.project-nav, .project-nav * { box-sizing: border-box; }

.project-nav {
  position: relative;
  z-index: 30;
  width: 100%;
  max-width: 1008px;
  margin: 0 auto;
  padding: 1rem 1.5rem 0;
  display: flex;
  justify-content: flex-end;
}

.project-nav-switcher { position: relative; }
.project-nav-switcher > summary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.65rem;
  min-height: 44px;
  padding: 0.55rem 0.9rem;
  border: 1px solid #d3dfef;
  border-radius: 10px;
  background: #fff;
  color: #334155;
  font: 600 0.9rem/1.4 'Inter', sans-serif;
  list-style: none;
  cursor: pointer;
}
.project-nav-switcher > summary::-webkit-details-marker { display: none; }
.project-nav-switcher > summary::marker { content: ''; }
.project-nav-switcher > summary:hover,
.project-nav-switcher[open] > summary { border-color: #91acd2; background: #f0f5fc; }
.project-nav-arrow { width: 16px; height: 16px; transition: transform 160ms ease; }
.project-nav-switcher[open] .project-nav-arrow { transform: rotate(180deg); }
.project-nav-menu {
  position: absolute;
  top: calc(100% + 0.5rem);
  right: 0;
  width: 220px;
  max-width: calc(100vw - 3rem);
  padding: 0.4rem;
  border: 1px solid #d3dfef;
  border-radius: 12px;
  background: #fff;
  box-shadow: 0 10px 30px rgba(23, 63, 122, 0.12);
}
.project-nav-menu > a {
  display: block;
  padding: 0.7rem 0.85rem;
  border-radius: 7px;
  color: #334155;
  font: 500 0.925rem/1.5 'Inter', sans-serif;
  text-decoration: none;
  white-space: nowrap;
}
.project-nav-menu > a:hover { color: #173f7a; background: #f0f5fc; }
.project-nav-menu > a[aria-current='page'] { color: #173f7a; background: #eaf1fb; font-weight: 700; }
.project-nav-switcher > summary:focus-visible,
.project-nav-menu > a:focus-visible { outline: 2px solid #2563eb; outline-offset: 3px; }

@media (max-width: 480px) {
  .project-nav { padding: 0.75rem 1.1rem 0; }
  .project-nav-menu { max-width: calc(100vw - 2.2rem); }
}
@media (prefers-reduced-motion: reduce) {
  .project-nav-arrow { transition: none; }
}
@media print {
  .project-nav { display: none; }
}