:root {
  --primary: #1668F4;
  --primary-700: #0A3D91;
  --primary-600: #0A59F7;
  --primary-100: #E8F1FE;
  --accent: #8FC1FF;
  --bg: #FFFFFF;
  --bg-muted: #F6F8FB;
  --bg-dark: #052458;
  --text: #0D1829;
  --text-muted: #5A6779;
  --text-inverse: #FFFFFF;
  --border: #E2E8F0;
  --shadow: 0 10px 40px rgba(10, 61, 145, 0.10);
  --radius: 24px;
  --radius-sm: 12px;
  --container: 1120px;
  --header-h: 72px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
}

.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
}

a {
  color: var(--primary);
  text-decoration: none;
}

.section {
  padding: 96px 0;
}

.section-title {
  font-size: 2.25rem;
  line-height: 1.2;
  text-align: center;
  margin: 0 0 12px;
}

.section-subtitle {
  font-size: 1.125rem;
  color: var(--text-muted);
  text-align: center;
  margin: 0 auto 56px;
  max-width: 640px;
}

.section-dark {
  background: linear-gradient(180deg, var(--bg-dark) 0%, #082D66 100%);
  color: var(--text-inverse);
}

.section-dark .section-subtitle {
  color: var(--accent);
}

.section-muted {
  background: var(--bg-muted);
}

/* Header */
.site-header {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 100;
  height: var(--header-h);
  background: rgba(255, 255, 255, 0.82);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid rgba(226, 232, 240, 0.6);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-h);
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--text);
  font-weight: 700;
  font-size: 1.125rem;
}

.brand-logo {
  width: 40px;
  height: 40px;
  border-radius: 10px;
}

.brand-name small {
  font-weight: 500;
  color: var(--text-muted);
  margin-left: 6px;
}

.nav-links {
  display: flex;
  gap: 32px;
}

.nav-links a {
  color: var(--text);
  font-size: 0.9375rem;
  font-weight: 500;
  opacity: 0.85;
  transition: opacity 0.2s, color 0.2s;
}

.nav-links a:hover {
  opacity: 1;
  color: var(--primary);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  padding: 8px;
  cursor: pointer;
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: transform 0.2s, opacity 0.2s;
}

/* Hero */
.hero {
  padding-top: calc(var(--header-h) + 80px);
  padding-bottom: 100px;
  background: radial-gradient(circle at 80% 20%, var(--primary-100) 0%, transparent 45%),
              linear-gradient(180deg, var(--bg) 0%, var(--bg-muted) 100%);
  overflow: hidden;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  background: var(--primary-100);
  color: var(--primary-700);
  border-radius: 999px;
  font-size: 0.8125rem;
  font-weight: 600;
  margin-bottom: 24px;
}

.hero h1 {
  font-size: 3.25rem;
  line-height: 1.1;
  margin: 0 0 20px;
  letter-spacing: -0.02em;
}

.lead {
  font-size: 1.125rem;
  color: var(--text-muted);
  margin: 0 0 32px;
}

.hero-actions {
  display: flex;
  gap: 16px;
  margin-bottom: 32px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 24px;
  border-radius: 12px;
  font-size: 0.9375rem;
  font-weight: 600;
  transition: transform 0.15s, box-shadow 0.15s, background 0.15s;
}

.btn-primary {
  background: var(--primary);
  color: var(--text-inverse);
  box-shadow: 0 6px 20px rgba(22, 104, 244, 0.30);
}

.btn-primary:hover {
  background: var(--primary-600);
  transform: translateY(-1px);
  box-shadow: 0 10px 28px rgba(22, 104, 244, 0.38);
}

.btn-secondary {
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--border);
}

.btn-secondary:hover {
  background: var(--bg-muted);
}

.btn-large {
  padding: 16px 32px;
  font-size: 1rem;
}

.hero-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  list-style: none;
  padding: 0;
  margin: 0;
}

.hero-tags li {
  font-size: 0.8125rem;
  color: var(--text-muted);
  background: rgba(255, 255, 255, 0.7);
  border: 1px solid var(--border);
  padding: 6px 12px;
  border-radius: 999px;
}

/* Phone mockup */
.hero-visual {
  display: flex;
  justify-content: center;
  align-items: center;
}

.phone-frame {
  width: 280px;
  height: 560px;
  border-radius: 40px;
  background: linear-gradient(180deg, #052458 0%, #0A3D91 100%);
  box-shadow: var(--shadow), 0 30px 80px rgba(10, 61, 145, 0.25);
  padding: 14px;
  position: relative;
  transform: rotate(-4deg);
}

.phone-frame::before {
  content: "";
  position: absolute;
  top: 18px;
  left: 50%;
  transform: translateX(-50%);
  width: 90px;
  height: 24px;
  background: rgba(0, 0, 0, 0.25);
  border-radius: 999px;
  z-index: 2;
}

.screen {
  height: 100%;
  border-radius: 30px;
  background: linear-gradient(180deg, #1668F4 0%, #0A3D91 100%);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 32px 24px;
  color: #fff;
  position: relative;
}

.screen::after {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 50% 30%, rgba(143, 193, 255, 0.2) 0%, transparent 60%);
  pointer-events: none;
}

.screen-header {
  text-align: center;
  margin-bottom: 32px;
  z-index: 1;
}

.issuer {
  display: block;
  font-size: 1.25rem;
  font-weight: 700;
  opacity: 0.95;
}

.account {
  font-size: 0.8125rem;
  opacity: 0.75;
}

.code-row {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin-bottom: 24px;
  z-index: 1;
}

.otp-code {
  font-size: 2.75rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  font-variant-numeric: tabular-nums;
}

.countdown {
  font-size: 0.875rem;
  opacity: 0.85;
  font-variant-numeric: tabular-nums;
}

.progress-ring {
  width: 120px;
  height: 120px;
  z-index: 1;
}

.progress-ring svg {
  transform: rotate(-90deg);
}

.progress-ring circle {
  fill: none;
  stroke-width: 10;
  stroke-linecap: round;
}

.progress-ring .track {
  stroke: rgba(255, 255, 255, 0.18);
}

.progress-ring .fill {
  stroke: #8FC1FF;
  stroke-dasharray: 339.292;
  stroke-dashoffset: 0;
  transition: stroke-dashoffset 1s linear, stroke 0.3s;
}

.screen-footer {
  margin-top: auto;
  font-size: 0.75rem;
  opacity: 0.65;
  z-index: 1;
}

/* Features */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.feature-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
  transition: transform 0.2s, box-shadow 0.2s;
}

.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow);
}

.feature-card .icon {
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  background: var(--primary-100);
  border-radius: 14px;
  margin-bottom: 20px;
}

.feature-card h3 {
  font-size: 1.125rem;
  margin: 0 0 10px;
}

.feature-card p {
  font-size: 0.9375rem;
  color: var(--text-muted);
  margin: 0;
}

/* Security */
.security-grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 64px;
  align-items: center;
}

.security-list {
  display: grid;
  gap: 28px;
}

.security-item h4 {
  font-size: 1.0625rem;
  margin: 0 0 6px;
  color: var(--text-inverse);
}

.security-item p {
  margin: 0;
  color: rgba(255, 255, 255, 0.75);
  font-size: 0.9375rem;
}

.lock-card {
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: var(--radius);
  padding: 48px 32px;
  text-align: center;
  backdrop-filter: blur(10px);
}

.lock-icon {
  font-size: 4rem;
  margin-bottom: 16px;
}

.lock-status {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 6px;
}

.lock-hint {
  font-size: 0.875rem;
  color: rgba(255, 255, 255, 0.65);
}

/* Backup */
.backup-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.backup-card {
  background: var(--bg-muted);
  border-radius: var(--radius);
  padding: 32px;
  position: relative;
  overflow: hidden;
}

.backup-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: var(--primary);
}

.backup-num {
  display: block;
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 16px;
}

.backup-card h3 {
  font-size: 1.125rem;
  margin: 0 0 10px;
}

.backup-card p {
  font-size: 0.9375rem;
  color: var(--text-muted);
  margin: 0;
}

/* Tech */
.tech-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  margin-bottom: 40px;
}

.tech-stat {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 28px;
  text-align: center;
}

.stat-value {
  display: block;
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 4px;
}

.stat-label {
  font-size: 0.875rem;
  color: var(--text-muted);
}

.tech-detail {
  text-align: center;
  color: var(--text-muted);
  max-width: 820px;
  margin: 0 auto;
}

/* Download */
.download-card {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-700) 100%);
  border-radius: var(--radius);
  padding: 64px 32px;
  text-align: center;
  color: var(--text-inverse);
  box-shadow: var(--shadow);
}

.download-logo {
  width: 80px;
  height: 80px;
  border-radius: 20px;
  margin-bottom: 24px;
}

.download-card h2 {
  font-size: 2rem;
  margin: 0 0 12px;
}

.download-card p {
  font-size: 1.0625rem;
  opacity: 0.9;
  margin: 0 auto 28px;
  max-width: 540px;
}

.download-meta {
  font-size: 0.8125rem !important;
  opacity: 0.65 !important;
  margin-top: 20px !important;
}

/* FAQ */
.faq-list {
  max-width: 760px;
  margin: 0 auto;
  display: grid;
  gap: 16px;
}

.faq-item {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 20px 24px;
}

.faq-item summary {
  font-weight: 600;
  cursor: pointer;
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary::after {
  content: "+";
  font-size: 1.25rem;
  color: var(--primary);
}

.faq-item[open] summary::after {
  content: "−";
}

.faq-item p {
  margin: 14px 0 0;
  color: var(--text-muted);
  font-size: 0.9375rem;
}

/* Footer */
.site-footer {
  background: #031733;
  color: rgba(255, 255, 255, 0.75);
  padding: 64px 0 32px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 48px;
  margin-bottom: 48px;
}

.footer-brand img {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  margin-bottom: 16px;
}

.footer-brand strong {
  display: block;
  color: var(--text-inverse);
  margin-bottom: 6px;
}

.footer-brand p {
  margin: 0;
  font-size: 0.9375rem;
}

.footer-links h4 {
  color: var(--text-inverse);
  font-size: 0.9375rem;
  margin: 0 0 16px;
}

.footer-links a {
  display: block;
  color: rgba(255, 255, 255, 0.75);
  margin-bottom: 10px;
  font-size: 0.9375rem;
  transition: color 0.2s;
}

.footer-links a:hover {
  color: var(--text-inverse);
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding-top: 24px;
  text-align: center;
  font-size: 0.8125rem;
}

.footer-bottom p {
  margin: 4px 0;
}

.footer-bottom .icp a {
  color: rgba(255, 255, 255, 0.55);
  transition: color 0.2s;
}

.footer-bottom .icp a:hover {
  color: rgba(255, 255, 255, 0.85);
}

/* Responsive */
@media (max-width: 900px) {
  .hero-grid,
  .security-grid {
    grid-template-columns: 1fr;
  }

  .features-grid,
  .backup-grid,
  .tech-grid {
    grid-template-columns: 1fr 1fr;
  }

  .hero h1 {
    font-size: 2.5rem;
  }

  .phone-frame {
    transform: none;
  }
}

@media (max-width: 640px) {
  .section {
    padding: 64px 0;
  }

  .section-title {
    font-size: 1.75rem;
  }

  .features-grid,
  .backup-grid,
  .tech-grid {
    grid-template-columns: 1fr;
  }

  .hero {
    padding-top: calc(var(--header-h) + 48px);
  }

  .hero h1 {
    font-size: 2rem;
  }

  .hero-actions {
    flex-direction: column;
  }

  .nav-links {
    position: fixed;
    inset: var(--header-h) 0 auto 0;
    flex-direction: column;
    background: rgba(255, 255, 255, 0.96);
    backdrop-filter: blur(16px);
    padding: 24px;
    gap: 16px;
    border-bottom: 1px solid var(--border);
    transform: translateY(-150%);
    transition: transform 0.25s ease;
  }

  .nav-links.open {
    transform: translateY(0);
  }

  .nav-toggle {
    display: flex;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 32px;
  }
}