/* ===== Botão voltar ao topo ===== */
.btn-topo {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  z-index: 90;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  border: none;
  background: var(--accent);
  color: #fff;
  font-size: 1.1rem;
  cursor: pointer;
  box-shadow: var(--shadow-md);
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px);
  transition: opacity 0.3s ease, transform 0.3s ease, background 0.2s ease;
}

.btn-topo.visivel {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.btn-topo:hover {
  background: var(--accent-soft);
  transform: translateY(-3px);
}

/* ===== Lightbox ===== */
.lightbox {
  position: fixed;
  inset: 0;
  z-index: 200;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 2rem;
  background: rgba(0, 0, 0, 0.9);
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s ease;
}

.lightbox.aberto {
  opacity: 1;
  visibility: visible;
}

.lightbox img {
  max-width: 90vw;
  max-height: 85vh;
  border-radius: 10px;
  box-shadow: var(--shadow-md);
}

.lightbox-fechar {
  position: absolute;
  top: 1.5rem;
  right: 2rem;
  background: transparent;
  border: none;
  color: #fff;
  font-size: 2.5rem;
  line-height: 1;
  cursor: pointer;
  transition: color 0.2s ease;
}

.lightbox-fechar:hover {
  color: var(--accent-soft);
}

/* Sinaliza que imagens de projeto são clicáveis */
.conteudo-projeto img,
.carrossel-imagens .slide {
  cursor: zoom-in;
}