我想包括owencm的评论,让人们绊倒这个问题,因为我发现它很优雅：

CSS

input.holo[type='text'] {
    /* You can set width to whatever you like */
    width: 200px;
    font-family: "Roboto","Droid Sans",sans-serif;
    font-size: 16px;
    margin: 0;
    padding: 8px 8px 6px 8px;
    position: relative;
    display: block;
    outline: none;
    border: none;
    background: bottom left linear-gradient(#a9a9a9,#a9a9a9) no-repeat,bottom center linear-gradient(#a9a9a9,#a9a9a9) repeat-x,bottom right linear-gradient(#a9a9a9,#a9a9a9) no-repeat;
    background-size: 1px 6px,1px 1px,1px 6px;
}
input.holo[type='text']:hover,input.holo[type='text']:focus {
    background: bottom left linear-gradient(#0099cc,#0099cc) no-repeat,bottom center linear-gradient(#0099cc,#0099cc) repeat-x,bottom right linear-gradient(#0099cc,#0099cc) no-repeat;
    background-size: 1px 6px,1px 6px; 
}

HTML

<input type='text' class='holo'/>

的jsfiddle
http://jsfiddle.net/QKm37/

原始解决方案

<span style="
  border-bottom: solid 1px cyan;
  border-left: solid 1px cyan;
  margin: 20px;
  border-right: solid 1px cyan;
  overflow: visible;
  max-height: 0.2em;
  display: inline-block;
  padding: 2px;
">
<input type="text" style="
  outline: none;
  border: none;
  background: transparent;
  display: inline-block;
  position: relative;
  bottom: 0.8em;
">
</span>