diff --git a/platform/mv3/extension/js/scripting-manager.js b/platform/mv3/extension/js/scripting-manager.js
index 1d9d42876..f1f949016 100644
--- a/platform/mv3/extension/js/scripting-manager.js
+++ b/platform/mv3/extension/js/scripting-manager.js
@@ -79,7 +79,12 @@ const arrayEq = (a = [], b = [], sort = true) => {
 
 const normalizeRegisteredContentScripts = registered => {
     for ( const entry of registered ) {
-        const { js } = entry;
+        const { css = [], js = [] } = entry;
+        for ( let i = 0; i < css.length; i++ ) {
+            const path = css[i];
+            if ( path.startsWith('/') ) { continue; }
+            css[i] = `/${path}`;
+        }
         for ( let i = 0; i < js.length; i++ ) {
             const path = js[i];
             if ( path.startsWith('/') ) { continue; }
@@ -91,6 +96,78 @@ const normalizeRegisteredContentScripts = registered => {
 
 /******************************************************************************/
 
+function registerHighGeneric(context, genericDetails) {
+    const { before, filteringModeDetails, rulesetsDetails } = context;
+
+    const excludeHostnames = [];
+    const css = [];
+    for ( const details of rulesetsDetails ) {
+        const hostnames = genericDetails.get(details.id);
+        if ( hostnames !== undefined ) {
+            excludeHostnames.push(...hostnames);
+        }
+        const count = details.css?.generichigh || 0;
+        if ( count === 0 ) { continue; }
+        css.push(`/rulesets/scripting/generichigh/${details.id}.css`);
+    }
+
+    if ( css.length === 0 ) { return; }
+
+    const { none, basic, optimal, complete } = filteringModeDetails;
+    const matches = [];
+    const excludeMatches = [];
+    if ( complete.has('all-urls') ) {
+        excludeMatches.push(...ut.matchesFromHostnames(none));
+        excludeMatches.push(...ut.matchesFromHostnames(basic));
+        excludeMatches.push(...ut.matchesFromHostnames(optimal));
+        excludeMatches.push(...ut.matchesFromHostnames(excludeHostnames));
+        matches.push('<all_urls>');
+    } else {
+        matches.push(
+            ...ut.matchesFromHostnames(
+                ut.subtractHostnameIters(
+                    Array.from(complete),
+                    excludeHostnames
+                )
+            )
+        );
+    }
+
+    if ( matches.length === 0 ) { return; }
+
+    const registered = before.get('css-generichigh');
+    before.delete('css-generichigh'); // Important!
+
+    // https://github.com/w3c/webextensions/issues/414#issuecomment-1623992885
+    // Once supported, add:
+    // cssOrigin: 'USER',
+    const directive = {
+        id: 'css-generichigh',
+        css,
+        matches,
+        excludeMatches,
+        runAt: 'document_end',
+    };
+
+    // register
+    if ( registered === undefined ) {
+        context.toAdd.push(directive);
+        return;
+    }
+
+    // update
+    if (
+        arrayEq(registered.css, css, false) === false ||
+        arrayEq(registered.matches, matches) === false ||
+        arrayEq(registered.excludeMatches, excludeMatches) === false
+    ) {
+        context.toRemove.push('css-generichigh');
+        context.toAdd.push(directive);
+    }
+}
+
+/******************************************************************************/
+
 function registerGeneric(context, genericDetails) {
     const { before, filteringModeDetails, rulesetsDetails } = context;
 
@@ -459,6 +536,7 @@ async function registerInjectables(origins) {
     registerScriptlet(context, scriptletDetails);
     registerSpecific(context);
     registerGeneric(context, genericDetails);
+    registerHighGeneric(context, genericDetails);
 
     toRemove.push(...Array.from(before.keys()));
 
diff --git a/platform/mv3/make-rulesets.js b/platform/mv3/make-rulesets.js
index 611d80245..4c1f27959 100644
--- a/platform/mv3/make-rulesets.js
+++ b/platform/mv3/make-rulesets.js
@@ -382,7 +382,8 @@ function loadAllSourceScriptlets() {
             const originalScriptletMap = new Map();
             for ( const details of results ) {
                 originalScriptletMap.set(
-                    details.file.replace('.template.js', ''),
+                    details.file.replace('.template.js', '')
+                                .replace('.template.css', ''),
                     details.text
                 );
             }
@@ -395,7 +396,7 @@ function loadAllSourceScriptlets() {
 
 /******************************************************************************/
 
-async function processGenericCosmeticFilters(assetDetails, bucketsMap, exclusions) {
+async function processGenericCosmeticFilters(assetDetails, bucketsMap) {
     if ( bucketsMap === undefined ) { return 0; }
     if ( bucketsMap.size === 0 ) { return 0; }
     const bucketsList = Array.from(bucketsMap);
@@ -419,8 +420,6 @@ async function processGenericCosmeticFilters(assetDetails, bucketsMap, exclusion
         patchedScriptlet
     );
 
-    genericDetails.set(assetDetails.id, exclusions.sort());
-
     log(`CSS-generic: ${count} plain CSS selectors`);
 
     return count;
@@ -428,6 +427,33 @@ async function processGenericCosmeticFilters(assetDetails, bucketsMap, exclusion
 
 /******************************************************************************/
 
+async function processGenericHighCosmeticFilters(assetDetails, selectorSet) {
+    if ( selectorSet === undefined ) { return 0; }
+    if ( selectorSet.size === 0 ) { return 0; }
+    const selectorLists = Array.from(selectorSet).sort().join(',\n');
+    const originalScriptletMap = await loadAllSourceScriptlets();
+
+    let patchedScriptlet = originalScriptletMap.get('css-generichigh').replace(
+        '$rulesetId$',
+        assetDetails.id
+    );
+    patchedScriptlet = safeReplace(patchedScriptlet,
+        /\$selectorList\$/,
+        selectorLists
+    );
+
+    writeFile(
+        `${scriptletDir}/generichigh/${assetDetails.id}.css`,
+        patchedScriptlet
+    );
+
+    log(`CSS-generic-high: ${selectorSet.size} plain CSS selectors`);
+
+    return selectorSet.size;
+}
+
+/******************************************************************************/
+
 // This merges selectors which are used by the same hostnames
 
 function groupSelectorsByHostnames(mapin) {
@@ -887,10 +913,23 @@ async function rulesetFromURLs(assetDetails) {
         log(rejectedCosmetic.map(line => `\t${line}`).join('\n'), true);
     }
 
+    if (
+        Array.isArray(results.network.generichideExclusions) &&
+        results.network.generichideExclusions.length !== 0
+    ) {
+        genericDetails.set(
+            assetDetails.id,
+            results.network.generichideExclusions.filter(hn => hn.endsWith('.*') === false).sort()
+        );
+    }
+
     const genericCosmeticStats = await processGenericCosmeticFilters(
         assetDetails,
-        results.genericCosmetic,
-        results.network.generichideExclusions.filter(hn => hn.endsWith('.*') === false)
+        results.genericCosmetic
+    );
+    const genericHighCosmeticStats = await processGenericHighCosmeticFilters(
+        assetDetails,
+        results.genericHighCosmetic
     );
     const specificCosmeticStats = await processCosmeticFilters(
         assetDetails,
@@ -933,6 +972,7 @@ async function rulesetFromURLs(assetDetails) {
         },
         css: {
             generic: genericCosmeticStats,
+            generichigh: genericHighCosmeticStats,
             specific: specificCosmeticStats,
             declarative: declarativeStats,
             procedural: proceduralStats,
diff --git a/src/js/static-dnr-filtering.js b/src/js/static-dnr-filtering.js
index 99fa9241b..4177991b9 100644
--- a/src/js/static-dnr-filtering.js
+++ b/src/js/static-dnr-filtering.js
@@ -147,17 +147,23 @@ function addExtendedToDNR(context, parser) {
 
     // Generic cosmetic filtering
     if ( parser.hasOptions() === false ) {
-        if ( context.genericCosmeticFilters === undefined ) {
-            context.genericCosmeticFilters = new Map();
-        }
         const { compiled } = parser.result;
         if ( compiled === undefined ) { return; }
         if ( compiled.length <= 1 ) { return; }
         if ( compiled.charCodeAt(0) === 0x7B /* '{' */ ) { return; }
         const key = keyFromSelector(compiled);
-        if ( key === undefined ) { return; }
+        if ( key === undefined ) {
+            if ( context.genericHighCosmeticFilters === undefined ) {
+                context.genericHighCosmeticFilters = new Set();
+            }
+            context.genericHighCosmeticFilters.add(compiled);
+            return;
+        }
         const type = key.charCodeAt(0);
         const hash = hashFromStr(type, key.slice(1));
+        if ( context.genericCosmeticFilters === undefined ) {
+            context.genericCosmeticFilters = new Map();
+        }
         let bucket = context.genericCosmeticFilters.get(hash);
         if ( bucket === undefined ) {
             context.genericCosmeticFilters.set(hash, bucket = []);
@@ -291,6 +297,7 @@ async function dnrRulesetFromRawLists(lists, options = {}) {
     return {
         network: staticNetFilteringEngine.dnrFromCompiled('end', context),
         genericCosmetic: context.genericCosmeticFilters,
+        genericHighCosmetic: context.genericHighCosmeticFilters,
         specificCosmetic: context.specificCosmeticFilters,
         scriptlet: context.scriptletFilters,
     };