HTML核心+CSS基础（练习）

学习语言练习是必不可少，重中之重的，这一周我进行了常规流，浮动，定位以及表单元素的练习

下面就让我们一起看看这周的分享吧！

一常规流练习

1. 在reset中书写通用的样式

在index中写自己设计的样式

用之前在head中加link引用css文件

2. 当设计稿的宽度太宽时要和设计师沟通，否则可能会出现滚动条

3. 常规流块盒且宽度固定时，用margin设置居中

4. 文章的头部标题，可以用header语义化元素

5. div元素出现频率很高，一般不使用元素选择器

6. 有5个section元素其中有五个标题（标题内容是啥）后面有三段随机文字

7. min-width: 1000px;/*设置最小宽度以免缩小网页时不好看*/

设置前

设置后

8. 设置整个网页的背景颜色设置在body中

9. padding上下内边距，到内容之间的距离

margin上下外边距，到边框

10. 文字的行高是可以继承的，所以若全局的行高一致的话可以在body元素中设置

11. 常规流块盒上下外边距（margin）会出现合并，可以通过设置父元素的内边距padding来实现!

12. 12. dashed可以设置虚线边框

HTML代码

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="stylesheet" href="css/reset.css">
    <link rel="stylesheet" href="css/index2.css">
<body>
    <article class="neirong">
        <header>
            <h1>高等数学答案</h1>
            <div class="yi">
                原文地址是:<a href="https://www.baidu.com">百度</a>
            </div>
        </header>
        <div class="duan">
            <p class="yi">
                <h2 class="er">章节1</h2>
                <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Nam, repellendus ut natus minus voluptates doloremque quae quasi. Modi inventore veritatis vero quisquam aut. Odio velit minus est a, delectus sit.</p>
            </p>
            <p class="yi">
                <h2>章节2</h2>
                <p>Lorem ipsum dolor sit amet consectetur, adipisicing elit. Cum, dolor dolorum. Cumque minima, doloribus et provident amet debitis quos similique mollitia iure pariatur optio, accusantium eum recusandae. Placeat, quae amet.</p>
            </p>
            <p class="yi">
                <h2>章节3</h2>
                <p>Lorem ipsum dolor sit amet consectetur adipisicing elit. Tempora rerum corrupti temporibus nobis nulla. Molestiae porro culpa eius minus accusantium esse consectetur sequi, beatae doloribus, est excepturi. Aliquid, alias incidunt.</p>
            </p>
            <p class="yi">
                <h2>章节4</h2>
                <p>Lorem ipsum, dolor sit amet consectetur adipisicing elit. Nam facilis soluta explicabo harum vero commodi, veritatis voluptatum voluptatibus repellat? Ullam, laboriosam consectetur minus illo sunt nesciunt quaerat suscipit id sed
                </p>
            </p>
            <p class="yi">
                <h2>章节5</h2>
                <p>Lorem, ipsum dolor sit amet consectetur adipisicing elit. Maxime voluptatibus quo aliquid unde modi est quae quos, illo ipsam cupiditate reiciendis fuga praesentium id at minus ex ipsum harum repellat.</p>
            </p>
            <p class="yi">
                <h2>章节6</h2>
                <p>Lorem ipsum dolor sit amet consectetur adipisicing elit. Sit laudantium iusto optio, libero minus at assumenda sint accusamus aliquam fuga facere molestiae? Dolorum molestiae aut ad eum iste blanditiis rerum.</p>
            </p>
        </div>

    </article>
</body>
</html>

CSS代码

body{
    background: #4d4a40;
    line-height: 2;

}
.neirong{
   
    background: #fff;
    width: 90%; 
    margin: 10px auto;
    padding: 30px 0;
}
header{
    background: #0bcf9e;
    text-align: center; 
    margin:  0 -20px;
    color: #fff;
    font-weight: bold;
    font-size: 30px;
    border:3px solid #4d4a40;
}
header .yi{
    color: #4d4a40;
    font-weight:normal;
    font-size: 15px;
}
.neirong .duan h2{
    font-size: 30px;
    border-bottom:3px dashed ;
    border-top:3px dashed ;
    margin: 5px 0;
    font-weight: bold;
}
.neirong .duan .yi{
    width: 90%;
    margin: 0 auto;
}

效果图

二浮动练习

# 导航菜单

1. ul>li*导航菜单的个数>a>导航菜单的内容

2. nav元素表示导航菜单

<nav>

a*导航菜单的个数>导航菜单的内容

</nav>

# 设置行高

text-align:center ; /*水平居中*/

line-height: 60px; /*垂直居中 line-height=height（行高）*/

# 鼠标移入时变成什么颜色

.main .nav a :hover

{/*鼠标在其上面时为什么颜色*/

color: #fff;

}

# 鼠标位于当前页面时显示的是什么

.main .nav a.select{

color: #ef4238;/*鼠标位于当前页面时显示的是什么*/

}

# 居中

水平方向上

margin: 0 auto;

# 解决高度坍塌

某一元素设置了浮动之后，找其父元素看其父元素有没有固定高度，有则不会发生高度坍塌，没有则需给其父元素加上clearfix

.clearfix::after{

content:"" ;

display: block;

clear: both;

}

# 引用元素时要用空格隔开

# 将边框设置为圆的

/*css3圆角边框*/

border-radius: 15px;

# 重复电影类型速写

div.movie-item*30>(图片)+(名字)+(评分)来生成

# nth-child() 伪类选择器，选择括号里面的数据进行样式的改变

.main .container .movies .movie-item:nth-child(6n){

样式

}

# 文字多时显示时有省略号可以用

white-space: nowrap;

overflow: hidden;

text-overflow: ellipsis;

padding: 0 2px;

text-align: center;

# 文字为斜体

font-style: italic;

# 让第一个字变大

.main .container .movies .movie-item .score::first-letter{

font-size: 1.5em;

}

# first-letter元素选择器

可选中第一个元素

# 将某一元素浮动之后就加一个clearfix防止高度坍塌

# 浮动后的元素是块盒，不用再设置边框，直接改变边框弧度就可以实现

HTML代码

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>猫眼电影</title>
    <link rel="stylesheet" href="css/movie2.css">
    <link rel="stylesheet" href="css/reset.css">
</head>
<body>
    <div class="main">
    
        <nav class="toulan clearfix">
            <a href="" class="select">正在热映</a>
            <a href="">热播电影</a>
            <a href="">经典影片</a>
        </nav>
      <div class="container clearfix">
        <div class="choose">
            <div class="choose-item clearfix">
                <div class="left">类型：</div>
                <div class="right">
                    <ul>
                        <li class="select">Lorem.</li>
                        <li>Voluptates?</li>
                        <li>Aliquid.</li>
                        <li>A.</li>
                        <li>At.</li>
                        <li>Error!</li>
                        <li>Ex?</li>
                        <li>Ducimus.</li>
                        <li>Doloremque.</li>
                        <li>Itaque!</li>
                        <li>Lorem.</li>
                        <li>Fugit!</li>
                        <li>Autem.</li>
                        <li>Accusantium.</li>
                        <li>Voluptatem!</li>
                        <li>Cumque?</li>
                        <li>Dolorum!</li>
                        <li>Aliquam?</li>
                    </ul>
                </div>
            </div>
            <div class="choose-item clearfix">
                <div class="left">区域：</div>
                <div class="right">
                    <ul>
                        <li class="select">Lorem.</li>
                        <li>Voluptates?</li>
                        <li>Aliquid.</li>
                        <li>A.</li>
                        <li>At.</li>
                        <li>Error!</li>
                        <li>Ex?</li>
                        <li>Ducimus.</li>
                        <li>Doloremque.</li>
                        <li>Itaque!</li>
                        <li>Lorem.</li>
                        <li>Earum!</li>
                        <li>Hic.</li>
                        <li>Nihil.</li>
                        <li>Voluptates!</li>
                        <li>Labore.</li>
                        <li>Possimus!</li>
                        <li>Dolores?</li>
                    </ul>
                </div>
            </div>
            <div class="choose-item clearfix">
                <div class="left">年代：</div>
                <div class="right">
                    <ul>
                        <li class="select">Lorem.</li>
                        <li>Voluptates?</li>
                        <li>Aliquid.</li>
                        <li>A.</li>
                        <li>At.</li>
                        <li>Error!</li>
                        <li>Ex?</li>
                        <li>Ducimus.</li>
                        <li>Doloremque.</li>
                        <li>Itaque!</li>
                        <li>Lorem.</li>
                        <li>Minima?</li>
                        <li>Odit.</li>
                        <li>Porro!</li>
                        <li>Mollitia?</li>
                        <li>Saepe.</li>
                        <li>Veritatis.</li>
                        <li>Explicabo?</li>
                    </ul>
                </div>
            </div>
        </div>
        
        <div class="poster">
            <div class="img">
                <a href="">
                    <img src="img/fb7386920fa3399257b53575e4a7e61da8cd7.jpg" alt="">
                </a>
            </div>
            <div class="name">
                <a href="">宋威龙</a>
                
            </div>
            <div class="score">
                9.6
            </div>
        </div>
        <div class="poster">
            <div class="img">
                <a href="">
                    <img src="img/fb7386920fa3399257b53575e4a7e61da8cd7.jpg" alt="">
                </a>
            </div>
            <div class="name">
                <a href="">宋威龙</a>
                
            </div>
            <div class="score">
                9.6
            </div>
        </div>
        <div class="poster">
            <div class="img">
                <a href="">
                    <img src="img/fb7386920fa3399257b53575e4a7e61da8cd7.jpg" alt="">
                </a>
            </div>
            <div class="name">
                <a href="">宋威龙</a>
                
            </div>
            <div class="score">
                9.6
            </div>
        </div>
        <div class="poster">
            <div class="img">
                <a href="">
                    <img src="img/fb7386920fa3399257b53575e4a7e61da8cd7.jpg" alt="">
                </a>
            </div>
            <div class="name">
                <a href="">宋威龙</a>
                
            </div>
            <div class="score">
                9.6
            </div>
        </div>
        <div class="poster">
            <div class="img">
                <a href="">
                    <img src="img/fb7386920fa3399257b53575e4a7e61da8cd7.jpg" alt="">
                </a>
            </div>
            <div class="name">
                <a href="">宋威龙</a>
                
            </div>
            <div class="score">
                9.6
            </div>
        </div>
        <div class="poster">
            <div class="img">
                <a href="">
                    <img src="img/fb7386920fa3399257b53575e4a7e61da8cd7.jpg" alt="">
                </a>
            </div>
            <div class="name">
                <a href="">宋威龙</a>
                
            </div>
            <div class="score">
                9.6
            </div>
        </div>
        <div class="poster">
            <div class="img">
                <a href="">
                    <img src="img/fb7386920fa3399257b53575e4a7e61da8cd7.jpg" alt="">
                </a>
            </div>
            <div class="name">
                <a href="">宋威龙</a>
                
            </div>
            <div class="score">
                9.6
            </div>
        </div>
        <div class="poster">
            <div class="img">
                <a href="">
                    <img src="img/fb7386920fa3399257b53575e4a7e61da8cd7.jpg" alt="">
                </a>
            </div>
            <div class="name">
                <a href="">宋威龙</a>
                
            </div>
            <div class="score">
                9.6
            </div>
        </div>
        <div class="poster">
            <div class="img">
                <a href="">
                    <img src="img/fb7386920fa3399257b53575e4a7e61da8cd7.jpg" alt="">
                </a>
            </div>
            <div class="name">
                <a href="">宋威龙</a>
                
            </div>
            <div class="score">
                9.6
            </div>
        </div>
        <div class="poster">
            <div class="img">
                <a href="">
                    <img src="img/fb7386920fa3399257b53575e4a7e61da8cd7.jpg" alt="">
                </a>
            </div>
            <div class="name">
                <a href="">宋威龙</a>
                
            </div>
            <div class="score">
                9.6
            </div>
        </div>
        <div class="poster">
            <div class="img">
                <a href="">
                    <img src="img/fb7386920fa3399257b53575e4a7e61da8cd7.jpg" alt="">
                </a>
            </div>
            <div class="name">
                <a href="">宋威龙</a>
                
            </div>
            <div class="score">
                9.6
            </div>
        </div>
        <div class="poster">
            <div class="img">
                <a href="">
                    <img src="img/fb7386920fa3399257b53575e4a7e61da8cd7.jpg" alt="">
                </a>
            </div>
            <div class="name">
                <a href="">宋威龙</a>
                
            </div>
            <div class="score">
                9.6
            </div>
        </div>
        <div class="poster">
            <div class="img">
                <a href="">
                    <img src="img/fb7386920fa3399257b53575e4a7e61da8cd7.jpg" alt="">
                </a>
            </div>
            <div class="name">
                <a href="">宋威龙</a>
                
            </div>
            <div class="score">
                9.6
            </div>
        </div>
        <div class="poster">
            <div class="img">
                <a href="">
                    <img src="img/fb7386920fa3399257b53575e4a7e61da8cd7.jpg" alt="">
                </a>
            </div>
            <div class="name">
                <a href="">宋威龙</a>
                
            </div>
            <div class="score">
                9.6
            </div>
        </div>
        <div class="poster">
            <div class="img">
                <a href="">
                    <img src="img/fb7386920fa3399257b53575e4a7e61da8cd7.jpg" alt="">
                </a>
            </div>
            <div class="name">
                <a href="">宋威龙</a>
                
            </div>
            <div class="score">
                9.6
            </div>
        </div>
        <div class="poster">
            <div class="img">
                <a href="">
                    <img src="img/fb7386920fa3399257b53575e4a7e61da8cd7.jpg" alt="">
                </a>
            </div>
            <div class="name">
                <a href="">lalalalallalallalla宋威龙天袭位</a>
                
            </div>
            <div class="score">
                9.6
            </div>
        </div>
        <div class="poster">
            <div class="img">
                <a href="">
                    <img src="img/fb7386920fa3399257b53575e4a7e61da8cd7.jpg" alt="">
                </a>
            </div>
            <div class="name">
                <a href="">宋威龙</a>
                
            </div>
            <div class="score">
                9.6
            </div>
        </div>
        
       

        </div>
      </div> 
</div>
</body>
</html>

CSS代码

.clearfix::after{
    content: "";
    display: block;
    clear: both;
}
body{
    line-height: 1.5;
    color: #333;
}
.main .toulan{
    height: 60px;
    background-color: #333;
    color: #ccc;
   text-align: center;
   font-size: 16px;
   line-height: 60px;
}

.main .toulan a{
    margin: 0 30px;
}
.main .toulan a:hover{
    color: white;
}
.main .toulan a.select{/*此处的a不能省去，否则上面一个选择器
    的等级会高于目前的，鼠标移上后会变成白色*/
    color: red;
}

.main .container{
    width: 1120px;
    margin: 0 auto;

}
.main .container .choose-item{
    border:1px solid #ccc;
   height: 80px;
    position: relative;
    margin: 10px 0;
    line-height: 30px;
    
} 
.main .container .choose-item .left{
    float: left;
    padding: 5px 10px;
}
.main .container .choose-item .right{
    position: absolute;
    left: 50px;
    
}
.main .container .choose-item .right li{
    float:left;
    margin: 5px 20px;
   /* margin: 0 9px;一个元素左右的像素各九个，即左右之间的距离
    padding: 0 6px;
     */
    
}
.main .container .choose-item .select{
    background: red;
    border-radius: 10px;
    
    
}
.main .container .poster{
    float: left;
    margin:10px 14px ;
   width: 160px;
}
.main .container .poster:nth-child(6n){
    margin-right: 0;
}
.main .container .poster .img{
   width: 160px;
   height: 220px;
}
.main .container .poster .name{
    text-align: center;
    padding: 5px 0;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;

}
.main .container .poster .score{
    text-align: center;
    color: #e98622;
    font-style: italic;
    padding: 5px 0;
}
.main .container .poster .score::first-letter{
    font-size: large;

}

效果图

三定位练习

二级菜单

1. 只要使用了浮动记得给其父元素加clearfix

.clearfix::after{

content: "";

display: block;

clear: both;

}

2. 二级菜单是某个菜单的一个子菜单，写在它对应的li中就好了

<li><a href="">Est.</a></li>

<li><a href="">Aut!</a></li>

<li>

<a href="">客户服务</a> 子菜单

<div class="submenu">

<ul>

<li>Lorem.</li>

<li>Tempora!</li>

</li>

3. 浮动元素高度，宽度是auto时，表示高度，宽度适应内容，内容较多时就会把宽度撑开

4. .header .topnav>li topnav后面加了>li表示支只对li元素进行样式设置

5. 先四个方向全部设置边框最后去掉下边框，得到三周边框

border: 2px solid #ccc;

border-bottom: none;

6. 想要加了边框后不改变盒子的尺寸，用 box-sizing: border-box;

7. 行高固定，加了边框后，框内的内容会往下移，为了解决此问题，可以设置line-height 调试到合适的行高使得文字不再移动

8. 实现鼠标点上去显示，移开时隐藏

/*不生成盒子,若一个元素没有生成盒子的话，元素是不显示的*/

display: none;

/*使其移上时显示*/

.header .topnav>li:hover.submenu{

display: block;

}

9. 若想要固定菜单可以设置,就可以让菜单固定在网页上，不随页面滑动而移动

position: fixed;

width: 100%;

left: 0;

top: 0;

10. 点击谁出现下一级菜单，就在谁的后面加：hover

.header .topnav>li:hover .submenu

点击 li 时显示submenu内容

三级菜单练习

HTML代码

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="stylesheet" href="./考/css/cai.css">
    <link rel="stylesheet" href="./考/css/reset.css">

</head>
<body>
    <div class="neirong">
       <ul class="yi clearfix">
        <li><a href="">Lorem.</a></li>
        <li><a href="">Perspiciatis?</a></li>
        <li>
            <a href="" class="yiji">植物</a>
            <div class="er">
            <ul class="erji clearfix">
                <li><a href="">Lorem.</a></li>
                <li><a href="">Reiciendis?</a></li>
                <li>
                    <a href="">蔬菜</a>
                    <div class="san clearfix">
                        <ul>
                            <li><a href="">Lorem.</a></li>
                            <li><a href="">Laboriosam?</a></li>
                            <li><a href="">黄瓜</a></li>
                            <li><a href="">Delectus!</a></li>
                            <li><a href="">Asperiores?</a></li>
                        </ul>
                    </div>
                </li>
                <li><a href="">Amet?</a></li>
                <li><a href="">Incidunt!</a></li>
                <li><a href="">Consequatur!</a></li>
                <li><a href="">Provident.</a></li>
                <li><a href="">Repudiandae.</a></li>
                <li><a href="">Quaerat.</a></li>
                <li><a href="">A?</a></li>
            </ul></div>
        </li>
        <li><a href="">Quae.</a></li>
        <li><a href="">Quasi?</a></li>
        <li><a href="">Dicta!</a></li>
        <li><a href="">Doloribus.</a></li>
        <li><a href="">Perspiciatis.</a></li>
        <li><a href="">Consequuntur.</a></li>
        <li><a href="">Quia.</a></li>
       </ul>
    </div>
    
</body>
</html>

CSS代码

.clearfix::after{
    content: "";
    display: block;
    clear: both;
}

.neirong {
    background: #ccc;
    position: fixed;
    width: 100%;
    height: 50px;
}
.neirong .yi>li{
    float: left;
    width: 120px;
    height: 50px;
    color: #fff;
    line-height: 50px;
    text-align: center;
    margin: 0 10px; 
    position: relative;
}
.neirong .yi>li:hover{
    background: #888;
    color: #159898;
}

.neirong .yi>li .er{
   
    width: 120px;
    background: #ccc;
border: 1px solid #888;
    box-sizing: border-box;
    display: none;
    line-height: 1.5;
    text-align: center;
}    

.neirong .yi>li .er li:hover{
    background: #888;
    color: #159898;
}
.neirong .yi>li:hover .er{
    display: block;
}

.neirong .yi>li .er .san{
    width: 120px;
    background: #ccc;
border: 1px solid #888;
    box-sizing: border-box;
    display: none;
    line-height: 1.5;
    text-align: center;
}
.neirong .yi>li .er li:hover .san{
    display: block;
    position: absolute;
    left: 120px;
    top: 50px;
}

效果图

2 弹出层

1. 透明效果

每个颜色都具有透明通道，0 ~ 1，1不透明，0完全透明

（1）.rgba(红，绿，蓝，alpha)

（2）.hex: #红绿蓝透

改变透明度可以实现蒙层

2. 鼠标变为一个小手，用cursor: pointer;

3. 设置完定位后，必须设置left: right: top: bottom: 的值

4. 蒙层是在背景图上面重新设置一个div，蒙在背景图上面

HTML代码

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="stylesheet" href="css/reset.css">
    <link rel="stylesheet" href="css/弹出层.css">
</head>
<body>
    <div class="main">
        <img src="./img/宋威龙.webp" alt="">
    </div>

    <!--遮罩层-->
    <div class="modal">
        <div class=" container">
            <div class="main">
                Lorem ipsum dolor sit amet, consectetur adipisicing elit. Illum dolorum saepe at quis. Dignissimos, nobis. Deleniti quas, quasi reprehenderit blanditiis sed quidem non ea repellendus suscipit aperiam dolore quae architecto?
            </div>
            <div class="close">
                X
            </div>
        </div>
    </div>
</body>
</html>

CSS代码

.main img{
    width: 100%;
}
/*用一个罩子把视口盛满*/
.modal{
    position: fixed;
    width: 100%;/*包含快为视口*/
    height: 100%;
    left: 0;
    top: 0;
    background:rgba(0, 0, 0, .5)
    


}
.modal .container{
    width: 400px;
    height: 512px;
    background: #fff;
    position: absolute;
    left: 0;
    right: 0;
    top: 0;
    bottom: 0;
    margin: auto;
    box-sizing: border-box;
    padding: 1em;
    border-radius: 6px;
}
.modal .container .close{
    width: 30px;
    height: 30px;
    background: red;
    border-radius: 50%;
    color: #fff;
    text-align: center;
    line-height: 30px;
    position: absolute;
    top: -15px;
    right: -15px;
border: 2px solid #ccc;
cursor: pointer;
}

效果图

3 轮播图

1. 图片显示一张，但是其后面可能有很多张

2. 蒙层使用绝对定位还是相对定位取决于蒙层是蒙上网页的一部分（绝对定位），还是蒙上整个视口（固定定位）

3. 溢出那个div就给那个div设置 overflow: hidden;隐藏溢出的东西

HTML代码

 <!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="stylesheet" href="css/reset.css">
    <link rel="stylesheet" href="css/轮播图.css">
</head>
<body>
    <div class="banner">
        <div class="imgs">
           
          <a href=""><img src=" ./img/1.jpg" alt=""></a>
          <a href=""><img src="./img/2.jpg" alt=""></a>
          <a href=""><img src="./img/3.jpg" alt=""></a>
        </div>
        <div class="left">&gt;</div><!--大于小于的符号-->
        <div class="right">&lt;</div>
        <div class="model">
            <div class="title">
                <h2>宋威龙</h2>
            </div>
            <div class="dots">
                <ul>
                    <li></li>
                    <li></li>
                    <li></li>
                </ul>
            </div>
        </div>
    </div>
</body>
</html>

CSS代码

.banner{
    width: 520px;
    height: 600px;
   
    margin: 1px auto;/*上下1em，左右auto*/
    overflow: hidden;/*溢出隐藏，让多张图叠在一起*/
    position: relative;
}

.banner .imgs{
    width: 1560px;
    height: 600px;
}
.banner .imgs img{
    width: 520px;
    height: 600px;

}
.banner .imgs a{
    float: left;
}
.banner .left,
.banner .right{
    position: absolute;
    left: 0;
    right: 0;
    height: 50px;
    width: 50px;
    color: #fff;
top: 0;
    bottom: 0;
    margin: auto   ;
    font-size: 3em;
    text-align: center;
    font-family:Arial ;
   line-height: 50px;
   border-radius: 50%; 
}
.banner .left:hover,
.banner .right:hover{
background: #fff;
color: red;

}
.banner .left{
    left: 450px;
 
}
.banner .right{
   right: 450px;
 
}
.banner .model{
    width: 100%;
    height:40px;
 background: rgba(0,0,0,.5);
    position: absolute;
    left: 0;
    bottom: 0;
    color: #fff;
   line-height: 40px;
   padding: 0 20px;/*内边距*/
   box-sizing: border-box;/*将内容设置为整个边框盒*/
}
.banner .model .title{
    float: left;
    font-weight: bold;
}
.banner .model .dots{
    float: right;
}
.banner .model .dots li{
    width: 10px;
    height: 8px;
    background: #ccc;
    display: inline-block;/*行块盒，可以适应行高，不会发生高度坍塌*/
    margin: 0 2px;/*行块盒之间上下为0，左右为1个字体大小*/
    border-radius: 50%;
    cursor: pointer;
}
.banner .model .dots li:hover{
    background: #369;
}

效果图

小贴士：通过设置边框四周的颜色可以实现生成一个三角形

div{

border: 100px solid ;

height: 0px;

width: 0px;

border-color: blue #fff #fff #fff;

}

四表单元素练习

HTML代码

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>重置页面</title>
    <link rel="stylesheet" href="css/reset.css">
    <link rel="stylesheet" href="css/reg.css">

</head>
<body>
    <div class="form">
        <h2>
            <span>注册</span>
        </h2>
        <div class="form-area">

        <div class="form-item">
            <input type="text" placeholder="账号">
        </div>
        <div class="form-item">
            <input type="password" placeholder="密码,(6-16字符组成,区分大小写)">
        </div>
        <div class="form-item">
            <div class="select clearfix">
                <div class="select-item">
                    <div class="title">
                        中国大陆
                    </div>
                   <ul>
                    <li class="selected">Lorem.</li>
                    <li>Ex!</li>
                    <li>Omnis!</li>
                    <li>Voluptatibus!</li>
                    <li>Eos.</li>
                    <li>Quos.</li>
                    <li>Illum.</li>
                    <li>Quisquam?</li>
                    <li>Odit?</li>
                    <li>Placeat!</li>
                    <li>Nemo!</li>
                    <li>Fugiat?</li>
                    <li>Culpa!</li>
                    <li>Quasi.</li>
                    <li>Reprehenderit?</li>
                    <li>Consectetur?</li>
                    <li>In.</li>
                    <li>Autem.</li>
                    <li>Vitae.</li>
                    <li>Ipsum.</li>
                    <li>Praesentium.</li>
                    <li>Fugit.</li>
                    <li>Pariatur.</li>
                    <li>Ut.</li>
                    <li>Sint.</li>
                    <li>Sit.</li>
                    <li>Perspiciatis?</li>
                    <li>Quod?</li>
                    <li>Sapiente.</li>
                    <li>Enim!</li>
                    <li>Corrupti!</li>
                    <li>Iste.</li>
                    <li>Minima.</li>
                    <li>Natus.</li>
                    <li>Eaque.</li>
                    <li>Excepturi.</li>
                    <li>Animi?</li>
                    <li>Sunt?</li>
                    <li>Nihil.</li>
                    <li>Odio?</li>
                    <li>Hic?</li>
                    <li>Iste.</li>
                    <li>Labore!</li>
                    <li>Eos.</li>
                    <li>Ducimus.</li>
                    <li>Nihil.</li>
                    <li>Facere.</li>
                    <li>Iure!</li>
                    <li>Neque!</li>
                    <li>Mollitia?</li>
                   </ul>
                </div>

                <div class="input">
                    <input type="text" placeholder="填写常用的手机号">
                </div>
            </div>
        </div>

        <div class="form-item">
            <input type="text">
            <button type="button">点击获取</button>
        </div>

        <div class="readme">
            <label >
                <input type="checkbox">
                <span>我已同意
                    <a href="">12345</a>和<a href="">678910</a>
                </span>
            </label>
        </div>

       <div class="form-item">
        <button>注册</button>
       </div>
       <div class="tip">
        <a href="">已有账号直接登录&gt;</a>
       </div>

    </div>
    </div>
</body>
</html>

CSS代码

.clearfix::after{
    content:"" ;
    display: block;
    clear: both;
}

.form{
    width: 980px;
    margin: 1em auto;
}

/*1. 所有表单框的样式*/
.form h2{
    text-align: center;
    font-size: 38px;
     border-bottom: 1px solid #ddd;
     height: 18px;
     margin-bottom: 30px;
}
.form h2 span{/*找到h2下的span元素给他设置一个白色背景把设置的下边框挡住*/
    background: #fff;
    padding: 0 20px;
}
.form-area{
    width: 423px;
    margin: 0 auto;
}

.form-area .form-item{
    margin: 50px 0;
}

/*统一的文本框样式*/

input[type="text"],input[type="password"]{
    border: 1px solid #dcdfe6;
    width: 100%;/*内容区的宽度，边框也有宽度，两者加在一起，会将宽度变大，所以用box-sizing: border-box;将边框宽度不算进内容里*/
    box-sizing: border-box;
    border-radius: 4px;
    height: 40px;
    text-indent: 1em;
    font-size: 14px;
    color: #606266;
}

input[type="text"]:hover,input[type="password"]:hover{
    border-color: #c0c4cc;/*鼠标点击时边框的颜色*/

}
input[type="text"]::placeholder,input[type="password"]::placeholder{
    color: #ccc;
   }

input[type="text"]:focus,input[type="password"]:focus{
    border-color: #00a1d6;
}

/*2.*/
.form-area .select .select-item,.form-area .select .input{
    float: left;
    height: 40px;
}
.form-area .select .select-item{
    width: 140px;
    border: 1px solid #dcdfe6;
    box-sizing: border-box;
    border-radius: 4px 0 0 4px;/*左上，右上，右下，左下依次设置圆角边框*/
/*   border-top-right-radius:0 ;*/
    border-right: none;
    position: relative;
}
.form-area .select .select-item ul{
    /*最大高度256像素*/
    max-height: 256px;
    background: #fff;/*设置背景颜色来遮挡溢出的部分*/
    color: #606266;
    position: absolute;
  z-index: 1;/*  相对于图层往上一层，遮挡溢出的部分*/
    left: 0;/*设置边框*/
    top: 50px;
    width: 100%;
    box-sizing: border-box;
    border: 1px solid #dcdfe6;
    border-radius: 4px 0 0 4px;
    padding: 10px 0;
    overflow-y:auto ;/*方向上溢出的话，产生滚动条*/
  display: none ;  /*隐藏内容*/

}
.form-area .select .select-item ul li{
    height: 34px;
    padding: 0 20px;
    cursor: pointer;
}
.form-area .select .select-item ul li.selected{
    color: #00a1d6;
    font-weight: bold;
}
.form-area .select .select-item ul li:hover{
    background: #f5f7fa;
}

.form-area .select .input{
    width: 283px;
}
.form-area .select .select-item .title{
    height: 40px;
    line-height: 40px;
    padding: 0 20px;
    color:#909399 ;
    cursor: pointer;
}
.form-area .select .input input{
    border-radius:0 4px 4px 0 ;
}

效果图

好啦！这周的分享就到这里啦！大家记得练习哦！我们下周同一时间同一地点不见不散！！！