diff --git a/package-lock.json b/package-lock.json
index 5c7736d..572147c 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -11,7 +11,7 @@
       "dependencies": {
         "caniuse-api": "^3.0.0",
         "parse-css-font": "^2.0.2",
-        "postcss": "^5.0.16",
+        "postcss": "^8.4.31",
         "quote": "^0.4.0"
       },
       "devDependencies": {
@@ -96,6 +96,7 @@
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       "integrity": "sha1-w7M6te42DYbg5ijwRorn7yfWVN8=",
+      "dev": true,
       "engines": {
         "node": ">=0.10.0"
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@@ -104,6 +105,7 @@
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       "resolved": "https://registry.npmjs.org/ansi-styles/-/ansi-styles-2.2.1.tgz",
       "integrity": "sha1-tDLdM1i2NM914eRmQ2gkBTPB3b4=",
+      "dev": true,
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@@ -1454,6 +1456,7 @@
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       "resolved": "http://registry.npmjs.org/chalk/-/chalk-1.1.3.tgz",
       "integrity": "sha1-qBFcVeSnAv5NFQq9OHKCKn4J/Jg=",
+      "dev": true,
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@@ -1469,6 +1472,7 @@
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       "integrity": "sha1-U10EXOa2Nj+kARcIRimZXp3zJMc=",
+      "dev": true,
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@@ -2091,6 +2095,7 @@
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       "integrity": "sha1-G2HAViGQqN/2rjuyzwIAyhMLhtQ=",
+      "dev": true,
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       }
@@ -3479,6 +3484,7 @@
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       "integrity": "sha1-NPUEnOHs3ysGSa8+8k5F7TVBbZE=",
+      "dev": true,
       "dependencies": {
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@@ -3495,14 +3501,6 @@
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-      "resolved": "https://registry.npmjs.org/has-flag/-/has-flag-1.0.0.tgz",
-      "integrity": "sha1-nZ55MWXOAXoA8AQYxD+UKnsdEfo=",
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@@ -4221,11 +4219,6 @@
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-    "node_modules/js-base64": {
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-      "resolved": "https://registry.npmjs.org/js-base64/-/js-base64-2.4.9.tgz",
-      "integrity": "sha512-xcinL3AuDJk7VSzsHgb9DvvIXayBbadtMZ4HFPx8rUszbW1MuNMlwYVC4zzCZ6e1sqZpnNS5ZFYOhXqA39T7LQ=="
-    },
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       "resolved": "https://registry.npmjs.org/js-tokens/-/js-tokens-3.0.2.tgz",
@@ -4634,6 +4627,23 @@
       "dev": true,
       "optional": true
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+    "node_modules/nanoid": {
+      "version": "3.3.7",
+      "resolved": "https://registry.npmjs.org/nanoid/-/nanoid-3.3.7.tgz",
+      "integrity": "sha512-eSRppjcPIatRIMC1U6UngP8XFcz8MQWGQdt1MTBQ7NaAmvXDfvNxbvWV3x2y6CdEUciCSsDHDQZbhYaB8QEo2g==",
+      "funding": [
+        {
+          "type": "github",
+          "url": "https://github.com/sponsors/ai"
+        }
+      ],
+      "bin": {
+        "nanoid": "bin/nanoid.cjs"
+      },
+      "engines": {
+        "node": "^10 || ^12 || ^13.7 || ^14 || >=15.0.1"
+      }
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       "version": "1.2.13",
       "resolved": "https://registry.npmjs.org/nanomatch/-/nanomatch-1.2.13.tgz",
@@ -5054,6 +5064,11 @@
         "node": ">=0.10.0"
       }
     },
+    "node_modules/picocolors": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/picocolors/-/picocolors-1.0.0.tgz",
+      "integrity": "sha512-1fygroTLlHu66zi26VoTDv8yRgm0Fccecssto+MhsZ0D/DGW2sm8E8AjW7NU5VVTRt5GxbeZ5qBuJr+HyLYkjQ=="
+    },
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       "resolved": "http://registry.npmjs.org/pify/-/pify-2.3.0.tgz",
@@ -5143,17 +5158,30 @@
       }
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     "node_modules/postcss": {
-      "version": "5.2.18",
-      "resolved": "https://registry.npmjs.org/postcss/-/postcss-5.2.18.tgz",
-      "integrity": "sha512-zrUjRRe1bpXKsX1qAJNJjqZViErVuyEkMTRrwu4ud4sbTtIBRmtaYDrHmcGgmrbsW3MHfmtIf+vJumgQn+PrXg==",
+      "version": "8.4.31",
+      "resolved": "https://registry.npmjs.org/postcss/-/postcss-8.4.31.tgz",
+      "integrity": "sha512-PS08Iboia9mts/2ygV3eLpY5ghnUcfLV/EXTOW1E2qYxJKGGBUtNjN76FYHnMs36RmARn41bC0AZmn+rR0OVpQ==",
+      "funding": [
+        {
+          "type": "opencollective",
+          "url": "https://opencollective.com/postcss/"
+        },
+        {
+          "type": "tidelift",
+          "url": "https://tidelift.com/funding/github/npm/postcss"
+        },
+        {
+          "type": "github",
+          "url": "https://github.com/sponsors/ai"
+        }
+      ],
       "dependencies": {
-        "chalk": "^1.1.3",
-        "js-base64": "^2.1.9",
-        "source-map": "^0.5.6",
-        "supports-color": "^3.2.3"
+        "nanoid": "^3.3.6",
+        "picocolors": "^1.0.0",
+        "source-map-js": "^1.0.2"
       },
       "engines": {
-        "node": ">=0.12"
+        "node": "^10 || ^12 || >=14"
       }
     },
     "node_modules/power-assert-context-formatter": {
@@ -6461,6 +6489,15 @@
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       "integrity": "sha1-igOdLRAh0i0eoUyA2OpGi6LvP8w=",
+      "dev": true,
+      "engines": {
+        "node": ">=0.10.0"
+      }
+    },
+    "node_modules/source-map-js": {
+      "version": "1.2.0",
+      "resolved": "https://registry.npmjs.org/source-map-js/-/source-map-js-1.2.0.tgz",
+      "integrity": "sha512-itJW8lvSA0TXEphiRoawsCksnlf8SyvmFzIhltqAHluXd88pkCd+cXJVHTDwdCr0IzwptSm035IHQktUu1QUMg==",
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       }
@@ -6622,6 +6659,7 @@
       "version": "3.0.1",
       "resolved": "https://registry.npmjs.org/strip-ansi/-/strip-ansi-3.0.1.tgz",
       "integrity": "sha1-ajhfuIU9lS1f8F0Oiq+UJ43GPc8=",
+      "dev": true,
       "dependencies": {
         "ansi-regex": "^2.0.0"
       },
@@ -6665,17 +6703,6 @@
         "node": ">=0.10.0"
       }
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-    "node_modules/supports-color": {
-      "version": "3.2.3",
-      "resolved": "https://registry.npmjs.org/supports-color/-/supports-color-3.2.3.tgz",
-      "integrity": "sha1-ZawFBLOVQXHYpklGsq48u4pfVPY=",
-      "dependencies": {
-        "has-flag": "^1.0.0"
-      },
-      "engines": {
-        "node": ">=0.8.0"
-      }
-    },
     "node_modules/symbol": {
       "version": "0.2.3",
       "resolved": "https://registry.npmjs.org/symbol/-/symbol-0.2.3.tgz",
@@ -7405,12 +7432,14 @@
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       "version": "2.1.1",
       "resolved": "https://registry.npmjs.org/ansi-regex/-/ansi-regex-2.1.1.tgz",
-      "integrity": "sha1-w7M6te42DYbg5ijwRorn7yfWVN8="
+      "integrity": "sha1-w7M6te42DYbg5ijwRorn7yfWVN8=",
+      "dev": true
     },
     "ansi-styles": {
       "version": "2.2.1",
       "resolved": "https://registry.npmjs.org/ansi-styles/-/ansi-styles-2.2.1.tgz",
-      "integrity": "sha1-tDLdM1i2NM914eRmQ2gkBTPB3b4="
+      "integrity": "sha1-tDLdM1i2NM914eRmQ2gkBTPB3b4=",
+      "dev": true
     },
     "anymatch": {
       "version": "1.3.2",
@@ -8639,6 +8668,7 @@
       "version": "1.1.3",
       "resolved": "http://registry.npmjs.org/chalk/-/chalk-1.1.3.tgz",
       "integrity": "sha1-qBFcVeSnAv5NFQq9OHKCKn4J/Jg=",
+      "dev": true,
       "requires": {
         "ansi-styles": "^2.2.1",
         "escape-string-regexp": "^1.0.2",
@@ -8650,7 +8680,8 @@
         "supports-color": {
           "version": "2.0.0",
           "resolved": "https://registry.npmjs.org/supports-color/-/supports-color-2.0.0.tgz",
-          "integrity": "sha1-U10EXOa2Nj+kARcIRimZXp3zJMc="
+          "integrity": "sha1-U10EXOa2Nj+kARcIRimZXp3zJMc=",
+          "dev": true
         }
       }
     },
@@ -9177,7 +9208,8 @@
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       "version": "1.0.5",
       "resolved": "https://registry.npmjs.org/escape-string-regexp/-/escape-string-regexp-1.0.5.tgz",
-      "integrity": "sha1-G2HAViGQqN/2rjuyzwIAyhMLhtQ="
+      "integrity": "sha1-G2HAViGQqN/2rjuyzwIAyhMLhtQ=",
+      "dev": true
     },
     "eslint": {
       "version": "4.18.2",
@@ -10338,6 +10370,7 @@
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/has-ansi/-/has-ansi-2.0.0.tgz",
       "integrity": "sha1-NPUEnOHs3ysGSa8+8k5F7TVBbZE=",
+      "dev": true,
       "requires": {
         "ansi-regex": "^2.0.0"
       }
@@ -10348,11 +10381,6 @@
       "integrity": "sha1-ZxRKUmDDT8PMpnfQQdr1L+e3iy8=",
       "dev": true
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-    "has-flag": {
-      "version": "1.0.0",
-      "resolved": "https://registry.npmjs.org/has-flag/-/has-flag-1.0.0.tgz",
-      "integrity": "sha1-nZ55MWXOAXoA8AQYxD+UKnsdEfo="
-    },
     "has-value": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/has-value/-/has-value-1.0.0.tgz",
@@ -10923,11 +10951,6 @@
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-    "js-base64": {
-      "version": "2.4.9",
-      "resolved": "https://registry.npmjs.org/js-base64/-/js-base64-2.4.9.tgz",
-      "integrity": "sha512-xcinL3AuDJk7VSzsHgb9DvvIXayBbadtMZ4HFPx8rUszbW1MuNMlwYVC4zzCZ6e1sqZpnNS5ZFYOhXqA39T7LQ=="
-    },
     "js-tokens": {
       "version": "3.0.2",
       "resolved": "https://registry.npmjs.org/js-tokens/-/js-tokens-3.0.2.tgz",
@@ -11260,6 +11283,11 @@
       "dev": true,
       "optional": true
     },
+    "nanoid": {
+      "version": "3.3.7",
+      "resolved": "https://registry.npmjs.org/nanoid/-/nanoid-3.3.7.tgz",
+      "integrity": "sha512-eSRppjcPIatRIMC1U6UngP8XFcz8MQWGQdt1MTBQ7NaAmvXDfvNxbvWV3x2y6CdEUciCSsDHDQZbhYaB8QEo2g=="
+    },
     "nanomatch": {
       "version": "1.2.13",
       "resolved": "https://registry.npmjs.org/nanomatch/-/nanomatch-1.2.13.tgz",
@@ -11601,6 +11629,11 @@
         "pinkie-promise": "^2.0.0"
       }
     },
+    "picocolors": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/picocolors/-/picocolors-1.0.0.tgz",
+      "integrity": "sha512-1fygroTLlHu66zi26VoTDv8yRgm0Fccecssto+MhsZ0D/DGW2sm8E8AjW7NU5VVTRt5GxbeZ5qBuJr+HyLYkjQ=="
+    },
     "pify": {
       "version": "2.3.0",
       "resolved": "http://registry.npmjs.org/pify/-/pify-2.3.0.tgz",
@@ -11666,14 +11699,13 @@
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-      "version": "5.2.18",
-      "resolved": "https://registry.npmjs.org/postcss/-/postcss-5.2.18.tgz",
-      "integrity": "sha512-zrUjRRe1bpXKsX1qAJNJjqZViErVuyEkMTRrwu4ud4sbTtIBRmtaYDrHmcGgmrbsW3MHfmtIf+vJumgQn+PrXg==",
+      "version": "8.4.31",
+      "resolved": "https://registry.npmjs.org/postcss/-/postcss-8.4.31.tgz",
+      "integrity": "sha512-PS08Iboia9mts/2ygV3eLpY5ghnUcfLV/EXTOW1E2qYxJKGGBUtNjN76FYHnMs36RmARn41bC0AZmn+rR0OVpQ==",
       "requires": {
-        "chalk": "^1.1.3",
-        "js-base64": "^2.1.9",
-        "source-map": "^0.5.6",
-        "supports-color": "^3.2.3"
+        "nanoid": "^3.3.6",
+        "picocolors": "^1.0.0",
+        "source-map-js": "^1.0.2"
       }
     },
     "power-assert-context-formatter": {
@@ -12765,7 +12797,13 @@
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       "resolved": "https://registry.npmjs.org/source-map/-/source-map-0.5.7.tgz",
-      "integrity": "sha1-igOdLRAh0i0eoUyA2OpGi6LvP8w="
+      "integrity": "sha1-igOdLRAh0i0eoUyA2OpGi6LvP8w=",
+      "dev": true
+    },
+    "source-map-js": {
+      "version": "1.2.0",
+      "resolved": "https://registry.npmjs.org/source-map-js/-/source-map-js-1.2.0.tgz",
+      "integrity": "sha512-itJW8lvSA0TXEphiRoawsCksnlf8SyvmFzIhltqAHluXd88pkCd+cXJVHTDwdCr0IzwptSm035IHQktUu1QUMg=="
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     "source-map-resolve": {
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@@ -12909,6 +12947,7 @@
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       "resolved": "https://registry.npmjs.org/strip-ansi/-/strip-ansi-3.0.1.tgz",
       "integrity": "sha1-ajhfuIU9lS1f8F0Oiq+UJ43GPc8=",
+      "dev": true,
       "requires": {
         "ansi-regex": "^2.0.0"
       }
@@ -12937,14 +12976,6 @@
       "integrity": "sha1-PFMZQukIwml8DsNEhYwobHygpgo=",
       "dev": true
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-    "supports-color": {
-      "version": "3.2.3",
-      "resolved": "https://registry.npmjs.org/supports-color/-/supports-color-3.2.3.tgz",
-      "integrity": "sha1-ZawFBLOVQXHYpklGsq48u4pfVPY=",
-      "requires": {
-        "has-flag": "^1.0.0"
-      }
-    },
     "symbol": {
       "version": "0.2.3",
       "resolved": "https://registry.npmjs.org/symbol/-/symbol-0.2.3.tgz",
diff --git a/package.json b/package.json
index e38bf49..3ef868b 100644
--- a/package.json
+++ b/package.json
@@ -32,7 +32,7 @@
   "dependencies": {
     "caniuse-api": "^3.0.0",
     "parse-css-font": "^2.0.2",
-    "postcss": "^5.0.16",
+    "postcss": "^8.4.31",
     "quote": "^0.4.0"
   },
   "devDependencies": {