:root {
  --c-base: #FFFFFF;
  --c-soft: #ECF7F7;
  --c-accent: #0FB5B5;
  --c-accent-2: #0A9595;
  --c-accent-soft: #B6F1F4;
  --c-text: #1F2A2A;
  --c-text-sub: #67726F;
  --c-text-mute: #97A09D;
  --c-line: #E4ECEB;
  --c-line-soft: #EFF5F4;
  --f-jp: 'Noto Sans JP','Hiragino Sans','Yu Gothic',sans-serif;
  --f-en: 'Inter','Helvetica Neue',Helvetica,Arial,sans-serif;
  --f-display: 'Fraunces','Times New Roman',serif;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}
* { margin: 0; padding: 0; box-sizing: border-box; }
body {
  font-family: var(--f-jp);
  color: var(--c-text);
  background: var(--c-base);
  line-height: 1.95;
  font-size: 15px;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; display: block; }

/* Site Nav */
.site-nav {
  background: rgba(255,255,255,0.92);
  border-bottom: 1px solid var(--c-line);
  padding: 16px 24px;
  display: flex; align-items: center; justify-content: space-between;
  position: sticky; top: 0; z-index: 60;
  backdrop-filter: blur(8px);
}
.site-nav .brand {
  font-family: var(--f-display); font-size: 22px; font-weight: 500;
  color: var(--c-text); text-decoration: none; letter-spacing: 0.02em;
  display: flex; align-items: center; gap: 10px;
}
.site-nav .brand .mark {
  width: 28px; height: 28px; border-radius: 50%;
  background: var(--c-accent); color: #fff;
  display: inline-flex; align-items: center; justify-content: center;
  font-family: var(--f-en); font-size: 14px; font-weight: 500;
}
.site-nav .nav-back {
  font-family: var(--f-en); font-size: 12px; letter-spacing: 0.16em; text-transform: uppercase;
  color: var(--c-text-sub); text-decoration: none;
}
.site-nav .nav-back:hover { color: var(--c-accent); }

/* Article header */
.article-header {
  padding: 80px 24px 56px;
  background: linear-gradient(160deg, var(--c-soft) 0%, var(--c-base) 100%);
  border-bottom: 1px solid var(--c-line);
  text-align: center;
}
.breadcrumb {
  font-family: var(--f-en); font-size: 11px; letter-spacing: 0.16em;
  color: var(--c-text-mute); text-transform: uppercase;
  margin-bottom: 18px;
}
.breadcrumb a { color: var(--c-text-mute); text-decoration: none; }
.breadcrumb a:hover { color: var(--c-accent); }
.article-meta {
  display: inline-flex; gap: 14px; align-items: center;
  margin-bottom: 22px;
}
.article-meta .cat {
  font-family: var(--f-en); font-size: 11px; letter-spacing: 0.22em;
  color: var(--c-accent); text-transform: uppercase;
  padding: 4px 12px; background: rgba(15,181,181,0.08); border-radius: 999px;
}
.article-meta .date {
  font-family: var(--f-en); font-size: 13px; color: var(--c-text-sub);
}
.article-title {
  font-family: var(--f-display);
  font-size: clamp(24px, 4vw, 38px); font-weight: 400;
  line-height: 1.4;
  max-width: 760px; margin: 0 auto;
  letter-spacing: 0.02em;
}

/* Eyecatch */
.article-eyecatch {
  width: 100%;
  max-width: 1200px;
  margin: 48px auto 0;
  aspect-ratio: 16/9;
  background-size: cover; background-position: center;
}

/* Article body */
.article-body {
  max-width: 720px;
  margin: 0 auto;
  padding: 56px 24px 80px;
}
.article-body h2 {
  font-family: var(--f-display);
  font-size: 22px; font-weight: 500;
  margin-top: 48px; margin-bottom: 18px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--c-line);
}
.article-body h2:first-child { margin-top: 0; }
.article-body h3 {
  font-family: var(--f-display);
  font-size: 17px; font-weight: 500;
  margin-top: 32px; margin-bottom: 12px;
}
.article-body p { margin-bottom: 24px; }
.article-body ul, .article-body ol {
  margin-bottom: 24px;
  padding-left: 24px;
}
.article-body li { margin-bottom: 8px; line-height: 1.85; }
.article-body a {
  color: var(--c-accent);
  border-bottom: 1px solid var(--c-accent);
  text-decoration: none;
  transition: color .2s var(--ease), border-color .2s var(--ease);
}
.article-body a:hover { color: var(--c-accent-2); border-color: var(--c-accent-2); }
.article-body strong {
  font-weight: 500; color: var(--c-text);
  background: rgba(15,181,181,0.08);
  padding: 1px 4px;
}
.article-body img {
  margin: 32px 0;
  border-radius: 4px;
}
.article-body blockquote {
  border-left: 3px solid var(--c-accent);
  padding: 12px 24px;
  margin: 32px 0;
  background: var(--c-soft);
  font-size: 14px;
  line-height: 1.85;
  color: var(--c-text-sub);
}
.article-body code {
  background: var(--c-soft);
  padding: 2px 6px;
  font-family: 'SF Mono','Consolas',monospace;
  font-size: 13px;
}

/* CTA section */
.cta-section {
  background: linear-gradient(160deg, #0F2A2A 0%, var(--c-accent-2) 100%);
  color: #fff;
  padding: 64px 24px;
  text-align: center;
}
.cta-section h2 {
  font-family: var(--f-display);
  font-size: clamp(22px, 3vw, 30px);
  font-weight: 400;
  margin-bottom: 14px;
}
.cta-section p {
  opacity: 0.85;
  max-width: 540px; margin: 0 auto 28px;
  font-size: 14px; line-height: 1.85;
}
.cta-buttons {
  display: inline-flex; gap: 12px; flex-wrap: wrap; justify-content: center;
}
.btn-cta, .btn-ghost {
  display: inline-flex; align-items: center; gap: 10px;
  padding: 16px 32px;
  font-family: var(--f-en); font-size: 13px; letter-spacing: 0.06em;
  font-weight: 500; text-decoration: none;
  border-radius: 4px;
  transition: background 0.2s, color 0.2s, border-color 0.2s, transform 0.2s;
}
.btn-cta {
  background: var(--c-accent); color: #fff; border: 1px solid var(--c-accent);
  box-shadow: 0 4px 20px rgba(15,181,181,0.25);
}
.btn-cta:hover { background: var(--c-accent-2); border-color: var(--c-accent-2); transform: translateY(-1px); }
.btn-ghost {
  background: transparent; color: #fff; border: 1px solid rgba(255,255,255,0.6);
}
.btn-ghost:hover { background: rgba(255,255,255,0.1); border-color: #fff; }

/* Other news */
.other-news {
  max-width: 800px; margin: 0 auto;
  padding: 56px 24px;
  border-top: 1px solid var(--c-line);
}
.other-news h2 {
  font-family: var(--f-en); font-size: 11px; letter-spacing: 0.22em;
  color: var(--c-text-sub); text-transform: uppercase;
  margin-bottom: 24px; text-align: center; font-weight: 500;
}
.other-news .news-item {
  display: grid; grid-template-columns: 100px 1fr; gap: 20px;
  padding: 16px 0; border-bottom: 1px solid var(--c-line-soft);
  text-decoration: none; color: inherit;
  transition: padding-left .2s ease;
  align-items: start;
}
.other-news .news-item:hover { padding-left: 8px; }
.other-news .news-item:hover .title { color: var(--c-accent); }
.other-news .date { font-family: var(--f-en); font-size: 12px; color: var(--c-text-sub); padding-top: 2px; }
.other-news .body { display: flex; flex-direction: column; gap: 4px; }
.other-news .cat { font-family: var(--f-en); font-size: 10px; letter-spacing: 0.18em; color: var(--c-accent); text-transform: uppercase; }
.other-news .title { font-size: 14px; line-height: 1.7; transition: color .2s ease; }

/* Footer */
.site-footer {
  text-align: center; padding: 32px 20px;
  font-family: var(--f-en); font-size: 11px; letter-spacing: 0.16em;
  color: var(--c-text-mute); border-top: 1px solid var(--c-line);
  background: var(--c-base);
}

/* Mobile */
@media (max-width: 600px) {
  .site-nav { padding: 14px 18px; }
  .site-nav .brand { font-size: 18px; }
  .site-nav .brand .mark { width: 24px; height: 24px; font-size: 12px; }
  .site-nav .nav-back .nav-back-label { display: none; }
  .site-nav .nav-back::after { content: "HOME"; margin-left: 4px; }
  .article-header { padding: 56px 18px 40px; }
  .article-title { font-size: clamp(22px, 6vw, 28px); }
  .article-body { padding: 40px 18px 64px; }
  .article-body h2 { font-size: 19px; margin-top: 36px; }
  .article-body h3 { font-size: 16px; }
  .other-news .news-item { grid-template-columns: 80px 1fr; gap: 14px; }
  .cta-section { padding: 48px 20px; }
  .cta-buttons { flex-direction: column; align-items: stretch; }
  .cta-buttons a { justify-content: center; }
}