@import url("https://fonts.googleapis.com/css2?family=Montserrat:wght@400;500&display=swap");

:root {
  --default-color: hsl(200, 4%, 60%);
  --active-color: hsl(200, 70%, 56%);
  --error-color: hsl(353, 64%, 53%);
  --border-color: hsl(200, 4%, 64%);
  --text-color: hsl(200, 4%, 24%);
  --body-color: hsl(0, 0%, 100%);

  --body-font: "Montserrat", sans-serif;
  --normal-font-size: 1rem;
  --small-font-size: .813rem;
  --smaller-font-size: .75rem;
}

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

body,
input {
  font-size: var(--normal-font-size);
  font-family: var(--body-font);
  color: var(--text-color);
}

body {
  background-color: var(--body-color);
}

.container {
  height: 100vh;
  margin-inline: 1.5rem;
  display: grid;
  place-items: center;
}

.form {
  width: 100%;
  max-width: 340px;
}

.form__field {
  position: relative;
}

.form__input {
  width: 100%;
  border: 3px solid var(--default-color);
  padding: 1.4rem 1.4rem 1.4rem 4.5rem;
  border-radius: 4rem;
  outline: none;
  font-weight: 500;
  transition: border-color .4s, box-shadow .4s;
}

.form__input::placeholder {
  color: var(--text-color);
}

.form__label {
  position: absolute;
  left: 1.5rem;
  top: -.65rem;
  background-color: var(--body-color);
  padding: 2px;
  font-size: var(--small-font-size);
  font-weight: 500;
}

.form__icon {
  height: max-content;
  font-size: 1.5rem;
  position: absolute;
  left: 1.5rem;
  top: 0;
  bottom: 0;
  margin-block: auto;
}

.form__field::after {
  content: "";
  position: absolute;
  height: 28px;
  border: 1px solid var(--border-color);
  left: 3.75rem;
  top: 0;
  bottom: 0;
  margin-block: auto;
}

.form__error {
  position: absolute;
  left: 1.5rem;
  bottom: -1.5rem;
  display: flex;
  align-items: center;
  column-gap: .25rem;
  color: var(--error-color);
  opacity: 0;
  pointer-events: none;
  transition: opacity .4s;
}

.form__error i {
  font-size: 1rem;
}

.form__error span {
  font-size: var(--smaller-font-size);
  font-weight: 500;
}

.form__input:focus,
.valid .form__input {
  border-color: var(--active-color);
  box-shadow: 0 8px 24px hsla(200, 70%, 56%, .3);
}

.invalid .form__input {
  border-color: var(--error-color);
  box-shadow: 0 8px 24px hsla(353, 64%, 53%, .3);
}

.invalid .form__error {
  opacity: 1;
}