@font-face {
  font-family: "Open Sans";
  src: url("../fonts/open-sans-v34-vietnamese_latin-ext_latin_hebrew_greek-ext_greek_cyrillic-ext_cyrillic-regular.woff2") format("woff2");
  font-style: normal;
  font-weight: 400;
  font-display: swap;
}

@font-face {
  font-family: "Open Sans";
  src: url("../fonts/open-sans-v34-vietnamese_latin-ext_latin_hebrew_greek-ext_greek_cyrillic-ext_cyrillic-700.woff2") format("woff2");
  font-style: normal;
  font-weight: 700;
  font-display: swap;
}

:root {
  color-scheme: light;
  --page: #f6f7fa;
  --surface: #ffffff;
  --surface-soft: #edf1f7;
  --ink: #142033;
  --muted: #5f6d80;
  --line: #d9e0ea;
  --cobalt: #2859d4;
  --cobalt-deep: #173a9a;
  --cobalt-soft: #dfe8ff;
  --on-cobalt: #ffffff;
  --display: Georgia, "Times New Roman", serif;
  --sans: "Open Sans", "Avenir Next", "Segoe UI", sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  background: var(--page);
}

body {
  min-width: 320px;
  margin: 0;
  background: var(--page);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.55;
  text-rendering: optimizeLegibility;
}

a {
  color: inherit;
}

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

:focus-visible {
  outline: 3px solid var(--cobalt);
  outline-offset: 4px;
}

.skip-link {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 20;
  padding: 9px 14px;
  border-radius: 999px;
  background: var(--surface);
  font-weight: 700;
  text-decoration: none;
  transform: translateY(-170%);
  transition: transform 180ms ease;
}

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

.site-header,
main,
footer {
  width: min(1080px, calc(100% - 48px));
  margin-inline: auto;
}

.site-header {
  display: flex;
  min-height: 82px;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--line);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 0.94rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  text-decoration: none;
}

.brand-mark {
  display: grid;
  width: 32px;
  height: 32px;
  place-items: center;
  border-radius: 10px;
  background: var(--cobalt);
  color: var(--on-cobalt);
  font-size: 0.86rem;
}

.domain {
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.08em;
}

.hero {
  display: grid;
  min-height: 680px;
  grid-template-columns: minmax(0, 1.08fr) minmax(320px, 0.82fr);
  align-items: center;
  gap: clamp(48px, 9vw, 112px);
  padding-block: clamp(68px, 9vw, 112px);
}

.hero-copy {
  max-width: 620px;
}

.eyebrow,
.section-label {
  margin: 0 0 18px;
  color: var(--cobalt);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.22em;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1,
h2 {
  font-family: var(--display);
  font-weight: 700;
  letter-spacing: -0.055em;
}

h1 {
  max-width: 620px;
  margin-bottom: 24px;
  font-size: clamp(4.8rem, 10vw, 8.3rem);
  line-height: 0.78;
}

h2 {
  margin-bottom: 14px;
  font-size: clamp(2.6rem, 6vw, 4.6rem);
  line-height: 0.96;
}

h3 {
  margin-bottom: 5px;
  font-size: clamp(1.25rem, 2.2vw, 1.6rem);
  letter-spacing: -0.035em;
}

.hero-text {
  max-width: 570px;
  margin-bottom: 28px;
  color: var(--muted);
  font-size: clamp(1.05rem, 2vw, 1.26rem);
  line-height: 1.6;
}

.portrait-frame {
  overflow: hidden;
  aspect-ratio: 0.78;
  border-radius: 48% 48% 16px 16px;
  background: var(--cobalt-soft);
  box-shadow: 0 28px 72px rgb(20 32 51 / 0.12);
}

.portrait-frame img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.social-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.social-links a,
.store-links a {
  display: inline-flex;
  min-height: 46px;
  align-items: center;
  justify-content: center;
  gap: 9px;
  border-radius: 999px;
  font-size: 0.84rem;
  font-weight: 700;
  text-decoration: none;
  transition: transform 180ms ease, background-color 180ms ease, border-color 180ms ease;
}

.social-links a {
  padding: 10px 17px;
  border: 1px solid var(--line);
  background: var(--surface);
}

.social-links img {
  width: 18px;
  height: 18px;
}

.social-links a:hover,
.store-links a:hover,
.resource-list a:hover {
  transform: translateY(-2px);
  border-color: var(--cobalt);
}

.resources,
.books {
  padding-block: clamp(84px, 11vw, 136px);
  border-top: 1px solid var(--line);
}

.resources {
  padding-bottom: clamp(76px, 9vw, 112px);
}

.section-heading {
  max-width: 620px;
  margin-bottom: 44px;
}

.section-heading > p:last-child {
  color: var(--muted);
}

.resource-list {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
}

.resource-list a {
  display: grid;
  min-height: 190px;
  grid-template-columns: auto 1fr auto;
  align-content: space-between;
  gap: 18px;
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: 20px;
  background: var(--surface);
  text-decoration: none;
  transition: transform 180ms ease, border-color 180ms ease, box-shadow 180ms ease;
}

.resource-list a:hover {
  box-shadow: 0 18px 42px rgb(20 32 51 / 0.09);
}

.resource-index {
  color: var(--cobalt);
  font-family: var(--display);
  font-size: 1rem;
}

.resource-copy {
  display: flex;
  min-width: 0;
  align-self: end;
  flex-direction: column;
  gap: 5px;
}

.resource-copy strong {
  font-family: var(--display);
  font-size: clamp(1.25rem, 2vw, 1.6rem);
  line-height: 1.08;
}

.resource-copy small {
  color: var(--muted);
  font-size: 0.78rem;
}

.resource-arrow {
  color: var(--cobalt);
  font-size: 1.1rem;
}

.book-row {
  display: grid;
  grid-template-columns: 64px minmax(220px, 1fr) auto;
  align-items: center;
  gap: 28px;
  padding-block: 30px;
  border-top: 1px solid var(--line);
}

.book-row:last-child {
  border-bottom: 1px solid var(--line);
}

.book-number {
  color: var(--cobalt);
  font-family: var(--display);
  font-size: 1.4rem;
}

.book-copy p {
  margin-bottom: 0;
  color: var(--muted);
  font-size: 0.92rem;
}

.store-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 8px;
}

.store-links a {
  min-height: 40px;
  padding: 8px 14px;
  border: 1px solid var(--line);
  background: var(--surface);
}

footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding-block: 30px 48px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.76rem;
}

footer p {
  margin: 0;
}

@media (max-width: 980px) {
  .resource-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 760px) {
  .site-header,
  main,
  footer {
    width: min(100% - 32px, 620px);
  }

  .site-header {
    min-height: 72px;
  }

  .domain {
    display: none;
  }

  .hero {
    min-height: auto;
    grid-template-columns: 1fr;
    gap: 42px;
    padding-block: 58px 72px;
  }

  h1 {
    font-size: clamp(4.2rem, 24vw, 6.5rem);
  }

  .portrait-frame {
    width: min(86vw, 420px);
    justify-self: center;
  }

  .book-row {
    grid-template-columns: 44px 1fr;
    gap: 18px;
  }

  .resource-list {
    grid-template-columns: 1fr;
  }

  .resource-list a {
    min-height: 132px;
  }

  .store-links {
    grid-column: 1 / -1;
    justify-content: stretch;
  }

  .store-links a {
    flex: 1 1 92px;
  }

  footer {
    align-items: flex-start;
    flex-direction: column;
    gap: 4px;
  }
}

@media (prefers-color-scheme: dark) {
  :root {
    color-scheme: dark;
    --page: #101722;
    --surface: #172231;
    --surface-soft: #1e2d40;
    --ink: #f0f4fa;
    --muted: #b1bfd0;
    --line: #2c3c51;
    --cobalt: #5e83ed;
    --cobalt-deep: #bed0ff;
    --cobalt-soft: #dfe8ff;
  }

  .social-links img {
    filter: invert(1);
  }
}

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

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