/* Desktop post nav: horizontal layout, visible above 768px */
.post-nav-desktop {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 2rem 0;
  margin-top: 3rem;
}

/* Mobile post nav: hidden above 768px */
.post-nav-mobile {
  display: none;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
  padding: 1.5rem 0;
  margin-top: 2rem;
}

.post-nav-mobile-row {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1rem;
  width: 100%;
}

@media (max-width: 768px) {
  .post-nav-desktop {
    display: none;
  }

  .post-nav-mobile {
    display: flex;
  }
}

.post-nav-link {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  text-decoration: none;
  color: inherit;
  opacity: 0.8;
  transition: opacity 0.2s;
}

.post-nav-link:hover {
  opacity: 1;
}

.post-nav-next {
  justify-content: flex-end;
}

/* Back to top button */
.post-nav-top {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 2.5rem;
  height: 2.5rem;
  border-radius: 50%;
  border: 1px solid var(--pico-muted-border-color);
  text-decoration: none;
  color: inherit;
  flex-shrink: 0;
  transition:
    opacity 0.2s,
    background-color 0.2s;
  opacity: 0.8;
}

/* Light mode: darker background for contrast */
:root:not([data-theme="dark"]) .post-nav-top {
  background-color: #d1d5db;
}

/* Dark mode: lighter background for contrast */
[data-theme="dark"] .post-nav-top {
  background-color: #374151;
}

.post-nav-top:hover {
  opacity: 1;
}