:root {
  color-scheme: light;
  --page: #f6f8fb;
  --surface: rgba(255, 255, 255, 0.86);
  --surface-strong: #ffffff;
  --ink: #172033;
  --muted: #687389;
  --line: #e3e8f0;
  --blue: #5877cf;
  --blue-soft: #eef3ff;
  --mint: #4f9f91;
  --mint-soft: #edf8f5;
  --shadow: 0 18px 48px rgba(39, 54, 86, 0.08);
  --radius-lg: 26px;
  --radius-md: 20px;
}

* {
  box-sizing: border-box;
}

html {
  min-width: 320px;
  background: var(--page);
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-width: 320px;
  min-height: 100vh;
  color: var(--ink);
  background:
    radial-gradient(circle at 9% 6%, rgba(117, 150, 230, 0.11), transparent 25rem),
    radial-gradient(circle at 92% 92%, rgba(90, 184, 157, 0.10), transparent 25rem),
    var(--page);
  font-family: Inter, "SF Pro Display", "PingFang SC", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  -webkit-font-smoothing: antialiased;
}

a {
  color: inherit;
}

.page-shell {
  width: min(1480px, 100%);
  min-height: 100svh;
  margin: 0 auto;
  padding: 0 clamp(24px, 4vw, 64px);
  display: grid;
  grid-template-rows: auto 1fr auto;
}

.site-header {
  min-height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  border-bottom: 1px solid rgba(213, 220, 232, 0.75);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 11px;
  color: var(--ink);
  font-size: 1.08rem;
  font-weight: 750;
  letter-spacing: -0.025em;
  text-decoration: none;
}

.brand-mark {
  width: 34px;
  height: 34px;
  display: grid;
  place-items: center;
  color: white;
  background: linear-gradient(145deg, #7089d7, #4b6fc8);
  border-radius: 11px;
  box-shadow: 0 8px 22px rgba(75, 111, 200, 0.24);
  font-size: 0.95rem;
  font-weight: 800;
}

.header-actions,
.intro-actions,
.site-footer > div {
  display: flex;
  align-items: center;
}

.header-actions {
  gap: 24px;
}

.status {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--muted);
  font-size: 0.82rem;
}

.status i {
  width: 7px;
  height: 7px;
  background: #5ab69d;
  border-radius: 50%;
  box-shadow: 0 0 0 4px rgba(90, 182, 157, 0.12);
}

.header-link,
.text-button,
.inline-link {
  text-underline-offset: 4px;
  text-decoration-thickness: 1px;
}

.header-link {
  color: var(--ink);
  font-size: 0.88rem;
  font-weight: 650;
  text-decoration: none;
}

.landing {
  min-height: 0;
  padding: clamp(18px, 2.8vh, 34px) 0;
  display: grid;
  grid-template-columns: minmax(330px, 0.82fr) minmax(620px, 1.58fr);
  gap: clamp(18px, 2vw, 28px);
}

.intro,
.feature-card {
  border: 1px solid rgba(220, 226, 236, 0.9);
  box-shadow: var(--shadow);
}

.intro {
  min-height: 0;
  padding: clamp(28px, 4.3vh, 54px) clamp(26px, 3vw, 48px);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: clamp(22px, 3vh, 36px);
  overflow: hidden;
  background: linear-gradient(150deg, rgba(255,255,255,0.96), rgba(239,244,255,0.89));
  border-radius: var(--radius-lg);
}

.eyebrow,
.card-kicker {
  margin: 0;
  color: var(--blue);
  font-size: 0.68rem;
  font-weight: 780;
  letter-spacing: 0.16em;
}

.intro h1 {
  margin: clamp(12px, 2vh, 22px) 0 14px;
  /* Large screens: fluid title, capped at about 46px. */
  font-size: clamp(2rem, 3.2vw, 2.85rem);
  line-height: 1.45;
  letter-spacing: 0;
}

.intro h1 span {
  color: var(--blue);
}

.intro-copy {
  max-width: 29rem;
  margin: 0;
  color: var(--muted);
  font-size: clamp(0.95rem, 1.1vw, 1.08rem);
  line-height: 1.75;
}

.offer {
  display: grid;
  grid-template-columns: 1fr;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.offer-item {
  min-width: 0;
  padding: 11px 0;
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
}

.offer-item + .offer-item {
  border-top: 1px solid var(--line);
}

.offer-item strong {
  white-space: nowrap;
  font-size: clamp(0.98rem, 1.25vw, 1.22rem);
  letter-spacing: -0.03em;
}

.offer-item span {
  color: var(--muted);
  font-size: 0.72rem;
  white-space: nowrap;
}

.intro-actions {
  gap: 20px;
}

.primary-button {
  min-height: 48px;
  padding: 0 22px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 22px;
  color: white;
  background: var(--ink);
  border-radius: 14px;
  box-shadow: 0 12px 28px rgba(23, 32, 51, 0.16);
  font-size: 0.9rem;
  font-weight: 680;
  text-decoration: none;
  transition: transform 160ms ease, box-shadow 160ms ease;
}

.primary-button:hover {
  transform: translateY(-2px);
  box-shadow: 0 15px 32px rgba(23, 32, 51, 0.22);
}

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

.feature-grid {
  min-height: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  grid-template-rows: repeat(2, minmax(0, 1fr));
  gap: clamp(14px, 1.6vw, 22px);
}

.feature-card {
  min-height: 0;
  padding: clamp(21px, 2.4vw, 32px);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: clamp(12px, 1.7vh, 19px);
  background: var(--surface);
  border-radius: var(--radius-md);
  backdrop-filter: blur(12px);
}

.route-card {
  background: linear-gradient(145deg, rgba(255,255,255,0.95), rgba(238,248,245,0.92));
}

.share-card {
  background: linear-gradient(145deg, rgba(255,255,255,0.96), rgba(239,243,254,0.92));
}

.card-heading {
  display: flex;
  align-items: flex-start;
  gap: 13px;
}

.card-number {
  flex: 0 0 auto;
  width: 31px;
  height: 31px;
  display: grid;
  place-items: center;
  color: var(--blue);
  background: var(--blue-soft);
  border-radius: 10px;
  font-size: 0.69rem;
  font-weight: 800;
}

.feature-card h2 {
  margin: 4px 0 0;
  font-size: clamp(1.12rem, 1.45vw, 1.45rem);
  line-height: 1.25;
  letter-spacing: -0.035em;
}

.feature-card p {
  margin: 0;
  color: var(--muted);
  font-size: clamp(0.8rem, 0.89vw, 0.93rem);
  line-height: 1.66;
}

.route-list {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 8px;
}

.route-list span {
  padding: 9px 8px;
  color: #48635e;
  background: var(--mint-soft);
  border: 1px solid #dceee9;
  border-radius: 10px;
  font-size: clamp(0.7rem, 0.78vw, 0.8rem);
  text-align: center;
  white-space: nowrap;
}

.route-list b {
  font-weight: 750;
}

.feature-card .card-note {
  padding-left: 10px;
  color: #4d6c65;
  border-left: 2px solid #83c4b5;
}

.compact-card {
  justify-content: flex-start;
}

.inline-link {
  width: fit-content;
  color: var(--blue);
  font-size: 0.8rem;
  font-weight: 650;
}

.share-content {
  display: grid;
  grid-template-columns: auto 1fr;
  align-items: center;
  gap: 18px;
}

.share-content strong {
  color: var(--blue);
  font-size: clamp(2.3rem, 3.3vw, 3.5rem);
  line-height: 1;
  letter-spacing: -0.07em;
}

.site-footer {
  min-height: 58px;
  display: flex;
  align-items: center;
  gap: clamp(24px, 4vw, 52px);
  border-top: 1px solid rgba(213, 220, 232, 0.75);
  color: var(--muted);
  font-size: 0.78rem;
}

.site-footer > div {
  gap: 10px;
}

.site-footer span {
  color: #939cad;
}

.site-footer a {
  color: var(--ink);
  font-weight: 650;
  text-decoration: none;
}

.site-footer small {
  margin-left: auto;
  color: #9aa2b1;
}

a:focus-visible {
  outline: 3px solid rgba(88, 119, 207, 0.34);
  outline-offset: 4px;
}

@media (min-width: 980px) and (min-height: 700px) {
  body {
    overflow: hidden;
  }

  .page-shell {
    height: 100svh;
  }
}

@media (max-width: 1150px) and (min-width: 821px) {
  .page-shell {
    padding-inline: 24px;
  }

  .landing {
    grid-template-columns: minmax(300px, 0.75fr) minmax(540px, 1.35fr);
    gap: 16px;
  }

  .feature-grid {
    gap: 14px;
  }

  .intro,
  .feature-card {
    padding: 22px;
  }

  .intro h1 {
    /* Narrow desktop/tablet: overrides the base title size. */
    font-size: 2.25rem;
  }

  .feature-card p {
    font-size: 0.78rem;
  }
}

@media (max-height: 760px) and (min-width: 980px) {
  .site-header {
    min-height: 60px;
  }

  .site-footer {
    min-height: 48px;
  }

  .landing {
    padding-block: 14px;
  }

  .intro {
    gap: 16px;
    padding-block: 24px;
  }

  .feature-card {
    gap: 9px;
    padding-block: 18px;
  }

  .feature-card p {
    line-height: 1.5;
  }

  .offer-item {
    padding-block: 12px;
  }
}

@media (max-width: 820px) {
  body {
    background:
      radial-gradient(circle at 5% 2%, rgba(117, 150, 230, 0.12), transparent 20rem),
      var(--page);
  }

  .page-shell {
    padding: 0 18px;
  }

  .site-header {
    min-height: 64px;
  }

  .status {
    display: none;
  }

  .landing {
    padding: 16px 0 22px;
    display: block;
  }

  .intro {
    min-height: auto;
    padding: 30px 24px;
    gap: 28px;
  }

  .intro h1 {
    margin-top: 14px;
    /* Mobile: overrides the base title size. */
    font-size: clamp(2rem, 9vw, 3rem);
  }

  .intro-copy {
    font-size: 1rem;
  }

  .feature-grid {
    margin-top: 16px;
    display: grid;
    grid-template-columns: 1fr;
    grid-template-rows: none;
    gap: 14px;
  }

  .feature-card {
    padding: 24px;
    gap: 16px;
  }

  .feature-card p {
    font-size: 0.92rem;
  }

  .site-footer {
    padding: 20px 0 28px;
    flex-wrap: wrap;
    gap: 12px 24px;
  }

  .site-footer small {
    width: 100%;
    margin: 4px 0 0;
  }
}

@media (max-width: 460px) {
  .brand-mark {
    width: 31px;
    height: 31px;
  }

  .header-link {
    padding: 8px 0;
  }

  .offer {
    grid-template-columns: 1fr;
  }

  .offer-item {
    padding: 10px 0;
    flex-direction: row;
    align-items: baseline;
    justify-content: space-between;
  }

  .offer-item + .offer-item {
    border-top: 1px solid var(--line);
    border-left: 0;
  }

  .intro-actions {
    align-items: stretch;
    flex-direction: column;
  }

  .primary-button {
    width: 100%;
  }

  .text-button {
    text-align: center;
  }

  .route-list {
    grid-template-columns: 1fr;
  }

  .share-content {
    grid-template-columns: 1fr;
    gap: 10px;
  }

  .site-footer > div {
    width: 100%;
    justify-content: space-between;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .primary-button {
    transition: none;
  }
}

/* Clear navigation and a visible brand status across screen sizes. */
.brand-copy {
  display: flex;
  flex-direction: column;
  gap: 5px;
}

.brand-copy .status {
  display: inline-flex;
  gap: 7px;
  font-size: 0.65rem;
  font-weight: 500;
  letter-spacing: 0.04em;
}

.brand-copy .status i {
  width: 5px;
  height: 5px;
  box-shadow: 0 0 0 3px rgba(90, 182, 157, 0.12);
}

.header-actions {
  gap: 10px;
}

.header-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 20px;
  color: #435f9d;
  background: #eef3ff;
  border: 1px solid #cdd9ef;
  border-radius: 12px;
  box-shadow: 0 3px 8px rgba(39, 54, 86, 0.05);
  font-size: 0.95rem;
  font-weight: 700;
  white-space: nowrap;
}

.header-link:hover {
  background: #e2eaff;
  border-color: #9cb1dc;
}

@media (max-width: 460px) {
  .site-header {
    gap: 10px;
    min-height: 78px;
  }

  .brand {
    gap: 8px;
    font-size: 0.98rem;
  }

  .header-actions {
    gap: 7px;
  }

  .header-link {
    padding-inline: 11px;
    font-size: 0.82rem;
    border-radius: 10px;
  }
}

@media (max-width: 350px) {
  .site-header {
    flex-wrap: nowrap;
    padding-block: 0;
  }

  .header-actions {
    width: auto;
  }

  .header-actions .header-link {
    flex: 0 0 auto;
  }
}

/* Shared floating navigation for the landing and public help pages. */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  isolation: isolate;
  background: transparent;
  border-bottom: 0;
}

.site-header::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 50%;
  z-index: -1;
  width: 100vw;
  transform: translateX(-50%);
  background: rgba(246, 248, 251, 0.90);
  border-bottom: 1px solid rgba(213, 220, 232, 0.75);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  pointer-events: none;
}

.site-footer {
  scroll-margin-top: 76px;
  background: rgba(246, 248, 251, 0.94);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
}

.site-footer a {
  min-height: 36px;
  padding: 0 12px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: #435f9d;
  background: #eef3ff;
  border: 1px solid #cdd9ef;
  border-radius: 10px;
  box-shadow: 0 3px 8px rgba(39, 54, 86, 0.05);
  white-space: nowrap;
}

.site-footer a:hover {
  background: #e2eaff;
  border-color: #9cb1dc;
}

.footer-jump {
  display: none;
}

@media (min-width: 821px) {
  .page-shell {
    padding-bottom: 66px;
  }

  .site-footer {
    position: fixed;
    left: 50%;
    right: auto;
    bottom: 0;
    z-index: 45;
    width: min(1480px, 100%);
    min-height: 66px;
    padding: 8px clamp(24px, 4vw, 64px);
    transform: translateX(-50%);
  }
}

@media (max-width: 820px) {
  .site-header {
    min-height: 64px;
  }

  .header-link {
    min-height: 38px;
    padding: 0 13px;
    font-size: 0.84rem;
  }

  .site-footer {
    padding: 16px 0 20px;
  }

  .site-footer a {
    min-height: 30px;
    padding-inline: 9px;
    border-radius: 8px;
  }

  .footer-jump {
    position: fixed;
    right: 18px;
    bottom: 18px;
    z-index: 60;
    min-height: 44px;
    padding: 0 16px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    color: white;
    background: rgba(23, 32, 51, 0.94);
    border: 1px solid rgba(255, 255, 255, 0.18);
    border-radius: 14px;
    box-shadow: 0 12px 30px rgba(23, 32, 51, 0.22);
    font-size: 0.82rem;
    font-weight: 700;
    text-decoration: none;
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    transition: opacity 160ms ease, transform 160ms ease;
  }

  .footer-jump.is-hidden {
    opacity: 0;
    transform: translateY(8px);
    pointer-events: none;
  }
}

@media (max-width: 460px) {
  .site-header {
    min-height: 64px;
  }

  .header-link {
    min-height: 36px;
    padding-inline: 9px;
    font-size: 0.78rem;
  }

  .site-footer {
    padding: 14px 0 18px;
    gap: 8px 20px;
  }

  .site-footer small {
    margin-top: 0;
  }

  .site-footer a {
    min-height: 26px;
    padding-inline: 7px;
    border-radius: 7px;
    box-shadow: none;
  }
}

@media (max-width: 350px) {
  .site-header {
    gap: 6px;
    min-height: 62px;
  }

  .brand {
    gap: 6px;
    font-size: 0.9rem;
  }

  .brand-mark {
    width: 29px;
    height: 29px;
  }

  .brand-copy .status {
    font-size: 0.58rem;
  }

  .header-actions {
    gap: 5px;
  }

  .header-link {
    min-height: 34px;
    padding-inline: 7px;
    font-size: 0.73rem;
  }

  .footer-jump {
    right: 14px;
    bottom: 14px;
  }
}