:root {
  --ink: #102529;
  --muted: #5b7074;
  --paper: #f5fbfb;
  --panel: #ffffff;
  --line: #c9dcdd;
  --teal: #137d76;
  --teal-dark: #0d5e59;
  --lime: #a3e635;
  --amber: #a85b12;
  --amber-bg: #fff4df;
  --max-width: 1120px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: "Microsoft YaHei", "PingFang SC", "Noto Sans CJK SC", sans-serif;
  line-height: 1.7;
}

a {
  color: inherit;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  width: 100%;
  padding: 18px max(24px, calc((100vw - var(--max-width)) / 2));
  border-bottom: 1px solid rgba(201, 220, 221, 0.9);
  background: rgba(245, 251, 251, 0.96);
  backdrop-filter: blur(12px);
}

.brand {
  font-weight: 800;
  text-decoration: none;
}

nav {
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
  color: var(--muted);
  font-size: 14px;
}

nav a {
  text-decoration: none;
}

nav a:hover,
nav a:focus-visible {
  color: var(--teal-dark);
  text-decoration: underline;
  text-underline-offset: 4px;
}

.hero {
  width: min(calc(100% - 48px), var(--max-width));
  margin: 0 auto;
  padding: 96px 0 72px;
}

.eyebrow {
  margin: 0 0 12px;
  color: var(--teal-dark);
  font-size: 14px;
  font-weight: 800;
  letter-spacing: 0;
  text-transform: uppercase;
}

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

h1 {
  max-width: 880px;
  margin: 0;
  font-size: clamp(44px, 8vw, 88px);
  line-height: 1.04;
  letter-spacing: 0;
}

h2 {
  margin: 0;
  font-size: clamp(30px, 5vw, 52px);
  line-height: 1.15;
  letter-spacing: 0;
}

h3 {
  margin: 0;
  font-size: 21px;
  line-height: 1.35;
}

.hero-copy {
  max-width: 760px;
  margin: 28px 0 0;
  color: var(--muted);
  font-size: clamp(18px, 2.2vw, 23px);
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 50px;
  margin-top: 34px;
  padding: 0 24px;
  border: 2px solid var(--ink);
  border-radius: 8px;
  color: #fff;
  background: var(--ink);
  font-weight: 800;
  text-decoration: none;
}

.button:hover,
.button:focus-visible {
  border-color: var(--teal-dark);
  background: var(--teal-dark);
}

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

.visual-band {
  display: flex;
  justify-content: center;
  padding: 0 24px 72px;
  background: var(--paper);
}

.visual-band img {
  display: block;
  width: min(100%, 720px);
  height: auto;
  border: 1px solid var(--line);
  border-radius: 8px;
}

.content-section {
  padding: 88px max(24px, calc((100vw - var(--max-width)) / 2));
  background: var(--panel);
}

.content-section.alt {
  background: #e8f3f3;
}

.section-heading {
  max-width: 760px;
  margin-bottom: 42px;
}

.section-heading > p:last-child {
  margin: 18px 0 0;
  color: var(--muted);
  font-size: 18px;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 16px;
}

.info-card {
  min-height: 250px;
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
}

.card-number {
  display: block;
  margin-bottom: 34px;
  color: var(--teal);
  font-size: 14px;
  font-weight: 800;
}

.info-card p {
  margin: 14px 0 0;
  color: var(--muted);
}

.step-list {
  display: grid;
  gap: 12px;
  margin: 0;
  padding-left: 26px;
}

.step-list li {
  padding: 18px 20px 18px 8px;
  border-bottom: 1px solid var(--line);
}

.step-list strong,
.step-list span {
  display: block;
}

.step-list span {
  margin-top: 4px;
  color: var(--muted);
}

.warning-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.warning-list p {
  margin: 0;
  padding: 20px;
  border-left: 5px solid var(--amber);
  border-radius: 4px;
  background: var(--amber-bg);
}

.boundary-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.boundary-item {
  padding: 26px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
}

.boundary-item p {
  margin: 12px 0 0;
  color: var(--muted);
}

.site-footer {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 12px 24px;
  padding: 34px max(24px, calc((100vw - var(--max-width)) / 2));
  border-top: 1px solid var(--line);
  color: var(--muted);
  background: var(--paper);
  font-size: 14px;
}

.site-footer p {
  margin: 0;
}

.simple-page {
  width: min(calc(100% - 48px), 820px);
  margin: 0 auto;
  padding: 72px 0 96px;
}

.simple-page h1 {
  font-size: clamp(38px, 7vw, 64px);
}

.simple-page h2 {
  margin-top: 48px;
  font-size: 28px;
}

.simple-page p,
.simple-page li {
  color: var(--muted);
}

.back-link {
  display: inline-block;
  margin-bottom: 36px;
  color: var(--teal-dark);
  font-weight: 800;
  text-decoration: none;
}

@media (max-width: 900px) {
  .card-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 640px) {
  .site-header {
    position: static;
    align-items: flex-start;
    flex-direction: column;
  }

  nav {
    gap: 12px;
  }

  .hero {
    padding: 64px 0 52px;
  }

  .content-section {
    padding-top: 64px;
    padding-bottom: 64px;
  }

  .card-grid,
  .warning-list,
  .boundary-grid {
    grid-template-columns: 1fr;
  }

  .info-card {
    min-height: 0;
  }
}