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diff --git a/src/nodejs/postprocessor.js b/src/nodejs/postprocessor.js
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+/*eslint-env node */
+/*!
+ * Postprocessor for shimming @media (hover: hover) from Media Queries Level 4
+ * https://github.com/cvrebert/mq4-hover-hover-shim
+ * Copyright 2014 Christopher Rebert
+ * Licensed under MIT (https://github.com/cvrebert/mq4-hover-hover-shim/blob/master/LICENSE.txt)
+ */
+
+'use strict';
+
+var postcss = require('postcss');
+var mediaQuery = require('css-mediaquery');
+
+
+// Checks whether the at-rule is: @media (hover: hover) {...}
+function isSimpleMediaHoverHover(atRule) {
+    var mediaOrs = mediaQuery.parse(atRule.params);
+    if (mediaOrs.length > 1) {
+        return false;
+    }
+    var mediaAnds = mediaOrs[0];
+    if (mediaAnds.inverse) {
+        return false;
+    }
+    if (mediaAnds.expressions.length > 1) {
+        return false;
+    }
+    var mediaExpr = mediaAnds.expressions[0];
+    return mediaExpr.feature === 'hover' && mediaExpr.value === 'hover';
+}
+
+function replaceWithItsChildren(atRule) {
+    atRule.each(function (child) {
+        child.moveBefore(atRule);
+    });
+    atRule.removeSelf();
+}
+
+// Prefixes each selector in the given rule with the given prefix string
+function prefixSelectorsWith(rule, selectorPrefix) {
+    // Yes, this parsing is horribly naive.
+
+    // We don't use rule.selectors because it's "some kind of hack" per https://github.com/postcss/postcss/issues/37
+    // and it doesn't preserve inter-selector whitespace.
+    var selectorsWithWhitespace = rule.selector.split(',');
+
+    var revisedSelectors = selectorsWithWhitespace.map(function (selectorWithWhitespace) {
+        var quadruple = /^(\s*)(\S.*\S)(\s*)$/.exec(selectorWithWhitespace);
+        if (quadruple === null) {
+            // Skip weirdness
+            return selectorWithWhitespace;
+        }
+
+        var prefixWhitespace = quadruple[1];
+        var selector = quadruple[2];
+        var suffixWhitespace = quadruple[3];
+
+        var revisedSelector = prefixWhitespace + selectorPrefix + selector + suffixWhitespace;
+        return revisedSelector;
+    });
+    rule.selector = revisedSelectors.join(',');
+}
+
+
+module.exports = postcss(function process(css, opts) {
+    var hoverSelectorPrefix = opts.hoverSelectorPrefix;
+    if ((typeof hoverSelectorPrefix) !== 'string') {
+        throw new Error('hoverSelectorPrefix option must be a string');
+    }
+
+    css.eachAtRule('media', function (atRule) {
+        if (!isSimpleMediaHoverHover(atRule)) {
+            return;
+        }
+
+        atRule.eachRule(function (rule) {
+            prefixSelectorsWith(rule, hoverSelectorPrefix);
+        });
+
+        replaceWithItsChildren(atRule);
+    });
+});