css3基礎-選擇器+邊框與圓角+背景與漸變

Css3選擇器相關： section > div直接子元素選擇器 div + article相鄰兄弟選擇器（在元素之後出現） div ~ article通用兄弟選擇器（在元素之後出現）屬性選擇器： a[href] { text-decoration: none; } a[href="#"] { c ...

Css3選擇器相關：

section > div直接子元素選擇器

div + article相鄰兄弟選擇器（在元素之後出現）

div ~ article通用兄弟選擇器（在元素之後出現）

屬性選擇器：

a[href] {
    text-decoration: none;
}
a[href="#"] {
    color: #f00;
}
/*包含two且屬性值用空格分隔：*/
a[class~="two"] {
    color: #ff0;
}
/*屬性的第一個值以#開頭：*/
a[href^="#"] {
    color: #0f0;
}
/*以#結尾：*/
a[href$="#"] {
    color: #00f;
}
/*包含#：*/
a[href*="#"] {
    color: #0ff;
}
/*第一個屬性值以#-開頭：*/
a[href|="#"] {
    color: #f0f;
}

UI元素偽類：

Input:disabled

Input:enabled

Input:checked

div:first-child匹配屬於其父元素的第1個子元素且是div，計數時不分類型，顯示時分類型

div:last-child匹配屬於其父元素的最後1個子元素且是div，計數時不分類型，顯示時分類型div:nth-child(2) 匹配屬於其父元素的第n個子元素且是div，計數時不分類型，顯示時分類型div:nth-lat-child(2) 匹配屬於其父元素的第n個子元素且是div，計數時不分類型，顯示時分類型

n匹配下標，從0開始計算：

li:nth-child(2n) 雙數

li:nth-child(2n+1) 單數

li:nth-child(n+4)

li:nth-child(odd) 奇數，下標從1開始計算

li:nth-child(even) 偶數，下標從1開始計算

li:nth-last-child(3) 倒數第3個

article:only-child 屬於父元素的唯一元素，且是article(沒有任何其他子元素)

div:nth-of-type(2) 匹配屬於其父元素的第2個子元素且是div，計數時分類型

div:nth-last-of-type(2)

div:first-of-type div:last-of-type

article:only-of-type 屬於父元素的唯一article元素（可以有其他類型的子元素）

div:empty 沒有子元素的div元素（包括文本也沒有）

a:not(:last-of-type) 不是最後一個a子元素

id選擇器權重大於屬性選擇器

.red > [class=”red”]

Css偽元素：

div::selection 文本被選中後的樣式

::-moz-selection 火狐

Css3邊框與圓角：

四個值按照順時針方向來

Border-radius相容性寫法：

-webkit-border-radius: 50%;
       -moz-border-radius: 50%;
        -ms-border-radius: 50%;
         -o-border-radius: 50%;
            border-radius: 50%;

box-shadow水平偏移垂直偏移模糊擴展顏色內部

box-shadow: 50px 30px 0px 0px yellow inset;

border-image-repeat:stretch（拉伸）/repeat（重覆）/round（鋪滿）/initial/inherit

border-image-source: url("border.jpg");
    border-image-slice: 50%;/*圖像邊界向內偏移*/
    border-image-width: 50%;/*圖像邊界的寬度*/
    border-image-outset: 2; /*在邊框外部繪製*/
    border-image-repeat: repeat;

css3背景與漸變：

背景繪製區域（顯示範圍）

background-clip: border-box;
background-clip: padding-box;
background-clip: content-box;

背景圖像定位（起始位置，原點位置，與偏移搭配使用）

background-origin: border-box;
background-origin: padding-box;
background-origin: content-box;
background-position:10px 10px; /*與偏移搭配使用*/

background-size只寫一個值，第二個預設是auto，根據比例等比縮放

background-size: contain; /*等比縮放到某一邊達到容器邊緣*/
background-size: cover;/*等比縮放填滿容器*/
background-size: 800px 500px;
background-size: 800px;
background-size: 50% 50%;
background-size: 50%;
background-size: 100% 100%;
background-size: 100%;

background-image多重背景，前面的會覆蓋後面的

background-image: url('bg2.png'), url('bg1.jpg');

demo：

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>background-image</title>
    <style type="text/css">
        div{
            width:300px;
            height:300px;
            background:url(1.jpg) no-repeat center top,
            url(2.jpg) no-repeat center 100px,
            url(3.jpg) no-repeat center 200px;
            margin:0 auto;
        }
    </style>
</head>
<body>
    <div></div>
</body>
</html>

預設從上到下漸變：

div {
    width: 800px; height: 500px;
    background: -webkit-linear-gradient(red, blue);
    background:    -moz-linear-gradient(red, blue);
    background:      -o-linear-gradient(red, blue);
    background:         linear-gradient(red, blue);
}

從左到右漸變

div {
    width: 800px; height: 500px;
    background: -webkit-linear-gradient(left, red , blue);
    background:    -moz-linear-gradient(right, red, blue);
    background:      -o-linear-gradient(right, red, blue);
    background:         linear-gradient(to right, red , blue);
}

左上角開始的對角線漸變

div {
    width: 800px; height: 500px;
    background: -webkit-linear-gradient(       left top, red, yellow, blue);
    background:    -moz-linear-gradient(   right bottom, red, yellow, blue);
    background:      -o-linear-gradient(   right bottom, red, yellow, blue);
    background:         linear-gradient(to right bottom, red, yellow, blue);
}

角度控制方向

角度漸變是水平線和漸變線之間的角度，0deg是從下到上，90度是從左到右

div {
    width: 800px; height: 500px;
    background: -webkit-linear-gradient(135deg, red, yellow, blue);
    background:    -moz-linear-gradient(135deg, red, yellow, blue);
    background:      -o-linear-gradient(135deg, red, yellow, blue);
    background:         linear-gradient(135deg, red, yellow, blue);
}

漸變具體位置控制

div {
    width: 800px; height: 500px;
    background: -webkit-linear-gradient(90deg, red 10%, orange 15%, yellow 20%, green 50%, blue 70%, indigo 80%, violet 100%);
    background:    -moz-linear-gradient(90deg, red 10%, orange 15%, yellow 20%, green 50%, blue 70%, indigo 80%, violet 100%);
    background:      -o-linear-gradient(90deg, red 10%, orange 15%, yellow 20%, green 50%, blue 70%, indigo 80%, violet 100%);
    background:         linear-gradient(90deg, red 10%, orange 15%, yellow 20%, green 50%, blue 70%, indigo 80%, violet 100%);
}

透明色漸變

div {
    width: 800px; height: 500px;
    background: -webkit-linear-gradient(90deg, rgba(255, 0, 0, 0), rgba(255, 0, 0, 1));
    background:    -moz-linear-gradient(90deg, rgba(255, 0, 0, 0), rgba(255, 0, 0, 1));
    background:      -o-linear-gradient(90deg, rgba(255, 0, 0, 0), rgba(255, 0, 0, 1));
    background:         linear-gradient(90deg, rgba(255, 0, 0, 0), rgba(255, 0, 0, 1));
}

重覆漸變

div {
    width: 800px; height: 500px;
    background: -webkit-repeating-linear-gradient(90deg, red 0%, blue 10%, red 20%);
    background:    -moz-repeating-linear-gradient(90deg, red 0%, blue 10%, red 20%);
    background:      -o-repeating-linear-gradient(90deg, red 0%, blue 10%, red 20%);
    background:         repeating-linear-gradient(90deg, red 0%, blue 10%, red 20%);
}

徑向漸變，從內到外

div {
    width: 800px; height: 500px;
    background: -webkit-radial-gradient(red, blue);
    background:    -moz-radial-gradient(red, blue);
    background:      -o-radial-gradient(red, blue);
    background:         radial-gradient(red, blue);
}

圓形漸變

div {
    width: 800px; height: 500px;
    background: -webkit-radial-gradient(circle, red, blue);
    background:    -moz-radial-gradient(circle, red, blue);
    background:      -o-radial-gradient(circle, red, blue);
    background:         radial-gradient(circle, red, blue);
}

橢圓形漸變

div {
    width: 800px; height: 500px;
    background: -webkit-radial-gradient(ellipse, red, blue);
    background:    -moz-radial-gradient(ellipse, red, blue);
    background:      -o-radial-gradient(ellipse, red, blue);
    background:         radial-gradient(ellipse, red, blue);
}

漸變從圓心到最近邊

div.closest-side {
    width: 300px; height: 200px; margin: 50px;
    background: -webkit-radial-gradient(30% 70%, circle closest-side, red, blue);
    background:    -moz-radial-gradient(30% 70%, circle closest-side, red, blue);
    background:      -o-radial-gradient(30% 70%, circle closest-side, red, blue);
    background:         radial-gradient(30% 70%, circle closest-side, red, blue);
}

漸變從圓心到最遠邊

div.farthest-side {
    width: 300px; height: 200px; margin: 50px;
    background: -webkit-radial-gradient(30% 70%, farthest-side, red, blue);
    background:    -moz-radial-gradient(30% 70%, farthest-side, red, blue);
    background:      -o-radial-gradient(30% 70%, farthest-side, red, blue);
    background:         radial-gradient(30% 70%, farthest-side, red, blue);
}

漸變從圓心到最近角

div.closest-corner {
    width: 300px; height: 200px; margin: 50px;
    background: -webkit-radial-gradient(30% 70%, closest-corner, red, blue);
    background:    -moz-radial-gradient(30% 70%, closest-corner, red, blue);
    background:      -o-radial-gradient(30% 70%, closest-corner, red, blue);
    background:         radial-gradient(30% 70%, closest-corner, red, blue);
}

漸變從圓心到最遠角

div.farthest-corner {
    width: 300px; height: 200px; margin: 50px;
    background: -webkit-radial-gradient(30% 70%, farthest-corner, red, blue);
    background:    -moz-radial-gradient(30% 70%, farthest-corner, red, blue);
    background:      -o-radial-gradient(30% 70%, farthest-corner, red, blue);
    background:         radial-gradient(30% 70%, farthest-corner, red, blue);
}

IE漸變從上到下

div {
    width: 800px;
    height: 500px;
    filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#ff0000', endColorstr='#0000ff',GradientType=0 );
}

IE漸變從左到右

div {
    width: 800px;
    height: 500px;
    filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#ff0000', endColorstr='#0000ff',GradientType=1 );
}

Demo：

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>線性漸變 - 特殊案例</title>
<style type="text/css">
div {
    width: 800px; height: 500px; background: #abcdef; background-size: 50px 50px;
    background-image:
        -webkit-gradient(linear, 0 0, 100% 100%, color-stop(.25, #555), color-stop(.25, transparent), to(transparent)),
        -webkit-gradient(linear, 0 100%, 100% 0, color-stop(.25, #555), color-stop(.25, transparent), to(transparent)),
        -webkit-gradient(linear, 0 0, 100% 100%, color-stop(.75, transparent), color-stop(.75, #555)),
        -webkit-gradient(linear, 0 100%, 100% 0, color-stop(.75, transparent), color-stop(.75, #555));
    background-image:
        -moz-linear-gradient(45deg, #555 25%, transparent 25%, transparent),
        -moz-linear-gradient(-45deg, #555 25%, transparent 25%, transparent),
        -moz-linear-gradient(45deg, transparent 75%, #555 75%),
        -moz-linear-gradient(-45deg, transparent 75%, #555 75%);
    background-image:
        -o-linear-gradient(45deg, #555 25%, transparent 25%, transparent),
        -o-linear-gradient(-45deg, #555 25%, transparent 25%, transparent),
        -o-linear-gradient(45deg, transparent 75%, #555 75%),
        -o-linear-gradient(-45deg, transparent 75%, #555 75%);
    background-image:
        linear-gradient(45deg, #555 25%, transparent 25%, transparent),
        linear-gradient(-45deg, #555 25%, transparent 25%, transparent),
        linear-gradient(45deg, transparent 75%, #555 75%),
        linear-gradient(-45deg, transparent 75%, #555 75%);
}
</style>
</head>
<body>
<div></div>
</body>
</html>