Security & UX Update: Custom session codes, admin session take-over, secure presentation tokens, and SVG/CSS branding assets

public/present.html

@@ -14,10 +14,13 @@
     <style>
         body {
             font-family: system-ui, -apple-system, sans-serif;
-            background: #111111 url('/img/bg.png') center/cover fixed;
-
+            background: #111111;
+            background-image:
+                radial-gradient(ellipse at 20% 50%, rgba(220, 38, 38, 0.08) 0%, transparent 50%),
+                radial-gradient(ellipse at 80% 50%, rgba(245, 158, 11, 0.06) 0%, transparent 50%);
         }
 
+        /* Answer colors for presentation view */
         .answer-a {
             background: #dc2626;
         }
@@ -34,6 +37,7 @@
             background: #16a34a;
         }
 
+        /* Fire gradient for headings */
         .fire-gradient {
             background: linear-gradient(135deg, #dc2626, #f59e0b);
             -webkit-background-clip: text;