:root {
  --primary: #1e5fd6;
  --primary-dark: #1548a8;
  --accent: #00c2a8;
  --bg: #ffffff;
  --bg-soft: #f6f9ff;
  --bg-deep: #0b1a3a;
  --text: #1a2238;
  --text-soft: #5a6478;
  --border: #e3e9f2;
  --radius: 10px;
  --shadow: 0 8px 30px rgba(30, 95, 214, 0.08);
  --shadow-hover: 0 14px 40px rgba(30, 95, 214, 0.16);
  --maxw: 1120px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Segoe UI", Roboto, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--primary); text-decoration: none; transition: color .2s; }
a:hover { color: var(--primary-dark); }

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

.container {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 20px;
}

/* ===== Header / Nav ===== */
.site-header {
  position: sticky;
  top: 0;
  background: rgba(255,255,255,0.96);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--border);
  z-index: 50;
}
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 70px;
}
.logo {
  font-size: 22px;
  font-weight: 700;
  color: var(--text);
  letter-spacing: 1px;
}
.logo span { color: var(--primary); }
.nav-list {
  list-style: none;
  display: flex;
  gap: 34px;
  align-items: center;
}
.nav-list a {
  color: var(--text);
  font-weight: 500;
  font-size: 15px;
  position: relative;
}
.nav-list a:hover,
.nav-list a.active { color: var(--primary); }
.nav-list a.active::after {
  content: "";
  position: absolute;
  left: 0; right: 0; bottom: -6px;
  height: 3px;
  background: var(--primary);
  border-radius: 2px;
}
.nav-cta {
  background: var(--primary);
  color: #fff !important;
  padding: 9px 20px;
  border-radius: var(--radius);
  font-weight: 600;
}
.nav-cta:hover { background: var(--primary-dark); color: #fff !important; }
.nav-toggle { display: none; background: none; border: 0; font-size: 26px; cursor: pointer; color: var(--text); }

/* ===== Breadcrumb ===== */
.breadcrumb {
  background: var(--bg-soft);
  border-bottom: 1px solid var(--border);
  padding: 14px 0;
  font-size: 14px;
  color: var(--text-soft);
}
.breadcrumb a { color: var(--text-soft); }
.breadcrumb a:hover { color: var(--primary); }
.breadcrumb span.sep { margin: 0 8px; color: #b4bccb; }
.breadcrumb span.current { color: var(--text); }

/* ===== Hero ===== */
.hero {
  background:
    radial-gradient(1200px 500px at 10% -10%, rgba(30,95,214,.18), transparent 60%),
    radial-gradient(900px 400px at 110% 10%, rgba(0,194,168,.15), transparent 60%),
    linear-gradient(180deg, #0b1a3a 0%, #122a5c 100%);
  color: #fff;
  padding: 90px 0 100px;
  position: relative;
  overflow: hidden;
}
.hero h1 {
  font-size: 44px;
  line-height: 1.25;
  font-weight: 700;
  letter-spacing: .5px;
  margin-bottom: 20px;
}
.hero .subtitle {
  font-size: 18px;
  color: #cfd9f0;
  max-width: 780px;
  margin-bottom: 36px;
}
.hero-ctas { display: flex; gap: 16px; flex-wrap: wrap; }
.btn {
  display: inline-block;
  padding: 14px 30px;
  border-radius: var(--radius);
  font-weight: 600;
  font-size: 15px;
  cursor: pointer;
  border: 0;
  transition: all .25s;
  text-align: center;
}
.btn-primary { background: var(--accent); color: #0b1a3a; }
.btn-primary:hover { background: #00e8c9; color: #0b1a3a; transform: translateY(-2px); box-shadow: var(--shadow); }
.btn-ghost { background: transparent; color: #fff; border: 1px solid rgba(255,255,255,.4); }
.btn-ghost:hover { background: rgba(255,255,255,.1); color: #fff; }
.btn-dark { background: var(--primary); color: #fff; }
.btn-dark:hover { background: var(--primary-dark); color: #fff; transform: translateY(-2px); }

/* ===== Section ===== */
section { padding: 80px 0; }
.section-title {
  font-size: 32px;
  font-weight: 700;
  text-align: center;
  margin-bottom: 14px;
}
.section-sub {
  text-align: center;
  color: var(--text-soft);
  margin-bottom: 50px;
  font-size: 16px;
}

/* ===== Feature cards (home) ===== */
.dual-cards {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px;
}
.feature-card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 40px 36px;
  box-shadow: var(--shadow);
  transition: all .3s;
  position: relative;
  overflow: hidden;
}
.feature-card::before {
  content: "";
  position: absolute;
  top: 0; left: 0;
  width: 6px; height: 100%;
  background: linear-gradient(180deg, var(--primary), var(--accent));
}
.feature-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-hover); }
.feature-icon {
  width: 64px; height: 64px;
  border-radius: 14px;
  background: linear-gradient(135deg, rgba(30,95,214,.12), rgba(0,194,168,.12));
  display: flex; align-items: center; justify-content: center;
  margin-bottom: 22px;
  font-size: 30px;
}
.feature-card h3 {
  font-size: 22px;
  margin-bottom: 12px;
  font-weight: 700;
}
.feature-card .summary {
  color: var(--text-soft);
  margin-bottom: 24px;
  font-size: 15px;
  min-height: 50px;
}
.feature-card .link-more {
  font-weight: 600;
  color: var(--primary);
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
.feature-card .link-more::after { content: "→"; transition: transform .2s; }
.feature-card:hover .link-more::after { transform: translateX(4px); }

/* ===== Trust strip ===== */
.trust-section { background: var(--bg-soft); }
.trust-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 30px;
  margin-top: 30px;
}
.trust-item {
  background: #fff;
  padding: 28px 20px;
  border-radius: var(--radius);
  text-align: center;
  border: 1px solid var(--border);
}
.trust-item .num {
  font-size: 34px;
  font-weight: 700;
  color: var(--primary);
  display: block;
  margin-bottom: 6px;
}
.trust-item .lbl { font-size: 14px; color: var(--text-soft); }
.cert-row {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  justify-content: center;
  margin-top: 30px;
}
.cert-badge {
  background: #fff;
  border: 1px solid var(--border);
  padding: 10px 20px;
  border-radius: 999px;
  font-size: 14px;
  font-weight: 500;
  color: var(--text);
}

/* ===== FAQ ===== */
.faq-section { background: #fff; }
.faq-list { max-width: 820px; margin: 0 auto; }
.faq-item {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 14px;
  background: #fff;
  overflow: hidden;
  transition: box-shadow .2s;
}
.faq-item[open] { box-shadow: var(--shadow); }
.faq-question {
  padding: 20px 24px;
  font-weight: 600;
  font-size: 16px;
  cursor: pointer;
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: var(--text);
}
.faq-question::-webkit-details-marker { display: none; }
.faq-question::after {
  content: "+";
  font-size: 22px;
  color: var(--primary);
  transition: transform .2s;
  font-weight: 300;
}
.faq-item[open] .faq-question::after { content: "−"; }
.faq-answer {
  padding: 0 24px 22px;
  color: var(--text-soft);
  font-size: 15px;
}
.faq-answer p { margin-bottom: 10px; }
.faq-answer a { font-weight: 600; }

/* ===== HowTo steps ===== */
.howto-wrap { background: var(--bg-soft); }
.howto-list {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 22px;
  margin-top: 10px;
}
.howto-step {
  background: #fff;
  padding: 30px 24px;
  border-radius: var(--radius);
  border-top: 4px solid var(--primary);
  position: relative;
  box-shadow: var(--shadow);
}
.step-num {
  display: inline-flex;
  width: 40px; height: 40px;
  border-radius: 50%;
  background: var(--primary);
  color: #fff;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  margin-bottom: 16px;
}
.howto-step h3 { font-size: 18px; margin-bottom: 10px; }
.howto-step p { color: var(--text-soft); font-size: 14px; }

/* ===== Deep FAQ (three big questions) ===== */
.deep-faq-group {
  margin-bottom: 40px;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 16px;
  overflow: hidden;
  box-shadow: var(--shadow);
}
.deep-faq-title {
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  color: #fff;
  padding: 22px 28px;
  font-size: 19px;
  font-weight: 700;
}
.deep-faq-body { padding: 10px 20px 24px; }
.deep-faq-body .faq-item { border-left: 3px solid var(--accent); margin-top: 14px; }

/* ===== Page intro (sub pages) ===== */
.page-intro {
  background: linear-gradient(135deg, #0b1a3a 0%, #1a3a7a 100%);
  color: #fff;
  padding: 60px 0 70px;
  position: relative;
}
.page-intro h1 {
  font-size: 36px;
  line-height: 1.3;
  margin-bottom: 16px;
  font-weight: 700;
}
.page-intro p {
  font-size: 17px;
  color: #c7d4ee;
  max-width: 820px;
}

/* ===== Article (encryption stack) ===== */
.article-block {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 44px;
  box-shadow: var(--shadow);
}
.encrypt-stack {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
  margin: 30px 0;
}
.encrypt-layer {
  border-radius: var(--radius);
  padding: 28px 24px;
  color: #fff;
  position: relative;
}
.encrypt-layer .layer-tag {
  display: inline-block;
  background: rgba(255,255,255,.25);
  padding: 4px 12px;
  border-radius: 999px;
  font-size: 12px;
  margin-bottom: 14px;
}
.encrypt-layer h3 { font-size: 20px; margin-bottom: 10px; }
.encrypt-layer ul { list-style: none; padding: 0; }
.encrypt-layer li { font-size: 14px; opacity: .95; margin-bottom: 4px; }
.layer-app { background: linear-gradient(135deg, #1e5fd6, #00c2a8); }
.layer-trans { background: linear-gradient(135deg, #5b3cc4, #1e5fd6); }
.layer-net { background: linear-gradient(135deg, #0b1a3a, #1e5fd6); }

/* ===== CTA band ===== */
.cta-band {
  background: linear-gradient(135deg, #0b1a3a, #1e5fd6);
  color: #fff;
  padding: 70px 0;
  text-align: center;
}
.cta-band h2 { font-size: 30px; margin-bottom: 14px; }
.cta-band p { color: #cfd9f0; margin-bottom: 30px; }

/* ===== About ===== */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 50px;
  align-items: center;
}
.about-text h2 { font-size: 28px; margin-bottom: 18px; }
.about-text p { color: var(--text-soft); margin-bottom: 14px; }
.about-stats { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
.about-stat {
  background: var(--bg-soft);
  padding: 24px;
  border-radius: var(--radius);
  text-align: center;
}
.about-stat .v { font-size: 32px; font-weight: 700; color: var(--primary); }
.about-stat .l { color: var(--text-soft); font-size: 14px; }
.team-list {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 30px;
}
.team-card {
  background: #fff;
  border: 1px solid var(--border);
  padding: 24px;
  border-radius: var(--radius);
  text-align: center;
}
.team-avatar {
  width: 80px; height: 80px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: #fff;
  display: flex; align-items: center; justify-content: center;
  margin: 0 auto 14px;
  font-size: 30px;
  font-weight: 700;
}
.team-card h4 { font-size: 17px; margin-bottom: 4px; }
.team-card .role { color: var(--primary); font-weight: 600; font-size: 13px; margin-bottom: 8px; }
.team-card p { font-size: 13px; color: var(--text-soft); }

/* ===== Contact form ===== */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
}
.form-wrap {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 40px;
  box-shadow: var(--shadow);
}
.form-group { margin-bottom: 20px; }
.form-group label {
  display: block;
  font-weight: 600;
  margin-bottom: 8px;
  font-size: 14px;
}
.form-group input,
.form-group select,
.form-group textarea {
  width: 100%;
  padding: 12px 14px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 15px;
  font-family: inherit;
  transition: border-color .2s;
  background: #fff;
}
.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(30,95,214,.12);
}
.form-group textarea { resize: vertical; min-height: 120px; }
.contact-info {
  background: var(--bg-soft);
  padding: 40px;
  border-radius: 16px;
}
.contact-info h3 { font-size: 22px; margin-bottom: 22px; }
.contact-info .info-item {
  display: flex;
  gap: 14px;
  margin-bottom: 20px;
  align-items: flex-start;
}
.contact-info .info-icon {
  width: 40px; height: 40px;
  border-radius: 10px;
  background: var(--primary);
  color: #fff;
  display: flex; align-items: center; justify-content: center;
  flex-shrink: 0;
  font-size: 18px;
}
.contact-info .info-label { font-size: 13px; color: var(--text-soft); }
.contact-info .info-value { font-weight: 600; color: var(--text); }

/* ===== Footer ===== */
.site-footer {
  background: var(--bg-deep);
  color: #b7c2dc;
  padding: 60px 0 0;
}
.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1fr;
  gap: 40px;
  padding-bottom: 40px;
  border-bottom: 1px solid rgba(255,255,255,.08);
}
.footer-col h4 { color: #fff; font-size: 16px; margin-bottom: 18px; }
.footer-col ul { list-style: none; padding: 0; }
.footer-col li { margin-bottom: 10px; }
.footer-col a { color: #b7c2dc; font-size: 14px; }
.footer-col a:hover { color: #fff; }
.footer-col p { font-size: 14px; line-height: 1.7; }
.footer-bottom {
  text-align: center;
  padding: 22px 0;
  font-size: 13px;
  color: #8793b3;
}

/* ===== Responsive ===== */
@media (max-width: 880px) {
  .nav-list { display: none; }
  .nav-toggle { display: block; }
  .hero { padding: 60px 0 70px; }
  .hero h1 { font-size: 30px; }
  section { padding: 60px 0; }
  .section-title { font-size: 26px; }
  .dual-cards { grid-template-columns: 1fr; }
  .trust-grid { grid-template-columns: repeat(2, 1fr); }
  .howto-list { grid-template-columns: 1fr; }
  .encrypt-stack { grid-template-columns: 1fr; }
  .about-grid { grid-template-columns: 1fr; }
  .contact-grid { grid-template-columns: 1fr; }
  .team-list { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: 30px; }
  .page-intro h1 { font-size: 26px; }
  .form-wrap, .contact-info { padding: 28px; }
}