/* 嵌入模式：在学生工作台主区域 iframe 内显示时隐藏顶栏与页脚 */
body.embed-mode .header { display: none !important; }
body.embed-mode .footer { display: none !important; }
body.embed-mode main { margin-top: 0 !important; padding-top: 0 !important; }