Update webapp - fix hero animation scroll + dark background

- Fixed animation height to 100vh to prevent squeeze on scroll
- Added dark slate-900 background for transparent animation

app/components/hero/HeroBackground.vue

@@ -1,5 +1,5 @@
 <template>
-  <div class="absolute inset-0 overflow-hidden">
+  <div class="absolute inset-0 overflow-hidden bg-slate-900">
     <!-- Lottie animation -->
     <ClientOnly>
       <DotLottieVue
@@ -7,8 +7,9 @@
         autoplay
         loop
         :layout="{ fit: 'cover', align: [0.5, 0.5] }"
-        class="absolute inset-0 w-full h-full"
+        class="absolute top-0 left-0 w-full"
         :style="{
+          height: '100vh',
           opacity: 1 - collapseProgress * 0.7,
           transform: `scale(${1 + collapseProgress * 0.1})`
         }"