/* header.css: brand, navigation, dropdowns, theme toggle, mobile menu */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--header-bg);
  border-bottom: 1px solid var(--border);
  transition: box-shadow var(--t-med) var(--ease);
}
.site-header.is-stuck { box-shadow: var(--shadow-md); }

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  min-height: var(--header-h);
}

/* ---------- Brand ---------- */
.brand { display: flex; flex-direction: column; line-height: 1.2; text-decoration: none; }
.brand:hover { color: var(--heading); }
.brand__name { font-size: 1.2rem; font-weight: 800; letter-spacing: -0.02em; color: var(--heading); }
.brand__tag {
  margin-top: 0.2rem;
  font-size: 0.66rem;
  font-weight: 700;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent);
}

/* ---------- Header buttons ---------- */
.header-actions { display: flex; align-items: center; gap: 0.5rem; }

.theme-toggle,
.nav-toggle {
  align-items: center;
  justify-content: center;
  width: 2.75rem;
  height: 2.75rem;
  padding: 0;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: transparent;
  color: var(--heading);
  cursor: pointer;
  transition: background-color var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease);
}
.theme-toggle:hover,
.nav-toggle:hover { background: var(--highlight); border-color: var(--accent); }

.nav-toggle { display: inline-flex; }

/* The theme toggle needs JavaScript, so it stays hidden until init.js adds "js" */
.theme-toggle { display: none; }
.js .theme-toggle { display: inline-flex; }

.theme-toggle svg { width: 1.25rem; height: 1.25rem; }
.theme-toggle__sun { display: none; }
[data-theme='dark'] .theme-toggle__sun { display: block; }
[data-theme='dark'] .theme-toggle__moon { display: none; }

.nav-toggle__bars,
.nav-toggle__bars::before,
.nav-toggle__bars::after {
  display: block;
  width: 1.25rem;
  height: 2px;
  background: currentColor;
  transition: transform var(--t-med) var(--ease), opacity var(--t-med) var(--ease);
}
.nav-toggle__bars { position: relative; }
.nav-toggle__bars::before,
.nav-toggle__bars::after { content: ''; position: absolute; left: 0; }
.nav-toggle__bars::before { top: -6px; }
.nav-toggle__bars::after { top: 6px; }
.nav-toggle.is-open .nav-toggle__bars { background: transparent; }
.nav-toggle.is-open .nav-toggle__bars::before { transform: translateY(6px) rotate(45deg); }
.nav-toggle.is-open .nav-toggle__bars::after { transform: translateY(-6px) rotate(-45deg); }

/* ---------- Mobile navigation panel ---------- */
.site-nav {
  display: none;
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  max-height: calc(100vh - var(--header-h));
  max-height: calc(100dvh - var(--header-h));
  overflow-y: auto;
  background: var(--header-bg);
  border-bottom: 1px solid var(--border);
  box-shadow: var(--shadow-md);
}
.site-nav.is-open { display: block; animation: nav-in var(--t-med) var(--ease); }
@keyframes nav-in {
  from { opacity: 0; transform: translateY(-6px); }
  to { opacity: 1; transform: none; }
}

.site-nav__list { list-style: none; padding: 0.5rem var(--gutter) 1rem; }

.nav-link {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  min-height: 3rem;
  padding: 0.75rem 0;
  border: 0;
  border-bottom: 1px solid var(--border);
  background: none;
  font: inherit;
  font-weight: 600;
  color: var(--heading);
  text-align: left;
  text-decoration: none;
  cursor: pointer;
}
.nav-link:hover { color: var(--link); }
.nav-link[aria-current='page'],
.nav-dropdown.is-active > .nav-link { color: var(--link); }

.nav-chevron { flex-shrink: 0; transition: transform var(--t-fast) var(--ease); }
.nav-dropdown.is-open .nav-chevron { transform: rotate(180deg); }

.nav-dropdown__menu { display: none; list-style: none; padding: 0 0 0.5rem 1rem; }
.nav-dropdown.is-open .nav-dropdown__menu { display: block; }
.nav-dropdown__menu a { display: block; min-height: 2.75rem; padding: 0.6rem 0; color: var(--text); text-decoration: none; }
.nav-dropdown__menu a:hover { color: var(--link); text-decoration: underline; }
.nav-dropdown__menu a[aria-current='page'] { font-weight: 700; color: var(--link); }

/* ---------- Desktop navigation ---------- */
@media (min-width: 68rem) {
  .nav-toggle { display: none; }

  .site-nav {
    display: block;
    position: static;
    max-height: none;
    margin-left: auto;
    overflow: visible;
    border: 0;
    background: none;
    box-shadow: none;
    animation: none;
  }

  .site-nav__list { display: flex; align-items: center; gap: 0.1rem; padding: 0; }
  .nav-item { position: relative; }

  .nav-link {
    gap: 0.35rem;
    width: auto;
    min-height: 0;
    padding: 0.5rem 0.7rem;
    border: 0;
    border-radius: var(--radius);
    font-size: 0.93rem;
    white-space: nowrap;
    transition: background-color var(--t-fast) var(--ease), color var(--t-fast) var(--ease);
  }
  .nav-link:hover { background: var(--highlight); color: var(--heading); }
  .nav-link[aria-current='page'],
  .nav-dropdown.is-active > .nav-link { box-shadow: inset 0 -2px 0 var(--accent); color: var(--heading); }

  .nav-dropdown__menu {
    display: block;
    position: absolute;
    top: calc(100% + 0.4rem);
    left: 0;
    min-width: 16rem;
    padding: 0.4rem;
    background: var(--surface-2);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-4px);
    transition: opacity var(--t-fast) var(--ease), transform var(--t-fast) var(--ease), visibility 0s linear var(--t-fast);
  }
  .nav-dropdown.is-open .nav-dropdown__menu { opacity: 1; visibility: visible; transform: none; transition-delay: 0s; }

  .nav-dropdown__menu a { min-height: 0; padding: 0.55rem 0.75rem; border-radius: var(--radius-sm); }
  .nav-dropdown__menu a:hover { background: var(--highlight); color: var(--heading); text-decoration: none; }

  .nav-item--login { margin-left: 0.5rem; }
  .nav-item--login .nav-link { border: 1px solid var(--btn-outline); color: var(--btn-outline); box-shadow: none; }
  .nav-item--login .nav-link:hover { background: var(--btn-bg); border-color: var(--btn-bg); color: var(--btn-text); }
}