/* 首页顶栏：分组下拉菜单（覆盖 future.css 里平铺横滑的 .cs-header__nav） */
.cs-header__nav.nav-groups {
  overflow: visible;
  gap: clamp(0.4rem, 1.2vw, 0.9rem);
}
.nav-g { position: relative; }
.nav-g__btn {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  background: none;
  border: 0;
  border-bottom: 1px solid transparent;
  color: var(--mut);
  font: inherit;
  padding: 0.3rem 0.35rem;
  cursor: pointer;
  transition: color 0.2s;
}
.nav-g__btn::after {
  content: "";
  width: 0.38rem;
  height: 0.38rem;
  border-right: 1.5px solid currentColor;
  border-bottom: 1.5px solid currentColor;
  transform: translateY(-0.12rem) rotate(45deg);
  transition: transform 0.2s;
  opacity: 0.7;
}
.nav-g:hover .nav-g__btn,
.nav-g.open .nav-g__btn,
.nav-g__btn:focus-visible { color: var(--gold-hi); border-bottom-color: var(--gold); }
.nav-g.open .nav-g__btn::after { transform: translateY(0.08rem) rotate(-135deg); }

.nav-g__menu {
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  padding-top: 0.55rem;            /* 鼠标从按钮移到菜单时不断开 */
  min-width: 11.5rem;
  display: none;
  z-index: 60;
}
.nav-g__menu-in {
  background: rgba(8, 12, 24, 0.97);
  border: 1px solid var(--line-hi, rgba(126, 158, 214, 0.32));
  border-radius: 6px;
  box-shadow: 0 14px 40px rgba(0, 0, 0, 0.55);
  padding: 0.35rem;
  display: flex;
  flex-direction: column;
}
.nav-g.open .nav-g__menu { display: block; }
@media (hover: hover) and (pointer: fine) {
  .nav-g:hover .nav-g__menu { display: block; }
}
.cs-header__nav.nav-groups .nav-g__menu a {
  display: block;
  padding: 0.5rem 0.75rem;
  border: 0;
  border-radius: 4px;
  color: var(--ink);
  white-space: nowrap;
  line-height: 1.35;
}
.nav-g__menu a small {
  display: block;
  font-size: 0.72rem;
  color: var(--mut);
  margin-top: 0.1rem;
}
.cs-header__nav.nav-groups .nav-g__menu a:hover,
.cs-header__nav.nav-groups .nav-g__menu a:focus-visible {
  background: rgba(245, 181, 63, 0.1);
  color: var(--gold-hi);
}
.nav-g__menu a:hover small { color: var(--gold); }

/* 窄屏：导航换到第二行，四个分组均分；菜单贴边展开 */
@media (max-width: 640px) {
  .cs-header { flex-wrap: wrap; row-gap: 0.35rem; }
  .cs-header__nav.nav-groups {
    order: 3;
    width: 100%;
    margin-left: 0;
    justify-content: space-between;
    font-size: 0.9rem;
  }
  .nav-g { position: static; }
  .nav-g__menu {
    left: 0.75rem;
    right: 0.75rem;
    transform: none;
    min-width: 0;
  }
  .nav-g__menu-in { display: grid; grid-template-columns: 1fr 1fr; gap: 0.2rem; }
  .cs-header__nav.nav-groups .nav-g__menu a { white-space: normal; }
}

/* 当前页 */
.cs-header__nav.nav-groups .nav-g__menu a[aria-current="page"] { color: var(--gold); }
.cs-header__nav.nav-groups .nav-g__menu a[aria-current="page"]::before { content: "● "; font-size: 0.6em; vertical-align: 0.2em; }
.nav-g:has(a[aria-current="page"]) .nav-g__btn { color: var(--ink); }