body {
  background: linear-gradient(to right, #0a0a0a, #141414);
  color: #ffffff;
  font-family: 'Poppins', sans-serif;
  margin: 0;
  padding: 0;
}

header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px;
  flex-wrap: wrap;
}

.logo {
  display: flex;
  align-items: center;
  gap: 15px;
  text-decoration: none;
  color: white;
}

.logo img {
  width: 40px;
  height: 40px;
  border-radius: 50%;
}

.logo h1 {
  color: #00ffb3;
  font-size: 1.8rem;
  animation: fadeInDown 1s ease-in-out;
}

nav a {
  margin-left: 30px;
  color: #ffffff;
  text-decoration: none;
  font-weight: 600;
  position: relative;
}

nav a::after {
  content: '';
  position: absolute;
  bottom: -5px;
  left: 0;
  width: 0;
  height: 2px;
  background: #00ffb3;
  transition: width 0.3s ease;
}

nav a:hover::after {
  width: 100%;
}

@keyframes fadeInDown {
  from {
    opacity: 0;
    transform: translateY(-20px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.dropdown {
  position: relative;
  display: inline-block;
}


nav a:hover::after,
nav a.active::after {
  content: '';
  width: 100%;
  height: 2px;
  background: #00ffb3;
  position: absolute;
  bottom: -6px;
  left: 0;
  transition: width 0.3s ease;
}

.materials-title {
  text-align: center;
  font-size: 2.2rem;
  color: #00ffb3;
  margin-top: 30px;
}

#searchInput {
  display: block;
  margin: 20px auto;
  padding: 12px 20px;
  border-radius: 30px;
  border: 2px solid #00ffb3;
  background: transparent;
  color: white;
  width: 60%;
  max-width: 500px;
  font-size: 1rem;
}

/* Material Cards */
.materials-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px;
  padding: 30px 20px;
  max-width: 1300px;
  margin: auto;
}

.material-card {
  background: rgba(255, 255, 255, 0.05);
  border: 2px solid #00ffb3;
  border-radius: 20px;
  padding: 25px 20px;
  text-align: center;
  transition: transform 0.3s;
  box-shadow: 0 0 20px rgba(0, 255, 179, 0.05);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: space-between;
}

.material-card:hover {
  transform: translateY(-6px);
  background: rgba(0, 255, 179, 0.1);
}

.material-card i {
  font-size: 2rem;
  margin-bottom: 12px;
  color: #00ffb3;
}

.material-card h3 {
  font-size: 1.2rem;
  margin-bottom: 6px;
}

.material-card p {
  font-size: 0.95rem;
  color: #ccc;
  margin-bottom: 16px;
}

/* Buttons */
.button-group {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
  flex-wrap: nowrap;
  border-top: 1px solid rgba(255, 255, 255, 0.2);
  padding-top: 12px;
  margin-top: 16px;
}


.btn {
  padding: 10px 18px;
  border-radius: 25px;
  border: none;
  font-weight: 600;
  font-size: 0.95rem;
  color: #fff;
  cursor: pointer;
  transition: 0.3s ease;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  position: relative;
  background-size: 300%;
  background-position: left;
  overflow: hidden;
}

.btn i {
  position: relative;
  z-index: 2;
}

.btn::before {
  content: "";
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(circle, rgba(255, 255, 255, 0.15), transparent 70%);
  z-index: 1;
  transform: scale(0);
  transition: transform 0.4s ease;
}

.btn:hover::before {
  transform: scale(1);
}

.theory-btn {
  background: #092c2d;
  border: 1px solid #00e6e6;
  box-shadow: 0 0 10px #00ffe7, 0 0 20px rgba(0, 255, 255, 0.2);
}

.theory-btn:hover {
  background-color: #014848;
  color: #00fff7;
}

.practical-btn {
  background: #2c0d26;
  border: 1px solid #ff0080;
  box-shadow: 0 0 10px #ff1aa6, 0 0 20px rgba(255, 0, 128, 0.2);
}

.practical-btn:hover {
  background-color: #4d0b3e;
  color: #ffb6e6;
}

/* Modal */
.pdf-modal {
  display: none;
  position: fixed;
  z-index: 9999;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(5, 5, 5, 0.95);
  justify-content: center;
  align-items: center;
  touch-action: manipulation;
}

.modal-content {
  width: 90%;
  height: 90%;
  position: relative;
  background: #0d0d0d;
  border: 2px solid #00ffb3;
  border-radius: 12px;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

.modal-content iframe {
  flex-grow: 1;
  width: 100%;
  height: 100%;
  border: none;
  touch-action: pan-x pan-y;
}

.close {
  position: absolute;
  top: 10px;
  right: 20px;
  font-size: 2rem;
  color: #00ffb3;
  cursor: pointer;
  z-index: 1000;
}

/*FOOTER*/
footer {
  text-align: center;
  padding: 20px;
  background: linear-gradient(to right, black, #00ffb3, black);
  ;
  backdrop-filter: blur(10px);
  margin-top: 40px;
  font-size: 0.9rem;
}

.footer-container {
  background-color: #0e0e0e;
  padding: 20px;
  text-align: center;
  color: black;
  position: relative;
}

.footer-container p {
  margin-bottom: 10px;
  font-size: 14px;
}

.credit-buttons {
  display: flex;
  justify-content: center;
  gap: 20px;
  flex-wrap: wrap;
}

.credit-btn {
  position: relative;
  padding: 10px 20px;
  border: 2px solid white;
  border-radius: 30px;
  background: transparent;
  color: black;
  font-weight: bold;
  cursor: pointer;
  transition: all 0.3s ease;
}

.credit-btn:hover {
  background-color: #00ffb3;
  color: black;
}

.popup-card {
  display: none;
  position: absolute;
  bottom: 45px;
  left: 50%;
  transform: translateX(-50%);
  background-color: #1a1a1a;
  color: white;
  padding: 15px;
  border-radius: 10px;
  box-shadow: 0 0 10px rgba(0, 255, 179, 0.4);
  width: 250px;
  z-index: 100;
  text-align: left;
}

.credit-btn:hover .popup-card {
  display: block;
}

.popup-card .social-links {
  display: flex;
  gap: 12px;
  margin: 6px 0;
}

.popup-card .social-links a {
  color: #00ffb3;
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 4px;
}

.popup-card .social-links a:hover {
  text-decoration: underline;
}

.popup-card i {
  margin-right: 6px;
}

.popup-card hr {
  border-color: #00ffb3;
  margin: 10px 0;
}

@media (max-width: 600px) {
  .popup-card {
    width: 220px;
    font-size: 14px;
  }

  .credit-btn {
    padding: 8px 14px;
    font-size: 14px;
  }

  .credit-buttons {
    flex-direction: column;
    align-items: center;
  }
}