:root {
  color-scheme: light;
  --paper: #f5efe3;
  --paper-deep: #ece2d0;
  --ink: #17231f;
  --ink-soft: #52605a;
  --vermilion: #d6573f;
  --vermilion-dark: #a83b2a;
  --sage: #8d9b81;
  --gold: #c99a3d;
  --focus: #31584b;
  --line: rgba(23, 35, 31, 0.16);
  --shadow: 0 28px 70px rgba(59, 48, 31, 0.14);
  --serif: "Iowan Old Style", "Palatino Linotype", "Book Antiqua", Palatino,
    "Yu Mincho", "Hiragino Mincho ProN", serif;
  --sans: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI",
    "Noto Sans", "Noto Sans Vietnamese", sans-serif;
}

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

html {
  min-height: 100%;
  background: var(--paper);
  font-family: var(--sans);
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  min-height: 100svh;
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 13% 14%, rgba(214, 87, 63, 0.09) 0 13rem, transparent 13.1rem),
    linear-gradient(112deg, rgba(255, 255, 255, 0.28), transparent 42%),
    var(--paper);
}

body::before {
  position: fixed;
  inset: 0;
  z-index: -1;
  background-image:
    repeating-linear-gradient(0deg, transparent 0 5px, rgba(70, 55, 32, 0.018) 5px 6px),
    repeating-linear-gradient(90deg, transparent 0 9px, rgba(255, 255, 255, 0.16) 9px 10px);
  content: "";
  pointer-events: none;
}

a {
  color: inherit;
}

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

.page-shell {
  display: grid;
  grid-template-rows: auto 1fr auto;
  min-height: 100vh;
  min-height: 100svh;
  overflow-x: clip;
}

.site-header,
.hero,
.site-footer {
  width: min(100% - 3rem, 1180px);
  margin-inline: auto;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
  min-height: 7.25rem;
  border-bottom: 1px solid var(--line);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.78rem;
  color: var(--ink);
  font-size: 0.86rem;
  font-weight: 800;
  letter-spacing: 0.16em;
  text-decoration: none;
}

.brand__mark {
  display: grid;
  width: 2.55rem;
  height: 2.55rem;
  place-items: center;
  border-radius: 50%;
  color: #fffaf1;
  background: var(--vermilion);
  box-shadow: inset 0 0 0 1px rgba(117, 34, 22, 0.16);
  font-family: var(--serif);
  font-size: 1.2rem;
  font-weight: 700;
  letter-spacing: 0;
}

.language-nav {
  display: flex;
  align-items: center;
  gap: 0.85rem;
}

.language-nav__label {
  color: var(--ink-soft);
  font-size: 0.69rem;
  font-weight: 800;
  letter-spacing: 0.13em;
  text-transform: uppercase;
}

.language-nav__links {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: flex-end;
  gap: 0.18rem;
  padding: 0.25rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(255, 252, 245, 0.58);
}

.language-nav a {
  display: inline-flex;
  min-height: 2.75rem;
  align-items: center;
  padding: 0.45rem 0.78rem;
  border-radius: 999px;
  color: var(--ink-soft);
  font-size: 0.73rem;
  font-weight: 720;
  line-height: 1;
  text-decoration: none;
  transition: color 180ms ease, background-color 180ms ease, box-shadow 180ms ease, transform 180ms ease;
}

.language-nav a:hover {
  color: var(--ink);
  background: rgba(214, 87, 63, 0.09);
}

.language-nav a[aria-current="page"] {
  color: #fffaf2;
  background: var(--ink);
}

.language-nav a[data-recommended="true"]:not([aria-current="page"]) {
  color: var(--ink);
  background: rgba(214, 87, 63, 0.1);
  box-shadow: inset 0 0 0 2px var(--vermilion);
}

.language-nav a:focus-visible,
.brand:focus-visible,
.home-link:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 3px;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.08fr) minmax(22rem, 0.92fr);
  align-items: center;
  gap: clamp(2.5rem, 6vw, 6.5rem);
  padding-block: clamp(3.4rem, 8vh, 7.2rem);
}

.hero__copy {
  position: relative;
  z-index: 2;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.68rem;
  margin: 0 0 1.65rem;
  color: var(--vermilion-dark);
  font-size: 0.71rem;
  font-weight: 850;
  letter-spacing: 0.15em;
  text-transform: uppercase;
}

.eyebrow__dot {
  width: 0.58rem;
  height: 0.58rem;
  border: 2px solid var(--vermilion);
  border-radius: 50%;
  box-shadow: 0 0 0 0.3rem rgba(214, 87, 63, 0.11);
}

.hero h1,
.not-found h1 {
  max-width: 10.5ch;
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(3.45rem, 7.3vw, 7rem);
  font-weight: 500;
  letter-spacing: -0.064em;
  line-height: 0.93;
  text-wrap: balance;
}

body[data-page="gateway"] .hero h1 {
  max-width: 13ch;
  font-size: clamp(3.15rem, 6.25vw, 6.25rem);
  letter-spacing: -0.05em;
  line-height: 0.98;
}

html[lang="vi"] .hero h1 {
  max-width: 12ch;
  font-size: clamp(3.2rem, 6.3vw, 6.2rem);
  letter-spacing: -0.035em;
  line-height: 1.04;
}

html[lang="id"] .hero h1 {
  max-width: 13ch;
  font-size: clamp(3.1rem, 6.1vw, 6rem);
  letter-spacing: -0.045em;
  line-height: 1;
}

html[lang="vi"] .eyebrow,
html[lang="id"] .eyebrow {
  max-width: 32rem;
  font-size: 0.77rem;
  letter-spacing: 0.06em;
  line-height: 1.5;
  text-transform: none;
}

.lede {
  max-width: 39rem;
  margin: 1.75rem 0 0;
  color: var(--ink-soft);
  font-size: clamp(1.02rem, 1.45vw, 1.24rem);
  line-height: 1.72;
  text-wrap: pretty;
}

.launch-note {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.95rem 1rem;
  width: min(100%, 36rem);
  margin-top: 2.25rem;
  padding: 1.1rem 1.15rem;
  border: 1px solid var(--line);
  border-left: 3px solid var(--vermilion);
  border-radius: 0.9rem;
  background: rgba(255, 252, 245, 0.62);
  box-shadow: 0 12px 30px rgba(59, 48, 31, 0.06);
}

.launch-note__mark {
  display: grid;
  width: 2.3rem;
  height: 2.3rem;
  place-items: center;
  border-radius: 0.55rem;
  color: var(--vermilion-dark);
  background: rgba(214, 87, 63, 0.11);
  font-family: var(--serif);
  font-size: 1.15rem;
}

.launch-note__label {
  margin: 0 0 0.28rem;
  color: var(--ink);
  font-size: 0.68rem;
  font-weight: 850;
  letter-spacing: 0.13em;
  text-transform: uppercase;
}

.launch-note__text {
  margin: 0;
  color: var(--ink-soft);
  font-size: 0.92rem;
  line-height: 1.55;
}

.study-visual {
  position: relative;
  min-height: 36rem;
  isolation: isolate;
}

.study-visual__sun {
  position: absolute;
  top: 1.5rem;
  right: -2rem;
  z-index: -2;
  width: clamp(13rem, 23vw, 18rem);
  aspect-ratio: 1;
  border-radius: 50%;
  background: var(--vermilion);
  box-shadow: inset -1rem -0.7rem 0 rgba(139, 44, 30, 0.06);
}

.study-visual__line {
  position: absolute;
  right: -5rem;
  bottom: 2.4rem;
  z-index: -2;
  width: 26rem;
  height: 12rem;
  border: solid var(--ink);
  border-width: 2px 0 0;
  border-radius: 50%;
  opacity: 0.14;
  transform: rotate(-11deg);
}

.flashcard {
  position: absolute;
  display: flex;
  width: clamp(15rem, 25vw, 19rem);
  aspect-ratio: 0.72;
  flex-direction: column;
  justify-content: space-between;
  padding: 1.35rem 1.4rem;
  overflow: hidden;
  border: 1px solid rgba(23, 35, 31, 0.13);
  border-radius: 1.4rem;
  background: #fffaf0;
  box-shadow: var(--shadow);
  transform-origin: 50% 90%;
}

.flashcard__queue {
  top: 0.8rem;
  left: 0;
  z-index: -1;
  justify-content: flex-start;
  gap: 0.72rem;
  border-color: rgba(255, 250, 240, 0.08);
  background: var(--ink);
  box-shadow: 0 25px 60px rgba(23, 35, 31, 0.2);
  opacity: 0.93;
  transform: rotate(-9deg);
  animation: flashcard-float-queue 8s ease-in-out infinite;
}

.flashcard__queue-line {
  display: block;
  width: 54%;
  height: 0.32rem;
  border-radius: 999px;
  background: rgba(255, 250, 240, 0.16);
}

.flashcard__queue-line:nth-child(2) {
  width: 72%;
}

.flashcard__queue-line:nth-child(3) {
  width: 42%;
}

.flashcard__chrome {
  display: flex;
  align-items: center;
  justify-content: space-between;
  color: var(--ink-soft);
  font-size: 0.63rem;
  font-weight: 800;
  letter-spacing: 0.13em;
  text-transform: uppercase;
}

.flashcard__deck {
  font-size: 0.92rem;
  letter-spacing: 0.16em;
}

.flashcard__status {
  display: block;
  width: 0.48rem;
  height: 0.48rem;
  border-radius: 50%;
  background: var(--sage);
  box-shadow: 0 0 0 0.26rem rgba(141, 155, 129, 0.16);
}

.flashcard__front {
  top: 2.4rem;
  left: 3.9rem;
  z-index: 3;
  color: var(--ink);
  transform: rotate(-1.5deg);
  animation: flashcard-float-front 6.5s ease-in-out infinite;
}

.flashcard__prompt {
  position: relative;
  display: grid;
  flex: 1;
  place-items: center;
  isolation: isolate;
}

.flashcard__prompt::before {
  position: absolute;
  z-index: -1;
  width: 8.4rem;
  aspect-ratio: 1;
  border-radius: 50%;
  background: rgba(214, 87, 63, 0.09);
  content: "";
}

.flashcard__glyph {
  color: var(--vermilion-dark);
  font-family: var(--serif);
  font-size: clamp(6.5rem, 10vw, 8.4rem);
  font-weight: 500;
  line-height: 1;
}

.flashcard__reveal {
  display: grid;
  min-height: 3.15rem;
  place-items: center;
  border-top: 1px solid var(--line);
  border-radius: 0 0 0.72rem 0.72rem;
  color: var(--ink-soft);
  background: rgba(236, 226, 208, 0.34);
}

.flashcard__reveal-mark {
  display: block;
  width: 2.4rem;
  height: 0.45rem;
  border: solid currentcolor;
  border-width: 0 0 2px 2px;
  transform: rotate(-45deg) translate(0.25rem, -0.25rem);
}

.flashcard__answer {
  top: 8.2rem;
  right: -0.4rem;
  z-index: 2;
  color: #3c5147;
  background: #e4e8dc;
  transform: rotate(7deg);
  animation: flashcard-float-answer 7.5s ease-in-out infinite;
}

.flashcard__answer-body {
  display: grid;
  flex: 1;
  align-content: center;
  gap: 0.78rem;
  padding-inline: 0.45rem;
}

.flashcard__answer-line {
  display: block;
  width: 100%;
  height: 0.62rem;
  border-radius: 999px;
  background: rgba(60, 81, 71, 0.14);
}

.flashcard__answer-line:nth-child(2) {
  width: 78%;
}

.flashcard__answer-line:nth-child(3) {
  width: 48%;
}

.flashcard__ratings {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.68rem;
  padding-top: 1rem;
  border-top: 1px solid rgba(60, 81, 71, 0.15);
}

.flashcard__rating {
  display: flex;
  min-height: 3rem;
  align-items: center;
  justify-content: center;
  gap: 0.48rem;
  border: 1px solid currentcolor;
  border-radius: 0.78rem;
  font-size: 0.76rem;
  font-weight: 850;
  letter-spacing: 0.06em;
}

.flashcard__rating[data-rating="again"] {
  color: var(--vermilion-dark);
  background: rgba(214, 87, 63, 0.09);
}

.flashcard__rating[data-rating="good"] {
  color: #31584b;
  background: rgba(49, 88, 75, 0.08);
}

.flashcard__rating-icon {
  font-size: 1.05rem;
}

.flashcard__rating-label {
  line-height: 1;
}

.site-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  min-height: 5.4rem;
  border-top: 1px solid var(--line);
  color: var(--ink-soft);
  font-size: 0.78rem;
}

.site-footer p {
  margin: 0;
}

.site-footer__domain {
  color: var(--ink);
  font-weight: 780;
  letter-spacing: 0.05em;
}

.not-found {
  display: grid;
  width: min(100% - 3rem, 48rem);
  margin: auto;
  padding-block: 5rem;
  text-align: center;
}

.not-found .eyebrow {
  justify-self: center;
}

.not-found h1 {
  max-width: none;
  font-size: clamp(3.6rem, 9vw, 7.5rem);
}

.not-found .lede {
  margin-inline: auto;
}

.home-link {
  display: inline-flex;
  min-height: 3rem;
  align-items: center;
  justify-content: center;
  justify-self: center;
  margin-top: 2rem;
  padding: 0.7rem 1.15rem;
  border-radius: 999px;
  color: #fffaf2;
  background: var(--ink);
  font-size: 0.85rem;
  font-weight: 780;
  text-decoration: none;
}

@keyframes flashcard-float-queue {
  0%,
  100% { transform: translateY(0) rotate(-9deg); }
  50% { transform: translateY(-0.35rem) rotate(-7.5deg); }
}

@keyframes flashcard-float-answer {
  0%,
  100% { transform: translateY(0) rotate(7deg); }
  50% { transform: translateY(0.45rem) rotate(5.7deg); }
}

@keyframes flashcard-float-front {
  0%,
  100% { transform: translateY(0) rotate(-1.5deg); }
  50% { transform: translateY(-0.55rem) rotate(-0.2deg); }
}

@media (max-width: 900px) {
  .site-header {
    align-items: flex-start;
    padding-block: 1.3rem;
  }

  .language-nav {
    align-items: flex-end;
    flex-direction: column;
    gap: 0.45rem;
  }

  .hero {
    grid-template-columns: 1fr;
    gap: 2rem;
    padding-top: 3.5rem;
  }

  .hero__copy {
    max-width: 46rem;
  }

  .study-visual {
    width: min(100%, 34rem);
    min-height: 33rem;
    margin-inline: auto;
  }

  .flashcard {
    width: clamp(13.5rem, 42vw, 17rem);
  }
}

@media (max-width: 620px) {
  .site-header,
  .hero,
  .site-footer {
    width: min(100% - 2rem, 1180px);
  }

  .site-header {
    align-items: stretch;
    flex-direction: column;
    gap: 1rem;
  }

  .brand {
    align-self: flex-start;
  }

  .language-nav {
    align-items: stretch;
  }

  .language-nav__links {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
  }

  .language-nav a {
    justify-content: center;
    padding-inline: 0.45rem;
    text-align: center;
  }

  .hero {
    padding-block: 3rem 3.5rem;
  }

  .hero h1,
  body[data-page="gateway"] .hero h1,
  html[lang="vi"] .hero h1,
  html[lang="id"] .hero h1 {
    font-size: clamp(3rem, 16vw, 4.55rem);
    line-height: 0.96;
  }

  .lede {
    margin-top: 1.35rem;
    font-size: 1rem;
  }

  .study-visual {
    min-height: 27.5rem;
  }

  .study-visual__sun {
    right: -3rem;
    width: 13rem;
  }

  .flashcard {
    width: min(13rem, 62vw);
    padding: 1rem;
    border-radius: 1.1rem;
  }

  .flashcard__glyph {
    font-size: 5.5rem;
  }

  .flashcard__queue {
    top: 0.4rem;
    left: 0.3rem;
  }

  .flashcard__front {
    top: 1.5rem;
    left: 1.4rem;
  }

  .flashcard__answer {
    top: 7.4rem;
    right: 0.2rem;
  }

  .flashcard__ratings {
    gap: 0.4rem;
  }

  .flashcard__rating {
    min-height: 2.65rem;
  }

  .site-footer {
    align-items: flex-start;
    flex-direction: column;
    justify-content: center;
    padding-block: 1.35rem;
  }
}

@media (max-width: 400px) {
  .language-nav__links {
    grid-template-columns: 1fr;
  }

  .language-nav a {
    min-height: 2.9rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

@media (prefers-contrast: more) {
  :root {
    --ink-soft: #26332e;
    --line: rgba(23, 35, 31, 0.42);
  }
}

@media (forced-colors: active) {
  .brand__mark,
  .language-nav a[aria-current="page"],
  .language-nav a[data-recommended="true"],
  .home-link {
    border: 1px solid ButtonText;
  }

  .flashcard,
  .launch-note,
  .language-nav__links {
    border: 1px solid CanvasText;
  }
}