/* =========================================================
   DIGIPIN Hub — design system
   Clean, minimal, responsive. Mobile-first.
   Change the accent color in --accent to rebrand.
   ========================================================= */

:root {
  /* Colors */
  --bg: #ffffff;
  --bg-soft: #f8fafc;
  --bg-card: #ffffff;
  --text: #0f172a;
  --text-soft: #334155;
  --text-muted: #64748b;
  --border: #e2e8f0;
  --border-soft: #f1f5f9;
  --accent: #4338ca;          /* deep indigo */
  --accent-hover: #3730a3;
  --accent-soft: #eef2ff;
  --warning: #b45309;
  --warning-soft: #fffbeb;
  --success: #15803d;

  /* Typography */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, "Noto Sans", sans-serif, "Apple Color Emoji",
    "Segoe UI Emoji";
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;

  /* Scale */
  --container: 1120px;
  --container-narrow: 760px;
  --radius: 12px;
  --radius-sm: 8px;
  --radius-lg: 20px;
  --shadow-sm: 0 1px 2px rgba(15, 23, 42, .05);
  --shadow: 0 4px 12px rgba(15, 23, 42, .06);
  --shadow-lg: 0 10px 30px rgba(15, 23, 42, .08);

  /* Spacing */
  --gap-1: .25rem;
  --gap-2: .5rem;
  --gap-3: .75rem;
  --gap-4: 1rem;
  --gap-5: 1.5rem;
  --gap-6: 2rem;
  --gap-7: 3rem;
  --gap-8: 4rem;
  --gap-9: 6rem;
}

/* =========================================================
   Reset
   ========================================================= */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 17px;
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
img, svg { max-width: 100%; height: auto; display: block; }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
button { font-family: inherit; cursor: pointer; }
hr { border: 0; border-top: 1px solid var(--border); margin: var(--gap-6) 0; }

/* =========================================================
   Typography
   ========================================================= */
h1, h2, h3, h4, h5 {
  margin: 0 0 var(--gap-4);
  line-height: 1.2;
  font-weight: 700;
  letter-spacing: -.02em;
  color: var(--text);
}
h1 { font-size: clamp(2rem, 5vw, 3rem); }
h2 { font-size: clamp(1.5rem, 3.5vw, 2rem); margin-top: var(--gap-7); }
h3 { font-size: 1.25rem; margin-top: var(--gap-6); }
h4 { font-size: 1.05rem; margin-top: var(--gap-5); }
p { margin: 0 0 var(--gap-4); color: var(--text-soft); }
.lead { font-size: 1.15rem; color: var(--text-soft); }
small { color: var(--text-muted); }
code {
  font-family: var(--font-mono);
  font-size: .92em;
  background: var(--bg-soft);
  padding: .15em .4em;
  border-radius: 4px;
  border: 1px solid var(--border-soft);
}

/* =========================================================
   Layout primitives
   ========================================================= */
.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 var(--gap-5);
}
.container-narrow {
  max-width: var(--container-narrow);
  margin: 0 auto;
  padding: 0 var(--gap-5);
}
.section { padding: var(--gap-8) 0; }
.section-sm { padding: var(--gap-6) 0; }
.section-soft { background: var(--bg-soft); }

/* =========================================================
   Navigation
   ========================================================= */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255,255,255,.92);
  backdrop-filter: saturate(180%) blur(10px);
  -webkit-backdrop-filter: saturate(180%) blur(10px);
  border-bottom: 1px solid var(--border);
}
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--gap-2);
  font-weight: 800;
  font-size: 1.1rem;
  color: var(--text);
  letter-spacing: -.02em;
}
.brand:hover { text-decoration: none; }
.brand-mark {
  width: 28px; height: 28px;
  border-radius: 7px;
  background: var(--accent);
  color: #fff;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: .8rem;
  font-weight: 800;
}
.nav-links {
  display: flex;
  align-items: center;
  gap: var(--gap-6);
  list-style: none;
  margin: 0;
  padding: 0;
}
.nav-links a {
  color: var(--text-soft);
  font-size: .95rem;
  font-weight: 500;
}
.nav-links a:hover { color: var(--accent); text-decoration: none; }
.nav-links a.is-active { color: var(--text); }

.nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--border);
  border-radius: 8px;
  width: 40px;
  height: 40px;
  align-items: center;
  justify-content: center;
}
.nav-toggle span {
  display: block;
  width: 18px;
  height: 2px;
  background: var(--text);
  position: relative;
}
.nav-toggle span::before,
.nav-toggle span::after {
  content: "";
  position: absolute;
  left: 0;
  width: 18px;
  height: 2px;
  background: var(--text);
}
.nav-toggle span::before { top: -6px; }
.nav-toggle span::after  { top:  6px; }

@media (max-width: 820px) {
  .nav-toggle { display: inline-flex; }
  .nav-links {
    position: absolute;
    top: 64px;
    left: 0; right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: var(--bg);
    border-bottom: 1px solid var(--border);
    padding: var(--gap-3) var(--gap-5);
    display: none;
  }
  .nav-links.is-open { display: flex; }
  .nav-links a {
    padding: var(--gap-3) 0;
    border-bottom: 1px solid var(--border-soft);
    font-size: 1rem;
  }
  .nav-links li:last-child a { border-bottom: 0; }
}

/* =========================================================
   Buttons
   ========================================================= */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--gap-2);
  padding: .75rem 1.25rem;
  font-size: .95rem;
  font-weight: 600;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  text-decoration: none;
  transition: background .15s ease, color .15s ease, border-color .15s ease;
  line-height: 1;
}
.btn-primary {
  background: var(--accent);
  color: #fff;
}
.btn-primary:hover { background: var(--accent-hover); text-decoration: none; color: #fff; }
.btn-secondary {
  background: var(--bg);
  color: var(--text);
  border-color: var(--border);
}
.btn-secondary:hover { border-color: var(--text); text-decoration: none; }
.btn-lg { padding: 1rem 1.6rem; font-size: 1rem; }

/* =========================================================
   Hero
   ========================================================= */
.hero {
  padding: var(--gap-9) 0 var(--gap-8);
  text-align: center;
  background:
    radial-gradient(60% 80% at 50% 0%, var(--accent-soft) 0%, transparent 60%),
    var(--bg);
}
.hero h1 { max-width: 18ch; margin-left: auto; margin-right: auto; }
.hero .lead { max-width: 56ch; margin: 0 auto var(--gap-5); }
.hero-ctas {
  display: inline-flex;
  flex-wrap: wrap;
  gap: var(--gap-3);
  justify-content: center;
}
.eyebrow {
  display: inline-block;
  font-size: .8rem;
  font-weight: 700;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--accent);
  background: var(--accent-soft);
  padding: .35rem .7rem;
  border-radius: 999px;
  margin-bottom: var(--gap-4);
}

/* =========================================================
   Cards & grids
   ========================================================= */
.grid {
  display: grid;
  gap: var(--gap-5);
}
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
@media (max-width: 820px) {
  .grid-3, .grid-2 { grid-template-columns: 1fr; }
}

.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: var(--gap-5);
  transition: border-color .15s ease, transform .15s ease, box-shadow .15s ease;
  display: flex;
  flex-direction: column;
}
.card:hover { border-color: var(--text-muted); }
a.card { color: var(--text); }
a.card:hover { text-decoration: none; box-shadow: var(--shadow); }
.card h3 { margin-top: 0; font-size: 1.15rem; }
.card p { margin-bottom: 0; font-size: .95rem; }
.card .meta {
  margin-top: var(--gap-4);
  font-size: .85rem;
  color: var(--text-muted);
}
.card-icon {
  width: 44px; height: 44px;
  border-radius: 10px;
  background: var(--accent-soft);
  color: var(--accent);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  margin-bottom: var(--gap-4);
  font-weight: 700;
}

/* =========================================================
   Article / prose
   ========================================================= */
.article {
  padding: var(--gap-7) 0 var(--gap-8);
}
.article header { margin-bottom: var(--gap-6); }
.article header .eyebrow { background: transparent; padding: 0; }
.article-meta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--gap-4);
  font-size: .9rem;
  color: var(--text-muted);
  margin-top: var(--gap-3);
}
.article-meta span::before { content: "·"; margin-right: var(--gap-4); }
.article-meta span:first-child::before { content: ""; margin: 0; }

.prose {
  font-size: 1.05rem;
  line-height: 1.75;
}
.prose h2 { margin-top: var(--gap-7); }
.prose h3 { margin-top: var(--gap-6); }
.prose ul, .prose ol {
  padding-left: 1.4rem;
  margin: 0 0 var(--gap-4);
  color: var(--text-soft);
}
.prose li { margin-bottom: var(--gap-2); }
.prose blockquote {
  margin: var(--gap-5) 0;
  padding: var(--gap-4) var(--gap-5);
  border-left: 3px solid var(--accent);
  background: var(--accent-soft);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--text);
  font-style: normal;
}
.prose blockquote p:last-child { margin-bottom: 0; }
.prose table {
  width: 100%;
  border-collapse: collapse;
  margin: var(--gap-5) 0;
  font-size: .95rem;
}
.prose th, .prose td {
  text-align: left;
  padding: .75rem 1rem;
  border-bottom: 1px solid var(--border);
}
.prose th { background: var(--bg-soft); font-weight: 600; }

/* Breadcrumb */
.breadcrumb {
  font-size: .85rem;
  color: var(--text-muted);
  margin-bottom: var(--gap-4);
}
.breadcrumb a { color: var(--text-muted); }
.breadcrumb a:hover { color: var(--accent); }
.breadcrumb span { margin: 0 .35rem; }

/* =========================================================
   FAQ accordion
   ========================================================= */
.faq-group { margin-bottom: var(--gap-6); }
.faq-group h2 { font-size: 1.3rem; margin-bottom: var(--gap-4); }
.faq details {
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: var(--gap-4) var(--gap-5);
  margin-bottom: var(--gap-3);
  background: var(--bg);
}
.faq details[open] { border-color: var(--accent); background: var(--bg-soft); }
.faq summary {
  cursor: pointer;
  font-weight: 600;
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--gap-4);
  color: var(--text);
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after {
  content: "+";
  font-size: 1.4rem;
  color: var(--text-muted);
  font-weight: 400;
  transition: transform .15s ease;
}
.faq details[open] summary::after {
  content: "−";
  color: var(--accent);
}
.faq details > *:not(summary) {
  margin-top: var(--gap-3);
  color: var(--text-soft);
}

/* =========================================================
   Glossary
   ========================================================= */
.glossary-nav {
  display: flex;
  flex-wrap: wrap;
  gap: var(--gap-2);
  margin-bottom: var(--gap-6);
  padding: var(--gap-4);
  background: var(--bg-soft);
  border-radius: var(--radius);
  border: 1px solid var(--border);
}
.glossary-nav a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 32px;
  height: 32px;
  padding: 0 .5rem;
  border-radius: 6px;
  font-size: .9rem;
  font-weight: 600;
  background: var(--bg);
  border: 1px solid var(--border);
  color: var(--text-soft);
}
.glossary-nav a:hover { background: var(--accent); color: #fff; border-color: var(--accent); text-decoration: none; }

.glossary-entry {
  padding: var(--gap-5) 0;
  border-bottom: 1px solid var(--border-soft);
  scroll-margin-top: 80px;
}
.glossary-entry h3 { margin: 0 0 var(--gap-2); font-size: 1.2rem; }
.glossary-entry p { margin: 0; color: var(--text-soft); }

/* =========================================================
   Ad slots — drop-in containers for AdSense / Ezoic / Mediavine
   Wrap each ad unit in <div class="ad-slot"> with a label.
   ========================================================= */
.ad-slot {
  margin: var(--gap-6) auto;
  padding: var(--gap-4);
  background: var(--bg-soft);
  border: 1px dashed var(--border);
  border-radius: var(--radius-sm);
  text-align: center;
  min-height: 100px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  max-width: 728px;
}
.ad-slot::before {
  content: "Advertisement";
  display: block;
  font-size: .7rem;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: var(--gap-2);
  font-weight: 600;
}
.ad-slot--inline { max-width: 100%; min-height: 90px; }
.ad-slot--sticky-mobile { display: none; }
@media (max-width: 820px) {
  .ad-slot--desktop-only { display: none; }
}

/* =========================================================
   Newsletter / CTAs
   ========================================================= */
.cta-block {
  background: var(--text);
  color: #fff;
  border-radius: var(--radius-lg);
  padding: var(--gap-7) var(--gap-6);
  text-align: center;
  margin: var(--gap-7) 0;
}
.cta-block h2 { color: #fff; margin-top: 0; }
.cta-block p { color: rgba(255,255,255,.75); max-width: 50ch; margin: 0 auto var(--gap-5); }
.cta-block .form-inline { max-width: 480px; margin: 0 auto; }

.form-inline {
  display: flex;
  gap: var(--gap-2);
  flex-wrap: wrap;
}
.form-inline input[type="email"] {
  flex: 1 1 240px;
  padding: .8rem 1rem;
  font-size: 1rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: var(--bg);
  color: var(--text);
  font-family: inherit;
}
.form-inline input[type="email"]:focus {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

/* =========================================================
   Footer
   ========================================================= */
.site-footer {
  background: var(--bg-soft);
  border-top: 1px solid var(--border);
  padding: var(--gap-7) 0 var(--gap-5);
  margin-top: var(--gap-8);
  font-size: .9rem;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--gap-6);
  margin-bottom: var(--gap-6);
}
.footer-grid h4 {
  font-size: .8rem;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--text-muted);
  font-weight: 700;
  margin: 0 0 var(--gap-3);
}
.footer-grid ul { list-style: none; padding: 0; margin: 0; }
.footer-grid li { margin-bottom: var(--gap-2); }
.footer-grid a { color: var(--text-soft); }
.footer-grid a:hover { color: var(--accent); }
.footer-bottom {
  padding-top: var(--gap-4);
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--gap-3);
  color: var(--text-muted);
  font-size: .85rem;
}
.footer-bottom a { color: var(--text-muted); }
@media (max-width: 820px) {
  .footer-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 520px) {
  .footer-grid { grid-template-columns: 1fr; }
}

/* =========================================================
   Utilities
   ========================================================= */
.text-center { text-align: center; }
.mt-0 { margin-top: 0; }
.mb-0 { margin-bottom: 0; }
.mt-6 { margin-top: var(--gap-6); }
.mb-6 { margin-bottom: var(--gap-6); }
.flex { display: flex; }
.flex-wrap { flex-wrap: wrap; }
.gap-3 { gap: var(--gap-3); }
.gap-4 { gap: var(--gap-4); }
.tag {
  display: inline-block;
  font-size: .75rem;
  letter-spacing: .06em;
  font-weight: 600;
  text-transform: uppercase;
  color: var(--accent);
  background: var(--accent-soft);
  padding: .2rem .55rem;
  border-radius: 4px;
}

/* Skip link for accessibility */
.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--text);
  color: #fff;
  padding: .5rem 1rem;
  z-index: 100;
}
.skip-link:focus { left: 8px; top: 8px; text-decoration: none; }