diff --git a/www/addons/remotestyles/main.js b/www/addons/remotestyles/main.js
index 410e81d5ac3..794e967e55d 100644
--- a/www/addons/remotestyles/main.js
+++ b/www/addons/remotestyles/main.js
@@ -16,18 +16,35 @@ angular.module('mm.addons.remotestyles', [])
 
 .constant('mmaRemoteStylesComponent', 'mmaRemoteStyles')
 
+.config(function($mmInitDelegateProvider, mmInitDelegateMaxAddonPriority) {
+    // Addons shouldn't use a priority higher than mmInitDelegateMaxAddonPriority, but this is a special case
+    // because it needs to be done before the mmLogin process.
+    $mmInitDelegateProvider.registerProcess('mmaRemoteStylesCurrent',
+                '$mmaRemoteStyles._preloadCurrentSite', mmInitDelegateMaxAddonPriority + 250, true);
+    $mmInitDelegateProvider.registerProcess('mmaRemoteStylesPreload', '$mmaRemoteStyles._preloadSites');
+})
+
 .run(function($mmEvents, mmCoreEventLogin, mmCoreEventLogout, mmCoreEventSiteAdded, mmCoreEventSiteUpdated, $mmaRemoteStyles,
-            $mmSite) {
+            $mmSite, mmCoreEventSiteDeleted) {
 
-    $mmEvents.on(mmCoreEventSiteAdded, $mmaRemoteStyles.load);
-    $mmEvents.on(mmCoreEventSiteUpdated, function(siteid) {
+    $mmEvents.on(mmCoreEventSiteAdded, function(siteId) {
+        $mmaRemoteStyles.addSite(siteId);
+    });
+    $mmEvents.on(mmCoreEventSiteUpdated, function(siteId) {
         // Load only if current site was updated.
-        if (siteid === $mmSite.getId()) {
-            $mmaRemoteStyles.load();
+        if (siteId === $mmSite.getId()) {
+            $mmaRemoteStyles.load(siteId);
         }
     });
-    $mmEvents.on(mmCoreEventLogin, $mmaRemoteStyles.load);
 
-    // Remove added styles on logout.
+    // Enable styles of current site on login.
+    $mmEvents.on(mmCoreEventLogin, $mmaRemoteStyles.enable);
+
+    // Disable added styles on logout.
     $mmEvents.on(mmCoreEventLogout, $mmaRemoteStyles.clear);
+
+    // Remove site styles on logout.
+    $mmEvents.on(mmCoreEventSiteDeleted, function(site) {
+        $mmaRemoteStyles.removeSite(site.id);
+    });
 });
diff --git a/www/addons/remotestyles/services/remotestyles.js b/www/addons/remotestyles/services/remotestyles.js
index c2191652071..4659b47de82 100644
--- a/www/addons/remotestyles/services/remotestyles.js
+++ b/www/addons/remotestyles/services/remotestyles.js
@@ -22,12 +22,36 @@ angular.module('mm.addons.remotestyles')
  * @name $mmaRemoteStyles
  */
 .factory('$mmaRemoteStyles', function($log, $q, $mmSite, $mmSitesManager, $mmFilepool, $http, $mmFS, mmaRemoteStylesComponent,
-            mmCoreNotDownloaded) {
+            mmCoreNotDownloaded, $mmUtil, md5) {
 
     $log = $log.getInstance('$mmaRemoteStyles');
 
     var self = {},
-        remoteStylesEl = angular.element(document.querySelector('#mobilecssurl'));
+        remoteStylesEls = {};
+
+    /**
+     * Add a style element for a site and load the styles for that element. The style will be disabled.
+     *
+     * @module mm.addons.remotestyles
+     * @ngdoc method
+     * @name $mmaRemoteStyles#addSite
+     * @param  {String} siteId Site ID.
+     * @return {Promise}       Promise resolved when added and loaded.
+     */
+    self.addSite = function(siteId) {
+        if (!siteId || remoteStylesEls[siteId]) {
+            return $q.when();
+        }
+
+        var el = angular.element('<style id="mobilecssurl-' + siteId + '" disabled="disabled"></style>');
+        angular.element(document.head).append(el);
+        remoteStylesEls[siteId] = {
+            element: el,
+            hash: ''
+        };
+
+        return self.load(siteId, true);
+    };
 
     /**
      * Clear remote styles added to the DOM.
@@ -37,7 +61,47 @@ angular.module('mm.addons.remotestyles')
      * @name $mmaRemoteStyles#clear
      */
     self.clear = function() {
-        remoteStylesEl.html('');
+        // Disable all the styles.
+        angular.element(document.querySelectorAll('style[id*=mobilecssurl]')).attr('disabled', true);
+    };
+
+    /**
+     * Downloads a CSS file and remove old files if needed.
+     *
+     * @param  {String} siteId Site ID.
+     * @param  {String} url    File URL.
+     * @return {Promise}       Promise resolved when the file is downloaded.
+     */
+    function downloadFileAndRemoveOld(siteId, url) {
+        return $mmFilepool.getFileStateByUrl(siteId, url).then(function(state) {
+            return state !== mmCoreNotDownloaded;
+        }).catch(function() {
+            return true; // An error occurred while getting state (shouldn't happen). Don't delete downloaded file.
+        }).then(function(isDownloaded) {
+            if (!isDownloaded) {
+                // File not downloaded, URL has changed or first time. Delete downloaded CSS files.
+                return $mmFilepool.removeFilesByComponent(siteId, mmaRemoteStylesComponent, 1);
+            }
+        }).then(function() {
+            return $mmFilepool.downloadUrl(siteId, url, false, mmaRemoteStylesComponent, 1);
+        });
+    }
+
+    /**
+     * Enable the styles of a certain site.
+     *
+     * @module mm.addons.remotestyles
+     * @ngdoc method
+     * @name $mmaRemoteStyles#addSite
+     * @param  {String} [siteId] Site ID. If not defined, current site.
+     * @return {Void}
+     */
+    self.enable = function(siteId) {
+        siteId = siteId || $mmSite.getId();
+
+        if (remoteStylesEls[siteId]) {
+            remoteStylesEls[siteId].element.attr('disabled', false);
+        }
     };
 
     /**
@@ -46,39 +110,25 @@ angular.module('mm.addons.remotestyles')
      * @module mm.addons.remotestyles
      * @ngdoc method
      * @name $mmaRemoteStyles#get
-     * @param {String} siteid Site ID.
-     * @return {Promise}      Promise resolved with the styles.
+     * @param {String} [siteId] Site ID. If not defined, current site.
+     * @return {Promise}        Promise resolved with the styles and the URL of the loaded CSS file (local if downloaded).
      */
-    self.get = function(siteid) {
-        var promise;
+    self.get = function(siteId) {
+        var fileUrl;
 
-        siteid = siteid || $mmSite.getId();
-        if (!siteid) {
+        siteId = siteId || $mmSite.getId();
+        if (!siteId) {
             return $q.reject();
         }
 
-        // Downloads a CSS file and remove old files if needed.
-        function downloadFileAndRemoveOld(url) {
-            return $mmFilepool.getFileStateByUrl(siteid, url).then(function(state) {
-                return state !== mmCoreNotDownloaded;
-            }).catch(function() {
-                return true; // An error occurred while getting state (shouldn't happen). Don't delete downloaded file.
-            }).then(function(isDownloaded) {
-                if (!isDownloaded) {
-                    // File not downloaded, URL has changed or first time. Delete downloaded CSS files.
-                    return $mmFilepool.removeFilesByComponent(siteid, mmaRemoteStylesComponent, 1);
-                }
-            }).then(function() {
-                return $mmFilepool.downloadUrl(siteid, url, false, mmaRemoteStylesComponent, 1);
-            });
-        }
-
-        return $mmSitesManager.getSite(siteid).then(function(site) {
+        return $mmSitesManager.getSite(siteId).then(function(site) {
             var infos = site.getInfo();
             if (infos && infos.mobilecssurl) {
+                fileUrl = infos.mobilecssurl;
+
                 if ($mmFS.isAvailable()) {
                     // The file system is available. Download the file and remove old CSS files if needed.
-                    return downloadFileAndRemoveOld(infos.mobilecssurl);
+                    return downloadFileAndRemoveOld(siteId, infos.mobilecssurl);
                 } else {
                     // We return the online URL. We're probably on browser.
                     return infos.mobilecssurl;
@@ -86,7 +136,7 @@ angular.module('mm.addons.remotestyles')
             } else {
                 if (infos.mobilecssurl === '') {
                     // CSS URL is empty. Delete downloaded files (if any).
-                    $mmFilepool.removeFilesByComponent(siteid, mmaRemoteStylesComponent, 1)
+                    $mmFilepool.removeFilesByComponent(siteId, mmaRemoteStylesComponent, 1);
                 }
                 return $q.reject();
             }
@@ -95,7 +145,7 @@ angular.module('mm.addons.remotestyles')
             return $http.get(url);
         }).then(function(response) {
             if (typeof response.data == 'string') {
-                return response.data;
+                return {file: fileUrl, styles: response.data};
             } else {
                 return $q.reject();
             }
@@ -103,22 +153,144 @@ angular.module('mm.addons.remotestyles')
     };
 
     /**
-     * Load styles for current site.
+     * Load styles for a certain site.
      *
      * @module mm.addons.remotestyles
      * @ngdoc method
      * @name $mmaRemoteStyles#load
+     * @param  {String} [siteId]  Site ID. If not defined, current site.
+     * @param  {Boolean} disabled True if loaded styles should be disabled, false if they should be enabled.
+     * @return {Promise}          Promise resolved when styles are loaded.
      */
-    self.load = function() {
-        var siteid = $mmSite.getId();
-        if (siteid) {
-            self.get(siteid).then(function(styles) {
-                if (siteid === $mmSite.getId()) { // Make sure it hasn't logout while retrieving styles.
-                    remoteStylesEl.html(styles);
+    self.load = function(siteId, disabled) {
+        siteId = siteId || $mmSite.getId();
+        disabled = !!disabled;
+
+        $log.debug('Load site: ', siteId, disabled);
+        if (siteId && remoteStylesEls[siteId]) {
+            // Enable or disable the styles.
+            remoteStylesEls[siteId].element.attr('disabled', disabled);
+
+            return self.get(siteId).then(function(data) {
+                var hash = md5.createHash(data.styles);
+
+                // Update the styles only if they have changed.
+                if (remoteStylesEls[siteId].hash !== hash) {
+                    remoteStylesEls[siteId].element.html(data.styles);
+                    remoteStylesEls[siteId].hash = hash;
+
+                    // New styles will be applied even if the style is disabled. We'll disable it again if needed.
+                    if (disabled && remoteStylesEls[siteId].element.attr('disabled') == 'disabled') {
+                        remoteStylesEls[siteId].element.attr('disabled', true);
+                    }
                 }
+
+                // Styles have been loaded, now treat the CSS.
+                treatCSSCode(siteId, data.file, data.styles);
             });
         }
+
+        return $q.reject();
     };
 
+    /**
+     * Preload the styles of the current site (stored in DB). Please do not use.
+     *
+     * @module mm.addons.remotestyles
+     * @ngdoc method
+     * @name $mmaRemoteStyles#_preloadCurrentSite
+     * @return {Promise} Promise resolved when loaded.
+     * @protected
+     */
+    self._preloadCurrentSite = function() {
+        return $mmSitesManager.getStoredCurrentSiteId().then(function(siteId) {
+            return self.addSite(siteId);
+        });
+    };
+
+    /**
+     * Preload the styles of all the stored sites. Please do not use.
+     *
+     * @module mm.addons.remotestyles
+     * @ngdoc method
+     * @name $mmaRemoteStyles#_preloadSites
+     * @return {Promise} Promise resolved when loaded.
+     * @protected
+     */
+    self._preloadSites = function() {
+        return $mmSitesManager.getSitesIds().then(function(ids) {
+            var promises = [];
+            angular.forEach(ids, function(siteId) {
+                promises.push(self.addSite(siteId));
+            });
+            return $q.all(promises);
+        });
+    };
+
+    /**
+     * Remove the styles of a certain site.
+     *
+     * @module mm.addons.remotestyles
+     * @ngdoc method
+     * @name $mmaRemoteStyles#removeSite
+     * @param  {String} siteId Site ID.
+     * @return {Void}
+     */
+    self.removeSite = function(siteId) {
+        if (siteId && remoteStylesEls[siteId]) {
+            remoteStylesEls[siteId].element.remove();
+            delete remoteStylesEls[siteId];
+        }
+    };
+
+    /**
+     * Search for files in a CSS code and try to download them. Once downloaded, replace their URLs
+     * and store the result in the CSS file.
+     *
+     * @param  {String} siteId  Site ID.
+     * @param  {String} fileUrl CSS file URL.
+     * @param  {String} cssCode CSS code.
+     * @return {Promise}        Promise resolved with the CSS code.
+     */
+    function treatCSSCode(siteId, fileUrl, cssCode) {
+        if (!$mmFS.isAvailable()) {
+            return $q.reject();
+        }
+
+        var urls = $mmUtil.extractUrlsFromCSS(cssCode),
+            promises = [],
+            filePath,
+            updated = false;
+
+        // Get the path of the CSS file.
+        promises.push($mmFilepool.getFilePathByUrl(siteId, fileUrl).then(function(path) {
+            filePath = path;
+        }));
+
+        angular.forEach(urls, function(url) {
+            // Download the file only if it's an online URL.
+            if (url.indexOf('http') == 0) {
+                promises.push($mmFilepool.downloadUrl(siteId, url, false, mmaRemoteStylesComponent, 2).then(function(fileUrl) {
+                    if (fileUrl != url) {
+                        cssCode = cssCode.replace(new RegExp(url, 'g'), fileUrl);
+                        updated = true;
+                    }
+                }).catch(function(error) {
+                    // It shouldn't happen. Ignore errors.
+                    $log.warn('MMRMSTYLES Error treating file ', url, error);
+                }));
+            }
+        });
+
+        return $q.all(promises).then(function() {
+            // All files downloaded. Store the result if it has changed.
+            if (updated) {
+                return $mmFS.writeFile(filePath, cssCode);
+            }
+        }).then(function() {
+            return cssCode;
+        });
+    }
+
     return self;
 });
diff --git a/www/core/lib/sitesmanager.js b/www/core/lib/sitesmanager.js
index 47cda2cadd8..db5a882f399 100644
--- a/www/core/lib/sitesmanager.js
+++ b/www/core/lib/sitesmanager.js
@@ -222,7 +222,7 @@ angular.module('mm.core')
                     currentSite = candidateSite;
                     // Store session.
                     self.login(siteid);
-                    $mmEvents.trigger(mmCoreEventSiteAdded);
+                    $mmEvents.trigger(mmCoreEventSiteAdded, siteid);
                 } else {
                     return $translate(validation.error, validation.params).then(function(error) {
                         return $q.reject(error);
@@ -723,6 +723,20 @@ angular.module('mm.core')
         });
     };
 
+    /**
+     * Get the site ID stored in DB ad current site.
+     *
+     * @module mm.core
+     * @ngdoc method
+     * @name $mmSitesManager#getStoredCurrentSiteId
+     * @return {Promise} Promise resolved with the site ID.
+     */
+    self.getStoredCurrentSiteId = function() {
+        return $mmApp.getDB().get(mmCoreCurrentSiteStore, 1).then(function(current_site) {
+            return current_site.siteid;
+        });
+    };
+
     return self;
 
 });
diff --git a/www/core/lib/util.js b/www/core/lib/util.js
index b2f15069853..6d895b017be 100644
--- a/www/core/lib/util.js
+++ b/www/core/lib/util.js
@@ -1039,6 +1039,31 @@ angular.module('mm.core')
             return true;
         };
 
+        /**
+         * Search all the URLs in a CSS file content.
+         *
+         * @module mm.core
+         * @ngdoc method
+         * @name $mmUtil#extractUrlsFromCSS
+         * @param  {String} code CSS code.
+         * @return {String[]}    List of URLs.
+         */
+        self.extractUrlsFromCSS = function(code) {
+            // First of all, search all the url(...) occurrences that don't include "data:".
+            var urls = [],
+                matches = code.match(/url\(\s*["']?(?!data:)([^)]+)\)/igm);
+
+            // Extract the URL form each match.
+            angular.forEach(matches, function(match) {
+                var submatches = match.match(/url\(\s*['"]?([^'"]*)['"]?\s*\)/im);
+                if (submatches && submatches[1]) {
+                    urls.push(submatches[1]);
+                }
+            });
+
+            return urls;
+        };
+
         return self;
     };
 });
diff --git a/www/index.html b/www/index.html
index f8b1ceb0338..5a9b67efd4b 100644
--- a/www/index.html
+++ b/www/index.html
@@ -17,7 +17,7 @@
     <script src="lib/moment/min/moment-with-locales.js"></script>
     <script src="lib/jszip/dist/jszip.js"></script>
     <script src="build/mm.bundle.js"></script>
-    <style id="mobilecssurl"></style>
+    <style></style> <!-- Empty style to make easier to test styles using Inspector. -->
   </head>
   <body ng-app="mm">
     <ion-nav-view></ion-nav-view>