/* Global Gradient Neon Theme */
body {
  margin: 0;
  font-family: 'Poppins', sans-serif;
  background: linear-gradient(120deg, #5ea6fd, #7c4bdd, #e27ab9);
  background-size: 400% 400%;
  animation: gradientBG 15s ease infinite;
  color: #fefafa;
  transition: background 0.5s, color 0.5s;
}

/* Hide sections by default; show only the active one */
section {
  display: none;
  padding: 20px;
}
section.active {
  display: block;
}

/* Background video with parallax effect */
body::before {
  content: "";
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: -2;
  transform: translateZ(-1px) scale(2);
  filter: brightness(0.5) blur(1px);
}

/* Gradient animation */
@keyframes gradientBG {
  10% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

/* Glassmorphism cards, forms, navbar */
.card, .form-control, .form-select, .navbar, .btn-outline-light, .tab-content {
  background: rgba(255, 255, 255, 0.05);
  backdrop-filter: blur(10px) saturate(180%);
  border-radius: 1rem;
  border: 1px solid rgba(255,255,255,0.2);
  transition: all 0.3s ease;
  color: #fff;
}

/* Hover effects for neon */
.card:hover, .btn:hover, .nav-link:hover {
  box-shadow: 0 0 20px rgba(253, 134, 253, 0.6), 0 0 30px rgba(0, 255, 255, 0.6);
  transform: translateY(-2px);
}

/* Navbar styling */
.navbar {
  background: rgba(0,0,0,0.3) !important;
  box-shadow: 0 0 15px rgba(71, 9, 142, 0.83);
}

/* Tabs */
.nav-tabs .nav-link.active {
  background: rgba(4, 115, 242, 0.61);
  border-color: rgba(255,255,255,0.2);
  color: #ff6ec4;
}

/* Dark mode overrides */
body.dark {
  background: linear-gradient(120deg, #2a0d3e, #0d0d30, #330029);
  color: #e0e0e0;
}
body.dark .card, body.dark .form-control, body.dark .form-select, body.dark .navbar, body.dark .tab-content {
  background: rgba(115, 180, 255, 0.495);
  border-color: rgb(34, 255, 240);
  color: #ffffff;
}
body.dark .nav-tabs .nav-link.active {
  color: #fd94c9;
}

/* Buttons */
.btn-outline-light {
  color: #fff;
  border-color: #fff;
}
.btn-outline-light:hover {
  background: rgba(255, 255, 255, 0.2);
  color: #fff;
}

/* Flashcard styling */
  #flashcard {
    perspective: 1000px;
}
#flashcard .card {
  transition: transform 0.6s;
  transform-style: preserve-3d;
  background: rgba(255,255,255,0.05);
  border: 1px solid rgba(255,255,255,0.2);
}

/* Neon colors and effect for footer */
footer a:hover {
  color: #ff6ec4;
  text-shadow: 0 0 5px #eeff6e, 0 0 10px #d254a0, 0 0 20px #d36eff, 0 0 40px #6532de;
  transform: scale(1.5);
  transition: all 0.5s;
}

/* Sticky Footer */
html, body {
  height: 100%;
}
body {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}
main {
  flex: 1;
}

/* Responsive tweaks */
@media (max-width: 768px) {
  .card, .form-control, .form-select {
    font-size: 0.9rem;
  }
}