auth-google-link呈现为锚标记，默认情况下呈现为text-decoration：将下划线设置为该属性。

您可以删除text-decoration，它应该可以正常工作。

您可以通过删除HTML代码中的换行符来删除文本中不需要的空格或***下划线***... HTML代码中的换行符正在创建此下划线。
代替

<a id='auth-google-link' href="/auth/google">
   <img id='auth-google-image' src='data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHhtbG5zOnhsaW5rPSJodHRw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%0D%0Ac3ZnPg==' />
</a>
<p id="auth-google-text">
   hi
</p>

删除A***标记内的换行符***...

<a id='auth-google-link' href="/auth/google"><img id='auth-google-image' src='data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHhtbG5zOnhsaW5rPSJodHRw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%0D%0Ac3ZnPg==' /></a>
       <p id="auth-google-text">hi</p>

https://jsfiddle.net/a85xbgfq/

将display: inline-block添加到#auth-google-link：

#auth-google-link {
  display: inline-block;
}

另请参见CSS - Underline text but ignore the spaces

因为您使用了锚标记。请使用text-decoration: none;属性删除锚标记中的下划线。

a{
text-decoration: none;}