.study-nav{display:flex;gap:22px;font-size:13px;align-items:center}.study-nav a{text-decoration:none;color:#3c5b53}.course-introduction{max-width:1020px;margin:0 auto;padding:15px 30px;border-bottom:1px solid var(--line);font-size:12px;color:var(--muted);line-height:1.7}.course-introduction p{margin:4px 0}.course-introduction details{margin-top:8px}.course-introduction summary{cursor:pointer}.course-introduction .record-note{color:#624e2c}.course-image img{display:block;max-width:100%;width:100%;height:auto;object-fit:contain;max-height:720px;background:#fff}.course-image img[hidden]{display:none}.course-image figcaption{font-size:13px;color:var(--muted);margin-top:14px;line-height:1.8}.image-states{display:flex;gap:10px;margin:16px 0}.image-states [aria-pressed=true]{background:var(--teal);color:white}.lesson-connection{font-size:13px;color:var(--muted);margin:0 0 20px}.block-list{padding-left:24px;line-height:1.9}.block-list li{padding:5px 0}.worked-example{background:#f1f5f6;border-left:3px solid #7997a0;padding:18px 22px;margin:24px 0}.worked-example h3{margin:0 0 10px}.worked-example p:last-child,.caution p:last-child{margin-bottom:0}table caption{text-align:left;font-weight:700;color:var(--teal);font-size:15px;padding:8px 0}.concept-return{background:#fff;border:1px solid #d9e3df;border-radius:5px;margin:10px 0;padding:0 14px}.concept-return summary{padding:10px 0;cursor:pointer;color:#27564b;font-size:13px}.concept-return .embedded-section{margin:18px 0;font-size:15px}.concept-return .embedded-section h2{font-size:19px}.concept-return .secondary{margin:12px 0 18px}.reason p{white-space:pre-line}.question-title{white-space:pre-line}.question-context{font-size:13px;color:var(--muted);border-left:2px solid #a9bbb3;padding-left:15px}.lesson-actions,.bottom-actions{display:flex;gap:10px;align-items:center;flex-wrap:wrap}.bottom-bar .bottom-actions{max-width:none}.bottom-bar>div:first-child{min-width:0}.bottom-bar .primary,.bottom-bar .secondary{min-height:43px}.bottom-bar[hidden]{display:none}.feedback>strong{display:block;margin-bottom:14px}.feedback .reason{padding:14px 0}.feedback .reason>p{margin:8px 0 12px}.question .visual img{max-height:550px}.embedded-section .visual{margin:15px 0;padding:12px}.study-ad{display:none}.reader-footer{margin-top:30px}
@media(min-width:1450px){.study-ad{display:block;position:fixed;top:170px;width:140px;min-height:600px;pointer-events:none}.study-ad-left{right:calc(50% + 550px)}.study-ad-right{left:calc(50% + 550px)}}
@media(max-width:680px){.site-header{flex-wrap:wrap;gap:15px}.study-nav{gap:16px;font-size:12px}.course-introduction{padding:12px 20px}.course-introduction #course-notice{font-size:12px}.bottom-bar{align-items:center;gap:8px}.bottom-bar>div:first-child{display:none}.bottom-bar .bottom-actions{width:100%;justify-content:space-between;gap:6px}.bottom-bar .secondary{font-size:12px;padding:9px 10px}.bottom-bar .primary{font-size:12px;padding:9px 14px}.concept-return{padding:0 10px}.concept-return .embedded-section{font-size:14px}.worked-example{padding:16px}.lesson-actions{width:100%;justify-content:space-between}.course-image{padding:12px 8px}main{padding-bottom:125px}.brand span{font-size:12px}h1{overflow-wrap:anywhere}.lesson-copy{overflow-wrap:anywhere}.source-box a{overflow-wrap:anywhere}}
.reader-skip{position:absolute;left:20px;top:-60px;z-index:20;background:white;color:#163d45;padding:10px 16px}.reader-skip:focus{top:8px}
#outline summary{padding-bottom:12px}#lesson-list{top:100%}