/* ════════════════════════════════════════════════
   Bottleneck Diagnostics. Blog / Insights styles
   Matches the live homepage (index.html) design system.
   ════════════════════════════════════════════════ */

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: 'DM Sans', system-ui, -apple-system, sans-serif;
  color: #1A1A1A;
  background: #ffffff;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

:root {
  --navy:    #1E4CA1;
  --navy-dk: #163880;
  --charcoal: #1A1A1A;
  --stone:   #F2F0EC;
  --stone-dk: rgba(26,26,26,0.14);
  --white:   #FFFFFF;
  --text:    #1A1A1A;
  --text-muted: rgba(26,26,26,0.6);
  --border:  rgba(26,26,26,0.14);
  --max: 760px;
  --max-wide: 1080px;
  --radius: 0;
}

.container { width: 100%; max-width: var(--max-wide); margin: 0 auto; padding: 0 24px; }
.narrow { max-width: var(--max); margin: 0 auto; }

.label {
  display: inline-block;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--navy);
  margin-bottom: 16px;
}

h1, h2, h3 { font-family: 'Newsreader', Georgia, serif; line-height: 1.2; font-weight: 700; color: var(--charcoal); }
h1 { font-size: clamp(32px, 4.5vw, 50px); letter-spacing: -0.02em; }
h2 { font-size: clamp(24px, 3vw, 34px); letter-spacing: -0.02em; }
h3 { font-size: 20px; font-weight: 600; }
.serif { font-family: 'Newsreader', Georgia, serif; }

p { font-size: 17px; line-height: 1.75; color: var(--text-muted); }

/* ── Buttons ── */
.btn {
  display: inline-block;
  padding: 16px 32px;
  border-radius: var(--radius);
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 0.01em;
  cursor: pointer;
  text-decoration: none;
  transition: all 0.2s ease;
  border: none;
}
.btn--primary { background: var(--navy); color: var(--white); }
.btn--primary:hover { background: var(--navy-dk); }
.btn--outline-white {
  background: transparent;
  color: var(--white);
  border: 1.5px solid rgba(255,255,255,0.5);
}
.btn--outline-white:hover { background: rgba(255,255,255,0.08); border-color: rgba(255,255,255,0.85); }
.btn--large { padding: 18px 40px; font-size: 16px; }

/* ── Nav ── */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--white);
  border-bottom: 1px solid var(--border);
}
.nav__inner { display: flex; align-items: center; justify-content: space-between; height: 68px; }
.nav__logo { display: flex; align-items: center; text-decoration: none; }
.nav__logo img { height: 40px; width: auto; display: block; }
.nav__right { display: flex; align-items: center; gap: 24px; }
.nav__link { font-size: 14px; color: var(--text-muted); text-decoration: none; font-weight: 500; transition: color 0.15s; }
.nav__link:hover { color: var(--charcoal); }

/* ── Mobile nav (no JS, native <details>) ── */
.nav__menu { display: none; }
.nav__menu > summary {
  list-style: none;
  display: flex; flex-direction: column; justify-content: center; align-items: center;
  gap: 4px; width: 40px; height: 40px;
  background: var(--white); border: 1px solid var(--border); border-radius: 0;
  cursor: pointer;
}
.nav__menu > summary::-webkit-details-marker { display: none; }
.nav__menu > summary span { display: block; width: 18px; height: 2px; background: #1A1A1A; }
.nav__menu-panel {
  position: absolute; top: 68px; left: 0; right: 0;
  background: var(--white);
  border-top: 1px solid var(--border); border-bottom: 1px solid var(--border);
}
.nav__menu-panel a {
  display: block; padding: 16px 24px;
  font-size: 15px; font-weight: 500; color: var(--charcoal); text-decoration: none;
  border-top: 1px solid var(--border);
}
.nav__menu-panel a:first-child { border-top: none; }
.nav__menu-panel a:hover { background: var(--stone); color: #1A1A1A; }

/* ── Article header ── */
.article-head { padding: 64px 0 40px; border-bottom: 1px solid var(--border); }
.breadcrumb { font-size: 13px; color: var(--text-muted); margin-bottom: 24px; }
.breadcrumb a { color: var(--text-muted); text-decoration: none; }
.breadcrumb a:hover { color: var(--navy); }
.breadcrumb span { margin: 0 8px; opacity: 0.5; }
.article-head h1 { margin-bottom: 20px; }
.article-lead { font-size: 20px; color: var(--charcoal); line-height: 1.6; font-weight: 400; }
.article-meta {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-top: 28px;
  font-size: 13px;
  color: var(--text-muted);
}
.article-meta .dot { width: 3px; height: 3px; border-radius: 0; background: var(--border); }

/* ── Article body / prose ── */
.prose { padding: 48px 0 8px; }
.prose h2 { margin: 48px 0 16px; }
.prose h3 { margin: 32px 0 12px; font-size: 19px; }
.prose p { margin-bottom: 20px; }
.prose p:first-child { margin-top: 0; }
.prose strong { color: var(--charcoal); font-weight: 600; }
.prose ul, .prose ol { margin: 0 0 24px 0; padding-left: 0; list-style: none; }
.prose ul li, .prose ol li {
  font-size: 17px;
  color: var(--text-muted);
  line-height: 1.7;
  padding: 6px 0 6px 26px;
  position: relative;
}
.prose ul li::before {
  content: '';
  position: absolute;
  left: 2px;
  top: 16px;
  width: 7px;
  height: 7px;
  border-radius: 0;
  background: var(--navy);
}
.prose ol { counter-reset: item; }
.prose ol li { counter-increment: item; }
.prose ol li::before {
  content: counter(item);
  position: absolute;
  left: 0;
  top: 6px;
  font-size: 12px;
  font-weight: 700;
  color: var(--navy);
}
.prose a { color: var(--navy); text-decoration: underline; text-underline-offset: 2px; }

/* ── Key sentence highlight (from homepage) ── */
.key-sentence {
  display: block;
  background: var(--stone);
  border-left: 2px solid var(--navy);
  padding: 18px 22px;
  margin: 8px 0 28px;
  font-weight: 600;
  font-size: 18px;
  color: var(--charcoal);
  line-height: 1.55;
}

/* ── Comparison table ── */
.data-table { width: 100%; border-collapse: collapse; margin: 8px 0 28px; font-size: 15px; }
.data-table th, .data-table td { text-align: left; padding: 12px 14px; border-bottom: 1px solid var(--border); }
.data-table th { font-size: 12px; letter-spacing: 0.04em; text-transform: uppercase; color: var(--text-muted); font-weight: 600; }
.data-table td { color: var(--charcoal); }
.data-table tr td:first-child { color: var(--text-muted); }

/* ── FAQ ── */
.faq { margin: 16px 0 8px; }
.faq-item { border-bottom: 1px solid var(--border); }
.faq-item:first-child { border-top: 1px solid var(--border); }
.faq-q {
  display: flex; justify-content: space-between; align-items: center;
  padding: 22px 0; cursor: pointer; font-size: 16px; font-weight: 600;
  color: var(--charcoal); gap: 16px; user-select: none; list-style: none;
}
.faq-q::-webkit-details-marker { display: none; }
.faq-icon {
  flex-shrink: 0; width: 24px; height: 24px; border-radius: 0;
  background: var(--white); border: 1.5px solid var(--border);
  display: flex; align-items: center; justify-content: center;
  font-size: 16px; line-height: 1; color: var(--navy); font-weight: 400; transition: transform 0.2s;
}
details[open] .faq-icon { transform: rotate(45deg); }
.faq-a { padding: 0 0 24px; font-size: 16px; line-height: 1.75; color: var(--text-muted); max-width: 640px; }

/* ── CTA block ── */
.cta-block { background: var(--navy); color: var(--white); margin: 56px 0 0; padding: 56px 0; }
.cta-block .container { max-width: var(--max); text-align: center; }
.cta-block h2 { color: var(--white); margin-bottom: 16px; }
.cta-block p { color: rgba(255,255,255,0.72); margin-bottom: 32px; font-size: 17px; }
.cta-note { margin-top: 16px; font-size: 13px; color: rgba(255,255,255,0.5); }

/* ── Related / next reads ── */
.related { padding: 56px 0; background: var(--stone); }
.related h2 { font-size: 22px; margin-bottom: 28px; }
.related-grid { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 20px; }
.related-card {
  background: var(--white); border: 1px solid var(--border); border-radius: 0;
  padding: 24px; text-decoration: none; display: block; transition: all 0.2s;
}
.related-card:hover { border-color: var(--navy); }
.related-card__cat { font-size: 11px; font-weight: 700; letter-spacing: 0.1em; text-transform: uppercase; color: var(--navy); display: block; margin-bottom: 10px; }
.related-card__title { font-size: 16px; font-weight: 600; color: var(--charcoal); line-height: 1.4; }
@media (max-width: 720px) { .related-grid { grid-template-columns: 1fr; } }

/* ── Blog hub ── */
.hub-head { padding: 72px 0 16px; }
.hub-head .label { display: block; }
.hub-head p { font-size: 19px; color: var(--charcoal); max-width: 620px; }
.hub-list { padding: 32px 0 80px; }
.hub-item {
  display: block; text-decoration: none; padding: 32px 0; border-bottom: 1px solid var(--border);
  transition: padding-left 0.2s;
}
.hub-item:first-child { border-top: 1px solid var(--border); }
.hub-item:hover { padding-left: 8px; }
.hub-item__cat { display: block; font-size: 11px; font-weight: 700; letter-spacing: 0.1em; text-transform: uppercase; color: var(--navy); }
.hub-item__title { display: block; font-size: 24px; font-weight: 700; color: var(--charcoal); margin: 10px 0 8px; line-height: 1.25; letter-spacing: -0.01em; }
.hub-item__sub { display: block; font-size: 16px; color: var(--text-muted); line-height: 1.6; max-width: 680px; }
.hub-item--pillar .hub-item__title { font-size: 30px; }

/* ── Footer ── */
.footer { background: #1A1A1A; padding: 48px 0; margin-top: 0; }
.footer__inner { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 24px; }
.footer__brand { display: inline-flex; align-items: center; text-decoration: none; }
.footer__brand img { height: 30px; width: auto; display: block; opacity: 0.9; }
.footer__copy { font-size: 13px; color: rgba(255,255,255,0.35); }
.footer__links { display: flex; gap: 24px; }
.footer__links a { font-size: 13px; color: rgba(255,255,255,0.4); text-decoration: none; transition: color 0.15s; }
.footer__links a:hover { color: rgba(255,255,255,0.8); }

@media (max-width: 600px) {
  .nav__link { display: none; }
  .nav__menu { display: block; }
  .article-head { padding: 40px 0 32px; }
  .footer__inner { flex-direction: column; align-items: flex-start; }
}