/* xbrain marketing site — shared styles */
/* Accent color: #7C3AED (violet) */
/* Complements TailwindCSS CDN — only custom patterns here */

/* ============================================================
   1. CSS Variables
   ============================================================ */
:root {
  --violet: #7C3AED;
  --violet-light: #EDE9FE;
  --violet-dark: #5B21B6;
  --gray-900: #111827;
  --gray-700: #374151;
  --gray-600: #4B5563;
  --gray-500: #6B7280;
  --gray-400: #9CA3AF;
  --gray-200: #E5E7EB;
  --gray-100: #F3F4F6;
  --gray-50: #F9FAFB;
  --white: #FFFFFF;
}

/* ============================================================
   2. Base reset
   ============================================================ */
*, *::before, *::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  color: var(--gray-900);
  background: var(--white);
  line-height: 1.6;
  margin: 0;
}

/* ============================================================
   3. Nav — .xb-nav
   ============================================================ */
.xb-nav {
  background: var(--white);
  border-bottom: 1px solid var(--gray-200);
  height: 64px;
  position: sticky;
  top: 0;
  z-index: 50;
  width: 100%;
}

.xb-nav__inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.xb-nav__logo {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--violet);
  text-decoration: none;
  letter-spacing: -0.025em;
}

.xb-nav__logo:hover {
  color: var(--violet-dark);
}

.xb-nav__links {
  display: flex;
  align-items: center;
  gap: 8px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.xb-nav__link {
  display: inline-block;
  padding: 8px 16px;
  color: var(--gray-600);
  text-decoration: none;
  font-size: 0.9375rem;
  font-weight: 500;
  border-radius: 6px;
  transition: color 150ms ease, background 150ms ease;
}

.xb-nav__link:hover {
  color: var(--violet);
  background: var(--violet-light);
}

/* ============================================================
   4. Buttons — .btn-primary / .btn-secondary
   ============================================================ */
.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: #7C3AED;
  color: var(--white);
  padding: 12px 24px;
  border-radius: 8px;
  font-weight: 600;
  font-size: 0.9375rem;
  text-decoration: none;
  border: 2px solid #7C3AED;
  cursor: pointer;
  transition: background 200ms ease, border-color 200ms ease, transform 100ms ease;
  white-space: nowrap;
}

.btn-primary:hover {
  background: var(--violet-dark);
  border-color: var(--violet-dark);
  transform: translateY(-1px);
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: transparent;
  color: #7C3AED;
  padding: 12px 24px;
  border-radius: 8px;
  font-weight: 600;
  font-size: 0.9375rem;
  text-decoration: none;
  border: 2px solid #7C3AED;
  cursor: pointer;
  transition: background 200ms ease, color 200ms ease, transform 100ms ease;
  white-space: nowrap;
}

.btn-secondary:hover {
  background: var(--violet-light);
  transform: translateY(-1px);
}

/* ============================================================
   5. Footer — .xb-footer
   ============================================================ */
.xb-footer {
  background: var(--gray-900);
  color: var(--white);
  padding: 48px 0 32px;
}

.xb-footer__inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

.xb-footer__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 48px;
  margin-bottom: 40px;
}

@media (max-width: 640px) {
  .xb-footer__grid {
    grid-template-columns: 1fr;
    gap: 32px;
  }
}

.xb-footer__col-title {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--gray-400);
  margin: 0 0 16px;
}

.xb-footer__links {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.xb-footer__link {
  color: var(--gray-400);
  text-decoration: none;
  font-size: 0.9375rem;
  transition: color 150ms ease;
}

.xb-footer__link:hover {
  color: var(--white);
}

.xb-footer__bottom {
  border-top: 1px solid #374151;
  padding-top: 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

.xb-footer__copyright {
  color: var(--gray-500);
  font-size: 0.875rem;
}

/* ============================================================
   6. Utility helpers
   ============================================================ */
.container-xl {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}