*{
  margin: 0;
  padding:0;
}

body{
  width: 100vw;
  height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: space-around;
  align-items: center;
  background-color: #dde1e7;
}
.container{
  width: 800px;
  height: 300px;
  background-color: #eee;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 25px;
  border-radius: 10px;
  box-shadow: -3px -3px 7px #ffffff73,
              2px 2px 5px #5e6879e0;
}

.key > input[type="button"]{
  min-width: 50px;
  height: 50px;
  margin: 10px;
  padding: 10px;
  border: none;
  border-radius: 5px;
  box-shadow: -3px -3px 7px #ffffff73,
              2px 2px 5px rgba(93, 103, 121, 0.2);
  color: grey;
  font-size: 18px;
  background-color: #dde1ef;
}

.key > input[value="SPACE"]{
  width: 400px;
}


/* 获得焦点时的样式 */
.key > input:focus{
  font-size: 16px;
  color: #4561ff;
  box-shadow: inset -3px -3px 7px #ffffff73,
              inset 2px 2px 5px rgba(94, 104, 121, 0.2);
  outline: none;
}