vant-weapp/zui/color/index.wxss

.zui-c-red {
  color: #f44 !important;
}

.zui-c-gray {
  color: #c9c9c9 !important;
}

.zui-c-gray-dark {
  color: #999 !important;
}

.zui-c-gray-darker {
  color: #666 !important;
}

.zui-c-black {
  color: #333 !important;
}

.zui-c-blue {
  color: #3283fa !important;
}

.zui-c-green {
  color: #44BB00 !important;
}