Refactor Members Directory and Newsletter Archive styles to use new color palette

- Updated color classes in MembersDirectory.js to use new color variables for borders, backgrounds, and text.
- Enhanced visual consistency by replacing hardcoded colors with Tailwind CSS color utilities.
- Modified NewsletterArchive.js to align with the new design system, ensuring a cohesive look across components.
- Added new color variables in tailwind.config.js for better maintainability and scalability.

.crossnote/style.less

@@ -0,0 +1,8 @@
+
+/* Please visit the URL below for more information: */
+/*   https://shd101wyy.github.io/markdown-preview-enhanced/#/customize-css */
+
+.markdown-preview.markdown-preview {
+  // modify your style here
+  // eg: background-color: blue;
+}