@charset "utf-8";
/* header.css · 顶栏、导航和移动菜单 */

.nav-sentinel {
  position: absolute;
  inset-block-start: 0;
  inset-inline-start: 0;
  width: 1px;
  height: 1px;
  pointer-events: none;
  visibility: hidden;
}

.site-nav {
  position: fixed;
  inset-block-start: 0;
  inset-inline: 0;
  z-index: 100;
  height: var(--nav-h);
  border-block-end: 1px solid var(--line);
  background: var(--bg);
}

.site-nav.is-condensed,
.site-nav[data-open="true"] {
  height: var(--nav-h);
  background: var(--bg);
  border-block-end-color: var(--line);
}

.site-nav__inner {
  height: 100%;
  width: 100%;

  max-width: 1440px;
  margin-inline: auto;
  padding-inline: var(--gutter);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--s-5);
}

.site-nav__links {
  display: flex;
  align-items: center;
  gap: clamp(14px, 2.2vw, 32px);
}

.nav-link {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding-block: 9px;
  font-size: 14px;
  line-height: 1.2;
  color: var(--fg-2);
  white-space: nowrap;
  transition: color 0.25s var(--ease);
}

.nav-link::after {
  content: "";
  position: absolute;
  inset-inline: 0;
  inset-block-end: 0;
  height: 2px;
  background: var(--accent);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 0.34s var(--ease);
}

.nav-link:hover {
  color: var(--fg);
}

.nav-link:hover::after,
.nav-link:focus-visible::after {
  transform: scaleX(1);
}

.nav-link[aria-current="page"] {
  color: var(--fg);
}

.nav-link[aria-current="page"]::after {
  transform: scaleX(1);
}

.nav-toggle {
  display: none;
  width: 40px;
  height: 40px;
  margin-inline-end: -8px;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius);
  color: var(--fg);
  transition: background-color 0.25s var(--ease);
}

.nav-toggle:hover {
  background: var(--bg-elevated);
}

.nav-toggle .icon {
  width: 22px;
  height: 22px;
}

.nav-toggle__close {
  display: none;
}

.nav-toggle[aria-expanded="true"] .nav-toggle__open {
  display: none;
}

.nav-toggle[aria-expanded="true"] .nav-toggle__close {
  display: block;
}

:root[data-theme="dark"] .site-nav,
:root[data-theme="dark"] .site-nav.is-condensed,
:root[data-theme="dark"] .site-nav[data-open="true"],
:root[data-theme="dark"] .site-nav[data-open="true"].is-condensed {
  background: var(--bg-raised);
}

@keyframes xu-menu-in {
  from {
    opacity: 0;
    translate: 0 14px;
  }
  to {
    opacity: 1;
    translate: 0 0;
  }
}

@media (max-width: 768px) {
  .site-nav,
  .site-nav.is-condensed,
  .site-nav[data-open="true"] {
    height: var(--nav-h);
  }

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

  .site-nav[data-open="true"],
  .site-nav[data-open="true"].is-condensed {
    background: var(--bg);
    border-block-end-color: transparent;
    -webkit-backdrop-filter: none;
    backdrop-filter: none;
  }

  .site-nav__links {
    position: fixed;
    inset-block-start: var(--nav-h);
    inset-inline: 0;
    inset-block-end: 0;
    z-index: 99;
    flex-direction: column;
    align-items: stretch;
    justify-content: flex-start;
    gap: 0;
    padding: var(--s-5) var(--gutter) var(--s-8);
    background: var(--bg);
    border-block-start: 1px solid var(--line-soft);
    overflow-y: auto;
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transform: translateY(-10px);
    transition:
      opacity 0.3s var(--ease),
      transform 0.3s var(--ease),
      visibility 0.3s linear;
  }

  .site-nav[data-open="true"] .site-nav__links {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    transform: none;
  }

  .nav-link {
    padding-block: var(--s-5);
    font-size: 20px;
    border-block-end: 1px solid var(--line-soft);
  }

  .nav-link::after {
    display: none;
  }

  .nav-link[aria-current="page"] {
    color: var(--accent);
  }

  .nav-link .icon {
    width: 20px;
    height: 20px;
  }

  .site-nav[data-open="true"] .nav-link {
    animation: xu-menu-in 0.42s var(--ease) both;
  }

  .site-nav[data-open="true"] .nav-link:nth-child(1) {
    animation-delay: 0.04s;
  }

  .site-nav[data-open="true"] .nav-link:nth-child(2) {
    animation-delay: 0.09s;
  }

  .site-nav[data-open="true"] .nav-link:nth-child(3) {
    animation-delay: 0.14s;
  }

  .site-nav[data-open="true"] .nav-link:nth-child(4) {
    animation-delay: 0.19s;
  }

  .site-nav[data-open="true"] .nav-link:nth-child(5) {
    animation-delay: 0.24s;
  }
}

@media (max-width: 768px) {
  html:not(.js) .site-nav {
    position: static;
    height: auto;
  }

  html:not(.js) .site-nav__inner {
    flex-wrap: wrap;
    padding-block: var(--s-4);
  }

  html:not(.js) .nav-toggle {
    display: none;
  }

  html:not(.js) .site-nav__links {
    position: static;
    flex-direction: row;
    flex-wrap: wrap;
    gap: var(--s-4);
    padding: 0;
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    transform: none;
    border: 0;
    background: transparent;
  }

  html:not(.js) .nav-link {
    font-size: 14px;
    padding-block: var(--s-2);
    border: 0;
    animation: none;
  }
}

html.is-menu-open,
html.is-menu-open body {
  overflow: hidden;
}