/* --- HERO SECTION --- */
.congres-hero {
  position: relative;
  color: white;
  text-align: center;
  padding: 120px 5%;
  overflow: hidden;
  min-height: 50vh;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* Image floutée en arrière-plan */
.congres-hero::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: url("../congres2025pic/header.png") center/cover no-repeat;
  filter: blur(4px);
  transform: scale(1.1);
  z-index: 1;
}

/* Overlay gradient moderne */
.congres-hero::after {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(
    135deg,
    rgba(0, 119, 182, 0.5) 0%,
    rgba(8, 175, 209, 0.5) 100%
  );
  z-index: 2;
}

/* Contenu du hero */
.congres-hero-content {
  position: relative;
  z-index: 3;
  max-width: 900px;
  animation: fadeInUp 0.8s ease-out;
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.congres-hero-content h1 {
  font-size: clamp(2rem, 5vw, 3.5rem);
  margin-bottom: 20px;
  font-weight: 700;
  text-shadow: 0 4px 15px rgba(0, 0, 0, 0.3);
  line-height: 1.2;
}

.congres-hero-content p {
  font-size: clamp(1.1rem, 2vw, 1.4rem);
  opacity: 0.95;
  font-weight: 300;
  text-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
}

/* --- INTRO SECTION --- */
.congres-intro {
  max-width: 1100px;
  margin: 0 auto;
  padding: 80px 20px;
  text-align: center;
}

.congres-intro h2 {
  font-size: 2.2rem;
  margin-bottom: 25px;
  color: #0077b6;
  font-weight: 700;
  position: relative;
  padding-bottom: 20px;
}

.congres-intro h2::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 80px;
  height: 4px;
  background: linear-gradient(90deg, #0077b6, #08afd1);
  border-radius: 2px;
}

.congres-intro p {
  color: #495057;
  font-size: 1.1rem;
  line-height: 1.8;
  max-width: 900px;
  margin: 0 auto;
}

/* --- GALLERY SECTION --- */
.gallery {
  max-width: 1200px;
  margin: 0 auto;
  padding: 80px 20px;
  background: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 100%);
}

.gallery h2 {
  margin-bottom: 50px;
  font-size: 2.2rem;
  color: #0077b6;
  font-weight: 700;
  text-align: center;
  position: relative;
  padding-bottom: 20px;
}

.gallery h2::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 80px;
  height: 4px;
  background: linear-gradient(90deg, #0077b6, #08afd1);
  border-radius: 2px;
}

.gallery-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 20px;
}

.gallery-grid img {
  width: 100%;
  height: 280px;
  object-fit: cover;
  border-radius: 12px;
  box-shadow: 0 8px 25px rgba(0, 119, 182, 0.12);
  transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
  cursor: pointer;
  position: relative;
  overflow: hidden;
}

.gallery-grid img::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(
    135deg,
    rgba(0, 119, 182, 0.3) 0%,
    transparent 60%
  );
  opacity: 0;
  transition: opacity 0.4s ease;
}

.gallery-grid img:hover {
  transform: translateY(-10px) scale(1.03);
  box-shadow: 0 20px 45px rgba(0, 119, 182, 0.25);
}

.gallery-grid img:hover::before {
  opacity: 1;
}

/* --- LIGHTBOX --- */
.lightbox {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.95);
  justify-content: center;
  align-items: center;
  z-index: 2000;
  overflow: hidden;
  backdrop-filter: blur(10px);
  animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

.lightbox.open {
  display: flex;
}

.lightbox-img {
  max-width: 90%;
  max-height: 85%;
  border-radius: 8px;
  box-shadow: 0 25px 80px rgba(0, 0, 0, 0.8);
  animation: zoomIn 0.3s ease;
}

@keyframes zoomIn {
  from {
    opacity: 0;
    transform: scale(0.8);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

.lightbox-close,
.lightbox-prev,
.lightbox-next {
  position: absolute;
  color: white;
  font-size: 2.5rem;
  cursor: pointer;
  user-select: none;
  transition: all 0.3s ease;
  background: rgba(255, 255, 255, 0.1);
  width: 50px;
  height: 50px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  backdrop-filter: blur(5px);
}

.lightbox-close {
  top: 30px;
  right: 30px;
  font-weight: 300;
}

.lightbox-close:hover {
  background: rgba(220, 53, 69, 0.8);
  transform: rotate(90deg);
}

.lightbox-prev {
  left: 30px;
  top: 50%;
  transform: translateY(-50%);
}

.lightbox-next {
  right: 30px;
  top: 50%;
  transform: translateY(-50%);
}

.lightbox-prev:hover,
.lightbox-next:hover {
  background: rgba(0, 119, 182, 0.8);
  transform: translateY(-50%) scale(1.1);
}

.lightbox-next:hover {
  transform: translateY(-50%) scale(1.1);
}

/* --- CONCLUSION SECTION --- */
.conclusion {
  max-width: 1100px;
  margin: 0 auto;
  padding: 80px 20px;
  text-align: center;
  background: white;
}

.conclusion h2 {
  font-size: 2rem;
  margin-bottom: 25px;
  color: #0077b6;
  font-weight: 700;
  position: relative;
  padding-bottom: 20px;
}

.conclusion h2::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 80px;
  height: 4px;
  background: linear-gradient(90deg, #0077b6, #08afd1);
  border-radius: 2px;
}

.conclusion p {
  color: #495057;
  font-size: 1.1rem;
  line-height: 1.8;
  max-width: 800px;
  margin: 0 auto;
}

/* ==========================================
   RESPONSIVE DESIGN
   ========================================== */

@media (max-width: 992px) {
  .congres-hero {
    padding: 100px 5%;
    min-height: 50vh;
  }

  .gallery-grid {
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 16px;
  }

  .gallery-grid img {
    height: 240px;
  }
}

@media (max-width: 768px) {
  .congres-hero {
    padding: 80px 5%;
    min-height: 40vh;
  }

  .congres-intro,
  .gallery,
  .conclusion {
    padding: 60px 20px;
  }

  .congres-intro h2,
  .gallery h2,
  .conclusion h2 {
    font-size: 1.8rem;
  }

  .gallery-grid {
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 12px;
  }

  .gallery-grid img {
    height: 220px;
  }

  .lightbox-close {
    top: 15px;
    right: 15px;
    font-size: 2rem;
    width: 40px;
    height: 40px;
  }

  .lightbox-prev,
  .lightbox-next {
    font-size: 2rem;
    width: 40px;
    height: 40px;
  }

  .lightbox-prev {
    left: 15px;
  }

  .lightbox-next {
    right: 15px;
  }
}

@media (max-width: 520px) {
  .congres-hero {
    padding: 60px 20px;
  }

  .congres-intro,
  .gallery,
  .conclusion {
    padding: 50px 15px;
  }

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

  .gallery-grid img {
    height: 250px;
  }

  .lightbox-img {
    max-width: 95%;
    max-height: 80%;
  }
}
/* ==========================================
   SPONSORS SECTION
   ========================================== */

.sponsors-section {
  padding: 100px 8%;
  background: var(--bg-gradient);
}

.sponsors-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 40px;
  max-width: 1200px;
  margin: 0 auto;
  align-items: center;
}

.sponsor-card {
  background: white;
  padding: 30px;
  border-radius: 16px;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  display: flex;
  align-items: center;
  justify-content: center;
  height: 140px;
}

.sponsor-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-md);
}

.sponsor-card img {
  max-width: 100%;
  max-height: 80px;
  object-fit: contain;
  filter: grayscale(100%);
  opacity: 0.7;
  transition: var(--transition);
}

.sponsor-card:hover img {
  filter: grayscale(0%);
  opacity: 1;
}