/* fonts */

@font-face {
  font-family: "Inter";
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: url(../assets/fonts/static/Inter-Regular.ttf) format("truetype");
}

@font-face {
  font-family: "Inter";
  font-style: normal;
  font-weight: 600;
  font-display: swap;
  src: url(../assets/fonts/static/Inter-SemiBold.ttf) format("truetype");
}

/* vars */

:root {
  --primary: #345ff6;
  --secondary: #253347;
  --neutral: #5e6e85;
  --white: #ffffff;
}

/* globals */

html {
  box-sizing: border-box;
}

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

html {
  font: 400 16px/24px "Inter";
}

body {
  margin: 0;
  background: var(--white);
  color: var(--secondary);
}

h1,
h2,
h3,
h4,
h5,
h6,
p {
  margin-block: 0;
}

b {
  font-weight: 600;
}

button {
  appearance: none;
  border: none;
  background: none;
  color: inherit;
  font: inherit;
  cursor: pointer;
}

input {
  appearance: none;
  font: inherit;
  cursor: pointer;
}

button:focus {
  outline: none;
}

ul {
  margin-block: 0;
  padding-inline-start: 0;
  list-style: none;
}

img {
  display: block;
}

/* texts */

.heading-xl,
.heading-l,
.heading-m,
.heading-s {
  font-weight: 600;
  line-height: 1.1;
  letter-spacing: -0.05em;
}

.heading-xl {
  font-size: 3rem;
}

.heading-l {
  font-size: 2rem;
}

.heading-m {
  font-size: 1.5rem;
}

.heading-s {
  font-size: 1.25rem;
}

.body-m,
.body-m-bold,
.body-s {
  line-height: 1.5;
  letter-spacing: normal;
}

.body-m {
  font-size: 1rem;
}

.body-m-bold {
  font-size: 1rem;
  font-weight: 600;
}

.body-s {
  font-size: 0.875rem;
}

.bold {
  font-weight: 600;
}

.muted {
  color: var(--neutral);
}

/* controls */

.field {
  position: relative;
  display: inline-block;
  width: 100%;
}

.field input,
.field span {
  /* NOTE: same as .heading-m */
  font-size: 1.5rem;
  font-weight: 600;
  line-height: 1.1;
}

.field input {
  width: 100%;
  padding: 1.25rem 4.5rem 1.25rem 1.5rem;
  border: 1px solid var(--neutral);
  border-radius: 0.75rem;
}

.field input:hover,
.field input:active {
  border-color: var(--primary);
}

.field input:focus {
  outline: var(--primary) solid 2px;
  outline-offset: -2px;
}

.field input::placeholder {
  color: var(--neutral);
}

.field span {
  position: absolute;
  top: 50%;
  right: 1.5rem;
  transform: translateY(-50%);
  color: var(--primary);
}

.fieldset {
  margin: 0;
  border: none;
  padding: 0;
  width: 100%;
}

.fieldset legend {
  margin-bottom: 0.5rem;
  color: var(--neutral);
}

/* other components */

.tab {
  position: relative;
  display: flex;
  align-items: center;
  gap: 1.125rem;
  font-weight: 600;
}

.tab::before {
  content: "";
  width: 1.8125em;
  height: 1.8125em;
  border: 1px solid var(--neutral);
  border-radius: 50%;
}

.tab::after {
  content: "";
  position: absolute;
  top: calc(1.9375em / 2 - 0.4375em);
  left: calc(1.9375em / 2 - 0.1875em);
  width: 0.9375em;
  height: 0.9375em;
  border-radius: 50%;
  background: var(--primary);
  transition:
    transform 0.25s ease-out,
    opacity 0.25s ease-out;
}

.tab[data-selected]::before {
  border-color: transparent;
  background-color: hsla(227, 92%, 58%, 0.15);
}

.tab:not([data-selected])::after {
  opacity: 0;
  transform: scale(0.5);
}

.tab:hover::before {
  border-color: var(--primary);
}

.tab:focus::before {
  outline: var(--primary) solid 2px;
  outline-offset: -2px;
}

.tab-pane:not(.active) {
  display: none;
}

/* utils */

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

/* content */

body {
  padding: 2rem 1.5rem 6rem;
}

.logo {
  width: 2.5rem;
  height: 2.5rem;
  margin: 0 auto 1.5rem;
}

.content {
  display: grid;
}

.lead::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 640px;
  border-bottom-left-radius: 35px;
  border-bottom-right-radius: 35px;
  background: linear-gradient(-45deg, #d6e6fe, #d7fcfe00);
  z-index: -1;
}

.lead h1 {
  margin-bottom: 1.5rem;
  text-align: center;
}

.lead p {
  color: var(--neutral);
  text-align: center;
}

.calculator {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  border-radius: 1rem;
  margin-top: 3rem;
  padding: 1.5rem;
  background: var(--white);
  box-shadow: 1rem 2rem 3.5rem #90afd040;
}

.calculator__unit {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.calculator__unit li {
  width: 100%;
}

.calculator__params {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

#imperial .fieldset {
  display: grid;
  grid-template-columns: 1fr 1fr;
  column-gap: 1rem;
}

.calculator__result {
  overflow: hidden;
  border-radius: 1rem;
}

#bmi {
  padding: 2rem;
  color: var(--white);
  background: var(--primary);
}

#bmi.welcome h3 {
  margin-bottom: 1rem;
}

#bmi:not(.welcome) h3 {
  display: flex;
  flex-direction: column;
  margin-bottom: 1.5rem;
}

#bmi:not(.welcome) h3 span {
  margin-bottom: 0.5rem;
}

.explanation {
  margin-top: 4.5rem;
}

.explanation__header {
  display: flex;
  flex-direction: column;
  gap: 3rem;
  margin: 0 -1.5rem;
}

.explanation__banner {
  max-width: 100%;
  max-height: 100%;
}

.explanation__meaning {
  padding: 0 1.5rem;
}

.explanation__meaning h2 {
  margin-bottom: 2rem;
}

.explanation__meaning p {
  color: var(--neutral);
}

.explanation__items {
  display: flex;
  flex-direction: column;
  gap: 2.5rem;
  margin-top: 8rem;
}

.explanation__item {
  display: grid;
  align-items: center;
}

.explanation__item::before {
  content: "";
  margin-bottom: 2rem;
  width: 4rem;
  height: 4rem;
  background: var(--icon);
}

.explanation__item h3 {
  margin-bottom: 1.5rem;
}

.explanation__item p {
  color: var(--neutral);
}

.limits {
  margin-top: 8rem;
}

.limits__header {
  text-align: center;
}

.limits__header h3 {
  margin-bottom: 2rem;
}

.limits__header p {
  color: var(--neutral);
}

.limits__items {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-top: 3.5rem;
}

.limits__item {
  border-radius: 1rem;
  padding: 1.5rem;
  max-width: 365px;
  background: var(--white);
  box-shadow: 1rem 2rem 3.5rem #90afd040;
}

.limits__item h4 {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1rem;
}

.limits__item h4::before {
  content: "";
  width: 2rem;
  height: 2rem;
  background: var(--icon);
}

.limits__item p {
  color: var(--neutral);
}

@media (min-width: 768px) {
  body {
    padding: 2rem 2.5rem 6rem;
  }

  .logo {
    margin-bottom: 2.5rem;
  }

  .lead h1 {
    padding: 0 25%;
  }

  .calculator {
    gap: 2rem;
    margin-top: 2.5rem;
    padding: 2rem;
  }

  .calculator__params {
    gap: 1.5rem;
  }

  #metric {
    flex-direction: row;
  }

  #bmi {
    border-top-right-radius: 999rem;
    border-bottom-right-radius: 999rem;
  }

  #bmi:not(.welcome) {
    display: grid;
    align-items: center;
    gap: 1.5rem;
    grid-template-columns: 1fr 1fr;
  }

  #bmi:not(.welcome) h3 {
    margin-bottom: 0;
  }

  .explanation {
    margin-top: 6rem;
  }

  .explanation__header {
    flex-direction: row;
    justify-content: end;
    align-items: center;
    gap: 75px;
    margin: 0;
  }

  .explanation__banner {
    width: auto;
    max-height: 411px;
  }

  .explanation__meaning {
    padding: 0;
    min-width: 331px;
  }

  .explanation__header > * {
    width: 100%;
  }

  .explanation__items {
    margin-top: 9.75rem;
  }

  .explanation__item {
    grid-template-columns: auto 1fr;
  }

  .explanation__item::before {
    grid-row: 1 / span 2;
    margin-right: 2.5rem;
    margin-bottom: 0;
  }

  .limits {
    margin-top: 9.75rem;
  }

  .limits__items {
    justify-content: center;
    gap: 1.5rem 1rem;
  }

  .limits__item {
    flex-basis: calc(50% - 0.5rem);
    padding: 2rem;
  }
}

@media (min-width: 1440px) {
  .heading-xl {
    font-size: 4rem;
  }

  .heading-l {
    font-size: 3rem;
  }

  body {
    padding: 4.625rem 8.75rem 7.5rem;
  }

  .logo {
    width: inherit;
    height: inherit;
    margin: 0 0 1.75rem;
  }

  .content {
    grid-template-columns: 1fr 1fr;
    column-gap: 2rem;
  }

  .content > * {
    flex-basis: calc(50% - 1rem);
  }

  .lead {
    padding-right: 6.125rem;
  }

  .lead::before {
    left: 1.5rem;
    right: unset;
    width: 978px;
    height: 738px;
  }

  .lead h1,
  .lead p {
    text-align: start;
  }

  .lead h1 {
    padding: 0;
    margin: 6.125rem 0 2.125rem;
  }

  .calculator {
    margin-top: 0;
  }

  .explanation {
    grid-column: span 2;
    margin-top: 9.375rem;
  }

  .explanation__header {
    position: relative;
    align-items: end;
    gap: 8.25rem;
  }

  .explanation__header::before {
    content: "";
    position: absolute;
    top: -51px;
    right: 27px;
    width: 85.831px;
    height: 200.501px;
    background: url("../assets/images/pattern-curved-line-left.svg");
  }

  .explanation__banner {
    max-height: 533px;
  }

  .explanation__meaning {
    margin-bottom: 2.5rem;
  }

  .explanation__meaning h2 {
    margin-bottom: 2.125rem;
  }

  .explanation__items {
    flex-direction: row;
    gap: 2rem;
    margin-top: 10.5rem;
  }

  .explanation__item {
    flex: 1;
    grid-template-columns: unset;
  }

  .explanation__item::before {
    grid-row: unset;
    margin-right: 0;
    margin-bottom: 2.75rem;
  }

  .limits {
    position: relative;
    grid-column: span 2;
    margin-top: 13.5rem;
  }

  .limits__header {
    position: absolute;
    text-align: start;
    max-width: 35.25rem;
  }

  .limits__header p::before {
    content: "";
    position: absolute;
    top: calc(100% + 67px);
    left: 165px;
    width: 94.664px;
    height: 122.518px;
    background: url("../assets/images/pattern-curved-line-right.svg");
  }

  .limits__items {
    display: grid;
    grid-template-columns: 1fr auto auto;
    justify-items: end;
    gap: 1.5rem 2rem;
    margin-top: 0;
  }

  .limits__item:nth-child(1) {
    grid-column: span 3;
    margin-right: 6.25rem;
  }

  .limits__item:nth-child(2) {
    grid-column: span 2;
  }

  .limits__item:nth-child(5) {
    grid-column: span 2;
    margin-right: 12.5rem;
  }
}