Improve text visibility in atom and dusk themes

- Add CSS variable support to dusk theme components for dynamic text colors
- Fix low-contrast preset color combinations (cyberpunk, neon, magma, forest, obsidian, space)
- Add text-shadow utility classes and apply to site header and backgrounds
- Style logout buttons as proper buttons matching other button styles
- Fix hardcoded text colors in atom theme components

resources/themes/dusk/views/components/article-card.blade.php

@@ -1,7 +1,7 @@
 @props(['article'])
 
 <div class="swiper-slide relative article-image rounded-lg overflow-hidden" style="background-image: url({{ asset('storage/' . $article->image) }})">
-    <div class="absolute h-[90px] w-full left-0 bottom-0 bg-[#171a23]/95 text-white py-2 px-4">
+    <div class="absolute h-[90px] w-full left-0 bottom-0 py-2 px-4 text-shadow" style="background-color: var(--color-surface); color: var(--color-text);">
         <h2 class="text-xl font-bold truncate">
             {{ $article->title }}
         </h2>