/*
 * Header — spec-sheet titlebar.
 * IMPORTANT: All selectors are scoped to `header:not(.section-header)` so they only affect
 * the site titlebar — NOT the <header class="section-header"> elements
 * nested inside each <section>. A bare `header { … }` selector would leak
 * height/sticky/border-bottom into every section header and break layout.
 */

header:not(.section-header) {
  width: 100%;
  background: var(--paper);
  border-bottom: 1px solid var(--ink);
  position: sticky;
  top: 0;
  z-index: var(--z-index-header);
  height: var(--header-height);
  /* Needed so the mobile dropdown positions relative to the header bar */
  overflow: visible;
}
.dark-theme header:not(.section-header) { background: var(--paper); border-bottom-color: var(--ink); }

.header-content {
  display: grid;
  grid-template-columns: auto auto 1fr auto;
  align-items: center;
  gap: var(--s-5);
  height: var(--header-height);
  font-family: var(--font-mono);
  font-size: var(--t-12);
}

.logo { display: flex; align-items: center; gap: var(--s-3); }
.logo .logo-mark {
  font-family: var(--font-mono);
  font-size: var(--t-12);
  font-weight: 700;
  letter-spacing: 0.06em;
  padding: 3px 6px;
  background: var(--ink);
  color: var(--paper);
  border: 1px solid var(--ink);
}
.logo .logo-meta {
  color: var(--ink-2);
  font-size: var(--t-11);
  letter-spacing: 0.10em;
  text-transform: uppercase;
}
.logo h1 {
  font-size: var(--t-12);
  font-weight: 500;
  letter-spacing: 0.06em;
  margin: 0;
  color: var(--ink);
  text-transform: uppercase;
}

header:not(.section-header) nav { justify-self: end; }
header:not(.section-header) nav ul {
  display: flex; list-style: none; gap: var(--s-5); margin: 0; padding: 0;
}
header:not(.section-header) nav ul li a {
  font-family: var(--font-mono);
  font-size: var(--t-11);
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-2);
  text-decoration: none;
  padding: 4px 0;
  position: relative;
  transition: color var(--dur-1) var(--ease-step);
}
header:not(.section-header) nav ul li a:hover { color: var(--ink); }
/* Hover indicator — single red tick above the link, not a sliding underline. */
header:not(.section-header) nav ul li a::after {
  content: '';
  position: absolute;
  top: -2px; left: 0; right: 0;
  height: 2px;
  background: var(--mark);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--dur-2) var(--ease-snap);
}
header:not(.section-header) nav ul li a:hover::after { transform: scaleX(1); }

.header-actions { display: flex; align-items: center; gap: var(--s-3); justify-self: end; }

.theme-toggle {
  width: 28px; height: 28px;
  display: inline-flex; align-items: center; justify-content: center;
  border: 1px solid var(--rule-2);
  background: var(--paper);
  color: var(--ink);
  font-size: var(--t-12);
  transition: background var(--dur-1) var(--ease-step), color var(--dur-1) var(--ease-step);
}
.theme-toggle:hover { background: var(--ink); color: var(--paper); }

#logout { font-size: var(--t-11); padding: 4px var(--s-3); }

#search-input {
  padding: 4px var(--s-3); border-radius: var(--r-0); border: 1px solid var(--rule-2);
  background: var(--paper); font-family: var(--font-mono); font-size: var(--t-12);
  width: 200px; margin: 0;
}
#search-input:focus { outline: 2px solid var(--mark); outline-offset: -1px; border-color: var(--mark); }

.mobile-menu-toggle {
  display: none;
  background: var(--paper);
  border: 0;
  outline: none;
  -webkit-appearance: none;
  padding: 8px;
  flex-direction: column;
  gap: 4px;
  cursor: pointer;
  align-items: center;
  justify-content: center;
}
.mobile-menu-toggle span {
  width: 18px;
  height: 2px;
  background: var(--ink);
  display: block;
  transition: transform 150ms ease, opacity 150ms ease;
}

@media (max-width: 768px) {
  .header-content {
    grid-template-columns: auto 1fr auto;
    gap: var(--s-3);
    padding: 0 var(--s-4);
  }
  /* Hide desktop nav, search, and header-actions; burger takes over col 3 */
  header:not(.section-header) nav { display: none; }
  #search-input { display: none; }
  #logout { display: none; }
  .logo .logo-meta { display: none; }
  .header-actions { display: none; }
  .mobile-menu-toggle { display: inline-flex; }

  /* Dropdown nav — shown when JS adds .active */
  header:not(.section-header) nav.active {
    display: flex !important;
    position: absolute;
    top: var(--header-height);
    left: 0; right: 0;
    background: var(--paper);
    border-bottom: 2px solid var(--ink);
    z-index: 50;
    padding: var(--s-3) var(--s-5) var(--s-4);
  }
  header:not(.section-header) nav.active ul {
    flex-direction: column;
    gap: 0;
    width: 100%;
  }
  header:not(.section-header) nav.active ul li a {
    display: block;
    padding: var(--s-3) 0;
    font-size: var(--t-14);
    border-bottom: 1px solid var(--rule);
    color: var(--ink);
  }
  header:not(.section-header) nav.active ul li:last-child a { border-bottom: 0; }
  header:not(.section-header) nav.active ul li a::after { display: none; }

  /* Burger active state — turns into an X */
  .mobile-menu-toggle.active span:nth-child(1) {
    transform: translateY(6px) rotate(45deg);
  }
  .mobile-menu-toggle.active span:nth-child(2) { opacity: 0; }
  .mobile-menu-toggle.active span:nth-child(3) {
    transform: translateY(-6px) rotate(-45deg);
  }
}