/* A clear reading order: finding, mechanism, observation, optional source. */
#about-dialog #about-title{display:flex;align-items:center;gap:8px;flex-wrap:nowrap;white-space:nowrap}
#about-dialog #about-title .about-logo{margin:0;flex:none}
#about-dialog #about-title .about-name{display:inline;font:inherit;line-height:inherit;letter-spacing:inherit;color:inherit;white-space:nowrap}
#about-dialog #about-title .product-amp{display:inline;font-family:ui-serif,Georgia,serif;font-style:italic;font-size:1.1em;font-weight:400;line-height:inherit;color:inherit;margin:0}
@media(max-width:380px){#about-dialog #about-title{font-size:21px}#about-dialog #about-title .about-logo{width:28px;height:28px}}
.welcome-app-name .product-amp{font-size:1.1em}
[data-reference-change]{font-variant-numeric:tabular-nums;white-space:nowrap}
#about-dialog .about-heading{margin-bottom:17px}
#about-dialog .about-author{margin:22px 0 0}
#about-dialog .about-purpose{font-size:17px;line-height:1.6;font-weight:400;letter-spacing:-.012em;margin-top:0;color:var(--ink)}
#about-dialog .about-scope{font-size:12px;line-height:1.65;color:var(--soft);margin-top:18px}
#about-dialog .about-scope strong{font-weight:650;color:var(--ink)}
.sequence-heading{display:flex;align-items:baseline;gap:9px}
.sequence-heading .step-number{font-size:11px;font-weight:500;color:var(--soft);font-variant-numeric:tabular-nums}
.sequence-heading strong{font-size:14px;font-weight:600;line-height:1.45}
#causal-chain .sequence-numbers{font-size:12px!important;font-weight:500;color:var(--ink)}
.step-citations{font-size:10px;line-height:0;white-space:nowrap;margin-left:3px;vertical-align:super}
.study-marker{color:var(--venous-color);padding:3px;min-width:20px;min-height:24px;font-size:10px;line-height:1;font-weight:550;vertical-align:baseline;text-decoration:none;cursor:pointer}
.study-marker:hover,.study-marker:focus-visible{color:var(--ink)}
.lesson-references{margin:20px 0 12px;padding-top:12px;border-top:1px solid var(--line)}
.lesson-references>summary{font-size:12px;color:var(--soft);cursor:pointer}
.lesson-references ol{padding-left:22px;margin:12px 0 0}
.lesson-references li{font-size:11px!important;line-height:1.6;margin:0 0 10px;padding-left:3px}
.lesson-references a{text-decoration:none;color:var(--ink)}
.lesson-references small{display:block;color:var(--soft);font-size:10px;line-height:1.6}
.study-reference-hint{position:fixed;z-index:210;width:min(350px,calc(100vw - 24px));padding:14px 16px;background:var(--surface);color:var(--ink);border:1px solid var(--line);border-radius:10px;box-shadow:0 8px 28px #243c461c;font-size:12px;line-height:1.5;text-align:left}
.study-reference-hint[hidden]{display:none}
.study-reference-hint>strong{display:block;font-size:13px;line-height:1.45;font-weight:600}
.study-reference-hint p{margin:7px 0 0;font-size:12px}
.study-reference-hint>p:first-of-type{font-size:11px;color:var(--soft)}
.study-reference-hint>small{display:block;font-size:11px;color:var(--soft);line-height:1.5;margin-top:8px}
.study-reference-hint>a{display:inline-block;margin-top:10px;font-size:11px;color:var(--venous-color);text-decoration:none}
@media(max-width:480px){#about-dialog .about-purpose{font-size:16px;line-height:1.55}.study-marker{min-height:28px;min-width:24px}}

/* One illustrated idea at a time, with the complete science kept beside it. */
#school-depth{margin-top:16px}
#school-depth>.physiology-aspect{padding:0;border:0;border-top:1px solid var(--line);border-radius:0;background:none}
#school-depth>.physiology-aspect>summary{font-size:14px;font-weight:500;line-height:1.5;padding:15px 2px;color:var(--ink)}
#school-depth>.physiology-aspect[open]>summary{color:var(--venous-color)}
.lesson-reader{padding:4px 0 16px;min-width:0;container-type:inline-size}
.lesson-reader .lesson-lead{font-size:16px!important;font-weight:550;line-height:1.55!important;letter-spacing:-.01em;color:var(--ink);margin:3px 0 20px!important;max-width:65ch}
.lesson-step-nav{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:8px;margin:0 0 18px}
.lesson-step-nav>button{display:flex;gap:8px;align-items:flex-start;min-height:48px;padding:9px 6px;border:0;border-bottom:2px solid var(--line);border-radius:0;font-size:12px;line-height:1.4;text-align:left;color:var(--soft)}
.lesson-step-nav>button>span:first-child{flex:none;font-size:11px;line-height:18px;font-variant-numeric:tabular-nums}
.lesson-step-nav>button[aria-current=step]{border-color:var(--venous-color);color:var(--ink);font-weight:600}
.lesson-frame{display:grid;grid-template-columns:minmax(280px,360px) minmax(0,1fr);gap:26px;align-items:center;min-height:180px}
.lesson-illustration{display:grid;place-items:center;min-width:0;padding:12px 0}
.lesson-reader .physiology-sketch{max-width:360px;overflow:visible}
.lesson-step-count{font-size:9px;letter-spacing:.1em;color:var(--soft);font-weight:500}
.lesson-reader .lesson-step-copy h3{font-size:17px;font-weight:550;line-height:1.4;letter-spacing:-.012em;margin:5px 0 9px}
.lesson-reader .lesson-step-text{font-size:14px!important;line-height:1.65!important;color:var(--ink);margin:0!important}
.lesson-reader .lesson-equation{font-size:13px!important;line-height:1.6!important;color:var(--venous-color);font-weight:500;margin:14px 0 0!important;background:none;border:0;padding:0}
.lesson-reader details>summary{font-size:12px!important;font-weight:500;color:var(--soft);padding:10px 0!important;cursor:pointer;line-height:1.5}
.lesson-reader details[open]>summary{color:var(--ink)}
.lesson-reader details p{font-size:14px!important;line-height:1.7!important;color:var(--ink);margin:0 0 14px!important;max-width:75ch}
.lesson-reader .lesson-step-depth{margin:8px 0 0;border:0;padding:0}
.lesson-reader .lesson-step-depth[open]{padding-bottom:3px}
.lesson-pagination{display:flex;align-items:center;justify-content:space-between;gap:10px;margin:8px 0 17px}
.lesson-pagination button{min-height:42px;padding:8px 13px;border:1px solid var(--line);border-radius:7px;font-size:12px;font-weight:500}
.lesson-pagination button:disabled{visibility:hidden}
.lesson-pagination button[data-lesson-next]{background:var(--venous-faint);border-color:transparent;color:var(--ink)}
.lesson-pagination>span{font-size:11px;color:var(--soft);font-variant-numeric:tabular-nums}
.lesson-extras{border-top:1px solid var(--line);padding-top:5px}
.lesson-extras>.lesson-references{margin:0;padding:0;border:0}
.lesson-reader .lesson-live-example{border-left:2px solid var(--venous-color);padding:0 0 0 12px;font-size:13px!important;font-variant-numeric:tabular-nums}
.lesson-reader [data-pitfall]{color:var(--arterial-color)}
.lesson-reader .lesson-references li{font-size:12px!important;line-height:1.65}
.lesson-reader .lesson-references small{font-size:11px;line-height:1.6}
#lesson-library .school-heading{align-items:end;gap:15px;margin-bottom:22px}
#lesson-library .school-heading>label{display:grid;gap:7px;font-size:11px;color:var(--soft);flex:1}
#lesson-library .school-heading select{font-size:13px;color:var(--ink);width:100%}
#lesson-library #try-in-explore{font-size:11px;padding:10px 0;white-space:nowrap}
@media(max-width:650px){
 .lesson-frame{grid-template-columns:1fr;gap:8px;min-height:0}
 .lesson-illustration{padding:6px 0 10px}
 .lesson-step-copy{padding:0 2px}
 .lesson-step-nav{gap:5px}
 .lesson-step-nav>button{gap:5px;font-size:11px;padding:9px 2px;min-height:54px}
 .lesson-reader .lesson-lead{font-size:15px!important;margin-bottom:15px!important}
 .lesson-reader .lesson-step-copy h3{font-size:17px}
 .lesson-reader .lesson-illustration svg{max-width:360px}
 #lesson-library .school-heading{flex-wrap:wrap;gap:5px}
 #lesson-library .school-heading>label{flex-basis:100%}
}

/* Stack to protect diagram labels when the study panel itself is narrow. */
@container(max-width:650px){.lesson-frame{grid-template-columns:1fr;gap:10px;min-height:0}.lesson-illustration{padding:6px 0 12px}}

/* Keep the About paragraphs and author details visibly separate. */
#about-dialog p.about-purpose{margin:0 0 18px}
#about-dialog .about-author{margin-top:26px}
#about-dialog .about-author p:first-child{margin-bottom:0}
#about-dialog .about-author p+p{margin-top:0}