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/atom/views/components/content/guest-content-card.blade.php

@@ -7,10 +7,10 @@
  </div>
 
  <div class="flex flex-col">
- <p class="font-semibold text-black dark:text-gray-200">{{ $title }}</p>
+ <p class="font-semibold text-body">{{ $title }}</p>
 
  @if(isset($underTitle))
- <p class="dark:text-gray-500">{{ $underTitle }}</p>
+ <p class="text-muted">{{ $underTitle }}</p>
  @endif
  </div>
  </div>