style(calendar): 优化css变量

[xiaoyatong]

🤔 这个变动的性质是？

• 新特性提交
• 日常 bug 修复
• 站点、文档改进
• 演示代码改进
• 组件样式/交互改进
• TypeScript 定义更新
• 包体积优化
• 性能优化
• 功能增强
• 国际化改进
• 重构
• 代码风格优化
• 测试用例
• 分支合并
• 其他改动（是关于什么的改动？）

🔗 相关 Issue

💡 需求背景和解决方案

☑️ 请求合并前的自查清单

⚠️ 请自检并全部勾选全部选项。⚠️

• 文档已补充或无须补充
• 代码演示已提供或无须提供
• TypeScript 定义已补充或无须补充
• fork仓库代码是否为最新避免文件冲突
• Files changed 没有 package.json lock 等无关文件

[codecov]

Codecov Report

Attention: 4 lines in your changes are missing coverage. Please review.

Comparison is base (045bc5e) 74.08% compared to head (f0c0ac9) 74.05%.
Report is 2 commits behind head on next.

Files	Patch %	Lines
src/packages/noticebar/noticebar.tsx	55.55%	2 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             next    #1753      +/-   ##
==========================================
- Coverage   74.08%   74.05%   -0.04%     
==========================================
  Files         211      211              
  Lines        8610     8614       +4     
  Branches     2458     2462       +4     
==========================================
  Hits         6379     6379              
- Misses       2022     2024       +2     
- Partials      209      211       +2     

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