:root {
  --primary: #1a3a5c;
  --accent: #2e86c1;
  --accent-light: #aed6f1;
  --gold: #d4ac0d;
  --bg: #f4f6f9;
  --card: #ffffff;
  --text: #1c1c1e;
  --muted: #6b7280;
  --border: #dce3ed;
  --radius: 10px;
  --shadow: 0 2px 12px rgba(0,0,0,0.08);
}

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

body {
  font-family: 'Segoe UI', system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
}

/* ── NAV ── */
nav {
  background: var(--primary);
  padding: 0 2rem;
  display: flex;
  align-items: center;
  gap: 0;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 8px rgba(0,0,0,0.25);
}

nav .brand {
  color: var(--gold);
  font-weight: 700;
  font-size: 1rem;
  text-decoration: none;
  padding: 1rem 1.5rem 1rem 0;
  border-right: 1px solid rgba(255,255,255,0.15);
  margin-right: 0.5rem;
  white-space: nowrap;
}

nav a {
  color: rgba(255,255,255,0.8);
  text-decoration: none;
  padding: 1rem 0.9rem;
  font-size: 0.82rem;
  transition: color 0.2s;
  white-space: nowrap;
}

nav a:hover, nav a.active { color: #fff; }
nav a.active { border-bottom: 2px solid var(--gold); }

/* ── HERO ── */
.hero {
  background: linear-gradient(135deg, var(--primary) 0%, #0d2137 100%);
  color: white;
  padding: 4rem 2rem;
  text-align: center;
}

.hero h1 { font-size: 2.4rem; font-weight: 700; margin-bottom: 0.75rem; }
.hero .subtitle { font-size: 1.1rem; opacity: 0.8; max-width: 640px; margin: 0 auto 1.5rem; }
.hero .tag-row { display: flex; gap: 0.5rem; justify-content: center; flex-wrap: wrap; }
.tag {
  background: rgba(255,255,255,0.12);
  border: 1px solid rgba(255,255,255,0.25);
  padding: 0.25rem 0.75rem;
  border-radius: 20px;
  font-size: 0.78rem;
}

/* ── PAGE HERO (inner pages) ── */
.page-hero {
  background: linear-gradient(135deg, var(--primary) 0%, #0d2137 100%);
  color: white;
  padding: 3rem 2rem;
}

.page-hero .breadcrumb {
  font-size: 0.8rem;
  opacity: 0.6;
  margin-bottom: 0.5rem;
}

.page-hero .breadcrumb a { color: var(--accent-light); text-decoration: none; }
.page-hero h1 { font-size: 2rem; font-weight: 700; margin-bottom: 0.5rem; }
.page-hero .lead { opacity: 0.85; max-width: 640px; font-size: 1rem; }

/* ── LAYOUT ── */
.container { max-width: 1100px; margin: 0 auto; padding: 0 1.5rem; }
.content { padding: 3rem 1.5rem; max-width: 1100px; margin: 0 auto; }

/* ── GRID ── */
.grid-3 { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 1.5rem; }
.grid-2 { display: grid; grid-template-columns: repeat(auto-fill, minmax(420px, 1fr)); gap: 1.5rem; }

/* ── CARDS ── */
.card {
  background: var(--card);
  border-radius: var(--radius);
  border: 1px solid var(--border);
  padding: 1.75rem;
  box-shadow: var(--shadow);
}

.card h3 { font-size: 1.05rem; margin-bottom: 0.5rem; color: var(--primary); }
.card p { font-size: 0.9rem; color: var(--muted); }

/* ── SECTION CARDS (W/H/Y/W) ── */
.whyw-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 1.25rem;
  margin: 2rem 0;
}

.whyw-card {
  background: var(--card);
  border-radius: var(--radius);
  border: 1px solid var(--border);
  padding: 1.5rem;
  box-shadow: var(--shadow);
}

.whyw-card .icon {
  font-size: 1.8rem;
  margin-bottom: 0.6rem;
}

.whyw-card h4 {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--accent);
  margin-bottom: 0.4rem;
}

.whyw-card p { font-size: 0.88rem; color: var(--muted); }

/* ── SECTION HEADING ── */
.section-label {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--accent);
  background: var(--accent-light);
  padding: 0.2rem 0.7rem;
  border-radius: 20px;
  margin-bottom: 0.75rem;
}

h2.section-title {
  font-size: 1.55rem;
  color: var(--primary);
  margin-bottom: 0.5rem;
}

.section-desc { color: var(--muted); margin-bottom: 2rem; font-size: 0.95rem; }

/* ── IMPORTANCE BAND ── */
.importance-band {
  background: linear-gradient(135deg, #0d2137 0%, var(--primary) 100%);
  color: white;
  padding: 3rem 2rem;
  margin: 3rem 0;
  border-radius: var(--radius);
}

.importance-band h2 { font-size: 1.4rem; margin-bottom: 1.5rem; }
.importance-band ul { list-style: none; display: grid; grid-template-columns: repeat(auto-fill, minmax(240px,1fr)); gap: 1rem; }
.importance-band li {
  background: rgba(255,255,255,0.08);
  border: 1px solid rgba(255,255,255,0.15);
  border-radius: 8px;
  padding: 1rem 1.25rem;
  font-size: 0.9rem;
}

.importance-band li strong { display: block; color: var(--gold); margin-bottom: 0.25rem; }

/* ── TIMELINE ── */
.timeline { border-left: 3px solid var(--accent-light); padding-left: 1.75rem; margin: 2rem 0; }
.timeline-item { margin-bottom: 1.75rem; position: relative; }
.timeline-item::before {
  content: '';
  position: absolute;
  left: -2.1rem;
  top: 0.4rem;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--accent);
  border: 2px solid white;
  box-shadow: 0 0 0 2px var(--accent);
}
.timeline-item h4 { color: var(--primary); font-size: 1rem; margin-bottom: 0.25rem; }
.timeline-item p { color: var(--muted); font-size: 0.88rem; }

/* ── NAV LINKS ── */
.page-nav {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
}

.page-nav a {
  text-decoration: none;
  color: var(--accent);
  font-size: 0.88rem;
  font-weight: 600;
}

.page-nav a:hover { text-decoration: underline; }

/* ── INDEX TOPIC CARDS ── */
.topic-card {
  background: var(--card);
  border-radius: var(--radius);
  border: 1px solid var(--border);
  padding: 1.75rem;
  box-shadow: var(--shadow);
  text-decoration: none;
  color: inherit;
  display: block;
  transition: transform 0.15s, box-shadow 0.15s;
}

.topic-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 24px rgba(0,0,0,0.12);
}

.topic-card .tc-icon {
  font-size: 2rem;
  margin-bottom: 0.75rem;
}

.topic-card .tc-label {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--accent);
  font-weight: 700;
  margin-bottom: 0.25rem;
}

.topic-card h3 { font-size: 1.1rem; color: var(--primary); margin-bottom: 0.4rem; }
.topic-card p { font-size: 0.85rem; color: var(--muted); }

/* ── IMPLEMENTATION BRIDGE ── */
.impl-bridge {
  background: #fff8e6;
  border: 1px solid #f0d050;
  border-radius: var(--radius);
  padding: 1.5rem 1.75rem;
  margin: 2rem 0;
}

.impl-bridge .ib-label {
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: #a07a00;
  margin-bottom: 0.4rem;
}

.impl-bridge h4 { color: var(--primary); margin-bottom: 0.5rem; }
.impl-bridge p { font-size: 0.88rem; color: var(--muted); }
.impl-bridge code {
  background: rgba(0,0,0,0.06);
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
  font-size: 0.82rem;
  font-family: 'Cascadia Code', 'Consolas', monospace;
}

/* ── FOOTER ── */
footer {
  background: var(--primary);
  color: rgba(255,255,255,0.6);
  text-align: center;
  padding: 2rem;
  font-size: 0.82rem;
  margin-top: 4rem;
}

footer strong { color: var(--gold); }