:root{--yh-paper:#faf6ee;--yh-paper-deep:#f1e9da;--yh-ink:#3b2a20;--yh-ink-soft:#6b5a4e;--yh-red:#9e2a2b;--yh-red-dark:#7a1f20;--yh-jade:#2f6b4f;--yh-gold:#b8892e;--yh-line:#e3d8c6}html{scroll-behavior:smooth}@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}}body{background:var(--yh-paper);color:var(--yh-ink);font-family:Be Vietnam Pro,system-ui,sans-serif}.font-serif,h1,h2,h3{font-family:Noto Serif,Georgia,serif}a{color:var(--yh-jade)}a:hover{color:var(--yh-red)}.btn.btn-yh{background:var(--yh-red);color:#fff;border:1px solid var(--yh-red);border-radius:999px;padding:10px 22px;font-weight:600}.btn.btn-yh:hover,.btn.btn-yh:focus-visible{background:var(--yh-red-dark);border-color:var(--yh-red-dark);color:#fff}.btn.btn-yh:disabled{background:var(--yh-red);color:#fff;opacity:.6}.btn.btn-yh-outline{border:1px solid var(--yh-red);color:var(--yh-red);background:0 0;border-radius:999px;padding:9px 20px;font-weight:600}.btn.btn-yh-outline:hover{background:var(--yh-red);color:#fff}.site-header{z-index:100;-webkit-backdrop-filter:blur(6px);backdrop-filter:blur(6px);border-bottom:1px solid var(--yh-line);background:#faf6eef2;position:sticky;top:0}.site-header .inner{justify-content:space-between;align-items:center;gap:16px;min-height:64px;display:flex}.site-brand{color:var(--yh-ink);align-items:center;gap:10px;text-decoration:none;display:flex}.site-brand .seal{background:var(--yh-red);color:#fff;border-radius:8px;justify-content:center;align-items:center;width:38px;height:38px;font-family:Noto Serif,serif;font-weight:700;display:flex}.site-brand strong{font-family:Noto Serif,serif;font-size:1.05rem;line-height:1.1;display:block}.site-brand small{color:var(--yh-ink-soft);font-size:.75rem}.site-nav{align-items:center;gap:22px;display:flex}.site-nav a{color:var(--yh-ink);font-weight:500;text-decoration:none}.site-nav a.active,.site-nav a:hover{color:var(--yh-red)}.site-nav-toggle{color:var(--yh-ink);background:0 0;border:0;font-size:1.4rem;display:none}@media (max-width:767.98px){.site-nav-toggle{display:block}.site-nav{background:var(--yh-paper);border-bottom:1px solid var(--yh-line);flex-direction:column;gap:12px;padding:12px 16px 18px;display:none;position:absolute;top:64px;left:0;right:0}.site-nav.open{display:flex}}.site-footer{border-top:1px solid var(--yh-line);background:var(--yh-paper-deep);color:var(--yh-ink-soft);font-size:.9rem}.footer-login-link{color:var(--yh-ink-soft);text-underline-offset:3px;text-decoration:underline}.footer-login-link:hover{color:var(--yh-red)}.account-menu{position:relative}.account-menu-toggle{color:var(--yh-ink);border:1px solid var(--yh-line);background:0 0;border-radius:999px;align-items:center;gap:8px;padding:6px 14px;font-weight:500;display:inline-flex}.account-menu-toggle:hover{border-color:var(--yh-red);color:var(--yh-red)}.account-menu-list{z-index:1050;border:1px solid var(--yh-line);background:#fff;border-radius:12px;min-width:220px;padding:6px;position:absolute;top:calc(100% + 8px);right:0;box-shadow:0 12px 28px #3b2a201f}.account-menu-role{color:var(--yh-ink-soft);padding:6px 10px;font-size:.75rem}.account-menu-list a,.account-menu-list button{text-align:left;width:100%;color:var(--yh-ink);background:0 0;border:0;border-radius:8px;padding:8px 10px;font-weight:500;text-decoration:none;display:block}.account-menu-list a:hover,.account-menu-list button:hover{background:var(--yh-paper);color:var(--yh-red)}@media (max-width:767.98px){.account-menu-list{box-shadow:none;margin-top:8px;position:static}}.hero{background:radial-gradient(circle at 85% 20%,#9e2a2b1f,#0000 45%),radial-gradient(circle at 10% 90%,#2f6b4f1f,#0000 40%);padding:72px 0 56px}.hero h1{font-size:clamp(1.9rem,4vw,2.9rem);font-weight:700;line-height:1.2}.hero .lead{color:var(--yh-ink-soft);max-width:640px}.eyebrow{text-transform:uppercase;letter-spacing:.12em;color:var(--yh-red);font-size:.75rem;font-weight:700}.subject-card{border:1px solid var(--yh-line);height:100%;color:var(--yh-ink);background:#fff;border-radius:14px;flex-direction:column;text-decoration:none;transition:transform .2s,box-shadow .2s;display:flex;overflow:hidden}.subject-card:hover{color:var(--yh-ink);transform:translateY(-3px);box-shadow:0 12px 28px #3b2a201f}.subject-card-media{aspect-ratio:16/9;background:var(--yh-paper-deep);justify-content:center;align-items:center;display:flex}.subject-card-media img{object-fit:cover;width:100%;height:100%}.subject-card-media i{color:var(--yh-gold);font-size:2rem}.subject-card-body{flex-direction:column;flex:1;padding:18px 20px;display:flex}.subject-card-body h2{margin-bottom:8px;font-size:1.1rem;font-weight:700}.subject-card-body p{color:var(--yh-ink-soft);flex:1;font-size:.9rem}.subject-card-meta{color:var(--yh-jade);font-size:.8rem;font-weight:600}.breadcrumb-yh{color:var(--yh-ink-soft);font-size:.85rem}.breadcrumb-yh a{color:var(--yh-ink-soft);text-decoration:none}.breadcrumb-yh a:hover{color:var(--yh-red)}.outline{border:1px solid var(--yh-line);background:#fff;border-radius:14px}.outline-section+.outline-section{border-top:1px solid var(--yh-line)}.outline-section h2{color:var(--yh-red);margin:0;padding:16px 20px 6px;font-size:1rem;font-weight:700}.outline-list{counter-reset:lesson;margin:0;padding:0 8px 12px;list-style:none}.outline-list a{color:var(--yh-ink);border-radius:8px;padding:10px 12px;text-decoration:none;display:block}.outline-list a:hover{background:var(--yh-paper)}.outline-list .t{font-weight:600}.outline-list .t:before{counter-increment:lesson;content:counter(lesson) ". ";color:var(--yh-gold)}.outline-list .e{color:var(--yh-ink-soft);margin-top:2px;font-size:.85rem;display:block}.lesson-article{max-width:780px}.lesson-content{font-size:1.05rem;line-height:1.85}.lesson-content h2{color:var(--yh-red-dark);margin:32px 0 12px;scroll-margin-top:90px;font-size:1.4rem;font-weight:700}.lesson-content h3{margin:24px 0 10px;scroll-margin-top:90px;font-size:1.15rem;font-weight:700}.lesson-content p{margin-bottom:16px}.lesson-content ul,.lesson-content ol{margin-bottom:16px;padding-left:24px}.lesson-content li{margin-bottom:6px}.lesson-content img{border-radius:10px;max-width:100%;height:auto;margin:16px 0}.lesson-content blockquote{border-left:4px solid var(--yh-gold);background:var(--yh-paper-deep);border-radius:0 8px 8px 0;margin:20px 0;padding:12px 18px;font-style:italic}.lesson-content table{border-collapse:collapse;width:100%;margin-bottom:16px}.lesson-content th,.lesson-content td{border:1px solid var(--yh-line);padding:8px 10px}.lesson-content tr:first-child td{background:var(--yh-paper-deep);font-weight:600}.lesson-content .table-scroll{margin-bottom:16px;overflow-x:auto}.lesson-content .table-scroll table{min-width:480px;margin-bottom:0}.lesson-byline{color:var(--yh-ink-soft);font-size:.85rem}.lesson-download{flex-wrap:wrap;gap:8px;margin:4px 0 8px;display:flex}.lesson-download .btn{padding:6px 16px;font-size:.85rem}.lesson-quiz{border:1px solid var(--yh-line);background:#fff;border-radius:14px;margin-top:40px;padding:22px 20px}.lesson-quiz h2{color:var(--yh-red-dark);margin-bottom:4px;font-size:1.35rem;font-weight:700}.lesson-quiz-intro{color:var(--yh-ink-soft);font-size:.9rem}.quiz-list{margin:0;padding-left:1.4rem}.quiz-list>li{border-top:1px dashed var(--yh-line);padding:14px 0}.quiz-list>li::marker{font-weight:700}.quiz-question{white-space:pre-line;margin-bottom:8px;font-weight:600}.quiz-options{gap:6px;display:grid}.quiz-option{cursor:pointer;border:1px solid var(--yh-line);background:var(--yh-paper);border-radius:10px;align-items:flex-start;gap:10px;padding:8px 12px;display:flex}.quiz-option input{opacity:0;pointer-events:none;position:absolute}.quiz-option:hover{border-color:var(--yh-jade)}.quiz-option:has(input:focus-visible){outline:2px solid var(--yh-jade);outline-offset:1px}.quiz-option.chosen{border-color:var(--yh-jade);background:#e3f1ea}.quiz-option.right{border-color:var(--yh-jade);color:var(--yh-jade);background:#dcefe4;font-weight:600}.quiz-option.wrong{border-color:var(--yh-red);color:var(--yh-red-dark);background:#fbe7e6}.quiz-option:has(input:disabled){cursor:default}.quiz-letter{border:1px solid var(--yh-line);background:#fff;border-radius:50%;flex:none;justify-content:center;align-items:center;width:24px;height:24px;font-size:.8rem;font-weight:700;display:inline-flex}.quiz-feedback{border-left:3px solid var(--yh-gold);background:var(--yh-paper);white-space:pre-line;margin-top:8px;padding:8px 12px;font-size:.9rem}.is-correct .quiz-feedback{border-left-color:var(--yh-jade)}.is-wrong .quiz-feedback{border-left-color:var(--yh-red)}.quiz-score{background:#fbf1dc;border-radius:10px;margin-bottom:8px;padding:10px 14px}.quiz-score.full{background:#dcefe4}.quiz-actions{justify-content:flex-end;align-items:center;gap:12px;margin-top:12px;display:flex}.lesson-toc{border:1px solid var(--yh-line);background:#fff;border-radius:12px;margin:24px 0}.lesson-toc-head{width:100%;color:var(--yh-ink);background:0 0;border:0;justify-content:space-between;align-items:center;padding:12px 16px;font-weight:700;display:flex}.lesson-toc ol{margin:0;padding:0 12px 12px;list-style:none}.lesson-toc li a{color:var(--yh-ink-soft);border-left:2px solid #0000;padding:5px 10px;font-size:.92rem;text-decoration:none;display:block}.lesson-toc li.lv3 a{padding-left:26px;font-size:.86rem}.lesson-toc li.active a{border-left-color:var(--yh-red);color:var(--yh-red);font-weight:600}.lesson-pager{grid-template-columns:1fr 1fr;gap:12px;margin-top:40px;display:grid}.lesson-pager a{border:1px solid var(--yh-line);color:var(--yh-ink);background:#fff;border-radius:12px;padding:14px 16px;text-decoration:none;display:block}.lesson-pager a:hover{border-color:var(--yh-red)}.lesson-pager small{color:var(--yh-ink-soft);text-transform:uppercase;letter-spacing:.08em;font-size:.75rem;display:block}.lesson-pager .next{text-align:right;grid-column:2}@media (max-width:575.98px){.lesson-pager{grid-template-columns:1fr}.lesson-pager .next{grid-column:1}}.state-msg{text-align:center;color:var(--yh-ink-soft);padding:48px 0}