:root {
  --paper: #f4f7f8;
  --paper-deep: #e4ebef;
  --ink: #101319;
  --muted: #55616c;
  --line: #cbd6dc;
  --accent: #007f7a;
  --accent-dark: #00524f;
  --signal: #2259b8;
  --signal-soft: #dce7fb;
  --edge: #96a8b2;
  --white: #ffffff;
  --max: 1120px;
  color-scheme: light;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background:
    linear-gradient(rgba(16, 19, 25, 0.025) 1px, transparent 1px),
    linear-gradient(90deg, rgba(16, 19, 25, 0.025) 1px, transparent 1px),
    var(--paper);
  background-size: 32px 32px;
  color: var(--ink);
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 18px;
  line-height: 1.65;
}

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

a {
  color: var(--accent);
  text-decoration-thickness: 0.08em;
  text-underline-offset: 0.18em;
}

a:hover {
  color: var(--accent-dark);
}

h1,
h2,
h3 {
  margin: 0 0 0.55em;
  font-family: Georgia, "Times New Roman", serif;
  line-height: 1.05;
  letter-spacing: 0;
}

h1 {
  font-size: clamp(2.8rem, 6vw, 5.9rem);
}

h2 {
  font-size: clamp(1.55rem, 2.4vw, 2.45rem);
}

h3 {
  font-size: 1.35rem;
}

p {
  margin: 0 0 1rem;
}

.container {
  width: min(var(--max), calc(100% - 2rem));
  margin: 0 auto;
}

.skip-link {
  position: absolute;
  left: 1rem;
  top: 1rem;
  z-index: 10;
  transform: translateY(-150%);
  background: var(--ink);
  color: var(--white);
  padding: 0.5rem 0.75rem;
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 5;
  border-bottom: 1px solid var(--line);
  background: rgba(244, 247, 248, 0.92);
  backdrop-filter: blur(12px);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  min-height: 88px;
  padding: 0.75rem 0;
}

.brand img {
  width: 190px;
  aspect-ratio: 724 / 543;
  object-fit: contain;
  object-position: left center;
}

.site-nav,
.footer-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem 1rem;
  align-items: center;
}

.site-nav a,
.footer-nav a {
  color: var(--ink);
  font-size: 0.88rem;
  font-weight: 750;
  letter-spacing: 0.01em;
  text-decoration: none;
}

.site-nav a {
  border: 1px solid transparent;
  padding: 0.32rem 0.48rem;
}

.site-nav a:hover,
.footer-nav a:hover {
  color: var(--accent);
}

.site-nav a:hover {
  border-color: var(--line);
  background: rgba(255, 255, 255, 0.72);
}

.hero {
  position: relative;
  overflow: hidden;
  border-bottom: 1px solid var(--line);
  background:
    linear-gradient(90deg, rgba(244, 247, 248, 0.98), rgba(244, 247, 248, 0.84)),
    linear-gradient(135deg, rgba(34, 89, 184, 0.13), transparent 34%),
    linear-gradient(0deg, rgba(0, 127, 122, 0.08), transparent 58%);
}

.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    linear-gradient(90deg, transparent 0, transparent calc(50% - 1px), rgba(16, 19, 25, 0.08) 50%, transparent calc(50% + 1px)),
    repeating-linear-gradient(90deg, transparent 0 78px, rgba(16, 19, 25, 0.045) 78px 79px);
  pointer-events: none;
}

.hero-inner {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1.12fr) minmax(280px, 0.88fr);
  gap: clamp(2.5rem, 8vw, 6rem);
  align-items: center;
  min-height: 76vh;
  padding: clamp(4rem, 8vw, 7rem) 0;
}

.hero h1 {
  max-width: 10.5ch;
  margin-bottom: 0.28em;
  text-wrap: balance;
}

.eyebrow {
  margin-bottom: 0.75rem;
  color: var(--signal);
  font-size: 0.82rem;
  font-weight: 800;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.lede {
  max-width: 46rem;
  color: var(--muted);
  font-size: clamp(1.15rem, 2vw, 1.35rem);
}

.hero-plate {
  border: 1px solid var(--edge);
  border-top: 5px solid var(--ink);
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.86), rgba(255, 255, 255, 0.68)),
    linear-gradient(135deg, transparent 0 68%, rgba(34, 89, 184, 0.12) 68% 100%);
  box-shadow: 18px 18px 0 rgba(16, 19, 25, 0.07);
  padding: clamp(1.25rem, 4vw, 2rem);
}

.hero-plate img {
  width: min(100%, 360px);
  margin: 0 auto 2rem;
  filter: contrast(1.12);
}

.hero-plate dl {
  display: grid;
  gap: 0;
  margin: 0;
  border-top: 1px solid var(--line);
}

.hero-plate dl div {
  display: grid;
  grid-template-columns: 7rem minmax(0, 1fr);
  gap: 1rem;
  border-bottom: 1px solid var(--line);
  padding: 0.78rem 0;
}

.hero-plate dt {
  color: var(--signal);
  font-size: 0.72rem;
  font-weight: 850;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.hero-plate dd {
  margin: 0;
  color: var(--ink);
  font-size: 0.98rem;
  font-weight: 700;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.6rem;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  border: 1px solid var(--accent);
  background: var(--accent);
  color: var(--white);
  padding: 0.62rem 1rem;
  font-weight: 750;
  text-decoration: none;
  box-shadow: 4px 4px 0 var(--ink);
  transition: background 120ms ease, box-shadow 120ms ease, transform 120ms ease;
}

.button:hover {
  background: var(--accent-dark);
  color: var(--white);
  box-shadow: 2px 2px 0 var(--ink);
  transform: translate(2px, 2px);
}

.button.secondary {
  background: transparent;
  color: var(--accent);
  box-shadow: none;
}

.button.secondary:hover {
  background: var(--paper-deep);
  color: var(--accent-dark);
  box-shadow: none;
  transform: none;
}

.section {
  padding: clamp(3rem, 7vw, 5.5rem) 0;
}

.section + .section {
  border-top: 1px solid var(--line);
}

.section-compact {
  padding: clamp(2.5rem, 5vw, 4rem) 0;
}

.narrow {
  max-width: 760px;
}

.principle-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1px;
  border: 1px solid var(--line);
  background: var(--line);
}

.principle {
  background: rgba(255, 255, 255, 0.82);
  padding: clamp(1.15rem, 3vw, 1.75rem);
}

.principle span {
  display: inline-flex;
  margin-bottom: 1.8rem;
  color: var(--signal);
  font-size: 0.82rem;
  font-weight: 850;
  letter-spacing: 0.16em;
}

.principle h2 {
  font-size: clamp(1.55rem, 2.4vw, 2rem);
}

.feature-layout {
  display: grid;
  grid-template-columns: minmax(220px, 0.45fr) minmax(0, 0.75fr);
  gap: clamp(2rem, 6vw, 4.5rem);
  align-items: start;
}

.feature-layout > div:first-child {
  border-top: 5px solid var(--ink);
  padding-top: 1rem;
}

.book-card {
  display: grid;
  gap: 1rem;
  border: 1px solid var(--edge);
  background: var(--white);
  padding: clamp(1.25rem, 3vw, 2rem);
  box-shadow: 12px 12px 0 rgba(16, 19, 25, 0.07);
}

.featured-book {
  grid-template-columns: minmax(120px, 190px) minmax(0, 1fr);
  align-items: start;
}

.catalog-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(1.5rem, 4vw, 2.25rem);
}

.catalog-grid .book-card {
  grid-template-columns: minmax(112px, 0.34fr) minmax(0, 0.66fr);
  align-items: start;
}

.book-cover-link {
  display: block;
}

.book-cover {
  width: 100%;
  aspect-ratio: 2 / 3;
  border: 1px solid var(--edge);
  background: var(--paper-deep);
  box-shadow: 6px 6px 0 rgba(16, 19, 25, 0.09);
  object-fit: cover;
}

.book-card h2 {
  margin-bottom: 0.35rem;
}

.book-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin: 0.75rem 0;
  padding: 0;
  list-style: none;
}

.book-meta li {
  border: 1px solid var(--line);
  background: var(--paper-deep);
  color: var(--muted);
  padding: 0.18rem 0.5rem;
  font-size: 0.85rem;
  font-weight: 800;
}

.compact-actions {
  margin-top: 1rem;
}

.compact-actions .button {
  min-height: 38px;
  padding: 0.45rem 0.72rem;
  font-size: 0.92rem;
}

.book-detail {
  display: grid;
  grid-template-columns: minmax(180px, 310px) minmax(0, 680px);
  gap: clamp(2rem, 6vw, 4rem);
  align-items: start;
}

.book-detail-cover {
  position: sticky;
  top: 118px;
}

.book-detail-copy {
  max-width: 680px;
}

.note {
  border-left: 4px solid var(--signal);
  background: var(--white);
  padding: 1rem 1.1rem;
}

.page-header {
  position: relative;
  overflow: hidden;
  border-bottom: 1px solid var(--line);
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.68), rgba(244, 247, 248, 0)),
    linear-gradient(125deg, rgba(0, 127, 122, 0.08), transparent 45%),
    linear-gradient(25deg, transparent 62%, rgba(34, 89, 184, 0.1) 62% 100%);
  padding: clamp(3.25rem, 7vw, 6rem) 0;
  text-align: center;
}

.page-header::before {
  content: "";
  position: absolute;
  inset: 0;
  background: repeating-linear-gradient(90deg, transparent 0 92px, rgba(16, 19, 25, 0.045) 92px 93px);
  pointer-events: none;
}

.page-header > .container {
  position: relative;
}

.page-header .narrow {
  margin-right: auto;
  margin-left: auto;
}

.page-header h1,
.page-header .lede {
  margin-right: auto;
  margin-left: auto;
}

.page-header h1 {
  max-width: 900px;
  text-wrap: balance;
}

.content {
  padding: clamp(2.5rem, 6vw, 4rem) 0;
}

.content ul {
  padding-left: 1.2rem;
}

.content li + li {
  margin-top: 0.35rem;
}

.site-footer {
  border-top: 1px solid var(--line);
  background: var(--ink);
  color: var(--paper);
  padding: 2rem 0;
}

.footer-grid {
  display: flex;
  justify-content: space-between;
  gap: 2rem;
}

.footer-title {
  margin-bottom: 0.25rem;
  font-family: Georgia, "Times New Roman", serif;
  font-size: 1.25rem;
  font-weight: 700;
}

.site-footer p {
  max-width: 34rem;
  margin-bottom: 0;
  color: #dce4df;
}

.site-footer a {
  color: var(--paper);
}

@media (max-width: 760px) {
  body {
    font-size: 17px;
  }

  .header-inner,
  .footer-grid {
    align-items: center;
    flex-direction: column;
  }

  .header-inner {
    gap: 1rem;
    padding: 1rem 0;
  }

  .brand img {
    width: 170px;
  }

  .site-nav {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    width: 100%;
    gap: 0.5rem;
  }

  .site-nav a {
    border: 1px solid var(--line);
    background: rgba(255, 255, 255, 0.7);
    padding: 0.55rem 0.45rem;
    text-align: center;
  }

  .hero-inner {
    grid-template-columns: 1fr;
    min-height: auto;
    padding: clamp(3rem, 10vw, 4.5rem) 0;
  }

  .hero-plate {
    box-shadow: 8px 8px 0 rgba(16, 19, 25, 0.07);
  }

  .hero-plate img {
    width: min(100%, 320px);
  }

  .principle-grid,
  .feature-layout,
  .catalog-grid,
  .featured-book,
  .catalog-grid .book-card,
  .book-detail {
    grid-template-columns: 1fr;
  }

  .book-detail-cover {
    position: static;
    max-width: 240px;
  }

  .hero-plate dl div {
    grid-template-columns: 1fr;
    gap: 0.2rem;
  }
}