:root {
  color-scheme: light;
  --background: #f5f7fa;
  --surface: #ffffff;
  --surface-subtle: #eef2f6;
  --surface-muted: #f8fafc;
  --text: #111827;
  --text-muted: #475467;
  --text-soft: #667085;
  --border: #d0d5dd;
  --border-subtle: #e4e7ec;
  --primary: #0f766e;
  --primary-strong: #115e59;
  --focus: #1d4ed8;
  --max-width: 1180px;
  --content-width: 900px;
  font-family:
    "Noto Sans JP", "Hiragino Sans", "Yu Gothic", system-ui, -apple-system,
    BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--background);
  color: var(--text);
  font-size: 16px;
  line-height: 1.65;
  overflow-x: hidden;
}

a {
  color: var(--primary);
  text-decoration-thickness: 0.08em;
  text-underline-offset: 0.18em;
}

a:hover {
  color: var(--primary-strong);
}

a:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 3px;
}

p {
  margin: 0;
  color: var(--text-muted);
}

h1,
h2,
h3 {
  margin: 0;
  color: var(--text);
  line-height: 1.18;
  letter-spacing: 0;
}

h1 {
  max-width: 820px;
  font-size: 3.25rem;
}

h2 {
  font-size: 2.2rem;
}

h3 {
  font-size: 1.16rem;
}

img {
  display: block;
  max-width: 100%;
  height: auto;
}

.skip-link {
  position: absolute;
  left: 16px;
  top: 12px;
  z-index: 10;
  transform: translateY(-140%);
  border-radius: 8px;
  background: var(--text);
  color: #ffffff;
  padding: 10px 12px;
}

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

.site-shell {
  min-height: 100vh;
}

.topbar {
  border-bottom: 1px solid var(--border-subtle);
  background: rgba(255, 255, 255, 0.96);
}

.topbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 16px 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
  font-weight: 800;
  text-decoration: none;
}

.brand-mark {
  display: block;
  width: 34px;
  height: 34px;
  border-radius: 8px;
  box-shadow: 0 1px 2px rgba(17, 24, 39, 0.12);
}

.nav-links {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 6px;
}

.nav-links a {
  display: inline-flex;
  min-height: 40px;
  align-items: center;
  justify-content: center;
  border-radius: 8px;
  color: var(--text-muted);
  font-size: 0.92rem;
  font-weight: 700;
  padding: 8px 10px;
  text-decoration: none;
  white-space: nowrap;
}

.nav-links a:hover {
  background: var(--surface-subtle);
  color: var(--text);
}

.nav-links a.nav-login {
  margin-left: 6px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  padding-right: 13px;
  padding-left: 13px;
}

.nav-links a.nav-login:hover {
  border-color: var(--primary);
  background: var(--surface-subtle);
  color: var(--primary-strong);
}

.page-section {
  border-bottom: 1px solid var(--border-subtle);
}

.section-inner {
  display: grid;
  gap: 32px;
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 72px 24px;
}

.hero {
  background: var(--surface);
}

.hero-inner {
  display: grid;
  grid-template-columns: 1fr;
  gap: 30px;
  align-items: start;
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 54px 24px 64px;
}

.hero-copy,
.section-header {
  display: grid;
  gap: 14px;
  max-width: 780px;
}

.eyebrow,
.section-kicker,
.article-kicker {
  color: var(--primary-strong);
  font-size: 0.82rem;
  font-weight: 800;
}

.eyebrow {
  display: inline-flex;
  width: fit-content;
  max-width: 100%;
  align-items: center;
  border: 1px solid rgba(15, 118, 110, 0.26);
  border-radius: 999px;
  background: rgba(15, 118, 110, 0.08);
  padding: 6px 11px;
}

.lead {
  max-width: 700px;
  color: var(--text-muted);
  font-size: 1.12rem;
}

.hero-actions,
.section-actions,
.article-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.button-link {
  display: inline-flex;
  min-height: 46px;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--surface);
  color: var(--text);
  font-size: 0.95rem;
  font-weight: 800;
  padding: 10px 15px;
  text-decoration: none;
}

.button-link.primary {
  border-color: var(--primary);
  background: var(--primary);
  color: #ffffff;
}

.button-link.primary:hover {
  background: var(--primary-strong);
  color: #ffffff;
}

.button-link:hover {
  border-color: var(--primary);
  color: var(--primary-strong);
}

.hero-visual img,
.article-hero img {
  width: 100%;
  border: 1px solid var(--border-subtle);
  border-radius: 8px;
  background: #ffffff;
  box-shadow: 0 18px 48px rgba(17, 24, 39, 0.12);
}

.article-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
}

.article-card,
.note-panel {
  display: grid;
  gap: 14px;
  border: 1px solid var(--border-subtle);
  border-radius: 8px;
  background: var(--surface);
  padding: 22px;
}

.article-card {
  grid-template-columns: 1fr;
}

.article-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 12px;
  color: var(--text-soft);
  font-size: 0.88rem;
  font-weight: 700;
}

.article-card h3 {
  font-size: 1.45rem;
}

.article-link {
  width: fit-content;
  font-weight: 800;
  text-decoration: none;
}

.final-cta {
  background: var(--text);
  color: #ffffff;
}

.final-cta h2,
.final-cta p,
.final-cta .section-kicker {
  color: #ffffff;
}

.final-cta .button-link {
  border-color: rgba(255, 255, 255, 0.38);
  background: rgba(255, 255, 255, 0.08);
  color: #ffffff;
}

.final-cta .button-link.primary {
  border-color: #ffffff;
  background: #ffffff;
  color: var(--text);
}

.article-shell {
  background: var(--surface);
}

.article-header {
  display: grid;
  gap: 20px;
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 56px 24px 28px;
}

.article-body {
  display: grid;
  gap: 30px;
  max-width: 760px;
  margin: 0 auto;
  padding: 36px 24px 72px;
}

.article-body section {
  display: grid;
  gap: 12px;
}

.article-body p,
.article-body li {
  color: var(--text-muted);
  font-size: 1.03rem;
}

.article-body ul {
  display: grid;
  gap: 10px;
  margin: 0;
  padding-left: 1.2rem;
}

.article-body h2 {
  font-size: 1.7rem;
}

.note-panel {
  background: var(--surface-muted);
}

.footer {
  background: var(--surface);
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 28px 24px;
  color: var(--text-soft);
  font-size: 0.92rem;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}

.footer-links a {
  color: var(--text-muted);
  font-weight: 700;
  text-decoration: none;
}

@media (max-width: 960px) {
  .topbar-inner {
    align-items: flex-start;
    flex-direction: column;
  }

  .nav-links {
    width: 100%;
    justify-content: flex-start;
    overflow-x: auto;
    padding-bottom: 2px;
  }

  .nav-links a.nav-login {
    margin-left: auto;
  }

  h1 {
    font-size: 2.9rem;
  }

  h2 {
    font-size: 2rem;
  }
}

@media (max-width: 640px) {
  .topbar-inner {
    align-items: center;
    flex-direction: row;
    gap: 12px;
  }

  .brand {
    flex: 0 0 auto;
  }

  .nav-links {
    flex: 1 1 auto;
    justify-content: flex-start;
  }

  .nav-links a:not(.nav-login):nth-child(n + 3) {
    display: none;
  }

  .nav-links a.nav-login {
    flex: 0 0 auto;
  }

  .topbar-inner,
  .section-inner,
  .hero-inner,
  .article-header,
  .article-body,
  .footer-inner {
    padding-left: 16px;
    padding-right: 16px;
  }

  .hero-inner {
    gap: 24px;
    padding-top: 28px;
    padding-bottom: 42px;
  }

  .section-inner {
    padding-top: 52px;
    padding-bottom: 52px;
  }

  .article-header {
    padding-top: 36px;
  }

  h1 {
    font-size: 2.28rem;
  }

  h2 {
    font-size: 1.72rem;
  }

  .lead {
    font-size: 1.04rem;
  }

  .hero-visual img,
  .article-hero img {
    max-height: 156px;
    object-fit: cover;
    object-position: top center;
  }

  .hero-actions .button-link,
  .section-actions .button-link,
  .article-actions .button-link {
    width: 100%;
  }

  .footer-inner {
    align-items: flex-start;
    flex-direction: column;
  }
}

@media (max-width: 420px) {
  .nav-links a:not(.nav-login):nth-child(n + 2) {
    display: none;
  }
}