refactor(design): migrate homepage to typography utility classes

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Change-Id: Iab12a65e56e6d207be662e98fbfc3beca04b2763

Author: jd

src/content/docs/index.mdx

@@ -14,8 +14,8 @@ import Button from '~/components/Button.astro';
 
   <div class="home-hero">
     <div class="hero-inner">
-      <h1 class="content-title">Ship Code Faster, Break Less</h1>
-      <div class="tagline content-subtitle">
+      <h1 class="heading-hero">Ship Code Faster, Break Less</h1>
+      <div class="tagline text-subtitle">
         Mergify eliminates broken builds, tames flaky tests, and
         cuts CI waste—so your team ships with confidence.
       </div>
@@ -41,7 +41,7 @@ import Button from '~/components/Button.astro';
 
   {/* -------------- PROBLEM-SOLUTION CARDS -------------- */}
 
-  <h2 class="home-title">What Problem Are You Solving?</h2>
+  <h2 class="heading-section">What Problem Are You Solving?</h2>
 
   <div class="home-problems">
     <a href="/merge-queue" class="home-problem-card">
@@ -69,7 +69,7 @@ import Button from '~/components/Button.astro';
 
   {/* -------------- PRODUCT OVERVIEW -------------- */}
 
-  <h2 class="home-title">Products</h2>
+  <h2 class="heading-section">Products</h2>
 
   <DocsetGrid>
     <Docset title="Merge Queue" path="/merge-queue" icon="octicon:git-merge-queue-16">
@@ -85,7 +85,7 @@ import Button from '~/components/Button.astro';
 
   {/* -------------- GET STARTED -------------- */}
 
-  <h2 class="home-title">Get Started</h2>
+  <h2 class="heading-section">Get Started</h2>
 
   <div class="home-get-started">
     <Button variant="primary" href="/merge-queue/setup" target="_self">Set up Merge Queue</Button>
@@ -102,7 +102,7 @@ import Button from '~/components/Button.astro';
 
   {/* -------------- REFERENCE -------------- */}
 
-  <h2 class="home-title">Reference</h2>
+  <h2 class="heading-section">Reference</h2>
 
   [Configuration](/configuration/file-format) ·
   [Conditions](/configuration/conditions) ·
@@ -137,7 +137,7 @@ import Button from '~/components/Button.astro';
   {/* -------------- COMMUNITY -------------- */}
 
   <section class="community">
-    <h2 class="home-title">Community</h2>
+    <h2 class="heading-section">Community</h2>
     <p>Share feedback, ask questions, and see what other teams build with Mergify.</p>
     <div class="community-buttons">
       <CommunityButton href="https://github.com/Mergifyio/mergify/discussions" icon="simple-icons:github" />

src/styles/index.css

@@ -1033,12 +1033,3 @@ article.content {
   font-size: var(--text-sm);
   color: rgba(255, 255, 255, 0.9);
 }
-
-/* Home page: Section title */
-.home-title {
-  font-size: var(--text-2xl);
-  font-weight: 500;
-  letter-spacing: -0.025em;
-  margin-top: 2rem;
-  margin-bottom: 1rem;
-}