/* =====================
   DESIGN TOKENS
===================== */
:root {
  --bg-light: #f5f5f7;
  --bg-white: #ffffff;
  --bg-dark: #050509;
  --bg-card-dark: #12121a;

  --text-main: #111827;
  --text-muted: #4b5563;
  --text-soft: #6b7280;
  --text-light: #e5e7eb;

  --border-subtle: #e5e7eb;
  --border-dark: #3f3f46;

  --accent: #111827;
  --accent-soft: rgba(15, 23, 42, 0.05);
  --accent-strong: rgba(15, 23, 42, 0.16);

  --radius-lg: 24px;
  --radius-md: 18px;
  --radius-pill: 999px;

  --shadow-soft: 0 18px 45px rgba(0,0,0,0.12);
  --shadow-strong: 0 26px 70px rgba(15,23,42,0.28);

  --transition-fast: 0.25s cubic-bezier(.4,.1,.2,1);
  --transition-slow: 0.6s cubic-bezier(.25,.1,.25,1);
}

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

html, body {
  margin: 0;
  padding: 0;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Inter",
    "Helvetica Neue", Arial, sans-serif;
  background: radial-gradient(circle at top, #f9fafb 0, #ffffff 40%, #f5f5f7 100%);
  color: var(--text-main);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  transition: background var(--transition-slow), color var(--transition-slow);
}

a {
  color: inherit;
}

.container {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 24px;
}

/* =====================
   HEADER
===================== */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 80px;
  background: radial-gradient(circle at top left,
      rgba(255,255,255,0.96),
      rgba(248,250,252,0.94));
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid rgba(229,231,235,0.9);
  z-index: 40;
  transition: background var(--transition-fast), border-color var(--transition-fast);
}

.header-inner {
  height: 80px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  font-size: 16px;
  font-weight: 800;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  padding: 6px 14px;
  border-radius: 999px;
  border: 1px solid rgba(148,163,184,0.6);
  background: radial-gradient(circle at top left,
      rgba(255,255,255,0.96),
      rgba(248,250,252,0.98));
}

.desktop-nav {
  display: flex;
  align-items: center;
  gap: 10px;
}

.nav-pill {
  padding: 8px 16px;
  border-radius: var(--radius-pill);
  border: 1px solid rgba(209,213,219,0.9);
  background: rgba(255,255,255,0.96);
  text-decoration: none;
  font-size: 14px;
  color: var(--text-main);
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: background var(--transition-fast),
    box-shadow var(--transition-fast),
    transform var(--transition-fast),
    border-color var(--transition-fast);
}

.nav-pill span {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  opacity: 0.6;
}

.nav-pill:hover {
  box-shadow: var(--shadow-soft);
  border-color: rgba(148,163,184,0.95);
  transform: translateY(-1px);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

.nav-btn {
  padding: 7px 14px;
  border-radius: var(--radius-pill);
  border: 1px solid rgba(209,213,219,0.9);
  background: rgba(255,255,255,0.96);
  font-size: 13px;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: background var(--transition-fast),
    box-shadow var(--transition-fast),
    transform var(--transition-fast),
    border-color var(--transition-fast);
}

.nav-btn:hover {
  box-shadow: 0 12px 34px rgba(148,163,184,0.35);
  transform: translateY(-1px);
  border-color: rgba(148,163,184,0.95);
}

/* mobile menu button */
.mobile-menu-btn {
  display: none;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-pill);
  border: 1px solid rgba(209,213,219,0.9);
  background: rgba(255,255,255,0.96);
  font-size: 20px;
  align-items: center;
  justify-content: center;
}

/* mobile dropdown */
.mobile-menu {
  display: none;
  position: fixed;
  top: 80px;
  left: 0;
  right: 0;
  background: rgba(248,250,252,0.98);
  border-bottom: 1px solid rgba(229,231,235,0.9);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  z-index: 35;
}

.mobile-menu-inner {
  max-width: 1120px;
  margin: 0 auto;
  padding: 10px 20px 16px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.mobile-link {
  padding: 10px 10px;
  border-radius: 14px;
  text-decoration: none;
  display: flex;
  justify-content: space-between;
  font-size: 15px;
  color: var(--text-main);
}

.mobile-link span:last-child {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  color: var(--text-soft);
}

/* show mobile menu */
.mobile-menu.open {
  display: block;
}

/* =====================
   HERO
===================== */
.hero {
  padding-top: 140px;
  padding-bottom: 52px;
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
  gap: 52px;
  align-items: center;
}

.hero-heading {
  font-size: 42px;
  font-weight: 800;
  letter-spacing: 0.02em;
  margin: 0 0 10px;
}

.hero-sub {
  font-size: 18px;
  font-weight: 500;
  color: var(--text-muted);
  margin-bottom: 8px;
}

.hero-sub-cn {
  font-size: 14px;
  color: var(--text-soft);
  margin-bottom: 16px;
}

.hero-body {
  font-size: 15px;
  color: var(--text-muted);
  line-height: 1.9;
  max-width: 560px;
}

.hero-actions {
  margin-top: 24px;
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* buttons */
.btn-primary,
.btn-ghost {
  border-radius: var(--radius-pill);
  padding: 9px 20px;
  border: 1px solid transparent;
  font-size: 14px;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  cursor: pointer;
  text-decoration: none;
  transition: background var(--transition-fast),
    color var(--transition-fast),
    transform var(--transition-fast),
    box-shadow var(--transition-fast),
    border-color var(--transition-fast);
}

.btn-primary {
  background: radial-gradient(circle at top left, #111827, #020617);
  color: #f9fafb;
  box-shadow: var(--shadow-strong);
}

.btn-primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 28px 72px rgba(15,23,42,0.5);
}

.btn-ghost {
  background: rgba(255,255,255,0.98);
  color: var(--text-main);
  border-color: rgba(209,213,219,0.95);
}

.btn-ghost:hover {
  background: #0f172a;
  color: #f9fafb;
  border-color: transparent;
}

/* hero side */
.hero-side {
  border-radius: var(--radius-lg);
  border: 1px solid rgba(229,231,235,0.9);
  background: radial-gradient(circle at top left,
      rgba(255,255,255,0.96),
      rgba(248,250,252,0.98));
  box-shadow: var(--shadow-soft);
  padding: 18px 18px 20px;
}

.hero-tag {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  font-size: 12px;
  padding: 4px 10px;
  border-radius: var(--radius-pill);
  background: rgba(15,23,42,0.05);
  color: var(--text-main);
}

.hero-tag-dot {
  width: 7px;
  height: 7px;
  border-radius: 999px;
  background: #22c55e;
}

.hero-meta {
  margin: 14px 0 0;
  padding-left: 18px;
  font-size: 13px;
  color: var(--text-soft);
}

.hero-meta li {
  margin-bottom: 5px;
}

/* =====================
   SECTION LAYOUT
===================== */
.section {
  padding: 40px 0 40px;
}

.section-header {
  margin-bottom: 22px;
}

.section-kicker {
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: #9ca3af;
  margin-bottom: 6px;
}

.section-title {
  font-size: 22px;
  font-weight: 700;
  margin: 0 0 8px;
}

.section-sub {
  font-size: 14px;
  color: var(--text-soft);
  max-width: 540px;
}

/* grids & cards */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2,minmax(0,1fr));
  gap: 22px;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3,minmax(0,1fr));
  gap: 22px;
}

.card {
  border-radius: var(--radius-md);
  padding: 18px 20px 20px;
  border: 1px solid var(--border-subtle);
  background: rgba(255,255,255,0.98);
  box-shadow: 0 18px 46px rgba(15,23,42,0.06);
  transition: transform var(--transition-fast),
    box-shadow var(--transition-fast),
    border-color var(--transition-fast),
    background var(--transition-fast);
}

.card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-soft);
  border-color: rgba(148,163,184,0.9);
}

.card-tag {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  color: #9ca3af;
  margin-bottom: 8px;
}

.card-title {
  font-size: 16px;
  font-weight: 600;
  margin: 0 0 6px;
}

.card-body {
  font-size: 14px;
  color: var(--text-muted);
  line-height: 1.8;
}

.point-cn {
  margin-top: 4px;
  font-size: 13px;
  color: #9ca3af;
}

/* special layout for ecosystem “universe map” */
.universe-grid {
  display: grid;
  grid-template-columns: minmax(0,1.25fr) minmax(0,1fr);
  gap: 22px;
}

.orbit-list {
  list-style: none;
  padding-left: 0;
  margin: 10px 0 0;
  font-size: 14px;
  color: var(--text-muted);
}

.orbit-list li {
  margin-bottom: 6px;
}

/* =====================
   CALLOUT
===================== */
.callout {
  border-radius: 26px;
  padding: 22px 22px 20px;
  background: linear-gradient(135deg,#0f172a,#020617);
  color: var(--text-light);
  box-shadow: var(--shadow-strong);
}

.callout h2 {
  margin: 0 0 8px;
  font-size: 22px;
  font-weight: 700;
}

.callout p {
  margin: 0 0 14px;
  font-size: 14px;
  line-height: 1.9;
}

.callout-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
}

.callout-tag {
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  padding: 4px 10px;
  border-radius: var(--radius-pill);
  border: 1px solid rgba(148,163,184,0.8);
}

/* =====================
   FOOTER
===================== */
.site-footer {
  border-top: 1px solid rgba(229,231,235,0.9);
  padding: 22px 0 26px;
  text-align: center;
  font-size: 13px;
  color: #9ca3af;
  margin-top: 40px;
}

/* =====================
   SCROLL REVEAL
===================== */
.reveal {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity var(--transition-slow),
    transform var(--transition-slow);
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* =====================
   DARK MODE
===================== */
body.dark {
  background: radial-gradient(circle at top,#020617 0,#020617 40%,#020617 100%);
  color: #e5e7eb;
}

body.dark .site-header {
  background: radial-gradient(circle at top left,
      rgba(15,23,42,0.96),
      rgba(15,23,42,0.94));
  border-color: rgba(55,65,81,0.9);
}

body.dark .logo {
  border-color: rgba(75,85,99,0.9);
  background: radial-gradient(circle at top left,
      rgba(15,23,42,0.98),
      rgba(17,24,39,0.98));
  color: #e5e7eb;
}

body.dark .nav-pill,
body.dark .nav-btn {
  background: rgba(15,23,42,0.96);
  color: #e5e7eb;
  border-color: rgba(55,65,81,0.95);
}

body.dark .mobile-menu {
  background: rgba(15,23,42,0.98);
  border-color: rgba(55,65,81,0.9);
}

body.dark .mobile-link span:last-child {
  color: #9ca3af;
}

body.dark .hero-side {
  background: radial-gradient(circle at top left,
      rgba(15,23,42,0.98),
      rgba(15,23,42,0.96));
  border-color: rgba(55,65,81,0.95);
}

body.dark .hero-tag {
  background: rgba(15,23,42,0.9);
  color: #e5e7eb;
}

body.dark .hero-meta {
  color: #9ca3af;
}

body.dark .card {
  background: var(--bg-card-dark);
  border-color: rgba(55,65,81,0.9);
  box-shadow: 0 20px 60px rgba(0,0,0,0.7);
}

body.dark .card-body {
  color: #d1d5db;
}

body.dark .section-sub {
  color: #9ca3af;
}

body.dark .callout {
  background: linear-gradient(135deg,#020617,#020617);
  border: 1px solid rgba(75,85,99,0.9);
}

body.dark .site-footer {
  border-color: rgba(55,65,81,0.9);
}

/* lock scroll when mobile menu open */
body.menu-open {
  overflow: hidden;
}

/* =====================
   RESPONSIVE
===================== */
@media (max-width: 960px) {
  .hero-grid {
    grid-template-columns: minmax(0,1fr);
    gap: 28px;
  }

  .hero-side {
    order: -1;
  }

  .grid-3 {
    grid-template-columns: minmax(0,1fr);
  }

  .universe-grid {
    grid-template-columns: minmax(0,1fr);
  }
}

@media (max-width: 768px) {
  .desktop-nav {
    display: none;
  }

  .mobile-menu-btn {
    display: inline-flex;
  }

  .hero {
    padding-top: 124px;
    padding-bottom: 32px;
  }

  .hero-heading {
    font-size: 32px;
  }

  .container {
    padding: 0 18px;
  }

  .grid-2 {
    grid-template-columns: minmax(0,1fr);
  }
}