:root {
  --blueprint-bg: #1e3a5f;
  --blueprint-grid: rgba(0, 220, 255, 0.12);
  --blueprint-grid-major: rgba(0, 220, 255, 0.22);
  --cyan: #00dcff;
  --cyan-dim: #7ec8e3;
  --white: #e8f4fc;
  --white-dim: #a8c8dc;
  --accent: #00ffcc;
  --border: rgba(0, 220, 255, 0.45);
  --max: 1180px;
  --header-h: 64px;
  --font-mono: "JetBrains Mono", "Consolas", "Courier New", monospace;
  --font-sans: "Noto Sans SC", "Microsoft YaHei", sans-serif;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 48px);
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.82;
  color: var(--white);
  background-color: var(--blueprint-bg);
  background-image:
    linear-gradient(var(--blueprint-grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--blueprint-grid) 1px, transparent 1px),
    linear-gradient(var(--blueprint-grid-major) 1px, transparent 1px),
    linear-gradient(90deg, var(--blueprint-grid-major) 1px, transparent 1px);
  background-size: 20px 20px, 20px 20px, 100px 100px, 100px 100px;
  min-height: 100vh;
}

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

a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px dashed rgba(0, 220, 255, 0.4);
}
a:hover { color: var(--accent); border-bottom-color: var(--accent); }

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

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 500;
  background: rgba(30, 58, 95, 0.96);
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(8px);
}
.header-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: var(--header-h);
  gap: 1rem;
}
.brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  color: var(--cyan);
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 0.95rem;
  letter-spacing: 0.04em;
  text-decoration: none;
  border: none;
}
.brand:hover { color: var(--accent); border: none; }
.brand img { width: 36px; height: 36px; border: 1px solid var(--border); }
.brand b { color: var(--accent); font-weight: 700; }

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  width: 44px;
  height: 44px;
  padding: 10px;
  border: 1px solid var(--border);
  background: rgba(0, 220, 255, 0.06);
  cursor: pointer;
}
.nav-toggle span {
  height: 2px;
  background: var(--cyan);
  transition: 0.25s;
}
.nav-toggle.is-open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.is-open span:nth-child(2) { opacity: 0; }
.nav-toggle.is-open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

.site-nav ul {
  display: flex;
  flex-wrap: wrap;
  gap: 0.2rem 1.4rem;
  list-style: none;
  margin: 0;
  padding: 0;
}
.site-nav a {
  color: var(--white-dim);
  font-family: var(--font-mono);
  font-size: 0.82rem;
  font-weight: 500;
  text-decoration: none;
  border: none;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}
.site-nav a:hover,
.site-nav a.active { color: var(--accent); }

/* Ads */
.ads-top-bar {
  padding: 0.55rem 0;
  background: rgba(0, 0, 0, 0.18);
  border-bottom: 1px dashed var(--border);
}
#ads {
  display: flex;
  justify-content: center;
  align-items: flex-start;
  flex-wrap: wrap;
  background: transparent;
  margin: 8px 0;
  gap: 0.5rem;
}
#ads > div,
#ads .ads-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 70px;
  box-sizing: border-box;
}
#ads img {
  width: 65px;
  height: 65px;
  object-fit: cover;
  border-radius: 8px;
  border: 1px solid var(--border);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
  transition: transform 180ms ease, box-shadow 180ms ease;
  display: block;
  background: rgba(0, 220, 255, 0.08);
}
#ads a { display: inline-block; text-decoration: none; border: none; border-radius: 8px; }
#ads img:hover {
  transform: translateY(-3px) scale(1.04);
  box-shadow: 0 8px 20px rgba(0, 220, 255, 0.2);
}
#ads figcaption,
#ads .caption {
  height: 15px;
  font-size: 11px;
  color: var(--white-dim);
  text-align: center;
  max-width: 100px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  margin-top: 4px;
  font-family: var(--font-mono);
}
.applist-title {
  text-align: center;
  font-size: 0.82rem;
  color: var(--cyan-dim);
  font-family: var(--font-mono);
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

/* Blueprint drawing frame */
.bp-frame {
  position: relative;
  border: 1px solid var(--border);
  margin: 1.5rem 0;
  padding: 2rem 1.5rem 1.5rem;
  background: rgba(0, 20, 40, 0.25);
}
.bp-frame::before,
.bp-frame::after {
  content: "";
  position: absolute;
  width: 16px;
  height: 16px;
  border-color: var(--cyan);
  border-style: solid;
}
.bp-frame::before {
  top: -1px;
  left: -1px;
  border-width: 2px 0 0 2px;
}
.bp-frame::after {
  bottom: -1px;
  right: -1px;
  border-width: 0 2px 2px 0;
}

.dim-marker {
  position: absolute;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  color: var(--cyan-dim);
  letter-spacing: 0.08em;
  pointer-events: none;
}
.dim-top { top: -0.6rem; left: 50%; transform: translateX(-50%); }
.dim-left { left: -0.5rem; top: 50%; transform: translateY(-50%) rotate(-90deg); }
.dim-right { right: -0.5rem; top: 50%; transform: translateY(-50%) rotate(90deg); }

/* Title block (technical drawing title block) */
.title-block {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 1.5rem;
  padding: 2rem 0 1.5rem;
  border-bottom: 1px dashed var(--border);
  align-items: end;
}
.title-block-main h1 {
  font-family: var(--font-mono);
  font-size: clamp(1.4rem, 3.5vw, 2rem);
  margin: 0 0 0.75rem;
  line-height: 1.35;
  color: var(--white);
  font-weight: 700;
  letter-spacing: 0.02em;
}
.title-block-main .deck {
  font-size: 0.95rem;
  color: var(--white-dim);
  max-width: 42em;
  margin: 0;
}
.title-block-meta {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--cyan-dim);
  border: 1px solid var(--border);
  padding: 0.75rem 1rem;
  line-height: 1.6;
  min-width: 200px;
}
.title-block-meta dt { color: var(--cyan); margin-top: 0.4rem; }
.title-block-meta dt:first-child { margin-top: 0; }
.title-block-meta dd { margin: 0.1rem 0 0; }

/* External link strip */
.link-strip {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.6rem 1rem;
  padding: 1.25rem 0;
  border-bottom: 1px dashed var(--border);
}
.link-strip a {
  padding: 0.45rem 1rem;
  border: 1px dashed var(--cyan);
  color: var(--cyan);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 600;
  text-decoration: none;
  letter-spacing: 0.04em;
  background: rgba(0, 220, 255, 0.05);
}
.link-strip a:hover {
  background: rgba(0, 255, 204, 0.12);
  color: var(--accent);
  border-color: var(--accent);
}

/* Section nav chips */
.chip-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin: 1.25rem 0;
}
.chip-nav a {
  padding: 0.35rem 0.85rem;
  border: 1px dashed var(--border);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--white-dim);
  text-decoration: none;
  letter-spacing: 0.06em;
}
.chip-nav a:hover { border-color: var(--accent); color: var(--accent); }

/* Blueprint sections */
.bp-section {
  padding: 2.5rem 0;
  border-bottom: 1px dashed rgba(0, 220, 255, 0.2);
  position: relative;
}
.bp-section:nth-child(even) { background: rgba(0, 0, 0, 0.08); }

.section-tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.15em;
  color: var(--accent);
  border: 1px solid var(--accent);
  padding: 0.2rem 0.6rem;
  margin-bottom: 0.75rem;
}
.bp-section h2 {
  font-family: var(--font-mono);
  font-size: 1.45rem;
  margin: 0 0 1.25rem;
  line-height: 1.35;
  color: var(--cyan);
  font-weight: 700;
  letter-spacing: 0.03em;
}
.bp-section h3 {
  font-family: var(--font-mono);
  font-size: 1.05rem;
  color: var(--accent);
  margin: 1.5rem 0 0.75rem;
}

.bp-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
  align-items: start;
}
.bp-grid p { margin: 0 0 1rem; text-align: justify; color: var(--white-dim); }
.bp-grid strong { color: var(--white); }

.bp-annot {
  position: relative;
  padding-left: 1.5rem;
  border-left: 2px dashed var(--cyan);
  font-family: var(--font-mono);
  font-size: 0.88rem;
  color: var(--cyan-dim);
  font-style: italic;
  margin: 1.25rem 0;
  line-height: 1.7;
}
.bp-annot::before {
  content: "NOTE";
  position: absolute;
  left: -0.5rem;
  top: -0.5rem;
  font-size: 0.6rem;
  background: var(--blueprint-bg);
  padding: 0 0.3rem;
  color: var(--accent);
  font-style: normal;
  letter-spacing: 0.1em;
}

.feature-img {
  border: 1px solid var(--border);
  position: relative;
  background: rgba(0, 20, 40, 0.3);
}
.feature-img::after {
  content: attr(data-dim);
  position: absolute;
  bottom: 4px;
  right: 8px;
  font-family: var(--font-mono);
  font-size: 0.65rem;
  color: var(--cyan-dim);
}

.img-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  margin: 1.5rem 0;
}

/* Prose / subpages */
.page-hero {
  padding: 2rem 0;
  border-bottom: 1px dashed var(--border);
}
.page-hero h1 {
  font-family: var(--font-mono);
  margin: 0.5rem 0 0;
  font-size: 1.75rem;
  color: var(--cyan);
}
.breadcrumb {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--white-dim);
  letter-spacing: 0.04em;
}
.breadcrumb a { color: var(--white-dim); border: none; }
.breadcrumb a:hover { color: var(--accent); }

.prose p { margin: 0 0 1rem; color: var(--white-dim); }
.prose ul, .prose ol { margin: 0 0 1rem; padding-left: 1.4rem; color: var(--white-dim); }
.prose strong { color: var(--white); }
.prose h2 {
  font-family: var(--font-mono);
  font-size: 1.2rem;
  color: var(--cyan);
  margin: 1.5rem 0 0.75rem;
}

.related-read {
  margin-top: 2rem;
  padding: 1.25rem 1.5rem;
  border: 1px dashed var(--border);
  background: rgba(0, 220, 255, 0.04);
}
.related-read h2 {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--accent);
  letter-spacing: 0.12em;
  margin: 0 0 0.75rem;
  text-transform: uppercase;
}
.related-read ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1.5rem;
}
.related-read a {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--cyan);
}

.error-wrap { text-align: center; padding: 4rem 0; }
.error-wrap .code {
  font-size: 4rem;
  color: var(--accent);
  font-family: var(--font-mono);
  margin: 0;
  letter-spacing: 0.1em;
}

.site-footer {
  margin-top: 1rem;
  padding: 2rem 0;
  border-top: 1px dashed var(--border);
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--white-dim);
  letter-spacing: 0.04em;
}
.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem 2rem;
  margin-bottom: 1rem;
}
.footer-links a { color: var(--white-dim); border: none; }
.footer-links a:hover { color: var(--accent); }

@media (max-width: 900px) {
  .bp-grid { grid-template-columns: 1fr; }
  .img-row { grid-template-columns: 1fr; }
  .title-block { grid-template-columns: 1fr; }
}
@media (max-width: 768px) {
  .nav-toggle { display: flex; }
  .site-nav {
    position: fixed;
    inset: var(--header-h) 0 auto 0;
    background: rgba(30, 58, 95, 0.98);
    border-bottom: 1px solid var(--border);
    padding: 1rem;
    transform: translateY(-120%);
    opacity: 0;
    visibility: hidden;
    transition: 0.3s;
    box-shadow: 0 12px 32px rgba(0, 0, 0, 0.4);
  }
  .site-nav.is-open { transform: translateY(0); opacity: 1; visibility: visible; }
  .site-nav ul { flex-direction: column; }
  .site-nav a { display: block; padding: 0.65rem 0; border-bottom: 1px dashed rgba(0, 220, 255, 0.15); }
  .ads-top-bar .container { width: 100%; padding-inline: 0.75rem; }
  #ads {
    flex-wrap: nowrap;
    overflow-x: auto;
    scroll-snap-type: x proximity;
    justify-content: flex-start;
    -webkit-overflow-scrolling: touch;
  }
  #ads::-webkit-scrollbar { display: none; }
  #ads > div,
  #ads .ads-item {
    width: 84px;
    flex-shrink: 0;
    scroll-snap-align: center;
  }
}