/* StackPay AI — clean, fast, mobile-friendly, conversion-focused */
:root {
  --bg: #0b1220;
  --surface: #121a2b;
  --surface-2: #1a2438;
  --text: #e8eef9;
  --muted: #9aa8c3;
  --accent: #5b8cff;
  --accent-2: #3dd6c6;
  --warn: #f0c14b;
  --border: #2a3650;
  --radius: 12px;
  --shadow: 0 8px 30px rgba(0, 0, 0, 0.35);
  --max: 880px;
  --font: "Inter", system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  font-size: 1.05rem;
}

a { color: var(--accent-2); text-decoration: none; }
a:hover { text-decoration: underline; }

.wrap { width: min(100% - 2rem, var(--max)); margin-inline: auto; }

/* Header */
.site-header {
  position: sticky; top: 0; z-index: 20;
  background: rgba(11, 18, 32, 0.92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.nav {
  display: flex; align-items: center; justify-content: space-between;
  gap: 1rem; padding: 0.85rem 0; flex-wrap: wrap;
}
.brand { display: flex; flex-direction: column; gap: 0.1rem; }
.brand strong { font-size: 1.15rem; letter-spacing: -0.02em; }
.brand span { font-size: 0.8rem; color: var(--muted); }
.nav-links { display: flex; gap: 0.85rem; flex-wrap: wrap; font-size: 0.92rem; }
.nav-links a { color: var(--text); opacity: 0.9; }
.nav-links a:hover { color: var(--accent-2); }

/* Hero */
.hero {
  padding: 2.5rem 0 1.5rem;
  border-bottom: 1px solid var(--border);
  background:
    radial-gradient(ellipse at 20% 0%, rgba(91, 140, 255, 0.18), transparent 50%),
    radial-gradient(ellipse at 80% 20%, rgba(61, 214, 198, 0.12), transparent 45%);
}
.hero h1 {
  font-size: clamp(1.75rem, 4vw, 2.4rem);
  line-height: 1.2; letter-spacing: -0.03em; margin: 0 0 0.75rem;
}
.hero p { color: var(--muted); margin: 0 0 1.25rem; max-width: 40rem; }
.badge {
  display: inline-block; font-size: 0.75rem; font-weight: 600;
  color: var(--warn); background: rgba(240, 193, 75, 0.12);
  border: 1px solid rgba(240, 193, 75, 0.35);
  padding: 0.25rem 0.6rem; border-radius: 999px; margin-bottom: 0.85rem;
}

/* Buttons / CTAs */
.btn {
  display: inline-block; padding: 0.7rem 1.15rem; border-radius: 10px;
  font-weight: 650; border: 1px solid transparent; text-decoration: none !important;
  transition: transform 0.12s ease, background 0.12s ease;
}
.btn:hover { transform: translateY(-1px); }
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: #4a7af0; }
.btn-secondary {
  background: var(--surface-2); color: var(--text);
  border-color: var(--border);
}
.btn-row { display: flex; flex-wrap: wrap; gap: 0.65rem; margin: 1rem 0 1.25rem; }

/* Cards */
.grid {
  display: grid; gap: 1rem;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  padding: 1.75rem 0 0.5rem;
}
.card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 1.15rem 1.2rem; box-shadow: var(--shadow);
}
.card h2, .card h3 { margin: 0 0 0.4rem; font-size: 1.1rem; }
.card p { margin: 0 0 0.85rem; color: var(--muted); font-size: 0.95rem; }
.card .meta { font-size: 0.8rem; color: var(--muted); margin-bottom: 0.5rem; }

/* Article */
.article { padding: 1.75rem 0 3rem; }
.article header { margin-bottom: 1.5rem; }
.article h1 {
  font-size: clamp(1.6rem, 3.5vw, 2.1rem);
  line-height: 1.25; letter-spacing: -0.02em; margin: 0 0 0.5rem;
}
.article .dek { color: var(--muted); margin: 0; }
.article h2 {
  margin: 2rem 0 0.75rem; font-size: 1.35rem;
  border-top: 1px solid var(--border); padding-top: 1.5rem;
}
.article h3 { margin: 1.35rem 0 0.5rem; font-size: 1.1rem; }
.article ul, .article ol { padding-left: 1.2rem; }
.article li { margin: 0.35rem 0; }
.disclosure {
  background: var(--surface-2); border-left: 3px solid var(--warn);
  padding: 0.85rem 1rem; border-radius: 0 8px 8px 0;
  font-size: 0.92rem; color: var(--muted); margin: 1rem 0 1.5rem;
}

/* Tables */
.table-wrap { overflow-x: auto; margin: 1rem 0 1.5rem; border-radius: var(--radius);
  border: 1px solid var(--border); }
table {
  width: 100%; border-collapse: collapse; font-size: 0.92rem;
  background: var(--surface);
}
th, td {
  text-align: left; padding: 0.7rem 0.85rem;
  border-bottom: 1px solid var(--border); vertical-align: top;
}
th { background: var(--surface-2); color: var(--text); font-weight: 650; }
tr:last-child td { border-bottom: none; }

.cta-box {
  background: linear-gradient(135deg, rgba(91,140,255,0.15), rgba(61,214,198,0.1));
  border: 1px solid var(--border); border-radius: var(--radius);
  padding: 1.25rem 1.35rem; margin: 1.75rem 0;
}
.cta-box h2 { border: none; padding: 0; margin: 0 0 0.5rem; font-size: 1.2rem; }

.related {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 1.1rem 1.25rem; margin-top: 2rem;
}
.related ul { margin: 0.4rem 0 0; }

/* Footer */
.site-footer {
  border-top: 1px solid var(--border); padding: 1.75rem 0 2.5rem;
  color: var(--muted); font-size: 0.88rem;
}
.site-footer strong { color: var(--text); }
.footer-disclosure {
  margin-top: 0.75rem; padding-top: 0.75rem;
  border-top: 1px dashed var(--border);
}

@media (max-width: 560px) {
  body { font-size: 1rem; }
  .nav-links { width: 100%; }
  th, td { padding: 0.55rem 0.6rem; }
}