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halo`s Docs

Sass

Sass Basics

Introduction

Variables

$defaultLinkColor: #46eac2;


a {
  color: $defaultLinkColor;
}

String interpolation

$wk: -webkit-;


.rounded-box {
  #{$wk}border-radius: 4px;
}

Comments

/*
 Block comments
 Block comments
 Block comments
*/


// Line comments

Mixins

@mixin heading-font {
  font-family: sans-serif;
  font-weight: bold;
}
h1 {
  @include heading-font;
}

See: Mixins

Nesting {.row-span-2}

.markdown-body {
  a {
    color: blue;
    &:hover {
      color: red;
    }
  }
}

to properties

text: {
  // like text-align: center
  align: center;
  // like text-transform: uppercase
  transform: uppercase;
}

Extend

.button {
    ···
}
.push-button {
  @extend .button;
}

@import

@import "./other_sass_file";
@import "/code", "lists";


// Plain CSS @imports
@import "theme.css";
@import url(theme);

The .sass or .sass extension is optional.

Sass Mixins

Parameters

@mixin font-size($n) {
  font-size: $n * 1.2em;
}
body {
  @include font-size(2);
}

Default values

@mixin pad($n: 10px) {
  padding: $n;
}
body {
  @include pad(15px);
}

Default variable

$default-padding: 10px;


@mixin pad($n: $default-padding) {
  padding: $n;
}


body {
  @include pad(15px);
}

Sass Color functions {.cols-2}

rgba

rgb(100, 120, 140)
rgba(100, 120, 140, .5)
rgba($color, .5)

Mixing

mix($a, $b, 10%)   // 10% a, 90% b

Modifying 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()
rgba($color, .5)      // sets alpha to .5

Getting individual values

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)

See: hue(), red()

Adjustments

// Changes by fixed amounts
adjust-color($color, $blue: 5)
adjust-color($color, $lightness: -30%) // darken(_, 30%)
adjust-color($color, $alpha: -0.4)     // fade-out(_, .4)
adjust-color($color, $hue: 30deg)      // adjust-hue(_, 15deg)
// Changes via percentage
scale-color($color, $lightness: 50%)
// Changes one property completely
change-color($color, $hue: 180deg)
change-color($color, $blue: 250)

Supported: $red, $green, $blue, $hue, $saturation, $lightness, $alpha

Sass Other functions {.cols-2}

Strings

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"

Units

unit(3em)        // 'em'
unitless(100px)  // false

Numbers

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

Misc

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(...)

Sass Feature checks {.cols-2}

Feature check

feature-exists(global-variable-shadowing)

Features

  • global-variable-shadowing
  • extend-selector-pseudoclass
  • units-level-3
  • at-error

Sass Loops

For loops

@for $i from 1 through 4 {
  .item-#{$i} {
    left: 20px * $i;
  }
}

Each loops (simple)

$menu-items: home about contact;


@each $item in $menu-items {
  .photo-#{$item} {
    background: url("#{$item}.jpg");
  }
}

Each loops (nested)

$backgrounds: (home, "home.jpg"), (about, "about.jpg");


@each $id, $image in $backgrounds {
  .photo-#{$id} {
    background: url($image);
  }
}

While loops

$i: 6;
@while $i > 0 {
  .item-#{$i} {
    width: 2em * $i;
  }
  $i: $i - 2;
}

Sass Other features

Conditionals {.row-span-2}

@if $position == "left" {
  position: absolute;
  left: 0;
} @else if $position == "right" {
  position: absolute;
  right: 0;
} @else {
  position: static;
}

Interpolation

.#{$klass} { ... }      // Class
call($function-name)    // Functions


@media #{$tablet}
font: #{$size}/#{$line-height}
url("#{$background}.jpg")

Lists

$list: (a b c);


nth($list, 1)  // starts with 1
length($list)


@each $item in $list { ... }

Maps {.col-span-2}

$map: (key1: value1, key2: value2, key3: value3);


map-get($map, key1)