diff --git a/src/ZenThemesImporter.mjs b/src/ZenThemesImporter.mjs
new file mode 100644
index 0000000..b23c1e6
--- /dev/null
+++ b/src/ZenThemesImporter.mjs
@@ -0,0 +1,133 @@
+
+const kZenStylesheetThemeHeader = `
+/* Zen Themes - Generated by ZenThemeImporter.
+  * DO NOT EDIT THIS FILE DIRECTLY!
+  * Your changes will be overwritten.
+  * Instead, go to the preferences and edit the themes there.
+  */`;
+const kenStylesheetFooter = `
+/* End of Zen Themes */
+`;
+var gZenStylesheetManager = {
+  async writeStylesheet(path, themes) {
+    let content = kZenStylesheetThemeHeader;
+    for (let theme of themes) {
+      content += this.getThemeCSS(theme);
+    }
+    content += kenStylesheetFooter;
+    let buffer = new TextEncoder().encode(content);
+    await IOUtils.write(path, buffer);
+  },
+
+  getThemeCSS(theme) {
+    let css = "\n";
+    if (theme._readmeURL) {
+      css += `/* Name: ${theme.name} */\n`;
+      css += `/* Description: ${theme.description} */\n`;
+      css += `/* Author: @${theme.author} */\n`;
+      css += `/* Readme: ${theme.readme} */\n`;
+    }
+    css += `@import url("${theme._chromeURL}");\n`;
+    return css;
+  }
+};
+
+var gZenThemeImporter = new class {
+  constructor() {
+    console.info("ZenThemeImporter: Initiating Zen theme importer");
+    try {
+      this.insertStylesheet();
+      console.info("ZenThemeImporter: Zen theme imported");
+    } catch (e) {
+      console.error("ZenThemeImporter: Error importing Zen theme: ", e);
+    }
+    Services.prefs.addObserver("zen.themes.updated-value-observer", this.updateStylesheet.bind(this), false);
+  }
+
+  get sss() {
+    if (!this._sss) {
+      this._sss = Cc["@mozilla.org/content/style-sheet-service;1"].getService(Ci.nsIStyleSheetService);
+    }
+    return this._sss;
+  }
+
+  get styleSheetPath() {
+    return PathUtils.join(
+      PathUtils.profileDir,
+      "chrome",
+      "zen-themes.css"
+    );
+  }
+
+  get themesRootPath() {
+    return PathUtils.join(
+      PathUtils.profileDir,
+      "chrome",
+      "zen-themes"
+    );
+  }
+
+  get themesDataFile() {
+    return PathUtils.join(
+      PathUtils.profileDir,
+      "zen-themes.json"
+    );
+  }
+
+  getThemeFolder(theme) {
+    return PathUtils.join(this.themesRootPath, theme.id);
+  }
+
+  async getThemes() {
+    if (!this._themes) {
+      if (!(await IOUtils.exists(this.themesDataFile))) {
+        await IOUtils.writeJSON(this.themesDataFile, {});
+      }
+      this._themes = await IOUtils.readJSON(this.themesDataFile);
+    }
+    return this._themes;
+  }
+
+  rebuildThemeStylesheet() {
+    this._themes = null;
+    this.updateStylesheet();
+  }
+
+  get styleSheetURI() {
+    if (!this._styleSheetURI) {
+      this._styleSheetURI = Services.io.newFileURI(new FileUtils.File(this.styleSheetPath));
+    }
+    return this._styleSheetURI;
+  }
+
+  getStylesheetURIForTheme(theme) {
+    return Services.io.newFileURI(new FileUtils.File(PathUtils.join(this.getThemeFolder(theme), "chrome.css")));
+  }
+
+  insertStylesheet() {
+    if (IOUtils.exists(this.styleSheetPath)) {
+      this.sss.loadAndRegisterSheet(this.styleSheetURI, this.sss.USER_SHEET);
+    }
+  }
+
+  removeStylesheet() {
+    this.sss.unregisterSheet(this.styleSheetURI, this.sss.USER_SHEET);
+  }
+
+  async updateStylesheet() {
+    this.removeStylesheet();
+    await this.writeStylesheet();
+    this.insertStylesheet();
+  }
+
+  async writeStylesheet() {
+    const themes = []
+    this._themes = null;
+    for (let theme of Object.values(await this.getThemes())) {
+      theme._chromeURL = this.getStylesheetURIForTheme(theme).spec;
+      console.info("ZenThemeImporter: Writing theme: ", theme._chromeURL);
+      themes.push(theme);
+    }
+    gZenStylesheetManager.writeStylesheet(this.styleSheetPath, themes);
+  }
+};
diff --git a/src/actors/ZenThemeMarketplaceChild.sys.mjs b/src/actors/ZenThemeMarketplaceChild.sys.mjs
index edb96ad..f4c48f5 100644
--- a/src/actors/ZenThemeMarketplaceChild.sys.mjs
+++ b/src/actors/ZenThemeMarketplaceChild.sys.mjs
@@ -19,17 +19,59 @@ export class ZenThemeMarketplaceChild extends JSWindowActorChild {
     }, 0);
   }
 
+  get actionButton() {
+    return this.contentWindow.document.getElementById("install-theme");
+  }
+
+  get actionButtonUnnstall() {
+    return this.contentWindow.document.getElementById("install-theme-uninstall");
+  }
+
+  async receiveMessage(message) {
+    switch (message.name) {
+      case "ZenThemeMarketplace:ThemeChanged": {
+        const themeId = message.data.themeId;
+        const actionButton = this.actionButton;
+        const actionButtonInstalled = this.actionButtonUnnstall;
+        if (actionButton && actionButtonInstalled) {
+          actionButton.disabled = false;
+          actionButtonInstalled.disabled = false;
+          if (await this.isThemeInstalled(themeId)) {
+            actionButton.classList.add("hidden");
+            actionButtonInstalled.classList.remove("hidden");
+          } else {
+            actionButton.classList.remove("hidden");
+            actionButtonInstalled.classList.add("hidden");
+          }
+        }
+        break;
+      }
+    }
+  }
+
   async addIntallButtons() {
-    
-    const actionButton = this.contentWindow.document.getElementById("install-theme");
+    const actionButton = this.actionButton;
+    const actionButtonUnnstall = this.actionButtonUnnstall;
     const errorMessage = this.contentWindow.document.getElementById("install-theme-error");
-    if (actionButton) {
-      console.info("ZenThemeMarketplaceChild: Initiating theme marketplace");
+    if (!actionButton || !actionButtonUnnstall) {
+      return;
     }
 
     errorMessage.classList.add("hidden");
-    actionButton.classList.remove("hidden");
+    
+    const themeId = actionButton.getAttribute("zen-theme-id");
+    if (await this.isThemeInstalled(themeId)) {
+      actionButtonUnnstall.classList.remove("hidden");
+    } else {
+      actionButton.classList.remove("hidden");
+    }
+
     actionButton.addEventListener("click", this.installTheme.bind(this));
+    actionButtonUnnstall.addEventListener("click", this.uninstallTheme.bind(this));
+  }
+
+  async isThemeInstalled(themeId) {
+    return await this.sendQuery("ZenThemeMarketplace:IsThemeInstalled", { themeId });
   }
 
   addTheme(theme) {
@@ -54,8 +96,17 @@ export class ZenThemeMarketplaceChild extends JSWindowActorChild {
     return null; 
   }
 
+  async uninstallTheme(event) {
+    const button = event.target;
+    button.disabled = true;
+    const themeId = button.getAttribute("zen-theme-id");
+    console.info("ZTM: Uninstalling theme with id: ", themeId);
+    this.sendAsyncMessage("ZenThemeMarketplace:UninstallTheme", { themeId });
+  }
+
   async installTheme(event) {
     const button = event.target;
+    button.disabled = true;
     const themeId = button.getAttribute("zen-theme-id");
     console.info("ZTM: Installing theme with id: ", themeId);
 
diff --git a/src/actors/ZenThemeMarketplaceParent.sys.mjs b/src/actors/ZenThemeMarketplaceParent.sys.mjs
index d9421bd..1958c0b 100644
--- a/src/actors/ZenThemeMarketplaceParent.sys.mjs
+++ b/src/actors/ZenThemeMarketplaceParent.sys.mjs
@@ -12,11 +12,31 @@ export class ZenThemeMarketplaceParent extends JSWindowActorParent {
         const themes = await this.getThemes();
         themes[theme.id] = theme;
         this.updateThemes(themes);
+        this.updateChildProcesses(theme.id);
         break;
       }
+      case "ZenThemeMarketplace:UninstallTheme": {
+        console.info("ZenThemeMarketplaceParent: Uninstalling theme");
+        const themeId = message.data.themeId;
+        const themes = await this.getThemes();
+        delete themes[themeId];
+        this.removeTheme(themeId);
+        this.updateThemes(themes);
+        this.updateChildProcesses(themeId);
+        break;
+      }
+      case "ZenThemeMarketplace:IsThemeInstalled": {
+        const themeId = message.data.themeId;
+        const themes = await this.getThemes();
+        return themes[themeId] ? true : false;
+      }
     }
   }
 
+  async updateChildProcesses(themeId) {
+    this.sendAsyncMessage("ZenThemeMarketplace:ThemeChanged", { themeId });
+  }
+
   async getThemes() {
     if (!this._themes) {
       if (!(await IOUtils.exists(this.themesDataFile))) {
@@ -68,14 +88,19 @@ export class ZenThemeMarketplaceParent extends JSWindowActorParent {
     );
   }
 
+  triggerThemeUpdate() {
+    const pref = "zen.themes.updated-value-observer";
+    Services.prefs.setBoolPref(pref, !Services.prefs.getBoolPref(pref));
+  }
+
   async installTheme(theme) {
     await this.downloadThemeFileContents(theme);
-    this.sendAsyncMessage("ZenThemeMarketplace:ThemeInstalled", { theme });
   }
 
   async checkForThemeChanges() {
     const themes = await this.getThemes();
     const themeIds = Object.keys(themes);
+    let changed = false;
     for (const themeId of themeIds) {
       const theme = themes[themeId];
       if (!theme) {
@@ -83,9 +108,19 @@ export class ZenThemeMarketplaceParent extends JSWindowActorParent {
       }
       const themePath = PathUtils.join(this.themesRootPath, themeId);
       if (!(await IOUtils.exists(themePath))) {
-        console.info("ZenThemeMarketplaceParent: Installing theme ", themeId);
-        this.installTheme(theme);
+        await this.installTheme(theme);
+        changed = true;
       }
     }
+    if (changed) {
+      this.triggerThemeUpdate();
+    }
+  }
+
+  async removeTheme(themeId) {
+    const themePath = PathUtils.join(this.themesRootPath, themeId);
+    console.info("ZenThemeMarketplaceParent: Removing theme ", themePath);
+    await IOUtils.remove(themePath, { recursive: true, ignoreAbsent: true });
+    this.triggerThemeUpdate();
   }
 };
\ No newline at end of file