<!--banner-->
    <div class="banner">
        <banner>
            <img class="img-banner" src="images/banner3.jpg">
            <div class="cover"></div>
            <div class="update">
                <form class="banner-form">
                    <input class="banner-form-input bf" type="text" placeholder="your Name">
                    <input class="banner-form-input bf" type="text" placeholder="your Phone">
                    <input class="banner-form-input bf" type="email" placeholder="your E-mail">
                    <textarea class="banner-form-textarea bf"  cols="30" rows="10" placeholder="your Comment"></textarea><br>
                    <button class="banner-form-button " type="submit">SEND MESSAGE</button>
                </form>
            </div>
        </banner>
    </div>

​*{
    margin: 0;
    padding: 0;
}
ul li{
    list-style: none;
}
a{
    text-decoration: none;
}
header{
    width: 100%;
    height: 80px;
    background-color: #07cbc9;
}
header .header{
    width: 1200px;
    height: 80px;
    margin: 0 auto;
}
header .header .logo{
    width: 600px;
    height: 48px;
    float: left;
    margin: 16px 0;
}
header .header nav{
    width: 600px;
    height: 80px;
    float: right;
}
header .header nav ul{
    float: left;
}
header .header nav ul li{
    width: 100px;
    height: 80px;
    float: left;
    margin-right: 20px;
    line-height: 80px;
}
header .header nav ul li a{
    font-size: 16px;
    color: rgba(255,255,255,0.9);
}
.content .banner{
    position: relative;
    width: 1920px;
    height: 600px;
}
.content .banner .img-banner{
    width: 100%;
    height: 600px;
}
.content .banner .cover{
    width: 100%;
    height: 600px;
    position: absolute;
    left: 0;
    top: 0;
    background:rgba(0, 0, 0, 0.5)
}
.content .banner .banner-form{
    position: absolute;
    top: 100px;
    left: 50%;
    background: none;
    float: left;
    margin-left: -257px;
    text-align:center;
    color: #808080;
}
.content .banner .banner-form .bf{
    display: block;
    margin-bottom: 10px;
    background: none;
    border: solid #808080;
}
.content .banner .banner-form .banner-form-input{
    width: 504px;
    height: 40px;
}
.content .banner .banner-form .banner-form-textarea{
    width: 504px;
    height: 110px;
}
.content .banner .banner-form .banner-form-button{
    background: none;
    width: 200px;
    height: 40px;
    color: #808080;
}