.menu{background-color:#e5e7eb;border:1px solid #ccc;margin:20px 0;padding:20px}.menu:before{content:"Nội dung bài viết:";text-decoration:underline}.menu .menu-level-1{padding:0;font-weight:700}.menu .menu-level-2{padding-left:20px;font-weight:500}.menu .menu-level-3{padding-left:40px}