Fieldset不显示内联

Question

我有一个带有生日字段集的表单，我尝试了多个标记来强制字段在同一行中对齐。我试过显示：inline-block;排队;并且阻止没有运气。您将提供的任何帮助将不胜感激。谢谢！

这是我的字段集：

<fieldset class="birthday">
                 <label>Birthday</label>
                  <label class="month"> 
                  <select class="select-style" name="BirthMonth">
                  <option value="">Month</option>
                  <option  value="01">January</option>
                  <option value="02">February</option>
                  <option value="03" >March</option>
                  <option value="04">April</option>
                  <option value="05">May</option>
                  <option value="06">June</option>
                  <option value="07">July</option>
                  <option value="08">August</option>
                  <option value="09">September</option>
                  <option value="10">October</option>
                  <option value="11">November</option>
                  <option value="12" >December</option>
                  </label>
                 </select>    
                <label>Day<input class="birthday" maxlength="2" name="BirthDay"  placeholder="Day" required=""></label>
                <label>Year <input class="birthyear" maxlength="4" name="BirthYear" placeholder="Year" required=""></label>
              </fieldset>

这是我的css：

    .quoteform2 fieldset.birthday {display: inline-block; border:0px; padding:0px; margin:0px;}
    .quoteform2 label.month {width: 135px;}
.quoteform2 .select-style {
  -webkit-appearance: button;
  -webkit-border-radius: 2px;
  -webkit-box-shadow: 0px 1px 3px rgba(0, 0, 0, 0.1);
  -webkit-padding-end: 20px;
  -webkit-padding-start: 2px;
  -webkit-user-select: none;
  background-image: url(images/select-arrow.png), 
    -webkit-linear-gradient(#FAFAFA, #F4F4F4 40%, #E5E5E5);
  background-position: center right;
  background-repeat: no-repeat;
  border: 0px solid #FFF;
  color: #555;
  font-size: inherit;
  margin: 0;
  overflow: hidden;
  padding-top: 5px;
  padding-bottom: 5px;
  text-overflow: ellipsis;
  white-space: nowrap;}