/* ============================================================
   HEADER & NAVIGATION
   Sticky header with CSS-only responsive hamburger menu
   ============================================================ */

.site-header {
  background: #0d1b2a;
  color: #fff;
  padding: 0.75rem 0;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* --- Logo --- */
.logo-link {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-weight: 800;
  font-size: 1.1rem;
  color: #fff;
  text-decoration: none;
}
.logo-link:hover {
  color: #fff;
  text-decoration: none;
}
.logo-link img {
  width: 36px;
  height: 36px;
  border-radius: 0.5rem;
}

/* --- Desktop Nav --- */
.main-nav {
  display: flex;
  gap: 1.5rem;
  align-items: center;
  list-style: none;
  margin: 0;
  padding: 0;
}
.main-nav a {
  color: #fff;
  font-size: 0.9rem;
  font-weight: 500;
  opacity: 0.85;
  text-decoration: none;
  transition: opacity 0.2s ease;
  padding: 0.25rem 0;
}
.main-nav a:hover,
.main-nav a[aria-current="page"] {
  opacity: 1;
  text-decoration: none;
}
.main-nav a[aria-current="page"] {
  font-weight: 700;
  border-bottom: 2px solid #93c5fd;
}

/* --- Hamburger (CSS-only) --- */
.nav-toggle {
  display: none;
}
.nav-toggle-label {
  display: none;
  cursor: pointer;
  padding: 0.5rem;
}
.nav-toggle-label span,
.nav-toggle-label span::before,
.nav-toggle-label span::after {
  display: block;
  width: 24px;
  height: 2px;
  background: #fff;
  border-radius: 2px;
  position: relative;
  transition: all 0.3s ease;
}
.nav-toggle-label span::before,
.nav-toggle-label span::after {
  content: '';
  position: absolute;
  left: 0;
}
.nav-toggle-label span::before { top: -7px; }
.nav-toggle-label span::after { top: 7px; }

/* Hamburger animation */
.nav-toggle:checked + .nav-toggle-label span {
  background: transparent;
}
.nav-toggle:checked + .nav-toggle-label span::before {
  top: 0;
  transform: rotate(45deg);
}
.nav-toggle:checked + .nav-toggle-label span::after {
  top: 0;
  transform: rotate(-45deg);
}

/* --- Mobile --- */
@media (max-width: 768px) {
  .nav-toggle-label {
    display: block;
  }

  .main-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: #0d1b2a;
    flex-direction: column;
    gap: 0;
    padding: 0;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
  }

  .nav-toggle:checked ~ .main-nav {
    max-height: 300px;
  }

  .main-nav a {
    display: block;
    padding: 0.75rem 1.5rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    font-size: 1rem;
  }
  .main-nav a:last-child {
    border-bottom: none;
  }
  .main-nav a:hover {
    background: rgba(255, 255, 255, 0.05);
  }
  .main-nav a[aria-current="page"] {
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    background: rgba(147, 197, 253, 0.1);
  }
}