/* Glassmorphism chung */
.submenu, .mobile-sidebar {
  background: rgba(255, 255, 255, 0.2);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid rgba(255, 255, 255, 0.3);
  border-radius: 16px;
}

/* Dropdown desktop */
.submenu {
  position: absolute;
  top: 100%;
  left: 0;
  min-width: 220px;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: all 0.3s ease;
  padding: 0.75rem 0;
  z-index: 40;
}
.group:hover .submenu {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}
.submenu li a {
  display: block;
  padding: 0.5rem 1rem;
  color: #374151;
  transition: 0.25s;
}
.submenu li a:hover {
  background: rgba(255,255,255,0.4);
  color: #2563eb;
}

/* CTA Button */
.cta {
  background: linear-gradient(135deg, #3b82f6, #2563eb);
  color: #fff !important;
  font-weight: 600;
  padding: 0.5rem 1rem;
  border-radius: 9999px;
  transition: 0.3s;
}
.cta:hover {
  background: linear-gradient(135deg, #2563eb, #1d4ed8);
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(37, 99, 235, 0.25);
}

/* Overlay */
.overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.4);
  backdrop-filter: blur(4px);
  opacity: 0;
  pointer-events: none;
  transition: 0.3s ease;
  z-index: 40;
}
.overlay.active {
  opacity: 1;
  pointer-events: auto;
}

/* Mobile Sidebar */
.mobile-sidebar {
  position: fixed;
  top: 0;
  right: -100%;
  width: 80%;
  max-width: 320px;
  height: 100%;
  transition: right 0.3s ease;
  z-index: 50;
  padding: 1rem;
}
.mobile-sidebar.active {
  right: 0;
}

/* Mobile menu links */
.mobile-sidebar a {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  transition: 0.25s;
}
.mobile-sidebar a:hover {
  color: #2563eb;
}

/* responsive */

/* Responsive chung cho body */
body {
  font-family: system-ui, sans-serif;
  line-height: 1.6;
  word-wrap: break-word;
  overflow-x: hidden;
}

/* Hero Section */
.hero-bg {
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding-top: 5rem; /* tránh header */
}

/* Form trên mobile */
form input, form button {
  width: 100%;
}

/* Sidebar trên mobile */
#mobile-menu {
  width: 80%;
  max-width: 320px;
}

/* Grid bài viết - mobile stack, tablet 2 cột, desktop 3 cột */
.grid-posts {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}
@media (min-width: 640px) {
  .grid-posts {
    grid-template-columns: repeat(2, 1fr);
  }
}
@media (min-width: 1024px) {
  .grid-posts {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* Responsive cho hình ảnh */
img {
  max-width: 100%;
  height: auto;
  display: block;
}

/* Footer responsive */
footer .grid {
  grid-template-columns: 1fr;
}
@media (min-width: 768px) {
  footer .grid {
    grid-template-columns: repeat(2, 1fr);
  }
}
@media (min-width: 1024px) {
  footer .grid {
    grid-template-columns: repeat(4, 1fr);
  }
}

/* Cookie banner stack trên mobile */
#cookie-banner .flex {
  flex-direction: column;
  text-align: center;
}
@media (min-width: 640px) {
  #cookie-banner .flex {
    flex-direction: row;
    text-align: left;
  }
}