.header-principal {
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(94, 167, 230, 0.15);
  position: sticky;
  top: 0;
  z-index: 1000;
  padding: 12px 0;
}

.header-contenu {
  width: min(1100px, calc(100% - 40px));
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: #10263d;
  font-weight: 900;
  font-size: 1.1rem;
}

.logo img {
  height: 40px;
  width: auto;
}

.navigation {
  display: flex;
  gap: 24px;
}

.navigation a {
  text-decoration: none;
  color: rgba(16, 38, 61, 0.7);
  font-size: 0.95rem;
  font-weight: 600;
  transition: color 0.2s;
}

.navigation a:hover {
  color: #5ea7e6;
}

.navigation a.active {
  color: #5ea7e6;
  position: relative;
}

.navigation a.active::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 100%;
  height: 2px;
  background: #5ea7e6;
  border-radius: 2px;
}

@media (max-width: 768px) {
  .header-contenu {
    flex-direction: column;
    gap: 16px;
  }
  
  .navigation {
    gap: 12px;
    flex-wrap: wrap;
    justify-content: center;
  }
  
  .navigation a {
    font-size: 0.85rem;
  }
}