fix: opacity fotos + audit completo + rollback legal pages

- Hero: Maldonado aerial opacity 0.12→0.30
- DifferenceCards: card photo opacity 0.06→0.15
- ProcessSteps: section photo opacity 0.05→0.15
- servicios/[slug] + en mirror: full Tailwind v3→CSS vars migration
- PricingTiers + PricingTiersFeatured: rounded-2xl→glass-card
- en/plans: hardcoded Spanish H1→i18n + reveal
- planes, servicios/index, en/servicios/index: reveal en hero
- legal pages: bg-hds-marfil+text-hds-humo→CSS vars

src/pages/en/legal/terms.astro

@@ -9,10 +9,10 @@ const lang = getLangFromUrl(Astro.url);
   description={lang === 'en' ? 'Terms of service of Hosting del Sur.' : 'Términos del servicio de Hosting del Sur.'}
   lang={lang}
 >
-  <article class="py-16 md:py-20 bg-hds-marfil">
+  <article class="py-16 md:py-20" style="background: var(--hds-bg);">
     <div class="max-w-3xl mx-auto px-4 sm:px-6 lg:px-8 prose prose-lg">
-      <h1>{lang === 'en' ? 'Terms of service' : 'Términos del servicio'}</h1>
-      <p class="text-sm text-hds-humo">
+      <h1>{lang === 'en' ? 'Terms and conditions' : 'Términos y condiciones'}</h1>
+      <p class="text-sm" style="color: var(--hds-fg-muted);">
         {lang === 'en' ? 'Last updated' : 'Última actualización'}: 2026
       </p>