:root {
  --paper: #f5f0e8;
  --ink: #201a15;
  --muted: #74695f;
  --clay: #a34f32;
  --clay-dark: #763724;
  --moss: #5f7460;
  --gold: #d7a64a;
  --line: rgba(32, 26, 21, 0.16);
  --shadow: 0 24px 60px rgba(32, 26, 21, 0.16);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: Inter, "Microsoft YaHei", "PingFang SC", system-ui, sans-serif;
  line-height: 1.6;
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  min-height: 68px;
  padding: 0 32px;
  background: rgba(245, 240, 232, 0.88);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(18px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  letter-spacing: 0;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 36px;
  height: 36px;
  color: #fff;
  background: var(--clay);
  border-radius: 50%;
  font-size: 13px;
}

.nav-links {
  display: flex;
  gap: 22px;
  color: var(--muted);
  font-size: 14px;
}

.nav-links a:hover {
  color: var(--clay);
}

.hero {
  position: relative;
  min-height: calc(100vh - 68px);
  display: grid;
  align-items: end;
  overflow: hidden;
  background: #1b1713;
}

.hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background:
    linear-gradient(90deg, rgba(22, 17, 13, 0.82), rgba(22, 17, 13, 0.2) 58%, rgba(22, 17, 13, 0.1)),
    linear-gradient(0deg, rgba(22, 17, 13, 0.82), transparent 42%);
  pointer-events: none;
}

.hero-media {
  position: absolute;
  inset: 0;
}

.hero-media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
  filter: saturate(1.04) contrast(1.03);
}

.hero-copy {
  position: relative;
  z-index: 1;
  width: min(920px, calc(100% - 48px));
  padding: 0 0 9vh clamp(24px, 6vw, 88px);
  color: #fff;
}

.kicker {
  margin: 0 0 12px;
  color: var(--gold);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0;
  text-transform: uppercase;
}

.hero h1 {
  margin: 0;
  max-width: 820px;
  font-size: clamp(42px, 8vw, 104px);
  line-height: 1.02;
  letter-spacing: 0;
}

.hero p:not(.kicker) {
  max-width: 680px;
  margin: 22px 0 0;
  color: rgba(255, 255, 255, 0.86);
  font-size: clamp(16px, 2vw, 22px);
}

.hero-actions,
.button-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 18px;
  border: 1px solid var(--line);
  border-radius: 999px;
  font: inherit;
  font-weight: 800;
  cursor: pointer;
  transition: transform 160ms ease, background 160ms ease, color 160ms ease;
}

.button:hover {
  transform: translateY(-2px);
}

.button.primary {
  color: #fff;
  background: var(--clay);
  border-color: var(--clay);
}

.button.ghost {
  color: var(--ink);
  background: rgba(255, 255, 255, 0.68);
}

.button.ghost.light {
  color: #fff;
  background: rgba(255, 255, 255, 0.12);
  border-color: rgba(255, 255, 255, 0.28);
}

.overview,
.gallery,
.downloads {
  padding: clamp(56px, 8vw, 104px) clamp(22px, 5vw, 72px);
}

.section-heading {
  max-width: 760px;
  margin-bottom: 32px;
}

.section-heading h2,
.viewer-copy h2 {
  margin: 0;
  font-size: clamp(30px, 4.5vw, 56px);
  line-height: 1.08;
  letter-spacing: 0;
}

.info-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}

.info-grid article {
  min-height: 210px;
  padding: 24px;
  background: rgba(255, 255, 255, 0.48);
  border: 1px solid var(--line);
  border-radius: 8px;
}

.info-grid span {
  color: var(--clay);
  font-weight: 900;
}

.info-grid h3 {
  margin: 42px 0 8px;
  font-size: 22px;
}

.info-grid p,
.viewer-copy p,
.download-list small {
  color: var(--muted);
}

.pdf-section {
  display: grid;
  grid-template-columns: minmax(280px, 0.36fr) minmax(0, 0.64fr);
  gap: clamp(22px, 4vw, 56px);
  align-items: center;
  padding: clamp(44px, 7vw, 92px) clamp(22px, 5vw, 72px);
  border-top: 1px solid var(--line);
}

.pdf-section.dark {
  color: #fff;
  background: #201a15;
  border-color: rgba(255, 255, 255, 0.12);
}

.pdf-section.dark .viewer-copy p {
  color: rgba(255, 255, 255, 0.72);
}

.viewer-copy {
  max-width: 520px;
}

.pdf-frame {
  min-height: 72vh;
  overflow: hidden;
  background: #111;
  border: 1px solid rgba(255, 255, 255, 0.16);
  border-radius: 8px;
  box-shadow: var(--shadow);
}

.pdf-frame.pale {
  background: #ece3d8;
  border-color: var(--line);
}

.pdf-frame iframe {
  display: block;
  width: 100%;
  height: 72vh;
  min-height: 560px;
  border: 0;
  background: #fff;
}

.pdf-frame.is-placeholder {
  position: relative;
  display: grid;
  place-items: center;
  padding: 24px;
}

.placeholder-image {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.56;
}

.pdf-frame.is-placeholder > div {
  position: relative;
  z-index: 1;
  display: grid;
  gap: 8px;
  text-align: center;
}

.pdf-frame.is-placeholder strong {
  font-size: clamp(32px, 6vw, 88px);
  line-height: 1;
  letter-spacing: 0;
}

.pdf-frame.is-placeholder span {
  color: rgba(255, 255, 255, 0.68);
}

.pdf-frame.pale.is-placeholder span {
  color: var(--muted);
}

.download-list {
  display: grid;
  gap: 12px;
  max-width: 920px;
}

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

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

.gallery figure {
  margin: 0;
  overflow: hidden;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 8px;
}

.gallery img {
  display: block;
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
}

.gallery figcaption {
  padding: 12px 14px;
  color: var(--muted);
  font-size: 14px;
}

.download-list a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 20px 22px;
  background: rgba(255, 255, 255, 0.56);
  border: 1px solid var(--line);
  border-radius: 8px;
}

.download-list span {
  font-weight: 900;
}

.site-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 28px 32px;
  color: var(--muted);
  border-top: 1px solid var(--line);
}

@media (max-width: 900px) {
  .site-header {
    align-items: flex-start;
    flex-direction: column;
    padding: 14px 20px;
  }

  .nav-links {
    width: 100%;
    overflow-x: auto;
    padding-bottom: 4px;
  }

  .hero {
    min-height: 720px;
  }

  .hero-copy {
    width: 100%;
    padding: 0 22px 52px;
  }

  .info-grid,
  .gallery-grid,
  .pdf-section {
    grid-template-columns: 1fr;
  }

  .pdf-frame,
  .pdf-frame iframe {
    min-height: 520px;
    height: 66vh;
  }
}

@media (max-width: 560px) {
  .nav-links {
    gap: 16px;
    font-size: 13px;
  }

  .button {
    width: 100%;
  }

  .download-list a,
  .site-footer {
    align-items: flex-start;
    flex-direction: column;
  }
}