diff --git a/app/Bootstrap/ViewComposer.php b/app/Bootstrap/ViewComposer.php
index 14809fc..0c23e51 100644
--- a/app/Bootstrap/ViewComposer.php
+++ b/app/Bootstrap/ViewComposer.php
@@ -9,32 +9,41 @@ use Twig\TwigFunction;
 
 class ViewComposer
 {
+    /** @var Config Application config */
+    protected $config;
+
+    /** @var Twig Twig instance */
+    protected $twig;
+
+    /**
+     * Create a new ViewComposer object.
+     *
+     * @param \PHLAK\Config\Config $config
+     */
+    public function __construct(Config $config, Twig $twig)
+    {
+        $this->config = $config;
+        $this->twig = $twig;
+    }
+
     /**
      * Set up the Twig component.
      *
      * @return void
      */
-    public function __invoke(Config $config, Twig $twig): void
+    public function __invoke(): void
     {
-        $twig->getEnvironment()->getExtension(CoreExtension::class)->setDateFormat(
-            $config->get('date_format', 'Y-m-d H:i:s'), '%d days'
+        $this->twig->getEnvironment()->getExtension(CoreExtension::class)->setDateFormat(
+            $this->config->get('date_format', 'Y-m-d H:i:s'), '%d days'
         );
 
-        $twig->getEnvironment()->addFunction(
-            new TwigFunction('asset', function ($path) use ($config) {
-                return "/app/themes/{$config->get('theme', 'defualt')}/{$path}";
+        $this->twig->getEnvironment()->addFunction(
+            new TwigFunction('asset', function ($path) {
+                return "/app/themes/{$this->config->get('theme', 'defualt')}/{$path}";
             })
         );
 
-        $twig->getEnvironment()->addFunction(
-            new TwigFunction('icon', function ($file) use ($config) {
-                $extension = pathinfo($file, PATHINFO_EXTENSION);
-
-                return $config->get("icons.{$extension}", 'fa-file');
-            })
-        );
-
-        $twig->getEnvironment()->addFunction(
+        $this->twig->getEnvironment()->addFunction(
             new TwigFunction('sizeForHumans', function ($bytes) {
                 $sizes = ['B', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'];
                 $factor = floor((strlen($bytes) - 1) / 3);
@@ -42,5 +51,25 @@ class ViewComposer
                 return sprintf('%.2f', $bytes / pow(1024, $factor)) . $sizes[$factor];
             })
         );
+
+        $this->registerThemeFunctions();
+    }
+
+    /**
+     * Register theme Twig functions.
+     *
+     * @return void
+     */
+    public function registerThemeFunctions(): void
+    {
+        $themeConfigPath = "app/themes/{$this->config->get('theme')}/config.php";
+
+        if (file_exists($themeConfigPath)) {
+            $themeConfig = include $themeConfigPath;
+        }
+
+        foreach ($themeConfig['functions'] ?? [] as $function) {
+            $this->twig->getEnvironment()->addFunction($function);
+        }
     }
 }
diff --git a/app/config/icons.php b/app/config/icons.php
deleted file mode 100644
index 016e79f..0000000
--- a/app/config/icons.php
+++ /dev/null
@@ -1,33 +0,0 @@
-<?php
-
-return [
-    'icons' => [
-        /** Images */
-        'gif' => 'fa-file-image',
-        'jpeg' => 'fa-file-image',
-        'jpg' => 'fa-file-image',
-        'png' => 'fa-file-image',
-
-        /** Data */
-        'csv' => 'fa-file-csv',
-        'json' => 'fa-file-code',
-        'yaml' => 'fa-file-alt',
-
-        /** Code */
-        'js' => 'fa-file-code',
-        'php' => 'fa-file-code',
-
-        /** Text and Markup */
-        'md' => 'fa-file-download',
-        'txt' => 'fa-file-alt',
-
-        /** Documents */
-        'doc' => 'fa-file-word',
-        'docx' => 'fa-file-word',
-        'pdf' => 'fa-file-pdf',
-        'ppt' => 'fa-file-powerpoint',
-        'pptx' => 'fa-file-powerpoint',
-        'xls' => 'fa-file-excel',
-        'xlsx' => 'fa-file-excel'
-    ]
-];
diff --git a/app/themes/default/config.php b/app/themes/default/config.php
new file mode 100644
index 0000000..041a58c
--- /dev/null
+++ b/app/themes/default/config.php
@@ -0,0 +1,17 @@
+<?php
+
+use Twig\TwigFunction;
+
+return [
+    /** Theme specific Twig functions */
+    'functions' => [
+        new TwigFunction('icon', function ($file) {
+            $icons = require __DIR__ . '/icons.php';
+
+            $icon = $file->isDir() ? 'fas fa-folder'
+                : $icons[$file->getExtension()] ?? 'fas fa-file';
+
+            return "<i class=\"{$icon} fa-fw fa-lg\"></i>";
+        })
+    ]
+];
diff --git a/app/themes/default/icons.php b/app/themes/default/icons.php
new file mode 100644
index 0000000..1a6d371
--- /dev/null
+++ b/app/themes/default/icons.php
@@ -0,0 +1,132 @@
+<?php
+
+return [
+    // Images
+    'ai' => 'fab fa-image',
+    'bmp' => 'fas fa-image',
+    'eps' => 'fab fa-image',
+    'gif' => 'fas fa-image',
+    'jpg' => 'fas fa-image',
+    'jpeg' => 'fas fa-image',
+    'png' => 'fas fa-image',
+    'ps' => 'fab fa-image',
+    'psd' => 'fas fa-image',
+    'svg' => 'fab fa-image',
+    'tga' => 'fas fa-image',
+    'tif' => 'fas fa-image',
+    'drw' => 'fab fa-image',
+
+    // Data
+    'csv' => 'fas fa-file-csv',
+    'json' => 'fas fa-file-alt',
+    'yaml' => 'fas fa-file-alt',
+
+    // Code
+    'c' => 'fas fa-code',
+    'class' => 'fas fa-code',
+    'cpp' => 'fas fa-code',
+    'css' => 'fab fab fa-css3',
+    'erb' => 'fas fa-code',
+    'htm' => 'fab fa-html5',
+    'html' => 'fab fa-html5',
+    'java' => 'fab fa-java',
+    'js' => 'fab fa-js',
+    'php' => 'fab fa-php',
+    'pl' => 'fas fa-code',
+    'py' => 'fab fa-python',
+    'rb' => 'fas fa-code',
+    'xhtml' => 'fas fa-code',
+    'xml' => 'fas fa-code',
+
+    // Text and Markup
+    'cfg' => 'fas fa-file-alt',
+    'ini' => 'fas fa-file-alt',
+    'log' => 'fas fa-file-alt',
+    'md' => 'fab fa-markdown',
+    'rtf' => 'fas fa-file-alt',
+    'txt' => 'fas fa-file-alt',
+
+    // Documents
+    'doc' => 'fas fa-file-word',
+    'docx' => 'fas fa-file-word',
+    'odt' => 'fas fa-file-alt',
+    'pdf' => 'fas fa-file-pdf',
+    'ppt' => 'fas fa-file-powerpoint',
+    'pptx' => 'fas fa-file-powerpoint',
+    'xls' => 'fas fa-file-excel',
+    'xlsx' => 'fas fa-file-excel',
+
+    // Archives
+    '7z' => 'fas fa-file-archive',
+    'bz' => 'fas fa-file-archive',
+    'gz' => 'fas fa-file-archive',
+    'rar' => 'fas fa-file-archive',
+    'tar' => 'fas fa-file-archive',
+    'zip' => 'fas fa-file-archive',
+
+    // Audio
+    'aac' => 'fas fa-music',
+    'flac' => 'fas fa-music',
+    'mid' => 'fas fa-music',
+    'midi' => 'fas fa-music',
+    'mp3' => 'fas fa-music',
+    'ogg' => 'fas fa-music',
+    'wma' => 'fas fa-music',
+    'wav' => 'fas fa-music',
+
+    // Databases
+    'accdb' => 'fas fa-database',
+    'db' => 'fas fa-database',
+    'dbf' => 'fas fa-database',
+    'mdb' => 'fas fa-database',
+    'pdb' => 'fas fa-database',
+    'sql' => 'fas fa-database',
+
+    // Executables
+    'app' => 'fas fa-window',
+    'bat' => 'fas fa-window',
+    'com' => 'fas fa-window',
+    'exe' => 'fas fa-window',
+    'jar' => 'fas fa-window',
+    'msi' => 'fas fa-window',
+    'vb' => 'fas fa-window',
+
+    // Fonts
+    'eot' => 'fas fa-font-case',
+    'otf' => 'fas fa-font-case',
+    'ttf' => 'fas fa-font-case',
+    'woff' => 'fas fa-font-case',
+
+    // Game Files
+    'gam' => 'fas fa-gamepad',
+    'nes' => 'fas fa-gamepad',
+    'rom' => 'fas fa-gamepad',
+    'sav' => 'fas fa-save',
+
+    // Package Files
+    'box' => 'fas fa-archive',
+    'deb' => 'fas fa-archive',
+    'rpm' => 'fas fa-archive',
+
+    // Scripts
+    'bat' => 'fas fa-terminal',
+    'cmd' => 'fas fa-terminal',
+    'sh' => 'fas fa-terminal',
+
+    // Video
+    'avi' => 'fas fa-video',
+    'flv' => 'fas fa-video',
+    'mkv' => 'fas fa-video',
+    'mov' => 'fas fa-video',
+    'mp4' => 'fas fa-video',
+    'mpg' => 'fas fa-video',
+    'ogv' => 'fas fa-video',
+    'webm' => 'fas fa-video',
+    'wmv' => 'fas fa-video',
+    'swf' => 'fas fa-video',
+
+    // Miscellaneous
+    'bak' => 'fas fa-save',
+    'lock' => 'fas fa-lock',
+    'msg' => 'fas fa-envelope',
+];
diff --git a/app/themes/default/index.twig b/app/themes/default/index.twig
index 6eafa9e..a95c51f 100644
--- a/app/themes/default/index.twig
+++ b/app/themes/default/index.twig
@@ -39,11 +39,7 @@
                     class="flex justify-between items-center rounded-lg p-4 hover:bg-gray-200 hover:p-4 hover:shadow"
                 >
                     <div class="flex-shrink text-gray-700 pr-2">
-                        {% if file.isDir %}
-                            <i class="fas fa-fw fa-lg fa-folder"></i>
-                        {% else %}
-                            <i class="fas fa-fw fa-lg {{ icon(file.getBasename) }}"></i>
-                        {% endif %}
+                        {{ icon(file) | raw }}
                     </div>
 
                     <div class="flex-grow truncate mr-2">
diff --git a/app/themes/default/src/sass/app.scss b/app/themes/default/src/sass/app.scss
index 9df2a36..8d48858 100644
--- a/app/themes/default/src/sass/app.scss
+++ b/app/themes/default/src/sass/app.scss
@@ -6,6 +6,7 @@
 // Icons
 $fa-font-path: "./webfonts";
 @import "~@fortawesome/fontawesome-free/scss/fontawesome.scss";
+@import "~@fortawesome/fontawesome-free/scss/brands.scss";
 @import "~@fortawesome/fontawesome-free/scss/solid.scss";
 
 // Fonts