/* Book context and a questioning mind, together on the cream canvas. */
.chapter-band--mastery>.mastery-section{position:relative;padding-block:80px 86px}
.mastery-anchor{position:absolute;top:0;left:0;width:1px;height:1px;pointer-events:none}
.mastery-heading{display:flex;justify-content:space-between;align-items:flex-end;gap:40px;margin-bottom:32px}
.mastery-heading .eyebrow{font-size:.75rem;line-height:1.6;letter-spacing:.12em;margin:0 0 15px}
.mastery-heading h2{margin:0;font-size:clamp(3rem,5.7vw,5.25rem);line-height:1.05;letter-spacing:-.065em;color:#101828}
.mastery-heading h2 span{color:#197DA7}
.mastery-heading>p{font-size:1.0625rem;line-height:1.7;color:#536274;max-width:440px;margin:0 0 3px}
.mastery-shell{display:grid;grid-template-columns:minmax(0,1.25fr) minmax(0,1fr);isolation:isolate;border:1px solid #10182812;border-radius:28px;background:#FFFFFF9E;box-shadow:inset 0 1px 0 #FFF,0 20px 50px -37px #25587655;overflow:hidden}
.mastery-book-side{min-width:0;padding:30px 30px 0}
.mastery-book-heading{display:flex;align-items:center;gap:25px;min-height:187px;margin-bottom:22px}
.mastery-cover{width:116px;flex:none;perspective:850px}
.mastery-cover img{display:block;width:100%;height:auto;border-radius:3px 6px 6px 3px;transform:rotate(-4deg) rotateY(-9deg);box-shadow:3px 2px 0 #DDD9C8,8px 15px 18px #10182822;transition:transform .5s cubic-bezier(.22,1,.36,1)}
.mastery-cover:hover img{transform:rotate(-1deg) rotateY(-3deg) translateY(-3px)}
.mastery-book-copy{min-width:0}
.mastery-subjects{display:flex;flex-wrap:wrap;gap:7px;margin-bottom:12px}
.mastery-subjects span{font-size:.75rem;line-height:1.4;padding:4px 9px;border-radius:999px;background:#DEF0F5;color:#286B87}
.mastery-subjects span+span{background:transparent;border:1px solid #D8DEE0;color:#61727D;padding:3px 9px}
.mastery-book-copy h3{font-size:2rem;line-height:1.15;letter-spacing:-.045em;margin:0}
.mastery-book-copy h3>span{display:block;font-size:1rem;line-height:1.45;font-weight:500;letter-spacing:-.015em;margin-top:5px}
.mastery-author{font-size:.9375rem;color:#41576B;margin:9px 0 5px}
.mastery-origin{font-size:.8125rem;color:#697885;margin:0;display:flex;gap:8px}
.mastery-formats{display:flex;gap:10px 14px;flex-wrap:wrap;margin-top:13px}
.mastery-formats span{display:flex;align-items:center;gap:5px;font-size:.75rem;color:#5B6F7E}
.mastery-formats .icon{width:15px;height:15px;color:#299AD8}
.mastery-tabs{display:flex;gap:16px;border-bottom:1px solid #DAE0DD;overflow-x:auto;scrollbar-width:thin;overscroll-behavior-x:contain}
.mastery-tabs button{position:relative;flex:none;padding:12px 0 14px;font-size:.875rem;line-height:1.4;background:transparent;color:#657586;border:0;white-space:nowrap}
.mastery-tabs button::after{content:'';position:absolute;left:0;right:0;bottom:0;height:2px;background:#299AD8;transform:scaleX(0);transition:transform .25s ease}
.mastery-tabs button[aria-selected=true]{color:#166F99;font-weight:600}
.mastery-tabs button[aria-selected=true]::after{transform:scaleX(1)}
.mastery-tabs button:focus-visible{outline:2px solid #1479AF;outline-offset:-2px;border-radius:4px}
.mastery-record{height:337px;padding-top:20px}
.mastery-panel{height:100%;overflow:auto;scrollbar-width:thin;padding:0 2px 13px;overscroll-behavior:contain}
.mastery-panel:focus-visible{outline:2px solid #1479AF;outline-offset:3px;border-radius:4px}
.mastery-panel h4{font-size:1.125rem;line-height:1.4;letter-spacing:-.025em;margin:0 0 12px}
.mastery-panel>p{font-size:.9375rem;line-height:1.65;margin:0 0 14px;color:#536274}
.mastery-panel-top{display:flex;align-items:baseline;justify-content:space-between;gap:12px}
.mastery-panel-top>span{font-size:.625rem;letter-spacing:.12em;color:#637C89;white-space:nowrap}
.mastery-original{display:flex;align-items:center;justify-content:space-between;gap:12px;background:#EDF4F1;padding:10px 12px;border-radius:8px;margin:12px 0 16px}
.mastery-original>span{font-size:.8125rem;color:#647A87;flex:none}
.mastery-original>bdi{font-family:Arial,sans-serif;font-size:1rem;color:#101828}
.mastery-panel h5{font-size:.8125rem;font-weight:600;margin:0 0 8px}
.mastery-related{list-style:none;padding:0;margin:0}
.mastery-related li{display:flex;justify-content:space-between;gap:10px;font-size:.8125rem;line-height:1.5;padding:7px 0;border-bottom:1px solid #1018280B}
.mastery-related li>span{font-size:.75rem;color:#687E8A}
.mastery-facts{margin:0 0 8px}
.mastery-facts>div{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:10px 9px;border-bottom:1px solid #1018280C;border-radius:6px;transition:background .35s,box-shadow .35s}
.mastery-facts dt{font-size:.875rem;line-height:1.4;color:#536274}
.mastery-facts dd{font-size:.8125rem;line-height:1.4;margin:0;color:#536274;text-align:right}
.mastery-facts dd strong{font-size:1.125rem;letter-spacing:-.025em;font-variant-numeric:tabular-nums;font-weight:600;color:#101828}
.mastery-fact-divider{color:#9EAEB4;margin:0 5px}
.mastery-panel .mastery-record-source{font-size:.75rem;line-height:1.5;color:#73818A;margin:8px 0 14px}
.mastery-influence{display:grid;grid-template-columns:auto 1fr;gap:7px 12px;align-items:center;padding:12px 13px;border:1px solid #DAE5E8;border-radius:10px;background:#F0F6F7;transition:box-shadow .35s}
.mastery-influence>span{font-size:.625rem;letter-spacing:.12em;color:#597583}
.mastery-influence>strong{font-size:.9375rem;text-align:right;font-weight:600;color:#52646E}
.mastery-influence>p{grid-column:1/-1;font-size:.8125rem;line-height:1.5;color:#627480;margin:0}
.mastery-panel .mastery-reference-status{font-size:.8125rem;background:#F4F2E9;color:#746C56;border-radius:7px;padding:9px 11px;line-height:1.5;margin-bottom:12px}
.mastery-reference-marks{margin:0 0 13px}
.mastery-reference-marks>div{display:flex;align-items:center;gap:12px;margin:0 0 8px;border-radius:7px;padding:3px;transition:background .35s,box-shadow .35s}
.mastery-reference-marks dt{padding:4px 9px;border-radius:999px;font-size:.75rem;font-weight:600;flex:none;min-width:83px;text-align:center}
.mastery-reference-marks dd{font-size:.8125rem;line-height:1.5;color:#536274;margin:0}
.mastery-found{background:#E9F6EF;color:#207448}.mastery-retracted{background:#FAEDEF;color:#A7334E}.mastery-notfound{background:#ECF0F3;color:#626F7E}
.mastery-panel .mastery-reference-context{font-size:.8125rem;line-height:1.55;margin:0;color:#536274}
.mastery-evidence-active{background:#DFF2F7!important;box-shadow:inset 3px 0 0 #299AD8}
.mastery-book-footer{display:flex;justify-content:space-between;align-items:center;gap:12px;border-top:1px solid #1018280D;padding:15px 0 18px}
.mastery-book-footer>span{font-size:.6875rem;line-height:1.5;color:#74838D;max-width:185px}
.mastery-book-footer>a{display:inline-flex;align-items:center;gap:6px;font-size:.75rem;line-height:1.4;color:#196F99;font-weight:600}
.mastery-book-footer .icon{width:16px;height:16px;flex:none}
.mastery-ai{display:flex;flex-direction:column;min-width:0;padding:30px 28px 22px;background:radial-gradient(ellipse at 100% 0,#A5DEF030,transparent 70%),#EDF5F6;border-left:1px solid #D6E4E7}
.mastery-ai-heading{display:flex;align-items:center;gap:12px;margin-bottom:23px}
.mastery-ai-symbol{display:grid;place-items:center;width:40px;height:40px;border-radius:13px;background:#FFF;color:#197DA7;box-shadow:0 2px 5px #10182806;flex:none}
.mastery-ai-symbol .icon{width:22px;height:22px}
.mastery-ai-heading h3{font-size:1.125rem;letter-spacing:-.03em;line-height:1.4;margin:0 0 3px}
.mastery-ai-heading p{font-size:.8125rem;line-height:1.45;color:#657986;margin:0}
.mastery-question-options{display:flex;flex-direction:column;gap:6px;margin-bottom:18px}
.mastery-question-options button{display:flex;justify-content:space-between;align-items:center;gap:10px;text-align:left;font-size:.875rem;line-height:1.5;padding:10px 12px;border:1px solid #CADFE6;background:#FFFFFF75;border-radius:9px;color:#365E73;transition:background .2s,border-color .2s}
.mastery-question-options button[aria-pressed=true]{border-color:#70B5D5;background:#FFF;color:#155F85}
.mastery-question-options button:hover{background:#FFF;border-color:#299AD8}
.mastery-question-options .icon{width:16px;height:16px;flex:none}
.mastery-conversation{height:256px;min-height:0;overflow-y:auto;overscroll-behavior:contain;scrollbar-width:thin;padding:2px 2px 8px;flex:1}
.mastery-turn+.mastery-turn{margin-top:20px}
.mastery-question-bubble{max-width:92%;margin:0 0 17px auto;padding:11px 14px;background:#D7EBF4;border:1px solid #CEE4EE;border-radius:12px 12px 2px 12px;font-size:.9375rem;line-height:1.55;color:#26495E}
.mastery-answer{padding:0 2px}
.mastery-answer>span{display:flex;align-items:baseline;gap:10px;font-size:.6875rem;font-weight:700;letter-spacing:.11em;color:#1A7FAE}
.mastery-answer>span small{font-size:.6875rem;font-weight:400;letter-spacing:0;color:#77919F}
.mastery-answer>p,.mastery-answer-result>p{font-size:.9375rem;line-height:1.65;color:#40596B;margin:10px 0 0}
.mastery-answer strong{font-weight:600;color:#182E42}
.mastery-typing{display:flex;align-items:center;gap:5px;height:40px;color:#298AB7}
.mastery-typing i{width:5px;height:5px;background:currentColor;border-radius:50%;animation:mastery-dot 1s ease-in-out infinite}
.mastery-typing i:nth-child(2){animation-delay:.12s}.mastery-typing i:nth-child(3){animation-delay:.24s}
.mastery-paused .mastery-typing i{animation-play-state:paused}
@keyframes mastery-dot{0%,65%,100%{opacity:.35;transform:translateY(0)}30%{opacity:1;transform:translateY(-3px)}}
.mastery-followup{display:flex;align-items:center;justify-content:space-between;gap:10px;text-align:left;min-height:44px;padding:11px 12px;border:1px solid #BFD9E3;background:#FFFFFFA1;color:#216887;font-size:.8125rem;line-height:1.5;border-radius:9px;margin-top:13px;flex:none}
.mastery-followup .icon{width:16px;height:16px;flex:none}
.mastery-followup:disabled{opacity:.6;cursor:default}
.mastery-sample-note{font-size:.6875rem;line-height:1.55;margin:11px 0 0;color:#748A95}
@media(min-width:1440px){.mastery-shell{grid-template-columns:minmax(0,1.35fr) minmax(0,1fr)}.mastery-book-side{padding-inline:36px}.mastery-ai{padding-inline:36px}.mastery-book-heading{gap:30px}.mastery-cover{width:125px}}
@media(max-width:1050px){.mastery-heading{gap:30px}.mastery-heading>p{max-width:380px;font-size:1rem}.mastery-book-side{padding:24px 20px 0}.mastery-ai{padding:24px 20px 20px}.mastery-cover{width:90px}.mastery-book-heading{gap:19px}.mastery-tabs{gap:12px}.mastery-tabs button{font-size:.8125rem}.mastery-facts>div{padding-inline:4px;gap:8px}.mastery-facts dt{font-size:.8125rem}.mastery-facts dd strong{font-size:1rem}}
@media(max-width:820px){
 .chapter-band--mastery>.mastery-section{padding-block:56px}
 .mastery-heading{display:block;margin-bottom:26px}.mastery-heading h2{font-size:3.5rem}.mastery-heading .eyebrow{font-size:.6875rem;margin-bottom:12px}.mastery-heading>p{max-width:590px;font-size:1rem;margin-top:18px;line-height:1.65}
 .mastery-shell{grid-template-columns:minmax(0,1fr);border-radius:21px}.mastery-book-side{padding:24px 24px 0}
 .mastery-book-heading{min-height:157px;margin-bottom:17px}.mastery-cover{width:95px}.mastery-book-copy h3{font-size:1.875rem}.mastery-book-copy h3>span{font-size:.9375rem}.mastery-record{height:310px;padding-top:17px}
 .mastery-tabs{gap:20px}.mastery-tabs button{font-size:.875rem}.mastery-panel-top>span{font-size:.625rem}.mastery-facts dt{font-size:.875rem}.mastery-facts dd strong{font-size:1.125rem}
 .mastery-ai{border-left:0;border-top:1px solid #D6E4E7;padding:22px 24px}.mastery-ai-heading{margin-bottom:17px}
 .mastery-conversation{flex:none;height:248px}.mastery-question-options{margin-bottom:17px;gap:6px}.mastery-followup{margin-top:9px}
}
@media(max-width:420px){.mastery-heading h2{font-size:3rem}.mastery-book-side{padding:20px 16px 0}.mastery-ai{padding:20px 16px}.mastery-cover{width:78px}.mastery-book-heading{gap:16px}.mastery-book-copy h3{font-size:1.625rem}.mastery-book-copy h3>span{font-size:.875rem}.mastery-subjects{gap:5px;margin-bottom:9px}.mastery-subjects span{font-size:.6875rem}.mastery-formats{gap:8px}.mastery-formats span{font-size:.6875rem}.mastery-tabs{gap:14px}.mastery-tabs button{font-size:.8125rem}.mastery-facts>div{align-items:flex-start}.mastery-facts dt{max-width:115px}.mastery-facts dd{max-width:155px}.mastery-original{flex-wrap:wrap}.mastery-book-footer{flex-wrap:wrap}.mastery-book-footer>span{max-width:none}.mastery-record{height:330px}}
@media(prefers-reduced-motion:reduce){.mastery-section *{animation:none!important;transition:none!important}.mastery-cover img{transform:none!important}}

/* Three real app records, one synchronized workspace. Screenshot assets remain intact;
   these viewports display only each supplied cover. */
.mastery-library{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px;margin:0 0 17px}
.mastery-library>button{display:flex;align-items:center;position:relative;min-width:0;gap:13px;padding:15px 33px 15px 15px;text-align:left;border:1px solid #10182815;border-radius:16px;background:#FFFFFF6B;transition:background .3s,border-color .3s,box-shadow .3s;color:#101828}
.mastery-library>button[aria-pressed=true]{background:#EFF8F8;border-color:#5DB1D8;box-shadow:0 5px 14px -12px #197DA7}
.mastery-library>button:hover{border-color:#299AD8;background:#F5FAF6}
.mastery-choice-copy{display:flex;flex-direction:column;gap:4px;min-width:0}
.mastery-choice-copy strong{font-size:.9375rem;line-height:1.35;letter-spacing:-.02em}
.mastery-choice-copy>span{font-size:.75rem;line-height:1.4;color:#627687}
.mastery-choice-copy small{font-size:.75rem;line-height:1.45;color:#227298;font-variant-numeric:tabular-nums}
.mastery-choice-check{width:16px;height:16px;position:absolute;right:12px;top:16px;color:#1479AF;opacity:0}
.mastery-library>button[aria-pressed=true] .mastery-choice-check{opacity:1}
.mastery-art{position:relative;overflow:hidden;aspect-ratio:2/3;flex:none;border-radius:4px;background:#FFF}
.mastery-art[data-cover=sapiens]{--crop-width:534.465%;--crop-x:0%;--crop-y:-16.867%;aspect-ratio:383/581}
.mastery-art[data-cover=idiots]{--crop-width:547.594%;--crop-x:-4.011%;--crop-y:-18.426%;aspect-ratio:374/559}
.mastery-art[data-cover=agreements]{--crop-width:556.522%;--crop-x:-13.044%;--crop-y:-5.797%;aspect-ratio:368/552}
.mastery-art img{position:absolute;display:block;max-width:none!important;width:var(--crop-width)!important;height:auto!important;left:var(--crop-x);top:var(--crop-y);transform:none!important;box-shadow:none!important;border-radius:0}
.mastery-mini-cover{width:38px;box-shadow:1px 2px 3px #1018281F}
.mastery-cover.mastery-art{transform:rotate(-3deg);box-shadow:3px 2px 0 #DDD9C8,8px 15px 18px #10182822;transition:transform .4s ease}
.mastery-cover.mastery-art:hover{transform:rotate(0) translateY(-2px)}
.mastery-book-copy h3>#mastery-book-title{font:inherit;line-height:inherit;letter-spacing:inherit;margin-top:0}
.mastery-book-heading{min-height:205px}
.mastery-original>bdi{overflow-wrap:anywhere;text-align:end;line-height:1.4}
.mastery-original>span{white-space:nowrap}
.mastery-missing-detail{display:block;font-size:.75rem;color:#6B8090;margin-top:3px}
.mastery-record{height:389px}
.mastery-influence meter{grid-column:1/-1;width:100%;height:6px;border:0;display:block;appearance:none;background:#DCE8EC;border-radius:999px;overflow:hidden}
.mastery-influence meter::-webkit-meter-bar{background:#DCE8EC;border:0;height:6px;border-radius:999px}
.mastery-influence meter::-webkit-meter-optimum-value{background:#299AD8;border-radius:999px}
.mastery-influence meter::-moz-meter-bar{background:#299AD8;border-radius:999px}
.mastery-reference-intro{margin-bottom:11px}
.mastery-reference-badge{display:inline-block;font-size:.625rem;font-weight:600;letter-spacing:.11em;color:#1F7AA3;line-height:1.5;margin-bottom:6px}
.mastery-reference-intro h4{font-size:1.125rem;line-height:1.3;letter-spacing:-.035em;margin:0 0 6px}
.mastery-reference-intro>p{font-size:.6875rem;line-height:1.45;color:#758895;margin:0}
.mastery-reference-route{display:flex;align-items:center;justify-content:space-between;gap:10px;border:1px solid #CDE2E9;border-radius:9px;padding:9px 12px;background:#EFF7F9;margin-bottom:10px}
.mastery-reference-route>span{font-size:.8125rem;font-weight:500;line-height:1.45;color:#3C6278}
.mastery-reference-route b{font-weight:400;color:#89ABB8;margin:0 4px}.mastery-reference-route .icon{width:18px;height:18px;color:#299AD8}
.mastery-reference-panel .mastery-reference-status{font-size:.6875rem;padding:6px 9px;margin-bottom:9px}
.mastery-reference-panel .mastery-reference-marks>div{margin-bottom:5px}
.mastery-reference-panel .mastery-reference-context{border-top:1px solid #DBE7E8;padding-top:10px;font-size:.75rem;line-height:1.5}
.mastery-reference-banner{grid-column:1/-1;display:flex;align-items:center;justify-content:space-between;gap:25px;border-top:1px solid #D5E4E6;padding:20px 30px;background:linear-gradient(110deg,#F2F8F5,#EDF6F6)}
.mastery-reference-banner .mastery-reference-badge{margin-bottom:4px}
.mastery-reference-banner h3{font-size:1.1875rem;line-height:1.3;letter-spacing:-.03em;margin:0 0 5px}
.mastery-reference-banner p{font-size:.8125rem;line-height:1.5;color:#617784;margin:0}
.mastery-reference-banner>button{display:flex;align-items:center;gap:9px;flex:none;background:#FFFFFFAE;border:1px solid #9DCADA;padding:11px 15px;border-radius:999px;color:#1B7094;font-size:.8125rem;line-height:1.5;transition:background .2s,border-color .2s}
.mastery-reference-banner>button:hover{background:#FFF;border-color:#299AD8}
.mastery-reference-banner .icon{width:16px;height:16px}
@media(max-width:1050px){.mastery-library{gap:9px}.mastery-library>button{padding:12px 26px 12px 12px;gap:10px}.mastery-choice-copy strong{font-size:.8125rem}.mastery-mini-cover{width:32px}.mastery-choice-check{right:8px;width:14px}.mastery-book-heading{min-height:222px}}
@media(max-width:820px){.mastery-library{display:flex;overflow-x:auto;overscroll-behavior-x:contain;scroll-snap-type:x proximity;scrollbar-width:thin;padding:1px 1px 8px;margin-bottom:10px}.mastery-library>button{flex:0 0 240px;scroll-snap-align:start;min-height:90px}.mastery-mini-cover{width:36px}.mastery-choice-copy strong{font-size:.875rem}.mastery-book-heading{min-height:193px}.mastery-record{height:375px}.mastery-reference-banner{padding:20px 24px;align-items:flex-start;flex-direction:column;gap:14px}}
@media(max-width:420px){.mastery-library>button{flex-basis:225px}.mastery-book-heading{min-height:206px}.mastery-record{height:395px}.mastery-reference-banner{padding:18px 16px}.mastery-reference-route{gap:7px;padding:8px}.mastery-reference-route>span{font-size:.75rem}.mastery-original{align-items:flex-start}.mastery-original>bdi{text-align:start}}
@media(prefers-reduced-motion:reduce){.mastery-cover.mastery-art{transform:none!important}}