:root {
  --bg: #f6f8fb;
  --surface: #ffffff;
  --text: #111827;
  --muted: #5f6b7a;
  --line: #dce3ec;
  --blue: #1d63ff;
  --blue-dark: #0b46c9;
  --green: #15a36b;
  --ink: #0b0f19;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: Arial, "Microsoft YaHei", "PingFang SC", sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.65;
}

a {
  color: var(--blue);
  text-decoration: none;
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  min-height: 72px;
  padding: 0 6vw;
  background: rgba(255, 255, 255, 0.94);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(12px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  font-weight: 700;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 38px;
  height: 38px;
  border-radius: 8px;
  color: #fff;
  background: var(--blue);
  font-size: 15px;
}

.nav {
  display: flex;
  gap: 22px;
  font-size: 15px;
}

.nav a {
  color: #263244;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.03fr) minmax(360px, 0.97fr);
  align-items: center;
  gap: 42px;
  padding: 78px 6vw 42px;
  background: linear-gradient(180deg, #edf4ff 0%, #f6f8fb 100%);
}

.hero-copy {
  max-width: 780px;
}

.eyebrow,
.section-kicker {
  margin: 0 0 10px;
  color: var(--green);
  font-size: 14px;
  font-weight: 700;
}

h1,
h2,
h3,
p {
  overflow-wrap: anywhere;
}

h1 {
  margin: 0;
  color: var(--ink);
  font-size: clamp(38px, 5vw, 68px);
  line-height: 1.06;
  letter-spacing: 0;
}

h2 {
  margin: 0 0 14px;
  color: var(--ink);
  font-size: 30px;
  line-height: 1.25;
}

h3 {
  margin: 0 0 8px;
  color: var(--ink);
  font-size: 18px;
  line-height: 1.35;
}

.lead {
  max-width: 680px;
  margin: 24px 0 0;
  color: #354153;
  font-size: 20px;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 30px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 0 20px;
  border: 1px solid #b9c5d4;
  border-radius: 8px;
  color: var(--ink);
  background: #fff;
  font-weight: 700;
}

.button.primary {
  border-color: var(--blue);
  color: #fff;
  background: var(--blue);
}

.notice {
  margin: 18px 0 0;
  color: var(--muted);
  font-size: 14px;
}

.hero-visual {
  margin: 0;
}

.hero-visual img {
  display: block;
  width: 100%;
  height: auto;
}

.quick-panel {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1px;
  margin: 0 6vw;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--line);
}

.quick-panel div {
  padding: 22px;
  background: var(--surface);
}

.quick-panel strong,
.quick-panel span {
  display: block;
}

.quick-panel strong {
  color: var(--muted);
  font-size: 14px;
}

.quick-panel span {
  margin-top: 6px;
  color: var(--ink);
  font-size: 18px;
  font-weight: 700;
}

.section {
  padding: 76px 6vw 0;
}

.seo-intro {
  display: grid;
  grid-template-columns: 280px minmax(0, 1fr);
  gap: 44px;
  align-items: start;
}

.toc {
  position: sticky;
  top: 96px;
  display: grid;
  gap: 8px;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.toc a {
  padding: 8px 0;
  border-top: 1px solid #edf1f6;
  color: #263244;
  font-weight: 700;
}

.two-col {
  display: grid;
  grid-template-columns: minmax(0, 0.8fr) minmax(0, 1.2fr);
  gap: 44px;
}

.two-col p,
.content-grid p,
.faq p {
  color: var(--muted);
}

.check-list,
.steps,
.content-grid {
  display: grid;
  gap: 18px;
}

.check-list {
  grid-template-columns: repeat(3, 1fr);
}

.check-list article,
.steps article,
.content-grid article {
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.steps {
  grid-template-columns: repeat(4, 1fr);
}

.steps span {
  display: grid;
  place-items: center;
  width: 36px;
  height: 36px;
  margin-bottom: 18px;
  border-radius: 8px;
  color: #fff;
  background: var(--blue);
  font-weight: 700;
}

.content-grid {
  grid-template-columns: repeat(3, 1fr);
}

.table-wrap {
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

table {
  width: 100%;
  min-width: 720px;
  border-collapse: collapse;
}

th,
td {
  padding: 18px;
  border-bottom: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

th {
  color: var(--ink);
  background: #eef4ff;
}

td {
  color: var(--muted);
}

tr:last-child td {
  border-bottom: 0;
}

.warning-section {
  margin: 76px 6vw 0;
  padding: 28px;
  border: 1px solid #ffd4a8;
  border-radius: 8px;
  background: #fff8ed;
}

.warning-section p {
  margin-bottom: 0;
  color: #6f4b13;
}

.faq {
  padding-bottom: 76px;
}

details {
  border-top: 1px solid var(--line);
  background: transparent;
}

details:last-child {
  border-bottom: 1px solid var(--line);
}

summary {
  cursor: pointer;
  padding: 20px 0;
  color: var(--ink);
  font-weight: 700;
}

details p {
  margin: 0;
  padding: 0 0 20px;
}

.footer {
  padding: 28px 6vw;
  color: #c9d4e5;
  background: var(--ink);
  font-size: 14px;
}

.footer p {
  margin: 6px 0;
}

.footer a {
  color: #91b4ff;
}

@media (max-width: 980px) {
  .site-header {
    align-items: flex-start;
    flex-direction: column;
    padding-top: 16px;
    padding-bottom: 16px;
  }

  .nav {
    width: 100%;
    overflow-x: auto;
    padding-bottom: 2px;
    white-space: nowrap;
  }

  .hero,
  .two-col {
    grid-template-columns: 1fr;
  }

  .hero {
    padding-top: 52px;
  }

  .quick-panel,
  .seo-intro,
  .check-list,
  .steps,
  .content-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .toc {
    position: static;
  }
}

@media (max-width: 640px) {
  .site-header,
  .hero,
  .section,
  .footer {
    padding-left: 20px;
    padding-right: 20px;
  }

  .quick-panel {
    margin-left: 20px;
    margin-right: 20px;
  }

  h1 {
    font-size: 38px;
  }

  h2 {
    font-size: 25px;
  }

  .lead {
    font-size: 17px;
  }

  .actions,
  .button {
    width: 100%;
  }

  .quick-panel,
  .seo-intro,
  .check-list,
  .steps,
  .content-grid {
    grid-template-columns: 1fr;
  }

  .warning-section {
    margin-left: 20px;
    margin-right: 20px;
  }
}