:root {
  --ink: #18202b;
  --muted: #616c7c;
  --line: #d9dee6;
  --paper: #ffffff;
  --wash: #f4f6f8;
  --cobalt: #275ab5;
  --cobalt-dark: #1f478f;
  --amber: #bd7c20;
  --charcoal: #202a38;
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "微软雅黑", Arial, Helvetica, sans-serif;
  color: var(--ink);
  background: var(--paper);
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; color: var(--ink); background: var(--paper); line-height: 1.72; }
a { color: inherit; text-decoration: none; }
img { display: block; max-width: 100%; height: auto; }
button { font: inherit; }
.utility-line { background: var(--charcoal); color: #dbe2eb; font-size: 11px; }
.utility-line > div { width: min(1160px, calc(100% - 48px)); height: 32px; margin: 0 auto; display: flex; align-items: center; justify-content: space-between; }
.masthead { position: sticky; top: 0; z-index: 50; background: rgba(255,255,255,.97); border-bottom: 1px solid var(--line); }
.masthead-inner, .intro-grid, .workflow-band, .content-inner, .final-call, .base-footer > div, .document-head, .document-shell, .support-head, .support-shell { width: min(1160px, calc(100% - 48px)); margin: 0 auto; }
.masthead-inner { min-height: 74px; display: flex; align-items: center; gap: 28px; }
.wordmark { display: flex; align-items: center; gap: 10px; }
.wordmark img { width: 46px; height: 46px; border-radius: 8px; }
.wordmark strong { font-size: 18px; }
.page-nav { margin-left: auto; display: flex; gap: 26px; }
.page-nav a { padding: 24px 0 20px; color: #4e5968; font-size: 14px; font-weight: 800; border-bottom: 3px solid transparent; }
.page-nav a.selected, .page-nav a:hover { color: var(--cobalt); border-color: var(--cobalt); }
.masthead-actions { display: flex; gap: 9px; }
.android-button, .ios-button { min-height: 40px; padding: 0 16px; display: inline-flex; align-items: center; justify-content: center; border-radius: 4px; font-size: 14px; font-weight: 850; }
.android-button { background: var(--cobalt); color: #fff; border: 1px solid var(--cobalt); }
.ios-button { background: #fff; color: var(--cobalt-dark); border: 1px solid #9eb1d4; }
.large { min-height: 48px; padding: 0 24px; }
.menu-button { display: none; border: 0; background: none; font-size: 24px; color: var(--ink); }

.intro-hero { background: var(--wash); border-bottom: 1px solid var(--line); }
.intro-grid { min-height: 590px; display: grid; grid-template-columns: 1.04fr .96fr; gap: 74px; align-items: center; padding: 46px 0; }
.section-code { color: var(--cobalt); font-size: 11px; font-weight: 900; }
.intro-copy h1 { margin: 14px 0 18px; font-size: 51px; line-height: 1.14; letter-spacing: 0; }
.intro-copy > p { margin: 0; color: var(--muted); font-size: 17px; }
.intro-actions { display: flex; gap: 10px; margin-top: 28px; }
.intro-note { margin-top: 32px; padding-top: 18px; border-top: 1px solid var(--line); display: grid; grid-template-columns: auto 1fr auto 1fr; gap: 8px 13px; font-size: 13px; }
.intro-note b { color: var(--cobalt); }
.intro-visual { background: #fff; border: 1px solid var(--line); padding: 18px; box-shadow: 0 22px 50px rgba(32,42,56,.09); }
.visual-caption { display: flex; justify-content: space-between; margin-bottom: 13px; }
.visual-caption b { font-size: 13px; }
.visual-caption span { color: var(--amber); font-size: 12px; font-weight: 800; }
.intro-visual img { width: 100%; max-width: 400px; margin: 0 auto; }
.workflow-band { display: grid; grid-template-columns: repeat(4, 1fr); border-left: 1px solid var(--line); }
.workflow-band > div { min-height: 124px; padding: 22px; border-right: 1px solid var(--line); border-bottom: 1px solid var(--line); display: grid; align-content: center; }
.workflow-band span { color: var(--cobalt); font-weight: 900; font-size: 12px; }
.workflow-band strong { font-size: 17px; }
.workflow-band small { color: var(--muted); }

.content-band { padding: 84px 0; }
.band-heading h2 { margin: 6px 0 0; font-size: 33px; line-height: 1.2; }
.feature-lines { margin-top: 32px; border-top: 1px solid var(--line); }
.feature-lines article { display: grid; grid-template-columns: 90px 1fr; gap: 20px; padding: 24px 0; border-bottom: 1px solid var(--line); }
.feature-lines article > span { color: var(--cobalt); font-size: 22px; font-weight: 900; }
.feature-lines h3 { margin: 0 0 4px; font-size: 20px; }
.feature-lines p { margin: 0; color: var(--muted); }
.steps-band { background: var(--charcoal); color: #fff; }
.steps-grid { display: grid; grid-template-columns: .72fr 1.28fr; gap: 90px; }
.steps-band .section-code { color: #9db9ed; }
.heading-copy { margin: 22px 0; color: #c0c8d3; }
.steps-grid a { color: #fff; font-weight: 850; }
.steps-grid ol { list-style: none; margin: 0; padding: 0; }
.steps-grid li { display: grid; grid-template-columns: 1fr 1.3fr; gap: 20px; padding: 20px 0; border-bottom: 1px solid rgba(255,255,255,.18); }
.steps-grid li:first-child { border-top: 1px solid rgba(255,255,255,.18); }
.steps-grid li span { color: #bdc7d6; }

.decision-band { background: #fff; }
.decision-grid { display: grid; grid-template-columns: .8fr 1.2fr; gap: 80px; align-items: center; }
.decision-image { position: relative; }
.decision-image > span { position: absolute; top: 14px; left: 14px; z-index: 2; padding: 6px 9px; background: var(--charcoal); color: #fff; font-size: 11px; font-weight: 800; }
.decision-image img { max-width: 400px; border: 1px solid var(--line); }
.decision-copy { margin-top: 28px; }
.decision-copy article { padding: 20px 0; border-bottom: 1px solid var(--line); }
.decision-copy h3 { margin: 0 0 5px; }
.decision-copy p { margin: 0; color: var(--muted); }

.visual-band { background: var(--wash); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.visual-pair { margin-top: 32px; display: grid; grid-template-columns: 1.25fr .75fr; gap: 22px; align-items: stretch; }
.visual-pair figure { margin: 0; padding: 18px; background: #fff; border: 1px solid var(--line); display: flex; flex-direction: column; justify-content: center; }
.visual-pair img { max-width: 400px; width: 100%; margin: auto; object-fit: contain; }
.visual-pair figcaption { display: grid; margin-top: 16px; padding-top: 13px; border-top: 1px solid var(--line); }
.visual-pair figcaption span { color: var(--muted); font-size: 13px; }

.answer-grid { display: grid; grid-template-columns: .6fr 1.4fr; gap: 80px; }
.answer-links { border-top: 1px solid var(--line); }
.answer-links a { display: flex; justify-content: space-between; padding: 20px 2px; border-bottom: 1px solid var(--line); font-weight: 780; }
.answer-links b { color: var(--cobalt); }
.final-call { margin-bottom: 84px; padding: 38px 42px; background: #eaf0fb; border-left: 5px solid var(--cobalt); display: flex; align-items: center; justify-content: space-between; gap: 30px; }
.final-call span { color: var(--cobalt); font-size: 12px; font-weight: 850; }
.final-call h2 { margin: 4px 0 0; font-size: 26px; }
.final-call > div:last-child { display: flex; gap: 9px; }

.base-footer { background: #f6f7f9; border-top: 1px solid var(--line); }
.base-footer > div { padding: 32px 0; text-align: center; }
.base-footer a { display: inline-flex; align-items: center; gap: 8px; }
.base-footer img { border-radius: 7px; }
.base-footer p { text-align: center; max-width: 760px; margin: 14px auto 8px; color: var(--muted); font-size: 13px; }
.base-footer small { color: #858d99; }

.document-head, .support-head { min-height: 410px; display: grid; grid-template-columns: 1.15fr .85fr; gap: 80px; align-items: center; padding: 46px 0; }
.document-head h1, .support-head h1 { margin: 13px 0; font-size: 43px; line-height: 1.2; letter-spacing: 0; }
.document-head div > div, .support-head div > div { color: var(--muted); font-size: 16px; }
.document-head img { max-width: 240px; max-height: 290px; justify-self: end; border: 1px solid var(--line); object-fit: contain; }
.support-head img { max-width: 360px; justify-self: end; border: 1px solid var(--line); }
.document-shell { padding: 68px 0 96px; display: grid; grid-template-columns: 210px 1fr; gap: 74px; }
.document-index { position: sticky; top: 110px; align-self: start; display: grid; border-top: 3px solid var(--cobalt); padding-top: 12px; }
.document-index strong, .document-index a { padding: 7px 0; }
.document-index a { color: var(--muted); font-size: 14px; }
.document-body section { display: grid; grid-template-columns: 50px 1fr; gap: 20px; padding-bottom: 38px; margin-bottom: 40px; border-bottom: 1px solid var(--line); scroll-margin-top: 110px; }
.document-body section > span { color: var(--cobalt); font-weight: 900; }
.document-body h2 { margin: -5px 0 12px; font-size: 27px; }
.document-body p { color: #4e5968; }
.document-next { padding: 27px; background: var(--wash); border: 1px solid var(--line); display: flex; justify-content: space-between; align-items: center; }
.document-next span { color: var(--cobalt); font-size: 12px; font-weight: 850; }
.document-next h2 { margin: 4px 0 0; font-size: 21px; }
.document-next a { padding: 10px 17px; background: var(--cobalt); color: #fff; font-weight: 800; }

.support-shell { padding: 64px 0 96px; }
.support-nav { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 30px; }
.support-nav button { padding: 9px 15px; border: 1px solid var(--line); background: #fff; color: var(--muted); cursor: pointer; }
.support-nav button.active { background: var(--charcoal); color: #fff; border-color: var(--charcoal); }
.support-list { border-top: 1px solid var(--line); }
.support-list article { border-bottom: 1px solid var(--line); scroll-margin-top: 105px; }
.support-list article[hidden] { display: none; }
.support-list button { width: 100%; padding: 20px 0; border: 0; background: transparent; color: var(--ink); display: flex; justify-content: space-between; text-align: left; font-weight: 800; cursor: pointer; }
.support-list button b { display: inline-block; width: 44px; color: var(--cobalt); }
.support-list button i { font-size: 20px; color: var(--cobalt); font-style: normal; }
.support-list article > div { display: none; padding: 0 60px 22px 44px; }
.support-list button[aria-expanded="true"] + div { display: block; }
.support-list p { margin: 0; color: var(--muted); }
.support-shell .document-next { margin-top: 52px; }

@media (max-width: 940px) {
  .masthead-inner { flex-wrap: wrap; padding: 12px 0; }
  .menu-button { display: block; margin-left: auto; }
  .page-nav { display: none; order: 4; width: 100%; margin: 0; flex-direction: column; gap: 0; border-top: 1px solid var(--line); }
  .page-nav.open { display: flex; }
  .page-nav a { padding: 10px 0; border-bottom-width: 1px; }
  .masthead-actions { display: none; }
  .intro-grid { grid-template-columns: 1fr 420px; gap: 35px; }
  .intro-copy h1 { font-size: 43px; }
}

@media (max-width: 720px) {
  .utility-line > div, .masthead-inner, .intro-grid, .workflow-band, .content-inner, .final-call, .base-footer > div, .document-head, .document-shell, .support-head, .support-shell { width: min(100% - 32px, 620px); }
  .utility-line > div span:last-child { display: none; }
  .intro-grid { min-height: auto; grid-template-columns: 1fr; gap: 24px; padding: 38px 0 40px; }
  .intro-copy h1 { font-size: 36px; margin: 10px 0 14px; }
  .intro-copy > p { font-size: 15px; }
  .intro-actions { margin-top: 20px; }
  .intro-actions a { flex: 1; padding: 0 10px; }
  .intro-note { display: none; }
  .intro-visual { max-width: 320px; width: 100%; justify-self: center; padding: 12px; }
  .intro-visual img { max-height: 185px; object-fit: contain; }
  .workflow-band { grid-template-columns: 1fr 1fr; }
  .workflow-band > div { min-height: 94px; padding: 16px; }
  .content-band { padding: 60px 0; }
  .band-heading h2 { font-size: 28px; }
  .feature-lines article { grid-template-columns: 55px 1fr; }
  .steps-grid, .decision-grid, .answer-grid { grid-template-columns: 1fr; gap: 32px; }
  .decision-grid > * { min-width: 0; width: 100%; }
  .steps-grid li { grid-template-columns: 1fr; gap: 4px; }
  .decision-image img { width: 100%; margin: 0 auto; }
  .visual-pair { grid-template-columns: 1fr; }
  .visual-pair figure { max-width: 440px; width: 100%; margin: 0 auto; }
  .final-call { margin-bottom: 60px; padding: 28px 22px; flex-direction: column; align-items: stretch; }
  .final-call > div:last-child { flex-direction: column; }
  .document-head, .support-head { min-height: auto; grid-template-columns: 1fr; gap: 26px; padding: 40px 0; }
  .document-head h1, .support-head h1 { font-size: 34px; }
  .document-head img, .support-head img { justify-self: center; max-width: 250px; max-height: 250px; object-fit: contain; }
  .document-shell { grid-template-columns: 1fr; gap: 32px; padding-top: 46px; }
  .document-index { position: static; grid-template-columns: 1fr 1fr; }
  .document-index strong { grid-column: span 2; }
  .document-body section { grid-template-columns: 1fr; gap: 8px; }
  .document-next { flex-direction: column; align-items: stretch; gap: 18px; }
  .document-next a { text-align: center; }
  .support-list button b { display: block; width: auto; margin-bottom: 3px; }
  .support-list article > div { padding-left: 0; padding-right: 28px; }
}

@media (max-width: 390px) {
  .intro-copy h1, .document-head h1, .support-head h1 { font-size: 31px; }
}