Optimize homepage UI and search bar styling and interactions.

[ZeddYu]

Summary

Optimize homepage UI and Chrome extension search bar styling and interactions.

New Features

• CSS Variable System: Establish a complete CSS variable system for unified design tokens, including colors, fonts, shadows, and border radius
• Skeleton Loading: Add a skeleton screen component for a better loading experience
• Countdown Urgency Colors: Display different colors based on remaining time: normal → attention → warning → urgent

UI Improvements

• Responsive Filter: Add a mobile filter drawer panel for a better mobile experience
• Enhanced Search Bar: Add a search icon, clear button, and focus ring effect
• Table Hover Effect: Add row highlight on hover
• Star Icon Styling: Add cursor, transition, and font-size styles
• Container Width: Increase homepage max-width from 980px to 1200px

Files Changed

• public/styles.css - CSS variables, skeleton styles, responsive layout
• src/components/countdown.rs - Countdown urgency levels
• src/components/loading.rs - New skeleton component
• src/components/showtable.rs - Responsive filter, row hover effect
• extensions/chrome/popup.html - Search icon and clear button
• extensions/chrome/popup.css - Search bar styling, focus state
• extensions/chrome/popup.js - Clear button interaction logic

Related issue

#653

[mergify]

Welcome to ccf-deadlines!
We're delighted to have you onboard (p≧w≦q)

[mergify]

Great job!
Thank you @ZeddYu for your contribution!