diff --git a/package.json b/package.json
index 0377254a..adf2ae22 100644
--- a/package.json
+++ b/package.json
@@ -48,8 +48,8 @@
     "impunity": "^1.0.9",
     "mdn-polyfills": "^5.20.0",
     "node-html-parser": "^4.0.0",
-    "postcss-css-variables": "^0.17.0",
-    "postcss-flexbugs-fixes": "^4.2.1",
+    "postcss-css-variables": "^0.18.0",
+    "postcss-flexbugs-fixes": "^5.0.2",
     "regenerator-runtime": "^0.13.7",
     "rollup": "^2.26.4",
     "rollup-plugin-cleanup": "^3.1.1",
diff --git a/yarn.lock b/yarn.lock
index 16d32144..10a18ec8 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1472,7 +1472,7 @@ caniuse-lite@^1.0.30001272, caniuse-lite@^1.0.30001280:
   resolved "https://registry.yarnpkg.com/caniuse-lite/-/caniuse-lite-1.0.30001283.tgz#8573685bdae4d733ef18f78d44ba0ca5fe9e896b"
   integrity sha512-9RoKo841j1GQFSJz/nCXOj0sD7tHBtlowjYlrqIUS812x9/emfBLBt6IyMz1zIaYc/eRL8Cs6HPUVi2Hzq4sIg==
 
-chalk@^2.0.0, chalk@^2.4.1, chalk@^2.4.2:
+chalk@^2.0.0:
   version "2.4.2"
   resolved "https://registry.yarnpkg.com/chalk/-/chalk-2.4.2.tgz#cd42541677a54333cf541a49108c1432b44c9424"
   integrity sha512-Mti+f9lpJNcwF4tWV8/OrTTtF1gZi+f8FqlyAdouralcFWFQWF2+NgCHShjkCb+IFBLq9buZwE1xckQU4peSuQ==
@@ -2816,46 +2816,25 @@ picomatch@^2.2.2, picomatch@^2.2.3:
   resolved "https://registry.yarnpkg.com/picomatch/-/picomatch-2.3.0.tgz#f1f061de8f6a4bf022892e2d128234fb98302972"
   integrity sha512-lY1Q/PiJGC2zOv/z391WOTD+Z02bCgsFfvxoXXf6h7kv9o+WmsmzYqrAwY63sNgOxE4xEdq0WyUnXfKeBrSvYw==
 
-postcss-css-variables@^0.17.0:
-  version "0.17.0"
-  resolved "https://registry.yarnpkg.com/postcss-css-variables/-/postcss-css-variables-0.17.0.tgz#56cba1d9f0360609136cfbfda8bbd2c1ed2e4082"
-  integrity sha512-/ZpFnJgksNOrQA72b3DKhExYh+0e2P5nEc3aPZ62G7JLmdDjWRFv3k/q4LxV7uzXFnmvkhXRbdVIiH5tKgfFNA==
+postcss-css-variables@^0.18.0:
+  version "0.18.0"
+  resolved "https://registry.yarnpkg.com/postcss-css-variables/-/postcss-css-variables-0.18.0.tgz#d97b6da19e86245eb817006e11117382f997bb93"
+  integrity sha512-lYS802gHbzn1GI+lXvy9MYIYDuGnl1WB4FTKoqMQqJ3Mab09A7a/1wZvGTkCEZJTM8mSbIyb1mJYn8f0aPye0Q==
   dependencies:
     balanced-match "^1.0.0"
     escape-string-regexp "^1.0.3"
     extend "^3.0.1"
-    postcss "^6.0.8"
 
-postcss-flexbugs-fixes@^4.2.1:
-  version "4.2.1"
-  resolved "https://registry.yarnpkg.com/postcss-flexbugs-fixes/-/postcss-flexbugs-fixes-4.2.1.tgz#9218a65249f30897deab1033aced8578562a6690"
-  integrity sha512-9SiofaZ9CWpQWxOwRh1b/r85KD5y7GgvsNt1056k6OYLvWUun0czCvogfJgylC22uJTwW1KzY3Gz65NZRlvoiQ==
-  dependencies:
-    postcss "^7.0.26"
+postcss-flexbugs-fixes@^5.0.2:
+  version "5.0.2"
+  resolved "https://registry.yarnpkg.com/postcss-flexbugs-fixes/-/postcss-flexbugs-fixes-5.0.2.tgz#2028e145313074fc9abe276cb7ca14e5401eb49d"
+  integrity sha512-18f9voByak7bTktR2QgDveglpn9DTbBWPUzSOe9g0N4WR/2eSt6Vrcbf0hmspvMI6YWGywz6B9f7jzpFNJJgnQ==
 
 postcss-value-parser@^4.1.0:
   version "4.1.0"
   resolved "https://registry.yarnpkg.com/postcss-value-parser/-/postcss-value-parser-4.1.0.tgz#443f6a20ced6481a2bda4fa8532a6e55d789a2cb"
   integrity sha512-97DXOFbQJhk71ne5/Mt6cOu6yxsSfM0QGQyl0L25Gca4yGWEGJaig7l7gbCX623VqTBNGLRLaVUCnNkcedlRSQ==
 
-postcss@^6.0.8:
-  version "6.0.23"
-  resolved "https://registry.yarnpkg.com/postcss/-/postcss-6.0.23.tgz#61c82cc328ac60e677645f979054eb98bc0e3324"
-  integrity sha512-soOk1h6J3VMTZtVeVpv15/Hpdl2cBLX3CAw4TAbkpTJiNPk9YP/zWcD1ND+xEtvyuuvKzbxliTOIyvkSeSJ6ag==
-  dependencies:
-    chalk "^2.4.1"
-    source-map "^0.6.1"
-    supports-color "^5.4.0"
-
-postcss@^7.0.26:
-  version "7.0.32"
-  resolved "https://registry.yarnpkg.com/postcss/-/postcss-7.0.32.tgz#4310d6ee347053da3433db2be492883d62cec59d"
-  integrity sha512-03eXong5NLnNCD05xscnGKGDZ98CyzoqPSMjOe6SuoQY7Z2hIj0Ld1g/O/UQRuOle2aRtiIRDg9tDcTGAkLfKw==
-  dependencies:
-    chalk "^2.4.2"
-    source-map "^0.6.1"
-    supports-color "^6.1.0"
-
 postcss@^8.3.8:
   version "8.3.9"
   resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.3.9.tgz#98754caa06c4ee9eb59cc48bd073bb6bd3437c31"
@@ -3157,11 +3136,6 @@ source-map@^0.5.0:
   resolved "https://registry.yarnpkg.com/source-map/-/source-map-0.5.7.tgz#8a039d2d1021d22d1ea14c80d8ea468ba2ef3fcc"
   integrity sha1-igOdLRAh0i0eoUyA2OpGi6LvP8w=
 
-source-map@^0.6.1:
-  version "0.6.1"
-  resolved "https://registry.yarnpkg.com/source-map/-/source-map-0.6.1.tgz#74722af32e9614e9c287a8d0bbde48b5e2f1a263"
-  integrity sha512-UjgapumWlbMhkBgzT7Ykc5YXUT46F0iKu8SGXq0bcwP5dz/h0Plj6enJqjz1Zbq2l5WaqYnrVbwWOWMyF3F47g==
-
 sourcemap-codec@^1.4.4:
   version "1.4.8"
   resolved "https://registry.yarnpkg.com/sourcemap-codec/-/sourcemap-codec-1.4.8.tgz#ea804bd94857402e6992d05a38ef1ae35a9ab4c4"
@@ -3205,20 +3179,13 @@ strip-json-comments@^3.1.0, strip-json-comments@^3.1.1:
   resolved "https://registry.yarnpkg.com/strip-json-comments/-/strip-json-comments-3.1.1.tgz#31f1281b3832630434831c310c01cccda8cbe006"
   integrity sha512-6fPc+R4ihwqP6N/aIv2f1gMH8lOVtWQHoqC4yK6oSDVVocumAsfCqjkXnqiYMhmMwS/mEHLp7Vehlt3ql6lEig==
 
-supports-color@^5.3.0, supports-color@^5.4.0:
+supports-color@^5.3.0:
   version "5.5.0"
   resolved "https://registry.yarnpkg.com/supports-color/-/supports-color-5.5.0.tgz#e2e69a44ac8772f78a1ec0b35b689df6530efc8f"
   integrity sha512-QjVjwdXIt408MIiAqCX4oUKsgU2EqAGzs2Ppkm4aQYbjm+ZEWEcW4SfFNTr4uMNZma0ey4f5lgLrkB0aX0QMow==
   dependencies:
     has-flag "^3.0.0"
 
-supports-color@^6.1.0:
-  version "6.1.0"
-  resolved "https://registry.yarnpkg.com/supports-color/-/supports-color-6.1.0.tgz#0764abc69c63d5ac842dd4867e8d025e880df8f3"
-  integrity sha512-qe1jfm1Mg7Nq/NSh6XE24gPXROEVsWHxC1LIx//XNlD9iw7YZQGjZNjYN7xGaEG6iKdA8EtNFW6R0gjnVXp+wQ==
-  dependencies:
-    has-flag "^3.0.0"
-
 supports-color@^7.1.0:
   version "7.2.0"
   resolved "https://registry.yarnpkg.com/supports-color/-/supports-color-7.2.0.tgz#1b7dcdcb32b8138801b3e478ba6a51caa89648da"