Hopefully this works.

Pages/Bits/Head.php

@@ -1,8 +1,20 @@
 <head>
     <meta charset="UTF-8">
-    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <meta
+        name="viewport"
+        content="width=device-width, initial-scale=1.0"
+    >
 
-    <title>Sarah's garden</title>
+    <title>
+        <?= htmlspecialchars(
+            "SG/" . ($PageTitle ?? "Home"),
+            ENT_QUOTES,
+            "UTF-8"
+        ) ?>
+    </title>
 
-    <link rel="stylesheet" href="../../Styles/Style.css">
+    <link
+        rel="stylesheet"
+        href="<?= $RootPath ?>Styles/Style.css"
+    >
 </head>