CSS学习总结1：CSS样式

1、CSS背景

属性

background-color：为元素设置背景色，值可以是任何合法的颜色值。实例：p {background-color: gray;}

background-image：为元素设置背景图片，其值必须通过URL值来设置。实例：body {background-image: url(/i/eg_bg_04.gif);}

background-repeat：背景重复，其值有：repeat(水平竖直方向均平铺)、no-repeat(不平铺)、repeat-x(水平方向平铺)、repeat-y(竖直方向平铺)。

background-position：背景定位，其值可以是关键字(center、top、bottom、right、left)、百分数值(background-position:66% 33%;)、长度值(background-position:50px 100px;)

background-attachment：背景关联，其值有：fixed(声明图像相对于可视区是固定的)、scroll(默认，背景会随文档滚动)。

2、CSS文本

属性

text-indent：缩进文本，其值为：text-indent可以使用所有长度单位，包括百分比，值可正可负。(百分数要相对于缩进元素父元素的宽度。)

text-align：对齐，其值为：left(左齐右锯齿)、right(右齐左锯齿)、center(仅居中文本，不影响元素)、<CENTER>(不仅影响文本，还把整个元素居中)、justufy(两端对齐)。

word-spacing：字间隔，该属性可以改变字(单词)之间的标准间隔，其值可正可负，默认值：normal(相当于设置值为0)。

letter-spacing：字母间隔，与word-spacing区别在于，letter-spacing修改的是字符或字母之间的间隔，而非单词。其值可正可负，单位是所有长度。实例：h1 {letter-spacing: -0.5em}。

text-transform：处理文本大小写，其值为：none(不做任何改动)、uppercase(全大写)、lowercase(全小写)、capitalize(首字母大写)

text-decoration：文本装饰，其值为：none、underline(增加下划线)、overline(增加上划线)、line-through(文本贯穿线)、blink(主流浏览器均不支持)

white-space：处理空白符，其值为：normal、pre、nowrap、pre-wrap、pre-line；aaarticlea/jpeg;base64,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" alt="" />

3、CSS字体

属性

font-family：定义文本的字体系列。

font-style：设置字体风格，其值为：normal(文本正常显示)、italic(文本斜体显示)、oblique(文本倾斜显示)；说明：italic是一种简单的字体风格，oblique则是正常竖直文本的一个倾斜版本。

font-variant：设置小型大写字母。小型大写字母不是一般的大写字母，也不是小写字母，这种字母采用不同大小的大写字母。

font-weight：设置文本粗细，其值为：bold(粗体，数值约为700)、normal(数值约为400)、值(关键字100~900为字体指定了9级加粗度)。

font-size：字体大小，其值为：px(不推荐)、em(推荐使用，16px=1em)、结合使用百分比和EM。1em的默认尺寸是16px。转换公式：pixels/16=em (注：16 等于父元素的默认字体大小，假设　　　　　父元素的 font-size 为 20px，那么公式需改为：pixels/20=em)。在所有浏览器中均有效的方案是为 body 元素（父元素）以百分比设置默认的 font-size 值：

body {font-size:100%;}

h1 {font-size:3.75em;}

h2 {font-size:2.5em;}

p {font-size:0.875em;}

4、CSS链接

属性

链接的四种状态：

a：link—普通的、未被访问的链接；

a：visited—用户已访问的链接；

a：hover—鼠标指针位于链接的上方；

a：active—链接被点击的时刻。

当为链接的不同状态设置样式时，请按照一下次序规则：

1、a：hover必须位于a：link和a：visited之后；

2、a：active必须位于a：hover之后

实例：

a:link {text-decoration:none;} /* 未被访问的链接 */
a:visited {text-decoration:none;} /* 已被访问的链接 */
a:hover {text-decoration:underline;} /* 鼠标指针移动到链接上 */
a:active {text-decoration:underline;} /* 正在被点击的链接 */

background-color：背景色，规定链接的背景色。实例：a:link {background-color:#B2FF99;}

5、CSS表格

属性

表格边框：CSS 中设置表格边框，请使用 border 属性。实例：

table, th, td

  {

  border: 1px solid blue;

  }

注意：上例中的表格具有双线条边框。这是由于 table、th 以及 td 元素都有独立的边框。如果需要把表格显示为单线条边框，请使用 border-collapse 属性。

折叠边框：border-collapse 属性设置是否将表格边框折叠为单一边框。实例：

table

  {

  border-collapse:collapse;

  }

table,th, td

  {

  border: 1px solid black;

  }

表格高度和宽度：通过 width 和 height 属性定义表格的宽度和高度。实例：

table

  {

  width:100%;

  }

th

  {

  height:50px;

  }

表格文本对齐：text-align 和 vertical-align 属性设置表格中文本的对齐方式。text-align设置水平对齐方式(左对齐、右对齐、居中)，vertical-align设置竖直对齐方式(顶部对齐、底部对齐、居中对齐)。实例：

td

  {

  text-align:right;

  }
td

  {

  height:50px;

  vertical-align:bottom;

  }

表格内边距：如需控制表格中内容与边框的距离，请为 td 和 th 元素设置 padding 属性：

td

  {

  padding:15px;

  }

表格颜色：面的例子设置边框的颜色，以及 th 元素的文本和背景颜色：

table, td, th

  {

  border:1px solid green;

  }

th

  {

  background-color:green;

  color:white;

  }