:root {
  --color-navy: #17243a;
  --color-navy-light: #223452;
  --color-gold: #b6975b;
  --color-bg: #f7f8fa;
  --color-text: #1f2933;
  --color-muted: #657080;
  --color-white: #ffffff;
  --color-border: #d9dee7;
  --max-width: 1120px;
  --radius: 18px;
  --shadow: 0 18px 45px rgba(23, 36, 58, 0.08);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: "Noto Sans JP","Hiragino Kaku Gothic ProN","Yu Gothic",Meiryo,sans-serif;
  color: var(--color-text);
  background: var(--color-white);
  line-height: 1.85;
}

a { color: inherit; text-decoration: none; }

/* ─── Header ─── */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(255,255,255,.94);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
}
.header-inner {
  max-width: var(--max-width); margin: 0 auto;
  padding: 16px 24px;
  display: flex; justify-content: space-between; align-items: center; gap: 24px;
}
.logo {
  display: flex; flex-direction: column; line-height: 1.2;
  font-weight: 700; color: var(--color-navy); letter-spacing: .04em;
}
.logo span { font-size: 12px; color: var(--color-muted); font-weight: 500; letter-spacing: .08em; margin-top: 4px; }
.nav { display: flex; gap: 18px; align-items: center; font-size: 14px; color: var(--color-navy); }
.nav a { padding: 8px 0; border-bottom: 2px solid transparent; }
.nav a:hover, .nav a[aria-current="page"] { color: var(--color-gold); border-bottom-color: var(--color-gold); }
.nav-contact {
  padding: 9px 16px !important;
  background: var(--color-navy); color: var(--color-white) !important;
  border-radius: 999px; border-bottom: none !important;
}

/* ─── Hero ─── */
.page-hero {
  background:
    radial-gradient(circle at top right, rgba(182,151,91,.16), transparent 34%),
    linear-gradient(135deg, #ffffff 0%, #f4f6f9 60%, #eef1f5 100%);
  padding: 88px 24px 72px;
}
.hero-inner, .section-inner { max-width: var(--max-width); margin: 0 auto; }
.breadcrumb { font-size: 13px; color: var(--color-muted); margin-bottom: 24px; }
.breadcrumb a { color: var(--color-navy); }
.eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  color: var(--color-gold); font-size: 14px; font-weight: 700;
  letter-spacing: .12em; text-transform: uppercase; margin-bottom: 18px;
}
.eyebrow::before { content: ""; width: 34px; height: 1px; background: var(--color-gold); }
.page-hero h1 {
  margin: 0 0 24px; color: var(--color-navy);
  font-size: clamp(36px, 5vw, 58px); line-height: 1.25; letter-spacing: .02em;
}
.hero-lead { max-width: 800px; font-size: 17px; color: #334155; margin: 0; line-height: 1.9; }

/* ─── Sections ─── */
.section { padding: 80px 24px; }
.section-soft { background: var(--color-bg); }

.section-title { max-width: 860px; margin-bottom: 48px; }
.section-title h2 { margin: 0 0 16px; color: var(--color-navy); font-size: clamp(24px, 3.5vw, 36px); line-height: 1.35; }
.section-title p { margin: 0; color: var(--color-muted); font-size: 16px; }

/* ─── Filter ─── */
.filter-row { display: flex; flex-wrap: wrap; gap: 10px; margin-bottom: 40px; }
.filter-tag {
  padding: 7px 18px; border-radius: 999px; border: 1.5px solid var(--color-border);
  background: var(--color-white); color: var(--color-muted);
  font-size: 13px; font-weight: 700; cursor: pointer;
  font-family: inherit;
  transition: all .2s ease;
}
.filter-tag:hover { border-color: var(--color-gold); color: var(--color-gold); }
.filter-tag.active { background: var(--color-navy); border-color: var(--color-navy); color: var(--color-white); }

/* ─── Article grid ─── */
.article-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 24px; }

.article-card {
  background: var(--color-white); border: 1px solid var(--color-border);
  border-radius: var(--radius); padding: 28px 30px;
  box-shadow: 0 6px 24px rgba(23,36,58,.05);
  display: flex; flex-direction: column; gap: 14px;
  transition: box-shadow .2s ease, transform .2s ease;
}
.article-card:hover { box-shadow: var(--shadow); transform: translateY(-2px); }

.card-meta { display: flex; align-items: center; gap: 12px; }
.cat-badge {
  display: inline-block; padding: 3px 12px; border-radius: 999px;
  font-size: 11px; font-weight: 700; letter-spacing: .06em;
}
.cat-ai-governance { background: #e8edf8; color: #2f5088; }
.cat-ai-management { background: #e8f4ef; color: #2f6f5e; }
.cat-security { background: #fce8e8; color: #a03030; }
.cat-insourcing { background: #f7f0e3; color: #8c6a22; }

time { font-size: 12px; color: var(--color-muted); }

.article-card h2 { margin: 0; font-size: 18px; line-height: 1.45; }
.article-card h2 a { color: var(--color-navy); }
.article-card h2 a:hover { color: var(--color-gold); }

.article-lead { margin: 0; font-size: 14px; color: var(--color-muted); line-height: 1.85; flex: 1; }

.tag-row { display: flex; flex-wrap: wrap; gap: 6px; }
.tag {
  display: inline-block; padding: 3px 10px; border-radius: 999px;
  background: rgba(182,151,91,.12); color: var(--color-gold); font-size: 11px; font-weight: 700;
}

.read-more {
  display: inline-flex; align-items: center; gap: 4px;
  color: var(--color-gold); font-size: 13px; font-weight: 700;
  margin-top: 4px;
  transition: gap .2s ease;
}
.read-more:hover { gap: 8px; }

/* ─── Tools ─── */
.tool-grid { display: grid; grid-template-columns: repeat(3, minmax(0,1fr)); gap: 20px; }
.tool-card {
  background: var(--color-white); border: 1px solid var(--color-border);
  border-radius: var(--radius); padding: 28px 24px;
  box-shadow: 0 4px 16px rgba(23,36,58,.04);
  display: flex; flex-direction: column; gap: 12px;
}
.tool-icon { font-size: 28px; line-height: 1; }
.tool-card h3 { margin: 0; font-size: 17px; color: var(--color-navy); }
.tool-card p { margin: 0; font-size: 13px; color: var(--color-muted); line-height: 1.8; flex: 1; }
.tool-link {
  display: inline-flex; align-items: center;
  color: var(--color-gold); font-size: 13px; font-weight: 700;
  margin-top: auto;
}
.tool-link:hover { text-decoration: underline; }

/* ─── CTA ─── */
.cta-section { text-align: center; padding: 88px 24px; background: var(--color-bg); }
.cta-section .eyebrow { display: inline-flex; }
.cta-section h2 { margin: 18px 0 18px; color: var(--color-navy); font-size: clamp(26px,4vw,40px); line-height: 1.35; }
.cta-section p { margin: 0 auto 34px; max-width: 680px; color: var(--color-muted); font-size: 16px; }
.btn-primary {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 18px 40px; background: var(--color-navy); color: var(--color-white);
  border-radius: 999px; font-weight: 700; font-size: 16px;
  box-shadow: 0 12px 28px rgba(23,36,58,.2);
  transition: transform .2s ease, box-shadow .2s ease;
}
.btn-primary:hover { transform: translateY(-3px); box-shadow: 0 20px 40px rgba(23,36,58,.28); }

/* ─── Footer ─── */
.site-footer { background: #101927; color: var(--color-white); padding: 38px 24px; }
.footer-inner {
  max-width: var(--max-width); margin: 0 auto;
  display: flex; justify-content: space-between; gap: 24px; align-items: center; flex-wrap: wrap;
}
.footer-links { display: flex; gap: 18px; font-size: 14px; color: rgba(255,255,255,.72); }
.copyright { color: rgba(255,255,255,.58); font-size: 13px; }
.footer-disclaimer {
  max-width: var(--max-width); margin: 18px auto 0;
  padding-top: 16px; border-top: 1px solid rgba(255,255,255,.1);
  font-size: 11px; color: rgba(255,255,255,.42); line-height: 1.7;
}

/* ─── Responsive ─── */
@media (max-width: 960px) {
  .nav { display: none; }
  .article-grid { grid-template-columns: 1fr; }
  .tool-grid { grid-template-columns: 1fr; }
}
@media (max-width: 640px) {
  .page-hero { padding: 64px 20px 52px; }
  .section { padding: 60px 20px; }
}