* {
  box-sizing: border-box;
}

body {
  height: 100vh;
  margin: 0;
  background-color: #6e59e0;
  display: flex;
  justify-content: center;
  align-items: center;
}

.app {
  height: 50px;
  position: relative;
  overflow: hidden;
}

.btn {
  border: none;
  height: 100%;
  width: 50px;
  cursor: pointer;
  position: absolute;
  right: 0;
  top: 0;
  background-color: #fff;
}

.input {
  width: 50px;
  height: 50px;
  border: none;
  padding: 15px;
  background-color: #fff;
  transition: all 0.3s;
  font-size: 18px;
}

.input.active {
  width: 250px;
}

.btn:focus,
.input:focus {
  outline: none;
}

i {
  font-size: 20px;
}