diff --git a/History.md b/History.md
index 9b8089e5..8336afd2 100644
--- a/History.md
+++ b/History.md
@@ -1,3 +1,9 @@
+[5.3.1 / 2022-07-13](https://github.com/clean-css/clean-css/compare/v5.3.0...v5.3.1)
+==================
+
+* Fixed issue [#1218](https://github.com/clean-css/clean-css/issues/1218) - double hyphen in at-rule breaks parsing.
+* Fixed issue [#1220](https://github.com/clean-css/clean-css/issues/1220) - adds optimization for nth-* rules.
+
 [5.3.0 / 2022-03-31](https://github.com/clean-css/clean-css/compare/v5.2.3...v5.3.0)
 ==================
 
diff --git a/lib/optimizer/level-1/tidy-rules.js b/lib/optimizer/level-1/tidy-rules.js
index c0399886..bb467e29 100644
--- a/lib/optimizer/level-1/tidy-rules.js
+++ b/lib/optimizer/level-1/tidy-rules.js
@@ -193,7 +193,13 @@ function replacePseudoClasses(value) {
     .replace('nth-of-type(even)', 'nth-of-type(2n)')
     .replace('nth-child(even)', 'nth-child(2n)')
     .replace('nth-of-type(2n+1)', 'nth-of-type(odd)')
-    .replace('nth-child(2n+1)', 'nth-child(odd)');
+    .replace('nth-child(2n+1)', 'nth-child(odd)')
+    .replace('nth-last-child(1)', 'last-child')
+    .replace('nth-last-of-type(1)', 'last-of-type')
+    .replace('nth-last-of-type(even)', 'nth-last-of-type(2n)')
+    .replace('nth-last-child(even)', 'nth-last-child(2n)')
+    .replace('nth-last-of-type(2n+1)', 'nth-last-of-type(odd)')
+    .replace('nth-last-child(2n+1)', 'nth-last-child(odd)');
 }
 
 function tidyRules(rules, removeUnsupported, adjacentSpace, format, warnings) {
diff --git a/lib/tokenizer/tokenize.js b/lib/tokenizer/tokenize.js
index 07575b8f..0331012c 100644
--- a/lib/tokenizer/tokenize.js
+++ b/lib/tokenizer/tokenize.js
@@ -373,6 +373,7 @@ function intoTokens(source, externalContext, internalContext, isNested) {
       position.index++;
       buffer = [];
       isBufferEmpty = true;
+      isVariable = false;
 
       ruleToken[2] = intoTokens(source, externalContext, internalContext, true);
       ruleToken = null;
diff --git a/package-lock.json b/package-lock.json
index f3a2242b..ab298be1 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "clean-css",
-  "version": "5.3.0",
+  "version": "5.3.1",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/package.json b/package.json
index 7ac4ead2..686ce862 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "clean-css",
-  "version": "5.3.0",
+  "version": "5.3.1",
   "author": "Jakub Pawlowicz <contact@jakubpawlowicz.com>",
   "description": "A well-tested CSS minifier",
   "license": "MIT",
diff --git a/test/optimizer/level-1/optimize-test.js b/test/optimizer/level-1/optimize-test.js
index 4667498d..0723c0dc 100644
--- a/test/optimizer/level-1/optimize-test.js
+++ b/test/optimizer/level-1/optimize-test.js
@@ -74,6 +74,30 @@ vows.describe('level 1 optimizations')
         '.block:nth-child(2n+1){color:red}',
         '.block:nth-child(odd){color:red}'
       ],
+      'pseudo classes - nth-last-child(1) to last-child': [
+        '.block:nth-last-child(1){color:red}',
+        '.block:last-child{color:red}'
+      ],
+      'pseudo classes - nth-last-of-type(1) to last-of-type': [
+        '.block:nth-last-of-type(1){color:red}',
+        '.block:last-of-type{color:red}'
+      ],
+      'pseudo classes - nth-last-of-type(even) to nth-last-of-type(2n)': [
+        '.block:nth-last-of-type(even){color:red}',
+        '.block:nth-last-of-type(2n){color:red}'
+      ],
+      'pseudo classes - nth-last-child(even) to nth-last-child(2n)': [
+        '.block:nth-last-child(even){color:red}',
+        '.block:nth-last-child(2n){color:red}'
+      ],
+      'pseudo classes - nth-last-of-type(2n+1) to nth-last-of-type(odd)': [
+        '.block:nth-last-of-type(2n+1){color:red}',
+        '.block:nth-last-of-type(odd){color:red}'
+      ],
+      'pseudo classes - nth-last-child(2n+1) to nth-last-child(odd)': [
+        '.block:nth-last-child(2n+1){color:red}',
+        '.block:nth-last-child(odd){color:red}'
+      ],
       'tabs': [
         'div\t\t{color:red}',
         'div{color:red}'