style.css

* {
  margin: 0;
  padding: 0;
  outline: 0;
  box-sizing: border-box;
}

body {
  background: #392F5A;
  color: #fff;
  -webkit-font-smoothing: antialiased;
}

body, input, button {
  font-family: 'Nunito', sans-serif;
  font-size: 16px;
}

h1, h2, h3, h4, h5, h6 {
  font-weight: 600;
}

button {
  cursor: pointer;
}

main {
  height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

main h1 {
  font-size: 40px;
  margin-bottom: 30px;
  letter-spacing: 10px;
  font-weight: 700;
  text-align: center;
}

main p {
  margin: 50px 20px 0;
  font-size: 24px;
  text-align: center;
}

main p strong:first-child {
  color: #EEC643;
}

main p strong {
  font-size: 28px;
}

form {
  display: flex;
  flex-direction: column;
  align-items: center;
  position: relative;
  width: 100%;
}

form div {
  display: flex;
}

form div input {
  height: 55px;
  width: 180px;
  border: 0;
  background: #03002744;
  border-radius: 10px 0 0 10px;
  color: #fff;
  font-size: 24px;
  padding: 18px;
}

form div button {
  height: 55px;
  border: 0;
  border-radius: 0 10px 10px 0;
  width: 120px;
  font-size: 18px;
  font-weight: 700;
  color: #030027;
  cursor: not-allowed;
}

form span {
  position: absolute;
  height: 24px;
  background: #EE6352;
  padding: 8px;
  border-radius: 4px;
  bottom: -35px;
  margin-top: 8px;
  font-size: 14px;
  display: none;
}

.input-error {
  border: 1px solid #EE6352;
  border-right: 0;
  box-shadow: 0 0 2px 1px #EE635288;
}

.error {
  display: flex;
  align-items: center;
  justify-content: center;
}