:root{font-family:system-ui,sans-serif;color:#17333b;background:#edf4fa;line-height:1.5}*{box-sizing:border-box}body{margin:0}[hidden]{display:none!important}main{max-width:1280px;margin:auto;padding:24px}header,.study-top{display:flex;align-items:center;justify-content:space-between;gap:18px;flex-wrap:wrap}h1{margin:0;font-size:clamp(1.8rem,4vw,2.6rem)}.eyebrow{font-weight:750;font-size:.9rem;letter-spacing:.055em;color:#52676e;margin:0 0 8px}.intro{margin:18px 0}button,.button{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:44px;padding:9px 14px;border:1px solid #8aa9a1;border-radius:9px;box-shadow:0 2px 0 #a7bcb5;background:white;color:#17333b;font:inherit;font-weight:650;cursor:pointer;text-decoration:none}button:hover,.button:hover{background:#f7f2e5}button:disabled{opacity:.5;cursor:default}button[aria-pressed=true],.primary{background:#176b61;color:white;border-bottom:3px solid #d8c595}nav,.controls{display:flex;gap:10px;flex-wrap:wrap;align-items:center}nav{margin:20px 0;padding:12px;border:1px solid #d4ded8;border-radius:12px;background:#ffffff99}button:focus-visible,a:focus-visible{outline:3px solid #176b61;outline-offset:3px}.diagram-layout{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:24px;align-items:start}#diagram{position:relative;width:100%;max-width:580px;margin:auto;background:white;border:1px solid #d4ded8;border-radius:12px;overflow:hidden}#diagram img{display:block;width:100%;height:auto}#markers{position:absolute;inset:0}.marker{position:absolute;transform:translate(-50%,-50%);min-height:32px;width:32px;padding:0;border-radius:50%;background:white;border:2px solid #17333b;box-shadow:0 1px 4px #17333b55;font-size:14px;z-index:1}.marker[aria-pressed=true]{background:#176b61;color:white;border:3px solid #d8c595;z-index:2}#organ-list{display:flex;gap:8px;flex-wrap:wrap}#organ-list button{font-size:1rem}.panel{padding:24px;background:white;border:1px solid #d4ded8;border-top:2px solid #d8c595;border-radius:12px;margin:20px 0}#organ-title{font-size:clamp(1.5rem,3vw,2.3rem);margin:8px 0}#organ-detail h3{font-size:1.05rem;margin:18px 0 5px}#organ-detail p{font-size:1.2rem;margin:0}.note{font-size:.95rem;color:#52676e}.pathway .controls{margin:16px 0}.pathway button[aria-current=step]{background:#176b61;color:white}#study-view{position:fixed;inset:0;z-index:1000;background:#f5f8f7;padding:clamp(18px,3vw,38px);overflow:auto;display:flex;flex-direction:column;gap:22px}body.studying{overflow:hidden}.study-top h2{margin:0;font-size:1.5rem}#study-content{flex:1}#study-content h3{font-size:clamp(1.6rem,3vw,3rem);line-height:1.3}.options{display:grid;gap:14px}.options button{text-align:left;justify-content:space-between;white-space:normal;padding:20px;font-size:clamp(1.2rem,2vw,2rem)}.options button:disabled{opacity:1}.correct{background:#e1f2df!important;border:2px solid #18733b!important}.incorrect{background:#fff0f2!important;border:2px solid #b42335!important}.symbol{font-size:52px;font-weight:800}.correct .symbol{color:#18733b}.incorrect .symbol{color:#b42335}.feedback{padding:18px;background:white;margin-top:18px;font-size:clamp(1.2rem,2vw,1.7rem)}.flash{display:flex;flex-direction:column;justify-content:center;align-items:center;width:100%;min-height:55vh;white-space:normal;padding:32px;background:#fff1ce}.flash.revealed{background:#e1f2df}.flash strong{font-size:clamp(2rem,4vw,4rem)}.flash span{font-weight:400;font-size:clamp(1.4rem,2.6vw,2.7rem);max-width:1000px}.flash .symbol{align-self:flex-end;color:#18733b}#study-view>.controls{justify-content:center}#sources{margin:24px 0}summary{cursor:pointer;font-weight:650}@media(max-width:750px){main{padding:16px}.diagram-layout{grid-template-columns:1fr}#diagram{max-width:440px}.marker{width:28px;min-height:28px;font-size:13px}.panel{padding:18px}#study-view{gap:16px}.options button{padding:15px}}
body.presenting main{max-width:none;padding:18px}body.presenting header,body.presenting .intro,body.presenting #sources,body.presenting .note{display:none}body.presenting #diagram{max-width:580px}body.presenting #organ-detail p{font-size:clamp(1.3rem,2vw,2rem)}body.presenting #organ-title{font-size:clamp(1.7rem,3vw,3rem)}

body.presenting #diagram-view .pathway{margin-top:18px}body.presenting .diagram-layout{align-items:start}
#organ-highlight{position:absolute;transform:translate(-50%,-50%);border:3px solid #b3924e;border-radius:50%;background:#e5c36b22;box-shadow:0 0 0 4px #fff8;pointer-events:none}#organ-info>button{margin:10px 8px 14px 0}#label-choice{display:block;width:100%;font:inherit;font-size:1.15rem;padding:12px;border:1px solid #8aa9a1;border-radius:9px;background:white;color:#17333b;margin:10px 0 14px}#organ-detail label{font-weight:650;display:block}#organ-detail .label-feedback{margin:18px 0;padding:16px;border-radius:10px;font-size:1.2rem;font-weight:650}#organ-detail .label-feedback:first-letter{font-size:2.3rem}#organ-detail>button{margin:8px 8px 8px 0}#closeup-dialog{width:min(640px,calc(100% - 24px));max-height:calc(100dvh - 24px);overflow:auto;padding:24px;border:1px solid #8aa9a1;border-top:3px solid #d8c595;border-radius:12px;background:white;color:#17333b}#closeup-dialog::backdrop{background:#17333b88}#closeup-title{font-size:1.4rem;margin:0}.closeup-image{position:relative;width:100%;max-width:380px;margin:22px auto;background:white}.closeup-image img{display:block;width:100%;height:auto}.closeup-image .marker{background:#176b61;color:white;border:3px solid #d8c595;box-shadow:0 0 0 3px white}#closeup-caption{font-size:1.15rem}

.system-picker{display:flex;align-items:center;gap:14px;flex-wrap:wrap;margin:20px 0}.system-picker label{font-weight:700}.system-picker select{font:inherit;font-weight:650;color:#17333b;background:white;padding:12px 14px;border:1px solid #8aa9a1;border-radius:9px;max-width:100%;min-height:44px}#system-connections p{font-size:1.2rem}.closeup-image{overflow:hidden}.closeup-image img{position:absolute;max-width:none}#diagram-credit p{font-size:.95rem}body.presenting .system-picker{margin:8px 0}

.marker-leaders{position:absolute;inset:0;width:100%;height:100%;pointer-events:none}.marker-leaders line{stroke:#17333b;stroke-width:.5;vector-effect:non-scaling-stroke}

/* Compact system controls wrap naturally so every choice stays visible. */
main{max-width:1400px}
.system-picker{display:block;padding:10px 12px;border:1px solid #d4ded8;border-top:3px solid #c5a65b;border-radius:12px;background:#fffdf5;margin:14px 0}
.system-picker h2{font-size:1rem;line-height:1.3;margin:0 0 8px;color:#17333b}
#system-buttons{display:flex;flex-wrap:wrap;align-items:stretch;gap:5px}
#system-buttons button{min-height:36px;line-height:1.2;padding:7px 8px;white-space:nowrap;text-align:center;background:white;border:1px solid #97b3ac;box-shadow:0 2px 0 #c8d7d1;font-size:14px;gap:4px}
#system-buttons button[aria-pressed=true]{background:#176b61;color:white;border-color:#10534b;box-shadow:0 2px 0 #10534b}
#system-buttons button[aria-pressed=true]:before{content:'✓';font-weight:800;flex-shrink:0}
#system-buttons button:hover:not([aria-pressed=true]){background:#edf5f0}
.system-explanation{padding:0 0 16px;margin-bottom:16px;border-bottom:1px solid #d4ded8}
.system-explanation h3{font-size:1.05rem;margin:0 0 6px;color:#176b61}
.system-explanation p{font-size:1.1rem;margin:0;line-height:1.5}
@media(max-width:650px){.system-picker{padding:10px}#system-buttons{gap:6px}#system-buttons button{min-height:44px;padding:8px 10px;font-size:14px}}
/* Keep the system chooser label readable across appearance preferences. */
.system-picker h2{font-size:1.15rem;font-weight:750;margin-bottom:10px}
html[data-appearance="dark"] .system-picker{background:#202c38!important;border-color:#667789!important;border-top-color:#d6b873!important}
html[data-appearance="dark"] .system-picker h2{color:#f1f5f8!important}
html[data-appearance="dark"] #system-buttons button[aria-pressed="true"]{background:#375f51!important;color:#fff!important;border-color:#a8c7b8!important}
html[data-reading-contrast="high"] .system-picker{background:#fff!important;border-color:#000!important}
html[data-reading-contrast="high"] .system-picker h2{color:#000!important}
html[data-reading-contrast="high"][data-appearance="dark"] .system-picker{background:#000!important;border-color:#fff!important}
html[data-reading-contrast="high"][data-appearance="dark"] .system-picker h2{color:#fff!important}