Html 我不知道如何附加方括号中的属性名

我不知道怎么用这个。我用不同的方法试过，但都不管用

abbr[title] { border-bottom: 4px dotted green }

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以下是有关如何完成附加和属性名称的文档：

下面是使用这些属性选择器的演示：

HTML:

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非常有帮助！谢谢。这是有效的css，它将相应地为所有元素设置样式，前提是它们指定了title属性。这就是你的目标吗？请你能提供你的html吗？

<div class="hello-example">
    <a href="http://example.com">English:</a>
    <span lang="en-us en-gb en-au en-nz">Hello World!</span>
</div>
<div class="hello-example">
    <a href="#portuguese">Portuguese:</a>
    <span lang="pt">Olá Mundo!</span>
</div>
<div class="hello-example">
    <a href="http://example.cn">Chinese (Simplified):</a>
    <span lang="zh-CN">世界您好！</span>
</div>
<div class="hello-example">
    <a href="http://example.cn">Chinese (Traditional):</a>
    <span lang="zh-TW">世界您好！</span>
</div>

/* All spans with a "lang" attribute are bold */
span[lang] {font-weight:bold;}

/* All spans in Portuguese are green */
span[lang="pt"] {color:green;}

/* All spans in US English are blue  */
span[lang~="en-us"] {color: blue;}

/* Any span in Chinese is red, matches simplified (zh-CN) or traditional (zh-TW) */
span[lang|="zh"] {color: red;}

/* All internal links have a gold background */
a[href^="#"] {background-color:gold}

/* All links to urls ending in ".cn" are red */
a[href$=".cn"] {color: red;}

/* All links to with "example" in the url have a grey background */
a[href*="example"] {background-color: #CCCCCC;}