diff --git a/package.json b/package.json
index e39b3a2..76a500e 100644
--- a/package.json
+++ b/package.json
@@ -43,9 +43,9 @@
     "bugs": "https://github.com/TryGhost/Casper/issues",
     "contributors": "https://github.com/TryGhost/Casper/graphs/contributors",
     "devDependencies": {
-        "autoprefixer": "6.3.6",
+        "autoprefixer": "6.7.7",
         "beeper": "1.1.1",
-        "cssnano": "3.7.1",
+        "cssnano": "3.10.0",
         "gscan": "2.2.1",
         "gulp": "3.9.1",
         "gulp-filter": "5.1.0",
@@ -56,7 +56,7 @@
         "gulp-watch": "4.3.11",
         "gulp-zip": "4.2.0",
         "postcss-color-function": "2.0.1",
-        "postcss-custom-properties": "5.0.1",
+        "postcss-custom-properties": "5.0.2",
         "postcss-easy-import": "1.0.1",
         "pump": "3.0.0"
     },
diff --git a/yarn.lock b/yarn.lock
index b71be45..affeb2f 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -246,18 +246,7 @@ atob@^2.1.1:
   version "2.1.2"
   resolved "https://registry.yarnpkg.com/atob/-/atob-2.1.2.tgz#6d9517eb9e030d2436666651e86bd9f6f13533c9"
 
-autoprefixer@6.3.6:
-  version "6.3.6"
-  resolved "https://registry.yarnpkg.com/autoprefixer/-/autoprefixer-6.3.6.tgz#de772e1fcda08dce0e992cecf79252d5f008e367"
-  dependencies:
-    browserslist "~1.3.1"
-    caniuse-db "^1.0.30000444"
-    normalize-range "^0.1.2"
-    num2fraction "^1.2.2"
-    postcss "^5.0.19"
-    postcss-value-parser "^3.2.3"
-
-autoprefixer@^6.3.1:
+autoprefixer@6.7.7, autoprefixer@^6.3.1:
   version "6.7.7"
   resolved "https://registry.yarnpkg.com/autoprefixer/-/autoprefixer-6.7.7.tgz#1dbd1c835658e35ce3f9984099db00585c782014"
   dependencies:
@@ -439,7 +428,7 @@ babylon@^6.18.0:
   version "6.18.0"
   resolved "https://registry.yarnpkg.com/babylon/-/babylon-6.18.0.tgz#af2f3b88fa6f5c1e4c634d1a0f8eac4f55b395e3"
 
-balanced-match@0.1.0, balanced-match@~0.1.0:
+balanced-match@0.1.0:
   version "0.1.0"
   resolved "https://registry.yarnpkg.com/balanced-match/-/balanced-match-0.1.0.tgz#b504bd05869b39259dd0c5efc35d843176dccc4a"
 
@@ -579,12 +568,6 @@ browserslist@^1.3.6, browserslist@^1.5.2, browserslist@^1.7.6:
     caniuse-db "^1.0.30000639"
     electron-to-chromium "^1.2.7"
 
-browserslist@~1.3.1:
-  version "1.3.6"
-  resolved "https://registry.yarnpkg.com/browserslist/-/browserslist-1.3.6.tgz#952ff48d56463d3b538f85ef2f8eaddfd284b133"
-  dependencies:
-    caniuse-db "^1.0.30000525"
-
 bser@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/bser/-/bser-2.0.0.tgz#9ac78d3ed5d915804fd87acb158bc797147a1719"
@@ -673,7 +656,7 @@ caniuse-api@^1.5.2:
     lodash.memoize "^4.1.2"
     lodash.uniq "^4.5.0"
 
-caniuse-db@^1.0.30000444, caniuse-db@^1.0.30000525, caniuse-db@^1.0.30000529, caniuse-db@^1.0.30000634, caniuse-db@^1.0.30000639:
+caniuse-db@^1.0.30000529, caniuse-db@^1.0.30000634, caniuse-db@^1.0.30000639:
   version "1.0.30000824"
   resolved "https://registry.yarnpkg.com/caniuse-db/-/caniuse-db-1.0.30000824.tgz#bba3ff425296e04caa37fe426259206a7056551b"
 
@@ -999,14 +982,14 @@ css@2.X:
     source-map-resolve "^0.5.2"
     urix "^0.1.0"
 
-cssnano@3.7.1:
-  version "3.7.1"
-  resolved "https://registry.yarnpkg.com/cssnano/-/cssnano-3.7.1.tgz#ac25028a8646591215cc3da5e11ddc8e01764ea7"
+cssnano@3.10.0:
+  version "3.10.0"
+  resolved "https://registry.yarnpkg.com/cssnano/-/cssnano-3.10.0.tgz#4f38f6cea2b9b17fa01490f23f1dc68ea65c1c38"
   dependencies:
     autoprefixer "^6.3.1"
     decamelize "^1.1.2"
     defined "^1.0.0"
-    indexes-of "^1.0.1"
+    has "^1.0.1"
     object-assign "^4.0.1"
     postcss "^5.0.14"
     postcss-calc "^5.2.0"
@@ -3473,11 +3456,11 @@ postcss-convert-values@^2.3.4:
     postcss "^5.0.11"
     postcss-value-parser "^3.1.2"
 
-postcss-custom-properties@5.0.1:
-  version "5.0.1"
-  resolved "https://registry.yarnpkg.com/postcss-custom-properties/-/postcss-custom-properties-5.0.1.tgz#e07d4f6c78e547cf04274f120f490d236e33ea19"
+postcss-custom-properties@5.0.2:
+  version "5.0.2"
+  resolved "https://registry.yarnpkg.com/postcss-custom-properties/-/postcss-custom-properties-5.0.2.tgz#9719d78f2da9cf9f53810aebc23d4656130aceb1"
   dependencies:
-    balanced-match "~0.1.0"
+    balanced-match "^0.4.2"
     postcss "^5.0.0"
 
 postcss-discard-comments@^2.0.4:
@@ -3706,7 +3689,7 @@ postcss-zindex@^2.0.1:
     postcss "^5.0.4"
     uniqs "^2.0.0"
 
-postcss@^5.0.0, postcss@^5.0.10, postcss@^5.0.11, postcss@^5.0.12, postcss@^5.0.13, postcss@^5.0.14, postcss@^5.0.16, postcss@^5.0.19, postcss@^5.0.2, postcss@^5.0.4, postcss@^5.0.5, postcss@^5.0.8, postcss@^5.2.12, postcss@^5.2.16:
+postcss@^5.0.0, postcss@^5.0.10, postcss@^5.0.11, postcss@^5.0.12, postcss@^5.0.13, postcss@^5.0.14, postcss@^5.0.16, postcss@^5.0.2, postcss@^5.0.4, postcss@^5.0.5, postcss@^5.0.8, postcss@^5.2.12, postcss@^5.2.16:
   version "5.2.18"
   resolved "https://registry.yarnpkg.com/postcss/-/postcss-5.2.18.tgz#badfa1497d46244f6390f58b319830d9107853c5"
   dependencies: