:root {
  --c-primary: #0c4a6e;
  --c-primary-light: #0369a1;
  --c-accent: #0ea5e9;
  --c-accent2: #38bdf8;
  --c-bg: #f8fafc;
  --c-white: #fff;
  --c-text: #1e293b;
  --c-text-light: #64748b;
  --c-border: #e2e8f0;
  --c-card: #fff;
  --shadow: 0 1px 3px rgba(0,0,0,.08), 0 4px 14px rgba(0,0,0,.04);
  --shadow-lg: 0 4px 24px rgba(0,0,0,.1);
  --radius: 12px;
  --radius-sm: 8px;
  --font: "Hiragino Sans", "Noto Sans JP", "Yu Gothic UI", "Meiryo", sans-serif;
  --max-w: 1120px;
  --header-h: 64px;
}

*, *::before, *::after { margin:0; padding:0; box-sizing:border-box; }

html { scroll-behavior:smooth; font-size:16px; }
body {
  font-family: var(--font);
  color: var(--c-text);
  background: var(--c-bg);
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--c-primary-light); text-decoration:none; transition: color .2s; }
a:hover { color: var(--c-accent); }
img { max-width:100%; height:auto; display:block; }
ul, ol { list-style:none; }

/* ---- HEADER ---- */
.site-header {
  position: sticky; top:0; z-index:100;
  background: linear-gradient(135deg, var(--c-primary) 0%, #0f4c75 100%);
  box-shadow: 0 2px 12px rgba(0,0,0,.15);
}
.header-inner {
  max-width: var(--max-w); margin:0 auto;
  display:flex; align-items:center; justify-content:space-between;
  padding: 0 20px; height: var(--header-h);
}
.logo {
  display:flex; align-items:center; gap:8px;
  color:#fff; font-size:1.2rem; font-weight:700;
}
.logo:hover { color:#e0f2fe; }
.logo-icon { font-size:1.5rem; }
.hamburger {
  display:none; background:none; border:none; cursor:pointer; padding:6px;
  flex-direction:column; gap:5px;
}
.hamburger span {
  display:block; width:24px; height:2px; background:#fff;
  transition: transform .3s, opacity .3s;
  border-radius:2px;
}
.hamburger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.hamburger.open span:nth-child(2) { opacity:0; }
.hamburger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

.global-nav { display:flex; gap:4px; }
.nav-link {
  color:rgba(255,255,255,.85); font-size:.85rem; padding:6px 12px;
  border-radius:6px; transition: background .2s, color .2s;
  white-space:nowrap;
}
.nav-link:hover, .nav-link.active { background:rgba(255,255,255,.15); color:#fff; }

@media (max-width:768px) {
  .hamburger { display:flex; }
  .global-nav {
    display:none; position:absolute; top:var(--header-h); left:0; right:0;
    background:var(--c-primary); flex-direction:column; padding:12px 20px;
    box-shadow: var(--shadow-lg);
  }
  .global-nav.open { display:flex; }
  .nav-link { padding:10px 0; border-bottom:1px solid rgba(255,255,255,.1); }
}

/* ---- HERO ---- */
.hero {
  background: linear-gradient(135deg, #0c4a6e 0%, #0284c7 50%, #0ea5e9 100%);
  color:#fff; padding:60px 20px 70px; text-align:center;
  position:relative; overflow:hidden;
}
.hero::before {
  content:''; position:absolute; top:-40%; right:-20%; width:60%; height:180%;
  background:radial-gradient(circle, rgba(56,189,248,.2) 0%, transparent 60%);
  pointer-events:none;
}
.hero::after {
  content:''; position:absolute; bottom:-30%; left:-10%; width:50%; height:120%;
  background:radial-gradient(circle, rgba(14,165,233,.15) 0%, transparent 55%);
  pointer-events:none;
}
.hero-inner { max-width:var(--max-w); margin:0 auto; position:relative; z-index:1; }
.hero h1 { font-size:2rem; margin-bottom:16px; font-weight:800; line-height:1.3; }
.hero .hero-sub { font-size:1.05rem; opacity:.9; margin-bottom:28px; line-height:1.6; }
.hero-cta {
  display:inline-flex; align-items:center; gap:8px;
  background:#fff; color:var(--c-primary); font-weight:700;
  padding:14px 32px; border-radius:50px; font-size:1rem;
  box-shadow: var(--shadow-lg); transition: transform .2s, box-shadow .2s;
}
.hero-cta:hover { transform:translateY(-2px); box-shadow: 0 6px 24px rgba(0,0,0,.2); color:var(--c-primary); }

/* ---- CONTAINER ---- */
.container { max-width:var(--max-w); margin:0 auto; padding:0 20px; }

/* ---- SECTION ---- */
.section { padding:50px 0; }
.section-title {
  font-size:1.5rem; font-weight:800; text-align:center;
  margin-bottom:8px; color:var(--c-primary);
}
.section-subtitle {
  text-align:center; color:var(--c-text-light); font-size:.95rem; margin-bottom:32px;
}

/* ---- CATEGORY GRID (top page) ---- */
.cat-grid {
  display:grid; grid-template-columns:repeat(auto-fill, minmax(260px,1fr)); gap:20px;
}
.cat-card {
  background:var(--c-card); border-radius:var(--radius); padding:24px;
  box-shadow:var(--shadow); transition: transform .2s, box-shadow .2s;
  border-left:4px solid var(--c-accent); position:relative; overflow:hidden;
}
.cat-card:hover { transform:translateY(-3px); box-shadow:var(--shadow-lg); }
.cat-card-icon { font-size:2rem; margin-bottom:8px; }
.cat-card h2 { font-size:1.1rem; margin-bottom:4px; }
.cat-card .cat-count { color:var(--c-text-light); font-size:.85rem; }
.cat-card::after {
  content:'\2192'; position:absolute; right:20px; top:50%; transform:translateY(-50%);
  font-size:1.4rem; color:var(--c-text-light); transition: transform .2s;
}
.cat-card:hover::after { transform: translateY(-50%) translateX(4px); }

/* ---- ARTICLE CARDS ---- */
.article-grid {
  display:grid; grid-template-columns:repeat(auto-fill, minmax(320px,1fr)); gap:24px;
}
.article-card {
  background:var(--c-card); border-radius:var(--radius); overflow:hidden;
  box-shadow:var(--shadow); transition: transform .2s, box-shadow .2s;
  display:flex; flex-direction:column;
}
.article-card:hover { transform:translateY(-3px); box-shadow:var(--shadow-lg); }
.article-card-body { padding:20px; flex:1; display:flex; flex-direction:column; }
.article-card .card-category {
  display:inline-block; font-size:.75rem; font-weight:600;
  padding:3px 10px; border-radius:20px; margin-bottom:10px;
  color:#fff; width:fit-content;
}
.article-card h3 {
  font-size:1rem; line-height:1.5; margin-bottom:8px;
  flex:1;
}
.article-card h3 a { color:var(--c-text); }
.article-card h3 a:hover { color:var(--c-primary-light); }
.article-card .card-meta {
  font-size:.8rem; color:var(--c-text-light); margin-top:auto;
}

/* ---- ARTICLE PAGE ---- */
.article-layout {
  display:grid; grid-template-columns:1fr 300px; gap:40px;
  max-width:var(--max-w); margin:0 auto; padding:40px 20px;
}
.article-main {}
.article-sidebar {}

.breadcrumb {
  font-size:.8rem; color:var(--c-text-light); margin-bottom:16px;
  display:flex; flex-wrap:wrap; align-items:center; gap:4px;
}
.breadcrumb a { color:var(--c-text-light); }
.breadcrumb a:hover { color:var(--c-primary-light); }
.breadcrumb .sep { color:var(--c-border); }

.article-header {
  margin-bottom:32px; padding-bottom:24px;
  border-bottom:1px solid var(--c-border);
}
.article-tag {
  display:inline-block; font-size:.75rem; font-weight:600;
  padding:4px 12px; border-radius:20px; color:#fff; margin-bottom:12px;
}
.article-header h1 {
  font-size:1.65rem; line-height:1.5; margin-bottom:12px; color:var(--c-primary);
}
.article-meta {
  display:flex; flex-wrap:wrap; gap:12px; font-size:.8rem; color:var(--c-text-light);
}

/* ---- TOC ---- */
.toc-widget {
  background:var(--c-card); border-radius:var(--radius-sm);
  padding:20px; box-shadow:var(--shadow); margin-bottom:24px;
  position:sticky; top:calc(var(--header-h) + 16px);
}
.toc-widget h3 { font-size:.9rem; margin-bottom:12px; color:var(--c-primary); }
.toc-widget ul { list-style:none; }
.toc-widget ul ul { padding-left:16px; }
.toc-widget li { margin-bottom:6px; }
.toc-widget a { font-size:.82rem; color:var(--c-text-light); line-height:1.5; }
.toc-widget a:hover { color:var(--c-primary-light); }

/* ---- ARTICLE BODY ---- */
.article-body {
  font-size:.95rem; line-height:1.9; color:#334155;
}
.article-body h1 { display:none; }
.article-body h2 {
  font-size:1.35rem; font-weight:700; margin:40px 0 16px;
  padding-bottom:8px; border-bottom:3px solid var(--c-accent);
  color:var(--c-primary);
}
.article-body h3 {
  font-size:1.1rem; font-weight:700; margin:28px 0 12px;
  color:var(--c-primary);
}
.article-body h4 { font-size:1rem; font-weight:700; margin:20px 0 8px; }
.article-body p { margin-bottom:16px; }
.article-body ul, .article-body ol { margin:12px 0 16px 24px; }
.article-body ul { list-style:disc; }
.article-body ol { list-style:decimal; }
.article-body li { margin-bottom:6px; }
.article-body strong { font-weight:700; }
.article-body a { color:var(--c-primary-light); text-decoration:underline; }
.article-body a:hover { color:var(--c-accent); }
.article-body table {
  width:100%; border-collapse:collapse; margin:16px 0;
  font-size:.9rem;
}
.article-body th, .article-body td {
  border:1px solid var(--c-border); padding:10px 14px; text-align:left;
}
.article-body th { background:#f1f5f9; font-weight:600; }
.article-body blockquote {
  border-left:4px solid var(--c-accent); background:#f0f9ff;
  padding:16px 20px; margin:16px 0; border-radius:0 var(--radius-sm) var(--radius-sm) 0;
  font-size:.9rem; color:#475569;
}
.article-body hr {
  border:none; border-top:2px solid var(--c-border); margin:32px 0;
}
.article-body .headerlink { display:none; }

/* ---- RELATED ---- */
.related-section {
  margin-top:48px; padding-top:32px; border-top:2px solid var(--c-border);
}
.related-section h2 { font-size:1.2rem; margin-bottom:20px; color:var(--c-primary); }
.related-list {
  display:grid; grid-template-columns:1fr; gap:12px;
}
.related-item {
  background:var(--c-card); border-radius:var(--radius-sm); padding:16px;
  box-shadow:0 1px 4px rgba(0,0,0,.06); transition: transform .15s;
  border-left:3px solid var(--c-accent);
}
.related-item:hover { transform:translateX(4px); }
.related-item a { color:var(--c-text); font-size:.9rem; line-height:1.5; }
.related-item a:hover { color:var(--c-primary-light); }
.related-item .related-kw { font-size:.75rem; color:var(--c-text-light); margin-top:4px; }

/* ---- CATEGORY PAGE ---- */
.category-hero {
  background:linear-gradient(135deg, var(--c-primary) 0%, #0284c7 100%);
  color:#fff; padding:40px 20px; text-align:center;
}
.category-hero h1 { font-size:1.6rem; margin-bottom:8px; }
.category-hero p { opacity:.85; }

/* ---- SITEMAP LINK ---- */
.sitemap-section {
  background:var(--c-card); border-radius:var(--radius);
  padding:32px; box-shadow:var(--shadow); margin-top:32px;
}
.sitemap-section h2 { font-size:1.2rem; margin-bottom:16px; color:var(--c-primary); }
.sitemap-section ul { list-style:none; }
.sitemap-section li { margin-bottom:6px; }
.sitemap-section a { font-size:.9rem; }

/* ---- FOOTER ---- */
.site-footer {
  background:var(--c-primary); color:rgba(255,255,255,.85);
  margin-top:60px;
}
.footer-inner {
  max-width:var(--max-w); margin:0 auto; padding:40px 20px;
  display:grid; grid-template-columns:2fr 1fr 1fr; gap:32px;
}
.footer-logo {
  display:flex; align-items:center; gap:8px;
  color:#fff; font-size:1.1rem; font-weight:700; margin-bottom:8px;
}
.footer-desc { font-size:.85rem; opacity:.8; line-height:1.6; }
.footer-col h3 { font-size:.9rem; margin-bottom:12px; color:#fff; }
.footer-col ul { list-style:none; }
.footer-col li { margin-bottom:6px; }
.footer-col a { color:rgba(255,255,255,.75); font-size:.85rem; }
.footer-col a:hover { color:#fff; }
.footer-bottom {
  text-align:center; padding:20px; border-top:1px solid rgba(255,255,255,.15);
  font-size:.8rem; opacity:.7;
}

@media (max-width:768px) {
  .hero h1 { font-size:1.4rem; }
  .hero .hero-sub { font-size:.9rem; }
  .article-layout { grid-template-columns:1fr; }
  .toc-widget { position:static; }
  .article-grid { grid-template-columns:1fr; }
  .cat-grid { grid-template-columns:1fr 1fr; }
  .footer-inner { grid-template-columns:1fr; }
  .footer-col { margin-bottom:20px; }
  .article-header h1 { font-size:1.3rem; }
  .article-body h2 { font-size:1.15rem; }
  .related-list { grid-template-columns:1fr; }
}
@media (max-width:480px) {
  .cat-grid { grid-template-columns:1fr; }
}