@import url('https://fonts.googleapis.com/css2?family=DM+Sans:ital,opsz,wght@0,9..40,300;0,9..40,400;0,9..40,500;0,9..40,700;0,9..40,800;0,9..40,900&family=Noto+Sans+JP:wght@400;500;700;900&display=swap');

:root {
  --bg: #080a12;
  --bg-card: #0f1220;
  --bg-section: #0b0d17;
  --primary: #3b82f6;
  --secondary: #818cf8;
  --accent: #06b6d4;
  --gradient: linear-gradient(135deg, #3b82f6 0%, #818cf8 100%);
  --text: #f1f5ff;
  --muted: #8896b3;
  --border: rgba(255,255,255,0.06);
  --border-hover: rgba(59,130,246,0.5);
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scrollbar-gutter: stable; }
body {
  font-family: 'DM Sans', 'Noto Sans JP', sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}
a { color: inherit; text-decoration: none; }
.container { max-width: 1160px; margin: 0 auto; padding: 0 28px; }
.container-wide { max-width: 1547px; margin: 0 auto; padding: 0 28px; }

/* Header */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(10,14,26,.88);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border-bottom: 1px solid var(--border);
}
.site-header .container,
.site-header .container-wide {
  display: flex; align-items: center;
  justify-content: space-between; height: 68px;
}
.logo { display: flex; align-items: center; gap: 12px; font-weight: 800; font-size: 1.05rem; letter-spacing: -0.02em; }
.logo-icon { flex-shrink: 0; }
.logo-dot {
  background: var(--gradient);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
}
.site-nav { display: flex; align-items: center; gap: 4px; }
.site-nav a {
  color: var(--muted); font-size: 0.875rem; font-weight: 500;
  padding: 7px 14px; border-radius: 8px;
  transition: color .2s, background .2s; letter-spacing: -0.01em;
}
.site-nav a:hover { color: var(--text); background: rgba(255,255,255,.05); }

/* Hero */
.hero {
  padding: 100px 0 88px;
  text-align: center;
  position: relative; overflow: hidden;
  background: var(--bg);
}
.hero::before {
  content: '';
  position: absolute; inset: 0;
  background:
    radial-gradient(ellipse 65% 55% at 50% 0%, rgba(59,130,246,.22) 0%, transparent 70%),
    radial-gradient(ellipse 40% 30% at 80% 40%, rgba(129,140,248,.10) 0%, transparent 60%);
  pointer-events: none;
}
.hero::after {
  content: '';
  position: absolute; inset: 0;
  background-image:
    linear-gradient(rgba(59,130,246,.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(59,130,246,.04) 1px, transparent 1px);
  background-size: 56px 56px;
  pointer-events: none;
}
.hero .container { position: relative; z-index: 1; }
.hero-eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  background: rgba(59,130,246,.1);
  border: 1px solid rgba(59,130,246,.25);
  color: #93c5fd;
  padding: 6px 18px; border-radius: 9999px;
  font-size: .72rem; font-weight: 700; letter-spacing: .1em;
  text-transform: uppercase; margin-bottom: 28px;
}
.hero h1 {
  font-size: clamp(2.4rem, 6vw, 4rem);
  font-weight: 800; line-height: 1.1; letter-spacing: -0.04em;
  margin-bottom: 24px;
}
.hero h1 .gradient-text {
  background: var(--gradient);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
}
.hero-desc { color: var(--muted); font-size: 1rem; max-width: 480px; margin: 0 auto; line-height: 1.85; }

/* Section */
.section { padding: 80px 0; }
.section-header { display: flex; align-items: center; gap: 20px; margin-bottom: 40px; }
.section-title { font-size: 1rem; font-weight: 700; letter-spacing: .06em; text-transform: uppercase; color: var(--muted); white-space: nowrap; }
.section-line { flex: 1; height: 1px; background: var(--border); }

/* Cards */
.article-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(310px, 1fr)); gap: 20px; }
.article-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 18px; padding: 28px;
  display: block; position: relative; overflow: hidden;
  transition: border-color .25s, transform .25s;
}
.article-card::before {
  content: '';
  position: absolute; inset: 0;
  background: radial-gradient(ellipse 80% 60% at 50% -20%, rgba(59,130,246,.07) 0%, transparent 70%);
  opacity: 0; transition: opacity .3s;
}
.article-card:hover { border-color: var(--border-hover); transform: translateY(-4px); }
.article-card:hover::before { opacity: 1; }
.card-meta { display: flex; align-items: center; gap: 10px; margin-bottom: 16px; }
.card-tag {
  background: rgba(59,130,246,.1); color: #93c5fd;
  border: 1px solid rgba(59,130,246,.2);
  padding: 3px 10px; border-radius: 9999px;
  font-size: .68rem; font-weight: 700; letter-spacing: .06em; text-transform: uppercase;
}
.card-date { color: var(--muted); font-size: .78rem; }
.card-title { font-size: .975rem; font-weight: 700; line-height: 1.5; letter-spacing: -0.01em; margin-bottom: 10px; }
.card-excerpt { font-size: .87rem; color: var(--muted); line-height: 1.75; display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden; }
.card-arrow { margin-top: 20px; color: var(--accent); font-size: .82rem; font-weight: 600; }

/* Post */
.post-header {
  padding: 80px 0 56px;
  position: relative; overflow: hidden;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  margin-bottom: 56px;
}
.post-header::before {
  content: '';
  position: absolute; inset: 0;
  background: radial-gradient(ellipse 70% 80% at 50% 0%, rgba(59,130,246,.16) 0%, transparent 70%);
  pointer-events: none;
}
.post-header .container { position: relative; z-index: 1; }
.back-link {
  display: inline-flex; align-items: center; gap: 6px;
  color: var(--muted); font-size: .85rem; font-weight: 500;
  margin-bottom: 32px; transition: color .2s;
}
.back-link:hover { color: var(--text); }
.post-meta { display: flex; gap: 10px; align-items: center; margin-bottom: 20px; }
.post-tag {
  background: rgba(59,130,246,.1); color: #93c5fd;
  border: 1px solid rgba(59,130,246,.2);
  padding: 4px 12px; border-radius: 9999px;
  font-size: .68rem; font-weight: 700; letter-spacing: .08em; text-transform: uppercase;
}
.post-date { color: var(--muted); font-size: .82rem; }
.post-title { font-size: clamp(1.6rem, 3.5vw, 2.5rem); font-weight: 800; line-height: 1.25; letter-spacing: -0.03em; }
.post-content { max-width: 740px; margin: 0 auto 80px; font-size: 1rem; line-height: 1.9; }
.post-content h2 { font-size: 1.35rem; font-weight: 800; letter-spacing: -0.02em; margin: 56px 0 16px; padding-left: 16px; border-left: 3px solid var(--primary); }
.post-content h3 { font-size: 1.05rem; font-weight: 700; letter-spacing: -0.01em; margin: 36px 0 12px; color: #93c5fd; }
.post-content p { margin-bottom: 20px; }
.post-content a { color: var(--accent); border-bottom: 1px solid rgba(6,182,212,.3); transition: border-color .2s; }
.post-content a:hover { border-color: var(--accent); }
.post-content ul, .post-content ol { margin: 16px 0 24px 28px; }
.post-content li { margin-bottom: 8px; }
.post-content strong { color: var(--text); font-weight: 700; }
.post-content blockquote { border-left: 3px solid var(--primary); background: rgba(59,130,246,.06); padding: 18px 22px; border-radius: 0 10px 10px 0; margin: 28px 0; color: var(--muted); font-style: italic; }
.post-content table { width: 100%; border-collapse: collapse; margin: 28px 0; font-size: .875rem; }
.post-content th { background: rgba(59,130,246,.1); padding: 12px 16px; border: 1px solid var(--border); font-weight: 700; text-align: left; }
.post-content td { padding: 12px 16px; border: 1px solid var(--border); color: var(--muted); }
.post-content tr:nth-child(even) td { background: rgba(255,255,255,.02); }
.post-content figure { margin: 32px 0; }
.post-content figure img { max-width: 100%; border-radius: 12px; border: 1px solid var(--border); display: block; }
.post-content figcaption { font-size: .75rem; color: var(--muted); margin-top: 8px; text-align: center; line-height: 1.5; }

/* CTA */
.cta-banner {
  background: linear-gradient(135deg, rgba(59,130,246,.09), rgba(129,140,248,.07));
  border: 1px solid rgba(59,130,246,.18);
  border-radius: 20px; padding: 44px; text-align: center; margin: 64px 0;
  position: relative; overflow: hidden;
}
.cta-banner::before {
  content: '';
  position: absolute; top: 0; left: 50%; transform: translateX(-50%);
  width: 70%; height: 1px;
  background: linear-gradient(90deg, transparent, rgba(59,130,246,.6), transparent);
}
.cta-banner h3 { font-size: 1.2rem; font-weight: 800; letter-spacing: -0.02em; margin-bottom: 10px; }
.cta-banner p { color: var(--muted); font-size: .9rem; margin-bottom: 24px; }
.btn {
  display: inline-flex; align-items: center; gap: 6px;
  background: var(--gradient); color: #fff; font-weight: 700;
  padding: 13px 30px; border-radius: 9999px;
  font-size: .9rem; letter-spacing: -0.01em;
  transition: opacity .2s, transform .2s;
}
.btn:hover { opacity: .88; transform: translateY(-2px); }

/* Footer */
.site-footer {
  margin-top: auto;
  background: #05060a;
  border-top: 1px solid var(--border);
  padding: 40px 0;
  color: var(--muted);
}
.footer-inner { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 12px; margin-bottom: 24px; }
.footer-brand { display: flex; align-items: center; gap: 10px; font-weight: 700; color: var(--text); letter-spacing: -0.02em; }
.footer-links a { color: var(--muted); font-size: .82rem; margin-left: 20px; transition: color .2s; }
.footer-links a:hover { color: var(--text); }
.footer-copy { font-size: .72rem; text-align: center; padding-top: 20px; border-top: 1px solid var(--border); line-height: 1.6; }

/* Author */
.post-author {
  display: flex; align-items: flex-start; gap: 16px;
  background: rgba(59,130,246,.05);
  border: 1px solid rgba(59,130,246,.14);
  border-radius: 16px; padding: 22px 26px; margin-bottom: 44px;
}
.author-avatar {
  width: 48px; height: 48px; flex-shrink: 0;
  background: var(--gradient); border-radius: 12px;
  display: flex; align-items: center; justify-content: center;
  font-size: 1.2rem; color: white;
}
.author-name { font-weight: 700; font-size: .95rem; margin-bottom: 4px; letter-spacing: -0.01em; }
.author-bio { font-size: .8rem; color: var(--muted); line-height: 1.6; }

/* ─── HAMBURGER ─── */
.nav-toggle {
  display: none; background: none; border: none; cursor: pointer;
  flex-direction: column; justify-content: center; gap: 5px; padding: 6px;
}
.nav-toggle span {
  display: block; width: 22px; height: 2px;
  background: var(--muted); border-radius: 2px;
  transition: transform .25s, opacity .25s;
}
.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ─── MOBILE (≤ 768px) ─── */
@media (max-width: 768px) {
  .container { padding: 0 16px; }
  .container-wide { padding: 0 16px; }

  .nav-toggle { display: flex; }
  .site-nav {
    display: none; flex-direction: column; gap: 0;
    position: absolute; top: 68px; left: 0; right: 0;
    background: rgba(8,10,18,.97); border-bottom: 1px solid var(--border);
    padding: 8px 0; z-index: 99;
  }
  .site-nav.open { display: flex; }
  .site-nav a { padding: 13px 20px; border-radius: 0; display: block; font-size: .9rem; }

  .hero { padding: 72px 0 60px; }
  .article-grid { grid-template-columns: 1fr; }

  .footer-inner { flex-direction: column; align-items: flex-start; gap: 16px; }
  .footer-links { display: flex; flex-wrap: wrap; gap: 8px; }
  .footer-links a { margin: 0; }

  /* 記事本文テーブルを横スクロール可能に */
  .post-content table { display: block; overflow-x: auto; -webkit-overflow-scrolling: touch; }
}