diff --git a/src/main/java/org/owasp/validator/css/CssHandler.java b/src/main/java/org/owasp/validator/css/CssHandler.java
index 7be3875..5bcca30 100644
--- a/src/main/java/org/owasp/validator/css/CssHandler.java
+++ b/src/main/java/org/owasp/validator/css/CssHandler.java
@@ -35,6 +35,10 @@
 import java.util.LinkedList;
 import java.util.List;
 import java.util.ResourceBundle;
+import org.owasp.validator.css.media.CssMediaFeature;
+import org.owasp.validator.css.media.CssMediaQuery;
+import org.owasp.validator.css.media.CssMediaQueryList;
+import org.owasp.validator.css.media.CssMediaType;
 import org.owasp.validator.html.InternalPolicy;
 import org.owasp.validator.html.Policy;
 import org.owasp.validator.html.ScanException;
@@ -96,6 +100,10 @@ public class CssHandler implements DocumentHandler {
    */
   private boolean selectorOpen = false;
 
+  private MediaState mediaState = MediaState.OUTSIDE;
+
+  private enum MediaState {INSIDE, OUTSIDE, DENIED}
+
   /**
    * Constructs a handler for stylesheets using the given policy. The List of embedded stylesheets
    * produced by this constructor is now available via the getImportedStylesheetsURIList() method.
@@ -340,26 +348,6 @@ public void endFontFace() throws CSSException {
     // CSS2 Font Face declaration - ignore this for now
   }
 
-  /*
-   * (non-Javadoc)
-   *
-   * @see org.w3c.css.sac.DocumentHandler#startMedia(org.w3c.css.sac.SACMediaList)
-   */
-  @Override
-  public void startMedia(SACMediaList media) throws CSSException {
-    // CSS2 Media declaration - ignore this for now
-  }
-
-  /*
-   * (non-Javadoc)
-   *
-   * @see org.w3c.css.sac.DocumentHandler#endMedia(org.w3c.css.sac.SACMediaList)
-   */
-  @Override
-  public void endMedia(SACMediaList media) throws CSSException {
-    // CSS2 Media declaration - ignore this for now
-  }
-
   /*
    * (non-Javadoc)
    *
@@ -538,4 +526,56 @@ public void property(String name, LexicalUnit value, boolean important) throws C
               }));
     }
   }
+
+  @Override
+  public void startMedia(SACMediaList media) throws CSSException {
+    CssMediaQueryList mediaQueryList = (CssMediaQueryList) media;
+
+    boolean first = true;
+    for (CssMediaQuery query : mediaQueryList.getMediaQueries()) {
+      if (!validator.isValidMediaQuery(query)) {
+        continue;
+      }
+      if (first) {
+        styleSheet.append("@media ");
+        first = false;
+      } else {
+        styleSheet.append(", ");
+      }
+      if (query.getLogicalOperator() != null) {
+        styleSheet.append(query.getLogicalOperator()).append(' ');
+      }
+      styleSheet.append(query.getMediaType());
+      for (CssMediaFeature feature : query.getMediaFeatures()) {
+        if (feature == query.getMediaFeatures().get(0) && query.getMediaType() == CssMediaType.IMPLIED_ALL) {
+          styleSheet.append("(");
+        } else {
+          styleSheet.append(" and (");
+        }
+        styleSheet.append(feature.getName());
+        if (feature.getExpression() != null) {
+          styleSheet.append(": ");
+          styleSheet.append(validator.lexicalValueToString(feature.getExpression()));
+        }
+        styleSheet.append(')');
+      }
+    }
+
+    if (!first) {
+      styleSheet.append(" {");
+      styleSheet.append('\n');
+      mediaState = MediaState.INSIDE;
+    } else {
+      mediaState = MediaState.DENIED;
+    }
+  }
+
+  @Override
+  public void endMedia(SACMediaList media) throws CSSException {
+    if (mediaState == MediaState.INSIDE) {
+      styleSheet.append('}');
+      styleSheet.append('\n');
+    }
+    mediaState = MediaState.OUTSIDE;
+  }
 }
diff --git a/src/main/java/org/owasp/validator/css/CssParser.java b/src/main/java/org/owasp/validator/css/CssParser.java
index 832f6c9..590f6ea 100644
--- a/src/main/java/org/owasp/validator/css/CssParser.java
+++ b/src/main/java/org/owasp/validator/css/CssParser.java
@@ -28,7 +28,16 @@
  */
 package org.owasp.validator.css;
 
+import static org.owasp.validator.css.media.CssMediaQueryLogicalOperator.AND;
+import static org.owasp.validator.css.media.CssMediaQueryLogicalOperator.OR;
+
+import org.apache.batik.css.parser.CSSSACMediaList;
 import org.apache.batik.css.parser.LexicalUnits;
+import org.owasp.validator.css.media.CssMediaFeature;
+import org.owasp.validator.css.media.CssMediaQuery;
+import org.owasp.validator.css.media.CssMediaQueryList;
+import org.owasp.validator.css.media.CssMediaQueryLogicalOperator;
+import org.owasp.validator.css.media.CssMediaType;
 import org.w3c.css.sac.CSSException;
 import org.w3c.css.sac.CSSParseException;
 import org.w3c.css.sac.LexicalUnit;
@@ -96,4 +105,149 @@ protected void parseStyleDeclaration(final boolean inSheet) throws CSSException
       }
     }
   }
+
+  @Override
+  protected CSSSACMediaList parseMediaList() {
+    CssMediaQueryList mediaList = new CssMediaQueryList();
+
+    mediaList.append(parseMediaQuery());
+    while (hasAnotherMediaQuery()) {
+      nextIgnoreSpaces();
+      mediaList.append(parseMediaQuery());
+    }
+
+    return mediaList;
+  }
+
+  private boolean hasAnotherMediaQuery() {
+    return current == LexicalUnits.COMMA || (current == LexicalUnits.IDENTIFIER && scanner.getStringValue().equals(OR.toString()));
+  }
+
+  protected CssMediaQuery parseMediaQuery() {
+    CssMediaQuery query = new CssMediaQuery();
+    CssMediaType mediaType = null;
+    CssMediaQueryLogicalOperator logicalOperator = null;
+    switch (current) {
+      case LexicalUnits.LEFT_BRACE:
+        mediaType = CssMediaType.IMPLIED_ALL;
+        break;
+      case LexicalUnits.IDENTIFIER:
+        logicalOperator = CssMediaQueryLogicalOperator.parse(scanner.getStringValue());
+        if (logicalOperator != null) {
+          switch (logicalOperator) {
+            case ONLY:
+              parseLogicalOperatorOnly();
+              mediaType = parseMediaType();
+              break;
+            case NOT:
+              mediaType = parseLogicalOperatorNot();
+              break;
+            case AND:
+            case OR:
+            case COMMA:
+              throw createCSSParseException("identifier");
+          }
+        } else {
+          mediaType = parseMediaType();
+        }
+        break;
+      default:
+        throw createCSSParseException("identifier");
+    }
+    query.setMediaType(mediaType);
+    query.setLogicalOperator(logicalOperator);
+
+    if (mediaType == CssMediaType.IMPLIED_ALL) {
+      query.addMediaFeature(parseMediaFeature());
+    }
+
+    while (current == LexicalUnits.IDENTIFIER && CssMediaQueryLogicalOperator.parse(scanner.getStringValue()) == AND) {
+      nextIgnoreSpaces();
+      query.addMediaFeature(parseMediaFeature());
+    }
+    return query;
+  }
+
+  private CssMediaType parseMediaType() {
+    CssMediaType mediaType;
+    mediaType = CssMediaType.parse(scanner.getStringValue());
+    if (mediaType == null) {
+      throw createCSSParseException("identifier");
+    }
+    nextIgnoreSpaces();
+    return mediaType;
+  }
+
+  private CssMediaType parseLogicalOperatorNot() {
+    CssMediaType mediaType;
+    if (nextIgnoreSpaces() == LexicalUnits.IDENTIFIER) {
+      mediaType = parseMediaType();
+    } else {
+      mediaType = CssMediaType.IMPLIED_ALL;
+    }
+    return mediaType;
+  }
+
+  private void parseLogicalOperatorOnly() {
+    if (nextIgnoreSpaces() != LexicalUnits.IDENTIFIER) {
+      throw createCSSParseException("identifier");
+    }
+  }
+
+  protected CssMediaFeature parseMediaFeature() {
+    if (current != LexicalUnits.LEFT_BRACE) {
+      throw createCSSParseException("'(' expected.");
+    }
+    nextIgnoreSpaces();
+    String namePrefix = "";
+    if (current == LexicalUnits.MINUS) {
+      nextIgnoreSpaces();
+      namePrefix = "-";
+    }
+    if (current != LexicalUnits.IDENTIFIER) {
+      throw createCSSParseException("identifier");
+    }
+    String name = namePrefix + scanner.getStringValue();
+    nextIgnoreSpaces();
+    LexicalUnit exp = null;
+    if (current == LexicalUnits.COLON) {
+      nextIgnoreSpaces();
+      exp = parseTerm(null);
+    }
+    if (current != LexicalUnits.RIGHT_BRACE) {
+      throw createCSSParseException("')' expected.");
+    }
+    nextIgnoreSpaces();
+
+    return new CssMediaFeature(name, exp);
+  }
+
+  @Override
+  protected void parseMediaRule() {
+    CSSSACMediaList ml = parseMediaList();
+    try {
+      documentHandler.startMedia(ml);
+
+      if (current != LexicalUnits.LEFT_CURLY_BRACE) {
+        reportError("left.curly.brace");
+      } else {
+        nextIgnoreSpaces();
+
+        loop:
+        for (; ; ) {
+          switch (current) {
+            case LexicalUnits.EOF:
+            case LexicalUnits.RIGHT_CURLY_BRACE:
+              break loop;
+            default:
+              parseRuleSet();
+          }
+        }
+
+        nextIgnoreSpaces();
+      }
+    } finally {
+      documentHandler.endMedia(ml);
+    }
+  }
 }
diff --git a/src/main/java/org/owasp/validator/css/CssValidator.java b/src/main/java/org/owasp/validator/css/CssValidator.java
index d9547ba..8f6c07b 100644
--- a/src/main/java/org/owasp/validator/css/CssValidator.java
+++ b/src/main/java/org/owasp/validator/css/CssValidator.java
@@ -31,6 +31,9 @@
 import java.text.DecimalFormat;
 import java.util.Iterator;
 import java.util.regex.Pattern;
+import org.apache.batik.css.parser.CSSLexicalUnit;
+import org.owasp.validator.css.media.CssMediaFeature;
+import org.owasp.validator.css.media.CssMediaQuery;
 import org.owasp.validator.html.Policy;
 import org.owasp.validator.html.ScanException;
 import org.owasp.validator.html.model.AntiSamyPattern;
@@ -56,6 +59,8 @@
  */
 public class CssValidator {
 
+  private static final LexicalUnit EMPTYSTRINGLEXICALUNIT = CSSLexicalUnit.createString(LexicalUnit.SAC_STRING_VALUE, "", null);
+
   private final Policy policy;
 
   /**
@@ -406,6 +411,45 @@ public String lexicalValueToString(LexicalUnit lu) {
     }
   }
 
+  /**
+   * Returns whether the given {@link CssMediaQuery} is valid
+   *
+   * @param mediaQuery mediaQuery
+   * @return valid mediaQuery?
+   */
+  public boolean isValidMediaQuery(CssMediaQuery mediaQuery) {
+    // check mediaType against allowed media-HTML-Attribute
+    Property mediatype = policy.getPropertyByName("_mediatype");
+    if (mediatype == null) {
+      return false;
+    }
+
+    String mediaTypeString = mediaQuery.getMediaType().toString().toLowerCase();
+    boolean isRegExpAllowed = false;
+    for (Pattern pattern : mediatype.getAllowedRegExp()) {
+      isRegExpAllowed |= pattern.matcher(mediaTypeString).matches();
+    }
+    boolean isValidMediaType = mediatype.getAllowedValues().contains(mediaTypeString) || isRegExpAllowed;
+    if (!isValidMediaType) {
+      return false;
+    }
+
+    for (CssMediaFeature feature : mediaQuery.getMediaFeatures()) {
+      LexicalUnit expression = feature.getExpression();
+      if (expression == null) {
+        expression = EMPTYSTRINGLEXICALUNIT;
+      }
+      if (!isValidMediaFeature(feature.getName(), expression)) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  private boolean isValidMediaFeature(String name, LexicalUnit lu) {
+    return isValidProperty("_mediafeature_" + name, lu);
+  }
+
   /**
    * Returns color value as int.
    * Maps percentages to values between 0 and 255.
diff --git a/src/main/java/org/owasp/validator/css/media/CssMediaFeature.java b/src/main/java/org/owasp/validator/css/media/CssMediaFeature.java
new file mode 100644
index 0000000..f4a34c5
--- /dev/null
+++ b/src/main/java/org/owasp/validator/css/media/CssMediaFeature.java
@@ -0,0 +1,28 @@
+package org.owasp.validator.css.media;
+
+import org.w3c.css.sac.LexicalUnit;
+
+public class CssMediaFeature {
+
+    private final String name;
+    private final LexicalUnit expression;
+
+    /**
+     * Constructor.
+     *
+     * @param name Feature-name
+     * @param expression expression, may be null
+     */
+    public CssMediaFeature(String name, LexicalUnit expression) {
+        this.name = name;
+        this.expression = expression;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public LexicalUnit getExpression() {
+        return expression;
+    }
+}
diff --git a/src/main/java/org/owasp/validator/css/media/CssMediaQuery.java b/src/main/java/org/owasp/validator/css/media/CssMediaQuery.java
new file mode 100644
index 0000000..6005200
--- /dev/null
+++ b/src/main/java/org/owasp/validator/css/media/CssMediaQuery.java
@@ -0,0 +1,36 @@
+package org.owasp.validator.css.media;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+public class CssMediaQuery {
+
+    private CssMediaQueryLogicalOperator logicalOperator;
+    private CssMediaType mediaType;
+    private final List<CssMediaFeature> mediaFeatures = new ArrayList<>();
+
+    public CssMediaQueryLogicalOperator getLogicalOperator() {
+        return logicalOperator;
+    }
+
+    public void setLogicalOperator(CssMediaQueryLogicalOperator logicalOperator) {
+        this.logicalOperator = logicalOperator;
+    }
+
+    public CssMediaType getMediaType() {
+        return mediaType;
+    }
+
+    public void setMediaType(CssMediaType mediaType) {
+        this.mediaType = mediaType;
+    }
+
+    public void addMediaFeature(CssMediaFeature mediaFeature) {
+        mediaFeatures.add(mediaFeature);
+    }
+
+    public List<CssMediaFeature> getMediaFeatures() {
+        return Collections.unmodifiableList(mediaFeatures);
+    }
+}
diff --git a/src/main/java/org/owasp/validator/css/media/CssMediaQueryList.java b/src/main/java/org/owasp/validator/css/media/CssMediaQueryList.java
new file mode 100644
index 0000000..52fe815
--- /dev/null
+++ b/src/main/java/org/owasp/validator/css/media/CssMediaQueryList.java
@@ -0,0 +1,44 @@
+package org.owasp.validator.css.media;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+import org.apache.batik.css.parser.CSSSACMediaList;
+
+public class CssMediaQueryList extends CSSSACMediaList {
+
+    private final List<CssMediaQuery> mediaQueries = new ArrayList<>();
+
+    @Override
+    public int getLength() {
+        return mediaQueries.size();
+    }
+
+    /**
+     * Use {@link CssMediaQueryList#getMediaQueryAt(int)} instead.
+     * {@inheritDoc}
+     */
+    @Override
+    public String item(int index) {
+        CssMediaQuery query = getMediaQueryAt(index);
+        if (query.getMediaFeatures().isEmpty() && query.getLogicalOperator() == null) {
+            return query.getMediaType().toString();
+        } else {
+            throw new UnsupportedOperationException("CSS3 MediaQuery unsupported");
+        }
+    }
+
+    public CssMediaQuery getMediaQueryAt(int index) {
+        return mediaQueries.get(index);
+    }
+
+    public List<CssMediaQuery> getMediaQueries() {
+        return Collections.unmodifiableList(mediaQueries);
+    }
+
+
+    public void append(CssMediaQuery mediaQuery) {
+        mediaQueries.add(mediaQuery);
+    }
+}
diff --git a/src/main/java/org/owasp/validator/css/media/CssMediaQueryLogicalOperator.java b/src/main/java/org/owasp/validator/css/media/CssMediaQueryLogicalOperator.java
new file mode 100644
index 0000000..58d1d60
--- /dev/null
+++ b/src/main/java/org/owasp/validator/css/media/CssMediaQueryLogicalOperator.java
@@ -0,0 +1,25 @@
+package org.owasp.validator.css.media;
+
+public enum CssMediaQueryLogicalOperator {
+    AND("and"), NOT("not"), ONLY("only"), OR("or"), COMMA(",");
+
+    public final String label;
+
+    CssMediaQueryLogicalOperator(String label) {
+        this.label = label;
+    }
+
+    @Override
+    public String toString() {
+        return label;
+    }
+
+    public static CssMediaQueryLogicalOperator parse(String operator) {
+        for (CssMediaQueryLogicalOperator element : values()) {
+            if (element.label.equalsIgnoreCase(operator)) {
+                return element;
+            }
+        }
+        return null;
+    }
+}
diff --git a/src/main/java/org/owasp/validator/css/media/CssMediaType.java b/src/main/java/org/owasp/validator/css/media/CssMediaType.java
new file mode 100644
index 0000000..8f70a84
--- /dev/null
+++ b/src/main/java/org/owasp/validator/css/media/CssMediaType.java
@@ -0,0 +1,25 @@
+package org.owasp.validator.css.media;
+
+public enum CssMediaType {
+    ALL("all"), PRINT("print"), SCREEN("screen"), IMPLIED_ALL("");
+
+    public final String label;
+
+    CssMediaType(String label) {
+        this.label = label;
+    }
+
+    @Override
+    public String toString() {
+        return label;
+    }
+
+    public static CssMediaType parse(String mediaType) {
+        for (CssMediaType element : values()) {
+            if (element.toString().equalsIgnoreCase(mediaType)) {
+                return element;
+            }
+        }
+        return null;
+    }
+}
diff --git a/src/main/resources/antisamy-anythinggoes.xml b/src/main/resources/antisamy-anythinggoes.xml
index 1c3b330..52a39a2 100644
--- a/src/main/resources/antisamy-anythinggoes.xml
+++ b/src/main/resources/antisamy-anythinggoes.xml
@@ -97,6 +97,8 @@
         <regexp name="positiveLength" value="((\+)?0|(\+)?([0-9]+(\.[0-9]+)?([eE][+-]?[0-9]+)?)(rem|vw|vh|em|ex|px|in|cm|mm|pt|pc))" />
         <regexp name="percentage" value="(-|\+)?([0-9]+(\.[0-9]+)?)%" />
         <regexp name="positivePercentage" value="(\+)?([0-9]+(\.[0-9]+)?)%" />
+        <regexp name="ratio" value="[0-9]+/[0-9]+"/>
+        <regexp name="resolution" value="((\+)?0|(\+)?([0-9]+(\.[0-9]+)?)(dpi|dpcm|dppx|x))"/>
 
         <regexp name="absolute-size" value="(xx-small|x-small|small|medium|large|x-large|xx-large)" />
         <regexp name="relative-size" value="(larger|smaller)" />
@@ -2612,6 +2614,479 @@
                 <literal value="inherit" />
             </literal-list>
         </property>
+
+        <property name="_mediafeature_any-hover" description="Does any available input mechanism allow the user to hover over elements?">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <literal-list>
+                <literal value="none"/>
+                <literal value="hover"/>
+            </literal-list>
+        </property>
+
+        <property name="_mediatype" description="Describes the general category of a device">
+            <literal-list>
+                <literal value="all"/>
+                <literal value="print"/>
+                <literal value="screen"/>
+                <literal value=""/>
+            </literal-list>
+        </property>
+
+        <property name="_mediafeature_any-pointer" description="Is any available input mechanism a pointing device, and if so, how accurate is it?">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <literal-list>
+                <literal value="none"/>
+                <literal value="coarse"/>
+                <literal value="fine"/>
+            </literal-list>
+        </property>
+
+        <property name="_mediafeature_aspect-ratio" description="Width-to-height aspect ratio of the viewport.">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <regexp-list>
+                <regexp name="ratio"/>
+                <regexp name="number"/>
+            </regexp-list>
+        </property>
+
+        <property name="_mediafeature_color" description="Number of bits per color component of the output device, or zero if the device isn't color.">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <literal-list>
+                <literal value=""/>
+            </literal-list>
+            <regexp-list>
+                <regexp name="integer"/>
+            </regexp-list>
+        </property>
+        <property name="_mediafeature_min-color" description="">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <regexp-list>
+                <regexp name="integer"/>
+            </regexp-list>
+        </property>
+        <property name="_mediafeature_max-color" description="">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <regexp-list>
+                <regexp name="integer"/>
+            </regexp-list>
+        </property>
+
+        <property name="_mediafeature_color-gamut" description="Approximate range of colors that are supported by the user agent and output device.">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <literal-list>
+                <literal value="srgb"/>
+                <literal value="p3"/>
+                <literal value="rec2020"/>
+            </literal-list>
+        </property>
+
+        <property name="_mediafeature_color-index" description="Number of entries in the output device's color lookup table, or zero if the device does not use such a table.">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <literal-list>
+                <literal value=""/>
+            </literal-list>
+            <regexp-list>
+                <regexp name="integer"/>
+            </regexp-list>
+        </property>
+        <property name="_mediafeature_min-color-index" description="">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <regexp-list>
+                <regexp name="integer"/>
+            </regexp-list>
+        </property>
+        <property name="_mediafeature_max-color-index" description="">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <regexp-list>
+                <regexp name="integer"/>
+            </regexp-list>
+        </property>
+
+        <property name="_mediafeature_device-aspect-ratio" description="Width-to-height aspect ratio of the output device. Deprecated in Media Queries Level 4.">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <regexp-list>
+                <regexp name="ratio"/>
+                <regexp name="number"/>
+            </regexp-list>
+        </property>
+
+        <property name="_mediafeature_device-height" description="Height of the rendering surface of the output device. Deprecated in Media Queries Level 4.">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <regexp-list>
+                <regexp name="positiveLength"/>
+            </regexp-list>
+        </property>
+        <property name="_mediafeature_min-device-height" description="">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <regexp-list>
+                <regexp name="positiveLength"/>
+            </regexp-list>
+        </property>
+        <property name="_mediafeature_max-device-height" description="">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <regexp-list>
+                <regexp name="positiveLength"/>
+            </regexp-list>
+        </property>
+
+        <property name="_mediafeature_device-width" description="Width of the rendering surface of the output device. Deprecated in Media Queries Level 4.">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <regexp-list>
+                <regexp name="positiveLength"/>
+            </regexp-list>
+        </property>
+        <property name="_mediafeature_min-device-width" description="">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <regexp-list>
+                <regexp name="positiveLength"/>
+            </regexp-list>
+        </property>
+        <property name="_mediafeature_max-device-width" description="">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <regexp-list>
+                <regexp name="positiveLength"/>
+            </regexp-list>
+        </property>
+
+        <property name="_mediafeature_display-mode" description="The mode in which an application is being displayed: for example, fullscreen or picture-in-picture mode. Added in Media Queries Level 5.">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <literal-list>
+                <literal value="browser"/>
+                <literal value="fullscreen"/>
+                <literal value="minimal-ui"/>
+                <literal value="picture-in-picture"/>
+                <literal value="standalone"/>
+                <literal value="window-controls-overlay"/>
+            </literal-list>
+        </property>
+
+        <property name="_mediafeature_dynamic-range" description="Combination of brightness, contrast ratio, and color depth that are supported by the user agent and the output device. Added in Media Queries Level 5.">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <literal-list>
+                <literal value="standard"/>
+                <literal value="high"/>
+            </literal-list>
+        </property>
+
+        <property name="_mediafeature_forced-colors" description="Detect whether user agent restricts color palette. Added in Media Queries Level 5.">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <literal-list>
+                <literal value="none"/>
+                <literal value="active"/>
+            </literal-list>
+        </property>
+
+        <property name="_mediafeature_grid" description="Does the device use a grid or bitmap screen?">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <literal-list>
+                <literal value=""/>
+                <literal value="-0"/>
+                <literal value="0"/>
+                <literal value="1"/>
+            </literal-list>
+        </property>
+
+        <property name="_mediafeature_height" description="Height of the viewport.">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <regexp-list>
+                <regexp name="positiveLength"/>
+            </regexp-list>
+        </property>
+        <property name="_mediafeature_min-height" description="">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <regexp-list>
+                <regexp name="positiveLength"/>
+            </regexp-list>
+        </property>
+        <property name="_mediafeature_max-height" description="">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <regexp-list>
+                <regexp name="positiveLength"/>
+            </regexp-list>
+        </property>
+
+        <property name="_mediafeature_hover" description="Does the primary input mechanism allow the user to hover over elements?">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <literal-list>
+                <literal value="none"/>
+                <literal value="hover"/>
+            </literal-list>
+        </property>
+
+        <property name="_mediafeature_inverted-colors" description="Is the user agent or underlying OS inverting colors? Added in Media Queries Level 5.">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <literal-list>
+                <literal value="none"/>
+                <literal value="inverted"/>
+            </literal-list>
+        </property>
+
+        <property name="_mediafeature_monochrome" description="Bits per pixel in the output device's monochrome frame buffer, or zero if the device isn't monochrome.">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <literal-list>
+                <literal value=""/>
+            </literal-list>
+            <regexp-list>
+                <regexp name="integer"/>
+            </regexp-list>
+        </property>
+        <property name="_mediafeature_min-monochrome" description="">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <regexp-list>
+                <regexp name="integer"/>
+            </regexp-list>
+        </property>
+        <property name="_mediafeature_max-monochrome" description="">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <regexp-list>
+                <regexp name="integer"/>
+            </regexp-list>
+        </property>
+
+        <property name="_mediafeature_orientation" description="Orientation of the viewport.">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <literal-list>
+                <literal value="portrait"/>
+                <literal value="landscape"/>
+            </literal-list>
+        </property>
+
+        <property name="_mediafeature_overflow-block" description="How does the output device handle content that overflows the viewport along the block axis?">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <literal-list>
+                <literal value="none"/>
+                <literal value="scroll"/>
+                <literal value="optional-paged"/>
+                <literal value="paged"/>
+            </literal-list>
+        </property>
+
+        <property name="_mediafeature_overflow-inline" description="Can content that overflows the viewport along the inline axis be scrolled?">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <literal-list>
+                <literal value="none"/>
+                <literal value="scroll"/>
+            </literal-list>
+        </property>
+
+        <property name="_mediafeature_pointer" description="Is the primary input mechanism a pointing device, and if so, how accurate is it?">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <literal-list>
+                <literal value="none"/>
+                <literal value="coarse"/>
+                <literal value="fine"/>
+            </literal-list>
+        </property>
+
+        <property name="_mediafeature_prefers-color-scheme" description="Detect if the user prefers a light or dark color scheme. Added in Media Queries Level 5.">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <literal-list>
+                <literal value="light"/>
+                <literal value="dark"/>
+            </literal-list>
+        </property>
+
+        <property name="_mediafeature_prefers-contrast" description="Detects if the user has requested the system increase or decrease the amount of contrast between adjacent colors. Added in Media Queries Level 5.">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <literal-list>
+                <literal value="no-preference"/>
+                <literal value="more"/>
+                <literal value="less"/>
+                <literal value="custom"/>
+            </literal-list>
+        </property>
+
+        <property name="_mediafeature_prefers-reduced-motion" description="Detects if the user has requested the web content that consumes less internet traffic.">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <literal-list>
+                <literal value="no-preference"/>
+                <literal value="reduce"/>
+            </literal-list>
+        </property>
+
+        <property name="_mediafeature_prefers-reduced-transparency" description="The user prefers less motion on the page. Added in Media Queries Level 5.">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <literal-list>
+                <literal value="no-preference"/>
+                <literal value="reduce"/>
+            </literal-list>
+        </property>
+
+        <property name="_mediafeature_resolution" description="Detects if a user has enabled a setting on their device to reduce the transparent or translucent layer effects used on the device.">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <regexp-list>
+                <regexp name="resolution"/>
+            </regexp-list>
+        </property>
+        <property name="_mediafeature_min-resolution" description="">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <regexp-list>
+                <regexp name="resolution"/>
+            </regexp-list>
+        </property>
+        <property name="_mediafeature_max-resolution" description="">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <regexp-list>
+                <regexp name="resolution"/>
+            </regexp-list>
+        </property>
+
+        <property name="_mediafeature_scan" description="Whether display output is progressive or interlaced.">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <literal-list>
+                <literal value="interlace"/>
+                <literal value="progressive"/>
+            </literal-list>
+        </property>
+
+        <property name="_mediafeature_scripting" description="Detects whether scripting (i.e. JavaScript) is available. Added in Media Queries Level 5.">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <literal-list>
+                <literal value="none"/>
+                <literal value="initial-only"/>
+                <literal value="enabled"/>
+            </literal-list>
+        </property>
+
+        <property name="_mediafeature_shape" description="Detects the shape of the device to distinguish rectangular and round displays.">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <literal-list>
+                <literal value="rect"/>
+                <literal value="round"/>
+            </literal-list>
+        </property>
+
+        <property name="_mediafeature_update" description="How frequently the output device can modify the appearance of content.">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <literal-list>
+                <literal value="none"/>
+                <literal value="slow"/>
+                <literal value="fast"/>
+            </literal-list>
+        </property>
+
+        <property name="_mediafeature_video-dynamic-range" description="Combination of brightness, contrast ratio, and color depth that are supported by the video plane of user agent and the output device. Added in Media Queries Level 5.">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <literal-list>
+                <literal value="standard"/>
+                <literal value="high"/>
+            </literal-list>
+        </property>
+
+        <property name="_mediafeature_width" description="Width of the viewport including width of scrollbar.">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <regexp-list>
+                <regexp name="positiveLength"/>
+            </regexp-list>
+        </property>
+        <property name="_mediafeature_min-width" description="">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <regexp-list>
+                <regexp name="positiveLength"/>
+            </regexp-list>
+        </property>
+        <property name="_mediafeature_max-width" description="">
+            <category-list>
+                <category value="mediafeature"/>
+            </category-list>
+            <regexp-list>
+                <regexp name="positiveLength"/>
+            </regexp-list>
+        </property>
         <!-- end manual properties -->
     </css-rules>
     <allowed-empty-tags>
diff --git a/src/test/java/org/owasp/validator/html/test/AntiSamyTest.java b/src/test/java/org/owasp/validator/html/test/AntiSamyTest.java
index 4699c24..0dcf7a2 100644
--- a/src/test/java/org/owasp/validator/html/test/AntiSamyTest.java
+++ b/src/test/java/org/owasp/validator/html/test/AntiSamyTest.java
@@ -34,6 +34,7 @@
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertThrows;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
@@ -67,6 +68,7 @@
 import org.owasp.validator.html.model.Property;
 import org.owasp.validator.html.model.Tag;
 import org.owasp.validator.html.scan.Constants;
+import org.w3c.css.sac.CSSParseException;
 
 /**
  * This class tests AntiSamy functionality and the basic policy file which should be immune to XSS
@@ -2755,4 +2757,129 @@ public void testGithubIssue546FaultyPercentagesGetFilteredByRegex() throws ScanE
     assertEquals(expectedCleanHtml, crDom.getCleanHTML());
     assertEquals(expectedCleanHtml, crSax.getCleanHTML());
   }
+
+  @Test
+  public void testGithubIssue552() throws ScanException, PolicyException {
+    Pattern positiveLength = Pattern.compile("((\\+)?0|(\\+)?([0-9]+(\\.[0-9]+)?([eE][+-]?[0-9]+)?)(rem|vw|vh|em|ex|px|in|cm|mm|pt|pc))");
+    Pattern integer = Pattern.compile("([-+])?[0-9]+");
+    Property mediaType = new Property("_mediatype",
+                                      Collections.emptyList(),
+                                      Arrays.asList("", "all", "print", "screen"),
+                                      Collections.emptyList(),
+                                      "",
+                                      "remove");
+    Property minWidth = new Property("_mediafeature_min-width",
+                                     Collections.singletonList(positiveLength),
+                                     Collections.emptyList(),
+                                     Collections.emptyList(),
+                                     "",
+                                     "remove");
+    Property maxWidth = new Property("_mediafeature_max-width",
+                                     Collections.singletonList(positiveLength),
+                                     Collections.emptyList(),
+                                     Collections.emptyList(),
+                                     "",
+                                     "remove");
+    Property color = new Property("_mediafeature_color",
+                                  Collections.singletonList(integer),
+                                  Collections.singletonList(""),
+                                  Collections.emptyList(),
+                                  "",
+                                  "remove");
+    Property orientation = new Property("_mediafeature_orientation",
+                                        Collections.emptyList(),
+                                        Arrays.asList("portrait", "landscape"),
+                                        Collections.emptyList(),
+                                        "",
+                                        "remove");
+    Property grid = new Property("_mediafeature_grid",
+                                 Collections.emptyList(),
+                                 Arrays.asList("", "-1", "-0", "0", "1"),
+                                 Collections.emptyList(),
+                                 "",
+                                 "remove");
+    Property monochrome = new Property("_mediafeature_monochrome",
+                                       Collections.singletonList(integer),
+                                       Collections.singletonList(""),
+                                       Collections.emptyList(),
+                                       "",
+                                       "remove");
+
+    checkStyleTag("@media screen {}",
+                  "@media screen {\n}\n",
+                  policy.addCssProperty(mediaType));
+
+    checkStyleTag("@media screen,print {}",
+                  "@media screen, print {\n}\n",
+                  policy.addCssProperty(mediaType));
+
+    checkStyleTag("@media only screen and (max-width: 639px) and (min-width: 300px) {}",
+                  "@media only screen and (max-width: 639.0px) and (min-width: 300.0px) {\n}\n",
+                  policy.addCssProperty(mediaType).addCssProperty(minWidth).addCssProperty(maxWidth));
+
+    checkStyleTag("@media not screen, screen and (color), print and (orientation: portrait) {}",
+                  "@media not screen, screen and (color), print and (orientation: portrait) {\n}\n",
+                  policy.addCssProperty(mediaType).addCssProperty(color).addCssProperty(orientation));
+
+    checkStyleTag("@media not screen, print and (orientation: doesNotExist), all {}",
+                  "@media not screen, all {\n}\n",
+                  policy.addCssProperty(mediaType).addCssProperty(orientation));
+
+    checkStyleTag("@media (min-width: 500.0px) {}",
+                  "@media (min-width: 500.0px) {\n}\n",
+                  policy.addCssProperty(mediaType).addCssProperty(minWidth));
+
+    checkStyleTag("@media (grid) {}",
+                  "@media (grid) {\n}\n",
+                  policy.addCssProperty(mediaType).addCssProperty(grid));
+
+    checkStyleTag("@media (monochrome) {}",
+                  "@media (monochrome) {\n}\n",
+                  policy.addCssProperty(mediaType).addCssProperty(monochrome));
+
+    checkStyleTag("@media (monochrome: 2) {}",
+                  "@media (monochrome: 2) {\n}\n",
+                  policy.addCssProperty(mediaType).addCssProperty(monochrome));
+
+    checkStyleTag("@media screen and (max-width: 639px) or only print {}",
+                  "@media screen and (max-width: 639.0px), only print {\n}\n",
+                  policy.addCssProperty(mediaType).addCssProperty(maxWidth));
+
+    checkStyleTag("@media print or (max-width: 639px) or only print {}",
+                  "@media print, (max-width: 639.0px), only print {\n}\n",
+                  policy.addCssProperty(mediaType).addCssProperty(maxWidth));
+
+    checkStyleTag("@media print or not (max-width: 639px), not print {}",
+                  "@media print, not (max-width: 639.0px), not print {\n}\n",
+                  policy.addCssProperty(mediaType).addCssProperty(maxWidth));
+
+    checkStyleTag("@media only print or not (max-width: 639px) and (min-width: 500px), not print {}",
+                  "@media only print, not (max-width: 639.0px) and (min-width: 500.0px), not print {\n}\n",
+                  policy.addCssProperty(mediaType).addCssProperty(maxWidth).addCssProperty(minWidth));
+
+    checkStyleTag("@media only print or not (max-width: 639px) and (min-width: 500px), not screen {}",
+                  "@media only print, not screen {\n}\n",
+                  policy.addCssProperty(mediaType).addCssProperty(maxWidth));
+
+    checkStyleTag("@media screen {*{color: red;notAllowed: nope}}",
+                  "@media screen {\n* {\n\tcolor: red;\n}\n}\n",
+                  policy.addCssProperty(mediaType));
+
+    assertThrows(CSSParseException.class, () -> checkStyleTag("@media notValid screen {}", "", policy));
+    assertThrows(CSSParseException.class, () -> checkStyleTag("@media doesNotExist {}", "", policy));
+  }
+
+  private void checkStyleTag(String input, String expected, Policy policy) throws ScanException, PolicyException {
+    //Given
+    String taintedHtml = "<style>" + input + "</style>";
+    String expectedCleanHtml = "<style>" + expected + "</style>";
+
+    //When
+    CleanResults crDom = as.scan(taintedHtml, policy, AntiSamy.DOM);
+    CleanResults crSax = as.scan(taintedHtml, policy, AntiSamy.SAX);
+
+    //Then
+    assertEquals(expectedCleanHtml, crDom.getCleanHTML());
+    assertEquals(expectedCleanHtml, crSax.getCleanHTML());
+  }
 }