Site map: switch heading + subtitle + card descs to JetBrains Mono

All copy in the "What's inside" band now shares one type system:
JetBrains Mono on every line (eyebrow, h2, subtitle, card labels,
descriptions). Sizes/weights adjusted because mono reads heavier than
Inter at the same px — h2 32px/500, subtitle 13px/400, desc 12px/400 —
so the editorial hierarchy stays intact and lines don't bulk up.

Co-authored-by: Cursor <cursoragent@cursor.com>

assets/styles/section-intro.css

@@ -210,25 +210,27 @@
 }
 .intro-sitemap__title {
   margin: 0;
-  font-family: "Inter", "Helvetica Neue", sans-serif;
-  font-size: 40px;
-  font-weight: 400;
-  letter-spacing: -0.02em;
-  line-height: 1.1;
+  font-family: "JetBrains Mono", ui-monospace, monospace;
+  font-size: 32px;
+  font-weight: 500;
+  letter-spacing: -0.005em;
+  line-height: 1.15;
   color: var(--ink);
 }
 .intro-sitemap__subtitle {
-  margin: 14px auto 0;
-  max-width: 520px;
-  font-family: "Inter", "Helvetica Neue", sans-serif;
-  font-size: 14px;
-  font-weight: 300;
+  margin: 16px auto 0;
+  max-width: 560px;
+  font-family: "JetBrains Mono", ui-monospace, monospace;
+  font-size: 13px;
+  font-weight: 400;
+  letter-spacing: 0;
   line-height: 1.55;
   color: var(--ink-soft);
 }
 @media (max-width: 720px) {
   .intro-sitemap__heading { margin-bottom: 36px; }
-  .intro-sitemap__title { font-size: 30px; }
+  .intro-sitemap__title { font-size: 24px; }
+  .intro-sitemap__subtitle { font-size: 12.5px; }
 }
 .intro-sitemap__steps {
   list-style: none;
@@ -314,9 +316,10 @@
 }
 .intro-sitemap__desc {
   margin: 0;
-  font-family: "Inter", "Helvetica Neue", sans-serif;
-  font-size: 13px;
-  font-weight: 300;
+  font-family: "JetBrains Mono", ui-monospace, monospace;
+  font-size: 12px;
+  font-weight: 400;
+  letter-spacing: 0;
   line-height: 1.55;
   color: var(--ink-soft);
 }