/*
 * Header — 80px tall, translucent white over the hero image.
 * Measured: bg rgba(255,255,255,.75) (α ≈ 0.744, no backdrop blur).
 *
 * ui/首页-关于我们.png replaces the old "logo left, nav flush right" bar with
 * one centred group: logo 100×39 at x420, then six equal 145px columns spanning
 * x633–1503, so logo + nav together centre on the 1920 canvas. Each item stacks a
 * 12px English line over the 16px Chinese one, both centred in the column
 * (measured centres 705.5 / 849.75 / 994 / 1137.75 / 1284.5 / 1431).
 */

.site-header {
  position: fixed;
  inset: 0 0 auto;
  z-index: 100;
  height: var(--header-height);
  overflow: visible;
  background: var(--c-header-bg);
  transition: background-color 260ms ease;
}

body[data-page="home"] .site-header {
  background: transparent;
}

body[data-page="home"] .site-header.is-scrolled {
  background: var(--c-header-bg);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 113px; /* logo right edge 519 → first nav column at 633 */
  height: 100%;
}

.site-header__logo {
  flex: none;
  display: block;
}

.site-header__logo img {
  width: 100px;
  height: 39px;
}

.site-nav {
  position: relative;
  overflow: visible;
}

.site-nav__list {
  position: relative;
  z-index: 1;
  display: flex;
  align-items: center;
}

.site-nav__link {
  position: relative;
  z-index: 1;
  display: flex;
  justify-content: center;
  width: var(--nav-column, 145px);
  color: var(--c-black);
  line-height: 1;
}

/*
 * The label is the measured box, not the column: the hover capsule is sized from
 * it, and it is what has to sit centred whichever of the two lines is wider.
 */
.site-nav__label {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px; /* EN ink top y25, CN ink top y42 within the 80px bar */
}

.site-nav__en {
  font-size: 12px;
  font-weight: var(--fw-regular);
  white-space: nowrap;
}

.site-nav__cn {
  font-size: var(--fs-nav);
  font-weight: var(--fw-regular);
  white-space: nowrap;
}

.site-nav__item.is-current .site-nav__link {
  color: var(--c-red);
}

/* hover glass capsule (全局备注: “hover 悬浮: 出现滑块”) */
.site-nav__slider {
  --glass-x: 0;
  --glass-w: 0;
  position: absolute;
  top: 50%;
  left: 0;
  z-index: 0;
  width: var(--glass-w);
  height: 44px;
  overflow: visible;
  opacity: 0;
  transform: translateX(var(--glass-x)) translateY(-50%);
  transition:
    transform 420ms cubic-bezier(0.34, 1.15, 0.64, 1),
    width 420ms cubic-bezier(0.34, 1.15, 0.64, 1),
    opacity 160ms var(--ease-out);
  pointer-events: none;
}

.site-nav__glass-body {
  position: absolute;
  inset: 0;
  z-index: 0;
  overflow: hidden;
  border: 1px solid rgb(214 214 214 / 36%);
  border-radius: 999px;
  background: rgb(255 255 255 / 16%);
  box-shadow:
    inset 0 1px 0 rgb(255 255 255 / 40%),
    0 4px 16px rgb(0 0 0 / 6%);
  transform-origin: center center;
  transition: transform 420ms cubic-bezier(0.34, 1.15, 0.64, 1);
  backdrop-filter: blur(14px) saturate(135%);
  -webkit-backdrop-filter: blur(14px) saturate(135%);
}

.site-nav__glass-fill {
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background:
    linear-gradient(135deg, rgb(255 255 255 / 58%) 0%, rgb(255 255 255 / 0) 46%),
    linear-gradient(
      180deg,
      rgb(255 255 255 / 78%) 0%,
      rgb(238 238 238 / 70%) 48%,
      rgb(224 224 224 / 66%) 100%
    );
  box-shadow: inset 0 1px 0 rgb(255 255 255 / 82%);
  transform: translateX(-110%);
}

.site-nav.has-slider.is-filled .site-nav__glass-fill {
  transform: translateX(0);
}

.site-nav.has-slider.is-filling[data-glass-direction='ltr'] .site-nav__glass-fill {
  animation: nav-fill-ltr 520ms cubic-bezier(0.22, 0.82, 0.28, 1) both;
}

.site-nav.has-slider.is-filling[data-glass-direction='rtl'] .site-nav__glass-fill {
  animation: nav-fill-rtl 520ms cubic-bezier(0.22, 0.82, 0.28, 1) both;
}

.site-nav__glass-fill::after {
  content: "";
  position: absolute;
  top: 5px;
  right: 18%;
  left: 14%;
  height: 9px;
  border-radius: 999px;
  background: linear-gradient(180deg, rgb(255 255 255 / 70%), rgb(255 255 255 / 0));
}

.site-nav.has-slider .site-nav__slider {
  opacity: 1;
  transform: translateX(var(--glass-x)) translateY(-50%);
}

.site-nav.has-slider.is-moving:not(.is-filling) .site-nav__glass-body {
  transform: scaleX(1.04) scaleY(0.97);
}

.site-nav.has-slider.is-moving[data-glass-direction='rtl'] .site-nav__glass-body {
  transform-origin: right center;
}

.site-nav.has-slider.is-moving[data-glass-direction='ltr'] .site-nav__glass-body {
  transform-origin: left center;
}

@keyframes nav-fill-ltr {
  0% {
    transform: translateX(-110%);
  }

  78% {
    transform: translateX(2%);
  }

  100% {
    transform: translateX(0);
  }
}

@keyframes nav-fill-rtl {
  0% {
    transform: translateX(110%);
  }

  78% {
    transform: translateX(-2%);
  }

  100% {
    transform: translateX(0);
  }
}

@media (prefers-reduced-motion: reduce) {
  html:not(.force-motion) .site-nav.has-slider.is-filling .site-nav__glass-fill {
    animation: none;
    transform: translateX(0);
  }

  html:not(.force-motion) .site-nav__slider {
    transition: opacity 50ms var(--ease-out);
  }

  html:not(.force-motion) .site-nav.has-slider .site-nav__slider,
  html:not(.force-motion) .site-nav.has-slider.is-moving .site-nav__slider {
    transform: translateX(var(--glass-x)) translateY(-50%);
  }

  html:not(.force-motion) .site-nav.has-slider .site-nav__glass-body,
  html:not(.force-motion) .site-nav.has-slider.is-moving .site-nav__glass-body {
    transform: scale(1);
  }
}

/*
 * The 145px columns only fit the 1920 canvas: logo + gap + nav needs 1083px, more
 * than a 1280 viewport leaves once the gutters are taken off. Below that the
 * columns collapse to their content and the gap closes instead of the row wrapping.
 */
@media (max-width: 1320px) {
  .site-header__inner {
    gap: clamp(24px, 4vw, 113px);
  }

  .site-nav__link {
    --nav-column: auto;

    padding: 0 clamp(8px, 1vw, 16px);
  }
}

.site-header__toggle {
  display: none;
  width: 40px;
  height: 40px;
  place-items: center;
}

.site-header__toggle-bar,
.site-header__toggle-bar::before,
.site-header__toggle-bar::after {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--c-black);
  transition: transform var(--dur) var(--ease-out), opacity var(--dur) var(--ease-out);
}

.site-header__toggle-bar::before,
.site-header__toggle-bar::after {
  content: '';
  position: relative;
}

.site-header__toggle-bar::before {
  top: -7px;
}

.site-header__toggle-bar::after {
  top: 5px;
}

[aria-expanded='true'] .site-header__toggle-bar {
  transform: rotate(45deg);
}

[aria-expanded='true'] .site-header__toggle-bar::before {
  opacity: 0;
}

[aria-expanded='true'] .site-header__toggle-bar::after {
  top: -2px;
  transform: rotate(-90deg);
}

@media (max-width: 900px) {
  /* The desktop bar is one centred logo+nav group. Once the panel unhooks the
   * nav, that same justify-content would park the logo and the toggle as a
   * pair in the middle of the 390 canvas. */
  .site-header__inner {
    justify-content: space-between;
    gap: 0;
  }

  .site-header__toggle {
    display: grid;
    order: 2;
  }

  .site-nav {
    position: absolute;
    inset: var(--header-height) 0 auto;
    order: 3;
    max-height: 0;
    overflow: hidden;
    background: var(--c-white);
    transition: max-height var(--dur) var(--ease-out);
  }

  .site-nav.is-open {
    max-height: 60vh;
    box-shadow: 0 12px 24px rgb(0 0 0 / 8%);
  }

  .site-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 8px var(--page-gutter) 20px;
  }

  .site-nav__link {
    justify-content: flex-start;
    width: auto;
    padding: 12px 0;
  }

  /* Stacked in a panel there is room for both lines side by side. */
  .site-nav__label {
    flex-direction: row;
    align-items: baseline;
    gap: 10px;
  }

  .site-nav__slider {
    display: none;
  }
}