/* Cosmic Sci-Fi Theme for Interstella */

body {
  font-family: 'Roboto', sans-serif;
  background: linear-gradient(to bottom, #000428, #004e92);
  color: #ffffff;
  margin: 0;
  padding: 0;
  position: relative;
  overflow-x: hidden;
}

/* Starry Background Animation */
body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-image: 
    radial-gradient(2px 2px at 20px 30px, #eee, transparent),
    radial-gradient(2px 2px at 40px 70px, rgba(255,255,255,0.8), transparent),
    radial-gradient(1px 1px at 90px 40px, #fff, transparent),
    radial-gradient(1px 1px at 130px 80px, rgba(255,255,255,0.6), transparent),
    radial-gradient(2px 2px at 160px 30px, #ddd, transparent);
  background-repeat: repeat;
  background-size: 200px 100px;
  animation: stars 50s linear infinite;
  z-index: -1;
  opacity: 0.5;
}

@keyframes stars {
  from { transform: translateY(0px); }
  to { transform: translateY(-100px); }
}

/* Headers with Orbitron */
h1, h2, h3, h4, h5, h6 {
  font-family: 'Orbitron', monospace;
  color: #00d4ff;
  text-shadow: 0 0 10px rgba(0, 212, 255, 0.5);
}

/* Fade-in Animation for Sections */
section {
  animation: fadeIn 1s ease-in-out;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Navbar Enhancements */
.navbar {
  background: linear-gradient(to bottom, #000428, #004e92) !important;
  border-bottom: 2px solid #00d4ff;
  box-shadow: 0 4px 8px rgba(0, 212, 255, 0.3);
}

.navbar-brand img {
  filter: drop-shadow(0 0 5px #00d4ff);
}

.nav-link {
  color: #ffffff !important;
  transition: color 0.3s;
}

.nav-link:hover {
  color: #00d4ff !important;
  text-shadow: 0 0 5px #00d4ff;
}

/* Cards with Glow */
.card {
  background: rgba(0, 0, 0, 0.7);
  border: 1px solid #00d4ff;
  box-shadow: 0 0 15px rgba(0, 212, 255, 0.2);
  transition: box-shadow 0.3s;
}

.card:hover {
  box-shadow: 0 0 25px rgba(0, 212, 255, 0.5);
}

/* Buttons */
.btn-primary {
  background: linear-gradient(45deg, #00d4ff, #004e92);
  border: none;
  box-shadow: 0 0 10px rgba(0, 212, 255, 0.3);
  transition: all 0.3s;
}

.btn-primary:hover {
  box-shadow: 0 0 20px rgba(0, 212, 255, 0.6);
  transform: translateY(-2px);
}

/* Footer */
footer {
  background: linear-gradient(to top, #000428, #004e92);
  border-top: 2px solid #00d4ff;
}

/* Math Equations */
.mathjax {
  text-align: center;
  margin: 20px 0;
}

/* Responsive */
@media (max-width: 768px) {
  body::before {
    background-size: 100px 50px;
  }
  .navbar-brand {
    width: 120px;
  }
  .navbar-brand img {
    height: 30px;
  }
}