/* Paper Tiger — header CSS. Requires tokens.css. */

.pt-container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding-left: var(--container-gutter);
  padding-right: var(--container-gutter);
}

.pt-skiplink {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--color-neutral-100);
  color: var(--color-white);
  padding: 0.5rem 1rem;
  z-index: 1000;
  transition: top 0.2s ease;
}
.pt-skiplink:focus { left: 0; }

/* Princeton bar */
.pt-princeton-bar {
  background: var(--color-neutral-100);
  border-bottom: 1px solid var(--color-neutral-90);
}
.pt-princeton-bar .pt-container {
  padding-top: 1rem;
  padding-bottom: 1rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.pt-pu-logo img { width: 220px; height: auto; display: block; filter: brightness(0) invert(1); }
@media (min-width: 48rem) {
  .pt-pu-logo img { width: 260px; }
}

/* Site identity */
.pt-site-branding {
  background: var(--color-white);
  padding: var(--space-8) 0;
  border-bottom: 1px solid var(--color-neutral-10);
}
.pt-site-branding__row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-6);
}
.pt-site-logo-group {
  display: flex;
  align-items: center;
  gap: var(--space-6);
}
.pt-site-logo img { max-height: 72px; width: auto; }
.pt-site-info { flex: 1 1 auto; }
.pt-site-name {
  margin: 0;
  font-family: var(--font-display);
  font-weight: var(--font-weight-bold);
  font-size: 1.5rem;
  line-height: 1.1;
  letter-spacing: -0.02em;
}
.pt-site-name a { color: var(--color-neutral-100); text-decoration: none; }
.pt-site-slogan {
  margin: 0.25rem 0 0;
  color: var(--color-neutral-60);
  font-size: var(--font-size-sm);
  font-family: "Libre Franklin", sans-serif;
  width: 23rem;
  max-width: 100%;
  text-align: center;
}
@media (min-width: 48rem) {
  .pt-site-name { font-size: 2.5rem; }
}

.pt-seas-lockup {
  display: none;
}
@media (min-width: 62rem) {
  .pt-seas-lockup {
    display: block;
    max-width: 280px;
  }
  .pt-seas-lockup img { width: 100%; height: auto; }
}

/* Nav */
.pt-main-menu {
  background: rgba(18, 18, 18, 0.95);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  color: var(--color-white);
  position: sticky;
  top: 0;
  z-index: 100;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
  box-shadow: 0 4px 30px rgba(0, 0, 0, 0.1);
}
.pt-main-menu .pt-container {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
}

.pt-nav-toggle {
  background: transparent;
  color: var(--color-white);
  border: 0;
  padding: 1rem 0.5rem;
  font-family: var(--font-label);
  font-weight: var(--font-weight-bold);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: var(--space-2);
  margin-left: auto;
}
@media (min-width: 62rem) {
  .pt-nav-toggle { 
    display: none; 
    margin-left: 0;
  }
}

.pt-nav-collapse {
  display: none;
  width: 100%;
}
@media (min-width: 62rem) {
  .pt-nav-collapse { 
    display: flex; 
    justify-content: space-between; 
    align-items: center;
  }
}

.pt-nav {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
}
@media (min-width: 62rem) {
  .pt-nav { flex-direction: row; }
}

.pt-nav a {
  color: var(--color-white);
  text-decoration: none;
  display: block;
  padding: 1rem 1.25rem;
  font-family: "Libre Franklin", sans-serif;
  font-weight: 700;
  transition: all 0.2s ease;
  position: relative;
  border-bottom: 6px solid transparent;
}

@media (min-width: 62rem) {
  .pt-nav--utility {
    margin-left: auto;
  }
}

@media (max-width: 61.99rem) {
  .pt-nav--utility {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    margin-top: 0.5rem;
    padding-top: 0.5rem;
  }
}

.pt-nav a:hover,
.pt-nav a:focus {
  color: #f58025;
  border-bottom-color: #f58025;
}
.pt-nav a.is-active {
  border-bottom-color: #f58025;
}

.pt-nav__item { position: relative; }
.pt-submenu {
  list-style: none;
  margin: 0;
  padding: 0.5rem 0;
  background: rgba(29, 29, 29, 0.98);
  backdrop-filter: blur(15px);
  -webkit-backdrop-filter: blur(15px);
  border-top: 3px solid var(--color-brand-70);
}
@media (min-width: 62rem) {
  .pt-submenu {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    min-width: 18rem;
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
  }
  .pt-nav__item:hover .pt-submenu,
  .pt-nav__item:focus-within .pt-submenu {
    display: block;
    animation: pt-fade-in 0.2s ease;
  }
}

@keyframes pt-fade-in {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

.pt-submenu a {
  padding: 0.75rem 1.5rem;
  font-weight: var(--font-weight-regular);
  font-size: var(--font-size-sm);
}
.pt-submenu a:hover {
  background: var(--color-neutral-100);
}

/* Search Flyout */
.pt-search-bar {
  background: var(--color-neutral-100);
  border-top: 1px solid var(--color-neutral-90);
  overflow: hidden;
  max-height: 0;
  transition: max-height 0.3s ease-out;
}
.pt-search-bar.is-open {
  max-height: 100px;
}
.pt-search-bar .pt-container {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  padding-top: var(--space-4);
  padding-bottom: var(--space-4);
}
.pt-search-form {
  display: flex;
  flex: 1;
  gap: var(--space-2);
}
.pt-search-form input[type="search"] {
  flex: 1;
  padding: 0.75rem 1rem;
  font: inherit;
  border: 1px solid var(--color-neutral-60);
  background: var(--color-white);
  color: var(--color-neutral-100);
  border-radius: var(--radius-none);
}

.sr-only {
  position: absolute !important;
  width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0;
}