/* Duofield landing — minimal, fast, mobile-first, system fonts only */

:root {
  --tg: #0088cc;
  --tg-dark: #006699;
  --bg: #ffffff;
  --fg: #0f172a;
  --fg-muted: #64748b;
  --border: #e2e8f0;
  --surface: #f8fafc;
  --surface-hover: #f1f5f9;
  --accent: #0088cc;
  --radius: 14px;
  --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.05);
  --shadow-md: 0 4px 16px rgba(15, 23, 42, 0.08);
  --max-width: 1100px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b0f17;
    --fg: #e2e8f0;
    --fg-muted: #94a3b8;
    --border: #1e293b;
    --surface: #111827;
    --surface-hover: #1e293b;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.4);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.5);
  }
}

* {
  box-sizing: border-box;
}

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

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, Roboto,
               'Helvetica Neue', Arial, 'Noto Sans', sans-serif,
               'Apple Color Emoji', 'Segoe UI Emoji';
  background: var(--bg);
  color: var(--fg);
  line-height: 1.6;
  font-size: 17px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

h1, h2, h3 {
  margin: 0 0 16px;
  line-height: 1.2;
  letter-spacing: -0.015em;
}

h1 { font-size: clamp(2rem, 5vw, 3.5rem); font-weight: 800; }
h2 { font-size: clamp(1.6rem, 3.5vw, 2.4rem); font-weight: 700; margin-bottom: 32px; }
h3 { font-size: 1.2rem; font-weight: 600; }

p { margin: 0 0 16px; }

a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.15s;
}
a:hover { color: var(--tg-dark); }

code {
  font-family: ui-monospace, SFMono-Regular, 'Cascadia Code', Menlo, monospace;
  background: var(--surface);
  padding: 1px 6px;
  border-radius: 4px;
  font-size: 0.9em;
}

.muted   { color: var(--fg-muted); }
.center  { text-align: center; margin-top: 24px; }
.accent  { color: var(--accent); }

/* ---- Header --------------------------------------------------------- */

header {
  border-bottom: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: saturate(180%) blur(12px);
  -webkit-backdrop-filter: saturate(180%) blur(12px);
  position: sticky;
  top: 0;
  z-index: 50;
}

@media (prefers-color-scheme: dark) {
  header { background: rgba(11, 15, 23, 0.85); }
}

header nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.logo {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--fg);
}
.logo:hover { color: var(--fg); }

.logo-icon { font-size: 1.4rem; }
.lang-switch {
  font-size: 0.9rem;
  padding: 6px 12px;
  border-radius: 999px;
  background: var(--surface);
  color: var(--fg);
}
.lang-switch:hover { background: var(--surface-hover); color: var(--fg); }

/* ---- Hero ----------------------------------------------------------- */

.hero {
  padding: 80px 0 64px;
  text-align: center;
  background:
    radial-gradient(60% 50% at 50% 0%, rgba(0, 136, 204, 0.10), transparent 60%);
}

.hero h1 br { display: block; }

.lead {
  font-size: clamp(1.05rem, 1.5vw, 1.25rem);
  color: var(--fg-muted);
  max-width: 640px;
  margin: 0 auto 32px;
}

.cta-row {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  margin-bottom: 32px;
}

.cta-note {
  color: var(--fg-muted);
  font-size: 0.9rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 14px 28px;
  border-radius: var(--radius);
  font-weight: 600;
  font-size: 1rem;
  text-decoration: none;
  transition: transform 0.15s, box-shadow 0.15s, background 0.15s;
  cursor: pointer;
}

.btn-primary {
  background: var(--tg);
  color: white;
  box-shadow: var(--shadow-md);
}
.btn-primary:hover {
  background: var(--tg-dark);
  color: white;
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(0, 136, 204, 0.3);
}

.btn-large {
  padding: 18px 36px;
  font-size: 1.1rem;
}

.tg-icon { flex-shrink: 0; }

.trust {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 16px 24px;
  color: var(--fg-muted);
  font-size: 0.9rem;
}

/* ---- Features ------------------------------------------------------- */

.features { padding: 80px 0; }

.grid-3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

.feature {
  background: var(--surface);
  padding: 28px 24px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  transition: transform 0.2s, box-shadow 0.2s;
}
.feature:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.feature-icon {
  font-size: 2rem;
  margin-bottom: 12px;
}

.feature h3 { margin-bottom: 8px; }
.feature p {
  margin: 0;
  color: var(--fg-muted);
  font-size: 0.95rem;
}

/* ---- How it works --------------------------------------------------- */

.how { padding: 80px 0; background: var(--surface); }

.steps {
  list-style: none;
  padding: 0;
  margin: 0 auto 32px;
  max-width: 720px;
  display: grid;
  gap: 28px;
}

.steps li {
  background: var(--bg);
  padding: 28px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  position: relative;
  padding-left: 80px;
}

.step-num {
  position: absolute;
  left: 24px;
  top: 24px;
  width: 36px;
  height: 36px;
  border-radius: 999px;
  background: var(--tg);
  color: white;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
}

.steps p { margin: 0; color: var(--fg-muted); font-size: 0.95rem; }

/* ---- FAQ ------------------------------------------------------------ */

.faq { padding: 80px 0; }

.faq details {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 24px;
  margin-bottom: 12px;
  transition: background 0.15s;
}
.faq details:hover { background: var(--surface-hover); }

.faq summary {
  cursor: pointer;
  font-weight: 600;
  font-size: 1.05rem;
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.faq summary::after {
  content: '+';
  font-size: 1.4rem;
  color: var(--fg-muted);
  transition: transform 0.2s;
}
.faq details[open] summary::after { content: '−'; }

.faq summary::-webkit-details-marker { display: none; }

.faq details p {
  margin: 16px 0 0;
  color: var(--fg-muted);
}

/* ---- Final CTA ------------------------------------------------------ */

.cta-final {
  padding: 80px 0;
  text-align: center;
  background: linear-gradient(135deg, var(--tg) 0%, #005580 100%);
  color: white;
}
.cta-final h2 { color: white; margin-bottom: 16px; }
.cta-final p {
  color: rgba(255, 255, 255, 0.9);
  margin-bottom: 32px;
  font-size: 1.1rem;
}
.cta-final .btn-primary {
  background: white;
  color: var(--tg);
}
.cta-final .btn-primary:hover {
  background: #f0f9ff;
  color: var(--tg);
}

/* ---- Footer --------------------------------------------------------- */

footer {
  border-top: 1px solid var(--border);
  padding: 40px 0;
  font-size: 0.9rem;
}

.footer-row {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
}

.footer-nav {
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
}
.footer-nav a {
  color: var(--fg-muted);
}
.footer-nav a:hover { color: var(--fg); }

.copyright {
  margin: 24px 0 0;
  color: var(--fg-muted);
  font-size: 0.85rem;
}

/* ---- Small screens -------------------------------------------------- */

@media (max-width: 640px) {
  .hero { padding: 56px 0 48px; }
  .features, .how, .faq, .cta-final { padding: 56px 0; }
  .btn { width: 100%; justify-content: center; max-width: 360px; }
  .footer-row { flex-direction: column; align-items: flex-start; }
}

/* ---- Accessibility -------------------------------------------------- */

:focus-visible {
  outline: 2px solid var(--tg);
  outline-offset: 3px;
  border-radius: 4px;
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* ---- Long-form prose (about, faq, blog articles) -------------------- */

.prose {
  max-width: 720px;          /* ~66ch — a comfortable reading measure */
  margin: 0 auto;
  padding: 56px 24px 80px;
  font-size: 1.0625rem;
  line-height: 1.75;
}

.prose h1 {
  font-size: clamp(2rem, 4.5vw, 2.9rem);
  margin-bottom: 14px;
}
.prose h2 {
  font-size: clamp(1.45rem, 2.6vw, 1.95rem);
  margin: 52px 0 18px;
  scroll-margin-top: 84px;   /* clear the sticky header on anchor jumps */
  position: relative;
}
.prose h2::before {          /* short editorial accent rule above each section */
  content: "";
  position: absolute;
  top: -16px;
  left: 0;
  width: 36px;
  height: 3px;
  border-radius: 2px;
  background: var(--tg);
}
.prose h3 { margin: 34px 0 10px; scroll-margin-top: 84px; }
.prose p { margin: 0 0 20px; }
.prose p, .prose li { color: var(--fg); }
.prose strong { font-weight: 700; }

.prose p a:not(.btn), .prose li a:not(.btn) {
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 2px;
  text-decoration-color: color-mix(in srgb, var(--accent) 40%, transparent);
}
.prose p a:not(.btn):hover, .prose li a:not(.btn):hover {
  text-decoration-color: var(--accent);
}

.prose ul, .prose ol { padding-left: 24px; margin: 0 0 22px; }
.prose li { margin-bottom: 10px; padding-left: 4px; }
.prose li::marker { color: var(--tg); font-weight: 700; }

.prose .lead {
  font-size: clamp(1.15rem, 1.7vw, 1.35rem);
  line-height: 1.6;
  color: var(--fg-muted);
  margin: 0 0 8px;
}

.breadcrumb {
  font-size: 0.82rem;
  letter-spacing: 0.01em;
  color: var(--fg-muted);
  margin-bottom: 20px;
}
.breadcrumb a { color: var(--fg-muted); }
.breadcrumb a:hover { color: var(--accent); }

.post-meta {
  color: var(--fg-muted);
  font-size: 0.85rem;
  letter-spacing: 0.02em;
  margin: 0 0 36px;
}

.callout {
  background: var(--surface);
  border: 1px solid var(--border);
  border-left: 3px solid var(--tg);
  border-radius: var(--radius);
  padding: 20px 24px;
  margin: 32px 0;
}
.callout p:last-child { margin-bottom: 0; }

/* Prev/next nav at the foot of an article */
.post-nav {
  margin-top: 56px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
  font-size: 0.95rem;
}

/* Homepage informational sections (text-led, not cards) */
.section-text { padding: 72px 0; }
.section-text .container { max-width: 820px; }
.section-text p { color: var(--fg-muted); }
.section-text.alt { background: var(--surface); }

/* Blog index — list of posts */
.post-list {
  display: grid;
  gap: 18px;
  max-width: 720px;
  margin: 0 auto;
}
.post-card {
  display: block;
  position: relative;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 26px 56px 26px 26px;
  transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s;
}
.post-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  border-color: color-mix(in srgb, var(--tg) 45%, var(--border));
}
.post-card h3 { margin-bottom: 8px; color: var(--fg); transition: color 0.2s; }
.post-card:hover h3 { color: var(--tg); }
.post-card p { margin: 0; color: var(--fg-muted); font-size: 0.95rem; }
.post-card-meta {
  display: block;
  margin-top: 14px;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--fg-muted);
}
.post-card::after {       /* arrow affordance that nudges on hover */
  content: "\2192";
  position: absolute;
  right: 24px;
  top: 26px;
  color: var(--tg);
  font-size: 1.2rem;
  opacity: 0.6;
  transition: transform 0.2s, opacity 0.2s;
}
.post-card:hover::after { transform: translateX(4px); opacity: 1; }

.cta-inline {
  text-align: center;
  margin: 44px 0 8px;
}