style.css

/* Import Google font - Poppins */
@import url("https://fonts.googleapis.com/css2?family=Poppins:wght@200;300;400;500;600;700&display=swap");
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Poppins", sans-serif;
}
body {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #00bc69;
}
:where(.container, form, .input-field, header) {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}
.container {
  background: #fff;
  padding: 30px 65px;
  border-radius: 12px;
  row-gap: 20px;
  box-shadow: 0 5px 10px rgba(0, 0, 0, 0.1);
}
.container header {
  height: 65px;
  width: 65px;
  background: #00bc69;
  color: #fff;
  font-size: 2.5rem;
  border-radius: 50%;
}
.container h4 {
  font-size: 1.25rem;
  color: #333;
  font-weight: 500;
}
form .input-field {
  flex-direction: row;
  column-gap: 10px;
}
.input-field input {
  height: 45px;
  width: 42px;
  border-radius: 6px;
  outline: none;
  font-size: 1.125rem;
  text-align: center;
  border: 1px solid #ddd;
}
.input-field input:focus {
  box-shadow: 0 1px 0 rgba(0, 0, 0, 0.1);
}
.input-field input::-webkit-inner-spin-button,
.input-field input::-webkit-outer-spin-button {
  display: none;
}
form button {
  margin-top: 25px;
  width: 100%;
  color: #fff;
  font-size: 1rem;
  border: none;
  padding: 9px 0;
  cursor: pointer;
  border-radius: 6px;
  pointer-events: none;

  background: #00bc88;
  transition: all 0.2s ease;
}

form button.active {
  background: #00bc69;
  pointer-events: auto;
}

form button:hover {
  background: #00bc69;
}