本文根据 Devhints / Sass 翻译。代码示例及版本范围沿用原文。原文标注更新日期:2020-07-03。
基础
简介
这是关于……的快速参考 Sass 样式表.
- Sass 文档 (sass-lang.com)
变量
$red: #833;
body {
color: $red;
}
嵌套 (Nesting)
.markdown-body {
a {
color: blue;
&:hover {
color: red;
}
}
}
针对属性
text: {
align: center; // like text-align: center
transform: uppercase; // like text-transform: uppercase
}
注释
/* Block comments */
// Line comments
混合 (Mixins)
@mixin heading-font {
font-family: sans-serif;
font-weight: bold;
}
h1 {
@include heading-font;
}
带参数
@mixin font-size($n) {
font-size: $n * 1.2em;
}
body {
@include font-size(2);
}
带默认值
@mixin pad($n: 10px) {
padding: $n;
}
body {
@include pad(15px);
}
带默认变量
// Set a default value
$default-padding: 10px;
@mixin pad($n: $default-padding) {
padding: $n;
}
body {
@include pad(15px);
}
扩展
.button {
···
}
.push-button {
@extend .button;
}
组合
@import './other_sass_file';
@use './other_sass_file';
该 @import 不建议使用此规则,因为它最终会被 从语言中移除.
相反,我们应该使用 @use 规则.
该 .scss 或 .sass 扩展名是可选的。
颜色函数
rgba
rgb(100, 120, 140)
rgba(100, 120, 140, .5)
rgba($color, .5)
混合
mix($a, $b, 10%) // 10% a, 90% b
修改 HSLA
darken($color, 5%)
lighten($color, 5%)
saturate($color, 5%)
desaturate($color, 5%)
grayscale($color)
adjust-hue($color, 15deg)
complement($color) // like adjust-hue(_, 180deg)
invert($color)
fade-in($color, .5) // aka opacify()
fade-out($color, .5) // aka transparentize() - halves the opacity
rgba($color, .5) // sets alpha to .5
获取单个数值
HSLA
hue($color) // → 0deg..360deg
saturation($color) // → 0%..100%
lightness($color) // → 0%..100%
alpha($color) // → 0..1 (aka opacity())
RGB
red($color) // → 0..255
green($color)
blue($color)
调整
// Changes by fixed amounts
adjust-color($color, $blue: 5)
adjust-color($color, $lightness: -30%) // like darken(_, 30%)
adjust-color($color, $alpha: -0.4) // like fade-out(_, .4)
adjust-color($color, $hue: 30deg) // like adjust-hue(_, 15deg)
// Changes via percentage
scale-color($color, $lightness: 50%)
// Changes one property completely
change-color($color, $hue: 180deg)
change-color($color, $blue: 250)
支持: $red $green $blue $hue $saturation $lightness $alpha
其他函数
字符串
unquote('hello')
quote(hello)
to-upper-case(hello)
to-lower-case(hello)
str-length(hello world)
str-slice(hello, 2, 5) // "ello" - it's 1-based, not 0-based
str-insert("abcd", "X", 1) // "Xabcd"
单位
unit(3em) // 'em'
unitless(100px) // false
数字
floor(3.5)
ceil(3.5)
round(3.5)
abs(3.5)
min(1, 2, 3)
max(1, 2, 3)
percentage(.5) // 50%
random(3) // 0..3
杂项
variable-exists(red) // checks for $red
mixin-exists(red-text) // checks for @mixin red-text
function-exists(redify)
global-variable-exists(red)
selector-append('.menu', 'li', 'a') // .menu li a
selector-nest('.menu', '&:hover li') // .menu:hover li
selector-extend(...)
selector-parse(...)
selector-replace(...)
selector-unify(...)
特性检测
功能检查
feature-exists(global-variable-shadowing)
特性
- 全局变量遮蔽 (global-variable-shadowing)
- 扩展选择器伪类 (extend-selector-pseudoclass)
- Level 3 单位 (units-level-3)
- @error 指令
循环
For 循环
@for $i from 1 through 4 {
.item-#{$i} { left: 20px * $i; }
}
Each 循环(简单)
$menu-items: home about services contact;
@each $item in $menu-items {
.photo-#{$item} {
background: url('images/#{$item}.jpg');
}
}
Each 循环(嵌套)
$backgrounds: (home, 'home.jpg'), (about, 'about.jpg');
@each $id, $image in $backgrounds {
.photo-#{$id} {
background: url($image);
}
}
While 循环
$i: 6;
@while $i > 0 {
.item-#{$i} { width: 2em * $i; }
$i: $i - 2;
}
其他功能
条件判断
@if $position == 'left' {
position: absolute;
left: 0;
}
@else if $position == 'right' {
position: absolute;
right: 0;
}
@else {
position: static;
}
插值
.#{$klass} { ... } // Class
call($function-name) // Functions
@media #{$tablet}
font: #{$size}/#{$line-height}
url("#{$background}.jpg")
列表 (Lists)
$list: (a b c);
nth($list, 1) // starts with 1
length($list)
@each $item in $list { ... }
映射 (Maps)
$map: (key1: value1, key2: value2, key3: value3);
map-get($map, key1)