:root {
  --brand: #df1f12;
  --brand-dark: #b8180f;
  --ink: #171717;
  --muted: #646a73;
  --line: #e6e8eb;
  --surface: #ffffff;
  --surface-soft: #f5f7f9;
  --surface-warm: #fff3ed;
  --success: #167a52;
  --content: 1180px;
  --radius: 8px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--surface);
  font-family: "Microsoft YaHei", "PingFang SC", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.7;
  letter-spacing: 0;
}

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

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

button,
a {
  -webkit-tap-highlight-color: transparent;
}

.container {
  width: min(calc(100% - 40px), var(--content));
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  border-bottom: 1px solid rgba(230, 232, 235, 0.9);
  background: rgba(255, 255, 255, 0.96);
  backdrop-filter: blur(12px);
}

.header-inner {
  display: flex;
  min-height: 68px;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  font-size: 18px;
  font-weight: 700;
}

.brand img {
  width: 38px;
  height: 38px;
  border-radius: 8px;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 30px;
  color: #454a52;
  font-size: 14px;
}

.site-nav a:hover,
.site-nav a:focus-visible {
  color: var(--brand);
}

.menu-button {
  display: none;
  width: 42px;
  height: 42px;
  padding: 0;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: #fff;
  color: var(--ink);
  font-size: 22px;
  cursor: pointer;
}

.button {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  justify-content: center;
  padding: 0 22px;
  border: 1px solid var(--brand);
  border-radius: 6px;
  background: var(--brand);
  color: #fff;
  font-size: 15px;
  font-weight: 700;
  cursor: pointer;
  transition: background 160ms ease, border-color 160ms ease, transform 160ms ease;
}

.button:hover,
.button:focus-visible {
  border-color: var(--brand-dark);
  background: var(--brand-dark);
  transform: translateY(-1px);
}

.button.secondary {
  background: #fff;
  color: var(--brand);
}

.button.secondary:hover,
.button.secondary:focus-visible {
  background: var(--surface-warm);
}

.button.is-disabled {
  border-color: #b7bbc2;
  background: #b7bbc2;
  color: #fff;
  cursor: not-allowed;
  transform: none;
}

.hero {
  position: relative;
  min-height: 700px;
  overflow: hidden;
  border-bottom: 1px solid var(--line);
  background: #f7f8fa;
}

.hero::before {
  position: absolute;
  inset: 0 auto 0 0;
  width: 10px;
  background: var(--brand);
  content: "";
}

.hero-inner {
  position: relative;
  display: flex;
  min-height: 700px;
  align-items: center;
  padding: 72px 0 92px;
}

.hero-copy {
  position: relative;
  z-index: 2;
  width: min(600px, 58%);
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  margin-bottom: 22px;
  color: var(--brand);
  font-size: 14px;
  font-weight: 700;
}

.eyebrow::before {
  width: 26px;
  height: 3px;
  background: var(--brand);
  content: "";
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 22px;
  font-size: clamp(46px, 6vw, 76px);
  line-height: 1.08;
  letter-spacing: 0;
}

.hero-lead {
  max-width: 560px;
  margin-bottom: 30px;
  color: #4b5058;
  font-size: 19px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 34px;
}

.meta-list {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 24px;
  color: var(--muted);
  font-size: 13px;
}

.meta-list span {
  position: relative;
  padding-left: 14px;
}

.meta-list span::before {
  position: absolute;
  top: 0.7em;
  left: 0;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--success);
  content: "";
}

.hero-visual {
  position: absolute;
  top: 54px;
  right: 1%;
  width: min(390px, 36vw);
  height: 760px;
  overflow: hidden;
  border: 10px solid #181818;
  border-bottom: 0;
  border-radius: 34px 34px 0 0;
  background: #fff;
  box-shadow: 0 28px 70px rgba(23, 23, 23, 0.18);
}

.hero-visual img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: top center;
}

.section {
  padding: 88px 0;
}

.section.soft {
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: var(--surface-soft);
}

.section-heading {
  display: grid;
  grid-template-columns: minmax(0, 0.85fr) minmax(320px, 1.15fr);
  gap: 64px;
  align-items: end;
  margin-bottom: 54px;
}

.section-heading h2 {
  margin-bottom: 0;
  font-size: 36px;
  line-height: 1.25;
}

.section-heading p {
  margin-bottom: 0;
  color: var(--muted);
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  border-top: 1px solid var(--line);
}

.feature-item {
  min-height: 228px;
  padding: 30px 24px 28px 0;
  border-bottom: 1px solid var(--line);
}

.feature-item + .feature-item {
  padding-left: 24px;
  border-left: 1px solid var(--line);
}

.feature-index {
  display: block;
  margin-bottom: 30px;
  color: var(--brand);
  font-size: 13px;
  font-weight: 700;
}

.feature-item h3 {
  margin-bottom: 10px;
  font-size: 20px;
}

.feature-item p {
  margin-bottom: 0;
  color: var(--muted);
  font-size: 14px;
}

.workflow {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 18px;
}

.workflow-step {
  position: relative;
  padding: 28px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
}

.workflow-step strong {
  display: block;
  margin-bottom: 10px;
  color: var(--brand);
  font-size: 14px;
}

.workflow-step h3 {
  margin-bottom: 8px;
  font-size: 18px;
}

.workflow-step p {
  margin-bottom: 0;
  color: var(--muted);
  font-size: 14px;
}

.screens-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 28px;
  align-items: start;
}

.screen-card {
  margin: 0;
}

.phone-shot {
  position: relative;
  aspect-ratio: 9 / 16;
  overflow: hidden;
  border: 9px solid #151515;
  border-radius: 30px;
  background: #fff;
  box-shadow: 0 18px 44px rgba(23, 23, 23, 0.12);
}

.phone-shot img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: top center;
}

.screen-card figcaption {
  padding: 18px 4px 0;
}

.screen-card strong {
  display: block;
  margin-bottom: 3px;
  font-size: 17px;
}

.screen-card span {
  color: var(--muted);
  font-size: 14px;
}

.security-band {
  position: relative;
  overflow: hidden;
  padding: 70px 0;
  background: #202124;
  color: #fff;
}

.security-band::after {
  position: absolute;
  top: 0;
  right: 0;
  width: 28%;
  height: 100%;
  background: var(--brand);
  content: "";
}

.security-content {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: 72px;
}

.security-content h2 {
  margin-bottom: 12px;
  font-size: 34px;
}

.security-content > div > p {
  color: #c8cbd0;
}

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

.security-point {
  min-height: 116px;
  padding: 20px;
  border: 1px solid #4a4d52;
  border-radius: var(--radius);
  background: #292b2f;
}

.security-point strong {
  display: block;
  margin-bottom: 6px;
}

.security-point span {
  color: #c8cbd0;
  font-size: 13px;
}

.download-panel {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 40px;
  align-items: center;
  padding: 42px;
  border: 1px solid var(--line);
  border-left: 5px solid var(--brand);
  border-radius: var(--radius);
  background: #fff;
}

.download-panel h2 {
  margin-bottom: 8px;
  font-size: 30px;
}

.download-panel p {
  max-width: 720px;
  margin-bottom: 0;
  color: var(--muted);
}

.download-note {
  transition: background 160ms ease, color 160ms ease;
}

.download-note.is-highlighted {
  background: var(--surface-warm);
  color: var(--brand-dark);
}

.site-footer {
  border-top: 1px solid var(--line);
  background: #fff;
}

.footer-main {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  padding: 58px 0 38px;
}

.footer-main h2 {
  margin-bottom: 14px;
  font-size: 22px;
}

.footer-main p,
.footer-main address {
  margin-bottom: 6px;
  color: var(--muted);
  font-size: 14px;
  font-style: normal;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  align-content: start;
  justify-content: flex-end;
  gap: 12px 26px;
  color: #454a52;
  font-size: 14px;
}

.footer-links a:hover,
.footer-links a:focus-visible {
  color: var(--brand);
}

.footer-bottom {
  display: flex;
  min-height: 62px;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  border-top: 1px solid var(--line);
  color: #7a7f87;
  font-size: 12px;
}

.legal-hero {
  padding: 76px 0 54px;
  border-bottom: 1px solid var(--line);
  background: var(--surface-soft);
}

.legal-hero h1 {
  margin-bottom: 14px;
  font-size: 44px;
}

.legal-hero p {
  margin-bottom: 0;
  color: var(--muted);
}

.legal-layout {
  display: grid;
  grid-template-columns: 230px minmax(0, 760px);
  gap: 60px;
  padding: 62px 0 90px;
  justify-content: center;
}

.legal-aside {
  position: sticky;
  top: 98px;
  align-self: start;
  padding: 18px 0;
  border-top: 2px solid var(--brand);
  border-bottom: 1px solid var(--line);
}

.legal-aside a {
  display: block;
  padding: 8px 0;
  color: var(--muted);
  font-size: 13px;
}

.legal-aside a:hover,
.legal-aside a:focus-visible {
  color: var(--brand);
}

.legal-content section {
  scroll-margin-top: 100px;
  margin-bottom: 42px;
}

.legal-content h2 {
  margin-bottom: 14px;
  font-size: 24px;
}

.legal-content h3 {
  margin: 22px 0 8px;
  font-size: 17px;
}

.legal-content p,
.legal-content li {
  color: #4e535b;
  font-size: 15px;
}

.legal-content ul,
.legal-content ol {
  margin: 10px 0 0;
  padding-left: 22px;
}

.legal-callout {
  padding: 20px 22px;
  border: 1px solid #f0c8bc;
  border-radius: var(--radius);
  background: var(--surface-warm);
  color: #67271d;
}

.download-page-panel {
  display: grid;
  grid-template-columns: 88px 1fr;
  gap: 24px;
  align-items: center;
  margin: 36px 0;
  padding: 28px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
}

.download-page-panel img {
  width: 88px;
  height: 88px;
  border-radius: 16px;
}

.download-meta {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px 24px;
  margin: 22px 0;
}

.download-meta div {
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line);
}

.download-meta small,
.download-meta strong {
  display: block;
}

.download-meta small {
  margin-bottom: 3px;
  color: var(--muted);
}

@media (max-width: 900px) {
  .site-nav {
    position: absolute;
    top: 68px;
    right: 20px;
    left: 20px;
    display: none;
    padding: 18px;
    border: 1px solid var(--line);
    border-radius: var(--radius);
    background: #fff;
    box-shadow: 0 18px 50px rgba(23, 23, 23, 0.13);
  }

  .site-nav.is-open {
    display: grid;
    gap: 16px;
  }

  .menu-button {
    display: inline-grid;
    place-items: center;
  }

  .hero,
  .hero-inner {
    min-height: 650px;
  }

  .hero-copy {
    width: 64%;
  }

  .hero-visual {
    right: -10%;
    width: 42vw;
    opacity: 0.8;
  }

  .feature-grid,
  .workflow {
    grid-template-columns: repeat(2, 1fr);
  }

  .feature-item:nth-child(3) {
    padding-left: 0;
    border-left: 0;
  }

  .security-content {
    grid-template-columns: 1fr;
  }

  .security-band::after {
    display: none;
  }
}

@media (max-width: 640px) {
  .container {
    width: min(calc(100% - 28px), var(--content));
  }

  .header-inner {
    min-height: 62px;
  }

  .site-nav {
    top: 62px;
    right: 14px;
    left: 14px;
  }

  .hero {
    min-height: 720px;
  }

  .hero-inner {
    min-height: 720px;
    align-items: flex-start;
    padding-top: 62px;
  }

  .hero-copy {
    width: 100%;
  }

  h1 {
    font-size: 46px;
  }

  .hero-lead {
    max-width: 94%;
    font-size: 17px;
  }

  .hero-visual {
    top: 380px;
    right: -22px;
    width: 215px;
    height: 470px;
    border-width: 7px;
    border-radius: 24px 24px 0 0;
    opacity: 1;
  }

  .meta-list {
    width: 58%;
    display: grid;
    gap: 6px;
  }

  .section {
    padding: 64px 0;
  }

  .section-heading {
    grid-template-columns: 1fr;
    gap: 18px;
    margin-bottom: 38px;
  }

  .section-heading h2 {
    font-size: 30px;
  }

  .feature-grid,
  .workflow,
  .screens-grid,
  .security-points {
    grid-template-columns: 1fr;
  }

  .feature-item,
  .feature-item + .feature-item {
    min-height: 0;
    padding: 24px 0;
    border-left: 0;
  }

  .feature-index {
    margin-bottom: 18px;
  }

  .screens-grid {
    gap: 42px;
  }

  .phone-shot {
    width: min(84vw, 340px);
    margin: 0 auto;
  }

  .security-content {
    gap: 34px;
  }

  .download-panel {
    grid-template-columns: 1fr;
    padding: 28px 22px;
  }

  .download-panel .button {
    width: 100%;
  }

  .footer-main {
    grid-template-columns: 1fr;
    gap: 28px;
    padding-top: 42px;
  }

  .footer-links {
    justify-content: flex-start;
  }

  .footer-bottom {
    align-items: flex-start;
    flex-direction: column;
    justify-content: center;
    padding: 16px 0;
  }

  .legal-hero {
    padding: 52px 0 38px;
  }

  .legal-hero h1 {
    font-size: 34px;
  }

  .legal-layout {
    grid-template-columns: 1fr;
    gap: 30px;
    padding-top: 36px;
  }

  .legal-aside {
    position: static;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
  }

  .download-page-panel {
    grid-template-columns: 66px 1fr;
    padding: 20px;
  }

  .download-page-panel img {
    width: 66px;
    height: 66px;
  }

  .download-meta {
    grid-template-columns: 1fr;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
  }
}