:root {
  --indigo-900: #1e1b4b;
  --indigo-800: #312e81;
  --indigo-700: #4338ca;
  --indigo-600: #4f46e5;
  --purple-600: #7c3aed;
  --purple-500: #8b5cf6;
  --purple-400: #a78bfa;
  --violet-glow: rgba(139, 92, 246, 0.45);
  --face-top: linear-gradient(145deg, #6366f1 0%, #7c3aed 55%, #5b21b6 100%);
  --face-left: #3730a3;
  --face-right: #4338ca;
  --text: #ede9fe;
  --text-soft: rgba(237, 233, 254, 0.74);
  --radius: 0.35rem;
  --iso-depth: 14px;
  --font-body: "Outfit", "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-display: "Outfit", "Noto Sans SC", sans-serif;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 88px; }

body {
  margin: 0;
  font-family: var(--font-body);
  color: var(--text);
  background: var(--indigo-900);
  line-height: 1.78;
  font-size: 16px;
  min-height: 100vh;
  overflow-x: hidden;
}

/* Isometric grid background */
.iso-bg {
  position: fixed;
  inset: 0;
  z-index: -1;
  background:
    radial-gradient(ellipse 80% 60% at 20% 10%, rgba(124, 58, 237, 0.28) 0%, transparent 55%),
    radial-gradient(ellipse 70% 50% at 85% 75%, rgba(79, 70, 229, 0.22) 0%, transparent 50%),
    linear-gradient(165deg, #0f0a2e 0%, var(--indigo-900) 45%, #1a1147 100%);
}
.iso-bg::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(30deg, rgba(99, 102, 241, 0.06) 12%, transparent 12.5%, transparent 87%, rgba(99, 102, 241, 0.06) 87.5%, rgba(99, 102, 241, 0.06)),
    linear-gradient(150deg, rgba(99, 102, 241, 0.06) 12%, transparent 12.5%, transparent 87%, rgba(99, 102, 241, 0.06) 87.5%, rgba(99, 102, 241, 0.06));
  background-size: 48px 84px;
  opacity: 0.55;
  transform: skewY(-6deg) scale(1.2);
  transform-origin: center;
}

img { max-width: 100%; height: auto; display: block; }
a { color: var(--purple-400); text-decoration: none; transition: color 0.2s; }
a:hover { color: #ddd6fe; text-decoration: underline; }

.container {
  width: min(1140px, 92vw);
  margin-inline: auto;
}

/* Isometric block utility */
.iso-block {
  position: relative;
  background: var(--face-top);
  border-radius: var(--radius);
  transform: perspective(900px) rotateX(8deg) rotateY(-4deg);
  transform-style: preserve-3d;
  box-shadow:
    var(--iso-depth) var(--iso-depth) 0 var(--face-left),
    calc(var(--iso-depth) * 2) calc(var(--iso-depth) * 2) 0 rgba(30, 27, 75, 0.85),
    0 24px 48px rgba(0, 0, 0, 0.35),
    inset 0 1px 0 rgba(255, 255, 255, 0.12);
  transition: transform 0.35s ease, box-shadow 0.35s ease;
}
.iso-block::before {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: linear-gradient(135deg, rgba(255,255,255,0.14) 0%, transparent 42%, rgba(0,0,0,0.08) 100%);
  pointer-events: none;
}
.iso-block:hover {
  transform: perspective(900px) rotateX(5deg) rotateY(-2deg) translateY(-6px);
  box-shadow:
    calc(var(--iso-depth) + 4px) calc(var(--iso-depth) + 4px) 0 var(--face-left),
    calc(var(--iso-depth) * 2 + 6px) calc(var(--iso-depth) * 2 + 6px) 0 rgba(30, 27, 75, 0.9),
    0 32px 56px var(--violet-glow),
    inset 0 1px 0 rgba(255, 255, 255, 0.16);
}

.iso-block-inner {
  position: relative;
  z-index: 1;
  padding: 2rem 2.25rem;
  background: rgba(49, 46, 129, 0.55);
  border: 1px solid rgba(167, 139, 250, 0.22);
  border-radius: calc(var(--radius) - 2px);
  margin: 3px;
  backdrop-filter: blur(6px);
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 200;
  padding: 0.65rem 0;
  background: rgba(15, 10, 46, 0.82);
  backdrop-filter: blur(16px);
  border-bottom: 2px solid rgba(99, 102, 241, 0.35);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.25);
}
.header-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}
.brand {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  color: var(--text);
  font-weight: 600;
  font-size: 1.05rem;
  text-decoration: none;
}
.brand b {
  background: linear-gradient(135deg, var(--purple-400), var(--indigo-600));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  font-weight: 700;
}
.brand img {
  border-radius: 10px;
  box-shadow: 4px 4px 0 var(--face-left), 0 0 18px var(--violet-glow);
  transform: rotate(-3deg);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  padding: 0;
  border: 1px solid rgba(167, 139, 250, 0.3);
  border-radius: 8px;
  background: rgba(67, 56, 202, 0.35);
  cursor: pointer;
}
.nav-toggle span {
  display: block;
  width: 20px;
  height: 2px;
  margin-inline: auto;
  background: var(--text);
  border-radius: 2px;
  transition: transform 0.25s, opacity 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: 0.25rem 0.5rem;
  list-style: none;
  margin: 0;
  padding: 0;
}
.site-nav a {
  color: var(--text-soft);
  font-size: 0.9rem;
  font-weight: 500;
  padding: 0.45rem 1rem;
  border-radius: 6px;
  border: 1px solid transparent;
  text-decoration: none;
  transition: background 0.2s, border-color 0.2s, transform 0.2s;
}
.site-nav a:hover,
.site-nav a.active {
  color: var(--text);
  background: rgba(99, 102, 241, 0.35);
  border-color: rgba(167, 139, 250, 0.4);
  transform: translateY(-2px);
  box-shadow: 3px 3px 0 var(--face-left);
}

/* Ads */
.ads-top-bar {
  padding: 0.6rem 0;
  background: rgba(49, 46, 129, 0.45);
  border-bottom: 1px solid rgba(99, 102, 241, 0.25);
}
#ads {
  display: flex;
  justify-content: center;
  align-items: flex-start;
  flex-wrap: wrap;
  background: transparent;
  margin: 10px 0;
  gap: 0.5rem;
}
#ads > div,
#ads .ads-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 70px;
}
#ads img {
  width: 65px;
  height: 65px;
  object-fit: cover;
  border-radius: 12px;
  box-shadow: 4px 4px 0 var(--face-left);
  transition: transform 180ms ease;
  border: 1px solid rgba(167, 139, 250, 0.3);
}
#ads a { display: inline-block; text-decoration: none; }
#ads img:hover { transform: translate(-2px, -4px); }
#ads figcaption,
#ads .caption {
  height: 15px;
  font-size: 11px;
  color: var(--text-soft);
  text-align: center;
  max-width: 100px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  margin-top: 4px;
}
.applist-title {
  text-align: center;
  font-size: 0.88rem;
  color: var(--text-soft);
}

/* Hero isometric */
.hero-iso {
  padding: 3rem 0 2rem;
}
.hero-iso-grid {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: 2.5rem;
  align-items: center;
}
.hero-badge {
  display: inline-block;
  padding: 0.35rem 1rem;
  background: rgba(79, 70, 229, 0.45);
  border: 1px solid rgba(167, 139, 250, 0.4);
  border-radius: 6px;
  font-size: 0.8rem;
  letter-spacing: 0.05em;
  margin-bottom: 1rem;
  color: #ddd6fe;
  box-shadow: 3px 3px 0 var(--face-left);
  transform: skewX(-3deg);
}
.hero-iso h1 {
  font-family: var(--font-display);
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  line-height: 1.28;
  margin: 0 0 1.15rem;
  font-weight: 700;
  color: #f5f3ff;
  text-shadow: 2px 2px 0 var(--indigo-800);
}
.hero-iso .lead {
  font-size: 1.02rem;
  color: var(--text-soft);
  margin: 0;
}
.hero-visual-wrap {
  transform: perspective(800px) rotateY(-8deg) rotateX(4deg);
}
.hero-visual-wrap img {
  border-radius: var(--radius);
  border: 2px solid rgba(167, 139, 250, 0.35);
  box-shadow:
    12px 12px 0 var(--face-left),
    24px 24px 0 rgba(30, 27, 75, 0.7),
    0 20px 40px var(--violet-glow);
}

/* Partner isometric chips */
.partner-strip { padding: 1rem 0 0.5rem; }
.partner-iso {
  padding: 1.1rem 1.35rem;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.75rem;
  --iso-depth: 8px;
}
.partner-iso a {
  display: inline-flex;
  align-items: center;
  padding: 0.55rem 1.25rem;
  background: linear-gradient(145deg, #6366f1, #7c3aed);
  border-radius: 6px;
  color: #f5f3ff;
  font-size: 0.88rem;
  font-weight: 500;
  text-decoration: none;
  box-shadow: 5px 5px 0 var(--face-left), 0 8px 20px rgba(0,0,0,0.25);
  transform: perspective(600px) rotateX(6deg);
  transition: transform 0.2s, box-shadow 0.2s;
}
.partner-iso a:hover {
  transform: perspective(600px) rotateX(4deg) translateY(-3px);
  box-shadow: 7px 7px 0 var(--face-left), 0 12px 28px var(--violet-glow);
  color: #fff;
  text-decoration: none;
}

/* Anchor pills */
.anchor-pills {
  padding: 1rem 0 1.25rem;
  overflow-x: auto;
}
.pill-scroll {
  display: flex;
  flex-wrap: nowrap;
  gap: 0.55rem;
  padding-bottom: 0.35rem;
}
.pill-scroll a {
  flex-shrink: 0;
  padding: 0.48rem 1.05rem;
  background: rgba(67, 56, 202, 0.5);
  border: 1px solid rgba(167, 139, 250, 0.3);
  border-radius: 6px;
  font-size: 0.84rem;
  color: var(--text-soft);
  text-decoration: none;
  box-shadow: 3px 3px 0 var(--face-left);
  transition: background 0.2s, transform 0.2s;
}
.pill-scroll a:hover {
  background: rgba(124, 58, 237, 0.45);
  color: var(--text);
  transform: translateY(-2px);
}

/* Content sections */
.section-stack {
  padding: 0 0 3rem;
  display: flex;
  flex-direction: column;
  gap: 2rem;
}
.iso-panel { --iso-depth: 12px; }
.iso-panel h2 {
  font-family: var(--font-display);
  font-size: clamp(1.35rem, 3vw, 1.85rem);
  margin: 0 0 1.1rem;
  font-weight: 600;
  color: #f5f3ff;
}
.prose { max-width: 72ch; }
.prose p { margin: 0 0 1rem; color: var(--text-soft); }
.prose ul, .prose ol { margin: 0 0 1rem; padding-left: 1.4rem; color: var(--text-soft); }
.prose li { margin-bottom: 0.4rem; }
.prose strong { color: var(--text); }
.prose h3 {
  font-size: 1.05rem;
  color: var(--purple-400);
  margin: 1.25rem 0 0.65rem;
}

.split-iso {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
  align-items: center;
}
.split-iso.reverse { direction: rtl; }
.split-iso.reverse > * { direction: ltr; }
.split-iso img {
  border-radius: var(--radius);
  border: 2px solid rgba(167, 139, 250, 0.3);
  box-shadow: 10px 10px 0 var(--face-left), 0 16px 32px rgba(0,0,0,0.3);
  transform: perspective(700px) rotateY(-6deg);
}

/* Isometric card grid */
.iso-card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(270px, 1fr));
  gap: 1.5rem;
  margin-top: 1.5rem;
}
.iso-card {
  --iso-depth: 10px;
  overflow: hidden;
}
.iso-card img {
  width: 100%;
  height: 155px;
  object-fit: cover;
  border-bottom: 2px solid rgba(167, 139, 250, 0.25);
}
.iso-card .card-body { padding: 1rem 1.2rem 1.25rem; }
.iso-card h3 {
  margin: 0 0 0.45rem;
  font-size: 1rem;
  color: #f5f3ff;
}
.iso-card p {
  margin: 0;
  font-size: 0.9rem;
  color: var(--text-soft);
}

/* FAQ isometric */
.faq-list {
  margin-top: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}
.faq-item {
  --iso-depth: 8px;
}
.faq-item .iso-block-inner { padding: 1.15rem 1.4rem; }
.faq-item h3 {
  margin: 0 0 0.45rem;
  font-size: 0.98rem;
  color: var(--purple-400);
}
.faq-item p { margin: 0; font-size: 0.93rem; color: var(--text-soft); }

/* Related reading */
.related-reading {
  margin-top: 0.5rem;
}
.related-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 1.25rem;
  margin-top: 1.25rem;
}
.related-item {
  --iso-depth: 9px;
}
.related-item .iso-block-inner {
  padding: 1.15rem 1.3rem;
  min-height: 120px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}
.related-item h3 {
  margin: 0 0 0.5rem;
  font-size: 0.95rem;
  color: #f5f3ff;
}
.related-item p {
  margin: 0 0 0.75rem;
  font-size: 0.86rem;
  color: var(--text-soft);
  flex: 1;
}
.related-item a.read-more {
  font-size: 0.84rem;
  font-weight: 600;
  color: var(--purple-400);
  text-decoration: none;
}
.related-item a.read-more:hover { color: #ddd6fe; }

/* Inner page hero */
.page-hero { padding: 2.25rem 0 1.25rem; }
.page-hero-inner { --iso-depth: 10px; }
.page-hero-inner .iso-block-inner { padding: 1.75rem 2rem; }
.page-hero h1 {
  font-family: var(--font-display);
  font-size: clamp(1.45rem, 3vw, 2rem);
  margin: 0.5rem 0 0;
  font-weight: 600;
  color: #f5f3ff;
}
.breadcrumb { font-size: 0.86rem; color: var(--text-soft); }
.breadcrumb a { color: var(--purple-400); }

/* Error pages */
.error-wrap {
  text-align: center;
  padding: 4rem 0 5rem;
}
.error-iso {
  display: inline-block;
  --iso-depth: 14px;
}
.error-iso .iso-block-inner { padding: 3rem 4rem; }
.error-wrap .code {
  font-family: var(--font-display);
  font-size: 5rem;
  font-weight: 700;
  margin: 0;
  line-height: 1;
  background: linear-gradient(135deg, var(--purple-400), var(--indigo-600));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  text-shadow: none;
  filter: drop-shadow(4px 4px 0 var(--face-left));
}
.error-wrap h1 { margin: 0.5rem 0 1rem; color: var(--text); }
.error-wrap p { color: var(--text-soft); }

/* Footer */
.site-footer {
  padding: 2rem 0 2.5rem;
  margin-top: 1rem;
  border-top: 2px solid rgba(99, 102, 241, 0.35);
  background: rgba(15, 10, 46, 0.75);
  font-size: 0.86rem;
  text-align: center;
  color: var(--text-soft);
}
.site-footer a { color: var(--purple-400); }
.footer-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1rem 1.5rem;
  margin-bottom: 1rem;
}
.footer-links a { text-decoration: none; }

@media (max-width: 860px) {
  .nav-toggle { display: flex; }
  .site-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: rgba(15, 10, 46, 0.95);
    backdrop-filter: blur(16px);
    border-bottom: 2px solid rgba(99, 102, 241, 0.35);
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s;
  }
  .site-nav.is-open { max-height: 320px; }
  .site-nav ul {
    flex-direction: column;
    padding: 1rem 1.25rem 1.25rem;
  }
  .hero-iso-grid,
  .split-iso { grid-template-columns: 1fr; }
  .split-iso.reverse { direction: ltr; }
  .iso-block { transform: perspective(900px) rotateX(4deg); }
  .iso-block-inner { padding: 1.5rem 1.35rem; }
  .header-row { position: relative; }
  #ads { flex-wrap: nowrap; overflow-x: auto; justify-content: flex-start; }
}