:root {
  --navy: #12212e;
  --navy-2: #1d3a52;
  --accent: #1a8f79;
  --accent-dark: #146b5b;
  --accent-soft: rgba(26, 143, 121, 0.1);
  --blue: #4a90cf;             /* 浅蓝点缀 */
  --blue-dark: #2f6ea8;
  --blue-soft: #eef4fa;        /* 浅蓝底 */
  --blue-line: #c9dcef;
  --text: #1a2229;
  --muted: #5f6b76;
  --bg: #ffffff;
  --bg-soft: #f7f5f1;          /* 纸感底色 */
  --line: #dfe3e6;
  --line-strong: #c3cbd1;
  --radius: 3px;
  --shadow: 0 14px 40px rgba(18, 33, 46, 0.07);
  --maxw: 1160px;
  --serif: "Songti SC", "STSong", "Source Han Serif SC", "Noto Serif SC", "SimSun", Georgia, serif;
  --sans: "PingFang SC", "Microsoft YaHei", -apple-system, BlinkMacSystemFont, "Helvetica Neue", Arial, sans-serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--sans);
  color: var(--text);
  background: var(--bg);
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }

.container {
  width: 100%;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 24px;
}

h1, h2, h3, .serif { font-family: var(--serif); font-weight: 600; }

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--line);
}

.header-inner {
  height: 76px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand { display: flex; align-items: center; gap: 12px; }

.brand-mark {
  width: 36px;
  height: 36px;
  background: var(--blue);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--serif);
  font-size: 18px;
  letter-spacing: 1px;
}

.brand-text strong {
  display: block;
  font-family: var(--serif);
  font-size: 18px;
  letter-spacing: 2px;
  line-height: 1.25;
  color: var(--navy);
}

.brand-text span {
  display: block;
  font-size: 10px;
  letter-spacing: 3px;
  color: var(--navy);
  text-transform: uppercase;
}

.nav { display: flex; align-items: center; gap: 26px; }

.nav a {
  position: relative;
  font-size: 15px;
  color: var(--text);
  padding: 4px 0;
  transition: color 0.2s;
}

.nav a::after {
  content: "";
  position: absolute;
  left: 0; right: 100%;
  bottom: 0;
  height: 1px;
  background: var(--blue);
  transition: right 0.28s ease;
}

.nav a:hover { color: var(--blue-dark); }
.nav a:hover::after { right: 0; }

.nav a.active { color: var(--blue-dark); }
.nav a.active::after { right: 0; }

.header-actions { display: flex; align-items: center; gap: 10px; }

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  height: 40px;
  padding: 0 20px;
  border-radius: 2px;
  border: 1px solid transparent;
  font-size: 14px;
  font-family: inherit;
  cursor: pointer;
  transition: all 0.2s;
  white-space: nowrap;
}

.btn-primary { background: var(--blue); color: #fff; }
.btn-primary:hover { background: var(--blue-dark); }

.btn-accent { background: var(--accent); color: #fff; }
.btn-accent:hover { background: var(--accent-dark); }

.btn-ghost { border-color: var(--line-strong); color: var(--text); background: #fff; }
.btn-ghost:hover { border-color: var(--blue-dark); color: var(--blue-dark); }

.btn-light { background: rgba(255,255,255,0.12); color: #fff; border: 1px solid rgba(255,255,255,0.35); }
.btn-light:hover { background: rgba(255,255,255,0.22); }

.btn:disabled { opacity: 0.55; cursor: not-allowed; }

.nav-toggle {
  display: none;
  width: 40px;
  height: 40px;
  border: 1px solid var(--line);
  border-radius: 2px;
  background: #fff;
  cursor: pointer;
  font-size: 18px;
  line-height: 1;
}

/* ---------- Hero ---------- */
.hero {
  position: relative;
  background: linear-gradient(180deg, #ffffff 0%, #f0f6fb 100%);
  border-bottom: 1px solid var(--blue-line);
  overflow: hidden;
}

.hero-split {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 64px;
  align-items: center;
  padding: 84px 24px 76px;
}

.hero-inner { max-width: 640px; padding: 0; }
.hero > .container:not(.hero-split) { padding: 84px 24px 76px; }

.hero-figure { position: relative; }
.hero-figure::after {
  content: "";
  position: absolute;
  inset: 14px -14px -14px 14px;
  border: 1px solid var(--blue-line);
  z-index: 0;
}

.hero-media {
  position: relative;
  z-index: 1;
  height: 360px;
  background-size: cover;
  background-position: center;
  filter: saturate(0.92);
}

.hero::after { display: none; }

.eyebrow {
  display: inline-block;
  font-size: 12px;
  letter-spacing: 2.4px;
  color: var(--blue-dark);
  text-transform: uppercase;
  border-bottom: 1px solid var(--blue-line);
  padding-bottom: 6px;
  margin-bottom: 26px;
}

h1.hero-title {
  margin: 0 0 22px;
  font-size: 46px;
  line-height: 1.32;
  letter-spacing: 1px;
  color: var(--navy);
}

.hero-desc {
  margin: 0 0 34px;
  font-size: 17px;
  color: var(--muted);
  max-width: 600px;
  line-height: 1.9;
}

.hero-actions { display: flex; gap: 14px; flex-wrap: wrap; }

.hero-stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  margin-top: 52px;
  padding-top: 24px;
  border-top: 1px solid var(--line);
}

.hero-stats div strong {
  display: block;
  font-family: var(--serif);
  font-size: 22px;
  font-weight: 600;
  color: var(--blue-dark);
  line-height: 1.4;
}

.hero-stats div span { font-size: 13px; color: var(--muted); }

/* 引言块 */
.lede-section { padding: 76px 0; background: var(--blue-soft); border-bottom: 1px solid var(--blue-line); }
.lede {
  font-family: var(--serif);
  font-size: 30px;
  line-height: 1.7;
  color: var(--navy);
  margin: 0 auto;
  max-width: 860px;
  text-align: center;
  letter-spacing: 0.5px;
}
.lede-by { text-align: center; color: var(--muted); font-size: 13px; margin: 18px 0 0; letter-spacing: 1px; }

/* ---------- Sections ---------- */
.section { padding: 92px 0; border-bottom: 1px solid var(--line); }
.section-soft { background: var(--bg-soft); }
.section:last-of-type { border-bottom: none; }

.section-head { max-width: 700px; margin-bottom: 52px; }

.section-tag {
  font-size: 12px;
  letter-spacing: 2.6px;
  color: var(--blue-dark);
  text-transform: uppercase;
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 12px;
}

.section-tag::after {
  content: "";
  flex: 1;
  height: 1px;
  background: var(--blue-line);
  max-width: 120px;
}

h2 {
  margin: 0 0 16px;
  font-size: 31px;
  line-height: 1.45;
  letter-spacing: 0.5px;
  color: var(--navy);
}

.section-head p { margin: 0; color: var(--muted); font-size: 16px; }

.center { text-align: center; }
.center .section-head { margin-left: auto; margin-right: auto; }
.center .section-tag { justify-content: center; }
.center .section-tag::after { display: none; }

/* cards */
.grid { display: grid; gap: 28px; }
.grid-4 { grid-template-columns: repeat(4, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }

.card {
  position: relative;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 30px 26px;
  transition: border-color 0.25s;
}

.card::before {
  content: "";
  position: absolute;
  left: -1px; top: -1px; bottom: -1px;
  width: 2px;
  background: var(--accent);
  transform: scaleY(0);
  transform-origin: top;
  transition: transform 0.32s ease;
}

.card:hover { border-color: var(--line-strong); }
.card:hover::before { transform: scaleY(1); }

.card-icon { display: none; }

.card h3 { margin: 0 0 12px; font-size: 19px; color: var(--navy); letter-spacing: 0.5px; }
.card p { margin: 0; color: var(--muted); font-size: 15px; }

/* steps */
.steps { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }

.step {
  padding: 24px 4px 0;
  border-top: 2px solid var(--blue-line);
}

.step-num {
  font-family: var(--serif);
  font-size: 15px;
  letter-spacing: 2px;
  color: var(--blue-dark);
  margin-bottom: 10px;
}

.step h4 { margin: 0 0 8px; font-size: 17px; font-family: var(--serif); color: var(--navy); }
.step p { margin: 0; font-size: 14px; color: var(--muted); }

/* split */
.split {
  display: grid;
  grid-template-columns: 1.02fr 1fr;
  gap: 64px;
  align-items: center;
}

.split img { border: 1px solid var(--line); filter: saturate(0.92); }

.list-check { list-style: none; padding: 0; margin: 24px 0 0; }

.list-check li {
  position: relative;
  padding-left: 24px;
  margin-bottom: 14px;
  color: var(--muted);
  font-size: 15px;
}

.list-check li::before {
  content: "—";
  position: absolute;
  left: 0;
  top: 0;
  color: var(--accent);
}

/* cta band */
.cta-band {
  background: var(--bg-soft);
  border: 1px solid var(--line);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
  padding: 46px 44px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
  flex-wrap: wrap;
}

.cta-band h2 { margin: 0 0 10px; color: var(--navy); font-size: 27px; }
.cta-band p { margin: 0; color: var(--muted); font-size: 15px; }

/* timeline */
.timeline { border-left: 1px solid var(--line-strong); padding-left: 30px; }

.timeline-item { position: relative; padding-bottom: 32px; }

.timeline-item::before {
  content: "";
  position: absolute;
  left: -35px;
  top: 10px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: #fff;
  border: 1px solid var(--blue);
}

.timeline-item strong {
  display: block;
  font-family: var(--serif);
  font-size: 18px;
  color: var(--navy);
  margin-bottom: 6px;
  font-weight: 600;
}
.timeline-item p { margin: 0; color: var(--muted); font-size: 15px; }

/* FAQ */
.faq-item {
  border-top: 1px solid var(--line);
  padding: 22px 4px 24px;
  transition: border-color 0.2s;
}

.faq-item:hover { border-top-color: var(--blue); }

.faq-item h4 {
  margin: 0 0 10px;
  font-size: 17px;
  font-family: var(--serif);
  color: var(--navy);
  font-weight: 600;
}

.faq-item p { margin: 0; color: var(--muted); font-size: 15px; }

/* ---------- Forms ---------- */
.form-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 18px; }

.field { display: flex; flex-direction: column; gap: 8px; }
.field-full { grid-column: 1 / -1; }

label { font-size: 14px; font-weight: 600; color: var(--text); }

input, select, textarea {
  width: 100%;
  padding: 11px 14px;
  border: 1px solid var(--line);
  border-radius: 2px;
  font-size: 15px;
  font-family: inherit;
  color: var(--text);
  background: #fff;
  transition: border-color 0.2s, box-shadow 0.2s;
}

input:focus, select:focus, textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}

textarea { min-height: 120px; resize: vertical; }

.hint { font-size: 13px; color: var(--muted); }
.field-error { font-size: 13px; color: #b4472f; min-height: 18px; }

.alert {
  padding: 12px 16px;
  border-radius: 2px;
  font-size: 14px;
  margin-bottom: 18px;
  display: none;
}

.alert.show { display: block; }
.alert-error { background: #fbf0ec; color: #a5452c; border: 1px solid #eecfbf; }
.alert-ok { background: var(--accent-soft); color: var(--accent-dark); border: 1px solid rgba(26, 143, 121, 0.32); }

.file-row { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; }
.file-row input[type="file"] { max-width: 320px; padding: 8px; }

/* ---------- Contact info ---------- */
.info-card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 28px 26px;
  height: 100%;
}

.info-list { list-style: none; margin: 0; padding: 0; }

.info-list li {
  display: flex;
  gap: 14px;
  padding: 13px 0;
  border-bottom: 1px solid var(--line);
  font-size: 15px;
}

.info-list li:last-child { border-bottom: none; }
.info-list .k { color: var(--muted); min-width: 74px; }
.info-list .v { color: var(--text); font-weight: 500; }

/* ---------- Member ---------- */
.member-panel {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 28px;
  align-items: start;
}

.member-card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 28px 24px;
  text-align: center;
}

.avatar {
  width: 92px;
  height: 92px;
  border-radius: 50%;
  margin: 0 auto 16px;
  background: var(--navy);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--serif);
  font-size: 30px;
  overflow: hidden;
}

.avatar img { width: 100%; height: 100%; object-fit: cover; }

.member-body {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 30px;
}

.msg-item {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px 18px;
  margin-bottom: 14px;
}

.msg-item .meta {
  display: flex;
  justify-content: space-between;
  font-size: 13px;
  color: var(--muted);
  margin-bottom: 8px;
  flex-wrap: wrap;
  gap: 8px;
}

.badge {
  font-size: 12px;
  padding: 2px 10px;
  border-radius: 999px;
  background: var(--blue-soft);
  color: var(--blue-dark);
}

/* ---------- Modal ---------- */
.modal-mask {
  position: fixed;
  inset: 0;
  background: rgba(14, 24, 33, 0.5);
  backdrop-filter: blur(3px);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 200;
  padding: 20px;
}

.modal-mask.show { display: flex; }

.modal {
  width: 100%;
  max-width: 420px;
  background: #fff;
  border-radius: 4px;
  padding: 32px;
  box-shadow: 0 24px 60px rgba(0, 0, 0, 0.22);
  max-height: 90vh;
  overflow-y: auto;
}

.modal h3 { margin: 0 0 6px; font-size: 22px; }
.modal .sub { margin: 0 0 22px; color: var(--muted); font-size: 14px; }

.tabs { display: flex; gap: 6px; background: var(--bg-soft); padding: 4px; border-radius: 2px; margin-bottom: 20px; }

.tabs button {
  flex: 1;
  height: 34px;
  border: none;
  background: transparent;
  border-radius: 2px;
  font-size: 14px;
  font-family: inherit;
  cursor: pointer;
  color: var(--muted);
}

.tabs button.active { background: #fff; color: var(--text); font-weight: 600; }

.code-row { display: flex; gap: 10px; }
.code-row input { flex: 1; }

.modal-foot { margin-top: 20px; font-size: 13px; color: var(--muted); text-align: center; }
.modal-close { float: right; margin: -8px -8px 0 0; border: none; background: none; font-size: 22px; cursor: pointer; color: var(--muted); }

/* ---------- Footer ---------- */
.site-footer {
  background: #fff;
  color: var(--muted);
  padding: 60px 0 26px;
  border-top: 1px solid var(--line);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.6fr 1fr 1fr 1fr;
  gap: 40px;
  padding-bottom: 34px;
  border-bottom: 1px solid var(--line);
}

.footer-grid h4 {
  color: var(--navy);
  font-family: var(--serif);
  font-size: 16px;
  font-weight: 600;
  margin: 0 0 18px;
  letter-spacing: 1px;
}
.footer-grid p { margin: 0 0 12px; font-size: 14px; }
.footer-grid ul { list-style: none; margin: 0; padding: 0; }
.footer-grid li { margin-bottom: 10px; font-size: 14px; }
.footer-grid li a:hover { color: var(--blue-dark); }

.footer-bottom {
  padding-top: 22px;
  display: flex;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
  font-size: 13px;
  color: #8a949d;
}

.footer-bottom a { text-decoration: underline; }
.footer-bottom a:hover { color: var(--blue-dark); }

.site-header.scrolled {
  box-shadow: 0 8px 28px rgba(18, 33, 46, 0.08);
}

/* 滚动显现（JS 渐进增强，无 JS 时不受影响） */
.reveal {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 0.65s ease, transform 0.65s ease;
}
.reveal-fast { transform: translateY(8px); transition-duration: 0.5s; }
.reveal.in { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal, .reveal-fast { opacity: 1; transform: none; transition: none; }
}

/* ---------- Responsive ---------- */
@media (max-width: 1000px) {
  .hero-split { grid-template-columns: 1fr; gap: 40px; padding: 64px 24px 56px; }
  .hero-media { height: 280px; }
  .hero-figure::after { display: none; }
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
  .steps { grid-template-columns: repeat(2, 1fr); }
  .split { grid-template-columns: 1fr; gap: 36px; }
  .member-panel { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 720px) {
  .nav-toggle { display: block; }

  .nav {
    position: absolute;
    top: 76px;
    left: 0;
    right: 0;
    background: #fff;
    border-bottom: 1px solid var(--line);
    flex-direction: column;
    align-items: stretch;
    padding: 12px 20px 20px;
    gap: 2px;
    display: none;
  }

  .nav.open { display: flex; }
  .nav a { padding: 12px 0; }
  .nav a::after { display: none; }
  .header-actions .btn { height: 36px; padding: 0 14px; font-size: 13px; }

  h1.hero-title { font-size: 33px; }
  .hero-stats { grid-template-columns: repeat(2, 1fr); }
  .section { padding: 62px 0; }
  h2 { font-size: 25px; }
  .lede { font-size: 22px; }
  .lede-section { padding: 54px 0; }
  .grid-4, .grid-3, .grid-2, .steps, .form-grid { grid-template-columns: 1fr; }
  .cta-band { padding: 32px 24px; }
  .footer-grid { grid-template-columns: 1fr; }
}