style(design): consistency sweep + UX upgrades

- Palette: gray/zinc/slate/neutral → stein, red → fire, amber → erde,
  sky → himmel, green → wald
- Footer: replaced raw rgb with stein tokens
- Radius: unified to rounded-xs across cards, buttons, inputs, pagination
- Buttons: .btn-primary/.btn-secondary now font-medium; added secondary
- Card hover: -translate-y-0.5 + shadow + wald-300 border
- Header active link: wald border-bottom + wald-700 text
- Mobile nav: bigger touch targets + wald active accent
- Pagination: prev/next text labels + wald-500 active state with
  separated shape/color classes to avoid Tailwind conflicts
- Lead paragraph: scoped .markdown > p:first-child for top-level
  MarkdownBlock only via [data-block-type="markdown"]
- Section dividers: subtle wald-200 gradient between content rows
- Global focus-visible ring (wald-500)
- Inline hex → palette tokens (Badge amber, Tag custom-color contrast)
- Font weights snapped to design system (300/400/500/600/700)
- transition-all → transition-colors where only color changes
- Removed em-dashes from user-visible templates

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/lib/components/Footer.svelte

@@ -24,16 +24,16 @@
 
 {#if footer}
   <footer
-    class="mt-auto bg-zinc-950 text-white py-10"
+    class="mt-auto bg-stein-900 text-stein-0 py-10"
     data-footer-id={footer.id}
   >
     <div class="container-custom">
       {#if hasRowContent}
-        <div class="content-footer text-sm text-zinc-200">
+        <div class="content-footer text-sm text-stein-200">
           <ContentRows layout={footer} translations={translations} />
         </div>
       {:else}
-        <p class="text-sm text-white/80 text-center">
+        <p class="text-sm text-stein-0/80 text-center">
           {t(T.footer_copyright) !== T.footer_copyright
             ? t(T.footer_copyright)
             : `© ${new Date().getFullYear()} Windwiderstand`}
@@ -61,19 +61,19 @@
   .content-footer :global(.content-row + .content-row) {
     margin-top: 2rem;
     padding-top: 1.5rem;
-    border-top: 1px solid rgb(63 63 70);
+    border-top: 1px solid var(--color-stein-700);
   }
   .content-footer :global(a) {
-    color: rgb(228 228 231);
+    color: var(--color-stein-200);
   }
   .content-footer :global(a:hover) {
-    color: rgb(255 255 255);
+    color: var(--color-stein-0);
   }
   .content-footer :global(h3) {
-    color: rgb(250 250 250);
+    color: var(--color-stein-0);
   }
   .content-footer :global(.markdown),
   .content-footer :global(.prose) {
-    color: rgb(212 212 216);
+    color: var(--color-stein-200);
   }
 </style>