/* Mobile-first responsive design for a high-end cold-wallet safety documentation center */
:root {
  --primary: rgb(70,139,223);
  --primary-dark: #2269bd;
  --primary-soft: #edf6ff;
  --primary-line: #d8eaff;
  --ink: #14213d;
  --muted: #5d6b82;
  --soft: #f7fbff;
  --panel: rgba(255,255,255,.88);
  --border: #e4eef8;
  --shadow: 0 18px 55px rgba(47, 101, 164, .10);
  --radius: 20px;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at top left, rgba(70,139,223,.12), transparent 36rem),
    linear-gradient(180deg, #ffffff 0%, #f7fbff 55%, #ffffff 100%);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", Arial, sans-serif;
  line-height: 1.7;
  overflow-x: hidden;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; height: auto; display: block; }
p { margin: 0 0 1rem; color: var(--muted); }
h1, h2, h3 { margin: 0 0 .75rem; line-height: 1.2; letter-spacing: -.02em; }
h1 { font-size: clamp(2.1rem, 8vw, 4.2rem); }
h2 { font-size: clamp(1.55rem, 4.5vw, 2.35rem); }
h3 { font-size: 1.08rem; }
.section { padding: 3.8rem 0; }
.container { width: min(1120px, calc(100% - 2rem)); margin: 0 auto; }
.narrow-container { width: min(880px, calc(100% - 2rem)); margin: 0 auto; }
.gradient-bg { background: linear-gradient(135deg, rgba(70,139,223,.10), rgba(255,255,255,.95)); }
.eyebrow, .doc-badge {
  display: inline-flex; align-items: center; gap: .4rem;
  padding: .34rem .7rem; border-radius: 999px;
  color: var(--primary-dark); background: var(--primary-soft);
  border: 1px solid var(--primary-line); font-size: .84rem; font-weight: 700;
}
.site-header {
  position: sticky; top: 0; z-index: 20;
  background: rgba(255,255,255,.86); backdrop-filter: blur(18px);
  border-bottom: 1px solid rgba(216,234,255,.78);
}
.header-inner {
  width: min(1180px, calc(100% - 1.25rem)); margin: 0 auto; min-height: 72px;
  display: flex; align-items: center; justify-content: space-between; gap: 1rem;
}
.logo, .footer-logo {
  display: inline-flex; align-items: center; gap: .65rem;
  font-weight: 800; color: #0e2342; white-space: nowrap;
}
.logo img, .footer-logo img { width: 38px; height: 38px; border-radius: 12px; }
.mobile-nav-toggle {
  border: 1px solid var(--primary-line); color: var(--primary-dark);
  background: #fff; padding: .55rem .8rem; border-radius: 999px; font-weight: 800;
}
.site-nav {
  display: none; width: 100%; position: absolute; left: 0; right: 0; top: 72px;
  padding: .7rem 1rem 1rem; background: rgba(255,255,255,.97);
  border-bottom: 1px solid var(--border); box-shadow: var(--shadow);
}
.site-nav.is-open { display: grid; gap: .35rem; }
.site-nav a { padding: .75rem .85rem; border-radius: 14px; color: var(--muted); font-weight: 700; }
.site-nav a:hover, .site-nav a.active { color: var(--primary-dark); background: var(--primary-soft); }
.docs-hero, .hero-banner { padding: 4rem 0 2.5rem; }
.docs-hero-grid, .hero-layout { display: grid; gap: 2rem; align-items: center; }
.hero-copy { display: grid; gap: 1rem; }
.hero-copy p { font-size: 1.05rem; }
.hero-tags, .status-tags { display: flex; flex-wrap: wrap; gap: .65rem; }
.hero-tags span, .status-tags span {
  display: inline-flex; align-items: center; padding: .44rem .68rem; border-radius: 999px;
  background: #fff; border: 1px solid var(--primary-line);
  color: var(--primary-dark); font-size: .86rem; font-weight: 700;
}
.download-btn {
  display: inline-flex; justify-content: center; align-items: center; width: fit-content; min-height: 48px;
  padding: .82rem 1.35rem; border-radius: 999px; background: var(--primary);
  color: #fff; font-weight: 850; box-shadow: 0 12px 28px rgba(70,139,223,.28);
  transition: transform .18s ease, box-shadow .18s ease, background .18s ease; border: 0;
}
.download-btn:hover { transform: translateY(-1px); background: var(--primary-dark); box-shadow: 0 16px 36px rgba(70,139,223,.32); }
.hero-visual {
  background: linear-gradient(145deg, rgba(255,255,255,.94), rgba(237,246,255,.94));
  border: 1px solid var(--primary-line); border-radius: 28px; padding: 1rem; box-shadow: var(--shadow);
}
.app-stage { display: grid; grid-template-columns: 1fr; gap: .9rem; align-items: center; }
.app-card { background: #fff; border: 1px solid var(--border); border-radius: 26px; padding: .95rem; box-shadow: 0 16px 40px rgba(47,101,164,.10); }
.app-card img { margin: 0 auto; max-height: 420px; object-fit: contain; }
.status-stack { display: grid; gap: .75rem; }
.status-card { background: rgba(255,255,255,.90); border: 1px solid var(--border); border-radius: 18px; padding: .9rem; }
.status-card strong { display: block; color: #102b4f; margin-bottom: .15rem; }
.status-card small { color: var(--muted); }
.safety-strip {
  width: min(1120px, calc(100% - 2rem)); margin: 0 auto 2.2rem;
  display: grid; gap: .6rem; padding: 1rem; border-radius: 18px;
  background: #edf6ff; border: 1px solid var(--primary-line);
}
.safety-strip span { color: #244767; font-weight: 750; }
.safety-notice, .tip-box {
  padding: 1rem 1rem 1rem 1.15rem; background: #edf6ff;
  border-left: 4px solid var(--primary); border-radius: 16px; color: #244767;
}
.docs-layout { display: grid; gap: 1.2rem; align-items: start; }
.docs-sidebar { background: var(--panel); border: 1px solid var(--border); border-radius: var(--radius); padding: 1rem; box-shadow: var(--shadow); }
.docs-sidebar strong { display: block; margin-bottom: .75rem; color: #102b4f; }
.docs-sidebar nav { display: grid; gap: .35rem; }
.docs-sidebar a { display: block; padding: .7rem .8rem; border-radius: 12px; color: var(--muted); font-weight: 750; }
.docs-sidebar a:hover { color: var(--primary-dark); background: var(--primary-soft); }
.docs-main { display: grid; gap: 1.25rem; }
.doc-section, .security-panel, .cta-section, .article-panel, .download-panel, .about-panel {
  background: rgba(255,255,255,.92); border: 1px solid var(--border);
  border-radius: 24px; padding: 1.2rem; box-shadow: var(--shadow);
}
.section-title { display: flex; flex-direction: column; gap: .35rem; margin-bottom: 1.1rem; }
.section-title .num { color: var(--primary-dark); font-weight: 900; letter-spacing: .08em; font-size: .82rem; }
.docs-steps, .process-steps, .steps { display: grid; gap: .8rem; }
.step-item, .process-step {
  display: grid; gap: .35rem; padding: 1rem; background: #fbfdff;
  border: 1px solid var(--border); border-radius: 18px;
}
.step-num {
  display: inline-flex; align-items: center; justify-content: center; width: 2.1rem; height: 2.1rem;
  border-radius: 50%; background: var(--primary); color: #fff; font-weight: 900;
}
.step-item a, .document-card a, .category-card a, .risk-item a, .scenario-card a, .read-link {
  color: var(--primary-dark); font-weight: 850;
}
.docs-category-grid, .category-grid, .category-nav, .feature-grid, .risk-grid, .scenario-grid, .doc-card-grid {
  display: grid; gap: .9rem;
}
.category-card, .document-card, .scenario-card, .risk-item, .feature-card, .faq-item {
  background: #fbfdff; border: 1px solid var(--border); border-radius: 18px; padding: 1rem;
}
.category-card:hover, .document-card:hover, .scenario-card:hover, .risk-item:hover, .feature-card:hover {
  transform: translateY(-2px); transition: transform .2s ease;
}
.principle-list { display: grid; gap: .75rem; }
.principle {
  display: grid; grid-template-columns: auto 1fr; gap: .85rem; align-items: start;
  padding: 1rem; border: 1px solid var(--border); border-radius: 18px; background: #fbfdff;
}
.principle b {
  display: inline-flex; width: 2.15rem; height: 2.15rem; align-items: center; justify-content: center;
  border-radius: 12px; background: var(--primary-soft); color: var(--primary-dark);
}
.security-layout { display: grid; gap: 1rem; }
.security-list { display: grid; gap: .65rem; }
.security-list li, .check-list li { margin-bottom: .35rem; color: var(--muted); }
.risk-item strong { display: block; color: #102b4f; margin-bottom: .25rem; }
.risk-item em { display: block; color: var(--primary-dark); font-style: normal; font-weight: 800; margin: .55rem 0; }
.faq-list { display: grid; gap: .75rem; }
.faq-item summary { cursor: pointer; font-weight: 850; color: #102b4f; }
.faq-item p { margin-top: .65rem; margin-bottom: 0; }
.cta-section { text-align: center; background: linear-gradient(135deg, rgba(70,139,223,.12), rgba(255,255,255,.96)), #fff; }
.cta-section .download-btn { margin-top: .6rem; }
.page-hero { padding: 3.2rem 0 1.3rem; }
.page-hero-card {
  background: rgba(255,255,255,.92); border: 1px solid var(--border);
  border-radius: 26px; padding: 1.25rem; box-shadow: var(--shadow);
}
.page-hero-card p { font-size: 1.02rem; }
.article-layout { display: grid; gap: 1rem; align-items: start; }
.article-panel { display: grid; gap: 1rem; }
.article-panel h2 { font-size: 1.35rem; }
.aside-panel { background: var(--primary-soft); border: 1px solid var(--primary-line); border-radius: 22px; padding: 1rem; }
.check-list { padding-left: 1.1rem; margin: .4rem 0 0; }
.inline-grid { display: grid; gap: .75rem; }
.mini-card { padding: .9rem; border: 1px solid var(--border); border-radius: 16px; background: #fff; }
.download-panel { text-align: center; }
.download-only { display: grid; justify-items: center; gap: 1rem; }
.site-footer { margin-top: 3rem; padding: 2.8rem 0; border-top: 1px solid var(--border); background: #f7fbff; }
.footer-grid { display: grid; gap: 1.4rem; }
.site-footer h2 { font-size: 1rem; margin-bottom: .5rem; }
.site-footer a:not(.footer-logo) { display: block; color: var(--muted); padding: .15rem 0; }
@media (min-width: 640px) {
  .safety-strip { grid-template-columns: repeat(3, 1fr); }
  .docs-category-grid, .category-grid, .category-nav, .feature-grid, .risk-grid, .scenario-grid, .doc-card-grid, .inline-grid { grid-template-columns: repeat(2, 1fr); }
  .app-stage { grid-template-columns: 1.1fr .9fr; }
}
@media (min-width: 880px) {
  .mobile-nav-toggle { display: none; }
  .site-nav {
    display: flex; position: static; width: auto; padding: 0; background: transparent;
    border: 0; box-shadow: none; gap: .2rem; align-items: center;
  }
  .site-nav a { padding: .58rem .72rem; font-size: .95rem; }
  .docs-hero-grid, .hero-layout { grid-template-columns: minmax(0, 1fr) minmax(360px, .88fr); }
  .docs-layout { grid-template-columns: 250px minmax(0, 1fr); gap: 1.4rem; }
  .docs-sidebar { position: sticky; top: 92px; }
  .doc-section, .security-panel, .cta-section, .article-panel, .download-panel, .about-panel { padding: 1.65rem; }
  .docs-category-grid, .category-grid, .feature-grid, .risk-grid { grid-template-columns: repeat(3, 1fr); }
  .security-layout, .article-layout { grid-template-columns: minmax(0, 1fr) 300px; }
  .docs-steps { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1.3fr .7fr .9fr; }
}
@media (min-width: 1120px) {
  .docs-hero { padding-top: 5.4rem; }
  .docs-steps { grid-template-columns: 1fr; }
  .step-item { grid-template-columns: auto 1fr auto; align-items: center; }
}