/* =========================================================
   BestAICertifications.com — Design System
   Lightweight, fast, no framework. Optimized for Core Web Vitals.
   ========================================================= */

:root {
  --bg: #ffffff;
  --bg-alt: #f6f8fc;
  --bg-dark: #0e1726;
  --text: #1a2233;
  --text-soft: #4a5568;
  --muted: #6b7688;
  --border: #e3e8f0;
  --brand: #2563eb;
  --brand-dark: #1d4ed8;
  --brand-soft: #eaf1ff;
  --accent: #0ea5a4;
  --gold: #f59e0b;
  --good: #16a34a;
  --bad: #dc2626;
  --shadow: 0 1px 3px rgba(16,24,40,.06), 0 8px 24px rgba(16,24,40,.06);
  --shadow-lg: 0 12px 40px rgba(16,24,40,.12);
  --radius: 12px;
  --radius-sm: 8px;
  --maxw: 1120px;
  --readw: 760px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  font-family: var(--font);
  color: var(--text);
  background: var(--bg);
  line-height: 1.65;
  font-size: 18px;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; height: auto; display: block; }

a { color: var(--brand); text-decoration: none; }
a:hover { text-decoration: underline; }

.container { max-width: var(--maxw); margin: 0 auto; padding: 0 20px; }

/* ---------- Header / Nav ---------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255,255,255,.92);
  backdrop-filter: saturate(160%) blur(8px);
  border-bottom: 1px solid var(--border);
}
.nav-wrap { display: flex; align-items: center; justify-content: space-between; height: 64px; gap: 16px; }
.logo { font-weight: 800; font-size: 1.2rem; color: var(--text); letter-spacing: -.02em; white-space: nowrap; }
.logo span { color: var(--brand); }
.logo:hover { text-decoration: none; }
.main-nav { display: flex; gap: 4px; align-items: center; overflow-x: auto; }
.main-nav a {
  color: var(--text-soft); font-weight: 600; font-size: .92rem;
  padding: 8px 12px; border-radius: 8px; white-space: nowrap;
}
.main-nav a:hover { background: var(--bg-alt); color: var(--brand); text-decoration: none; }
.nav-cta { background: var(--brand); color: #fff !important; }
.nav-cta:hover { background: var(--brand-dark); color: #fff !important; }

/* ---------- Hero ---------- */
.hero {
  background: linear-gradient(160deg, #0e1726 0%, #15294d 60%, #1d4ed8 130%);
  color: #fff; padding: 72px 0 64px;
}
.hero h1 { font-size: clamp(2rem, 5vw, 3.1rem); line-height: 1.1; margin: 0 0 18px; letter-spacing: -.03em; }
.hero p { font-size: 1.2rem; color: #c7d2e6; max-width: 680px; margin: 0 0 28px; }
.hero .eyebrow { color: #7dd3fc; font-weight: 700; letter-spacing: .08em; text-transform: uppercase; font-size: .8rem; margin-bottom: 14px; }
.hero-cta { display: flex; gap: 14px; flex-wrap: wrap; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-block; font-weight: 700; font-size: 1rem;
  padding: 13px 24px; border-radius: 10px; cursor: pointer;
  border: 1px solid transparent; transition: transform .05s ease, background .15s ease;
}
.btn:hover { text-decoration: none; }
.btn:active { transform: translateY(1px); }
.btn-primary { background: var(--brand); color: #fff; }
.btn-primary:hover { background: var(--brand-dark); color: #fff; }
.btn-ghost { background: rgba(255,255,255,.08); color: #fff; border-color: rgba(255,255,255,.25); }
.btn-ghost:hover { background: rgba(255,255,255,.16); color: #fff; }
.btn-aff {
  background: var(--gold); color: #1a1303; box-shadow: 0 4px 14px rgba(245,158,11,.35);
}
.btn-aff:hover { background: #e08e07; color: #1a1303; }
.btn-block { display: block; text-align: center; }

/* ---------- Layout ---------- */
main { display: block; }
.section { padding: 64px 0; }
.section-alt { background: var(--bg-alt); }
.section-title { font-size: clamp(1.6rem, 3vw, 2.2rem); letter-spacing: -.02em; margin: 0 0 12px; }
.section-sub { color: var(--text-soft); font-size: 1.1rem; max-width: 640px; margin: 0 auto 40px; text-align: center; }
.center { text-align: center; }

/* ---------- Article ---------- */
.article-head { background: var(--bg-alt); border-bottom: 1px solid var(--border); padding: 40px 0 32px; }
.article-head h1 { font-size: clamp(1.8rem, 4vw, 2.6rem); line-height: 1.15; letter-spacing: -.02em; margin: 10px 0 14px; max-width: 860px; }
.article-meta { color: var(--muted); font-size: .92rem; display: flex; gap: 16px; flex-wrap: wrap; align-items: center; }
.article-meta .by { font-weight: 600; color: var(--text-soft); }

.prose { max-width: var(--readw); margin: 0 auto; padding: 40px 20px 64px; }
.prose h2 { font-size: 1.6rem; letter-spacing: -.01em; margin: 2.2em 0 .6em; line-height: 1.25; scroll-margin-top: 80px; }
.prose h3 { font-size: 1.25rem; margin: 1.8em 0 .5em; line-height: 1.3; scroll-margin-top: 80px; }
.prose p { margin: 0 0 1.2em; color: var(--text); }
.prose ul, .prose ol { margin: 0 0 1.4em; padding-left: 1.3em; }
.prose li { margin: .4em 0; }
.prose img { border-radius: var(--radius); margin: 1.5em 0; }
.prose strong { color: var(--text); }
.lead { font-size: 1.2rem; color: var(--text-soft); }

/* ---------- Breadcrumbs ---------- */
.crumbs { font-size: .85rem; color: var(--muted); }
.crumbs a { color: var(--muted); }
.crumbs a:hover { color: var(--brand); }

/* ---------- Table of contents ---------- */
.toc { background: var(--bg-alt); border: 1px solid var(--border); border-radius: var(--radius); padding: 20px 24px; margin: 0 0 32px; }
.toc strong { display: block; font-size: .8rem; text-transform: uppercase; letter-spacing: .08em; color: var(--muted); margin-bottom: 10px; }
.toc ol { margin: 0; padding-left: 1.2em; }
.toc li { margin: .3em 0; }

/* ---------- Tables ---------- */
.table-wrap { overflow-x: auto; margin: 1.6em 0; border: 1px solid var(--border); border-radius: var(--radius); }
table.cmp { width: 100%; border-collapse: collapse; font-size: .95rem; min-width: 560px; }
table.cmp th, table.cmp td { padding: 12px 14px; text-align: left; border-bottom: 1px solid var(--border); vertical-align: top; }
table.cmp thead th { background: var(--bg-dark); color: #fff; font-size: .82rem; text-transform: uppercase; letter-spacing: .04em; }
table.cmp tbody tr:nth-child(even) { background: var(--bg-alt); }
table.cmp tbody tr:hover { background: var(--brand-soft); }
table.cmp td:first-child { font-weight: 600; }

/* ---------- Cards ---------- */
.grid { display: grid; gap: 22px; }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.card {
  background: var(--bg); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 24px; box-shadow: var(--shadow); transition: transform .15s ease, box-shadow .15s ease;
}
.card:hover { transform: translateY(-3px); box-shadow: var(--shadow-lg); }
.card h3 { margin: 0 0 8px; font-size: 1.15rem; }
.card p { color: var(--text-soft); font-size: .96rem; margin: 0 0 14px; }
.card .tag { display: inline-block; font-size: .72rem; font-weight: 700; text-transform: uppercase; letter-spacing: .05em;
  color: var(--brand); background: var(--brand-soft); padding: 4px 10px; border-radius: 999px; margin-bottom: 12px; }
.card a.more { font-weight: 700; font-size: .92rem; }

/* ---------- Review / pick box ---------- */
.pick {
  border: 1px solid var(--border); border-radius: var(--radius); padding: 0; margin: 2em 0;
  box-shadow: var(--shadow); overflow: hidden;
}
.pick-top { display: flex; align-items: center; gap: 16px; padding: 18px 22px; background: var(--bg-alt); border-bottom: 1px solid var(--border); flex-wrap: wrap; }
.pick-rank { font-weight: 800; color: #fff; background: var(--brand); width: 38px; height: 38px; border-radius: 999px; display: grid; place-items: center; flex: none; }
.pick-top h3 { margin: 0; font-size: 1.2rem; flex: 1 1 200px; }
.pick-badge { font-size: .72rem; font-weight: 700; text-transform: uppercase; letter-spacing: .05em; padding: 5px 11px; border-radius: 999px; }
.badge-best { background: #dcfce7; color: #166534; }
.badge-value { background: #fef3c7; color: #92400e; }
.badge-free { background: #e0f2fe; color: #075985; }
.pick-body { padding: 20px 22px; }
.pick-body p { margin: 0 0 1em; }
.pick-stats { display: flex; gap: 22px; flex-wrap: wrap; margin: 4px 0 16px; font-size: .9rem; }
.pick-stats div span { display: block; color: var(--muted); font-size: .76rem; text-transform: uppercase; letter-spacing: .04em; }
.pick-stats div b { font-size: 1rem; }

/* ---------- Pros / Cons ---------- */
.proscons { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; margin: 1.6em 0; }
.pc { border-radius: var(--radius); padding: 18px 20px; border: 1px solid var(--border); }
.pc h4 { margin: 0 0 10px; font-size: 1rem; }
.pc.pros { background: #f0fdf4; border-color: #bbf7d0; }
.pc.cons { background: #fef2f2; border-color: #fecaca; }
.pc ul { margin: 0; padding-left: 1.1em; }
.pc li { margin: .35em 0; font-size: .95rem; }
.pc.pros li::marker { color: var(--good); }
.pc.cons li::marker { color: var(--bad); }

/* ---------- Callouts ---------- */
.note { border-left: 4px solid var(--brand); background: var(--brand-soft); padding: 14px 18px; border-radius: 8px; margin: 1.6em 0; font-size: .96rem; }
.note.warn { border-color: var(--gold); background: #fffbeb; }
.disclosure-inline { font-size: .85rem; color: var(--muted); background: var(--bg-alt); border: 1px solid var(--border); border-radius: 8px; padding: 10px 14px; margin: 0 0 24px; }

/* ---------- FAQ ---------- */
.faq details { border: 1px solid var(--border); border-radius: var(--radius-sm); margin: 10px 0; background: var(--bg); overflow: hidden; }
.faq summary { cursor: pointer; padding: 16px 18px; font-weight: 700; list-style: none; position: relative; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; position: absolute; right: 18px; top: 14px; font-size: 1.3rem; color: var(--brand); }
.faq details[open] summary::after { content: "–"; }
.faq details[open] summary { border-bottom: 1px solid var(--border); }
.faq .faq-a { padding: 14px 18px; color: var(--text-soft); }
.faq .faq-a p { margin: 0 0 .8em; }

/* ---------- CTA band ---------- */
.cta-band { background: linear-gradient(160deg, #15294d, #1d4ed8); color: #fff; border-radius: var(--radius); padding: 40px; text-align: center; margin: 2.4em 0; }
.cta-band h3 { color: #fff; margin: 0 0 10px; font-size: 1.5rem; }
.cta-band p { color: #c7d2e6; margin: 0 0 22px; }

/* ---------- Author box ---------- */
.author-box { display: flex; gap: 16px; align-items: flex-start; background: var(--bg-alt); border: 1px solid var(--border); border-radius: var(--radius); padding: 20px; margin: 2.4em 0; }
.author-box .avatar { width: 54px; height: 54px; border-radius: 999px; background: var(--brand); color: #fff; display: grid; place-items: center; font-weight: 800; font-size: 1.3rem; flex: none; }
.author-box h4 { margin: 0 0 4px; }
.author-box p { margin: 0; font-size: .92rem; color: var(--text-soft); }

/* ---------- Footer ---------- */
.site-footer { background: var(--bg-dark); color: #aab4c5; padding: 56px 0 28px; margin-top: 40px; font-size: .92rem; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 32px; margin-bottom: 36px; }
.site-footer h4 { color: #fff; font-size: .85rem; text-transform: uppercase; letter-spacing: .06em; margin: 0 0 14px; }
.site-footer a { color: #aab4c5; display: block; margin: 8px 0; }
.site-footer a:hover { color: #fff; }
.site-footer .logo { color: #fff; }
.footer-bottom { border-top: 1px solid #243049; padding-top: 22px; color: #7c879b; font-size: .85rem; }
.footer-disclosure { font-size: .82rem; color: #7c879b; margin-top: 10px; max-width: 760px; }

/* ---------- Internal link list ---------- */
.related { background: var(--bg-alt); border: 1px solid var(--border); border-radius: var(--radius); padding: 24px; margin: 2.4em 0; }
.related h3 { margin: 0 0 12px; font-size: 1.1rem; }
.related ul { margin: 0; padding-left: 1.1em; }
.related li { margin: .4em 0; }

/* ---------- Utility ---------- */
.mt0 { margin-top: 0; }
.text-muted { color: var(--muted); }
.small { font-size: .88rem; }

/* ---------- Responsive ---------- */
@media (max-width: 860px) {
  .grid-3 { grid-template-columns: 1fr 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 640px) {
  body { font-size: 17px; }
  .grid-3, .grid-2 { grid-template-columns: 1fr; }
  .proscons { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .main-nav { gap: 0; }
  .main-nav a { padding: 8px 9px; font-size: .85rem; }
  .hero { padding: 52px 0 44px; }
  .cta-band { padding: 28px 20px; }
}