:root {
  --brand-color: #467fcf;
  --brand-color-dark: #3568b0;
  --brand-color-deep: #284f89;
  --brand-color-light: #e8eff9;
  --brand-color-bright: #176fba;
  --brand-color-soft: #bad0ef;
  --color-night-ink: #000437;
  --color-paper-white: #ffffff;
  --color-charcoal: #4b4b4b;
  --color-pencil-gray: #777777;
  --color-faded-gray: #afafaf;
  --color-soft-line: #e5e5e5;

  --font-feather: "Arial Rounded MT Bold", "Avenir Next Rounded", ui-rounded, system-ui, sans-serif;
  --font-duolingo-sans: Inter, "Nunito Sans", ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;

  --text-caption: 13px;
  --text-nav-label: 15px;
  --text-body: 17px;
  --text-subheading: 19px;
  --text-heading-sm: 32px;
  --text-heading: 48px;
  --text-display: 64px;

  --spacing-8: 8px;
  --spacing-12: 12px;
  --spacing-16: 16px;
  --spacing-24: 24px;
  --spacing-32: 32px;
  --spacing-40: 40px;
  --spacing-48: 48px;
  --spacing-64: 64px;
  --spacing-80: 80px;
  --spacing-96: 96px;

  --page-max-width: 1200px;
  --radius: 12px;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 94px;
}

body {
  margin: 0;
  color: var(--color-charcoal);
  background: var(--color-paper-white);
  font-family: var(--font-duolingo-sans);
  font-size: var(--text-body);
  font-weight: 500;
  line-height: 1.47;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a {
  color: inherit;
  text-decoration: none;
}

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

button,
a {
  -webkit-tap-highlight-color: transparent;
}

.shell {
  width: min(var(--page-max-width), calc(100% - 48px));
  margin-inline: auto;
}

.skip-link {
  position: fixed;
  z-index: 200;
  top: var(--spacing-12);
  left: var(--spacing-12);
  padding: var(--spacing-12) var(--spacing-16);
  color: var(--color-night-ink);
  background: var(--color-paper-white);
  border: 2px solid var(--color-night-ink);
  border-radius: var(--radius);
  transform: translateY(-180%);
}

.skip-link:focus {
  transform: translateY(0);
}

.landing-notice {
  position: fixed;
  z-index: 300;
  top: 98px;
  left: 50%;
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  width: min(620px, calc(100% - 32px));
  padding: var(--spacing-16);
  color: var(--color-night-ink);
  background: var(--color-paper-white);
  border: 2px solid var(--color-night-ink);
  border-left: 8px solid var(--brand-color);
  border-radius: 16px;
  transform: translateX(-50%);
}

.landing-notice--error {
  background: #fff7f6;
  border-left-color: #b42318;
}

.landing-notice__icon {
  display: grid;
  place-items: center;
  width: 32px;
  height: 32px;
  margin-right: var(--spacing-12);
  color: var(--color-paper-white);
  background: var(--brand-color);
  border-radius: 50%;
  font-weight: 800;
}

.landing-notice--error .landing-notice__icon {
  background: #b42318;
}

.landing-notice__message {
  margin: 0;
  font-size: 16px;
  font-weight: 700;
}

.landing-notice__close {
  display: grid;
  place-items: center;
  width: 36px;
  height: 36px;
  margin-left: var(--spacing-12);
  padding: 0;
  color: var(--color-night-ink);
  background: transparent;
  border: 0;
  border-radius: 50%;
  cursor: pointer;
  font: inherit;
  font-size: 24px;
  line-height: 1;
}

.landing-notice__close:hover,
.landing-notice__close:focus-visible {
  color: var(--brand-color-deep);
  background: var(--brand-color-light);
  outline: 2px solid var(--brand-color);
  outline-offset: 1px;
}

.site-header {
  position: sticky;
  z-index: 100;
  top: 0;
  background: var(--color-paper-white);
  border-bottom: 2px solid var(--color-soft-line);
}

.nav-shell {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 82px;
  gap: var(--spacing-24);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-12);
  color: var(--color-charcoal);
  font-size: 23px;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.brand img {
  width: 44px;
  height: 44px;
}

.brand-dot {
  color: var(--brand-color);
}

.nav-links,
.nav-actions {
  display: flex;
  align-items: center;
}

.nav-links {
  gap: var(--spacing-32);
  margin-left: auto;
  margin-right: var(--spacing-16);
}

.nav-link,
.account-link {
  font-size: var(--text-nav-label);
  font-weight: 700;
  letter-spacing: 0.053em;
  text-transform: uppercase;
}

.nav-link {
  color: var(--color-pencil-gray);
}

.nav-link:hover,
.nav-link:focus-visible,
.account-link:hover,
.account-link:focus-visible,
.text-link:hover,
.text-link:focus-visible {
  color: var(--brand-color-bright);
}

.nav-actions {
  gap: var(--spacing-16);
}

.account-link {
  color: var(--brand-color-bright);
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-8);
  min-height: 50px;
  padding: var(--spacing-12) var(--spacing-24);
  border-radius: var(--radius);
  font-size: var(--text-nav-label);
  font-weight: 700;
  letter-spacing: 0.053em;
  line-height: 1.2;
  text-align: center;
  text-transform: uppercase;
  transition: background-color 120ms ease, color 120ms ease, border-color 120ms ease, transform 120ms ease;
}

.button:hover {
  transform: translateY(-1px);
}

.button:active {
  transform: translateY(1px);
}

.button--primary {
  color: var(--color-paper-white);
  background: var(--brand-color-dark);
  border: 2px solid var(--brand-color-dark);
}

.button--primary:hover,
.button--primary:focus-visible {
  color: var(--color-paper-white);
  background: var(--brand-color-deep);
  border-color: var(--brand-color-deep);
}

.button--outline {
  color: var(--brand-color-bright);
  background: transparent;
  border: 2px solid var(--color-faded-gray);
}

.button--outline:hover,
.button--outline:focus-visible {
  color: var(--brand-color-bright);
  border-color: var(--brand-color-bright);
}

.button--small {
  min-height: 44px;
  padding: 10px var(--spacing-16);
}

.button:focus-visible,
.brand:focus-visible,
.nav-link:focus-visible,
.account-link:focus-visible,
.text-link:focus-visible,
.footer-link:focus-visible {
  outline: 3px solid var(--brand-color-bright);
  outline-offset: 3px;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 0.82fr) minmax(480px, 1.18fr);
  align-items: center;
  gap: clamp(40px, 7vw, 96px);
  min-height: 730px;
  padding-block: var(--spacing-80);
}

.hero-copy {
  max-width: 510px;
}

.kicker {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-8);
  margin: 0 0 var(--spacing-24);
  padding: var(--spacing-8) var(--spacing-12);
  color: var(--color-charcoal);
  background: var(--brand-color-light);
  border-radius: var(--radius);
  font-size: var(--text-caption);
  font-weight: 700;
  letter-spacing: 0.053em;
  line-height: 1.23;
  text-transform: uppercase;
}

.kicker-mark {
  width: 10px;
  height: 10px;
  background: var(--brand-color);
  border: 2px solid var(--color-charcoal);
  border-radius: 50%;
}

.hero h1 {
  margin: 0;
  color: var(--color-charcoal);
  font-family: var(--font-feather);
  font-size: clamp(40px, 4.7vw, 58px);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.14;
}

.hero-copy > p:not(.kicker) {
  max-width: 480px;
  margin: var(--spacing-24) 0 0;
  color: var(--color-pencil-gray);
  font-size: var(--text-body);
}

.hero-actions {
  display: grid;
  gap: var(--spacing-12);
  width: min(100%, 370px);
  margin-top: var(--spacing-32);
}

.hero-small-print {
  margin-top: var(--spacing-16) !important;
  color: var(--color-faded-gray) !important;
  font-size: var(--text-caption) !important;
  text-align: center;
}

.hero-illustration {
  margin: 0;
}

.hero-illustration img {
  width: 100%;
  max-height: 540px;
  object-fit: contain;
}

.chapter-nav {
  background: var(--color-paper-white);
  border-block: 2px solid var(--color-soft-line);
}

.chapter-links {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: clamp(24px, 7vw, 88px);
  min-height: 76px;
}

.chapter-links a {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-8);
  color: var(--color-pencil-gray);
  font-size: var(--text-nav-label);
  font-weight: 700;
  letter-spacing: 0.053em;
  text-transform: uppercase;
}

.chapter-links a:hover,
.chapter-links a:focus-visible {
  color: var(--brand-color-bright);
}

.chapter-number {
  color: var(--brand-color);
  font-size: var(--text-caption);
}

.story-section {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  align-items: center;
  gap: clamp(56px, 9vw, 120px);
  min-height: 760px;
  padding-block: var(--spacing-96);
  border-bottom: 2px solid var(--color-soft-line);
}

.story-section--reverse .story-copy {
  order: 2;
}

.story-section--reverse .story-illustration {
  order: 1;
}

.story-copy {
  max-width: 510px;
}

.section-label {
  display: inline-block;
  margin: 0 0 var(--spacing-16);
  color: var(--brand-color-bright);
  font-size: var(--text-caption);
  font-weight: 700;
  letter-spacing: 0.053em;
  text-transform: uppercase;
}

.story-copy h2,
.closing-copy h2 {
  margin: 0;
  color: var(--brand-color);
  font-family: var(--font-feather);
  font-size: clamp(var(--text-heading), 5vw, var(--text-display));
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

.story-copy > p:not(.section-label),
.closing-copy > p {
  max-width: 480px;
  margin: var(--spacing-24) 0 0;
  color: var(--color-pencil-gray);
  font-size: var(--text-body);
}

.feature-list {
  display: grid;
  gap: var(--spacing-16);
  margin: var(--spacing-32) 0;
  padding: 0;
  list-style: none;
}

.feature-list li {
  display: flex;
  align-items: flex-start;
  gap: var(--spacing-12);
  color: var(--color-charcoal);
  font-size: var(--text-subheading);
  font-weight: 700;
  line-height: 1.4;
}

.feature-list-icon {
  flex: 0 0 auto;
  display: grid;
  place-items: center;
  width: 30px;
  height: 30px;
  color: var(--color-paper-white);
  background: var(--brand-color);
  border: 2px solid var(--color-charcoal);
  border-radius: 50%;
  font-size: 15px;
  line-height: 1;
}

.text-link {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-8);
  color: var(--brand-color-bright);
  font-size: var(--text-nav-label);
  font-weight: 700;
  letter-spacing: 0.053em;
  text-transform: uppercase;
}

.text-link svg {
  width: 19px;
  height: 19px;
  fill: none;
  stroke: currentColor;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-width: 2.5;
}

.story-illustration {
  margin: 0;
}

.story-illustration img {
  width: 100%;
  max-height: 530px;
  object-fit: contain;
}

.closing-section {
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: center;
  gap: var(--spacing-64);
  min-height: 410px;
  padding-block: var(--spacing-80);
}

.closing-copy h2 {
  font-size: clamp(42px, 5vw, 58px);
}

.closing-actions {
  display: grid;
  gap: var(--spacing-12);
  width: 350px;
}

.site-footer {
  padding-block: var(--spacing-64) var(--spacing-40);
  color: var(--color-paper-white);
  background: var(--brand-color-dark);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1fr;
  gap: var(--spacing-48);
}

.brand--footer {
  color: var(--color-paper-white);
}

.brand--footer img {
  background: var(--color-paper-white);
  border-radius: var(--radius);
}

.footer-tagline {
  max-width: 290px;
  margin: var(--spacing-16) 0 0;
  color: var(--brand-color-light);
  font-size: 15px;
}

.footer-column h3 {
  margin: 0 0 var(--spacing-16);
  color: var(--color-paper-white);
  font-size: var(--text-nav-label);
  font-weight: 700;
  letter-spacing: 0.053em;
  text-transform: uppercase;
}

.footer-column ul {
  display: grid;
  gap: var(--spacing-8);
  margin: 0;
  padding: 0;
  list-style: none;
}

.footer-link {
  color: var(--brand-color-light);
  font-size: 15px;
  font-weight: 700;
}

.footer-link:hover,
.footer-link:focus-visible {
  color: var(--color-paper-white);
}

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--spacing-24);
  margin-top: var(--spacing-48);
  padding-top: var(--spacing-24);
  border-top: 2px solid rgba(255, 255, 255, 0.35);
  color: var(--brand-color-light);
  font-size: var(--text-caption);
}

@media (max-width: 980px) {
  .nav-links {
    display: none;
  }

  .hero {
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-40);
  }

  .story-section {
    gap: var(--spacing-48);
  }

  .footer-grid {
    grid-template-columns: 1.4fr repeat(3, 0.8fr);
    gap: var(--spacing-32);
  }
}

@media (max-width: 760px) {
  html {
    scroll-padding-top: 74px;
  }

  .shell {
    width: min(100% - 32px, var(--page-max-width));
  }

  .nav-shell {
    min-height: 72px;
  }

  .landing-notice {
    top: 84px;
  }

  .brand {
    font-size: 20px;
  }

  .brand img {
    width: 38px;
    height: 38px;
  }

  .account-link {
    display: none;
  }

  .button--small {
    min-height: 42px;
    padding-inline: var(--spacing-12);
    font-size: 13px;
  }

  .hero {
    grid-template-columns: 1fr;
    min-height: 0;
    padding-block: var(--spacing-64);
  }

  .hero-copy {
    max-width: none;
  }

  .hero h1 {
    max-width: 580px;
  }

  .hero-illustration {
    margin-top: var(--spacing-24);
  }

  .hero-illustration img {
    max-height: 460px;
  }

  .chapter-links {
    justify-content: flex-start;
    overflow-x: auto;
    padding-inline: var(--spacing-16);
  }

  .chapter-links a {
    flex: 0 0 auto;
  }

  .story-section,
  .story-section--reverse {
    grid-template-columns: 1fr;
    gap: var(--spacing-48);
    min-height: 0;
    padding-block: var(--spacing-80);
  }

  .story-section .story-copy,
  .story-section--reverse .story-copy {
    order: 1;
    max-width: none;
  }

  .story-section .story-illustration,
  .story-section--reverse .story-illustration {
    order: 2;
  }

  .story-illustration img {
    max-height: 460px;
  }

  .closing-section {
    grid-template-columns: 1fr;
    gap: var(--spacing-40);
    padding-block: var(--spacing-64);
  }

  .closing-actions {
    width: min(100%, 390px);
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }

  .footer-brand {
    grid-column: 1 / -1;
  }
}

@media (max-width: 480px) {
  .nav-actions .button {
    min-width: 0;
  }

  .hero h1 {
    font-size: 38px;
  }

  .hero-actions {
    width: 100%;
  }

  .story-copy h2,
  .closing-copy h2 {
    font-size: 44px;
  }

  .feature-list li {
    font-size: 17px;
  }

  .footer-grid {
    grid-template-columns: 1fr;
  }

  .footer-brand {
    grid-column: auto;
  }

  .footer-bottom {
    align-items: flex-start;
    flex-direction: column;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
  }
}

@media print {
  .landing-notice,
  .site-header,
  .chapter-nav,
  .hero-actions,
  .closing-actions,
  .site-footer {
    display: none !important;
  }

  .hero,
  .story-section,
  .closing-section {
    min-height: 0;
    padding-block: 32px;
  }
}