<div class="container">
  <div class="div1">Div 1</div>
  <div class="div2">Div 2</div>
</div>

.container {
  display: flex;
  justify-content: center; /* 水平居中对齐 */
  align-items: center; /* 垂直居中对齐 */
}

.div1, .div2 {
  width: 100px;
  height: 100px;
  background-color: #ccc;
}

<div class="container">
  <div class="div1">Div 1</div>
  <div class="div2">Div 2</div>
</div>

.container {
  display: grid;
  place-items: center; /* 水平和垂直居中对齐 */
}

.div1, .div2 {
  width: 100px;
  height: 100px;
  background-color: #ccc;
}

<div class="container">
  <div class="div1">Div 1</div>
  <div class="div2">Div 2</div>
</div>

.container {
  position: relative;
  width: 300px;
  height: 200px;
  background-color: #f0f0f0;
}

.div1, .div2 {
  position: absolute;
  width: 100px;
  height: 100px;
  background-color: #ccc;
}

.div1 {
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%); /* 水平和垂直居中对齐 */
}

.div2 {
  top: 0;
  right: 0;
}