效果

请按你的喜好选择使用。

方案

方案 A：直接拷贝下面这段代码，粘贴到设计器中

{"type":"nodeSchema","componentsMap":{},"componentsTree":[{"componentName":"Html","props":{"content":"<style type=\"text/css\">\n\thtml,\n\tbody {\n\t\tfilter: grayscale(100%) !important;\n\t\t-webkit-filter: grayscale(100%) !important;\n\t\t-webkit-filter: grayscale(1) !important;\n\t}\n</style>","__style__":{},"fieldId":"html_lb3s75cm"},"hidden":false,"title":"","isLocked":false,"condition":true,"conditionGroup":""}]}

方案 B：在动作面板中，通过 JavaScript 实现

(() => {
  const style = document.createElement('style');
  style.type = 'text/css';
  style.innerHTML = `
    html, body {
      filter: grayscale(100%) !important;
      -webkit-filter: grayscale(100%) !important;
      -webkit-filter: grayscale(1) !important;
    }
`;
  document.head.appendChild(style);
})();

方案 C：在页面样式中写入如下 CSS

页面属性-样式-源码编辑

html,
body {
  filter: grayscale(100%) !important;
  -webkit-filter: grayscale(100%) !important;
  -webkit-filter: grayscale(1) !important;
}

其他方案可以自行在搜索引擎搜索