/* ===========================
   APLEXCUB STUDENT TOOLS
   layout.css — Header, Footer, Hero
   =========================== */

/* --- Header --- */
.header {
  position: sticky;
  top: 0;
  z-index: 500;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  height: var(--header-height);
  transition: box-shadow var(--transition-fast);
}
.header.scrolled { box-shadow: var(--shadow-md); }

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-height);
  gap: var(--space-4);
}

.nav-desktop {
  display: none;
  align-items: center;
  gap: var(--space-1);
}

@media (min-width: 1024px) {
  .nav-desktop { display: flex; }
  .nav-mobile-btn { display: none; }
}

.nav-link {
  padding: 0.4rem 0.75rem;
  border-radius: var(--radius-sm);
  font-family: var(--font-primary);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-muted);
  text-decoration: none;
  transition: all var(--transition-fast);
}
.nav-link:hover, .nav-link.active {
  color: var(--color-primary);
  background: rgba(37, 99, 235, 0.06);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

/* --- Mobile Menu --- */
.mobile-menu {
  display: none;
  background: var(--color-bg);
  border-top: 1px solid var(--color-border);
  padding: var(--space-4) 0;
}
.mobile-menu.open { display: block; }

.mobile-nav-link {
  display: block;
  padding: var(--space-3) var(--space-6);
  font-family: var(--font-primary);
  font-size: var(--text-base);
  font-weight: 500;
  color: var(--color-text);
  text-decoration: none;
  transition: all var(--transition-fast);
}
.mobile-nav-link:hover {
  color: var(--color-primary);
  background: var(--color-surface);
}

/* --- Hero --- */
.hero {
  background: linear-gradient(180deg, var(--color-surface) 0%, var(--color-bg) 100%);
  padding: var(--space-20) 0 var(--space-16);
  text-align: center;
}

.hero-content {
  max-width: 680px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: 0.35rem 0.875rem;
  border-radius: var(--radius-full);
  background: rgba(6, 182, 212, 0.08);
  border: 1px solid rgba(6, 182, 212, 0.2);
  font-size: var(--text-xs);
  font-weight: 600;
  color: var(--color-accent);
  margin-bottom: var(--space-5);
  letter-spacing: 0.02em;
  text-transform: uppercase;
}

.hero-heading {
  font-size: clamp(var(--text-3xl), 5vw, var(--text-5xl));
  font-weight: 700;
  line-height: 1.1;
  margin-bottom: var(--space-5);
  letter-spacing: -0.02em;
}

.hero-desc {
  font-size: var(--text-lg);
  color: var(--color-text-muted);
  max-width: 520px;
  line-height: 1.7;
  margin-bottom: var(--space-2);
}

.hero-cta {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  flex-wrap: wrap;
  justify-content: center;
  margin-top: var(--space-4);
}

.hero-stats {
  display: flex;
  align-items: center;
  gap: var(--space-8);
  margin-top: var(--space-10);
  padding-top: var(--space-8);
  border-top: 1px solid var(--color-border);
}

.stat { text-align: center; }
.stat-number {
  display: block;
  font-family: var(--font-primary);
  font-size: var(--text-2xl);
  font-weight: 700;
  color: var(--color-primary);
}
.stat-label {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}
.stat-divider {
  width: 1px;
  height: 40px;
  background: var(--color-border);
}

/* --- Footer --- */
.footer {
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding: var(--space-16) 0 var(--space-8);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-10);
  margin-bottom: var(--space-12);
}

@media (min-width: 640px) {
  .footer-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (min-width: 1024px) {
  .footer-grid { grid-template-columns: 2fr 1fr 1fr 1fr; }
}

.footer-brand .footer-tagline {
  font-family: var(--font-primary);
  font-size: var(--text-base);
  font-weight: 600;
  margin-top: var(--space-4);
  margin-bottom: var(--space-2);
}

.footer-sub {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

.footer-heading {
  font-family: var(--font-primary);
  font-size: var(--text-sm);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
  margin-bottom: var(--space-4);
}

.footer-links ul li {
  margin-bottom: var(--space-3);
}

.footer-links a {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  text-decoration: none;
  transition: color var(--transition-fast);
}
.footer-links a:hover { color: var(--color-primary); }

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-2);
  padding-top: var(--space-6);
  border-top: 1px solid var(--color-border);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}