5cf7f1b8c6
Indigo 500 (#3F51B5) is too dark on black backgrounds. Cobalt (#0050EF)
is a bright electric blue that meets contrast requirements on dark
surfaces without needing lighter fallback shades.
Replaced all hardcoded #9FA8DA (Indigo 200 workaround) with
{DynamicResource MahApps.Brushes.Accent} now that the accent is
naturally readable — section headings, price labels, detail labels,
listing URL link.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>