/* Shared sizing and touch controls. */
html { scroll-padding-top: 110px; -webkit-text-size-adjust: 100%; }
body { padding-left: env(safe-area-inset-left); padding-right: env(safe-area-inset-right); }
img, svg { max-width: 100%; }
.hero > *, .products > *, .steps > *, .trust-layout > *, .company > *, .section-heading > * { min-width: 0; }
.nav { gap: 24px; }
.brand { flex-shrink: 0; }
.brand .mark { flex-shrink: 0; }
.desktop-nav { gap: 22px; }
.desktop-nav a { display: inline-flex; align-items: center; min-height: 44px; white-space: nowrap; }
.controls { align-items: center; gap: 10px; flex-shrink: 0; }
.controls select { height: 44px; min-width: 92px; max-width: none; font-size: 16px; padding: 6px 10px; }
.theme-controls { display: inline-flex; align-items: center; border: 1px solid var(--line); border-radius: 7px; padding: 2px; gap: 2px; }
.theme-controls button { display: grid; place-items: center; background: transparent; color: var(--muted); border: 0; border-radius: 4px; width: 44px; height: 44px; padding: 10px; touch-action: manipulation; }
.theme-controls button[aria-pressed="true"] { color: var(--accent); background: var(--soft); }
.theme-controls button:hover { color: var(--ink); }
.theme-controls svg { width: 22px; height: 22px; pointer-events: none; }
.hero-art { isolation: isolate; }
.hero { grid-template-columns: minmax(0,1.03fr) minmax(0,1fr); }
.mock-stats { grid-template-columns: repeat(3,minmax(0,1fr)); }
.preview-title, .product-type { flex-wrap: wrap; row-gap: 8px; }
.product-type { column-gap: 16px; }
.erp-float .label { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 6px 12px; }
.erp-flow span { text-align: center; }
.products { grid-template-columns: repeat(2,minmax(0,1fr)); }
.tabs { flex-wrap: wrap; }
.tabs button, .btn { min-height: 44px; touch-action: manipulation; }
.faq summary { min-height: 44px; padding-block: 8px; }
.legal p, .legal a, .product .api { overflow-wrap: anywhere; }
.footer-links a { display: inline-flex; align-items: center; min-height: 44px; }
.footer-top > .brand { align-self: flex-start; }
.mobile-menu { display: none; }

/* Tablets, including landscape: give navigation a dedicated row. */
@media (max-width: 1120px) {
  html { scroll-padding-top: 140px; }
  .wrap { width: calc(100% - 64px); }
  .nav { display: grid; grid-template-columns: minmax(0,1fr) auto; height: auto; min-height: 116px; gap: 4px 24px; padding-block: 12px 6px; }
  .nav > .brand { grid-column: 1; grid-row: 1; }
  .nav > .controls { grid-column: 2; grid-row: 1; }
  .desktop-nav { grid-column: 1 / -1; grid-row: 2; justify-content: space-between; gap: 20px; font-size: 14px; }
  .hero { gap: 36px; padding-block: 64px 52px; min-height: 580px; }
  h1 { font-size: 50px; }
  html[lang="zh-CN"] h1 { font-size: 46px; }
  h2 { font-size: 34px; }
  .hero .lead { font-size: 16px; }
  .hero-art { padding-right: 12px; }
  .orbit { width: 320px; height: 320px; right: 5px; }
  .erp-float { margin-left: 28px; margin-right: 0; padding: 20px; }
  .erp-flow { gap: 6px; }
  .erp-flow span { padding: 6px 9px; }
  section.block { padding-block: 70px; }
  .products { gap: 20px; }
  .product { padding: 28px; }
  .product h3 { font-size: 26px; }
  .workflow { padding: 36px; }
  .steps { gap: 24px; }
  .trust-layout, .company { grid-template-columns: repeat(2,minmax(0,1fr)); gap: 40px; }
  .contact { padding: 40px; }
  .contact h2 { font-size: 30px; }
  .contact a { font-size: 20px; }
  .intro-line { gap: 24px; }
}

/* Portrait tablets: let the hero breathe while keeping the two systems side by side. */
@media (max-width: 960px) {
  .hero { grid-template-columns: 1fr; min-height: 0; gap: 20px; }
  .hero > div:first-child { max-width: 680px; }
  .hero .lead { max-width: 640px; }
  .hero h1 { font-size: clamp(44px,6.6vw,62px); }
  html[lang="zh-CN"] .hero h1 { font-size: clamp(40px,6vw,56px); }
  .hero-art { width: 100%; max-width: 540px; margin: 0 auto; padding: 18px 14px 20px; }
  .orbit { width: 380px; height: 380px; max-width: 90%; right: 12px; }
  .section-heading { align-items: start; gap: 28px; }
  .section-heading > div, .section-heading > p { flex: 1; }
  .product { padding: 24px; }
  .intro-line { flex-wrap: wrap; gap: 12px 28px; }
  .intro-line > span { flex-basis: 100%; }
  .workflow { padding: 30px; }
  .steps { gap: 20px; }
  .trust-layout, .company { gap: 30px; }
  .contact { display: block; }
  .contact a { display: inline-block; margin-top: 24px; }
  .footer-top, .footer-bottom { flex-direction: column; gap: 18px; }
  .footer-links { gap: 12px 24px; }
  .legal { padding-block: 52px 72px; }
}

/* Phones: compact, accessible header with a native disclosure menu. */
@media (max-width: 700px) {
  html { scroll-padding-top: 142px; }
  .wrap { width: calc(100% - 36px); }
  .nav { position: relative; min-height: 122px; grid-template-columns: minmax(0,1fr) 44px; gap: 8px 14px; padding-block: 10px; }
  .brand strong { font-size: 19px; letter-spacing: 1.7px; }
  .brand small { font-size: 9px; letter-spacing: 1.7px; }
  .brand .mark { width: 30px; height: 36px; }
  .nav > .controls { grid-column: 1 / -1; grid-row: 2; justify-content: space-between; gap: 12px; }
  .controls select { min-width: 110px; }
  .nav > .desktop-nav { display: none; }
  .mobile-menu { display: block; grid-column: 2; grid-row: 1; }
  .mobile-menu summary { display: grid; place-items: center; width: 44px; height: 44px; padding: 10px; border: 1px solid var(--line); border-radius: 6px; cursor: pointer; list-style: none; }
  .mobile-menu summary::-webkit-details-marker { display: none; }
  .mobile-menu[open] summary { background: var(--soft); color: var(--accent); }
  .mobile-menu nav { position: absolute; top: calc(100% - 1px); left: 0; right: 0; display: grid; grid-template-columns: repeat(2,minmax(0,1fr)); gap: 6px; padding: 12px; background: var(--surface); border: 1px solid var(--line); border-radius: 0 0 8px 8px; box-shadow: 0 16px 26px #0002; }
  .mobile-menu nav a { display: flex; align-items: center; min-height: 48px; padding: 10px; font-size: 15px; }
  .mobile-menu nav a:hover { background: var(--soft); }
  .hero { padding-block: 40px 30px; gap: 12px; }
  .hero h1 { font-size: clamp(39px,8.5vw,52px); letter-spacing: -1.6px; }
  html[lang="zh-CN"] .hero h1 { font-size: clamp(34px,8vw,46px); letter-spacing: -1px; }
  .hero .lead { font-size: 16px; line-height: 1.85; }
  .eyebrow { font-size: 11px; letter-spacing: 1.2px; gap: 8px; margin-bottom: 20px; }
  .eyebrow::before { flex-shrink: 0; }
  .actions { gap: 12px; margin-block: 26px; }
  .btn { padding: 12px 17px; gap: 16px; }
  .hero-art { padding: 18px 6px 10px; max-width: 480px; }
  .app-preview { transform: none; }
  .app-top { padding: 16px; }
  .preview-body { padding: 16px; }
  .preview-title { align-items: start; }
  .mock-stats { gap: 7px; }
  .mock-stats div { padding: 10px 8px; }
  .mock-stats small { font-size: 11px; }
  .mock-stats b { font-size: 19px; }
  .chart { height: auto; aspect-ratio: 400 / 135; }
  .erp-float { transform: none; margin: 12px 0 0 16px; padding: 18px; }
  .erp-float .label { font-size: 10px; letter-spacing: .6px; }
  .erp-flow { font-size: 12px; gap: 5px; }
  .erp-flow span { padding: 6px; }
  .art-caption { font-size: 10px; letter-spacing: .6px; line-height: 1.8; margin-top: 14px; }
  .orbit { width: 280px; height: 280px; right: 0; }
  .intro-line { font-size: 12px; padding-block: 22px; gap: 12px; }
  .intro-line > b { flex-basis: 100%; }
  section.block { padding-block: 52px; }
  .section-heading { display: block; margin-bottom: 28px; }
  .section-heading p { max-width: none; margin-top: 20px; }
  h2 { font-size: 30px; }
  .products, .trust-layout, .company, .steps { grid-template-columns: 1fr; gap: 24px; }
  .product { padding: 24px; }
  .product h3 { font-size: 26px; }
  .product p, .product li, .trust-list p, .company p, .details dd { font-size: 15px; }
  .product-type { font-size: 10px; gap: 8px 14px; }
  .product .api { font-size: 12px; }
  .note { font-size: 14px; }
  .workflow { padding: 24px; margin-top: 30px; }
  .workflow h3 { font-size: 26px; }
  .steps article { padding-top: 18px; }
  .steps h4 { margin-block: 8px; font-size: 18px; }
  .steps p { font-size: 15px; }
  .tabs { gap: 8px; }
  .tabs button { font-size: 14px; padding: 8px 17px; }
  .trust-list { margin-top: 10px; }
  .faq h2 { margin-bottom: 24px; }
  .faq details { padding-block: 12px; }
  .faq summary { font-size: 17px; }
  .faq details p { padding: 12px 0 6px; font-size: 15px; }
  .contact { padding: 28px; margin-block: 0 48px; }
  .contact h2 { font-size: 28px; }
  .contact a { white-space: normal; overflow-wrap: anywhere; font-size: 20px; }
  .footer-links { gap: 4px 22px; }
  footer { padding-top: 30px; padding-bottom: max(24px,env(safe-area-inset-bottom)); }
  .legal { padding-block: 36px 60px; }
  .legal h1, html[lang="zh-CN"] .legal h1 { font-size: 34px; letter-spacing: -1px; }
  .legal h2 { font-size: 23px; }
  .legal .notice { padding: 20px; }
  .legal p, .legal li { font-size: 16px; }
}

@media (max-width: 380px) {
  .wrap { width: calc(100% - 32px); }
  .brand strong { font-size: 18px; }
  .brand small { font-size: 8px; }
  .controls select { min-width: 100px; }
  .hero h1 { font-size: 39px; }
  html[lang="zh-CN"] .hero h1 { font-size: 34px; }
  .actions { display: grid; grid-template-columns: 1fr; }
  .product, .workflow { padding: 20px; }
  .preview-body { padding: 12px; }
  .mock-stats div { padding: 8px 6px; }
  .mock-stats b { font-size: 18px; }
  .erp-float { margin-left: 0; padding: 15px; }
  .erp-flow { gap: 4px; font-size: 11px; }
  .contact { padding: 22px; }
}

/* Keep small landscape viewports from being dominated by a sticky header. */
@media (max-height: 500px) and (orientation: landscape) { .top { position: relative; } html { scroll-padding-top: 20px; } }
@media (min-width: 1500px) { .hero { min-height: 720px; } }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }