下拉列表怎么没效果呢，还有箭头怎么加，这个下拉用select标签能做吗

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                <div class="header_logo">高铁客户服务中心<span> | </span><span>客户服务</span></div>
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            <h2>您现在的位置：<span>客运首页 > 注册</span></h2>
            <form action="">
                <h2>账户信息</h2>
                <P><span>*</span><span>用 户 名：</span><input type="text" placeholder="用户名设置成功后不可更改"><span class="prompt"></span></P>
 
                <P><span>*</span><span>登录密码：</span><input type="password" placeholder="6-20位字母、数字或符号"><span class="prompt"></span></P>
 
                <P><span>*</span><span>确认密码：</span><input type="password" placeholder="再次输入您的登录密码"><span class="prompt"></span></P>
 
                <P><span>*</span><span>姓名：</span><input type="text" placeholder="请输入姓名"><span><a href="#">姓名填写规则</a></span></P>
 
                <P><span>*</span><span>证件类型：</span><select name="credit" id="credit"><option value="二代身份证">二代身份证</option></select><span class="prompt"></span></P>
 
                <P><span>*</span><span>证件号码：</span><input type="text" placeholder="请输入您的证件号码"><span class="prompt"></span></P>
 
                <P><span></span><span>邮   箱：</span><input type="email" placeholder="请正确填写邮箱地址"><span class="prompt"></span></P>
 
                <P><span>*</span><span>手机号码：</span><input type="text" placeholder="请输入您的手机号码"><span class="prompt"></span></P>
 
                <P><span>*</span><span>旅客类型：</span><select name="people" id="people"><option value="成人">成人</option></select><span class="prompt"></span></P>
 
                <p><input type="checkbox">我已阅读并同意遵守    <a href="">《中国铁路客户服务中心网站服务条款》</a></p>
 
                <input type="submit" id="sub" value="下一步">
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*{
    margin:0;
    padding: 0;
}
a{
    text-decoration: none;
    color: #000;
}
 
.registry{
    width: 100%;
    height:120px ;
}
/* 导航栏 */
header{
    position: relative;
    background: #efefef;
}
.header_wrap{ 
    position: relative;
    width: 1260px;
    height: 120px;
    margin: 0 auto;   
}
.header_logo{
    position: absolute;
    display: inline-block;
    width: 460px;
    height: 100px;
    background: url(../img/logo.png) left center no-repeat;
    line-height: 100px;
    font-size: 24px;
    text-indent: 120px;
    top:10px;
}
.header_logo>span:first-child{
    font-size:28px;
    font-weight: bolder;
}
.header_logo>span:last-child{
    font-size:20px;
    color:#66667b;
}
.header_logo>a:nth-child(2),.header_logo>a:nth-child(2){
    color:#fb7403;
}
/* 导航条 */
nav{
    position: absolute;
    right:100px;
    font-size: 16px;
    line-height: 120px;
}
nav>a:nth-child(2),nav>a:nth-child(4){
    color:#fb7403;
}
.menu{
    float: right;
}
.menu-list{
    display: none;
}
.menu:hover{
    display: block;
}
 
.phone{
    position: absolute;
    right:0px;
    display: inline-block;
    width: 76px;
    height: 24px;
    margin: 0 atuo;
    background: url(../img/未标题-1.png) left  no-repeat;
    background-size:auto 100%;
    top:48px;
    text-indent: 24px;
}