/**
 * Header + shell do placeholder — carregar no <head> de todas as páginas.
 */
#header-placeholder {
  position: sticky;
  top: 0;
  z-index: 100;
  width: 100%;
  min-height: 88px;
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  background: rgba(10, 25, 47, 0.97);
  border-bottom: 1px solid rgba(12, 68, 102, 0.4);
  contain: layout style;
}

#header-placeholder .site-header {
  position: relative;
  top: auto;
  border-bottom: none;
  margin: 0;
}

.site-header {
  position: relative;
  z-index: 1;
  width: 100%;
  padding: 0 5%;
  height: 88px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: rgba(10, 25, 47, 0.97);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid rgba(12, 68, 102, 0.4);
}

.site-header::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 1px;
  background: linear-gradient(
    90deg,
    transparent 0%,
    rgba(12, 68, 102, 0.8) 30%,
    rgba(30, 144, 255, 0.6) 60%,
    transparent 100%
  );
}

.header-logo {
  height: 68px;
  width: auto;
  filter: brightness(1.1) drop-shadow(0 0 8px rgba(30, 144, 255, 0.2));
  transition: filter 0.3s ease, transform 0.3s ease, opacity 0.5s ease;
  flex-shrink: 0;
  cursor: pointer;
  opacity: 0;
}

.header-logo.loaded {
  opacity: 1;
}

.header-logo:hover {
  filter: brightness(1.35) drop-shadow(0 0 18px rgba(30, 144, 255, 0.55));
  transform: scale(1.04);
}

.header-nav {
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  align-items: center;
  gap: 2px;
  background: rgba(12, 68, 102, 0.15);
  border: 1px solid rgba(30, 144, 255, 0.15);
  border-radius: 12px;
  padding: 6px 8px;
}

.nav-link {
  position: relative;
  font-size: 0.74rem;
  font-weight: 700;
  letter-spacing: 1px;
  text-transform: uppercase;
  text-decoration: none;
  color: rgba(255, 255, 255, 0.5);
  padding: 8px 20px;
  border-radius: 8px;
  transition: color 0.25s ease, background 0.25s ease;
  white-space: nowrap;
  cursor: pointer;
}

.nav-link:hover {
  color: rgba(255, 255, 255, 0.95);
  background: rgba(30, 144, 255, 0.12);
}

.nav-link.active {
  color: #fff;
  background: rgba(30, 144, 255, 0.18);
}

@media (max-width: 900px) {
  .header-nav {
    position: static;
    transform: none;
  }

  .site-header {
    gap: 16px;
    justify-content: space-between;
  }
}

@media (max-width: 600px) {
  .nav-link {
    font-size: 0.62rem;
    padding: 6px 10px;
  }

  #header-placeholder {
    min-height: 72px;
  }

  .site-header {
    height: 72px;
  }
}