index.css

html, body {
  height: 100%;
  width: 100%;
}

* {
  margin: 0;
  padding: 0;
}

#app {
  height: 100%;
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding-top: 3vh;
  box-sizing: border-box;
}

/*** 按钮 ***/
.btn {
  display: inline-block;
  margin-bottom: 10px;
  background: #3498db;
  border-radius: 28px;
  font-family: Arial;
  color: #ffffff;
  font-size: 8px;
  padding: 10px 20px 10px 20px;
  text-decoration: none;
  cursor: pointer;
}
.btn:hover {
  background: #3cb0fd;
  background-image: linear-gradient(to bottom, #3cb0fd, #3498db);
  text-decoration: none;
}
.btn+.btn {
  margin-left: 10px;
}
.center {
  display: flex;
  justify-content: center;
  align-items: center;
  margin-bottom: 10px;
}

.wrap {
  padding: 44px;
  border: 1px solid #ccc;
  border-radius: 10px;
}

/*** 卡片容器 ***/
.container {
  position: relative;
  width: 320px;
  height: 320px;
  max-width: 500px;
  /* 不兼容 */
  /* aspect-ratio: 16/16; */
}

/*** 卡片 ***/
.card-wrap {
  position: absolute;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 40px;
  width: 40px;
  font-size: 30px;
  cursor: pointer;
  transition: all 0.2s;
  user-select: none;
}

.card {
  display: flex;
  justify-content: center;
  align-items: center;
  width: calc(100% - 2px);
  height:calc(100% - 2px);
  border: 1px solid rgb(100, 100, 100);
  border-radius: 10px;
  background-color: #ccc;
}
.card span {
  opacity: 0.5;
  font-size: 24px;
}
.is-allow {
  background-color: white;
}
.is-allow span {
  opacity: 1;
}
/*** 卡片动画 ***/
@keyframes scaleDraw {
  0% {
    transform: scale(1.1);
  }
  20% {
    transform: scale(1);
  }
  100% {
    transform: scale(0);
  }
}

/*** 卡槽 ***/
.card-slot {
  margin-top: 20px;
  padding: 10px 20px 10px 20px;
  border: 1px solid #ccc;
  height: 40px;
  width: 280px;
  border-radius: 10px;
}