/* Design tokens */
:root {
  --blue-950: hsl(213, 96%, 18%);
  --purple-600: hsl(243, 100%, 62%);
  --blue-300: hsl(228, 100%, 84%);
  --blue-200: hsl(206, 94%, 87%);
  --red-500: hsl(354, 84%, 57%);
  --grey-500: hsl(231, 11%, 63%);
  --purple-200: hsl(229, 24%, 87%);
  --blue-100: hsl(218, 100%, 97%);
  --blue-50: hsl(231, 100%, 99%);
  --white: hsl(0, 100%, 100%);

  --font-family: "Ubuntu", sans-serif;
  --transition: 150ms ease;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font-family);
  font-size: 1rem;
  font-weight: 400;
  line-height: 1.5;
  color: var(--grey-500);
  background-color: var(--blue-50);
  background-image:
    url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23eef3ff' fill-opacity='0.6'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
}

img {
  display: block;
  max-width: 100%;
}

button,
input {
  font: inherit;
}

.layout {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1rem;
}

.form-shell {
  width: min(100%, 58.75rem);
  display: flex;
  flex-direction: column;
}

/* Sidebar */
.sidebar {
  background: url("./assets/images/bg-sidebar-mobile.svg") center / cover no-repeat;
  padding: 2rem 1.5rem 2.75rem;
  border-radius: 0.625rem 0.625rem 0 0;
}

.steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  justify-content: center;
  gap: 1.375rem;
}

.step-indicator {
  display: flex;
  align-items: center;
  gap: 0.875rem;
}

.step-indicator__number {
  width: 2.0625rem;
  height: 2.0625rem;
  display: grid;
  place-items: center;
  border: 1px solid var(--white);
  border-radius: 50%;
  color: var(--white);
  font-weight: 700;
  font-size: 0.875rem;
  flex-shrink: 0;
  transition: background-color var(--transition), color var(--transition), border-color var(--transition);
}

.step-indicator__text {
  display: none;
}

.step-indicator__label {
  display: block;
  font-size: 0.75rem;
  letter-spacing: 0.0625rem;
  text-transform: uppercase;
  color: var(--blue-200);
}

.step-indicator__name {
  display: block;
  font-size: 0.875rem;
  font-weight: 700;
  letter-spacing: 0.0625rem;
  text-transform: uppercase;
  color: var(--white);
}

.step-indicator.is-active .step-indicator__number {
  background: var(--blue-300);
  border-color: var(--blue-300);
  color: var(--blue-950);
}

.step-indicator.is-complete .step-indicator__number {
  background: var(--white);
  border-color: var(--white);
  color: var(--blue-950);
}

/* Form panel */
.form-panel {
  display: flex;
  flex-direction: column;
  flex: 1;
  margin-top: -1.0625rem;
  padding: 1.375rem 1.5rem 1.5rem;
  background: var(--white);
  border-radius: 0.625rem;
  box-shadow: 0 1.5625rem 3.125rem -0.75rem rgba(0, 0, 0, 0.25);
}

.form-step {
  flex: 1;
}

.form-step[hidden] {
  display: none;
}

.form-step__title {
  margin: 0 0 0.5rem;
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--blue-950);
  letter-spacing: 0.0125rem;
}

.form-step__description {
  margin: 0 0 2.125rem;
}

/* Fields */
.field + .field {
  margin-top: 1.5rem;
}

.field__label {
  display: block;
  margin-bottom: 0.4375rem;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--blue-950);
}

.field__input {
  width: 100%;
  padding: 0.9375rem 1rem;
  border: 1px solid var(--purple-200);
  border-radius: 0.5rem;
  color: var(--blue-950);
  background: var(--white);
  transition: border-color var(--transition), box-shadow var(--transition);
}

.field__input::placeholder {
  color: var(--grey-500);
  font-weight: 500;
}

.field__input:hover {
  border-color: var(--grey-500);
}

.field__input:focus {
  outline: none;
  border-color: var(--purple-600);
  box-shadow: 0 0 0 1px var(--purple-600);
}

.field__input.is-error {
  border-color: var(--red-500);
}

.field__input.is-error:focus {
  box-shadow: 0 0 0 1px var(--red-500);
}

.field__error {
  min-height: 1.25rem;
  margin: 0.375rem 0 0;
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--red-500);
}

.field__error--center {
  text-align: center;
  margin-top: 1rem;
}

/* Plan cards */
.plan-options {
  display: grid;
  gap: 0.75rem;
  margin-bottom: 2.125rem;
}

.plan-card {
  cursor: pointer;
}

.plan-card__input {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

.plan-card__content {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1.125rem 1rem;
  border: 1px solid var(--purple-200);
  border-radius: 0.5rem;
  transition: border-color var(--transition), background-color var(--transition);
}

.plan-card__input:focus-visible + .plan-card__content {
  outline: 2px solid var(--purple-600);
  outline-offset: 2px;
}

.plan-card__input:checked + .plan-card__content {
  border-color: var(--purple-600);
  background: var(--blue-50);
}

.plan-card__input:not(:checked):hover + .plan-card__content {
  border-color: var(--purple-600);
}

.plan-card__name {
  display: block;
  font-weight: 700;
  color: var(--blue-950);
}

.plan-card__price {
  display: block;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--grey-500);
}

/* Billing toggle */
.billing-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1.5rem;
  padding: 1rem;
  background: var(--blue-100);
  border-radius: 0.5rem;
}

.billing-toggle__label {
  font-weight: 700;
  color: var(--blue-950);
}

.billing-toggle__badge {
  margin-left: 0.5rem;
  padding: 0.125rem 0.5rem;
  border-radius: 0.25rem;
  background: var(--blue-950);
  color: var(--white);
  font-size: 0.875rem;
  font-weight: 700;
}

.toggle {
  position: relative;
  display: inline-flex;
  cursor: pointer;
}

.toggle__input {
  position: absolute;
  opacity: 0;
  width: 0;
  height: 0;
}

.toggle__track {
  width: 2.375rem;
  height: 1.25rem;
  background: var(--blue-950);
  border-radius: 999px;
  position: relative;
  transition: background-color var(--transition);
}

.toggle__track::after {
  content: "";
  position: absolute;
  top: 0.25rem;
  left: 0.25rem;
  width: 0.75rem;
  height: 0.75rem;
  background: var(--white);
  border-radius: 50%;
  transition: transform var(--transition);
}

.toggle__input:checked + .toggle__track::after {
  transform: translateX(1.125rem);
}

.toggle__input:focus-visible + .toggle__track {
  outline: 2px solid var(--purple-600);
  outline-offset: 2px;
}

/* Add-on cards */
.addon-options {
  display: grid;
  gap: 0.75rem;
}

.addon-card {
  cursor: pointer;
}

.addon-card__input {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

.addon-card__content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1.125rem 1rem;
  border: 1px solid var(--purple-200);
  border-radius: 0.5rem;
  transition: border-color var(--transition), background-color var(--transition);
}

.addon-card__input:focus-visible + .addon-card__content {
  outline: 2px solid var(--purple-600);
  outline-offset: 2px;
}

.addon-card__input:checked + .addon-card__content {
  border-color: var(--purple-600);
  background: var(--blue-50);
}

.addon-card__input:not(:checked):hover + .addon-card__content {
  border-color: var(--purple-600);
}

.addon-card__name {
  display: block;
  font-weight: 700;
  color: var(--blue-950);
}

.addon-card__description,
.addon-card__price {
  display: block;
  font-size: 0.875rem;
  font-weight: 500;
}

.addon-card__check {
  width: 1.25rem;
  height: 1.25rem;
  border: 1px solid var(--purple-200);
  border-radius: 0.25rem;
  flex-shrink: 0;
  position: relative;
  transition: border-color var(--transition), background-color var(--transition);
}

.addon-card__input:checked + .addon-card__content .addon-card__check {
  border-color: var(--purple-600);
  background: var(--purple-600);
  background-image: url("./assets/images/icon-checkmark.svg");
  background-repeat: no-repeat;
  background-position: center;
  background-size: 0.6875rem;
}

/* Summary */
.summary {
  padding: 1.25rem 1rem;
  background: var(--blue-50);
  border-radius: 0.5rem;
}

.summary__plan {
  padding-bottom: 1.25rem;
  border-bottom: 1px solid var(--purple-200);
}

.summary__row {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1rem;
}

.summary__name {
  display: block;
  font-weight: 700;
  color: var(--blue-950);
}

.summary__price {
  display: block;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--grey-500);
}

.summary__change {
  padding: 0;
  border: none;
  background: none;
  color: var(--grey-500);
  font-weight: 500;
  text-decoration: underline;
  cursor: pointer;
  transition: color var(--transition);
}

.summary__change:hover,
.summary__change:focus-visible {
  color: var(--purple-600);
  outline: none;
}

.summary__addons {
  list-style: none;
  margin: 0;
  padding: 1.25rem 0;
  border-bottom: 1px solid var(--purple-200);
}

.summary__addons:empty {
  display: none;
}

.summary__addon {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  font-size: 0.875rem;
  font-weight: 500;
}

.summary__addon + .summary__addon {
  margin-top: 0.75rem;
}

.summary__total {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 1.25rem;
  color: var(--blue-950);
}

.summary__total-label {
  font-weight: 400;
}

.summary__total-price {
  font-size: 1.25rem;
  font-weight: 700;
}

/* Thank you */
.form-step--thank-you {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 2.5rem 0 1rem;
}

.thank-you__icon {
  margin-bottom: 1.5rem;
}

.thank-you__title {
  margin: 0 0 1rem;
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--blue-950);
}

.thank-you__message {
  margin: 0;
  line-height: 1.6;
}

/* Footer buttons */
.form-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: auto;
  padding-top: 2rem;
}

.form-footer.is-hidden {
  display: none;
}

.btn {
  border: none;
  border-radius: 0.5rem;
  cursor: pointer;
  font-weight: 700;
  transition: background-color var(--transition), color var(--transition), opacity var(--transition);
}

.btn--primary {
  margin-left: auto;
  padding: 0.875rem 1.4375rem;
  background: var(--blue-950);
  color: var(--white);
}

.btn--primary:hover {
  background: hsl(213, 96%, 25%);
}

.btn--primary:focus-visible {
  outline: 2px solid var(--purple-600);
  outline-offset: 2px;
}

.btn--ghost {
  padding: 0;
  background: none;
  color: var(--grey-500);
}

.btn--ghost:hover {
  color: var(--blue-950);
}

.btn--ghost:focus-visible {
  outline: 2px solid var(--purple-600);
  outline-offset: 2px;
}

.attribution {
  padding: 1rem;
  font-size: 0.6875rem;
  text-align: center;
}

.attribution a {
  color: hsl(228, 45%, 44%);
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
  }
}

/* Desktop */
@media (min-width: 48rem) {
  .layout {
    padding: 2rem;
  }

  .form-shell {
    flex-direction: row;
    min-height: 35.5rem;
    background: var(--white);
    border-radius: 0.9375rem;
    box-shadow: 0 1.5625rem 3.125rem -0.75rem rgba(0, 0, 0, 0.25);
    overflow: hidden;
  }

  .sidebar {
    width: 17.125rem;
    flex-shrink: 0;
    background-image: url("./assets/images/bg-sidebar-desktop.svg");
    padding: 2rem 2rem 2.5rem;
    border-radius: 0;
  }

  .steps {
    flex-direction: column;
    align-items: flex-start;
    justify-content: flex-start;
    gap: 2rem;
    height: 100%;
  }

  .step-indicator__text {
    display: block;
  }

  .form-panel {
    margin-top: 0;
    padding: 2.5rem 2.5rem 2rem;
    width: 100%;
    border-radius: 0;
    box-shadow: none;
  }

  .form-step__title {
    font-size: 2rem;
  }

  .plan-options {
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
  }

  .plan-card__content {
    flex-direction: column;
    align-items: flex-start;
    min-height: 10.625rem;
    padding: 1.125rem 1rem 1.25rem;
  }

  .addon-card__content {
    padding: 1.125rem 1.5rem;
  }

  .form-step--thank-you {
    padding: 4.5rem 0 2rem;
  }
}