/* ============================================================
   NeuroAtlas · layout.css
   页头（导航栏）/ 页脚 / 移动端菜单
   依赖：css/tokens.css、css/base.css
   ============================================================ */

/* ---------------- 页头 ---------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  border-bottom: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

.header-inner {
  position: relative;
  display: flex;
  align-items: center;
  gap: 18px;
  min-height: 64px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  min-width: 0;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 30px;
  height: 30px;
  flex: none;
  border-radius: 8px;
  background: var(--blue-600);
  color: #fff;
  box-shadow: 0 8px 16px -10px rgba(29, 78, 216, 0.9);
}

.brand-mark svg {
  width: 17px;
  height: 17px;
}

.brand-name {
  display: block;
  font-family: var(--font-mono);
  font-size: 13.5px;
  font-weight: 700;
  letter-spacing: 0.14em;
  line-height: 1.2;
  color: var(--ink-900);
}

.brand-name b {
  color: var(--blue-600);
  font-weight: 700;
}

.brand-sub {
  display: block;
  margin-top: 1px;
  font-size: 10px;
  letter-spacing: 0.08em;
  color: var(--ink-400);
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 2px;
  margin-left: auto;
}

.nav-link {
  padding: 7px 10px;
  border-radius: 7px;
  font-size: 13px;
  color: var(--ink-500);
  transition: color 0.16s ease, background-color 0.16s ease;
}

.nav-link:hover {
  color: var(--ink-900);
  background: var(--surface-soft);
}

.nav-link.is-active {
  color: var(--blue-700);
  background: var(--blue-50);
  font-weight: 600;
}

.header-search {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-left: 8px;
  padding: 6px 11px;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-pill);
  background: var(--surface);
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.04em;
  color: var(--ink-500);
  transition: border-color 0.16s ease, color 0.16s ease;
}

.header-search:hover {
  border-color: var(--blue-500);
  color: var(--blue-600);
}

.header-search svg {
  width: 12px;
  height: 12px;
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: 6px;
  padding: 6px 11px;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-pill);
  background: var(--surface);
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.04em;
  color: var(--ink-500);
}

.nav-toggle__bars {
  display: inline-grid;
  gap: 3px;
}

.nav-toggle__bars span {
  display: block;
  width: 13px;
  height: 1.5px;
  background: currentColor;
}

/* ---------------- 页脚 ---------------- */
.site-footer {
  margin-top: auto;
  border-top: 1px solid var(--line);
  background: var(--surface);
}

.footer-inner {
  display: grid;
  grid-template-columns: minmax(0, 1.4fr) repeat(2, minmax(0, 1fr));
  gap: 28px;
  padding: clamp(32px, 4.5vw, 48px) 0 24px;
}

.footer-brand .brand {
  margin-bottom: 10px;
}

.footer-brand p {
  max-width: 30em;
  color: var(--ink-400);
  font-size: 12.5px;
  line-height: 1.75;
}

.footer-col h3 {
  margin-bottom: 8px;
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-400);
}

.footer-col a {
  display: block;
  padding: 2px 0;
  font-size: 12.5px;
  color: var(--ink-500);
}

.footer-col a:hover {
  color: var(--blue-600);
}

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  flex-wrap: wrap;
  padding: 14px 0 20px;
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.03em;
  color: var(--ink-400);
}

/* ---------------- 移动端 ---------------- */
@media (max-width: 900px) {
  .nav-toggle {
    display: inline-flex;
    margin-left: auto;
  }

  .site-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 2px;
    margin-left: 0;
    padding: 8px 0 12px;
    border-bottom: 1px solid var(--line);
    background: var(--surface);
    box-shadow: var(--shadow-md);
  }

  .site-nav.is-open {
    display: flex;
  }

  .nav-link {
    padding: 9px 12px;
    border-radius: 8px;
  }

  .header-search {
    display: none;
  }
}

@media (max-width: 800px) {
  .footer-inner {
    grid-template-columns: 1fr;
    gap: 20px;
  }
}