header { 
  opacity: 0;
  pointer-events: none;
  position: fixed;
  top: 0;
  width: 100%;
  background: var(--color-bg);
  box-shadow: 0 2px 4px rgba(0,0,0,0.2);
  transition: opacity 0.3s ease;
  z-index: 1000;
}

.header-icons {
  display: flex;
  align-items: center;
}

.header-icons > *:not(:first-child) { margin-left: 1rem; }

.always-visible {
  opacity: 1;
  pointer-events: auto;
}

#theme-toggle, #language-toggle button { 
  background: none; 
  border: none;
  padding: 0;
  cursor: pointer;
  transition: opacity var(--transition-duration);
}

#theme-toggle img,
#language-toggle img {
  width: 24px;
  height: 24px;
  display: block;
  object-fit: contain;
  margin-right: 30px;
}

#language-toggle {
  display: flex;
  align-items: center;
  margin-left: 1rem;
}

nav .container { 
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 0;
}

#nav-logo {
  width: 350px;
  max-width: 100%;
  height: auto;
}

/* Navigation logo: smaller on mobile */
@media (max-width: 600px) {
  #nav-logo {
    margin-top: 5px;
    min-width: 120px;
    max-width: 180px;
    margin-left: 10px;
  }
}