4ccfe04b4ed789"
+  resolved "https://registry.npmjs.org/onetime/-/onetime-1.1.0.tgz#a1f7838f8314c516f05ecefcbc4ccfe04b4ed789"
   integrity sha1-ofeDj4MUxRbwXs78vEzP4EtO14k=
 
 onetime@^2.0.0: