/* ===== Skip Link for Accessibility ===== */
.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--primary-color);
  color: white;
  padding: 8px 16px;
  z-index: 10000;
  transition: top 0.3s;
  text-decoration: none;
  font-weight: 600;
}

.skip-link:focus {
  top: 0;
}

/* ===== Logo Styles ===== */
.logo-img {
  height: 45px;
  width: auto;
}

.hero-logo {
  max-width: 180px;
  height: auto;
  margin-bottom: 1.5rem;
  filter: drop-shadow(0 4px 8px rgba(0,0,0,0.3));
}

/* ===== Section Subtitle ===== */
.section-subtitle {
  color: #666;
  font-size: 1.1rem;
  margin-top: 1rem;
  font-style: italic;
}

/* ===== Hero Slideshow ===== */
.hero {
  position: relative;
  height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 2rem;
  color: white;
  overflow: hidden;
}

.hero-slider {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
}

.hero-slider .slide {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0;
  transition: opacity 1s ease-in-out;
}

.hero-slider .slide.active {
  opacity: 1;
}

.hero::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(rgba(0,0,0,0.5), rgba(0,0,0,0.6));
  z-index: 1;
}

.hero-dots {
  position: absolute;
  bottom: 30px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 12px;
  z-index: 3;
}

.hero-dots .dot {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: rgba(255,255,255,0.5);
  cursor: pointer;
  transition: var(--transition);
  border: 2px solid rgba(255,255,255,0.7);
}

.hero-dots .dot.active,
.hero-dots .dot:hover {
  background: var(--secondary-color);
  border-color: var(--secondary-color);
  transform: scale(1.2);
}

.hero-content {
  position: relative;
  z-index: 2;
  max-width: 800px;
}

/* ===== Hamburger Menu ===== */
.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 5px;
  z-index: 1001;
}

.hamburger span {
  width: 28px;
  height: 3px;
  background: var(--primary-color);
  border-radius: 3px;
  transition: var(--transition);
}

.hamburger.active span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 6px);
}

.hamburger.active span:nth-child(2) {
  opacity: 0;
}

.hamburger.active span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -6px);
}

/* ===== Gallery Section ===== */
.gallery-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}

.gallery-item {
  position: relative;
  border-radius: 12px;
  overflow: hidden;
  box-shadow: var(--shadow);
  aspect-ratio: 4/3;
}

.gallery-item img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}

.gallery-item:hover img {
  transform: scale(1.1);
}

.gallery-overlay {
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  padding: 1.5rem 1rem 1rem;
  background: linear-gradient(transparent, rgba(0,0,0,0.8));
  color: white;
  transform: translateY(100%);
  transition: transform 0.4s ease;
}

.gallery-item:hover .gallery-overlay {
  transform: translateY(0);
}

.gallery-overlay span {
  font-weight: 600;
  font-size: 1.1rem;
}

/* ===== Why Choose Us Section ===== */
.features-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 2rem;
}

.feature-card {
  background: white;
  border-radius: 12px;
  padding: 2rem 1.5rem;
  text-align: center;
  box-shadow: var(--shadow);
  transition: var(--transition);
  border: 1px solid rgba(0,0,0,0.05);
}

.feature-card:hover {
  transform: translateY(-8px);
  box-shadow: 0 12px 30px rgba(0,0,0,0.2);
}

.feature-icon {
  width: 80px;
  height: 80px;
  margin: 0 auto 1.5rem;
  background: linear-gradient(135deg, var(--secondary-color), var(--accent-color));
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  color: white;
  transition: var(--transition);
}

.feature-card:hover .feature-icon {
  transform: scale(1.1) rotate(5deg);
}

.feature-card h3 {
  font-size: 1.1rem;
  margin-bottom: 1rem;
  color: var(--primary-color);
}

.feature-card p {
  color: #666;
  font-size: 0.9rem;
  line-height: 1.7;
}

/* ===== Scroll Reveal Animation ===== */
.reveal {
  opacity: 0;
  transform: translateY(40px);
  transition: opacity 0.8s ease, transform 0.8s ease;
}

.reveal.active {
  opacity: 1;
  transform: translateY(0);
}

/* ===== Footer ===== */
footer {
  background: var(--primary-color);
  color: white;
  border-top: 4px solid var(--secondary-color);
}

.footer-container {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 2rem;
  max-width: 1200px;
  margin: 0 auto;
  padding: 3rem 5% 2rem;
}

.footer-logo {
  height: 60px;
  width: auto;
  margin-bottom: 1rem;
  filter: brightness(0) invert(1);
}

.footer-col h3 {
  font-size: 1.1rem;
  margin-bottom: 1rem;
  color: var(--secondary-color);
}

.footer-col p {
  font-size: 0.9rem;
  line-height: 1.8;
  opacity: 0.9;
}

.footer-col p i {
  margin-right: 8px;
  color: var(--secondary-color);
}

.footer-col a {
  color: white;
  text-decoration: none;
  transition: var(--transition);
}

.footer-col a:hover {
  color: var(--secondary-color);
}

.footer-col ul {
  list-style: none;
}

.footer-col ul li {
  margin-bottom: 0.5rem;
}

.footer-col ul li a {
  color: white;
  text-decoration: none;
  font-size: 0.9rem;
  opacity: 0.9;
  transition: var(--transition);
}

.footer-col ul li a:hover {
  opacity: 1;
  color: var(--secondary-color);
}

.social-links {
  display: flex;
  gap: 12px;
}

.social-links a {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: rgba(255,255,255,0.15);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  text-decoration: none;
  transition: var(--transition);
}

.social-links a:hover {
  background: var(--secondary-color);
  transform: translateY(-3px);
}

.footer-bottom {
  text-align: center;
  padding: 1.5rem 5%;
  border-top: 1px solid rgba(255,255,255,0.2);
  font-size: 0.85rem;
  opacity: 0.8;
}

.footer-bottom p {
  margin-bottom: 0.3rem;
}

.footer-bottom p:last-child {
  margin-bottom: 0;
  font-size: 0.8rem;
  opacity: 0.7;
}

/* ===== Back to Top Button ===== */
.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background: var(--primary-color);
  color: var(--text-light);
  border: none;
  border-radius: 50%;
  width: 50px;
  height: 50px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  cursor: pointer;
  opacity: 0;
  transition: var(--transition);
  z-index: 1000;
  box-shadow: var(--shadow);
}

.back-to-top.show {
  opacity: 1;
}

.back-to-top:hover {
  transform: scale(1.1);
  background: var(--secondary-color);
}

/* ===== Course Card Extended Styles ===== */
.course-code {
  color: #888;
  font-size: 0.85rem;
  margin-bottom: 0.25rem;
}

.course-duration {
  color: var(--accent-color);
  font-weight: 600;
  font-size: 0.9rem;
  margin-bottom: 1rem;
}

.subcourses-container {
  border-top: 1px solid #eee;
  padding-top: 1rem;
  max-height: 300px;
  overflow-y: auto;
}

.subcourse {
  margin-bottom: 1rem;
  background: #f9f9f9;
  border-radius: 8px;
  padding: 0.75rem;
}

.subcourse:last-child {
  margin-bottom: 0;
}

.subcourse-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.5rem;
}

.subcourse-name {
  font-weight: 600;
  color: var(--primary-color);
  font-size: 0.95rem;
}

.subcourse-code {
  color: #888;
  font-size: 0.8rem;
}

.semesters-list {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}

.semester-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.3rem 0.5rem;
  background: white;
  border-radius: 4px;
  font-size: 0.85rem;
}

.semester-name {
  color: #555;
}

.semester-fee {
  color: var(--accent-color);
  font-weight: 600;
}

/* Scrollbar for subcourses */
.subcourses-container::-webkit-scrollbar {
  width: 6px;
}

.subcourses-container::-webkit-scrollbar-track {
  background: #f1f1f1;
  border-radius: 3px;
}

.subcourses-container::-webkit-scrollbar-thumb {
  background: #ccc;
  border-radius: 3px;
}

.subcourses-container::-webkit-scrollbar-thumb:hover {
  background: #aaa;
}

/* ===== Mobile Responsiveness ===== */

/* Tablet: <= 992px */
@media (max-width: 992px) {
  .gallery-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .footer-container {
    grid-template-columns: repeat(2, 1fr);
  }

  .hero h1 {
    font-size: 2.8rem;
  }

  .hero p {
    font-size: 1.1rem;
  }
}

/* Mobile: <= 768px */
@media (max-width: 768px) {
  .hamburger {
    display: flex;
  }

  .nav-links {
    position: fixed;
    top: 0;
    right: -100%;
    width: 70%;
    height: 100vh;
    background: white;
    flex-direction: column;
    padding: 5rem 2rem 2rem;
    box-shadow: -5px 0 20px rgba(0,0,0,0.2);
    transition: right 0.4s ease;
    z-index: 999;
  }

  .nav-links.active {
    right: 0;
  }

  .nav-links a {
    font-size: 1.1rem;
    padding: 0.8rem 0;
    display: block;
    border-bottom: 1px solid #eee;
  }

  .mobile-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.5);
    z-index: 998;
  }

  .mobile-overlay.active {
    display: block;
  }

  .hero h1 {
    font-size: 2.2rem;
  }

  .hero p {
    font-size: 1rem;
  }

  .hero-logo {
    max-width: 140px;
  }

  .section-title h2 {
    font-size: 2rem;
  }

  .courses-grid {
    grid-template-columns: 1fr;
  }

  .features-grid {
    grid-template-columns: 1fr;
  }

  .gallery-grid {
    grid-template-columns: 1fr;
  }

  .footer-container {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .footer-logo {
    margin: 0 auto 1rem;
  }

  .social-links {
    justify-content: center;
  }
}

/* Small Mobile: <= 576px */
@media (max-width: 576px) {
  .hero h1 {
    font-size: 1.8rem;
  }

  .hero p {
    font-size: 0.9rem;
    padding: 0 1rem;
  }

  .btn {
    padding: 10px 24px;
    font-size: 0.9rem;
  }

  section {
    padding: 3rem 4%;
  }

  .section-title h2 {
    font-size: 1.7rem;
  }

  .course-image {
    height: 140px;
    font-size: 2.5rem;
  }

  .course-content {
    padding: 1rem;
  }

  .hero-dots .dot {
    width: 10px;
    height: 10px;
  }
}