Add Dark Mode Feature

[plasma-ai]

Summary

• Implemented full dark mode functionality with theme toggle button
• Added CSS custom properties for both light and dark themes
• Created theme toggle button with animated sun/moon icons
• Implemented localStorage persistence to remember user preferences
• Added system preference detection using prefers-color-scheme
• Theme syncs across all pages (index and team)

Changes Made

• Updated both index.html and team/index.html with theme support
• Replaced hardcoded colors with CSS variables
• Added theme toggle button (fixed position, top-right corner)
• JavaScript theme management with localStorage and system preference detection
• Smooth transitions between light and dark modes

Features

• Toggle button appears on all pages
• Theme preference persists across sessions
• Respects system dark/light mode preference on first visit
• Smooth animations and transitions
• Consistent styling across both themes

Test Plan

• Toggle between light and dark modes on index page
• Toggle between light and dark modes on team page
• Verify theme persists after page refresh
• Verify theme syncs across different pages
• Test responsive design in both themes
• Verify system preference detection works