:root {
  /* Primitive palette */
  --p-paper: oklch(0.983 0.002 95);
  --p-photo: oklch(0.965 0.006 90);
  --p-ink: oklch(0.145 0 0);
  --p-muted: oklch(0.43 0.005 80);
  --p-line: oklch(0.9 0.003 90);
  --p-accent: oklch(0.625 0.052 226);
  --p-accent-text: oklch(0.43 0.065 226);

  /* Semantic palette */
  --surface: var(--p-paper);
  --surface-photo: var(--p-photo);
  --text: var(--p-ink);
  --text-muted: var(--p-muted);
  --divider: var(--p-line);
  --accent: var(--p-accent);
  --accent-text: var(--p-accent-text);

  /* Component tokens */
  --page-gutter: 24px;
  --section-space: 104px;
  --radius-image: 20px;
  --ease-out: cubic-bezier(0.22, 1, 0.36, 1);
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; scroll-padding-top: 88px; }
body {
  min-width: 320px;
  min-height: 100dvh;
  overflow-x: hidden;
  color: var(--text);
  background: var(--surface);
  font-family: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans CJK SC", sans-serif;
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
img { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
button { color: inherit; font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
button { cursor: pointer; }
:focus-visible { outline: 3px solid var(--accent-text); outline-offset: 4px; }
::selection { color: var(--text); background: var(--accent); }

.skip-link {
  position: fixed;
  z-index: 20;
  top: 12px;
  left: 12px;
  padding: 10px 16px;
  color: var(--surface);
  background: var(--text);
  transform: translateY(-160%);
  transition: transform 180ms ease-out;
}
.skip-link:focus { transform: translateY(0); }

.container { width: min(100% - (var(--page-gutter) * 2), 1380px); margin-inline: auto; }
.mobile-break { display: none; }
.site-header {
  position: sticky;
  z-index: 10;
  top: 0;
  background: color-mix(in oklab, var(--surface) 92%, transparent);
  border-bottom: 1px solid transparent;
  backdrop-filter: blur(14px);
  transition: border-color 220ms ease-out, background-color 220ms ease-out;
}
.site-header.is-scrolled { border-bottom-color: var(--divider); background: var(--surface); }
.header-inner {
  width: min(100% - (var(--page-gutter) * 2), 1440px);
  min-height: 76px;
  margin-inline: auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}
.brand { min-height: 44px; display: inline-flex; align-items: center; gap: 10px; font-weight: 700; letter-spacing: -0.02em; }
.brand-mark { width: 12px; height: 12px; flex: 0 0 auto; border-radius: 50%; background: var(--accent); }
.main-nav { display: flex; align-items: center; gap: 28px; font-size: 14px; }
.main-nav a { position: relative; min-height: 44px; display: inline-flex; align-items: center; }
.main-nav a::after {
  content: "";
  position: absolute;
  right: 0;
  bottom: 7px;
  left: 0;
  height: 1px;
  background: var(--accent-text);
  transform: scaleX(0);
  transform-origin: right;
  transition: transform 200ms var(--ease-out);
}
.main-nav a:hover::after, .main-nav a:focus-visible::after { transform: scaleX(1); transform-origin: left; }
.header-status { display: none; align-items: center; gap: 8px; font-size: 12px; font-weight: 600; }
.header-status > span { width: 6px; height: 6px; border-radius: 50%; background: var(--accent); }

.hero { padding-block: 40px 72px; display: grid; gap: 48px; }
.hero-copy { display: flex; flex-direction: column; min-width: 0; }
.version-line { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 12px; font-size: 10px; font-weight: 700; letter-spacing: 0.12em; }
.version-tag { padding: 4px 10px; color: var(--text); background: var(--accent); letter-spacing: 0.04em; }
.hero h1 {
  margin-top: 40px;
  font-size: clamp(68px, 19vw, 124px);
  font-weight: 800;
  line-height: 0.9;
  letter-spacing: -0.075em;
}
.hero h1 span { color: var(--accent); }
.hero-intro { margin-top: 40px; max-width: 520px; }
.hero-intro > p:first-child { font-size: 21px; font-weight: 650; line-height: 1.45; letter-spacing: -0.025em; }
.hero-description { margin-top: 16px; color: var(--text-muted); font-size: 16px; line-height: 1.75; }
.primary-link {
  width: fit-content;
  min-height: 48px;
  margin-top: 28px;
  display: inline-flex;
  align-items: center;
  gap: 32px;
  padding: 11px 18px;
  color: var(--surface);
  background: var(--text);
  border: 1px solid var(--text);
  border-radius: 999px;
  font-size: 14px;
  font-weight: 650;
  transition: color 200ms ease-out, background-color 200ms ease-out, transform 200ms var(--ease-out);
}
.primary-link svg, .promo-bottom svg { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-width: 1.5; }
.primary-link:hover { color: var(--text); background: var(--surface); transform: translateY(-2px); }
.primary-link:active { transform: translateY(0); }
.hero-contact { margin-top: 20px; padding-top: 14px; display: flex; flex-wrap: wrap; align-items: center; gap: 2px 16px; border-top: 1px solid var(--divider); font-size: 13px; }
.hero-contact > span { color: var(--text-muted); }
.hero-contact a { min-height: 44px; display: inline-flex; align-items: center; color: var(--accent-text); font-weight: 650; text-decoration: underline; text-decoration-color: var(--divider); text-underline-offset: 4px; overflow-wrap: anywhere; transition: color 180ms ease-out; }
.hero-contact a:hover { color: var(--text); }

/* All four product photographs share one carousel. */
.hero-carousel { min-width: 0; }
.carousel-viewport {
  position: relative;
  overflow: hidden;
  aspect-ratio: 4 / 5;
  border-radius: var(--radius-image);
  background: var(--surface-photo);
  touch-action: pan-y;
}
.carousel-viewport:focus-visible { outline-offset: 6px; }
.carousel-slide {
  position: absolute;
  inset: 0;
  opacity: 0;
  visibility: hidden;
  transform: scale(0.99);
  transition: opacity 260ms ease-out, transform 260ms var(--ease-out), visibility 0s linear 260ms;
}
.carousel-slide.is-active { opacity: 1; visibility: visible; transform: scale(1); transition-delay: 0s; }
.carousel-slide img { width: 100%; height: 100%; object-fit: contain; }
.carousel-topline {
  position: absolute;
  z-index: 2;
  top: 16px;
  right: 16px;
  left: 16px;
  display: flex;
  justify-content: space-between;
  gap: 16px;
  color: var(--text-muted);
  font-size: 9px;
  font-weight: 700;
  letter-spacing: 0.1em;
  pointer-events: none;
}
.carousel-caption {
  position: absolute;
  z-index: 2;
  bottom: 16px;
  left: 16px;
  max-width: calc(100% - 144px);
  display: grid;
  gap: 1px;
  padding: 9px 13px;
  background: color-mix(in oklab, var(--surface) 90%, transparent);
  border: 1px solid color-mix(in oklab, var(--surface) 70%, transparent);
  border-radius: 10px;
  backdrop-filter: blur(12px);
  pointer-events: none;
}
.carousel-caption strong { font-size: 13px; line-height: 1.45; }
.carousel-caption span { color: var(--text-muted); font-size: 10px; line-height: 1.5; }
.carousel-arrows { position: absolute; z-index: 3; right: 16px; bottom: 16px; display: flex; gap: 8px; }
.icon-button {
  width: 44px;
  height: 44px;
  display: inline-grid;
  place-items: center;
  color: var(--text);
  background: color-mix(in oklab, var(--surface) 92%, transparent);
  border: 1px solid var(--divider);
  border-radius: 50%;
  transition: background-color 180ms ease-out, transform 180ms var(--ease-out);
}
.icon-button svg { width: 18px; height: 18px; fill: none; stroke: currentColor; stroke-width: 1.6; }
.icon-button:hover { background: var(--accent); transform: translateY(-2px); }
.icon-button:active { transform: translateY(0); }
.carousel-tabs { margin-top: 12px; display: grid; grid-template-columns: repeat(2, 1fr); gap: 8px; }
.carousel-tab {
  min-height: 48px;
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 9px 11px;
  color: var(--text-muted);
  background: transparent;
  border: 1px solid var(--divider);
  border-radius: 10px;
  text-align: left;
  font-size: 12px;
  transition: color 180ms ease-out, background-color 180ms ease-out, border-color 180ms ease-out;
}
.carousel-tab > span { font-size: 9px; font-weight: 700; letter-spacing: 0.06em; }
.carousel-tab[aria-current="true"] { color: var(--text); background: color-mix(in oklab, var(--accent) 14%, var(--surface)); border-color: var(--accent); }
.carousel-tab:hover { color: var(--text); border-color: var(--accent); }
.autoplay-toggle {
  min-height: 44px;
  margin-left: auto;
  display: block;
  padding: 8px 4px 8px 16px;
  color: var(--text-muted);
  background: transparent;
  border: 0;
  font-size: 12px;
  transition: color 180ms ease-out;
}
.autoplay-toggle:hover { color: var(--accent-text); }

.fact-strip { border-block: 1px solid var(--divider); }
.fact-grid { display: grid; }
.fact { display: grid; gap: 4px; padding-block: 24px; border-bottom: 1px solid var(--divider); }
.fact:last-child { border-bottom: 0; }
.fact-label { color: var(--text-muted); font-size: 12px; }
.fact strong { font-size: 17px; font-weight: 650; }

.about-section { padding-block: var(--section-space); }
.section-note { color: var(--accent-text); font-size: 11px; font-weight: 750; letter-spacing: 0.13em; }
.about-grid { margin-top: 28px; display: grid; gap: 40px; }
.about-grid h2, .states-heading h2, .system-heading h2 {
  font-size: clamp(42px, 10vw, 76px);
  font-weight: 750;
  line-height: 1.02;
  letter-spacing: -0.055em;
}
.about-grid h2 span, .system-heading h2 span { color: var(--accent); }
.about-copy { max-width: 590px; color: var(--text-muted); font-size: 17px; line-height: 1.9; }
.about-copy p + p { margin-top: 20px; }

.states-section { padding-block: var(--section-space); color: var(--surface); background: var(--text); }
.states-section .section-note { color: var(--surface); opacity: 0.7; }
.states-heading h2 { margin-top: 20px; }
.state-grid { margin-top: 48px; display: grid; border-top: 1px solid oklch(0.34 0 0); }
.state-item { padding-block: 32px; border-bottom: 1px solid oklch(0.34 0 0); }
.state-item > span { color: var(--surface); opacity: 0.65; font-size: 10px; font-weight: 700; letter-spacing: 0.12em; }
.state-item h3 { margin-top: 12px; font-size: 32px; line-height: 1.2; letter-spacing: -0.035em; }
.state-item p { max-width: 470px; margin-top: 14px; color: var(--surface); opacity: 0.76; }
.state-item a { min-height: 44px; width: fit-content; margin-top: 18px; display: inline-flex; align-items: center; color: var(--surface); font-size: 13px; font-weight: 650; border-bottom: 1px solid oklch(0.55 0 0); transition: color 180ms ease-out, border-color 180ms ease-out; }
.state-item a:hover { color: var(--accent); border-color: var(--accent); }
.state-item a:focus-visible { outline-color: var(--surface); }

.system-section { padding-block: var(--section-space); }
.system-heading { margin-top: 28px; display: grid; gap: 28px; }
.system-heading > p { max-width: 520px; color: var(--text-muted); font-size: 17px; line-height: 1.9; }
.system-showcase { margin-top: 56px; display: grid; gap: 48px; }
.system-points { border-top: 1px solid var(--divider); }
.system-points article { padding-block: 24px; border-bottom: 1px solid var(--divider); }
.system-points article > span { color: var(--accent-text); font-size: 10px; font-weight: 700; letter-spacing: 0.11em; }
.system-points h3 { margin-top: 10px; font-size: 24px; line-height: 1.3; letter-spacing: -0.025em; }
.system-points p { margin-top: 10px; color: var(--text-muted); font-size: 15px; line-height: 1.8; }
.system-screens { display: grid; gap: 32px; }
.system-screens figure { min-width: 0; }
.system-screen { padding: 12px; background: var(--surface-photo); border: 1px solid var(--divider); border-radius: var(--radius-image); }
.system-screen img { width: 100%; height: auto; border-radius: 10px; }
.system-screens figcaption { margin-top: 16px; display: grid; gap: 2px; }
.system-screens figcaption strong { font-size: 18px; line-height: 1.5; }
.system-screens figcaption span { color: var(--text-muted); font-size: 13px; }

.promo-section { padding-block: 80px; color: var(--text); background: var(--accent); }
.promo-inner > p { font-size: 13px; font-weight: 700; letter-spacing: 0.06em; }
.promo-inner h2 { max-width: 1100px; margin-top: 28px; font-size: clamp(42px, 10vw, 94px); line-height: 1.05; letter-spacing: -0.055em; }
.promo-bottom { margin-top: 56px; padding-top: 24px; display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 20px; border-top: 1px solid color-mix(in oklab, var(--text) 28%, transparent); font-size: 14px; font-weight: 650; }
.promo-bottom a { min-height: 48px; display: inline-flex; align-items: center; gap: 12px; padding: 10px 18px; color: var(--text); background: var(--surface); border-radius: 999px; transition: transform 200ms var(--ease-out), opacity 200ms ease-out; }
.promo-bottom a:hover { transform: translateY(-2px); opacity: 0.9; }
.promo-bottom a:active { transform: translateY(0); }
.promo-bottom a:focus-visible { outline-color: var(--text); }
.contact-section { background: var(--surface); }
.contact-inner { padding-block: 64px; display: grid; gap: 36px; }
.contact-copy h2 { margin-top: 12px; font-size: clamp(42px, 9vw, 64px); font-weight: 750; line-height: 1.1; letter-spacing: -0.045em; }
.contact-copy > p:not(.section-note) { margin-top: 14px; color: var(--text-muted); font-size: 15px; }
.contact-email { width: fit-content; min-height: 48px; margin-top: 16px; display: inline-flex; align-items: center; color: var(--accent-text); border-bottom: 1px solid var(--accent); font-size: 20px; font-weight: 650; overflow-wrap: anywhere; transition: color 180ms ease-out, border-color 180ms ease-out; }
.contact-email:hover { color: var(--text); border-color: var(--text); }
.wechat-contact { display: flex; align-items: center; gap: 16px; }
.wechat-qr-button { min-width: 44px; min-height: 44px; padding: 0; flex: 0 0 auto; background: transparent; border: 0; border-radius: 8px; cursor: zoom-in; }
.wechat-contact img { width: 104px; height: auto; border: 1px solid var(--divider); border-radius: 8px; image-rendering: pixelated; transition: border-color 180ms ease-out; }
.wechat-qr-button:hover img { border-color: var(--accent-text); }
.wechat-contact > div { display: grid; gap: 3px; }
.wechat-title { display: flex; align-items: baseline; gap: 8px; }
.wechat-contact strong { font-size: 16px; }
.wechat-contact small { color: var(--accent-text); font-size: 10px; font-weight: 500; white-space: nowrap; }
.wechat-contact span { color: var(--text-muted); font-size: 12px; }
body.qr-dialog-open { overflow: hidden; }
.qr-dialog { width: fit-content; max-width: calc(100% - 32px); max-height: calc(100dvh - 32px); margin: auto; padding: 0; color: var(--text); background: var(--surface); border: 0; border-radius: 18px; box-shadow: 0 24px 80px oklch(0.1 0 0 / 0.25); }
.qr-dialog::backdrop { background: oklch(0.1 0 0 / 0.66); backdrop-filter: blur(4px); }
.qr-dialog-inner { padding: 18px; }
.qr-dialog-topline { margin-bottom: 14px; display: flex; align-items: center; justify-content: space-between; gap: 24px; }
.qr-dialog-topline h2 { font-size: 16px; line-height: 1.4; }
.qr-dialog-close { width: 44px; height: 44px; display: grid; place-items: center; flex: 0 0 auto; color: var(--text); background: var(--surface-photo); border: 1px solid var(--divider); border-radius: 50%; }
.qr-dialog-close:hover { background: var(--accent); }
.qr-dialog-close svg { width: 18px; height: 18px; fill: none; stroke: currentColor; stroke-width: 1.6; }
.qr-dialog > .qr-dialog-inner > img { width: 392px; max-width: 100%; height: auto; margin-inline: auto; border: 1px solid var(--divider); border-radius: 8px; image-rendering: pixelated; }
.qr-dialog-inner > p { margin-top: 12px; color: var(--text-muted); font-size: 12px; text-align: center; }
.site-footer { color: var(--surface); background: var(--text); }
.footer-inner { min-height: 152px; padding-block: 32px; display: grid; align-content: center; gap: 20px; font-size: 12px; }
.footer-product, .footer-legal { display: flex; flex-wrap: wrap; align-items: center; gap: 8px 24px; }
.footer-product { justify-content: space-between; }
.footer-product span:last-child { opacity: 0.65; }
.footer-legal { opacity: 0.72; }

@media (min-width: 700px) {
  :root { --page-gutter: 40px; --section-space: 136px; }
  .header-status { display: inline-flex; }
  .hero { padding-block: 56px 80px; }
  .carousel-tabs { grid-template-columns: repeat(4, 1fr); }
  .fact-grid { grid-template-columns: repeat(3, 1fr); }
  .fact { padding: 28px 24px; border-right: 1px solid var(--divider); border-bottom: 0; }
  .fact:first-child { padding-left: 0; }
  .fact:last-child { border-right: 0; }
  .about-grid { grid-template-columns: minmax(0, 1.15fr) minmax(300px, 0.85fr); align-items: start; gap: 64px; }
  .about-copy { padding-top: 12px; }
  .states-heading { display: grid; grid-template-columns: 0.55fr 1fr; align-items: start; }
  .states-heading h2 { margin-top: 0; }
  .state-grid { grid-template-columns: 1fr 1fr; }
  .state-item { padding: 40px; }
  .state-item:first-child { padding-left: 0; border-right: 1px solid oklch(0.34 0 0); }
  .state-item:last-child { border-bottom: 0; }
  .system-heading { grid-template-columns: minmax(0, 1.15fr) minmax(280px, 0.85fr); align-items: start; gap: 64px; }
  .system-heading > p { padding-top: 12px; }
  .system-screens { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 24px; }
  .system-points article { padding-block: 28px; }
  .contact-inner { padding-block: 72px; grid-template-columns: minmax(0, 1fr) auto; align-items: center; gap: 64px; }
  .wechat-contact img { width: 112px; }
}

@media (min-width: 1080px) {
  .hero { min-height: calc(100dvh - 76px); grid-template-columns: minmax(0, 1.02fr) minmax(440px, 0.98fr); align-items: stretch; gap: 64px; }
  .hero-copy { padding-top: 24px; }
  .hero h1 { margin-top: auto; font-size: clamp(112px, 10.4vw, 166px); }
  .hero-intro { margin-top: 48px; margin-bottom: 12px; }
  .hero-carousel { display: flex; flex-direction: column; justify-content: center; }
  .carousel-viewport { aspect-ratio: auto; height: clamp(500px, 60dvh, 660px); }
  .system-showcase { grid-template-columns: minmax(300px, 0.8fr) minmax(0, 1.2fr); align-items: start; gap: 72px; }
  .system-points article:first-child { padding-top: 32px; }
  .system-points article:last-child { padding-bottom: 32px; }
}

@media (max-width: 699px) {
  .mobile-break { display: block; }
  .header-inner { gap: 16px; }
  .brand { flex-shrink: 0; }
  .main-nav { min-width: 0; flex: 1; gap: 18px; overflow-x: auto; scrollbar-width: none; }
  .main-nav::-webkit-scrollbar { display: none; }
  .main-nav a { flex-shrink: 0; font-size: 12px; }
  .brand { font-size: 14px; }
  .brand-mark { width: 10px; height: 10px; }
  .version-line > span:first-child { max-width: 190px; line-height: 1.5; }
  .carousel-caption { max-width: calc(100% - 136px); padding: 8px 10px; }
  .carousel-caption span { display: none; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
}