30 Seconds of CSS[译][践]

文章来源于 30 Seconds of CSS ，一些很有用的css片段，30秒内你就能理解！

代码相对简单，html，css，js代码都放置一起，具体效果还是亲自动手才能学真知！也可以参考译文！

Layout（布局）

重置box-sizing: border-box

Box-sizing reset

<div class="box">border-box</div>
<div class="box content-box">content-box</div>

html {
  box-sizing: border-box;
}
*,
*::before,
*::after {
  box-sizing: inherit;
}
.box {
  display: inline-block;
  width: 150px;
  height: 150px;
  padding: 10px;
  background: tomato;
  color: white;
  border: 10px solid red;
}
.content-box {
  box-sizing: content-box;
}

清除浮动

Clearfix

<div class="clearfix">
  <div class="floated">float a</div>
  <div class="floated">float b</div>
  <div class="floated">float c</div>
</div>

.clearfix::after {
  content: '';
  display: block;
  clear: both;
}
.floated {
  float: left;
}

响应式布局等比例宽高元素

Constant width to height ratio

<div class="constant-width-to-height-ratio"></div>
.constant-width-to-height-ratio {
  background: #333;
  width: 50%;
}
.constant-width-to-height-ratio::before {
  content: '';
  padding-top: 100%;
  float: left;
}
.constant-width-to-height-ratio::after {
  content: '';
  display: block;
  clear: both;
}

用display: table居中

Display table centering

<div class="container">
  <div class="center"><span>Centered content</span></div>
</div>
.container {
  border: 1px solid #333;
  height: 250px;
  width: 250px;
}
.center {
  display: table;
  height: 100%;
  width: 100%;
}
.center > span {
  display: table-cell;
  text-align: center;
  vertical-align: middle;
}

在父元素均匀分布子元素

Evenly distributed children

<div class="evenly-distributed-children">
  <p>Item1</p>
  <p>Item2</p>
  <p>Item3</p>
</div>
.evenly-distributed-children {
  display: flex;
  justify-content: space-between;
}

用display: flex水平垂直居中

Flexbox centering

<div class="flexbox-centering"><div class="child">Centered content.</div></div>
.flexbox-centering {
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100px;
}

用display: grid水平垂直居中

Grid centering

<div class="grid-centering"><div class="child">Centered content.</div></div>
.grid-centering {
  display: grid;
  justify-content: center;
  align-items: center;
  height: 100px;
}

在flex布局中让最后元素自动充满剩下区域

Last item with remaining available height

<div class="container">
  <div>Div 1</div>
  <div>Div 2</div>
  <div>Div 3</div>
</div>
html,
body {
  height: 100%;
  margin: 0;
}
.container {
  height: 100%;
  display: flex;
  flex-direction: column;
}
.container > div:last-child {
  background-color: tomato;
  flex: 1;
}

在不知道元素宽高的情况下，利用Transform水平垂直居中元素

Transform centering

<div class="parent"><div class="child">Centered content</div></div>
.parent {
  border: 1px solid #333;
  height: 250px;
  position: relative;
  width: 250px;
}
.child {
  left: 50%;
  position: absolute;
  top: 50%;
  transform: translate(-50%, -50%);
  text-align: center;
}

超出的文本用...代替

Truncate text

<p class="truncate-text">If I exceed one line's width, I will be truncated.</p>
.truncate-text {
  overflow: hidden;
  white-space: nowrap;
  text-overflow: ellipsis;
  width: 200px;
}

Visual（视觉）

用纯css画圆圈

Circle

<div class="circle"></div>
.circle {
  border-radius: 50%;
  width: 2rem;
  height: 2rem;
  background: #333;
}

自定义滚动条样式

Custom scrollbar

<div class="custom-scrollbar">
  <p>
    Lorem ipsum dolor sit amet consectetur adipisicing elit.<br />
    Iure id exercitationem nulla qui repellat laborum vitae, <br />
    molestias tempora velit natus. Quas, assumenda nisi. <br />
    Quisquam enim qui iure, consequatur velit sit?
  </p>
</div>
.custom-scrollbar {
  height: 70px;
  overflow-y: scroll;
}
/* To style the document scrollbar, remove `.custom-scrollbar` */
.custom-scrollbar::-webkit-scrollbar {
  width: 8px;
}
.custom-scrollbar::-webkit-scrollbar-track {
  box-shadow: inset 0 0 6px rgba(0, 0, 0, 0.3);
  border-radius: 10px;
}
.custom-scrollbar::-webkit-scrollbar-thumb {
  border-radius: 10px;
  box-shadow: inset 0 0 6px rgba(0, 0, 0, 0.5);
}

自定义文本选择样式

Custom text selection

<p class="custom-text-selection">Select some of this text.</p>
::selection {
  background: aquamarine;
  color: black;
}
.custom-text-selection::selection {
  background: deeppink;
  color: white;
}

根据自身颜色动态地变化阴影颜色

Dynamic shadow

<div class="dynamic-shadow"></div>
.dynamic-shadow {
  position: relative;
  width: 10rem;
  height: 10rem;
  background: linear-gradient(75deg, #6d78ff, #00ffb8);
  z-index: 1;
}
.dynamic-shadow::after {
  content: '';
  width: 100%;
  height: 100%;
  position: absolute;
  background: inherit;
  top: 0.5rem;
  filter: blur(0.4rem);
  opacity: 0.7;
  z-index: -1;
}

烛刻文字

Etched text

<p class="etched-text">I appear etched into the background.</p>
.etched-text {
  text-shadow: 0 2px white;
  font-size: 1.5rem;
  font-weight: bold;
  color: #b8bec5;
}

用object-fit和object-position 代替 background-size和background-position

Fit image in container

<img class="image image-contain" src="https://picsum.photos/600/200" />
<img class="image image-cover" src="https://picsum.photos/600/200" />
.image {
  background: #34495e;
  border: 1px solid #34495e;
  width: 200px;
  height: 200px;
}
.image-contain {
  object-fit: contain;
  object-position: center;
}
.image-cover {
  object-fit: cover;
  object-position: right top;
}

渐变色文本

Gradient text

<p class="gradient-text">Gradient text</p>
.gradient-text {
  background: -webkit-linear-gradient(pink, red);
  -webkit-text-fill-color: transparent;
  -webkit-background-clip: text;
}

边际线边框

Hairline border

<div class="hairline-border">text</div>
.hairline-border {
  box-shadow: 0 0 0 1px;
}
@media (min-resolution: 2dppx) {
  .hairline-border {
    box-shadow: 0 0 0 0.5px;
  }
}
@media (min-resolution: 3dppx) {
  .hairline-border {
    box-shadow: 0 0 0 0.33333333px;
  }
}
@media (min-resolution: 4dppx) {
  .hairline-border {
    box-shadow: 0 0 0 0.25px;
  }
}

:not选择器

:not selector

<ul class="css-not-selector-shortcut">
  <li>One</li>
  <li>Two</li>
  <li>Three</li>
  <li>Four</li>
</ul>
.css-not-selector-shortcut {
  display: flex;
}
ul {
  padding-left: 0;
}
li {
  list-style-type: none;
  margin: 0;
  padding: 0 0.75rem;
}
li:not(:last-child) {
  border-right: 2px solid #d2d5e4;
}

在屏幕上消失的元素

Offscreen

关键词：可绑定js事件对象，更合适对盲人需要提供额外的信息，相对于display:none它能提供盲人设备信息，相对于visibility: hidden，它不占用物理空间

<a class="button" href="http://pantswebsite.com">
  Learn More <span class="offscreen"> about pants</span>
</a>
.offscreen {
  border: 0;
  clip: rect(0 0 0 0);
  height: 1px;
  margin: -1px;
  overflow: hidden;
  padding: 0;
  position: absolute;
  width: 1px;
}

梯度隐藏元素以指示需要滚动获取更多内容

Overflow scroll gradient

<div class="overflow-scroll-gradient">
  <div class="overflow-scroll-gradient__scroller">
    Lorem ipsum dolor sit amet consectetur adipisicing elit. <br />
    Iure id exercitationem nulla qui repellat laborum vitae, <br />
    molestias tempora velit natus. Quas, assumenda nisi. <br />
    Quisquam enim qui iure, consequatur velit sit? <br />
    Lorem ipsum dolor sit amet consectetur adipisicing elit.<br />
    Iure id exercitationem nulla qui repellat laborum vitae, <br />
    molestias tempora velit natus. Quas, assumenda nisi. <br />
    Quisquam enim qui iure, consequatur velit sit?
  </div>
</div>
.overflow-scroll-gradient {
  position: relative;
}
.overflow-scroll-gradient::after {
  content: '';
  position: absolute;
  bottom: 0;
  width: 240px;
  height: 25px;
  background: linear-gradient(
    rgba(255, 255, 255, 0.001),
    white
  ); /* transparent keyword is broken in Safari */
  pointer-events: none;
}
.overflow-scroll-gradient__scroller {
  overflow-y: scroll;
  background: white;
  width: 240px;
  height: 200px;
  padding: 15px;
  line-height: 1.2;
}

漂亮文本下划线

Pretty text underline

<p class="pretty-text-underline">Pretty text underline without clipping descending letters.</p>
.pretty-text-underline {
  display: inline;
  text-shadow: 1px 1px #f5f6f9, -1px 1px #f5f6f9, -1px -1px #f5f6f9, 1px -1px #f5f6f9;
  background-image: linear-gradient(90deg, currentColor 100%, transparent 100%);
  background-position: bottom;
  background-repeat: no-repeat;
  background-size: 100% 1px;
}
.pretty-text-underline::-moz-selection {
  background-color: rgba(0, 150, 255, 0.3);
  text-shadow: none;
}
.pretty-text-underline::selection {
  background-color: rgba(0, 150, 255, 0.3);
  text-shadow: none;
}

重置所有样式

Reset all styles

<div class="reset-all-styles">
  <h5>Title</h5>
  <p>
    Lorem ipsum dolor sit amet consectetur adipisicing elit. Iure id exercitationem nulla qui
    repellat laborum vitae, molestias tempora velit natus. Quas, assumenda nisi. Quisquam enim qui
    iure, consequatur velit sit?
  </p>
</div>
.reset-all-styles {
  all: initial;
}

用svg制作锋利的锯齿形状

Shape separator

<div class="shape-separator"></div>
.shape-separator {
  position: relative;
  height: 48px;
  background: #333;
}
.shape-separator::after {
  content: '';
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 12'%3E%3Cpath d='m12 0l12 12h-24z' fill='%23fff'/%3E%3C/svg%3E");
  position: absolute;
  width: 100%;
  height: 12px;
  bottom: 0;
}

使用系统字体效果

System font stack

<p class="system-font-stack">This text uses the system font.</p>
.system-font-stack {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen-Sans, Ubuntu,
    Cantarell, 'Helvetica Neue', Helvetica, Arial, sans-serif;
}

三角形

Triangle

<div class="triangle"></div>
.triangle {
  width: 0;
  height: 0;
  border-top: 20px solid #333;
  border-left: 20px solid transparent;
  border-right: 20px solid transparent;
}

构建交替的斑马线列表

Zebra striped list

<ul>
  <li>Item 01</li>
  <li>Item 02</li>
  <li>Item 03</li>
  <li>Item 04</li>
  <li>Item 05</li>
</ul>
li:nth-child(odd) {
  background-color: #eee;
}

Animation（动画）

弹跳的加载动画

Bouncing loader

<div class="bouncing-loader">
  <div></div>
  <div></div>
  <div></div>
</div>
@keyframes bouncing-loader {
  to {
    opacity: 0.1;
    transform: translate3d(0, -1rem, 0);
  }
}
.bouncing-loader {
  display: flex;
  justify-content: center;
}
.bouncing-loader > div {
  width: 1rem;
  height: 1rem;
  margin: 3rem 0.2rem;
  background: #8385aa;
  border-radius: 50%;
  animation: bouncing-loader 0.6s infinite alternate;
}
.bouncing-loader > div:nth-child(2) {
  animation-delay: 0.2s;
}
.bouncing-loader > div:nth-child(3) {
  animation-delay: 0.4s;
}

用:hover做按钮交互效果

Button border animation

<div class="button-border"><button class="button">Submit</button></div>
.button {
  background-color: #c47135;
  border: none;
  color: #ffffff;
  outline: none;
  padding: 12px 40px 10px;
  position: relative;
}
.button:before,
.button:after {
  border: 0 solid transparent;
  transition: all 0.25s;
  content: '';
  height: 24px;
  position: absolute;
  width: 24px;
}
.button:before {
  border-top: 2px solid #c47135;
  left: 0px;
  top: -5px;
}
.button:after {
  border-bottom: 2px solid #c47135;
  bottom: -5px;
  right: 0px;
}
.button:hover {
  background-color: #c47135;
}
.button:hover:before,
.button:hover:after {
  height: 100%;
  width: 100%;
}

圆圈加载loading

Donut spinner

<div class="donut"></div>
@keyframes donut-spin {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(360deg);
  }
}
.donut {
  display: inline-block;
  border: 4px solid rgba(0, 0, 0, 0.1);
  border-left-color: #7983ff;
  border-radius: 50%;
  width: 30px;
  height: 30px;
  animation: donut-spin 1.2s linear infinite;
}

更容易的变量

Easing variables

<div class="easing-variables">Hover</div>
:root {
  /* Place variables in here to use globally */
}
.easing-variables {
  --ease-in-quad: cubic-bezier(0.55, 0.085, 0.68, 0.53);
  --ease-in-cubic: cubic-bezier(0.55, 0.055, 0.675, 0.19);
  --ease-in-quart: cubic-bezier(0.895, 0.03, 0.685, 0.22);
  --ease-in-quint: cubic-bezier(0.755, 0.05, 0.855, 0.06);
  --ease-in-expo: cubic-bezier(0.95, 0.05, 0.795, 0.035);
  --ease-in-circ: cubic-bezier(0.6, 0.04, 0.98, 0.335);
  --ease-out-quad: cubic-bezier(0.25, 0.46, 0.45, 0.94);
  --ease-out-cubic: cubic-bezier(0.215, 0.61, 0.355, 1);
  --ease-out-quart: cubic-bezier(0.165, 0.84, 0.44, 1);
  --ease-out-quint: cubic-bezier(0.23, 1, 0.32, 1);
  --ease-out-expo: cubic-bezier(0.19, 1, 0.22, 1);
  --ease-out-circ: cubic-bezier(0.075, 0.82, 0.165, 1);
  --ease-in-out-quad: cubic-bezier(0.455, 0.03, 0.515, 0.955);
  --ease-in-out-cubic: cubic-bezier(0.645, 0.045, 0.355, 1);
  --ease-in-out-quart: cubic-bezier(0.77, 0, 0.175, 1);
  --ease-in-out-quint: cubic-bezier(0.86, 0, 0.07, 1);
  --ease-in-out-expo: cubic-bezier(1, 0, 0, 1);
  --ease-in-out-circ: cubic-bezier(0.785, 0.135, 0.15, 0.86);
  display: inline-block;
  width: 75px;
  height: 75px;
  padding: 10px;
  color: white;
  line-height: 50px;
  text-align: center;
  background: #333;
  transition: transform 1s var(--ease-out-quart);
}
.easing-variables:hover {
  transform: rotate(45deg);
}

动画效果从0到未知高度

Height transition

<div class="trigger">
  Hover me to see a height transition.
  <div class="el">content</div>
</div>
.el {
  transition: max-height 0.5s;
  overflow: hidden;
  max-height: 0;
}
.trigger:hover > .el {
  max-height: var(--max-height);
}
var el = document.querySelector('.el')
var height = el.scrollHeight
el.style.setProperty('--max-height', height + 'px')

交互阴影box动画

Hover Shadow Box Animation

<p class="hover-shadow-box-animation">Box it!</p>
.hover-shadow-box-animation {
  display: inline-block;
  vertical-align: middle;
  transform: perspective(1px) translateZ(0);
  box-shadow: 0 0 1px transparent;
  margin: 10px;
  transition-duration: 0.3s;
  transition-property: box-shadow, transform;
}
.hover-shadow-box-animation:hover,
.hover-shadow-box-animation:focus,
.hover-shadow-box-animation:active {
  box-shadow: 1px 10px 10px -10px rgba(0, 0, 24, 0.5);
  transform: scale(1.2);
}

下划线交互动画

Hover underline animation

<p class="hover-underline-animation">Hover this text to see the effect!</p>
.hover-underline-animation {
  display: inline-block;
  position: relative;
  color: #0087ca;
}
.hover-underline-animation::after {
  content: '';
  position: absolute;
  width: 100%;
  transform: scaleX(0);
  height: 2px;
  bottom: 0;
  left: 0;
  background-color: #0087ca;
  transform-origin: bottom right;
  transition: transform 0.25s ease-out;
}
.hover-underline-animation:hover::after {
  transform: scaleX(1);
  transform-origin: bottom left;
}

Interactivity（交互）

不能选中

Disable selection

<p>You can select me.</p>
<p class="unselectable">You can't select me!</p>
.unselectable {
  user-select: none;
}

:focus-within的应用

如果子元素聚焦，则改变父子的样式

Focus Within

<div class="focus-within">
  <form>
    <label for="given_name">Given Name:</label> <input id="given_name" type="text" /> <br />
    <label for="family_name">Family Name:</label> <input id="family_name" type="text" />
  </form>
</div>
form {
  border: 3px solid #2d98da;
  color: #000000;
  padding: 4px;
}
form:focus-within {
  background: #f7b731;
  color: #000000;
}

鼠标悬停效果跟踪

Mouse cursor gradient tracking

<button class="mouse-cursor-gradient-tracking"><span>Hover me</span></button>
.mouse-cursor-gradient-tracking {
  position: relative;
  background: #7983ff;
  padding: 0.5rem 1rem;
  font-size: 1.2rem;
  border: none;
  color: white;
  cursor: pointer;
  outline: none;
  overflow: hidden;
}
.mouse-cursor-gradient-tracking span {
  position: relative;
}
.mouse-cursor-gradient-tracking::before {
  --size: 0;
  content: '';
  position: absolute;
  left: var(--x);
  top: var(--y);
  width: var(--size);
  height: var(--size);
  background: radial-gradient(circle closest-side, pink, transparent);
  transform: translate(-50%, -50%);
  transition: width 0.2s ease, height 0.2s ease;
}
.mouse-cursor-gradient-tracking:hover::before {
  --size: 200px;
}
var btn = document.querySelector('.mouse-cursor-gradient-tracking')
btn.onmousemove = function(e) {
  var x = e.pageX - btn.offsetLeft - btn.offsetParent.offsetLeft
  var y = e.pageY - btn.offsetTop - btn.offsetParent.offsetTop
  btn.style.setProperty('--x', x + 'px')
  btn.style.setProperty('--y', y + 'px')
}

悬浮弹出菜单

Popout menu

<div class="reference" tabindex="0"><div class="popout-menu">Popout menu</div></div>
.reference {
  position: relative;
  background: tomato;
  width: 100px;
  height: 100px;
}
.popout-menu {
  position: absolute;
  visibility: hidden;
  left: 100%;
  background: #333;
  color: white;
  padding: 15px;
}
.reference:hover > .popout-menu,
.reference:focus > .popout-menu,
.reference:focus-within > .popout-menu {
  visibility: visible;
}

用纯css控制子兄弟（退出）的效果

Sibling fade

<div class="sibling-fade">
  <span>Item 1</span> <span>Item 2</span> <span>Item 3</span> <span>Item 4</span>
  <span>Item 5</span> <span>Item 6</span>
</div>
span {
  padding: 0 1rem;
  transition: opacity 0.2s;
}
.sibling-fade:hover span:not(:hover) {
  opacity: 0.5;
}

开关按钮

Toggle switch

<input type="checkbox" id="toggle" class="offscreen" /> <label for="toggle" class="switch"></label>
.switch {
  position: relative;
  display: inline-block;
  width: 40px;
  height: 20px;
  background-color: rgba(0, 0, 0, 0.25);
  border-radius: 20px;
  transition: all 0.3s;
}
.switch::after {
  content: '';
  position: absolute;
  width: 18px;
  height: 18px;
  border-radius: 18px;
  background-color: white;
  top: 1px;
  left: 1px;
  transition: all 0.3s;
}
input[type='checkbox']:checked + .switch::after {
  transform: translateX(20px);
}
input[type='checkbox']:checked + .switch {
  background-color: #7983ff;
}
.offscreen {
  position: absolute;
  left: -9999px;
}

Other（其他）

数学计算样式值

Calc()

<div class="box-example"></div>
.box-example {
  height: 280px;
  background: #222 url('https://image.ibb.co/fUL9nS/wolf.png') no-repeat;
  background-position: calc(100% - 20px) calc(100% - 20px);
}

计数器复位

Counter

<ul>
  <li>List item</li>
  <li>List item</li>
  <li>
    List item
    <ul>
      <li>List item</li>
      <li>List item</li>
      <li>List item</li>
    </ul>
  </li>
</ul>

自定义变量

Custom variables

<p class="custom-variables">CSS is awesome!</p>
:root {
  /* Place variables within here to use the variables globally. */
}
.custom-variables {
  --some-color: #da7800;
  --some-keyword: italic;
  --some-size: 1.25em;
  --some-complex-value: 1px 1px 2px whitesmoke, 0 0 1em slategray, 0 0 0.2em slategray;
  color: var(--some-color);
  font-size: var(--some-size);
  font-style: var(--some-keyword);
  text-shadow: var(--some-complex-value);
}