css相关代码：

* {
    margin: 0;
    padding: 0;
}
/* 去掉所有ul,ol小圆点 */
ul,ol {
    list-style: none;
}
/* 去掉所有超级链接的下划线 */
a {
    text-decoration: none;
}
/* 使用继承性，给body标签设置字体 */
body {
    font: normal 14px/25px '微软雅黑';
}

/* header */
header {
    width: 100%;
    height: 80px;
    background-color: #07cbc9;
}
header .head {
    width: 1200px;
    height: 80px;
    margin: 0 auto;
    /* 清除浮动 */
    overflow: hidden;
}
header .head .logo {
    float: left;
    padding-top: 16px;
}
header .head .nav {
    float: right;
}
header .head .nav ul {
    width: 600px;
    height: 80px;
}
header .head .nav ul li {
    float: left;
    padding-left: 20px;
    /* 垂直居中-行高等于盒子高 */
    line-height: 80px;
}
header .head .nav ul li a {
    display: block;
    height: 80px;
    font-size: 16px;
    color: white;
}
/*  */
/*  */
/* banner */
.banner {
    width: 100%;
    height: 600px;
    position: relative;
}
.banner .banner_image {
    width: 100%;
    height: 600px;
}
.banner .banner_cover {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 600px;
    background-color: rgba(0,0,0,.5);
}
.banner .banner_form {
    width: 504px;
    position: absolute;
    top: 100px;
    left: 50%;
    margin-left: -252px;
    background: none;
    text-align: center;
}
.banner .banner_form>input {
    width: 498px;
    height: 40px;
    margin-bottom: 25px;


}
.banner .banner_form textarea {
    width: 498px;
    height: 110px;
    margin-bottom: 25px;

}
.banner .banner_form p .sub {
    width: 200px;
    height: 40px;

} 
.banner .banner_form input,textarea {
    border: 3px solid #808080;
    background: none;
    color: #808080;
}

/*  */
/* 内容区域 */
/* 分成左、中、右三大块，设置左右浮动，块内不用设置浮动 */
.content .about {
    padding-top: 30px;
    width: 1201px;
    margin: 0 auto;
    overflow: hidden;
}
/* ABOUT上半区域 */
.content .about .about_header {
    text-align: center;
    width: 500px;
    margin: 0 auto;
}
.content .about .about_header h2 {
    font-size: 32px;
}
.content .about .about_header .dividing_line {
    width: 60px;
    height: 3px;background-color: #07cbc9;
    margin: 10px auto;
}
.content .about .about_header p {
    display: block;   
    color: gray;
    font-size: 14px;
}
/* ABOUT下半区域 */
.content .about .about_details {
    position: relative;
    width: 1201px;
    height: 465px;
    padding-top: 30px;
}
.content .about .about_details h3 {
    font-size: 28px;
    font-weight: bold;
    line-height: 45px;
}
.content .about .about_details p {
    font-size: 18px;
}
/* 左下 */
.content .about .about_details .about_text {
    float: left;   
}
.content .about .about_details .about_text h3 {
    display: block;
    width: 270px;
}
.content .about .about_details .about_text .text {
    position: absolute;
    top: 50%;
    margin-top: -100px;
    width: 300px;
    padding: 20px;
    border: 1px solid gray;
    background-color: rgba(255,255,255,0.5);
}
.content .about .about_details .about_text .text a {
    display: block;
    width: 140px;
    height: 40px;
    background-color: black;
    color: white;
    line-height: 40px;
    text-align: center;
    margin-top: 30px;
}
/* 中间 */
.content .about .about_details .pic {
    width: 650px;
    height: 435px;
    float: left;
}
.content .about .about_details .pic img {
    width: 650px;
    height: 435px;
}
/* 右边 */
.content .about .about_details .data {
    width: 260px;
    float: right;
}
.content .about .about_details .data .stu,.faculty {
    width: 178px;
    border: 1px solid #07cbc9;
    text-align: center;
    padding: 40px;
}
.content .about .about_details .data .dividing_line {
    width: 60px;
    height: 3px;
    background-color: #07cbc9;
    margin: 10px auto;
}
.content .about .about_details .data .stu {
    margin-bottom: 30px;
}

/* 图文混排区 */
.content .images_passages {
    width: 100%;
    position: relative;
}
.content .images_passages .d {
    float: left;
    width: 25%;
    height: 380px;
    background-color: #07cbc9;
    position: relative;
}
/* 由于img是行内元素，默认存在间隙，可以给图片添加display:block;属性消除间隙 */
.content .images_passages .d h3 {
    padding-top: 20px;
    padding-left: 20px;
    font-size: 24px;
    color: white;
}
.content .images_passages .d img {
    display: block;
    width: 100%;
    height: 100%;
}
.content .images_passages .d .d_text {
    /* margin-top: 30px; */
    /* padding-left: 20px; */
    padding: 30px 20px;
    font-size: 16px;
    color: gray;
}
.content .images_passages .text_right::before {
    content: "";
    width: 0;
    height: 0;
    border: 20px solid transparent;
    border-right-color: #07cbc9;
    position: absolute;
    top: 170px;
    left: -40px;
}
.content .images_passages .text_left::after {
    content: "";
    width: 0;
    height: 0;
    border: 20px solid transparent;
    border-left-color: #07cbc9;
    position: absolute;
    top: 170px;
    right: -40px;
}
.content .images_passages .d .d_text p {
    margin-bottom: 20px;
}
.content .images_passages .d a {
    display: block;
    width: 138px;
    height: 40px;
    background-color: black;
    color: white;
    line-height: 40px;
    text-align: center;
    margin: 30px auto;
}
/*  */
/* gallery上半 */
.content .gallery {
    padding-top: 30px;
    width: 1201px;
    margin: 0 auto;
    overflow: hidden;
}
/* ABOUT上半区域 */
.content .gallery .gallery_header {
    text-align: center;
    width: 500px;
    margin: 0 auto;
}
.content .gallery .gallery_header h2 {
    font-size: 32px;
}
.content .gallery .gallery_header .dividing_line {
    width: 60px;
    height: 3px;background-color: #07cbc9;
    margin: 10px auto;
}
.content .gallery .gallery_header p {
    display: block;   
    color: gray;
    font-size: 14px;
}
/* gallery下半 */
.content .gallery .gallery_details {
    width: 1160px;
    height: 613px;
    padding: 20px;
    margin: 0 auto;
    overflow: hidden;
}
.content .gallery .gallery_details dl {
    float: left;
    width: 360px;
    height: 290px;
    margin-right: 40px;
    margin-bottom: 30px;
}
.content .gallery .gallery_details dl:nth-child(3n) {
    margin-right: 0;
}
.content .gallery .gallery_details dl:nth-child(n+4) {
    margin-bottom: 0;
}
.content .gallery .gallery_details dl dt img {
    display: block;
    width: 360px;
    height: 240px;
}
.content .gallery .gallery_details dl dd {
    display: block;
    width: 340px;
    height: 50px;
    line-height: 50px;
    color: white;
    background-color: black;
    padding-left:20px ;
}
footer {
    width: 100%;
    height: 80px;
    background-color: #07cbc9;
    text-align: center;
    line-height: 80px;
}

html相关代码：

​<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Career Bulider</title>
    <meta name="Description" content=" ">
    <meta name="Keywords" content=" ">
    <link rel="stylesheet" href="css/css.css">
</head>
<body>
    <!-- Header区域 -->
    <header>
        <div class="head">
            <!-- logo -->
            <div class="logo">
                <img src="images/logo.png" alt="">
            </div>
            <!-- nav -->
            <nav class="nav">
                <ul>
                    <li><a href="">HOME</a></li>
                    <li><a href="">ABOUT</a></li>
                    <li><a href="">GALLERY</a></li>
                    <li><a href="">FACULTY</a></li>
                    <li><a href="">EVENTS</a></li>
                    <li><a href="">CONTACT</a></li>
                </ul>
            </nav>
        </div>
    </header>
    <!-- Banner区域 -->
    <section class="banner">
        <!-- banner图片 -->
        <img  class="banner_image" src="images/banner3.jpg" alt="">
        <!-- banner遮罩层 -->
        <div class="banner_cover">banner遮罩层</div>
        <!-- banner表单 -->
        <form class="banner_form" action="" method="POST">
            <input type="text" placeholder="your Name">
            <input type="text" placeholder="your Phone">
            <input type="email" placeholder="your Email">
            <textarea placeholder="Write Your Comment Here"></textarea>
            <p><input class="sub" type="submit" value="SEND MESSAGE"></p>
        </form>
    </section>
    <!-- content区域 -->
    <section class="content">
        <!-- About区域 -->
        <section class="about">
            <!-- About区域标题和简短描述 -->
            <div class="about_header">
                <h2>ABOUT</h2>
                <div class="dividing_line"></div>
                <div>
                    <p>Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s.</p>
                </div>
            </div>
            <!-- About区域详细描述 -->
            <div class="about_details">
                <!-- 文字描述 -->
                <div class="about_text">
                    <h3>A WORD<br>ABOUT US</h3>
                    <div class="text">
                        <div>
                            <p>Praesent dignissim viverra est, sed bibendum ligula congue non. Sed ac nisl et felis gravida commodo? Suspendisse eget ullamcorper ipsum. Suspendisse diam amet.</p>
                        </div>
                        <div>
                            <a href="">EXPLORE</a> 
                        </div>
                    </div>
                </div>
                <!-- 图片描述 -->
                <div class="pic">
                    <img src="images/bb3.jpg" alt="">
                </div>
                <!-- 数据 -->
                <div class="data">
                    <div class="stu">
                        <h3>70000</h3>
                        <div class="dividing_line"></div>
                        <p>Sdudents</p>
                    </div>
                    <div class="faculty">
                        <h3>600</h3>
                        <div class="dividing_line"></div>
                        <p>Faculty</p>
                    </div>
                </div>
            </div>
        </section>
        <!-- 图文混排区域 -->
        <section class="images_passages">
            <!-- 图1 -->
            <div class="d">
                <img src="images/b1.jpg" alt="">
            </div>
            <!-- 文2 -->
            <div class="d db">
                <h3>Library</h3>
                <div class="d_text text_right">
                    <p>Lorem Ipsum is simply dummy text of the printing and typesetting industry
                    </p>
                    <p>Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book.</p>
                </div>
                <div>
                    <a href="">EXPLORE</a>
                </div>
            </div>
            <!-- 图3 -->
            <div class="d">
                <img src="images/b2.jpg" alt="">
            </div>
            <!-- 文4 -->
            <div class="d db">
                <h3>Computer Lab</h3>
                <div class="d_text text_right">
                    <p>Lorem Ipsum is simply dummy text of the printing and typesetting industry
                    </p>
                    <p>Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book.</p>
                </div>
                <div>
                    <a href="">EXPLORE</a>
                </div>
            </div>
            <!-- 文5 -->
            <div class="d da">
                <h3>Conference Hall</h3>
                <div class="d_text text_left">
                    <p>Lorem Ipsum is simply dummy text of the printing and typesetting industry
                    </p>
                    <p>Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book.</p>
                </div>
                <div>
                    <a href="">EXPLORE</a>
                </div>
            </div>
            <!-- 图6 -->
            <div class="d">
                <img src="images/b3.jpg" alt="">
            </div>
            <!-- 文7 -->
            <div class="d da">
                <h3>Play Ground</h3>
                <div class="d_text text_left">
                    <p>Lorem Ipsum is simply dummy text of the printing and typesetting industry
                    </p>
                    <p>Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book.</p>
                </div>
                <div>
                    <a href="">EXPLORE</a>
                </div>
            </div>
            <!-- 图8 -->
            <div class="d">
                <img src="images/b4.jpg" alt="">
            </div>
        </section>

        <!-- Gallery区域 -->
        <section class="gallery">
            <!-- Gallery区域简短描述 -->
            <div class="gallery_header">
                <h2>GALLERY</h2>
                <div class="dividing_line"></div>
                <div>
                    <p>Lorem Ipsum is simply dummy text of the printing and typesetting industry.Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book.</p>
                </div>
            </div>
            <!-- Gallery区域详细信息 -->
            <div class="gallery_details">
                <dl>
                    <dt>
                        <img src="images/03-01.jpg" alt="">
                    </dt>
                    <dd>Science Lab</dd>
                </dl>
                <dl>
                    <dt>
                        <img src="images/03-02.jpg" alt="">
                    </dt>
                    <dd>Indoor Stadium</dd>
                </dl>
                <dl>
                    <dt>
                        <img src="images/03-03.jpg" alt="">
                    </dt>
                    <dd>Transportation</dd>
                </dl>
                <dl>
                    <dt>
                        <img src="images/03-04.jpg" alt="">
                    </dt>
                    <dd>Kids Room</dd>
                </dl>
                <dl>
                    <dt>
                        <img src="images/03-05.jpg" alt="">
                    </dt>
                    <dd>Meditation Classes</dd>
                </dl>
                <dl>
                    <dt>
                        <img src="images/03-06.jpg" alt="">
                    </dt>
                    <dd>Kids Play Ground</dd>
                </dl>
            </div>
        </section>
    </section>
    <!-- Footer区域 -->
    <footer>
        <p>&copy;2016 imooc.com 京ICP备13046642号</p>
    </footer>
</body>
</html>