:root {
  color-scheme: light;
  --ink: #172033;
  --muted: #5c6678;
  --navy: #10182b;
  --navy-soft: #192540;
  --blue: #245eea;
  --blue-dark: #1948bb;
  --line: #dfe5ee;
  --surface: #ffffff;
  --surface-soft: #f5f7fb;
  --success: #137a55;
  --content-width: 72rem;
  --article-width: 46rem;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--surface-soft);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans TC", sans-serif;
  font-size: 1rem;
  line-height: 1.75;
}

a {
  color: var(--blue-dark);
  text-underline-offset: 0.2em;
}

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

.skip-link {
  position: absolute;
  top: 0.5rem;
  left: 0.5rem;
  z-index: 20;
  transform: translateY(-160%);
  border-radius: 0.5rem;
  background: #ffffff;
  padding: 0.75rem 1rem;
  font-weight: 700;
}

.skip-link:focus {
  transform: translateY(0);
}

.site-header {
  background: var(--navy);
  color: #ffffff;
}

.header-inner,
.shell {
  width: min(100% - 2rem, var(--content-width));
  margin-inline: auto;
}

.header-inner {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  padding-block: 1rem;
}

.brand-link {
  color: #ffffff;
  font-size: 1.05rem;
  font-weight: 800;
  text-decoration: none;
}

.site-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.site-nav a {
  display: inline-flex;
  min-height: 2.75rem;
  align-items: center;
  border-radius: 0.6rem;
  color: #dbe7ff;
  padding-inline: 0.9rem;
  text-decoration: none;
}

.site-nav a:hover,
.site-nav a:focus-visible {
  background: var(--navy-soft);
  color: #ffffff;
}

.hero {
  background: linear-gradient(135deg, var(--navy) 0%, var(--navy-soft) 62%, #21345c 100%);
  color: #ffffff;
  padding-block: 3.5rem;
}

.hero-copy {
  max-width: 52rem;
}

.eyebrow {
  margin: 0 0 0.75rem;
  color: #9fbaff;
  font-size: 0.875rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.hero h1,
.article-header h1 {
  margin: 0;
  font-size: clamp(2rem, 7vw, 3.5rem);
  line-height: 1.2;
}

.hero p {
  max-width: 42rem;
  margin: 1rem 0 0;
  color: #c7d3e8;
  font-size: 1.05rem;
}

.button-row {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  margin-top: 1.5rem;
}

.button {
  display: inline-flex;
  min-height: 2.75rem;
  align-items: center;
  justify-content: center;
  border-radius: 0.7rem;
  background: var(--blue);
  color: #ffffff;
  padding: 0.75rem 1.1rem;
  font-weight: 800;
  text-decoration: none;
}

.button:hover,
.button:focus-visible {
  background: #ffffff;
  color: var(--navy);
}

.button-secondary {
  border: 1px solid #7083a6;
  background: transparent;
}

.content-section {
  padding-block: 2.5rem 4rem;
}

.section-heading {
  margin: 0 0 1.25rem;
  font-size: clamp(1.6rem, 4vw, 2.2rem);
  line-height: 1.3;
}

.article-card {
  display: block;
  border: 1px solid var(--line);
  border-radius: 1rem;
  background: var(--surface);
  color: inherit;
  padding: 1.25rem;
  text-decoration: none;
  box-shadow: 0 0.8rem 2rem rgba(26, 39, 67, 0.06);
}

.article-card:hover,
.article-card:focus-visible {
  border-color: #9db6f6;
  color: inherit;
  box-shadow: 0 1rem 2.5rem rgba(26, 39, 67, 0.11);
}

.article-card h2 {
  margin: 0.35rem 0 0.6rem;
  font-size: clamp(1.25rem, 4vw, 1.65rem);
  line-height: 1.4;
}

.article-card p {
  margin: 0;
  color: var(--muted);
}

.meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1rem;
  color: var(--muted);
  font-size: 0.875rem;
}

.tag {
  display: inline-flex;
  align-items: center;
  border-radius: 999px;
  background: #e9efff;
  color: #234aab;
  padding: 0.2rem 0.65rem;
  font-size: 0.875rem;
  font-weight: 800;
}

.breadcrumbs {
  padding-block: 1rem;
  color: var(--muted);
  font-size: 0.875rem;
}

.breadcrumbs ol {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.article-shell {
  width: min(100% - 2rem, var(--article-width));
  margin-inline: auto;
}

.article-header {
  padding-block: 1rem 2rem;
}

.article-header h1 {
  font-size: clamp(1.9rem, 6vw, 3.1rem);
}

.article-header .summary {
  margin: 1rem 0 0;
  color: var(--muted);
  font-size: 1.05rem;
}

.answer-box {
  border-left: 0.3rem solid var(--blue);
  border-radius: 0.75rem;
  background: #edf3ff;
  margin: 0 0 2rem;
  padding: 1rem 1.1rem;
}

.answer-box strong {
  display: block;
  margin-bottom: 0.35rem;
}

.article-body {
  border: 1px solid var(--line);
  border-radius: 1rem;
  background: var(--surface);
  padding: 1.25rem;
  box-shadow: 0 0.8rem 2rem rgba(26, 39, 67, 0.05);
}

.article-body h2 {
  margin: 2.5rem 0 0.8rem;
  font-size: clamp(1.4rem, 4vw, 1.8rem);
  line-height: 1.35;
}

.article-body h2:first-child {
  margin-top: 0;
}

.article-body h3 {
  margin: 1.8rem 0 0.55rem;
  font-size: 1.2rem;
  line-height: 1.45;
}

.article-body p,
.article-body ul,
.article-body ol {
  margin-block: 0 1rem;
}

.article-body ul,
.article-body ol {
  padding-left: 1.4rem;
}

.article-body li + li {
  margin-top: 0.45rem;
}

.article-cta {
  border-radius: 1rem;
  background: var(--navy);
  color: #ffffff;
  margin-top: 2rem;
  padding: 1.25rem;
}

.article-cta h2 {
  margin: 0 0 0.5rem;
  font-size: 1.35rem;
}

.article-cta p {
  margin: 0;
  color: #c7d3e8;
}

.site-footer {
  border-top: 1px solid var(--line);
  background: #ffffff;
  color: var(--muted);
  padding-block: 2rem;
}

.site-footer p {
  margin: 0;
}

@media (min-width: 40rem) {
  .header-inner {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
  }

  .button-row {
    flex-direction: row;
  }

  .article-card,
  .article-body,
  .article-cta {
    padding: 1.75rem;
  }
}

@media (min-width: 64rem) {
  .hero {
    padding-block: 5rem;
  }

  .content-section {
    padding-block: 4rem 5rem;
  }
}

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