縮進

使用soft tab（4個空格）。

.element {
    position: absolute;
    top: 10px;
    left: 10px;

    border-radius: 10px;
    width: 50px;
    height: 50px;
}

分號

每個屬性聲明末尾都要加分號。

.element {
    width: 20px;
    height: 20px;

    background-color: red;
}

空格

以下幾種情況不需要空格：

• 屬性名后
• 多個規(guī)則的分隔符','前
• !important?'!'后
• 屬性值中'('后和')'前
• 行末不要有多余的空格

以下幾種情況需要空格：

• 屬性值前
• 選擇器'>', '+', '~'前后
• '{'前
• !important?'!'前
• @else?前后
• 屬性值中的','后
• 注釋'/'后和'/'前

/* not good */
.element {
    color :red! important;
    background-color: rgba(0,0,0,.5);
}

/* good */
.element {
    color: red !important;
    background-color: rgba(0, 0, 0, .5);
}

/* not good */
.element ,
.dialog{
    ...
}

/* good */
.element,
.dialog {

}

/* not good */
.element>.dialog{
    ...
}

/* good */
.element > .dialog{
    ...
}

/* not good */
.element{
    ...
}

/* good */
.element {
    ...
}

/* not good */
@if{
    ...
}@else{
    ...
}

/* good */
@if {
    ...
} @else {
    ...
}

空行

以下幾種情況需要空行：

• 文件最后保留一個空行
• '}'后最好跟一個空行，包括scss中嵌套的規(guī)則
• 屬性之間需要適當?shù)目招?，具體見屬性聲明順序

/* not good */
.element {
    ...
}
.dialog {
    color: red;
    &:after {
        ...
    }
}

/* good */
.element {
    ...
}

.dialog {
    color: red;

    &:after {
        ...
    }
}

換行

以下幾種情況不需要換行：

• '{'前

以下幾種情況需要換行：

• '{'后和'}'前
• 每個屬性獨占一行
• 多個規(guī)則的分隔符','后

/* not good */
.element
{color: red; background-color: black;}

/* good */
.element {
    color: red;
    background-color: black;
}

/* not good */
.element, .dialog {
    ...
}

/* good */
.element,
.dialog {
    ...
}

注釋

注釋統(tǒng)一用'/ /'（scss中也不要用'//'），具體參照右邊的寫法；

縮進與下一行代碼保持一致；

可位于一個代碼行的末尾，與代碼間隔一個空格。

/* Modal header */
.modal-header {
    ...
}

/*
 * Modal header
 */
.modal-header {
    ...
}

.modal-header {
    /* 50px */
    width: 50px;

    color: red; /* color red */
}

引號

最外層統(tǒng)一使用雙引號；

url的內(nèi)容要用引號；

屬性選擇器中的屬性值需要引號。

.element:after {
    content: "";
    background-image: url("logo.png");
}

li[data-type="single"] {
    ...
}

命名

• 類名使用小寫字母，以中劃線分隔
• id采用駝峰式命名
• scss中的變量、函數(shù)、混合、placeholder采用駝峰式命名

/* class */
.element-content {
    ...
}

/* id */
#myDialog {
    ...
}

/* 變量 */
$colorBlack: #000;

/* 函數(shù) */
@function pxToRem($px) {
    ...
}

/* 混合 */
@mixin centerBlock {
    ...
}

/* placeholder */
%myDialog {
    ...
}

屬性聲明順序

相關(guān)的屬性聲明按右邊的順序做分組處理，組之間需要有一個空行。

.declaration-order {
    display: block;
    float: right;

    position: absolute;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    z-index: 100;

    border: 1px solid #e5e5e5;
    border-radius: 3px;
    width: 100px;
    height: 100px;

    font: normal 13px "Helvetica Neue", sans-serif;
    line-height: 1.5;
    text-align: center;

    color: #333;
    background-color: #f5f5f5;

    opacity: 1;
}

// 下面是推薦的屬性的順序
[
    [
        "display",
        "visibility",
        "float",
        "clear",
        "overflow",
        "overflow-x",
        "overflow-y",
        "clip",
        "zoom"
    ],
    [
        "table-layout",
        "empty-cells",
        "caption-side",
        "border-spacing",
        "border-collapse",
        "list-style",
        "list-style-position",
        "list-style-type",
        "list-style-image"
    ],
    [
        "-webkit-box-orient",
        "-webkit-box-direction",
        "-webkit-box-decoration-break",
        "-webkit-box-pack",
        "-webkit-box-align",
        "-webkit-box-flex"
    ],
    [
        "position",
        "top",
        "right",
        "bottom",
        "left",
        "z-index"
    ],
    [
        "margin",
        "margin-top",
        "margin-right",
        "margin-bottom",
        "margin-left",
        "-webkit-box-sizing",
        "-moz-box-sizing",
        "box-sizing",
        "border",
        "border-width",
        "border-style",
        "border-color",
        "border-top",
        "border-top-width",
        "border-top-style",
        "border-top-color",
        "border-right",
        "border-right-width",
        "border-right-style",
        "border-right-color",
        "border-bottom",
        "border-bottom-width",
        "border-bottom-style",
        "border-bottom-color",
        "border-left",
        "border-left-width",
        "border-left-style",
        "border-left-color",
        "-webkit-border-radius",
        "-moz-border-radius",
        "border-radius",
        "-webkit-border-top-left-radius",
        "-moz-border-radius-topleft",
        "border-top-left-radius",
        "-webkit-border-top-right-radius",
        "-moz-border-radius-topright",
        "border-top-right-radius",
        "-webkit-border-bottom-right-radius",
        "-moz-border-radius-bottomright",
        "border-bottom-right-radius",
        "-webkit-border-bottom-left-radius",
        "-moz-border-radius-bottomleft",
        "border-bottom-left-radius",
        "-webkit-border-image",
        "-moz-border-image",
        "-o-border-image",
        "border-image",
        "-webkit-border-image-source",
        "-moz-border-image-source",
        "-o-border-image-source",
        "border-image-source",
        "-webkit-border-image-slice",
        "-moz-border-image-slice",
        "-o-border-image-slice",
        "border-image-slice",
        "-webkit-border-image-width",
        "-moz-border-image-width",
        "-o-border-image-width",
        "border-image-width",
        "-webkit-border-image-outset",
        "-moz-border-image-outset",
        "-o-border-image-outset",
        "border-image-outset",
        "-webkit-border-image-repeat",
        "-moz-border-image-repeat",
        "-o-border-image-repeat",
        "border-image-repeat",
        "padding",
        "padding-top",
        "padding-right",
        "padding-bottom",
        "padding-left",
        "width",
        "min-width",
        "max-width",
        "height",
        "min-height",
        "max-height"
    ],
    [
        "font",
        "font-family",
        "font-size",
        "font-weight",
        "font-style",
        "font-variant",
        "font-size-adjust",
        "font-stretch",
        "font-effect",
        "font-emphasize",
        "font-emphasize-position",
        "font-emphasize-style",
        "font-smooth",
        "line-height",
        "text-align",
        "-webkit-text-align-last",
        "-moz-text-align-last",
        "-ms-text-align-last",
        "text-align-last",
        "vertical-align",
        "white-space",
        "text-decoration",
        "text-emphasis",
        "text-emphasis-color",
        "text-emphasis-style",
        "text-emphasis-position",
        "text-indent",
        "-ms-text-justify",
        "text-justify",
        "letter-spacing",
        "word-spacing",
        "-ms-writing-mode",
        "text-outline",
        "text-transform",
        "text-wrap",
        "-ms-text-overflow",
        "text-overflow",
        "text-overflow-ellipsis",
        "text-overflow-mode",
        "-ms-word-wrap",
        "word-wrap",
        "-ms-word-break",
        "word-break"
    ],
    [
        "color",
        "background",
        "filter:progid:DXImageTransform.Microsoft.AlphaImageLoader",
        "background-color",
        "background-image",
        "background-repeat",
        "background-attachment",
        "background-position",
        "-ms-background-position-x",
        "background-position-x",
        "-ms-background-position-y",
        "background-position-y",
        "-webkit-background-clip",
        "-moz-background-clip",
        "background-clip",
        "background-origin",
        "-webkit-background-size",
        "-moz-background-size",
        "-o-background-size",
        "background-size"
    ],
    [
        "outline",
        "outline-width",
        "outline-style",
        "outline-color",
        "outline-offset",
        "opacity",
        "filter:progid:DXImageTransform.Microsoft.Alpha(Opacity",
        "-ms-filter:\\'progid:DXImageTransform.Microsoft.Alpha",
        "-ms-interpolation-mode",
        "-webkit-box-shadow",
        "-moz-box-shadow",
        "box-shadow",
        "filter:progid:DXImageTransform.Microsoft.gradient",
        "-ms-filter:\\'progid:DXImageTransform.Microsoft.gradient",
        "text-shadow"
    ],
    [
        "-webkit-transition",
        "-moz-transition",
        "-ms-transition",
        "-o-transition",
        "transition",
        "-webkit-transition-delay",
        "-moz-transition-delay",
        "-ms-transition-delay",
        "-o-transition-delay",
        "transition-delay",
        "-webkit-transition-timing-function",
        "-moz-transition-timing-function",
        "-ms-transition-timing-function",
        "-o-transition-timing-function",
        "transition-timing-function",
        "-webkit-transition-duration",
        "-moz-transition-duration",
        "-ms-transition-duration",
        "-o-transition-duration",
        "transition-duration",
        "-webkit-transition-property",
        "-moz-transition-property",
        "-ms-transition-property",
        "-o-transition-property",
        "transition-property",
        "-webkit-transform",
        "-moz-transform",
        "-ms-transform",
        "-o-transform",
        "transform",
        "-webkit-transform-origin",
        "-moz-transform-origin",
        "-ms-transform-origin",
        "-o-transform-origin",
        "transform-origin",
        "-webkit-animation",
        "-moz-animation",
        "-ms-animation",
        "-o-animation",
        "animation",
        "-webkit-animation-name",
        "-moz-animation-name",
        "-ms-animation-name",
        "-o-animation-name",
        "animation-name",
        "-webkit-animation-duration",
        "-moz-animation-duration",
        "-ms-animation-duration",
        "-o-animation-duration",
        "animation-duration",
        "-webkit-animation-play-state",
        "-moz-animation-play-state",
        "-ms-animation-play-state",
        "-o-animation-play-state",
        "animation-play-state",
        "-webkit-animation-timing-function",
        "-moz-animation-timing-function",
        "-ms-animation-timing-function",
        "-o-animation-timing-function",
        "animation-timing-function",
        "-webkit-animation-delay",
        "-moz-animation-delay",
        "-ms-animation-delay",
        "-o-animation-delay",
        "animation-delay",
        "-webkit-animation-iteration-count",
        "-moz-animation-iteration-count",
        "-ms-animation-iteration-count",
        "-o-animation-iteration-count",
        "animation-iteration-count",
        "-webkit-animation-direction",
        "-moz-animation-direction",
        "-ms-animation-direction",
        "-o-animation-direction",
        "animation-direction"
    ],
    [
        "content",
        "quotes",
        "counter-reset",
        "counter-increment",
        "resize",
        "cursor",
        "-webkit-user-select",
        "-moz-user-select",
        "-ms-user-select",
        "user-select",
        "nav-index",
        "nav-up",
        "nav-right",
        "nav-down",
        "nav-left",
        "-moz-tab-size",
        "-o-tab-size",
        "tab-size",
        "-webkit-hyphens",
        "-moz-hyphens",
        "hyphens",
        "pointer-events"
    ]
]

顏色

顏色16進制用小寫字母；

顏色16進制盡量用簡寫。

/* not good */
.element {
    color: #ABCDEF;
    background-color: #001122;
}

/* good */
.element {
    color: #abcdef;
    background-color: #012;
}

屬性簡寫

屬性簡寫需要你非常清楚屬性值的正確順序，而且在大多數(shù)情況下并不需要設(shè)置屬性簡寫中包含的所有值，所以建議盡量分開聲明會更加清晰；

margin?和?padding?相反，需要使用簡寫；

常見的屬性簡寫包括：

• font
• background
• transition
• animation

/* not good */
.element {
    transition: opacity 1s linear 2s;
}

/* good */
.element {
    transition-delay: 2s;
    transition-timing-function: linear;
    transition-duration: 1s;
    transition-property: opacity;
}

媒體查詢

盡量將媒體查詢的規(guī)則靠近與他們相關(guān)的規(guī)則，不要將他們一起放到一個獨立的樣式文件中，或者丟在文檔的最底部，這樣做只會讓大家以后更容易忘記他們。

.element {
    ...
}

.element-avatar{
    ...
}

@media (min-width: 480px) {
    .element {
        ...
    }

    .element-avatar {
        ...
    }
}

SCSS相關(guān)

提交的代碼中不要有?@debug；

聲明順序：

• @extend
• 不包含?@content?的?@include
• 包含?@content?的?@include
• 自身屬性
• 嵌套規(guī)則

@import?引入的文件不需要開頭的'_'和結(jié)尾的'.scss'；

嵌套最多不能超過5層；

@extend?中使用placeholder選擇器；

去掉不必要的父級引用符號'&'。

/* not good */
@import "_dialog.scss";

/* good */
@import "dialog";

/* not good */
.fatal {
    @extend .error;
}

/* good */
.fatal {
    @extend %error;
}

/* not good */
.element {
    & > .dialog {
        ...
    }
}

/* good */
.element {
    > .dialog {
        ...
    }
}

雜項

不允許有空的規(guī)則；

元素選擇器用小寫字母；

去掉小數(shù)點前面的0；

去掉數(shù)字中不必要的小數(shù)點和末尾的0；

屬性值'0'后面不要加單位；

同個屬性不同前綴的寫法需要在垂直方向保持對齊，具體參照右邊的寫法；

無前綴的標準屬性應(yīng)該寫在有前綴的屬性后面；

不要在同個規(guī)則里出現(xiàn)重復(fù)的屬性，如果重復(fù)的屬性是連續(xù)的則沒關(guān)系；

不要在一個文件里出現(xiàn)兩個相同的規(guī)則；

用?border: 0;?代替?border: none;；

選擇器不要超過4層（在scss中如果超過4層應(yīng)該考慮用嵌套的方式來寫）；

發(fā)布的代碼中不要有?@import；

盡量少用'*'選擇器。

/* not good */
.element {
}

/* not good */
LI {
    ...
}

/* good */
li {
    ...
}

/* not good */
.element {
    color: rgba(0, 0, 0, 0.5);
}

/* good */
.element {
    color: rgba(0, 0, 0, .5);
}

/* not good */
.element {
    width: 50.0px;
}

/* good */
.element {
    width: 50px;
}

/* not good */
.element {
    width: 0px;
}

/* good */
.element {
    width: 0;
}

/* not good */
.element {
    border-radius: 3px;
    -webkit-border-radius: 3px;
    -moz-border-radius: 3px;

    background: linear-gradient(to bottom, #fff 0, #eee 100%);
    background: -webkit-linear-gradient(top, #fff 0, #eee 100%);
    background: -moz-linear-gradient(top, #fff 0, #eee 100%);
}

/* good */
.element {
    -webkit-border-radius: 3px;
       -moz-border-radius: 3px;
            border-radius: 3px;

    background: -webkit-linear-gradient(top, #fff 0, #eee 100%);
    background:    -moz-linear-gradient(top, #fff 0, #eee 100%);
    background:         linear-gradient(to bottom, #fff 0, #eee 100%);
}

/* not good */
.element {
    color: rgb(0, 0, 0);
    width: 50px;
    color: rgba(0, 0, 0, .5);
}

/* good */
.element {
    color: rgb(0, 0, 0);
    color: rgba(0, 0, 0, .5);
}