style.css

@import url("https://fonts.googleapis.com/css2?family=Mochiy+Pop+P+One&display=swap");

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Mochiy Pop P One", sans-serif;
}
body {
  background: rgb(238, 174, 202);
  background: radial-gradient(
    circle,
    rgba(238, 174, 202, 0.918) 2%,
    rgba(148, 188, 233, 0.938) 100%
  );
  color: rgba(0, 0, 0, 0.788);
  display: flex;
  justify-content: center;
  margin: 7rem;
}
.container {
  height: 60vh;
  width: 70vw;
  background-color: #fff;
  box-shadow: 2px -2px 70px rgba(0, 0, 0, 0.836);
  border-radius: 10px;
}
.container h1 {
  text-align: center;
  padding-top: 2rem;
  padding-bottom: 3rem;
  color: rgba(0, 0, 0, 0.788);
}
.display {
  display: flex;
  justify-content: center;
}
.display .celsius {
  margin-right: 2rem;
  text-align: center;
}
.celsius label {
  font-size: 1.3rem;
}
.celsius input {
  font-size: 1.5rem;
  margin-top: 1rem;
  padding: 10px 30px;
  text-align: center;
}
.display .fahrenheit {
  margin-right: 2rem;
  text-align: center;
}
.fahrenheit label {
  font-size: 1.3rem;
}
.fahrenheit input {
  font-size: 1.5rem;
  margin-top: 1rem;
  padding: 10px 30px;
  text-align: center;
}

@media only screen and (max-width: 500px) {
  body {
    margin: 3rem;
    overflow-y: hidden;
  }
  .container h1 {
    font-size: 1.7rem;
    padding-top: 1rem;
    padding-bottom: 2rem;
  }
  .display {
    display: flex;
    flex-direction: column;
  }
  .celsius input {
    width: 200px;
    outline: 0px;
    border: 1px solid #000;
    margin-bottom: 2rem;
    margin-left: 1.5rem;
  }
  .fahrenheit input {
    width: 200px;
    outline: 0px;
    border: 1px solid #000;
    margin-bottom: 2rem;
    margin-left: 1.5rem;
  }
}