<html><head><style>h2 { outline-style: solid; outline-width: thin;}div.a { outline-style: solid; outline-width: thin; }div.b { border: 1px solid red; outline-style: solid; outline-width: thin;}</style></head><body><h1>outline-width 属性</h1><h2>具有细轮廓的标题</h2><div class="a">具有细轮廓的 div 元素。</div><br><div class="b">注意轮廓在任何边框之外。</div></body></html>