.site-header.shared-header {
        position: sticky;
        top: 0;
        z-index: 30;
        background: var(--background);
        border-bottom: 1px solid var(--line);
      }

      .header-inner {
        align-items: center;
        display: flex;
        flex-wrap: wrap;
        gap: 12px;
        width: var(--site-content-width);
        margin: 0 auto;
        min-height: 72px;
        padding-block: 12px;
      }

      .shared-header .brand {
        align-items: center;
        display: inline-flex;
        gap: 10px;
        min-height: 44px;
        max-width: 100%;
        text-decoration: none;
      }

      .shared-header .brand:focus-visible {
        outline: 2px solid var(--foreground);
        outline-offset: 4px;
        border-radius: 4px;
      }

      .header-nav {
        display: flex;
        align-items: center;
        gap: 4px;
        margin-left: auto;
      }

      .header-nav a,
      .guides-toggle {
        align-items: center;
        color: var(--foreground);
        display: inline-flex;
        font-size: 0.9375rem;
        font-weight: 600;
        font-family: inherit;
        line-height: 1.4;
        border-radius: 6px;
        min-height: 44px;
        padding: 10px 12px;
        text-decoration: none;
      }

      @media (any-hover: hover) and (any-pointer: fine) {
        html:not([data-pointer-type="touch"]):not([data-pointer-type="pen"]) .header-nav a:hover,
        html:not([data-pointer-type="touch"]):not([data-pointer-type="pen"]) .guides-toggle:hover {
          background: var(--nav-surface);
          text-decoration: none;
        }
      }

      .header-nav a:focus-visible,
      .guides-toggle:focus-visible,
      .submenu-back:focus-visible,
      .menu-toggle:focus-visible {
        outline: 2px solid var(--foreground);
        outline-offset: 4px;
        border-radius: 4px;
      }

      [hidden] { display: none !important; }

      .guides-item { position: relative; }
      .guides-toggle {
        display: none;
        background: transparent;
        border: 0;
        font-family: inherit;
        cursor: pointer;
        gap: var(--site-space-label);
      }
      html[data-menu-ready] .guides-toggle { display: inline-flex; }
      html[data-menu-ready] .guides-fallback { display: none; }
      .guides-toggle svg { width: 16px; height: 16px; }
      .guides-submenu {
        display: grid;
        gap: var(--site-space-label);
        position: absolute;
        top: calc(100% + 8px);
        left: 50%;
        transform: translateX(-50%);
        width: min(360px, calc(100vw - 40px));
        padding: var(--site-space-label);
        border: 1px solid var(--line);
        border-radius: 8px;
        background: var(--background);
        box-shadow: 0 3px 12px rgba(0, 0, 0, 0.16);
        max-height: calc(100dvh - var(--header-height) - 24px);
        overflow-y: auto;
      }
      .guides-item:has(.guides-submenu:not([hidden]))::before {
        content: "";
        position: absolute;
        top: 100%;
        left: 50%;
        transform: translateX(-50%);
        width: min(360px, calc(100vw - 40px));
        height: 10px;
      }
      .guides-submenu a {
        justify-content: space-between;
        gap: 16px;
        display: flex;
        width: 100%;
        font-weight: 600;
        border-radius: 6px;
        overflow-wrap: anywhere;
      }
      .guides-submenu a span[aria-hidden] { flex-shrink: 0; }
      @media (any-hover: hover) and (any-pointer: fine) {
        html:not([data-pointer-type="touch"]):not([data-pointer-type="pen"]) .guides-submenu a:hover {
          background: var(--nav-surface);
          text-decoration: none;
        }
      }
      .submenu-back, .guides-submenu h2 { display: none; }

      .menu-toggle {
        display: none;
        align-items: center;
        justify-content: center;
        background: transparent;
        border: 0;
        color: var(--foreground);
        cursor: pointer;
        padding: 10px;
        min-width: 44px;
        min-height: 44px;
        flex-shrink: 0;
      }

      .menu-icon-close,
      .menu-toggle[aria-expanded="true"] .menu-icon-open {
        display: none;
      }

      .menu-toggle[aria-expanded="true"] .menu-icon-close {
        display: block;
      }

      body.menu-open {
        overflow: hidden;
      }

      @media (min-width: 681px) {
        .header-inner {
          display: grid;
          grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr);
        }

        .shared-header .brand {
          justify-self: start;
        }

        .header-nav {
          margin-left: 0;
          justify-self: center;
        }

        .header-download {
          justify-self: end;
        }
      }

      @media (max-width: 680px) {
        .header-inner {
          display: grid;
          grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr);
          gap: 8px;
        }

        .shared-header .brand {
          gap: 7px;
          grid-column: 2;
          grid-row: 1;
          justify-self: center;
          min-width: 44px;
          justify-content: center;
        }

        .shared-header .brand-mark {
          width: clamp(12px, 3.75vw, 15px);
        }

        .shared-header .brand-word {
          display: none;
        }

        .shared-header .brand picture:has(.brand-word) {
          display: none;
        }

        .header-download {
          margin-left: 0;
          grid-column: 1;
          grid-row: 1;
          justify-self: start;
          padding-inline: 8px;
          font-size: 0.875rem;
        }

        html[data-menu-capable] .shared-header .header-download {
          white-space: nowrap;
        }

        .menu-toggle {
          display: inline-flex;
          grid-column: 3;
          grid-row: 1;
          justify-self: end;
        }

        html:not([data-menu-capable]) .menu-toggle {
          visibility: hidden;
        }

        html:not([data-menu-capable]) .header-nav {
          display: block;
          grid-column: 3;
          grid-row: 1;
          justify-self: end;
          margin: 0;
          z-index: 1;
        }

        .header-inner[data-header-wrap] {
          grid-template-columns: minmax(0, 1fr) auto;
        }

        .header-inner[data-header-wrap] .brand {
          grid-column: 1 / -1;
          grid-row: 2;
        }

        html[data-menu-capable] .header-inner[data-header-wrap] .header-download {
          max-width: 100%;
          white-space: normal;
          overflow-wrap: anywhere;
        }

        .header-inner[data-header-wrap] .menu-toggle,
        html:not([data-menu-capable]) .header-inner[data-header-wrap] .header-nav {
          grid-column: 2;
        }

        .header-nav {
          display: none;
        }

        /* Keep the sticky header in flow and the overlay opaque throughout opening. */
        html[data-menu-ready] body.menu-open .header-nav {
          display: block;
          position: fixed;
          inset: var(--header-height) 0 0;
          margin: 0;
          padding: 24px 20px max(40px, env(safe-area-inset-bottom));
          background: var(--background);
          overflow-y: auto;
          overscroll-behavior: contain;
        }

        html[data-menu-ready] body.menu-open .guides-toggle {
          animation: menu-in 220ms ease;
        }

        html[data-menu-ready] .guides-toggle {
          display: flex;
          width: 100%;
          min-height: 48px;
          justify-content: space-between;
          border-bottom: 1px solid var(--line);
          padding-inline: 0;
        }

        html[data-menu-ready] .guides-submenu {
          display: block;
          position: fixed;
          inset: var(--header-height) 0 0;
          width: auto;
          max-height: none;
          transform: none;
          border: 0;
          border-radius: 0;
          box-shadow: none;
          padding: 24px 20px max(40px, env(safe-area-inset-bottom));
          overscroll-behavior: contain;
        }

        html[data-menu-ready] .guides-submenu > * {
          animation: submenu-in 220ms ease;
        }

        .submenu-back {
          display: inline-flex;
          align-items: center;
          gap: 8px;
          min-height: 44px;
          padding: 0 12px 0 0;
          background: transparent;
          border: 0;
          color: var(--foreground);
          font-family: inherit;
          font-size: 0.9375rem;
          font-weight: 600;
          line-height: 1.4;
          cursor: pointer;
        }
        .guides-submenu h2 {
          display: block;
          margin: 24px 0 20px;
          font-size: 1.75rem;
          font-weight: 700;
          line-height: 1.25;
          letter-spacing: -0.025em;
        }
        .guides-item::before { display: none; }

        .header-nav a {
          display: flex;
          width: 100%;
          min-height: 48px;
          border-bottom: 1px solid var(--line);
          padding-inline: 0;
        }

        .header-nav:has(.guides-submenu:not([hidden])) > .header-nav-link {
          display: none;
        }

        .guides-submenu a {
          min-height: 48px;
          padding: 12px 14px;
          border-bottom: 0;
          border-radius: 6px;
          margin-block: 8px;
        }

        @media (any-hover: hover) and (any-pointer: fine) {
          html:not([data-pointer-type="touch"]):not([data-pointer-type="pen"]) .guides-submenu a:hover {
            text-decoration: none;
          }
        }
      }

      @keyframes submenu-in {
        from { opacity: 0; transform: translateX(24px); }
        to { opacity: 1; transform: translateX(0); }
      }

      @keyframes menu-in {
        from { opacity: 0; transform: translateY(-8px); }
        to { opacity: 1; transform: translateY(0); }
      }

      @media (prefers-reduced-motion: reduce) {
        html[data-menu-ready] body.menu-open .guides-toggle,
        html[data-menu-ready] .guides-submenu > * {
          animation: none;
        }
      }

      .header-download {
        align-items: center;
        background: var(--foreground);
        border: 1px solid var(--foreground);
        border-radius: 5rem;
        color: var(--background);
        display: inline-flex;
        flex-shrink: 0;
        font-size: 0.9375rem;
        font-weight: 600;
        justify-content: center;
        line-height: 1.4;
        min-height: 44px;
        padding: 10px 14px;
        text-decoration: none;
      }

      @media (any-hover: hover) and (any-pointer: fine) {
        html:not([data-pointer-type="touch"]):not([data-pointer-type="pen"]) .header-download:hover {
          background: #252727;
          border-color: #252727;
        }
      }

      @media (prefers-color-scheme: dark) {
        @media (any-hover: hover) and (any-pointer: fine) {
          html:not([data-pointer-type="touch"]):not([data-pointer-type="pen"]) .header-download:hover {
            background: #f2f2f2;
            border-color: #f2f2f2;
          }
        }
      }

      .header-download:focus-visible,
      html[data-input-mode="keyboard"] .header-download:focus {
        border-radius: 5rem;
        outline: 2px solid var(--foreground);
        outline-offset: 4px;
      }

      .shared-header .brand picture {
        min-width: 0;
      }

      .shared-header picture,
      .shared-header img {
        display: block;
      }

      .shared-header .brand-mark {
        height: auto;
        width: clamp(15px, 2.4vw, 19px);
        max-width: 100%;
      }

      .shared-header .brand-word {
        height: auto;
        width: clamp(136px, 21.8vw, 172px);
        max-width: 100%;
      }


.site-header.shared-header { max-width: none; margin: 0; padding: 0; }

@media print { .site-header.shared-header { display: none; } }