fix relative css

Author: Kezii

templates/base.html

@@ -5,8 +5,8 @@
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <title>End Summer Camp &#8211; Hacking * Free Software * DIY</title>
-    <link rel="stylesheet" href="main.css">
-    <link rel="manifest" href="manifest.webmanifest">
+    <link rel="stylesheet" href="/main.css">
+    <link rel="manifest" href="/manifest.webmanifest">
     <link rel="icon" type="image/png"  href="/images/favicon/favicon_64.png" sizes="64x64">
 
     <meta name="keywords"