diff --git a/classes/article.php b/classes/article.php
index e9f86f298..398132d12 100644
--- a/classes/article.php
+++ b/classes/article.php
@@ -44,7 +44,7 @@ class Article extends Handler_Protected {
 		} else if ($mode == "raw") {
 			if ($_REQUEST['html']) {
 				header("Content-Type: text/html");
-				print '<link rel="stylesheet" type="text/css" href="tt-rss.css"/>';
+				print '<link rel="stylesheet" type="text/css" href="css/tt-rss.css"/>';
 			}
 
 			$article = format_article($id, false);
diff --git a/classes/handler/public.php b/classes/handler/public.php
index 7fa744107..3e868d56e 100644
--- a/classes/handler/public.php
+++ b/classes/handler/public.php
@@ -382,7 +382,7 @@ class Handler_Public extends Handler {
 		header('Content-Type: text/html; charset=utf-8');
 		print "<html><head><title>Tiny Tiny RSS</title>";
 
-		stylesheet_tag("utility.css");
+		stylesheet_tag("css/utility.css");
 		javascript_tag("lib/prototype.js");
 		javascript_tag("lib/scriptaculous/scriptaculous.js?load=effects,dragdrop,controls");
 		print "<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\"/>
@@ -553,7 +553,7 @@ class Handler_Public extends Handler {
 			print "<html>
 				<head>
 					<title>Tiny Tiny RSS</title>
-					<link rel=\"stylesheet\" type=\"text/css\" href=\"utility.css\">
+					<link rel=\"stylesheet\" type=\"text/css\" href=\"css/utility.css\">
 					<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\"/>
 				</head>
 				<body>
@@ -735,7 +735,7 @@ class Handler_Public extends Handler {
 		header('Content-Type: text/html; charset=utf-8');
 		print "<html><head><title>Tiny Tiny RSS</title>";
 
-		stylesheet_tag("utility.css");
+		stylesheet_tag("css/utility.css");
 		javascript_tag("lib/prototype.js");
 
 		print "<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\"/>
@@ -835,7 +835,7 @@ class Handler_Public extends Handler {
 			<head>
 			<title>Database Updater</title>
 			<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
-			<link rel="stylesheet" type="text/css" href="utility.css"/>
+			<link rel="stylesheet" type="text/css" href="css/utility.css"/>
 			</head>
 			<style type="text/css">
 				span.ok { color : #009000; font-weight : bold; }
diff --git a/classes/opml.php b/classes/opml.php
index 3f4030dea..b37b72c21 100644
--- a/classes/opml.php
+++ b/classes/opml.php
@@ -24,7 +24,7 @@ class Opml extends Handler_Protected {
 
 		print "<html>
 			<head>
-				<link rel=\"stylesheet\" href=\"utility.css\" type=\"text/css\">
+				<link rel=\"stylesheet\" href=\"css/utility.css\" type=\"text/css\">
 				<title>".__("OPML Utility")."</title>
 				<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\"/>
 			</head>
diff --git a/classes/pref/prefs.php b/classes/pref/prefs.php
index 077addf41..32071e3b3 100644
--- a/classes/pref/prefs.php
+++ b/classes/pref/prefs.php
@@ -962,7 +962,7 @@ class Pref_Prefs extends Handler_Protected {
 
 		$value = str_replace("<br/>", "\n", $value);
 
-		print_notice(T_sprintf("You can override colors, fonts and layout of your currently selected theme with custom CSS declarations here. <a target=\"_blank\" class=\"visibleLink\" href=\"%s\">This file</a> can be used as a baseline.", "tt-rss.css"));
+		print_notice(T_sprintf("You can override colors, fonts and layout of your currently selected theme with custom CSS declarations here. <a target=\"_blank\" class=\"visibleLink\" href=\"%s\">This file</a> can be used as a baseline.", "css/tt-rss.css"));
 
 		print "<input dojoType=\"dijit.form.TextBox\" style=\"display : none\" name=\"op\" value=\"rpc\">";
 		print "<input dojoType=\"dijit.form.TextBox\" style=\"display : none\" name=\"method\" value=\"setpref\">";
diff --git a/cdm.css b/css/cdm.css
similarity index 100%
rename from cdm.css
rename to css/cdm.css
diff --git a/prefs.css b/css/prefs.css
similarity index 100%
rename from prefs.css
rename to css/prefs.css
diff --git a/tt-rss.css b/css/tt-rss.css
similarity index 100%
rename from tt-rss.css
rename to css/tt-rss.css
diff --git a/utility.css b/css/utility.css
similarity index 100%
rename from utility.css
rename to css/utility.css
diff --git a/include/functions.php b/include/functions.php
index 2a8c23b5d..328b00c8a 100644
--- a/include/functions.php
+++ b/include/functions.php
@@ -3126,7 +3126,7 @@
 				$rv['content'] .= "<html><head>
 						<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\"/>
 						<title>Tiny Tiny RSS - ".$line["title"]."</title>
-						<link rel=\"stylesheet\" type=\"text/css\" href=\"tt-rss.css\">
+						<link rel=\"stylesheet\" type=\"text/css\" href=\"css/tt-rss.css\">
 					</head><body id=\"ttrssZoom\">";
 			}
 
diff --git a/include/login_form.php b/include/login_form.php
index ba31615ea..0637c453a 100644
--- a/include/login_form.php
+++ b/include/login_form.php
@@ -2,7 +2,7 @@
 <head>
 	<title>Tiny Tiny RSS : Login</title>
 	<link rel="stylesheet" type="text/css" href="lib/dijit/themes/claro/claro.css"/>
-	<link rel="stylesheet" type="text/css" href="tt-rss.css">
+	<link rel="stylesheet" type="text/css" href="css/tt-rss.css">
 	<link rel="shortcut icon" type="image/png" href="images/favicon.png">
 	<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
 	<script type="text/javascript" src="lib/dojo/dojo.js"></script>
diff --git a/include/sanity_check.php b/include/sanity_check.php
index b2888b1d7..29e53fa33 100644
--- a/include/sanity_check.php
+++ b/include/sanity_check.php
@@ -160,7 +160,7 @@
 			<head>
 			<title>Startup failed</title>
 				<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
-				<link rel="stylesheet" type="text/css" href="utility.css">
+				<link rel="stylesheet" type="text/css" href="css/utility.css">
 			</head>
 		<body>
 		<div class="floatingLogo"><img src="images/logo_small.png"></div>
diff --git a/index.php b/index.php
index c43d2db4a..c3fe770f5 100644
--- a/index.php
+++ b/index.php
@@ -57,13 +57,13 @@
 	<title>Tiny Tiny RSS</title>
 
 	<?php stylesheet_tag("lib/dijit/themes/claro/claro.css"); ?>
-	<?php stylesheet_tag("tt-rss.css"); ?>
-	<?php stylesheet_tag("cdm.css"); ?>
 
 	<?php if ($_SESSION["uid"]) {
 		$theme = get_pref( "USER_CSS_THEME", $_SESSION["uid"], false);
-		if ($theme) {
+		if ($theme && file_exists("themes/$theme")) {
 			stylesheet_tag("themes/$theme");
+		} else {
+			stylesheet_tag("themes/default.css");
 		}
 	}
 	?>
diff --git a/install/index.php b/install/index.php
index 6cb2ace4f..efa917d95 100644
--- a/install/index.php
+++ b/install/index.php
@@ -2,7 +2,7 @@
 <head>
 	<title>Tiny Tiny RSS - Installer</title>
 	<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
-	<link rel="stylesheet" type="text/css" href="../utility.css">
+	<link rel="stylesheet" type="text/css" href="../css/utility.css">
 	<style type="text/css">
 	textarea { font-size : 12px; }
 	</style>
diff --git a/plugins/auth_internal/init.php b/plugins/auth_internal/init.php
index 87c8555c0..3c38ab8bf 100644
--- a/plugins/auth_internal/init.php
+++ b/plugins/auth_internal/init.php
@@ -51,7 +51,7 @@ class Auth_Internal extends Plugin implements IAuthModule {
 							$return = urlencode($_REQUEST["return"]);
 							?><html>
 								<head><title>Tiny Tiny RSS</title></head>
-								<?php stylesheet_tag("utility.css") ?>
+								<?php stylesheet_tag("css/utility.css") ?>
 							<body class="otp"><div class="content">
 							<form action="public.php?return=<?php echo $return ?>"
 									method="POST" class="otpform">
diff --git a/prefs.php b/prefs.php
index 93b7cbb78..2cee534b1 100644
--- a/prefs.php
+++ b/prefs.php
@@ -33,13 +33,13 @@
 	<title>Tiny Tiny RSS : <?php echo __("Preferences") ?></title>
 
 	<?php stylesheet_tag("lib/dijit/themes/claro/claro.css"); ?>
-	<?php stylesheet_tag("tt-rss.css"); ?>
-	<?php stylesheet_tag("prefs.css"); ?>
 
 	<?php if ($_SESSION["uid"]) {
 		$theme = get_pref( "USER_CSS_THEME", $_SESSION["uid"], false);
-		if ($theme) {
+		if ($theme && file_exists("themes/$theme")) {
 			stylesheet_tag("themes/$theme");
+		} else {
+			stylesheet_tag("themes/default.css");
 		}
 	}
 	?>
diff --git a/register.php b/register.php
index 5bc6563b0..f50ef14a4 100644
--- a/register.php
+++ b/register.php
@@ -93,7 +93,7 @@
 <head>
 <title>Create new account</title>
 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
-<link rel="stylesheet" type="text/css" href="utility.css">
+<link rel="stylesheet" type="text/css" href="css/utility.css">
 <script type="text/javascript" src="js/functions.js"></script>
 <script type="text/javascript" src="lib/prototype.js"></script>
 <script type="text/javascript" src="lib/scriptaculous/scriptaculous.js?load=effects,dragdrop,controls"></script>
diff --git a/themes/default.css b/themes/default.css
index e69de29bb..83e15257b 100644
--- a/themes/default.css
+++ b/themes/default.css
@@ -0,0 +1,3 @@
+@import "../css/tt-rss.css";
+@import "../css/cdm.css";
+@import "../css/prefs.css";
diff --git a/update.php b/update.php
index f542a390b..5e4a5ab79 100755
--- a/update.php
+++ b/update.php
@@ -47,7 +47,7 @@
 		<head>
 		<title>Tiny Tiny RSS data update script.</title>
 		<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
-		<link rel="stylesheet" type="text/css" href="utility.css">
+		<link rel="stylesheet" type="text/css" href="css/utility.css">
 		</head>
 
 		<body>
