:root {
  color-scheme: light;
  --ink: #162234;
  --muted: #5f6d7c;
  --line: #dce5f2;
  --paper: #f6f9ff;
  --white: #ffffff;
  --blue-tint: #e7f1ff;
  --blue: #087cf0;
  --blue-dark: #075bb8;
  --shadow: 0 22px 65px rgba(25, 65, 120, 0.07);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Microsoft YaHei", sans-serif;
  line-height: 1.65;
}

a { color: var(--blue-dark); }

a:hover { color: var(--blue); }

code { overflow-wrap: anywhere; }

.skip-link {
  position: absolute;
  inset-inline-start: 1rem;
  top: -4rem;
  z-index: 20;
  padding: 0.6rem 1rem;
  background: var(--white);
  border-radius: 0.5rem;
}

.skip-link:focus { top: 0.6rem; }

.shell { width: min(1120px, calc(100% - 2.5rem)); margin-inline: auto; }

.site-header {
  position: relative;
  z-index: 2;
  border-bottom: 1px solid rgba(22, 34, 52, 0.08);
  background: rgba(246, 249, 255, 0.94);
}

.header-inner {
  min-height: 78px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  color: var(--ink);
  font-size: 1.15rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  text-decoration: none;
}

.app-icon {
  display: block;
  object-fit: contain;
  border-radius: 22%;
}

.brand-mark { width: 34px; height: 34px; flex: 0 0 auto; }

a:focus-visible, select:focus-visible { outline: 3px solid var(--blue); outline-offset: 4px; }

nav { display: flex; align-items: center; flex-wrap: wrap; gap: 1.25rem; }

nav a {
  color: var(--muted);
  font-size: 0.9rem;
  font-weight: 600;
  text-decoration: none;
}

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

.language-picker { margin-inline-start: auto; }

.language-picker select {
  max-width: 190px;
  padding-block: 0.55rem;
  padding-inline: 0.7rem 1.7rem;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--white);
  color: var(--ink);
  font: inherit;
  font-size: 0.85rem;
  font-weight: 600;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.hero {
  position: relative;
  overflow: hidden;
  padding: clamp(4rem, 8vw, 7rem) 0 5rem;
  background: radial-gradient(circle at 83% 23%, #dceeff 0, transparent 32%),
    radial-gradient(circle at 93% 82%, #edf4ff 0, transparent 31%), var(--paper);
}

.hero-grid { display: grid; grid-template-columns: 1.2fr 0.8fr; align-items: center; gap: 3rem; }

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  color: var(--blue-dark);
  font-size: 0.79rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.eyebrow::before { content: ""; width: 8px; height: 8px; border-radius: 50%; background: var(--blue); }

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

h1 {
  max-width: 12ch;
  margin: 1rem 0 1.1rem;
  font-size: clamp(2.8rem, 6vw, 5.3rem);
  line-height: 1.1;
  letter-spacing: -0.055em;
}

.hero-copy { max-width: 56ch; color: var(--muted); font-size: clamp(1rem, 1.6vw, 1.16rem); }

.hero-actions { display: flex; gap: 0.7rem; flex-wrap: wrap; margin-top: 1.8rem; }

.button {
  display: inline-flex;
  justify-content: center;
  align-items: center;
  min-height: 47px;
  padding: 0.7rem 1.2rem;
  border: 1px solid var(--blue-dark);
  border-radius: 12px;
  background: var(--blue-dark);
  color: var(--white);
  font-weight: 700;
  text-decoration: none;
  transition: transform 150ms ease, background-color 150ms ease;
}

.button:hover { background: var(--blue); color: var(--white); transform: translateY(-2px); }

.button.secondary { background: transparent; color: var(--blue-dark); }

.button.secondary:hover { background: var(--blue-tint); color: var(--blue-dark); }

.button.is-pending {
  border-color: #d5dfec;
  background: #edf1f7;
  color: #606d80;
  cursor: not-allowed;
  pointer-events: none;
}

.button.secondary.is-pending { background: transparent; }

.note { color: var(--muted); font-size: 0.86rem; }

.hero-note { margin-top: 1rem; }

.product-scene {
  position: relative;
  min-height: 360px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1.4rem;
}

.product-scene::before {
  content: "";
  position: absolute;
  width: 320px;
  height: 320px;
  border: 1px solid rgba(8, 124, 240, 0.12);
  border-radius: 50%;
  box-shadow: 0 0 0 44px rgba(8, 124, 240, 0.03);
}

.scene-product { position: relative; min-width: 0; text-align: center; }
.scene-app { width: 200px; margin-top: -3rem; }
.scene-helper { width: 154px; margin-top: 5rem; }
.scene-product .app-icon { width: 100%; height: auto; box-shadow: 0 18px 40px rgba(18, 94, 192, 0.18); }
.scene-product span { display: block; margin-top: 1rem; font-size: 0.95rem; font-weight: 700; }
.scene-product small { display: block; margin-top: 0.1rem; color: var(--muted); font-size: 0.8rem; font-weight: 500; }

.section { padding: 5rem 0; }

.section.alt { background: var(--white); }

.section-head { max-width: 680px; margin-bottom: 2rem; }

h2 { margin: 0.6rem 0 0.6rem; font-size: clamp(2rem, 3.2vw, 2.8rem); line-height: 1.22; letter-spacing: -0.035em; }

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

.download-panel {
  border: 1px solid var(--line);
  border-radius: 22px;
  background: var(--white);
  box-shadow: var(--shadow);
  overflow: hidden;
}

.product-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 0.85fr);
  align-items: center;
  gap: 1.4rem 3rem;
  padding: 1.8rem 2rem;
}

.product-row:first-child { background: #f3f8ff; }
.product-row + .product-row { border-top: 1px solid var(--line); }
.product-details, .product-actions { min-width: 0; }
.product-actions { display: flex; flex-direction: column; align-items: stretch; }
.product-actions .button { align-self: flex-start; }
.app-actions .button { align-self: flex-end; }

.card-tag { color: var(--blue-dark); font-size: 0.75rem; font-weight: 700; letter-spacing: 0.1em; text-transform: uppercase; }

.product-row h3 { margin: 0.3rem 0 0; font-size: 1.35rem; line-height: 1.25; }

.product-details p { margin-bottom: 0; color: var(--muted); font-size: 0.94rem; }

.product-heading { display: flex; align-items: center; gap: 1rem; margin-bottom: 1rem; }
.product-heading > div { min-width: 0; }
.product-icon { width: 72px; height: 72px; flex: 0 0 auto; }

.source-picker { min-width: 0; margin: 0 0 1.3rem; padding: 0; border: 0; }
.source-picker legend { margin-bottom: 0.6rem; padding: 0; color: var(--muted); font-size: 0.82rem; font-weight: 600; }
.source-options { display: flex; border: 1px solid var(--line); border-radius: 12px; overflow: hidden; }
.source-option { display: flex; flex: 1; min-width: 0; align-items: center; gap: 0.65rem; padding: 0.8rem 1rem; cursor: pointer; }
.source-option + .source-option { border-inline-start: 1px solid var(--line); }
.source-option:has(input:checked) { background: var(--blue-tint); color: var(--blue-dark); }
.source-option:has(input:focus-visible) { outline: 2px solid var(--blue); outline-offset: -3px; }
.source-option input { margin: 0; flex: 0 0 auto; accent-color: var(--blue); }
.source-option strong { display: block; font-size: 0.88rem; line-height: 1.4; }
.source-option small { display: block; margin-top: 0.2rem; color: var(--muted); font-size: 0.75rem; }
.helper-release { grid-column: 1 / -1; padding-top: 1rem; border-top: 1px solid var(--line); }
.helper-release p { margin-bottom: 0.25rem; font-size: 0.8rem; }
.helper-release p:last-child { margin-bottom: 0; }

.steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1.5rem; }

.step { border-top: 1px solid var(--line); padding-top: 1.25rem; }

.step-number { color: var(--blue); font-size: 0.82rem; font-weight: 700; letter-spacing: 0.1em; }

.step h3 { margin: 0.7rem 0 0.5rem; }

.step p { color: var(--muted); }

.callout { padding: 1.8rem; border: 1px solid #dce1e7; border-radius: 18px; background: #f1f3f6; color: #374357; }
.callout a { color: #4e6076; }
.callout p { margin-bottom: 0; color: #657082; }
.callout p + p { margin-top: 0.7rem; }
.legacy-callout { display: flex; align-items: center; gap: 1.5rem; }
.legacy-icon { width: 100px; height: 100px; flex: 0 0 auto; }
.legacy-callout .card-tag { color: #657082; }
.legacy-callout h2 { margin-top: 0.4rem; font-size: 1.5rem; }

.page-hero { padding: 4.5rem 0 2.3rem; }

.page-hero h1 { max-width: 18ch; font-size: clamp(2.5rem, 5vw, 4rem); }

.page-hero p { max-width: 66ch; color: var(--muted); }

.document { max-width: 780px; padding-bottom: 5rem; }

.document h2 { margin-top: 2.7rem; font-size: 1.5rem; }

.document p, .document li { color: #425367; }

.document ul { padding-inline-start: 1.35rem; }

.document li { margin-bottom: 0.5rem; }

.draft-banner {
  padding: 1rem 1.25rem;
  border: 1px solid #e5c697;
  border-radius: 14px;
  background: #fff6e8;
  color: #72451d;
  font-size: 0.92rem;
}

.faq { display: grid; gap: 0.75rem; }

.faq article { padding: 1.2rem 1.4rem; border: 1px solid var(--line); border-radius: 14px; background: var(--white); }

.faq h3 { margin-bottom: 0.35rem; font-size: 1rem; }

.faq p { margin: 0; font-size: 0.92rem; }

.site-footer { padding: 2.4rem 0; border-top: 1px solid var(--line); background: var(--white); }

.footer-inner { display: flex; justify-content: space-between; gap: 1rem; flex-wrap: wrap; align-items: center; }

.footer-links { display: flex; flex-wrap: wrap; gap: 1.1rem; }

.footer-links a { color: var(--muted); font-size: 0.88rem; text-decoration: none; }

.footer-links a:hover { color: var(--blue-dark); }

@media (max-width: 860px) {
  .hero-grid { grid-template-columns: 1fr; }
  .product-scene { min-height: 280px; }
  .product-scene::before { width: 230px; height: 230px; box-shadow: 0 0 0 35px rgba(8, 124, 240, 0.03); }
  .scene-app { width: 160px; }
  .scene-helper { width: 130px; margin-top: 3rem; }
  .product-row { grid-template-columns: 1fr; gap: 1.2rem; }
  .app-actions .button { align-self: flex-start; }
}

@media (max-width: 600px) {
  .shell { width: min(100% - 1.5rem, 1120px); }
  .header-inner { align-items: flex-start; flex-direction: column; padding: 1rem 0; }
  nav { gap: 0.8rem 1.1rem; }
  .language-picker { margin-inline-start: 0; }
  .hero { padding: 3rem 0 4rem; }
  .hero-grid { gap: 1.5rem; }
  .product-scene { gap: 1rem; }
  .scene-app { width: 145px; }
  .scene-helper { width: 115px; }
  .product-row { padding: 1.25rem; }
  .source-option { padding: 0.75rem; gap: 0.5rem; }
  .legacy-callout { align-items: flex-start; flex-direction: column; }
  .legacy-icon { width: 72px; height: 72px; }
  .section { padding: 3.4rem 0; }
  .steps { grid-template-columns: 1fr; }
  .page-hero { padding: 3rem 0 1.5rem; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .button { transition: none; }
}