/* Quiet, readable learning layout; shared by the index, notes and quizzes. */
*{box-sizing:border-box}
body{font-family:"Noto Sans KR",-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;background:#fff;background-image:none;color:#20262e;line-height:1.75}
a:focus-visible,button:focus-visible,[tabindex]:focus-visible{outline:3px solid #126653;outline-offset:3px}
.learning-index{margin:0;padding:0}
.site-header{border-bottom:1px solid #d7dbdf}
.site-header nav{max-width:1000px;margin:auto;padding:0 24px;display:flex;align-items:center;gap:40px;min-height:80px}
.site-header a{text-decoration:none;color:#39434d;font-weight:600}
.site-header .site-brand{font-size:19px;color:#20262e;white-space:nowrap}
.subject-nav{display:flex;align-items:stretch;gap:24px}
.subject-nav a{display:flex;align-items:center;min-height:80px;border-bottom:3px solid transparent;white-space:nowrap}
.subject-nav a[aria-current="page"]{color:#075744;border-color:#075744}
.learning-main{max-width:1000px;margin:auto;padding:32px 24px 48px}
.page-heading{margin-bottom:28px}
.page-heading h1{font-size:36px;line-height:1.3;margin:0 0 4px;font-weight:750;letter-spacing:-.8px}
.page-heading p{margin:6px 0;color:#56616d;font-size:16px}
.page-heading .english-label{font-size:20px}
.chapter-list{list-style:none;margin:0;padding:0;border-top:1px solid #d7dbdf}
.chapter-row{display:grid;grid-template-columns:44px minmax(0,1fr) auto;gap:20px;align-items:center;padding:17px 0;border-bottom:1px solid #d7dbdf}
.chapter-number{font-size:22px;font-weight:600;color:#075744}
.chapter-copy h2{font-size:19px;line-height:1.45;margin:0;font-weight:650;overflow-wrap:anywhere}
.chapter-copy p{font-size:14px;line-height:1.5;color:#56616d;margin:3px 0 0}
.chapter-actions{display:flex;gap:8px}
.chapter-actions a,.learning-links a{min-height:44px;display:inline-flex;align-items:center;justify-content:center;text-decoration:none;font-size:16px;font-weight:600;padding:7px 17px;color:#075744;border:1px solid #aab3ba;border-radius:4px;background:#fff;white-space:nowrap}
.chapter-actions a:hover,.learning-links a:hover{background:#edf5f2;border-color:#075744}
.learning-hint{font-size:14px;color:#56616d;margin-top:20px}
.skip-link{position:absolute;left:12px;top:-100px;background:#fff;color:#075744;padding:10px;z-index:10000}
.skip-link:focus{top:12px}
/* Existing note/quiz structure and saved progress remain intact. */
body:not(.learning-index){padding-bottom:110px}
.header-title{font-size:clamp(26px,5vw,34px);font-weight:700;line-height:1.4;letter-spacing:-.5px}
.title-hl{background:transparent;color:#20262e;padding:0}
.header-script,.header-sub,.header-tip,.sec-title,.toc-item,.toc-title,.exam,.note,.source{font-family:inherit}
.header-script{font-size:16px;color:#56616d;font-weight:400}
.header-sub{font-size:15px;text-decoration:none}
.header-divider{border:0;border-top:1px solid #d7dbdf}
.sec{border:1px solid #d7dbdf;border-radius:7px;box-shadow:none}
.sec-header{background:#f6f8f7;border-color:#d7dbdf}
.sec-title{font-size:18px;color:#20262e}
.sec-body{font-size:16px;line-height:1.8}
.note,.def,.exam p,.eg-note{font-size:16px;line-height:1.8}
.toc-item{font-size:14px;min-height:44px;display:inline-flex;align-items:center}
.learning-links{max-width:820px;margin:16px auto;display:flex;gap:8px;flex-wrap:wrap}
.tbl-wrap{overflow-x:auto}
@media(max-width:640px){
.site-header nav{padding:0 16px;display:block;min-height:0}
.site-header .site-brand{display:block;padding:15px 0;font-size:17px}
.subject-nav{justify-content:space-between;gap:12px}
.subject-nav a{min-height:48px;font-size:14px}
.learning-main{padding:26px 16px 36px}
.page-heading h1{font-size:30px}
.chapter-row{grid-template-columns:30px minmax(0,1fr);gap:8px 12px;padding:15px 0}
.chapter-number{font-size:20px;align-self:start}
.chapter-copy h2{font-size:17px}
.chapter-actions{grid-column:2;justify-self:start}
.chapter-actions a{padding:7px 15px}
.sec-header{padding:14px 12px;flex-wrap:wrap}
.sec-body{padding:16px 12px}
.sec-tag{margin-left:0}
}