diff --git a/js/lib/beautify-css.js b/js/lib/beautify-css.js
index 210099123..761e5dee8 100644
--- a/js/lib/beautify-css.js
+++ b/js/lib/beautify-css.js
@@ -315,7 +315,12 @@
                 }
             } else if (ch === ']') {
                 output.push(ch);
-            } else if (ch === '[' || ch === '=') { // no whitespace before or after
+            } else if (ch === '[') {
+                if (isAfterSpace) {
+                    print.singleSpace();
+                }
+                output.push(ch);
+            } else if (ch === '=') { // no whitespace before or after
                 eatWhitespace();
                 output.push(ch);
             } else {
diff --git a/js/test/beautify-tests.js b/js/test/beautify-tests.js
index b6e11b16a..ac3681589 100755
--- a/js/test/beautify-tests.js
+++ b/js/test/beautify-tests.js
@@ -2001,6 +2001,9 @@ function run_beautifier_tests(test_obj, Urlencoded, js_beautify, html_beautify,
         btc("a:not(\"foobar\\\";{}omg\"){\ncontent: 'example\\';{} text';\ncontent: \"example\\\";{} text\";}",
             "a:not(\"foobar\\\";{}omg\") {\n  content: 'example\\';{} text';\n  content: \"example\\\";{} text\";\n}\n");
 
+        btc('html.js [data-custom="123"] {\n  opacity: 1.00;\n}\n'); // may not eat the space before "["
+        btc('html.js *[data-custom="123"] {\n  opacity: 1.00;\n}\n');
+
         return sanitytest;
     }
 
diff --git a/python/cssbeautifier/__init__.py b/python/cssbeautifier/__init__.py
index eee078881..cf978a4ba 100644
--- a/python/cssbeautifier/__init__.py
+++ b/python/cssbeautifier/__init__.py
@@ -285,7 +285,11 @@ def beautify(self):
                     printer.singleSpace()
             elif self.ch == ']':
                 printer.push(self.ch)
-            elif self.ch == '[' or self.ch == '=':
+            elif self.ch == '[':
+                if isAfterSpace:
+                    printer.singleSpace()
+                printer.push(self.ch)
+            elif self.ch == '=':
                 # no whitespace before or after
                 self.eatWhitespace()
                 printer.push(self.ch)
diff --git a/python/cssbeautifier/tests/test.py b/python/cssbeautifier/tests/test.py
index 6e8c8b480..a270ec4f0 100644
--- a/python/cssbeautifier/tests/test.py
+++ b/python/cssbeautifier/tests/test.py
@@ -23,6 +23,10 @@ def testBasics(self):
         t("#bla, #foo{color:red}", "#bla,\n#foo {\n\tcolor: red\n}\n")
         t("@media print {.tab{}}", "@media print {\n\t.tab {}\n}\n")
 
+        # may not eat the space before "["
+        t('html.js [data-custom="123"] {\n\topacity: 1.00;\n}\n'); 
+        t('html.js *[data-custom="123"] {\n\topacity: 1.00;\n}\n');
+
 
     def testComments(self):
         self.resetOptions()