style.css

@import url("https://fonts.googleapis.com/css2?family=Poppins:wght@300;400;700&display=swap");

* {
  margin: 0;
  padding: 0;
}

body {
  font-family: "Poppins", sans-serif;
  background: linear-gradient(to top, #323232, rgb(0, 150, 90));
}

#container {
  display: grid;
  justify-content: center;
  align-content: center;
  height: 100vh;
}

#container > h1 {
  text-align: center;
}

#input > #input-texto {
  width: 30em;
  height: 2em;
  margin-bottom: 10px;
  border: solid #111 1px;
}

#input > #converter {
  font-family: "Poppins";
  width: 8.5em;
  height: 2.2em;
  border: solid #111 1px;
}

#input > #converter:hover {
  background-color: #888;
}

#input-texto::placeholder {
  font-family: "Poppins";
  color: #000;
}

#div-result {
  position: relative;
  left: 1px;
  background-color: #fff;
  min-height: 4vh;
  width: 520px;
}