diff --git a/.php-cs-fixer.dist.php b/.php-cs-fixer.dist.php
index f2bd1ae1..f0d116ab 100644
--- a/.php-cs-fixer.dist.php
+++ b/.php-cs-fixer.dist.php
@@ -14,6 +14,4 @@ return $config->setRules([
         'array_syntax' => ['syntax' => 'short'],
     ])
     ->setFinder($finder)
-;
-
-?>
+;
\ No newline at end of file
diff --git a/core/install.php b/core/install.php
index eff930c0..bee62aa7 100644
--- a/core/install.php
+++ b/core/install.php
@@ -1,4 +1,7 @@
 <?php
+
+declare(strict_types=1);
+
 /**
  * Shimmie Installer
  *
diff --git a/ext/download/events.php b/ext/download/events.php
index 477bb50a..51804543 100644
--- a/ext/download/events.php
+++ b/ext/download/events.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 class ImageDownloadingEvent extends Event
 {
     public Image $image;
diff --git a/ext/download/info.php b/ext/download/info.php
index 46fb1882..f6f56dba 100644
--- a/ext/download/info.php
+++ b/ext/download/info.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 class DownloadInfo extends ExtensionInfo
 {
     public const KEY = "download";
diff --git a/ext/download/main.php b/ext/download/main.php
index 23aa6092..feb1a409 100644
--- a/ext/download/main.php
+++ b/ext/download/main.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 require_once "events.php";
 
 class Download extends Extension
diff --git a/ext/upload/config.php b/ext/upload/config.php
index 751c4995..3e3666e1 100644
--- a/ext/upload/config.php
+++ b/ext/upload/config.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 class UploadConfig
 {
     public const COUNT = "upload_count";
diff --git a/tests/defines.php b/tests/defines.php
index ac6d4103..ee971e0d 100644
--- a/tests/defines.php
+++ b/tests/defines.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 define("UNITTEST", true);
 define("EXTRA_EXTS", str_replace("ext/", "", implode(',', glob('ext/*'))));
 
diff --git a/tests/router.php b/tests/router.php
index 01743048..56f963a0 100644
--- a/tests/router.php
+++ b/tests/router.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 // custom routing for stand-alone mode, basically
 // .htaccess for the built-in php web server
 if (PHP_SAPI !== 'cli-server') {
diff --git a/themes/rule34v2/home.theme.php b/themes/rule34v2/home.theme.php
index 260d9451..54e67cc6 100644
--- a/themes/rule34v2/home.theme.php
+++ b/themes/rule34v2/home.theme.php
@@ -1,10 +1,12 @@
 <?php
 
+declare(strict_types=1);
+
 class CustomHomeTheme extends HomeTheme
 {
     public function display_page(Page $page, string $sitename, string $base_href, string $theme_name, string $body): void
     {
-        $page->set_mode("data");
+        $page->set_mode(PageMode::DATA);
         $page->add_auto_html_headers();
         $hh = $page->get_all_html_headers();
         $page->set_data(
diff --git a/themes/rule34v2/index.theme.php b/themes/rule34v2/index.theme.php
index 1d9091b8..7ab04133 100644
--- a/themes/rule34v2/index.theme.php
+++ b/themes/rule34v2/index.theme.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 class CustomIndexTheme extends IndexTheme
 {
     protected function build_table(array $images, ?string $query): string
diff --git a/themes/rule34v2/tag_edit.theme.php b/themes/rule34v2/tag_edit.theme.php
index 4e92654e..e1490d74 100644
--- a/themes/rule34v2/tag_edit.theme.php
+++ b/themes/rule34v2/tag_edit.theme.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 class CustomTagEditTheme extends TagEditTheme
 {
     public function get_tag_editor_html(Image $image): string
diff --git a/themes/rule34v2/themelet.class.php b/themes/rule34v2/themelet.class.php
index 54836e5e..530b98e6 100644
--- a/themes/rule34v2/themelet.class.php
+++ b/themes/rule34v2/themelet.class.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 class Themelet extends BaseThemelet
 {
     public function build_thumb_html(Image $image): string
diff --git a/themes/rule34v2/upload.theme.php b/themes/rule34v2/upload.theme.php
index 95d310d3..e08416a5 100644
--- a/themes/rule34v2/upload.theme.php
+++ b/themes/rule34v2/upload.theme.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 use MicroHTML\HTMLElement;
 
 use function MicroHTML\A;