:root {
  --accent1: #ffffff; /* 白 */
  --accent2: #d1d5db; /* 薄いグレー */
  --blue-accent: #2d6cdf; /* 差し色の青 */
}

/* ---------- Base ---------- */
.about .section-title {
  font-size: clamp(1.25rem, 1.1rem + 1vw, 1.6rem);
  margin: 0 0 .75rem;
  position: relative;
}
.about .section-title::after {
  content:"";
  display:block;
  width:64px; height:3px;
  background: linear-gradient(90deg,var(--accent2), var(--blue-accent));
  margin:.4rem 0 0;
  border-radius:2px;
}
.about .muted { color: #6b7280; }

/* ---------- HERO ---------- */
.hero {
  position: relative;
  border-radius: 20px;
  overflow: hidden;
  padding: clamp(28px, 6vw, 72px);
  margin: 24px 0 32px;
  color: #1f2937;
  background: #f9fafb;
}
.hero-bg {
  position:absolute; inset:0;
  background:
    radial-gradient(1200px 600px at 80% -10%, rgba(45,108,223,.08), transparent 60%),
    radial-gradient(700px 400px at -5% 100%, rgba(0,0,0,.06), transparent 60%);
  filter: blur(8px);
}
.hero-inner { position:relative; z-index:1; }

.hero-title {
  font-size: clamp(1.6rem, 1.2rem + 2.2vw, 2.6rem);
  line-height: 1.15;
  margin: 0 0 .6rem;
  color: #111827;
}
.hero-title span {
  color: var(--blue-accent); /* 強調したい部分をspanで囲む */
}

.hero-lead {
  font-size: clamp(1rem, .9rem + .6vw, 1.25rem);
  color: #374151;
  opacity:.9;
}

.hero-pills {
  display:flex; flex-wrap:wrap; gap:.5rem; margin-top: .9rem;
}
.pill {
  display:inline-block; padding:.45rem .7rem;
  border-radius: 999px;
  background: #ffffff;
  color:#1f2937;
  border: 1px solid var(--accent2);
  font-size: .85rem; letter-spacing:.02em;
  transition: all .2s ease;
}
.pill:hover {
  background: var(--blue-accent);
  color: #ffffff;
  border-color: var(--blue-accent);
}

/* ---------- Grid Cards (3 cols responsive) ---------- */
.grid3 {
  display:grid; gap:16px;
  grid-template-columns: repeat(3, minmax(0,1fr));
  margin: 12px 0 28px;
}
@media (max-width: 1024px){ .grid3{ grid-template-columns: repeat(2, minmax(0,1fr)); } }
@media (max-width: 680px){ .grid3{ grid-template-columns: 1fr; } }

.card {
  background: #fff;
  border-radius: 16px;
  padding: 18px 18px;
  box-shadow: 0 6px 24px rgba(0,0,0,.06), 0 2px 8px rgba(0,0,0,.05);
  border:1px solid rgba(0,0,0,.06);
}

/* ---------- Lists ---------- */
.icon-list { padding-left: 0; list-style: none; display:grid; gap:.5rem; }
.icon-list li {
  position:relative; padding-left: 1.6rem;
}
.icon-list li::before {
  content:""; position:absolute; left:0; top:.45rem;
  width:10px; height:10px; border-radius:2px;
  background: linear-gradient(135deg,var(--blue-accent), var(--accent2));
  box-shadow: 0 0 0 3px rgba(209,213,219,.25);
}

.stat-list { padding:0; list-style:none; display:grid; gap:.55rem; }
.stat-label { color:#6b7280; margin-right:.5rem; }
.stat-value { font-weight:700; }

/* ---------- Chips for themes ---------- */
.chip-grid { display:grid; gap:.6rem; grid-template-columns: repeat(2,minmax(0,1fr)); padding-left:0; list-style:none; }
@media (max-width: 720px){ .chip-grid{ grid-template-columns: 1fr; } }
.chip-grid li {
  background:#f3f4f6;
  border:1px solid #c7d2fe; /* 薄青 */
  border-radius: 12px;
  padding:.7rem .9rem;
  color: #1f2937;
}

/* ---------- Timeline ---------- */
.timeline { position:relative; margin: 16px 0 24px; }
.timeline::before {
  content:""; position:absolute; left:11px; top:0; bottom:0; width:2px; background:#e5e7eb;
}
.tl-item { display:flex; gap:14px; position:relative; }
.tl-item + .tl-item { margin-top: 10px; }
.dot {
  width:14px; height:14px; border-radius:50%;
  background: var(--blue-accent);
  margin-top:.25rem;
  box-shadow: 0 0 0 4px #ffffff;
}
.tl-body h3 { margin:.05rem 0 .15rem; font-size:1rem; color:#111827; }
.tl-body p { margin:0; color:#374151; }

/* ---------- Fade-in（observer用） ---------- */
.fade-in { opacity:0; transform: translateY(8px); transition: .5s ease; }
.fade-in.visible { opacity:1; transform: none; }

/* ---------- Dark mode ---------- */
@media (prefers-color-scheme: dark){
  .hero { background:#111827; color:#f9fafb; }
  .hero-bg { filter: blur(10px); opacity:.8; }
  .hero-title { color:#f9fafb; }
  .hero-lead { color:#d1d5db; }
  .pill { background:#1f2937; color:#f9fafb; border:1px solid #4b5563; }
  .pill:hover { background: var(--blue-accent); border-color: var(--blue-accent); }
  .card { background:#1f2937; border-color: rgba(255,255,255,.06); box-shadow: 0 6px 24px rgba(0,0,0,.35), 0 2px 8px rgba(0,0,0,.25); }
  .chip-grid li { background:#111827; border-color: #374151; color:#f9fafb; }
  .stat-label { color:#9ca3af; } .stat-value { color:#f9fafb; }
  .icon-list li::before { box-shadow: 0 0 0 3px rgba(229,231,235,.25); }
  .timeline::before { background:#374151; }
  .dot { background: var(--blue-accent); box-shadow: 0 0 0 4px #111827; }
  .tl-body p { color:#d1d5db; }
}
.badge {
  display: inline-block;
  background: #e7eff5;
  color: #222;
  border-radius: 12px;
  padding: 3px 10px;
  margin-left: 6px;
  font-size: 0.9em;
  font-weight: 500;
  line-height: 1.4;
}

@media (prefers-color-scheme: dark) {
  .badge {
    background: rgba(79, 222, 222, 0.15);
    color: #e0faff;
  }
}