copy: add intro text and scale hint to radar chart

Make the radar chart more approachable for first-time visitors by
adding a plain-language explanation and inline scale legend.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: pavelkucera

src/components/CategoryTrendChart.tsx

@@ -253,6 +253,14 @@ export default function CategoryTrendChart() {
 
   return (
     <div>
+      {/* Intro + scale hint */}
+      <p style={{ color: '#94a3b8', fontSize: '0.85rem', lineHeight: 1.6, marginBottom: '0.4rem' }}>
+        Nine skill areas, mapped for each decade. The bigger the shape, the more the industry demanded. Pick two years to compare.
+      </p>
+      <p style={{ color: '#64748b', fontSize: '0.78rem', marginBottom: '1rem' }}>
+        Scale: 0 = not on the radar · 5 = nice to have · 8 = must-have for seniors · 10 = everyone needs it
+      </p>
+
       {/* Year selector */}
       <div style={{ marginBottom: '0.6rem' }}>
         <div style={{

src/pages/index.astro

@@ -14,7 +14,7 @@ import ComplexityChart from '../components/ComplexityChart';
   <ChartSection
     id="category-trends"
     title="Skill Radar — Then vs Now"
-    subtitle="Average category expectation · Compare any two years"
+    subtitle="What skills did the industry expect from senior developers — and how did that change over time?"
   >
     <CategoryTrendChart client:only="react" />
   </ChartSection>