/* ============ CSS Variables ============ */
:root {
  --bg:       #021823;
  --bg2:      #052330;
  --bg3:      #072c3d;
  --surface:  rgba(255,255,255,0.03);
  --surface2: rgba(255,255,255,0.06);
  --border:   rgba(0,217,178,0.12);
  --border2:  rgba(0,217,178,0.28);
  --teal:     #00D9B2;
  --teal2:    #00B8D4;
  --teal3:    #5EEAD4;
  --text:     #E0F2F1;
  --text2:    #7AA5A0;
  --text-muted: #7AA5A0;
  --radius:   14px;
  --radius2:  10px;
  --grad:     linear-gradient(135deg, #00D9B2, #00B8D4);
  --grad-soft:linear-gradient(135deg, rgba(0,217,178,0.10), rgba(0,184,212,0.06));
  --grad-text:linear-gradient(135deg, #00D9B2, #5EEAD4);
  --shadow:   0 4px 24px rgba(0,0,0,0.4);
  --shadow2:  0 8px 40px rgba(0,217,178,0.10);
  --transition: .3s cubic-bezier(.4,0,.2,1);
  --max-width: 1120px;
}

/* ============ Reset ============ */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .animate-on-scroll { opacity: 1; transform: none; transition: none; }
}
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  overflow-x: hidden;
}
a { color: inherit; text-decoration: none; transition: color var(--transition); }
img { max-width: 100%; height: auto; display: block; }
ul { list-style: none; }
button { cursor: pointer; font-family: inherit; }

/* ============ Background Decoration ============ */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 50% at 50% -10%, rgba(0,217,178,0.08), transparent),
    radial-gradient(ellipse 60% 40% at 80% 100%, rgba(0,184,212,0.05), transparent);
  pointer-events: none;
  z-index: 0;
}

/* ============ Container ============ */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  position: relative;
  z-index: 1;
}

/* ============ Header ============ */
.header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  padding: 16px 0;
  background: rgba(2,24,35,0.82);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border);
  transition: padding var(--transition);
}
.header.scrolled { padding: 10px 0; }
.header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 1.1rem;
  font-weight: 700;
  color: #fff;
  white-space: nowrap;
}
.logo img { width: 32px; height: 32px; border-radius: 8px; }
.nav {
  display: flex;
  align-items: center;
  gap: 28px;
}
.nav a {
  font-size: 0.9rem;
  color: var(--text2);
  position: relative;
  white-space: nowrap;
}
.nav a:hover, .nav a.active { color: #fff; }
.nav a.active::after {
  content: "";
  position: absolute;
  bottom: -6px; left: 0; right: 0;
  height: 2px;
  background: var(--grad);
  border-radius: 2px;
}
.nav a.cta {
  background: var(--grad);
  color: #021823;
  font-weight: 600;
  padding: 8px 18px;
  border-radius: var(--radius2);
}
.nav a.cta:hover { opacity: .9; }
.nav a.cta::after { display: none; }

/* Mobile menu button */
.mobile-menu-btn {
  display: none;
  font-size: 1.5rem;
  color: #fff;
  background: none;
  border: none;
  padding: 4px;
}

/* Mobile overlay */
#mobileOverlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.6);
  backdrop-filter: blur(4px);
  z-index: 99;
}
#mobileOverlay.open { display: block; }

/* Mobile nav */
.mobile-nav {
  position: fixed;
  top: 0; right: -300px;
  width: 280px;
  height: 100vh;
  background: var(--bg2);
  z-index: 101;
  padding: 64px 24px 24px;
  transition: right var(--transition);
  border-left: 1px solid var(--border);
  overflow-y: auto;
}
.mobile-nav.open { right: 0; }
.mobile-nav a {
  display: block;
  padding: 14px 0;
  font-size: 1rem;
  color: var(--text);
  border-bottom: 1px solid var(--border);
}
.mobile-nav a:hover { color: var(--teal3); }
.mobile-nav a.mobile-cta {
  background: var(--grad);
  color: #021823;
  font-weight: 600;
  text-align: center;
  border-radius: var(--radius2);
  padding: 14px;
  margin-top: 16px;
  border-bottom: none;
}
.mobile-nav-close {
  position: absolute;
  top: 16px; right: 20px;
  font-size: 1.8rem;
  color: #fff;
  background: none;
  border: none;
}

/* ============ Buttons ============ */
.btn {
  display: inline-block;
  padding: 12px 28px;
  border-radius: var(--radius2);
  font-size: 0.92rem;
  font-weight: 600;
  transition: all var(--transition);
  border: none;
}
.btn-primary {
  background: var(--grad);
  color: #021823;
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: var(--shadow2); }
.btn-lg { padding: 16px 40px; font-size: 1.05rem; }
.btn-outline {
  background: none;
  color: var(--teal3);
  border: 1px solid var(--border2);
}
.btn-outline:hover { background: var(--surface2); border-color: var(--teal); }

/* ============ Page Hero ============ */
.page-hero {
  padding: 140px 0 64px;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.page-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(circle 400px at 50% 30%, rgba(0,217,178,0.07), transparent);
  pointer-events: none;
}
.page-hero h1 {
  font-size: 2.4rem;
  font-weight: 800;
  color: #fff;
  margin-bottom: 16px;
  position: relative;
}
.page-hero p {
  font-size: 1rem;
  color: var(--text2);
  max-width: 640px;
  margin: 0 auto;
  position: relative;
}

/* ============ Grad Text ============ */
.grad-text {
  background: var(--grad-text);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

/* ============ Section ============ */
.section {
  padding: 80px 0;
  position: relative;
  z-index: 1;
}
.section-title {
  text-align: center;
  margin-bottom: 48px;
}
.section-title h2 {
  font-size: 1.8rem;
  font-weight: 700;
  color: #fff;
  margin-bottom: 12px;
}
.section-title p {
  font-size: 0.95rem;
  color: var(--text2);
  max-width: 560px;
  margin: 0 auto;
}

/* ============ CTA Section ============ */
.cta-section {
  padding: 72px 0;
  text-align: center;
  position: relative;
  z-index: 1;
}
.cta-section .container {
  background: var(--grad-soft);
  border: 1px solid var(--border2);
  border-radius: 24px;
  padding: 56px 40px;
}
.cta-section h2 {
  font-size: 1.8rem;
  font-weight: 700;
  color: #fff;
  margin-bottom: 12px;
}
.cta-section p {
  font-size: 0.95rem;
  color: var(--text2);
  margin-bottom: 28px;
}

/* ============ Footer ============ */
.footer {
  background: var(--bg2);
  border-top: 1px solid var(--border);
  padding: 56px 0 24px;
  position: relative;
  z-index: 1;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 40px;
}
.footer-brand .logo { margin-bottom: 16px; }
.footer-brand p {
  font-size: 0.85rem;
  color: var(--text2);
  margin-bottom: 16px;
  line-height: 1.7;
}
.footer-tags { display: flex; flex-wrap: wrap; gap: 6px; }
.tag {
  font-size: 0.72rem;
  padding: 4px 10px;
  border-radius: 6px;
  background: var(--surface2);
  color: var(--teal3);
  border: 1px solid var(--border);
}
.footer-col h4 {
  font-size: 0.9rem;
  font-weight: 600;
  color: #fff;
  margin-bottom: 16px;
}
.footer-col ul li { margin-bottom: 10px; }
.footer-col ul li a {
  font-size: 0.85rem;
  color: var(--text2);
}
.footer-col ul li a:hover { color: var(--teal3); }
.footer-bottom {
  text-align: center;
  padding-top: 24px;
  border-top: 1px solid var(--border);
}
.footer-bottom p {
  font-size: 0.8rem;
  color: var(--text2);
}
.footer-bottom a { color: var(--teal3); }

/* ============ Scroll Animation ============ */
.animate-on-scroll {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity .6s ease, transform .6s ease;
}
.animate-on-scroll.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ============ Responsive ============ */
@media (max-width: 968px) {
  .nav { display: none; }
  .mobile-menu-btn { display: block; }
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 32px; }
}
@media (max-width: 600px) {
  .page-hero { padding: 120px 0 48px; }
  .page-hero h1 { font-size: 1.7rem; }
  .section { padding: 56px 0; }
  .section-title h2 { font-size: 1.4rem; }
  .cta-section .container { padding: 40px 24px; }
  .cta-section h2 { font-size: 1.4rem; }
  .footer-grid { grid-template-columns: 1fr; gap: 28px; }
  .footer-bottom p { font-size: 0.75rem; }
  .btn-lg { padding: 14px 32px; font-size: 0.95rem; }
}