:root{
  --font-sans:"PingFang SC","Microsoft YaHei","Hiragino Sans GB","Helvetica Neue",Arial,sans-serif;
  --font-num:"SF Mono","Cascadia Code","Consolas",monospace;
  --font-size-base:13px;
}
body{
  font-family:var(--font-sans);
  font-size:var(--font-size-base);
  line-height:1.6;
  letter-spacing:0;
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
  font-feature-settings:"tnum" 1,"kern" 1;
  text-rendering:optimizeLegibility;
}