/* 常规网站壳层：纸面内容、层级页头与统一导航抽屉。 */
[data-yz-surface="site"] {
  --yz-site-header-height: 4rem;
  --yz-site-paper: var(--canvas);
}

.yz-page-header {
  position: sticky;
  z-index: 200;
  top: 0;
  min-height: var(--yz-site-header-height);
  padding: 0 max(1rem, env(safe-area-inset-right)) 0 max(1rem, env(safe-area-inset-left));
  border-bottom: 1px solid var(--line);
  background: color-mix(in srgb, var(--yz-site-paper) 94%, transparent);
}

.yz-page-header__inner {
  display: grid;
  grid-template-columns: minmax(7rem, 1fr) auto minmax(7rem, 1fr);
  align-items: center;
  width: 100%;
  max-width: 1100px;
  min-height: var(--yz-site-header-height);
  margin: 0 auto;
}

.yz-page-header__brand { display: inline-flex; grid-column: 2; grid-row: 1; justify-self: center; }
.yz-page-header__brand .logo, .yz-page-header__brand.logo { width: auto; height: 2.1rem; aspect-ratio: 915.94 / 905.19; }
.yz-page-header__title { display: none; }

/* 首页是同一导航组件的品牌位变体：菜单和抽屉共用，只在横屏保留左侧 logo。 */
.yz-page-header__inner--home {
  grid-template-columns: auto minmax(0, 1fr);
  max-width: 1180px;
  gap: clamp(2rem, 5vw, 5rem);
}
.yz-page-header--home .yz-page-header__brand { grid-column: 1; justify-self: start; }
.yz-page-header--home .yz-page-header__brand .logo {
  height: 2.35rem;
  transition: transform var(--dur-fast) var(--ease), opacity var(--dur-med) var(--ease);
}
.yz-page-header--home .yz-site-nav { grid-column: 2; justify-self: end; }

.yz-nav-back {
  display: inline-flex;
  grid-column: 1;
  grid-row: 1;
  align-items: center;
  gap: .3rem;
  min-width: 2.75rem;
  min-height: 2.75rem;
  justify-self: start;
  color: var(--muted);
  font-size: .9rem;
  font-weight: 600;
  text-decoration: none;
}

.yz-nav-back::before {
  width: 1rem;
  height: 1rem;
  content: "";
  background: currentColor;
  mask: url("../../assets/icons/arrow-left.svg") center / contain no-repeat;
  -webkit-mask: url("../../assets/icons/arrow-left.svg") center / contain no-repeat;
}

.yz-nav-back:hover { color: var(--focus); }
.yz-nav-back:focus-visible { outline: 2px solid var(--focus); outline-offset: 3px; }

.yz-site-nav {
  display: flex;
  grid-column: 3;
  grid-row: 1;
  align-items: center;
  justify-self: end;
  gap: 1.15rem;
}

.yz-site-nav a { color: var(--muted); font-family: var(--font-hei); font-size: .9rem; font-weight: 500; text-decoration: none; white-space: nowrap; }
.yz-site-nav a:hover { color: var(--text); }
.yz-site-nav__utilities { display: flex; align-items: center; gap: .5rem; }
.yz-site-nav .btn, .yz-site-nav .dropdown-trigger, .yz-site-nav .nav-dropdown-wrapper { flex: 0 0 auto; }

.nav-dropdown-wrapper { position: relative; display: inline-block; }
.dropdown-trigger {
  display: inline-flex;
  align-items: center;
  gap: .28rem;
  padding: 0;
  cursor: pointer;
  user-select: none;
  color: var(--muted);
  font: 500 .9rem var(--font-hei);
  transition: color var(--dur-fast) var(--ease);
}
.dropdown-trigger span { display: none; }
.dropdown-trigger::after {
  width: .8rem;
  height: .8rem;
  content: "";
  display: block;
  background: currentColor;
  mask: url("../../assets/icons/chevron-down.svg") center / contain no-repeat;
  -webkit-mask: url("../../assets/icons/chevron-down.svg") center / contain no-repeat;
  transition: transform var(--dur-fast) var(--ease);
}
.nav-dropdown-wrapper:hover .dropdown-trigger, .nav-dropdown-wrapper:focus-within .dropdown-trigger { color: var(--text); }
.nav-dropdown-wrapper:hover .dropdown-trigger::after, .nav-dropdown-wrapper:focus-within .dropdown-trigger::after { transform: rotate(180deg); }
.dropdown-trigger:focus-visible { outline: 2px solid var(--focus); outline-offset: 3px; }

.nav-dropdown {
  position: absolute;
  z-index: 150;
  top: 100%;
  right: 0;
  min-width: 120px;
  padding: .4rem 0;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--surface-floating);
  box-shadow: var(--shadow-md);
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition: all var(--dur-fast) var(--ease);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}
.nav-dropdown a {
  display: block !important;
  padding: .5rem 1rem;
  color: var(--muted) !important;
  font-size: .86rem !important;
  font-weight: 500 !important;
  text-align: left;
  white-space: nowrap;
  transition: background var(--dur-fast) var(--ease), color var(--dur-fast) var(--ease);
}
.nav-dropdown a:hover { color: var(--focus) !important; background: var(--bg-soft); }
.nav-dropdown-wrapper:hover .nav-dropdown, .nav-dropdown-wrapper:focus-within .nav-dropdown { opacity: 1; visibility: visible; transform: translateY(4px); }

.theme-toggle-btn { position: relative; }
.theme-toggle-btn::before {
  width: 1.2rem;
  height: 1.2rem;
  content: "";
  background: currentColor;
  mask: url("../../assets/icons/moon.svg") center / contain no-repeat;
  -webkit-mask: url("../../assets/icons/moon.svg") center / contain no-repeat;
}
html[data-theme="dark"] .theme-toggle-btn::before {
  mask-image: url("../../assets/icons/sun.svg");
  -webkit-mask-image: url("../../assets/icons/sun.svg");
}
.yz-nav-menu-toggle { display: none; position: relative; }
.yz-nav-menu-toggle::before {
  width: 1.28rem;
  height: 1.28rem;
  content: "";
  background: currentColor;
  mask: url("../../assets/icons/menu.svg") center / contain no-repeat;
  -webkit-mask: url("../../assets/icons/menu.svg") center / contain no-repeat;
}
.yz-page-header.is-menu-open .yz-nav-menu-toggle::before {
  mask-image: url("../../assets/icons/x.svg");
  -webkit-mask-image: url("../../assets/icons/x.svg");
}

.yz-nav-menu-scrim {
  position: fixed;
  z-index: 199;
  inset: 0;
  display: block;
  border: 0;
  background: var(--surface-overlay);
  opacity: 0;
  visibility: hidden;
  cursor: pointer;
  pointer-events: none;
  transition: opacity var(--dur-med) var(--ease), visibility var(--dur-med) var(--ease);
}
.yz-nav-menu-scrim.is-visible { opacity: 1; visibility: visible; pointer-events: auto; }
html.nav-menu-open, body.nav-menu-open { overflow: hidden; }

@media (hover: hover) and (min-width: 60.0625rem) {
  .yz-page-header--home:hover .logo, .yz-page-header--home:focus-within .logo { transform: scale(1.05); }
}

@media (max-width: 60rem) {
  .yz-page-header__inner { grid-template-columns: auto minmax(0, 1fr) auto; }
  .yz-page-header__brand { display: none; }
  .yz-page-header__title { display: block; grid-column: 2; grid-row: 1; margin: 0; overflow: hidden; color: var(--text); font-size: .98rem; font-weight: 700; text-align: center; text-overflow: ellipsis; white-space: nowrap; }
  .yz-nav-back { grid-column: 1; font-size: 0; }
  .yz-nav-back::before { width: 1.15rem; height: 1.15rem; }
  .yz-nav-menu-toggle { display: inline-grid; grid-column: 3; grid-row: 1; justify-self: end; z-index: 202; }

  .yz-page-header__inner--home { grid-template-columns: minmax(0, 1fr) auto; gap: 0; }
  .yz-page-header--home .yz-page-header__brand { display: inline-flex; grid-column: 1; }
  .yz-page-header--home .yz-page-header__brand .logo { height: 2.1rem; }
  .yz-page-header--home .yz-page-header__title { display: none; }
  .yz-page-header--home .yz-nav-menu-toggle { grid-column: 2; }

  .yz-site-nav {
    position: fixed;
    z-index: 201;
    top: 0;
    right: 0;
    display: flex;
    width: min(86vw, 22rem);
    height: 100dvh;
    padding: 5.75rem 1.5rem max(1.5rem, env(safe-area-inset-bottom));
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    overflow-y: auto;
    border-left: 1px solid var(--line);
    background: var(--canvas);
    box-shadow: var(--shadow-lg);
    transform: translateX(100%);
    visibility: hidden;
    pointer-events: none;
    transition: transform var(--dur-med) var(--ease), visibility var(--dur-med) var(--ease);
  }
  .yz-site-nav.is-open { transform: translateX(0); visibility: visible; pointer-events: auto; }
  .yz-site-nav > a { display: flex; min-height: 3.1rem; align-items: center; border-bottom: 1px solid var(--line); color: var(--text); font-size: 1rem; font-weight: 600; }
  .yz-site-nav .nav-dropdown-wrapper { display: block; padding: 1.15rem 0 .75rem; border-bottom: 1px solid var(--line); }
  .yz-site-nav .dropdown-trigger { display: none; }
  .yz-site-nav .nav-dropdown { position: static; display: grid; gap: .1rem; min-width: 0; padding: 0; border: 0; border-radius: 0; background: transparent; box-shadow: none; opacity: 1; visibility: visible; transform: none; backdrop-filter: none; -webkit-backdrop-filter: none; }
  .yz-site-nav .nav-dropdown::before { display: block; margin-bottom: .35rem; color: var(--muted); content: "相关页面"; font-size: .75rem; font-weight: 700; letter-spacing: .1em; }
  .yz-site-nav .nav-dropdown a { min-height: 2.6rem; padding: 0; color: var(--text) !important; font-size: .94rem !important; }
  .yz-site-nav__utilities { display: flex; gap: .75rem; margin-top: auto; padding-top: 1.15rem; border-top: 1px solid var(--line); }
  .yz-site-nav__utilities .theme-toggle-btn { width: 3.25rem; height: 3.25rem; border-radius: var(--radius-sm); }
  .yz-site-nav__utilities .btn { flex: 1 1 auto; width: 100%; min-height: 3.25rem; }
}