:root {
  --ink: #152027;
  --muted: #5e6a70;
  --paper: #f6f1e8;
  --paper-strong: #fffaf1;
  --line: rgba(21, 32, 39, 0.13);
  --steel: #8b949e;
  --blue: #145c73;
  --blue-strong: #0b3d52;
  --orange: #d8752e;
  --yellow: #f2c265;
  --green: #4c7b5a;
  --shadow: 0 24px 70px rgba(21, 32, 39, 0.18);
  --radius: 28px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  font-family: "Aptos", "Bahnschrift", "Microsoft YaHei UI", "Noto Sans SC", sans-serif;
  background:
    radial-gradient(circle at 15% 10%, rgba(242, 194, 101, 0.35), transparent 30rem),
    radial-gradient(circle at 92% 4%, rgba(20, 92, 115, 0.16), transparent 28rem),
    linear-gradient(135deg, #f8f3eb 0%, #ede4d5 45%, #f7efe2 100%);
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  width: min(1180px, calc(100% - 32px));
  margin: 16px auto 0;
  padding: 12px 14px;
  border: 1px solid rgba(255, 255, 255, 0.5);
  border-radius: 999px;
  background: rgba(255, 250, 241, 0.78);
  box-shadow: 0 14px 45px rgba(21, 32, 39, 0.1);
  backdrop-filter: blur(18px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-width: 220px;
}

.brand img {
  width: 42px;
  height: 42px;
}

.brand strong,
.brand small {
  display: block;
  line-height: 1.05;
}

.brand strong {
  font-size: 18px;
  letter-spacing: 0.08em;
}

.brand small {
  margin-top: 3px;
  color: var(--muted);
  font-size: 11px;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 4px;
}

.site-nav a {
  padding: 10px 13px;
  border-radius: 999px;
  color: #314047;
  font-size: 14px;
}

.site-nav a:hover {
  background: rgba(20, 92, 115, 0.1);
  color: var(--blue-strong);
}

.site-nav .lang-switch {
  border: 1px solid rgba(20, 92, 115, 0.22);
  color: var(--blue-strong);
  font-weight: 800;
}

.nav-toggle {
  display: none;
  border: 0;
  border-radius: 999px;
  padding: 10px 14px;
  color: #fff;
  background: var(--blue-strong);
}

.section-shell {
  width: min(1180px, calc(100% - 32px));
  margin: 0 auto;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(380px, 0.95fr);
  gap: 46px;
  align-items: center;
  min-height: calc(100vh - 72px);
  padding: 72px 0 64px;
}

.hero-copy {
  animation: rise 0.75s ease both;
}

.eyebrow {
  margin: 0 0 14px;
  color: var(--orange);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.18em;
}

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

h1 {
  max-width: 760px;
  margin-bottom: 24px;
  font-family: "Aptos Display", "Microsoft YaHei UI", sans-serif;
  font-size: clamp(42px, 6vw, 82px);
  line-height: 0.95;
  letter-spacing: -0.055em;
}

h2 {
  margin-bottom: 16px;
  font-size: clamp(30px, 4vw, 52px);
  line-height: 1.04;
  letter-spacing: -0.04em;
}

h3 {
  margin-bottom: 12px;
  font-size: 22px;
}

.hero-lead,
.section-heading p,
.license-card p,

.video-card + .video-card {
  margin-top: 24px;
}

.video-card p {
  color: var(--muted);
  font-size: 18px;
  line-height: 1.75;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 30px;
}

.hero-actions.centered {
  justify-content: center;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 0 22px;
  border: 1px solid rgba(21, 32, 39, 0.14);
  border-radius: 999px;
  font-weight: 800;
  transition: transform 0.18s ease, box-shadow 0.18s ease, background 0.18s ease;
}

.button:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 32px rgba(21, 32, 39, 0.15);
}

.button.primary {
  color: #fff;
  border-color: var(--blue-strong);
  background: linear-gradient(135deg, var(--blue-strong), var(--blue));
}

.button.ghost {
  background: rgba(255, 255, 255, 0.42);
}

.button.dark {
  color: #fff;
  background: var(--ink);
}

.button.dark-text {
  color: var(--ink);
}

.button.light {
  color: #fff;
  border-color: rgba(255, 255, 255, 0.28);
  background: rgba(255, 255, 255, 0.08);
}

.hero-metrics {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  max-width: 620px;
  margin: 42px 0 0;
}

.hero-metrics div {
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 22px;
  background: rgba(255, 250, 241, 0.55);
}

.hero-metrics dt {
  font-size: 30px;
  font-weight: 900;
}

.hero-metrics dd {
  margin: 4px 0 0;
  color: var(--muted);
}

.hero-panel {
  position: relative;
  overflow: hidden;
  border: 1px solid rgba(255, 255, 255, 0.55);
  border-radius: 36px;
  background:
    linear-gradient(135deg, rgba(20, 92, 115, 0.92), rgba(21, 32, 39, 0.96)),
    radial-gradient(circle at 50% 20%, rgba(242, 194, 101, 0.35), transparent 20rem);
  box-shadow: var(--shadow);
  animation: rise 0.75s 0.1s ease both;
}

.hero-image-panel {
  margin: 0;
  padding: 14px;
}

.hero-image {
  display: block;
  width: 100%;
  height: auto;
  border-radius: 26px;
  background: rgba(255, 255, 255, 0.72);
  box-shadow: 0 18px 44px rgba(6, 31, 43, 0.24);
}

.panel-toolbar {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 18px 20px;
  color: rgba(255, 255, 255, 0.74);
}

.panel-toolbar span {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--yellow);
}

.panel-toolbar span:nth-child(2) {
  background: #ed9b62;
}

.panel-toolbar span:nth-child(3) {
  background: #7eb28d;
}

.panel-toolbar b {
  margin-left: auto;
  font-size: 12px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.assembly-card {
  position: relative;
  height: 430px;
  margin: 28px;
  border-radius: 30px;
  background:
    radial-gradient(circle at 48% 35%, rgba(255, 255, 255, 0.14), transparent 18rem),
    linear-gradient(145deg, rgba(255, 255, 255, 0.12), rgba(255, 255, 255, 0.035));
}

.part-stack {
  position: absolute;
  inset: 64px 88px 58px;
}

.plate {
  position: absolute;
  left: 12%;
  right: 12%;
  height: 74px;
  border: 1px solid rgba(255, 255, 255, 0.26);
  border-radius: 20px;
  background: linear-gradient(135deg, #a9b0b8, #6f7881);
  box-shadow: inset 0 18px 34px rgba(255, 255, 255, 0.16), inset 0 -20px 28px rgba(0, 0, 0, 0.2);
  transform: skewX(-12deg);
}

.plate.top {
  top: 40px;
}

.plate.middle {
  top: 150px;
  left: 4%;
  right: 4%;
}

.plate.bottom {
  top: 260px;
}

.fastener-line {
  position: absolute;
  left: 50%;
  top: 18px;
  width: 24px;
  height: 340px;
  border-radius: 999px;
  background: linear-gradient(90deg, #d8dce3, #7b828c 48%, #343941);
  transform: translateX(-50%);
}

.fastener-line::before {
  content: "";
  position: absolute;
  left: 50%;
  top: -34px;
  width: 120px;
  height: 52px;
  border-radius: 50%;
  background: linear-gradient(160deg, #c9ced6, #555b64);
  transform: translateX(-50%);
}

.callout {
  position: absolute;
  padding: 10px 13px;
  border: 1px solid rgba(255, 255, 255, 0.24);
  border-radius: 999px;
  color: #fff;
  font-size: 13px;
  background: rgba(21, 32, 39, 0.42);
}

.c1 {
  left: 24px;
  top: 34px;
}

.c2 {
  right: 18px;
  top: 176px;
}

.c3 {
  left: 42px;
  bottom: 28px;
}

.panel-footer {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  padding: 0 28px 28px;
}

.panel-footer span {
  padding: 12px;
  border-radius: 16px;
  color: rgba(255, 255, 255, 0.84);
  font-size: 12px;
  text-align: center;
  background: rgba(255, 255, 255, 0.09);
}

.problem,
.features,
.video-section,
.download,
.purchase,
.contact,
.license,
.faq,
.final-cta {
  padding: 74px 0;
}

.section-heading {
  max-width: 850px;
  margin-bottom: 34px;
}

.section-heading.narrow {
  max-width: 760px;
  margin-left: auto;
  margin-right: auto;
  text-align: center;
}

.problem-grid,
.download-grid,
.service-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}

.problem-grid article,
.download-card,
.service-grid article,
.feature-card,
.video-card,
.license-card,
.faq details {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(255, 250, 241, 0.62);
  box-shadow: 0 18px 45px rgba(21, 32, 39, 0.07);
}

.problem-grid article {
  padding: 26px;
}

.problem-grid strong {
  display: block;
  margin-bottom: 10px;
  font-size: 28px;
}

.problem-grid p,
.feature-card p,
.download-card p,
.service-grid p,
.faq p {
  color: var(--muted);
  line-height: 1.72;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}

.feature-card {
  position: relative;
  min-height: 260px;
  padding: 28px;
  overflow: hidden;
}

.feature-card.large {
  grid-column: span 2;
  background: linear-gradient(135deg, rgba(20, 92, 115, 0.95), rgba(11, 61, 82, 0.95));
  color: #fff;
}

.feature-card.large p {
  color: rgba(255, 255, 255, 0.78);
}

.feature-index {
  display: inline-flex;
  margin-bottom: 42px;
  color: var(--orange);
  font-weight: 900;
  letter-spacing: 0.12em;
}

.feature-card.large .feature-index {
  color: var(--yellow);
}

.video-card {
  display: grid;
  grid-template-columns: minmax(360px, 1.08fr) minmax(0, 0.92fr);
  gap: 32px;
  align-items: center;
  min-height: 330px;
  padding: 38px;
  background:
    linear-gradient(135deg, rgba(21, 32, 39, 0.95), rgba(20, 92, 115, 0.85)),
    radial-gradient(circle at 80% 10%, rgba(242, 194, 101, 0.25), transparent 18rem);
  color: #fff;
}

.video-embed {
  position: relative;
  overflow: hidden;
  border: 1px solid rgba(255, 255, 255, 0.22);
  border-radius: 24px;
  background: rgba(0, 0, 0, 0.28);
  box-shadow: 0 22px 60px rgba(0, 0, 0, 0.25);
  aspect-ratio: 16 / 9;
}

.video-embed iframe {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

.video-card p {
  color: rgba(255, 255, 255, 0.72);
}

.video-kicker {
  color: var(--yellow) !important;
  font-weight: 800;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.video-actions {
  margin-top: 22px;
}

.play-ring {
  position: relative;
  width: 190px;
  height: 190px;
  border: 2px solid rgba(255, 255, 255, 0.32);
  border-radius: 50%;
  background: radial-gradient(circle, rgba(255, 255, 255, 0.16), rgba(255, 255, 255, 0.04));
}

.play-ring::after {
  content: "";
  position: absolute;
  left: 76px;
  top: 58px;
  border-top: 36px solid transparent;
  border-bottom: 36px solid transparent;
  border-left: 56px solid var(--yellow);
}

.download-card,
.service-grid article {
  padding: 28px;
}

.service-grid article {
  display: flex;
  flex-direction: column;
}


.service-kicker {
  align-self: flex-start;
  margin-bottom: 16px;
  padding: 7px 11px;
  border-radius: 999px;
  color: var(--blue-strong);
  background: rgba(20, 92, 115, 0.12);
  font-size: 12px;
  font-weight: 900;
}

.download-card.featured {
  background: linear-gradient(135deg, #fffaf1, #f1d8b4);
}

.download-card .button {
  margin-top: 16px;
}

.purchase-actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 14px;
  margin-top: 26px;
}.license-card {
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: 26px;
  align-items: center;
  padding: 34px;
  background: linear-gradient(135deg, rgba(255, 250, 241, 0.8), rgba(223, 234, 230, 0.72));
}

.license-steps {
  display: grid;
  gap: 12px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.license-steps li {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 16px;
  border-radius: 18px;
  background: rgba(255, 255, 255, 0.64);
}

.license-steps span {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  border-radius: 50%;
  color: #fff;
  font-size: 13px;
  font-weight: 900;
  background: var(--blue-strong);
}

.faq-list {
  display: grid;
  gap: 12px;
}

.faq details {
  padding: 20px 24px;
}

.faq summary {
  cursor: pointer;
  font-size: 18px;
  font-weight: 900;
}

.faq p {
  margin: 14px 0 0;
}

.final-cta {
  margin-bottom: 40px;
  padding: 70px 28px;
  border-radius: 38px;
  color: #fff;
  text-align: center;
  background:
    radial-gradient(circle at 15% 20%, rgba(242, 194, 101, 0.35), transparent 22rem),
    linear-gradient(135deg, var(--blue-strong), var(--ink));
  box-shadow: var(--shadow);
}

.final-cta h2 {
  max-width: 820px;
  margin-left: auto;
  margin-right: auto;
}

.site-footer {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  width: min(1180px, calc(100% - 32px));
  margin: 0 auto;
  padding: 30px 0 46px;
  color: var(--muted);
  font-size: 14px;
  text-align: center;
}

.site-footer strong,
.site-footer span {
  display: block;
}

.site-footer strong {
  color: var(--ink);
  letter-spacing: 0.12em;
}

.footer-legal {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  text-align: center;
}

.footer-legal p {
  margin: 0;
}

.footer-legal a:hover {
  color: var(--ink);
}

.beian-links {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 8px 18px;
}

.police-beian {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.police-beian img {
  width: 20px;
  height: 20px;
  object-fit: contain;
  flex: 0 0 auto;
}

@keyframes rise {
  from {
    opacity: 0;
    transform: translateY(18px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 920px) {
  .site-header {
    align-items: flex-start;
    border-radius: 28px;
  }

  .nav-toggle {
    display: inline-flex;
  }

  .site-nav {
    position: absolute;
    left: 14px;
    right: 14px;
    top: 72px;
    display: none;
    flex-direction: column;
    align-items: stretch;
    padding: 12px;
    border-radius: 22px;
    background: var(--paper-strong);
    box-shadow: var(--shadow);
  }

  .site-nav.is-open {
    display: flex;
  }

  .hero,
  .license-card,
  .video-card {
    grid-template-columns: 1fr;
  }

  .hero {
    padding-top: 54px;
  }

  .hero-panel {
    min-height: 500px;
  }

  .hero-image-panel {
    min-height: auto;
  }

.feature-grid,
  .problem-grid,
  .download-grid,
  .service-grid {
    grid-template-columns: 1fr;
  }

  .feature-card.large {
    grid-column: span 1;
  }

  .site-footer {
    flex-direction: column;
  }
}

@media (max-width: 560px) {
  .hero-metrics,
  .panel-footer {
    grid-template-columns: 1fr;
  }

  .hero-panel {
    min-height: 420px;
  }

  .hero-image-panel {
    min-height: auto;
  }

  .assembly-card {
    margin: 16px;
  }

  .part-stack {
    inset: 42px 34px 40px;
  }

  .video-card {
    padding: 26px;
  }

  .play-ring {
    width: 140px;
    height: 140px;
  }

  .play-ring::after {
    left: 58px;
    top: 44px;
    border-top-width: 26px;
    border-bottom-width: 26px;
    border-left-width: 42px;
  }
}