对中单选按钮(柔性盒？)

Question

我正试图将一些单选按钮水平和垂直地居中：http://jsfiddle.net/yxxd0cht/

我正在考虑使用柔性盒之类的东西，但我没能让它起作用。

CSS：

.costs
{
font-family: Arial, sans-serif;
background-color:#FFBC02;
color:white;
padding: 5px 12px;
margin-left:5px;
font-size: 1.05em;
}

input[type=radio]
{
display:none;
}

HTML：

<div id="green">
<fieldset id="costs">
                <legend>Costs: </legend>
                <input id="free" name="costs" type="radio" value="free">
                <label class="costs" for="free">Free</label>

                <input id="chargeable" name="costs" type="radio" value="chargeable">
                <label class="costs" for="chargeable">Chargeable</label>

                <input id="mixed" name="costs" type="radio" value="mixed" checked>
                <label  class="costs" for="mixed">Mixed</label>
                </fieldset>
</div>

Answer 1

如果您开放使用flexbox，并且使用HTML5语法，那么我假设您的浏览器需求也允许您使用另一种策略。这是我最喜欢的方法，在未知维度的容器中精确地对齐一个未知维度的元素。

注意，我也清理了标记--因为您没有使用任何需要您通过类或ID精确标识项的JavaScript，您真正关心的唯一ID就是#green div。使用元素级选择器可以轻松地解决其余的元素，这有助于您避免过度指定样式，并使长期维护更容易。

​

#green {
  background-color: green;
  height: 200px;
  /* Make this the positioning parent for fieldset */
  position: relative;
}
#green label {
  font-family: Arial, sans-serif;
  background-color: #FFBC02;
  color: white;
  padding: 5px 12px;
  margin-left: 5px;
  font-size: 1.05em;
}
#green input[type=radio] {
  display: none;
}
#green input[type=radio]:checked + label {
  background-color: lightgreen;
}
#green fieldset {
  /* Border added for visualization */
  border: 1px solid red;
  /* Position absolute will position relative to first
  non-static ancestor (in this case, #green) */
  position: absolute;
  /* Positions fieldset's top/left corner exactly in the
  center of #green */
  top: 50%;
  left: 50%;
  /* Translate's percentages are based on dimensions of 
  the element, not the width of the container, like 
  CSS % units. */
  transform: translate(-50%, -50%);
}

<!-- Removed unnecessary classes & IDs throughout.
The elements are easily addressible in CSS styles using 
#green as the parent. -->
<div id="green">
  <fieldset>
    <legend>Costs:</legend>
    <input id="free" name="costs" type="radio" value="free">
    <label for="free">Free</label>

    <input id="chargeable" name="costs" type="radio" value="chargeable">
    <label for="chargeable">Chargeable</label>

    <input id="mixed" name="costs" type="radio" value="mixed" checked>
    <label for="mixed">Mixed</label>
  </fieldset>
</div>

​