:root {
  --ink: #10233f;
  --muted: #5b708d;
  --paper: #f3f8ff;
  --surface: #ffffff;
  --line: #d7e6f7;
  --brand: #1769e0;
  --brand-deep: #0b3475;
  --accent: #2f9cff;
  --good: #1769e0;
  --danger: #c84c4c;
  --shadow: 0 18px 44px rgba(18, 72, 134, .12);
  --radius: 8px;
  color-scheme: light;
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: "Microsoft YaHei", "PingFang SC", "Noto Sans SC", Arial, sans-serif;
  color: var(--ink);
  background: var(--paper);
  line-height: 1.7;
}

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

a {
  color: inherit;
  text-decoration: none;
}

.skip-link {
  position: absolute;
  left: 16px;
  top: -48px;
  padding: 10px 14px;
  background: var(--ink);
  color: #ffffff;
  z-index: 20;
}

.skip-link:focus { top: 12px; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(255, 255, 255, .94);
  border-bottom: 1px solid rgba(215, 230, 247, .9);
  backdrop-filter: blur(12px);
}

.nav {
  width: min(1180px, calc(100% - 40px));
  margin: 0 auto;
  min-height: 74px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 22px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  font-weight: 900;
  font-size: 21px;
}

.brand-mark {
  width: 46px;
  height: 46px;
  flex: 0 0 46px;
  border-radius: 7px;
  object-fit: cover;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 24px;
  font-size: 15px;
  color: #314b6d;
}

.nav-links a[aria-current="page"],
.nav-links a:hover {
  color: var(--brand);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.menu-toggle {
  display: none;
  width: 42px;
  height: 42px;
  border: 1px solid var(--line);
  background: var(--surface);
  border-radius: 8px;
  color: var(--ink);
  font-size: 24px;
}

.button,
button.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  min-height: 46px;
  padding: 0 18px;
  border: 1px solid transparent;
  border-radius: 8px;
  background: var(--brand);
  color: #ffffff;
  font-weight: 800;
  cursor: pointer;
  transition: transform .18s ease, box-shadow .18s ease, background .18s ease;
}

.button:hover {
  transform: translateY(-1px);
  box-shadow: 0 10px 24px rgba(23, 105, 224, .24);
  background: #0f58c7;
}

.button.secondary {
  background: transparent;
  color: var(--brand-deep);
  border-color: #9fc3ee;
}

.button.secondary:hover {
  box-shadow: none;
  background: #eaf3ff;
}

.button.accent {
  background: var(--accent);
  color: #ffffff;
}

.hero {
  min-height: clamp(620px, calc(100vh - 140px), 820px);
  display: grid;
  align-items: center;
  background: #eaf3ff url("../img/easybcd-interface.svg") right 4vw center / min(680px, 52vw) auto no-repeat;
  border-bottom: 1px solid var(--line);
}

.hero-inner,
.section-inner {
  width: min(1180px, calc(100% - 40px));
  margin: 0 auto;
}

.hero-copy {
  max-width: 500px;
  padding: 74px 0 92px;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin: 0 0 18px;
  color: var(--brand-deep);
  font-weight: 900;
  letter-spacing: .04em;
  text-transform: uppercase;
  font-size: 13px;
}

.eyebrow::before {
  content: "";
  width: 28px;
  height: 2px;
  background: var(--accent);
}

h1,
h2,
h3 {
  margin: 0;
  line-height: 1.16;
  letter-spacing: 0;
}

h1 {
  font-size: clamp(42px, 6vw, 82px);
  max-width: 10ch;
}

.hero-subtitle {
  max-width: 58ch;
  margin: 26px 0 0;
  font-size: 19px;
  color: #365170;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 34px;
}

.trust-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 34px;
  color: #314b6d;
}

.trust-row span {
  border: 1px solid #c8ddf5;
  background: rgba(255, 255, 255, .86);
  border-radius: 999px;
  padding: 8px 12px;
  font-size: 14px;
  font-weight: 700;
}

.section {
  padding: 82px 0;
  background: #ffffff;
  border-bottom: 1px solid var(--line);
}

.section.alt {
  background: #eaf3ff;
}

.section.dark {
  background: #eaf3ff;
  color: var(--ink);
}

.section-head {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 26px;
  margin-bottom: 36px;
}

.section-head h2,
.page-title h1 {
  font-size: clamp(31px, 4vw, 52px);
}

.section-head p,
.page-title p {
  max-width: 62ch;
  margin: 14px 0 0;
  color: var(--muted);
}

.dark .section-head p,
.dark .muted {
  color: var(--muted);
}

.grid {
  display: grid;
  gap: 18px;
}

.grid.three { grid-template-columns: repeat(3, 1fr); }
.grid.two { grid-template-columns: repeat(2, 1fr); }
.grid.four { grid-template-columns: repeat(4, 1fr); }

.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 26px;
  min-width: 0;
}

.card h3 {
  font-size: 22px;
  margin-bottom: 10px;
}

.card p {
  margin: 0;
  color: var(--muted);
}

.icon {
  width: 42px;
  height: 42px;
  display: grid;
  place-items: center;
  margin-bottom: 18px;
  border-radius: 8px;
  background: #e0efff;
  color: var(--brand-deep);
  font-size: 22px;
}

.feature-band {
  display: grid;
  grid-template-columns: .9fr 1.1fr;
  gap: 40px;
  align-items: center;
}

.screen-frame {
  border-radius: 8px;
  overflow: hidden;
  border: 1px solid #bdd7f5;
  background: #ffffff;
  box-shadow: var(--shadow);
}

.scenario {
  display: grid;
  grid-template-columns: 96px 1fr;
  gap: 18px;
  align-items: start;
  padding: 24px 0;
  border-top: 1px solid rgba(215, 230, 247, .9);
}

.scenario strong {
  display: grid;
  place-items: center;
  width: 72px;
  height: 72px;
  border-radius: 8px;
  background: var(--brand-deep);
  color: #ffffff;
  font-size: 24px;
}

.quote {
  position: relative;
  padding-top: 34px;
}

.quote::before {
  content: "“";
  position: absolute;
  top: -12px;
  left: 24px;
  color: var(--accent);
  font-size: 86px;
  line-height: 1;
  font-family: Georgia, serif;
}

.quote p {
  color: var(--ink);
  font-size: 17px;
}

.quote cite {
  display: block;
  margin-top: 18px;
  color: var(--muted);
  font-style: normal;
  font-weight: 800;
}

.page-hero {
  padding: 78px 0 56px;
  background: #eaf3ff;
  border-bottom: 1px solid var(--line);
}

.breadcrumb {
  font-size: 14px;
  color: var(--muted);
  margin-bottom: 18px;
}

.breadcrumb a {
  color: var(--brand);
  font-weight: 800;
}

.page-title {
  max-width: 820px;
}

.split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 34px;
  align-items: start;
}

.list {
  margin: 18px 0 0;
  padding: 0;
  list-style: none;
}

.list li {
  position: relative;
  padding: 10px 0 10px 30px;
  border-bottom: 1px solid rgba(215, 230, 247, .78);
}

.list li::before {
  content: "✓";
  position: absolute;
  left: 0;
  top: 10px;
  color: var(--good);
  font-weight: 900;
}

.timeline {
  counter-reset: step;
}

.timeline article {
  position: relative;
  padding: 0 0 30px 58px;
  border-left: 1px solid #bed8f5;
}

.timeline article::before {
  counter-increment: step;
  content: counter(step);
  position: absolute;
  left: -20px;
  top: 0;
  width: 39px;
  height: 39px;
  display: grid;
  place-items: center;
  border-radius: 8px;
  background: var(--brand);
  color: #ffffff;
  font-weight: 900;
}

.download-panel {
  display: grid;
  grid-template-columns: 1.1fr .9fr;
  gap: 26px;
  align-items: stretch;
}

.download-box {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 30px;
  box-shadow: var(--shadow);
}

.download-meta {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
  margin: 24px 0;
}

.download-meta span {
  padding: 12px;
  border-radius: 8px;
  background: #eaf3ff;
  color: #314b6d;
  font-weight: 800;
}

.warning {
  border: 1px solid #9fc3ee;
  background: #edf6ff;
  color: #173b70;
  border-radius: 8px;
  padding: 18px;
}

.footer {
  background: #0b2f68;
  color: #dbe8eb;
  padding: 46px 0 24px;
}

.footer-grid {
  width: min(1180px, calc(100% - 40px));
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1.2fr repeat(2, 1fr);
  gap: 28px;
}

.footer h2,
.footer h3 {
  color: #ffffff;
}

.footer a {
  display: block;
  color: #c7d7db;
  margin-top: 8px;
}

.copyright {
  width: min(1180px, calc(100% - 40px));
  margin: 34px auto 0;
  padding-top: 20px;
  border-top: 1px solid rgba(255,255,255,.14);
  color: #a9bdc3;
  font-size: 14px;
}

.modal {
  position: fixed;
  inset: 0;
  z-index: 30;
  display: none;
  align-items: center;
  justify-content: center;
  padding: 20px;
  background: rgba(12, 25, 31, .68);
}

.modal.is-open { display: flex; }

.modal-dialog {
  width: min(760px, 100%);
  max-height: calc(100vh - 40px);
  overflow: auto;
  background: var(--surface);
  border-radius: 8px;
  box-shadow: 0 26px 70px rgba(0, 0, 0, .32);
}

.modal-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding: 24px 26px;
  border-bottom: 1px solid var(--line);
}

.modal-close {
  width: 42px;
  height: 42px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #ffffff;
  font-size: 28px;
  cursor: pointer;
}

.modal-body {
  padding: 26px;
}

.qr-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 18px;
}

.qr-card {
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 18px;
  background: #ffffff;
  text-align: center;
}

.qr-card img {
  width: 190px;
  height: 190px;
  margin: 0 auto 14px;
  border: 8px solid #e6f1ff;
}

.source-note {
  margin-top: 18px;
  color: var(--muted);
  font-size: 14px;
}

@media (max-width: 900px) {
  .menu-toggle { display: grid; place-items: center; }
  .nav { flex-wrap: wrap; padding: 12px 0; }
  .nav-links {
    display: none;
    width: 100%;
    flex-direction: column;
    align-items: flex-start;
    padding: 12px 0;
  }
  .nav-links.is-open { display: flex; }
  .nav-actions { margin-left: auto; }
  .hero {
    min-height: auto;
    background: #eaf3ff url("../img/easybcd-interface.svg") center bottom 18px / 92vw auto no-repeat;
  }
  .hero-copy { padding-bottom: 56vw; }
  .grid.three,
  .grid.two,
  .grid.four,
  .feature-band,
  .split,
  .download-panel,
  .footer-grid {
    grid-template-columns: 1fr;
  }
  .section-head { display: block; }
}

@media (max-width: 560px) {
  .nav,
  .hero-inner,
  .section-inner,
  .footer-grid,
  .copyright {
    width: min(100% - 28px, 1180px);
  }
  h1 { font-size: 40px; }
  .section { padding: 58px 0; }
  .nav-actions .button { display: none; }
  .hero-actions .button { width: 100%; }
  .scenario { grid-template-columns: 1fr; }
  .download-meta,
  .qr-grid { grid-template-columns: 1fr; }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
    scroll-behavior: auto !important;
    transition-duration: .01ms !important;
  }
}