front page enhancements

app/lessons/unit-4-ratio-proportion/page.tsx

@@ -16,7 +16,7 @@ export default function Unit4Overview() {
         ]}
       />
       <div className="mb-10">
-        <Badge variant="unit-4" className="mb-3">Unit 4 &mdash; {unit.weeks}</Badge>
+        <Badge variant="unit-4" className="mb-3">Unit 4</Badge>
         <h1 className="mb-2 text-3xl font-bold tracking-tight">{unit.title}</h1>
         <p className="text-muted leading-relaxed">{unit.description}</p>
       </div>
@@ -28,7 +28,6 @@ export default function Unit4Overview() {
                 <span className="flex h-7 w-7 items-center justify-center rounded-lg bg-unit-4-light text-xs font-bold text-unit-4-dark shadow-[var(--shadow-sm)]">
                   {String.fromCharCode(97 + i)}
                 </span>
-                <span className="text-xs text-muted">Week {topic.week}</span>
               </div>
               <h3 className="mb-1 font-semibold">{topic.title}</h3>
               <p className="text-sm leading-relaxed text-muted">{topic.description}</p>