diff --git a/yarn.lock b/yarn.lock
index e8ae2db..8aa7630 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -408,11 +408,11 @@ chokidar@1.7.0:
     fsevents "^1.0.0"
 
 clean-css@^4.0.4:
-  version "4.1.6"
-  resolved "https://registry.yarnpkg.com/clean-css/-/clean-css-4.1.6.tgz#5a47beb526994cb4f7bf36188a55ed3b45528f0b"
-  integrity sha1-Wke+tSaZTLT3vzYYilXtO0VSjws=
+  version "4.2.3"
+  resolved "https://registry.yarnpkg.com/clean-css/-/clean-css-4.2.3.tgz#507b5de7d97b48ee53d84adb0160ff6216380f78"
+  integrity sha512-VcMWDN54ZN/DS+g58HYL5/n4Zrqe8vHJpGA8KdgUXFU4fuP/aHNw8eld9SyEIyabIMJX/0RaY/fplOo5hYLSFA==
   dependencies:
-    source-map "0.5.x"
+    source-map "~0.6.0"
 
 cliui@^2.1.0:
   version "2.1.0"
@@ -2868,11 +2868,16 @@ socket.io@1.6.0:
     socket.io-client "1.6.0"
     socket.io-parser "2.3.1"
 
-source-map@0.5.x, source-map@^0.5.1, source-map@^0.5.3, source-map@~0.5.1:
+source-map@^0.5.1, source-map@^0.5.3, source-map@~0.5.1:
   version "0.5.6"
   resolved "https://registry.yarnpkg.com/source-map/-/source-map-0.5.6.tgz#75ce38f52bf0733c5a7f0c118d81334a2bb5f412"
   integrity sha1-dc449SvwczxafwwRjYEzSiu19BI=
 
+source-map@~0.6.0:
+  version "0.6.1"
+  resolved "https://registry.yarnpkg.com/source-map/-/source-map-0.6.1.tgz#74722af32e9614e9c287a8d0bbde48b5e2f1a263"
+  integrity sha512-UjgapumWlbMhkBgzT7Ykc5YXUT46F0iKu8SGXq0bcwP5dz/h0Plj6enJqjz1Zbq2l5WaqYnrVbwWOWMyF3F47g==
+
 sparkles@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/sparkles/-/sparkles-1.0.0.tgz#1acbbfb592436d10bbe8f785b7cc6f82815012c3"