/* Shared palette, one public header, always-visible navigation. */
.site-topbar{background:var(--announcement-background,var(--teal,#214c49));color:var(--announcement-text,#fff);font-size:12px;letter-spacing:.03em}
.site-topbar-inner{display:grid;grid-template-columns:1fr auto 1fr;align-items:center;gap:20px;min-height:38px;padding:5px clamp(20px,4vw,64px)}
.site-topbar-message{grid-column:2;text-align:center;line-height:1.6}
.site-topbar-login{grid-column:3;justify-self:end;display:inline-flex;align-items:center;gap:8px;color:inherit;text-decoration:none;padding:4px 12px;border:1px solid currentColor;border-radius:999px;font-weight:600;line-height:1.5;white-space:nowrap;transition:background .18s ease,transform .18s ease}
.site-topbar-login:hover{background:#ffffff1a;transform:translateY(-1px)}.site-topbar-login:focus-visible{outline:2px solid currentColor;outline-offset:3px}
.header{display:flex;align-items:center;justify-content:space-between;flex-wrap:nowrap;gap:clamp(18px,2vw,32px);padding:20px clamp(14px,3vw,50px);overflow:visible;border-bottom:1px solid var(--line,#dedfd6);box-shadow:0 3px 14px #182a3204}
.header>.brand{flex:0 0 auto;min-width:0;max-width:none;justify-content:flex-start;gap:12px;white-space:nowrap}.header>.brand img{max-width:55px}.header .brand-name{white-space:nowrap;word-break:normal;overflow-wrap:normal;flex:none}.header .brand-mark{flex:none}
.header nav{display:block!important;flex:1;min-width:0}.header .menu-toggle{display:none!important}
.site-nav-list{display:flex;align-items:center;justify-content:flex-end;gap:clamp(3px,.5vw,9px);list-style:none;padding:0;margin:0}
.site-nav-list>li{position:relative;list-style:none;min-width:0}
.site-nav-list a,.site-nav-list summary{display:block;cursor:pointer;color:inherit;font-size:var(--nav-size,14px);line-height:1.45;text-decoration:none;white-space:normal}
.site-nav-list>li>a,.site-nav-list summary{border-radius:8px;padding:10px 8px;font-weight:500;transition:background .18s ease,color .18s ease,box-shadow .18s ease}
.site-nav-list summary{list-style:none}.site-nav-list summary::-webkit-details-marker{display:none}.site-nav-list summary::after{content:'⌄';display:inline-block;margin-left:5px;color:var(--teal,#214c49);transition:transform .18s ease}
.site-nav-list>li>a:hover,.site-nav-list summary:hover,.site-nav-list>li>a[aria-current],.site-nav-list details[open]>summary{background:var(--sage,#e5ece3);color:var(--teal,#214c49)}
.site-nav-list details[open]>summary::after{transform:rotate(180deg)}
.site-nav-list details>ul{display:none;position:absolute;z-index:110;top:100%;left:0;width:260px;max-width:calc(100vw - 28px);background:var(--surface,#fffdf8);color:var(--ink,#182a32);border:1px solid var(--line,#dedfd6);border-top:2px solid var(--teal,#214c49);border-radius:12px;box-shadow:0 18px 44px #182a3224;padding:8px;list-style:none;margin:0}
.site-nav-list>li:last-child details>ul{left:auto;right:0}.site-nav-list details:hover>ul,.site-nav-list details:focus-within>ul,.is-managed .site-nav-list details[open]>ul{display:block}
.site-nav-list details>ul a{padding:12px 14px;border-radius:8px;font-size:var(--nav-size,14px);line-height:1.6;transition:background .18s ease,transform .18s ease}
.site-nav-list details>ul a:hover,.site-nav-list details>ul a:focus-visible{background:var(--sage,#e5ece3)}.site-nav-list details>ul a:hover{transform:translateX(2px)}
.site-nav-list :focus-visible{outline:2px solid var(--teal,#214c49);outline-offset:3px;border-radius:7px}
@media(min-width:768px) and (max-width:1200px){.header{gap:18px;padding:16px 14px}.header>.brand{font-size:20px;gap:9px}.header>.brand img{max-width:28px}.site-nav-list{gap:3px}.site-nav-list>li{flex:1}.site-nav-list>li[data-menu-item="books"]{flex:1.9}.site-nav-list>li[data-menu-item="tutor"]{flex:1.8}.site-nav-list>li[data-menu-item="research"]{flex:1.6}.site-nav-list>li[data-menu-item="home"]{flex:.65}.site-nav-list>li>a,.site-nav-list summary{padding:10px 5px}.site-nav-list a,.site-nav-list summary{font-size:clamp(11px,1.15vw,var(--nav-size,14px))}.site-nav-list details>ul a{font-size:14px}}
@media(max-width:767px){.site-topbar-inner{grid-template-columns:minmax(0,1fr) auto;gap:12px;padding:6px 20px}.site-topbar-message{grid-column:1;text-align:left;font-size:11px}.site-topbar-login{grid-column:2;padding:4px 10px}.header{display:grid;grid-template-columns:minmax(0,1fr);gap:16px;padding:18px 20px;position:relative!important}.header>.brand{justify-self:start;font-size:25px}.header>.brand img{max-width:44px}.header nav{grid-column:1;width:100%;padding-top:6px;border-top:1px solid var(--line,#dedfd6)}.site-nav-list{display:block}.site-nav-list>li{border-bottom:1px solid var(--line,#dedfd6)}.site-nav-list>li>a,.site-nav-list summary{padding:13px 10px;font-size:var(--nav-size,14px)}.site-nav-list summary{font-weight:600}.site-nav-list summary::after{display:none}.site-nav-list details>ul,.site-nav-list details:not([open])>ul{display:block;position:static;width:auto;max-width:none;box-shadow:none;border:0;border-left:2px solid var(--line,#dedfd6);border-radius:0;background:transparent;margin:0 0 14px 4px;padding:0 0 0 10px}.site-nav-list details>ul a{padding:10px 12px;font-size:var(--nav-size,14px)}.site-nav-list details[open]>summary{background:transparent;color:inherit}}
@media(prefers-reduced-motion:reduce){.site-topbar-login,.site-nav-list>li>a,.site-nav-list summary,.site-nav-list summary::after,.site-nav-list details>ul a{transition:none;transform:none}}