[PRO-73] Portal: Update hero images (#8381)

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## PR-Codex overview
This PR focuses on making stylistic updates to the `Hero` component in the `page.tsx` file, including adjustments to padding and text size in the layout.

### Detailed summary
- Changed padding in the `section` from `py-14` to `pt-14 pb-6`.
- Modified paragraph class from `text-lg` to `text-base` for smaller text size on smaller screens while keeping `lg:text-lg`.

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<!-- This is an auto-generated comment: release notes by coderabbit.ai -->

## Summary by CodeRabbit

* **Style**
  * Adjusted Hero section vertical spacing for improved layout balance.
  * Enhanced introductory text with responsive font sizing and refined spacing across different screen sizes.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: MananTank

apps/portal/src/app/_images/docs-hero-dark.png

@@ -41,14 +41,14 @@ export default function Page() {
 
 function Hero() {
   return (
-    <section className="grid gap-4 py-14 lg:grid-cols-[1fr_420px] lg:py-0">
+    <section className="grid gap-4 pt-14 pb-6 lg:grid-cols-[1fr_420px] lg:py-0">
       {/* Left */}
       <div className="flex flex-col justify-center">
         <div>
           <h1 className="mb-3 font-bold text-4xl tracking-tighter lg:text-6xl">
             thirdweb Documentation
           </h1>
-          <p className="mb-8 max-w-lg text-lg text-muted-foreground leading-normal text-pretty">
+          <p className="mb-6 max-w-lg text-base lg:text-lg text-muted-foreground leading-normal text-pretty">
             Platform for building the next generation of internet products
           </p>
           <div className="flex gap-3">