:root {
  --ink: #0f172a;
  --muted: #64748b;
  --line: #e2e8f0;
  --bg: #f1f5f9;
  --surface: #ffffff;
  --indigo: #6366f1;
  --indigo-d: #4f46e5;
  --cyan: #06b6d4;
  --violet: #8b5cf6;
  --amber: #f59e0b;
  --max: 1080px;
  --hh: 64px;
  --r: 14px;
  --shadow: 0 1px 2px rgba(15, 23, 42, 0.06), 0 4px 12px rgba(15, 23, 42, 0.06);
  --shadow-hover: 0 4px 6px rgba(15, 23, 42, 0.05), 0 12px 28px rgba(15, 23, 42, 0.06);
  --font: system-ui, -apple-system, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font: 15px/1.65 var(--font);
  color: var(--ink);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }

.wrap { width: 100%; max-width: var(--max); margin: 0 auto; padding: 0 20px; }

/* header */
.hdr {
  position: sticky;
  top: 0;
  z-index: 50;
  height: var(--hh);
  /* 不透明白底，避免滚过页脚时底部 Logo 透过顶栏产生「重影」 */
  background: #fff;
  border-bottom: 1px solid rgba(226, 232, 240, 0.9);
}
.hdr__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--hh);
}

.logo { display: flex; align-items: center; gap: 10px; font-weight: 800; }
.logo__mark {
  width: 38px;
  height: 38px;
  border-radius: 10px;
  background: linear-gradient(135deg, var(--indigo) 0%, var(--cyan) 100%);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  box-shadow: 0 2px 8px rgba(99, 102, 241, 0.35);
}
.logo__txt { display: flex; flex-direction: column; line-height: 1.15; }
.logo__txt small {
  font-size: 0.65rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  color: var(--muted);
  text-transform: uppercase;
}
.logo--ft .logo__txt small { color: var(--muted); }
.logo--ft { color: var(--ink); }
.logo--ft .logo__mark { box-shadow: none; }

.hdr__toggle {
  display: none;
  width: 42px;
  height: 42px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--surface);
  cursor: pointer;
  padding: 0;
  align-items: center;
  justify-content: center;
}
.hdr__toggle span,
.hdr__toggle span::before,
.hdr__toggle span::after {
  display: block;
  width: 18px;
  height: 2px;
  background: var(--ink);
  position: relative;
}
.hdr__toggle span::before,
.hdr__toggle span::after { content: ""; position: absolute; left: 0; }
.hdr__toggle span::before { top: -6px; }
.hdr__toggle span::after { top: 6px; }

.nav { display: flex; align-items: center; gap: 2px; }
.nav a {
  padding: 8px 12px;
  border-radius: 999px;
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--muted);
}
.nav a:hover { color: var(--ink); background: rgba(99, 102, 241, 0.08); }
.nav__cta {
  background: linear-gradient(135deg, var(--indigo-d), #0891b2) !important;
  color: #fff !important;
  margin-left: 6px;
  box-shadow: 0 2px 8px rgba(79, 70, 229, 0.25);
}
.nav__cta:hover {
  filter: brightness(1.05);
  color: #fff !important;
}

@media (max-width: 768px) {
  .hdr__toggle { display: flex; }
  .nav {
    display: none;
    position: fixed;
    top: var(--hh);
    left: 0;
    right: 0;
    background: var(--surface);
    border-bottom: 1px solid var(--line);
    flex-direction: column;
    align-items: stretch;
    padding: 12px 20px 18px;
    gap: 4px;
    box-shadow: var(--shadow);
  }
  .nav.is-open { display: flex; }
  .nav__cta { margin-left: 0; text-align: center; }
}

/* hero */
.hero {
  position: relative;
  padding: 44px 0 52px;
  overflow: hidden;
}
.hero__bg {
  position: absolute;
  inset: 0;
  z-index: 0;
  background:
    radial-gradient(ellipse 80% 55% at 50% -20%, rgba(99, 102, 241, 0.22), transparent 55%),
    radial-gradient(ellipse 60% 40% at 100% 30%, rgba(6, 182, 212, 0.12), transparent 50%),
    radial-gradient(ellipse 50% 35% at 0% 60%, rgba(139, 92, 246, 0.1), transparent 45%),
    linear-gradient(180deg, #eef2ff 0%, #f8fafc 50%, var(--bg) 100%);
  pointer-events: none;
}
.hero__intro {
  position: relative;
  z-index: 1;
  padding: 0 0 32px;
  text-align: center;
  max-width: 40em;
  margin: 0 auto;
}
.hero__eyebrow {
  margin: 0 0 10px;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--indigo-d);
}
.hero__title {
  margin: 0 0 14px;
  font-size: clamp(1.65rem, 4.2vw, 2.15rem);
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.03em;
  color: var(--ink);
}
.hero__accent {
  background: linear-gradient(90deg, var(--indigo) 0%, var(--cyan) 55%, #a855f7 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.hero__lead {
  margin: 0 auto;
  font-size: 0.9375rem;
  color: var(--muted);
  line-height: 1.75;
  max-width: 36em;
}
.hero__chips {
  display: grid;
  grid-template-columns: repeat(2, max-content);
  justify-content: center;
  align-items: center;
  column-gap: 16px;
  row-gap: 10px;
  margin: 22px auto 0;
  width: 100%;
  max-width: 36em;
  padding: 0;
  box-sizing: border-box;
}
.hero__chip--wide {
  grid-column: 1 / -1;
  justify-self: center;
}
/* PC：三条要点单行横排；H5 保持上方网格两行布局 */
@media (min-width: 640px) {
  .hero__chips {
    display: flex;
    flex-direction: row;
    flex-wrap: nowrap;
    justify-content: center;
    align-items: center;
    gap: 12px 18px;
  }
}
@media (max-width: 480px) {
  .hero__chips {
    column-gap: 10px;
    row-gap: 8px;
  }
}
.hero__chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.8125rem;
  font-weight: 600;
  color: #475569;
  padding: 8px 14px;
  background: rgba(255, 255, 255, 0.72);
  border: 1px solid rgba(226, 232, 240, 0.9);
  border-radius: 999px;
  box-shadow: 0 1px 2px rgba(15, 23, 42, 0.04);
}
.hero__chip-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--chip, var(--indigo));
  flex-shrink: 0;
}

.biz-core {
  position: relative;
  z-index: 1;
  display: grid;
  gap: 14px;
  grid-template-columns: 1fr;
}
@media (min-width: 640px) {
  .biz-core { grid-template-columns: 1fr 1fr; gap: 16px; }
}

.biz-core__card {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 8px;
  padding: 22px 20px;
  border-radius: var(--r);
  background: var(--surface);
  border: 1px solid var(--line);
  box-shadow: var(--shadow);
  transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
  min-height: 168px;
}
.biz-core__card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-hover);
}
.biz-core__tag {
  font-size: 0.65rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
}
.biz-core__name {
  font-size: 1.2rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--ink);
}
.biz-core__desc {
  font-size: 0.8125rem;
  color: var(--muted);
  line-height: 1.6;
  flex: 1;
}
.biz-core__link {
  font-size: 0.8125rem;
  font-weight: 700;
  margin-top: 4px;
}
.biz-core__foot {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 12px;
  width: 100%;
  margin-top: 4px;
}
.biz-core__foot .biz-core__link {
  margin-top: 0;
}
.biz-core__foot .biz-core__dl {
  margin-top: 0;
  padding-top: 0;
  border-top: none;
  width: auto;
  flex: 0 1 auto;
}

.biz-core__main {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 8px;
  flex: 1;
  width: 100%;
  min-height: 0;
  color: inherit;
}
.biz-core__main:hover .biz-core__name {
  color: var(--ink);
}

.biz-core__head {
  display: flex;
  align-items: center;
  gap: 14px;
  width: 100%;
}
.biz-core__logo {
  width: 56px;
  height: 56px;
  object-fit: contain;
  border-radius: 14px;
  flex-shrink: 0;
  background: #fff;
  border: 1px solid rgba(226, 232, 240, 0.95);
}
.biz-core__card--b .biz-core__logo {
  border-color: rgba(124, 58, 237, 0.2);
  background: linear-gradient(180deg, #faf5ff 0%, #fff 100%);
}
.biz-core__card--a .biz-core__logo {
  border-color: rgba(234, 88, 12, 0.18);
  background: #fff;
}
.biz-core__head-text {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 4px;
  min-width: 0;
}
.biz-core__head-text .biz-core__tag { margin: 0; }
.biz-core__head-text .biz-core__name { margin: 0; }

.biz-core__dl {
  width: 100%;
  margin-top: 4px;
  padding-top: 14px;
  border-top: 1px solid rgba(226, 232, 240, 0.95);
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
}
.biz-core__dl-link {
  font-size: 0.75rem;
  font-weight: 700;
  padding: 7px 12px;
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.85);
  border: 1px solid var(--line);
  transition: background 0.15s ease, border-color 0.15s ease;
}
.biz-core__dl-link:hover {
  background: var(--surface);
  border-color: #cbd5e1;
}
.biz-core__dl-link--ghost {
  font-weight: 600;
  background: transparent;
}
.biz-core__card--b .biz-core__dl-link { color: #6d28d9; border-color: rgba(124, 58, 237, 0.25); }
.biz-core__card--b .biz-core__dl-link:hover { border-color: #7c3aed; }
.biz-core__card--b .biz-core__dl-link--ghost { color: #7c3aed; }
.biz-core__card--a .biz-core__dl-link { color: #c2410c; border-color: rgba(234, 88, 12, 0.28); }
.biz-core__card--a .biz-core__dl-link:hover { border-color: #ea580c; }

.biz-core__card--a {
  border-top: 4px solid #ea580c;
  background: linear-gradient(180deg, #fff7ed 0%, var(--surface) 38%);
}
.biz-core__card--a .biz-core__link { color: #c2410c; }

.biz-core__card--b {
  border-top: 4px solid #7c3aed;
  background: linear-gradient(180deg, #f5f3ff 0%, var(--surface) 38%);
}
.biz-core__card--b .biz-core__link { color: #6d28d9; }

.biz-core__card--c {
  border-top: 4px solid #0891b2;
  background: linear-gradient(180deg, #ecfeff 0%, var(--surface) 38%);
}
.biz-core__card--c .biz-core__link { color: #0e7490; }

.biz-core__card--d {
  border-top: 4px solid #059669;
  background: linear-gradient(180deg, #ecfdf5 0%, var(--surface) 38%);
}
.biz-core__card--d .biz-core__link { color: #047857; }

.biz-core__card--e {
  border-top: 4px solid #db2777;
  background: linear-gradient(180deg, #fdf2f8 0%, var(--surface) 38%);
}
.biz-core__card--e .biz-core__link { color: #be185d; }

/* section common */
.sec { padding: 52px 0; }
.sec__label {
  margin: 0 0 6px;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--indigo-d);
}
.sec__label--center { text-align: center; }
.sec__h {
  margin: 0 0 14px;
  font-size: 1.45rem;
  font-weight: 800;
  letter-spacing: -0.02em;
}
.sec__h--center { text-align: center; }
.sec__p {
  margin: 0 0 18px;
  color: var(--muted);
  max-width: 40em;
  line-height: 1.75;
  font-size: 0.9375rem;
}
.sec__p--center { margin-left: auto; margin-right: auto; text-align: center; }
.sec__p--flush { margin-bottom: 14px; }
.sec__p--flush:last-child { margin-bottom: 0; }

/* overview */
.sec--overview {
  background: var(--surface);
  border-top: 1px solid var(--line);
}
.split {
  display: grid;
  gap: 28px;
  align-items: start;
}
@media (min-width: 800px) {
  .split { grid-template-columns: 1.3fr 1fr; gap: 40px; }
}
.checklist {
  margin: 0;
  padding: 0;
  list-style: none;
}
.checklist li {
  position: relative;
  padding-left: 22px;
  margin-bottom: 14px;
  font-size: 0.875rem;
  color: #475569;
  line-height: 1.65;
}
.checklist li:last-child { margin-bottom: 0; }
.checklist li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.45em;
  width: 10px;
  height: 10px;
  border-radius: 3px;
  background: linear-gradient(135deg, var(--indigo), var(--cyan));
}
.checklist strong {
  display: block;
  color: var(--ink);
  font-size: 0.8125rem;
  margin-bottom: 2px;
}

/* about */
.sec--about { background: linear-gradient(180deg, #f8fafc 0%, var(--surface) 24%); }
.about-row { display: grid; gap: 12px; }
@media (min-width: 640px) {
  .about-row { grid-template-columns: repeat(3, 1fr); }
}
.about-box {
  position: relative;
  padding: 18px 16px 16px;
  border-radius: var(--r);
  border: 1px solid var(--line);
  background: var(--surface);
  font-size: 0.8125rem;
  color: var(--muted);
  line-height: 1.55;
  box-shadow: 0 1px 2px rgba(15, 23, 42, 0.04);
  overflow: hidden;
}
.about-box__icon {
  position: absolute;
  top: 10px;
  right: 12px;
  font-size: 0.65rem;
  font-weight: 800;
  letter-spacing: 0.06em;
  color: rgba(100, 116, 139, 0.45);
}
.about-box b {
  display: block;
  font-size: 1.05rem;
  font-weight: 800;
  color: var(--ink);
  margin-bottom: 4px;
  line-height: 1.3;
}
.about-box--1 { border-top: 3px solid var(--indigo); }
.about-box--2 { border-top: 3px solid var(--cyan); }
.about-box--3 { border-top: 3px solid var(--violet); }

/* pillars */
.sec--pillars {
  background: radial-gradient(ellipse 70% 50% at 50% 0%, rgba(99, 102, 241, 0.06), transparent 55%), var(--bg);
}
.pill-row { display: grid; gap: 14px; }
@media (min-width: 700px) {
  .pill-row { grid-template-columns: repeat(3, 1fr); }
}
.pill {
  padding: 22px 20px;
  border-radius: var(--r);
  background: var(--surface);
  border: 1px solid var(--line);
  box-shadow: var(--shadow);
}
.pill h3 {
  margin: 0 0 10px;
  font-size: 1rem;
  font-weight: 800;
  color: var(--ink);
}
.pill p {
  margin: 0;
  font-size: 0.8125rem;
  color: var(--muted);
  line-height: 1.65;
}
.pill--violet { border-left: 4px solid var(--violet); }
.pill--cyan { border-left: 4px solid var(--cyan); }
.pill--amber { border-left: 4px solid var(--amber); }

/* audience */
.sec--audience {
  background: var(--surface);
  border-top: 1px solid var(--line);
}
.aud-grid {
  display: grid;
  gap: 14px;
}
@media (min-width: 720px) {
  .aud-grid { grid-template-columns: repeat(3, 1fr); }
}
.aud-card {
  padding: 20px 18px;
  border-radius: var(--r);
  background: #f8fafc;
  border: 1px solid #e2e8f0;
}
.aud-card__h {
  margin: 0 0 10px;
  font-size: 0.9375rem;
  font-weight: 800;
  color: var(--ink);
}
.aud-card p {
  margin: 0;
  font-size: 0.8125rem;
  color: var(--muted);
  line-height: 1.65;
}

/* contact */
.sec--contact { padding: 48px 0 56px; }
.contact {
  padding: 0;
  border-radius: var(--r);
  overflow: hidden;
  border: 1px solid var(--line);
  background: linear-gradient(145deg, #f8fafc 0%, #f1f5f9 50%, #eef2ff 100%);
  box-shadow: var(--shadow-hover);
}
.contact__inner {
  display: grid;
  gap: 28px;
  padding: 28px 24px;
}
@media (min-width: 720px) {
  .contact__inner {
    grid-template-columns: 1fr 1fr;
    align-items: start;
    padding: 32px 32px;
    gap: 40px;
  }
}
.contact__label {
  margin: 0 0 6px;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--indigo-d);
}
.contact__h {
  margin: 0 0 12px;
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--ink);
  letter-spacing: -0.02em;
}
.contact__p {
  margin: 0 0 14px;
  font-size: 0.875rem;
  line-height: 1.7;
  color: var(--muted);
}
.contact__p strong { color: var(--ink); }
.contact__list {
  margin: 0;
  padding-left: 1.25em;
  font-size: 0.8125rem;
  color: var(--muted);
  line-height: 1.75;
}
.contact__actions {
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.contact__hint {
  margin: 8px 0 0;
  font-size: 0.75rem;
  color: var(--muted);
  line-height: 1.55;
}
.contact__links {
  padding-top: 4px;
}
.contact__links-h {
  margin: 0 0 14px;
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--ink);
}
.contact__tags {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  margin-bottom: 16px;
}
.contact__tag {
  padding: 8px 14px;
  background: rgba(99, 102, 241, 0.08);
  border: 1px solid rgba(99, 102, 241, 0.2);
  border-radius: 999px;
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--indigo-d);
}
.contact__note {
  margin: 0;
  font-size: 0.8125rem;
  color: var(--muted);
  line-height: 1.6;
}
  color: #94a3b8;
  line-height: 1.6;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 20px;
  border-radius: 10px;
  font-size: 0.875rem;
  font-weight: 700;
  border: none;
  cursor: pointer;
  text-align: center;
}
.btn--pri {
  background: linear-gradient(135deg, var(--indigo-d), #2563eb);
  color: #fff;
  box-shadow: 0 4px 14px rgba(79, 70, 229, 0.25);
}
.btn--pri:hover { filter: brightness(1.06); }
.btn--sec {
  background: rgba(99, 102, 241, 0.08);
  color: var(--indigo-d);
  border: 1px solid rgba(99, 102, 241, 0.2);
}
.btn--sec:hover {
  background: rgba(99, 102, 241, 0.12);
  border-color: rgba(99, 102, 241, 0.35);
}

/* footer：默认与 H5 共用扁平行内式；PC 端见下方 min-width:640px */
.ft {
  padding: 28px 0 18px;
  background: #f1f5f9;
  color: var(--muted);
  border-top: 1px solid var(--line);
}
.ft__grid {
  display: grid;
  gap: 18px 40px;
  margin-bottom: 18px;
  align-items: start;
}
.ft__brand .ft__tag { margin: 10px 0 0; }
.ft__tag { margin: 10px 0 0; font-size: 0.8125rem; color: var(--muted); line-height: 1.5; }
.ft__nav {
  display: flex;
  flex-direction: column;
  gap: 8px;
  min-width: 0;
}
.ft__row {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  column-gap: 12px;
  row-gap: 4px;
}
.ft__label {
  flex: 0 0 auto;
  min-width: 2em;
  font-size: 0.75rem;
  font-weight: 500;
  color: #94a3b8;
  letter-spacing: 0.04em;
}
.ft__links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 4px 14px;
  flex: 1;
  min-width: 0;
}
.ft__links a {
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--muted);
  padding: 1px 0;
  transition: color 0.15s ease;
}
.ft__links a:hover {
  color: var(--indigo-d);
}
.ft__copy {
  font-size: 0.75rem;
  color: var(--muted);
  padding-top: 14px;
  border-top: 1px solid var(--line);
}

/* PC：横向紧凑；标签与链接分区（竖线 + 字重/色阶） */
@media (min-width: 640px) {
  .ft {
    padding: 20px 0 12px;
    background: #f1f5f9;
  }
  .ft__grid {
    grid-template-columns: minmax(160px, 1fr) minmax(0, 1.85fr);
    gap: 12px 36px;
    align-items: center;
    margin-bottom: 10px;
  }
  .ft__brand .ft__tag {
    margin-top: 6px;
  }
  .ft__nav {
    flex-direction: column;
    align-items: stretch;
    gap: 5px;
    min-width: 0;
  }
  .ft__row {
    display: flex;
    flex-direction: row;
    flex-wrap: wrap;
    align-items: center;
    justify-content: flex-start;
    column-gap: 0;
    row-gap: 4px;
  }
  .ft__label {
    flex: 0 0 3em;
    box-sizing: content-box;
    text-align: left;
    font-size: 0.875rem;
    font-weight: 700;
    letter-spacing: 0.04em;
    color: var(--indigo-d);
    padding-right: 10px;
    margin-right: 10px;
    border-right: 1px solid #94a3b8;
    line-height: 1.35;
  }
  .ft__links {
    flex-direction: row;
    flex-wrap: wrap;
    align-items: center;
    justify-content: flex-start;
    gap: 4px 14px;
    flex: 1 1 auto;
    min-width: 0;
  }
  .ft__links a {
    font-size: 0.8125rem;
    font-weight: 500;
    color: #1e293b;
    padding: 1px 0;
    line-height: 1.4;
  }
  .ft__links a:hover {
    color: var(--indigo-d);
  }
  .ft__copy {
    padding-top: 10px;
  }
}
/* H5：标签像小徽标，和链接一眼可分 */
@media (max-width: 639px) {
  .ft {
    padding: 18px 0 12px;
  }
  .ft__grid {
    gap: 14px;
    margin-bottom: 12px;
  }
  .ft__brand {
    display: flex;
    align-items: center;
    gap: 12px;
  }
  .ft__brand .ft__tag {
    margin: 0;
  }
  .ft__nav {
    gap: 10px;
  }
  .ft__row {
    align-items: flex-start;
    column-gap: 10px;
    row-gap: 6px;
  }
  .ft__label {
    font-size: 0.75rem;
    font-weight: 700;
    color: var(--indigo-d);
    letter-spacing: 0.06em;
    padding: 4px 10px;
    border-radius: 6px;
    background: rgba(99, 102, 241, 0.12);
    border: 1px solid rgba(99, 102, 241, 0.18);
  }
  .ft__links {
    gap: 4px 12px;
  }
  .ft__links a {
    font-weight: 600;
    color: #475569;
  }
  .ft__links a:hover {
    color: var(--indigo-d);
  }
}

/* back to top */
.back-top {
  position: fixed;
  right: 24px;
  bottom: 96px;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--indigo-d), #0891b2);
  color: #fff;
  border: none;
  font-size: 18px;
  cursor: pointer;
  box-shadow: 0 4px 14px rgba(79, 70, 229, 0.35);
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.25s ease, transform 0.25s ease, visibility 0.25s ease;
  z-index: 100;
}
.back-top.is-visible {
  opacity: 1;
  visibility: visible;
}
.back-top:hover {
  transform: translateY(-3px);
  box-shadow: 0 6px 20px rgba(79, 70, 229, 0.45);
}

/* contact service button */
.contact-service {
  position: fixed;
  right: 24px;
  bottom: 24px;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: linear-gradient(135deg, #10b981, #059669);
  color: #fff;
  border: none;
  cursor: pointer;
  box-shadow: 0 4px 14px rgba(16, 185, 129, 0.35);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: transform 0.25s ease, box-shadow 0.25s ease;
  z-index: 100;
}
.contact-service:hover {
  transform: translateY(-3px);
  box-shadow: 0 6px 20px rgba(16, 185, 129, 0.45);
}
.contact-service svg {
  width: 20px;
  height: 20px;
}

/* qrcode modal */
.qrcode-modal {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.6);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 200;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s ease, visibility 0.3s ease;
}
.qrcode-modal.is-visible {
  opacity: 1;
  visibility: visible;
}
.qrcode-modal__content {
  background: var(--surface);
  border-radius: 16px;
  padding: 32px 32px 24px;
  max-width: 320px;
  width: 90%;
  text-align: center;
  box-shadow: var(--shadow-hover);
  position: relative;
  transform: scale(0.9);
  transition: transform 0.3s ease;
}
.qrcode-modal.is-visible .qrcode-modal__content {
  transform: scale(1);
}
.qrcode-modal__close {
  position: absolute;
  top: 12px;
  right: 12px;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: transparent;
  border: 1px solid var(--line);
  color: var(--muted);
  font-size: 24px;
  line-height: 1;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.15s ease, color 0.15s ease;
}
.qrcode-modal__close:hover {
  background: var(--bg);
  color: var(--ink);
}
.qrcode-modal__title {
  margin: 0 0 20px;
  font-size: 1.125rem;
  font-weight: 800;
  color: var(--ink);
}
.qrcode-modal__qr {
  width: 240px;
  height: 240px;
  margin: 0 auto 16px;
  border-radius: 12px;
  overflow: hidden;
  border: 1px solid var(--line);
  background: #fff;
}
.qrcode-modal__qr img {
  width: 100%;
  height: 100%;
  object-fit: contain;
}
.qrcode-modal__tip {
  margin: 0;
  font-size: 0.875rem;
  color: var(--muted);
}

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