.hero-background{background:#eff6fb}
.header{position:relative;z-index:50;display:grid;grid-template-columns:minmax(0,1fr) auto minmax(0,1fr);gap:20px;height:82px}
.header>.brand{justify-self:start}
.header>.header-actions{justify-self:end}
.library-hero{position:relative;isolation:isolate;text-align:center;padding:38px 0 35px}
.hero-background:has(.library-hero){overflow:clip;background:linear-gradient(180deg,#eff6fb 5%,#edf5fb 80%,#f7f9fc)}
.hero-art{position:absolute;inset:-50px -180px -80px;z-index:-1;background:url('/images/study-sprue.webp') center 80%/1370px auto no-repeat;opacity:.14;mix-blend-mode:multiply;mask-image:linear-gradient(90deg,#000,transparent 36%,transparent 65%,#000)}
.library-hero h1{font:400 clamp(34px,4vw,48px)/1.15 var(--heading-font);letter-spacing:-1.7px;margin:0 auto 26px;text-wrap:balance}
.library-hero .search-box{max-width:550px;margin:0 auto 18px;text-align:left;border-color:#d2dfeb;box-shadow:0 8px 30px #294d6d0c}
.library-hero .filter-chips{justify-content:center;max-width:650px;margin-inline:auto}
.library-section{padding-top:24px;padding-bottom:35px}
.library-grid{position:relative;display:grid;grid-template-columns:1fr 1fr;gap:22px;align-items:stretch;align-content:start;overflow:clip;overflow-anchor:none}
.category-group,.category-exit{min-width:0;border:1px solid var(--line);border-radius:14px;background:var(--surface);padding:22px 26px 20px;box-shadow:0 3px 10px #19314903;overflow:hidden}
.group-heading{display:flex;align-items:center;justify-content:center;text-align:center;gap:16px;padding-bottom:17px;border-bottom:1px solid var(--line)}
.group-heading h2{font:400 23px/1.2 var(--heading-font);letter-spacing:-.55px}
.group-rows{display:grid;gap:10px;padding-top:16px}
.course-row{position:relative;isolation:isolate;overflow:hidden;display:flex;align-items:center;justify-content:center;width:min(100%,var(--course-button-width,100%));height:55px;min-height:55px;margin-inline:auto;border:1px solid var(--line);border-radius:10px;background:var(--page);padding:12px 44px;font-size:13px;font-weight:500;line-height:1.5;text-align:center;transition:color .3s ease,border-color .3s ease}
.course-label{position:relative;display:flex;align-items:center;justify-content:center;gap:10px;min-width:0}
.course-size-reference{position:fixed;top:0;left:0;visibility:hidden;pointer-events:none}
.course-size-reference .course-row{width:max-content;max-width:none}
.course-emoji{flex:0 0 28px;text-align:center;font-size:21px;line-height:1.4}
.course-row.math{--course-fill:#6550a5}
.course-row.science{--course-fill:#237766}
.course-row.social{--course-fill:#9a5b25}
.course-row.arts{--course-fill:#8b4f91}
.course-row::before{content:"";position:absolute;inset:0;z-index:-1;border-radius:inherit;background:var(--course-fill);transform:translate(-105%,105%);transition:transform .85s cubic-bezier(.22,1,.36,1)}
.course-row:focus-visible{color:#fff;border-color:var(--course-fill)}
.course-row:focus-visible::before{transform:translate(0,0)}
.course-row:focus-visible .new-tag{background:#fff;color:var(--course-fill)}
@media(hover:hover) and (pointer:fine){
  .course-row:hover{color:#fff;border-color:var(--course-fill)}
  .course-row:hover::before{transform:translate(0,0)}
  .course-row:hover .new-tag{background:#fff;color:var(--course-fill)}
}
.row-title{flex:0 1 auto;min-width:0}
.course-row>.new-tag{position:absolute;top:0;right:0;z-index:1;border-radius:0 0 0 7px;background:var(--course-fill);color:#fff;padding:2px 10px 3px;font-size:9px;font-weight:700;line-height:1.3;letter-spacing:.06em;text-transform:uppercase;pointer-events:none}
.community-section{width:min(940px,84%);display:flex;align-items:center;justify-content:space-between;gap:30px;margin-bottom:45px;padding:32px 38px;border:1px solid #d7e5ef;border-radius:14px;background:#eaf2f8}
.community-sketch{flex-shrink:0;width:125px;text-align:center;transform:rotate(-7deg)}
.community-sketch img{width:65px;height:65px}
.community-sketch span{display:block;margin-top:3px;font:italic 12px var(--heading-font);color:var(--blue)}
.community-copy{flex:1;min-width:0}
.community-section h2{font:400 26px/1.2 var(--heading-font);letter-spacing:-.5px;text-wrap:balance}
.community-copy p{margin-top:8px;max-width:44ch;color:var(--muted);font-size:15px;line-height:1.6}
.community-section .pill-link{margin-left:auto;flex-shrink:0;font-size:12px;gap:13px}

:root[data-theme=dark] .hero-background{background:#1c2936}
:root[data-theme=dark] .hero-background:has(.library-hero){background:linear-gradient(#1c2936,#243a4c 82%,var(--page))}
:root[data-theme=dark] .hero-art{mix-blend-mode:screen;filter:invert(1);opacity:.12}
:root[data-theme=dark] .library-hero .search-box{border-color:var(--line)}
:root[data-theme=dark] .community-section{background:var(--soft);border-color:var(--line)}

@media(min-width:1450px){.library-hero{padding-top:48px;padding-bottom:40px}.hero-art{background-size:1550px}}
@media(max-width:950px){.category-group,.category-exit{padding:21px 20px 20px}.group-heading h2{font-size:21px}.community-section{padding:28px 25px;gap:18px}.community-sketch{width:80px}.community-section h2{font-size:24px}}
@media(max-width:680px){.library-hero{padding-top:25px;padding-bottom:24px}.library-hero h1{font-size:35px;letter-spacing:-1.2px;margin-bottom:22px}.library-hero .filter-chips{max-width:360px;gap:8px}.library-section{padding-top:18px;padding-bottom:25px}.library-grid{grid-template-columns:1fr;gap:18px}.category-group,.category-exit{padding:21px 20px 20px}.group-heading h2{font-size:22px}.course-row{min-height:55px}.community-section{width:calc(100% - 36px);flex-direction:column;align-items:flex-start;gap:20px;padding:27px;margin-bottom:30px}.community-section h2{font-size:26px}.community-section .pill-link{font-size:12px;margin-left:0}.hero-art{inset:10px -90px -30px;background-size:900px;opacity:.09;mask-image:linear-gradient(180deg,transparent 5%,#000 100%)}}

/* Shared navigation, with a native disclosure for the complete course list. */
.header .main-nav{display:flex;align-items:center;justify-content:center;gap:6px;justify-self:center}
.main-nav .nav-link{display:inline-flex;align-items:center;justify-content:center;gap:6px;min-height:42px;padding:8px 12px;border-radius:8px;font-size:13px;font-weight:600;line-height:1.4;white-space:nowrap}
.main-nav .nav-link:is(:hover,:focus-visible),.subjects-menu[open]>summary{color:var(--blue);background:var(--soft)}
.subjects-menu{position:relative}
.subjects-menu>summary{cursor:pointer;list-style:none;transition:color .18s,background .18s}
.subjects-menu>summary::-webkit-details-marker{display:none}
.subjects-menu>summary::marker{content:""}
.nav-chevron{width:14px;height:14px;transition:transform .2s ease}
.subjects-menu[open] .nav-chevron{transform:rotate(180deg)}
.subjects-panel{position:absolute;top:calc(100% + 10px);left:50%;z-index:60;display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:22px 26px;width:min(700px,calc(100vw - 40px));max-height:calc(100dvh - 116px);overflow-y:auto;overscroll-behavior:contain;padding:24px;border:1px solid var(--line);border-radius:14px;background:var(--surface);box-shadow:0 18px 55px #14283d30;transform:translateX(-50%);animation:subjects-open .2s cubic-bezier(.22,1,.36,1)}
.subjects-menu:not([open])>.subjects-panel{display:none}
.subject-group{min-width:0}
.subject-group h3{margin:0 8px 7px;color:var(--muted);font:700 11px/1.5 var(--body-font);letter-spacing:.06em;text-transform:uppercase}
.subjects-panel .subject-link{display:flex;align-items:center;gap:9px;min-height:34px;padding:6px 8px;border-radius:6px;font-size:12px;line-height:1.5}
.subject-link>span{flex:0 0 21px;text-align:center;font-size:16px}
.subjects-panel .subject-link:is(:hover,:focus-visible){background:var(--soft);color:var(--blue)}
@keyframes subjects-open{from{opacity:0;transform:translate(-50%,-7px)}to{opacity:1;transform:translate(-50%,0)}}
@media(max-width:600px){
  .header{height:auto;min-height:104px;grid-template-columns:minmax(0,1fr) auto;gap:10px 16px;padding-block:14px}
  .header>.brand{grid-column:1;grid-row:1}
  .header>.header-actions{grid-column:2;grid-row:1}
  .header .main-nav{grid-column:1/-1;grid-row:2;gap:10px}
  .main-nav .nav-link{min-height:38px;padding:8px 13px}
  .subjects-panel{grid-template-columns:minmax(0,1fr);width:min(360px,calc(100vw - 36px));max-height:calc(100dvh - 170px);padding:18px;gap:18px}
}

.category-exit{z-index:2;pointer-events:none}