「CSS」小知识 不断更新

@规则

• link 导入的样式会在页面加载时同时加载，@import 导入的样式需等页面加载完成后再加载；

实现垂直居中

<div class="container">
  <div class="item" style="width: 100px; height: 100px; background: #999;">
    块状元素
  </div>
</div>

<div class="container">
  <div class="item">不定高宽的块状元素</div>
</div>

<div class="container">
  <span class="item">行内元素</span>
</div>

.item {
  padding: 1rem;
  border: 1px solid #999;
}

.container {
  height: 12rem;
  background: #ccc;
  margin: 1rem;
}

绝对定位

.container {
  position: relative;
}

.item {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

flex

.container {
  display: flex;
  justify-content: center;
  align-items: center;
}

grid

.container {
  display: grid;
  justify-content: center;
  align-content: center;
  <!-- place-items: center; 或者 place-content: center; 也可以 -->
}

flex 奇妙的方法

.container {
  display: flex;
}

.item {
  margin: auto;
}

实现左边固定 300px，右边自适应

浮动

.container {
  padding-left: 300px;
  height:300px;
}
.left,
.main {
  float: left;
  height:300px;
}
.left {
  width: 300px;
  margin-left: -300px;
  background-color: red;
}
.main {
  width: 100%;
  background-color: blue;
}

• 精简版

.aside {
    float: left;
    width: 100px;
    background: red;
}
.main {
    overflow: auto;
    background: blue;
}

flex

.container {
  display: flex;
}

.left {
  flex-basis: 300px;
  flex-shrink: 0;
}

.main {
  flex-grow: 1;
}

grid

.container {
  display: grid;
  grid-template-columns: 300px 1fr;
}

实现 loading 动画

.loading {
  display: inline-block;
  width: 5em;
  height: 5em;
  stroke-width: 0;
  stroke: currentColor;
  fill: currentColor;
  animation: rotate 2s linear infinite;
}

@keyframes rotate {
  from {
    transform: rotateZ(0deg);
  }
  to {
    transform: rotateZ(360deg);
  }
}