/* Spotlight recomposed as ten chapters (2026-09-21): a chapter rail, a mobile chapter bar,
   and the same three-part shape in every chapter: primer, what to do, take away. */
.shell-grid{display:grid;grid-template-columns:minmax(0,1fr);gap:0;align-items:start}
.chapter-rail{display:none}
.chapter-rail ol{list-style:none;margin:0;padding:0}
.chapter-rail .rail-part{font:10px/1.6 var(--mono);letter-spacing:.14em;text-transform:uppercase;color:var(--muted);margin:18px 0 6px;padding-left:12px}
.chapter-rail .rail-part:first-child{margin-top:0}
.chapter-rail button{display:grid;grid-template-columns:26px minmax(0,1fr) 16px;align-items:center;gap:8px;width:100%;min-height:40px;padding:7px 8px 7px 12px;border:0;border-left:2px solid transparent;border-radius:0;background:transparent;text-align:left;font:13px/1.35 var(--sans,Arial,sans-serif);color:var(--text)}
.chapter-rail button .rail-n{font:11px/1 var(--mono);color:var(--muted)}
.chapter-rail button .rail-check{font:11px/1 var(--mono);color:var(--muted);opacity:0}
.chapter-rail button.visited .rail-check{opacity:1}
.chapter-rail button.optional strong{font-weight:400;font-style:italic}
.chapter-rail button:hover{background:var(--surface2)}
.chapter-rail button[aria-current=page]{border-left-color:var(--accent,#a52d34);background:var(--surface);font-weight:600}
.chapter-rail button[aria-current=page] .rail-n{color:var(--accent,#a52d34)}
.chapter-rail .rail-foot{margin:18px 0 0;padding:12px;border-top:1px solid var(--line);font-size:11px;line-height:1.6;color:var(--muted)}
.chapter-rail .rail-foot button{display:inline;width:auto;min-height:0;padding:0;border:0;font:inherit;color:var(--accent,#a52d34);text-decoration:underline}
.chapter-bar{position:sticky;top:0;z-index:30;display:flex;align-items:stretch;gap:0;margin:0 0 18px;border:1px solid var(--line);background:var(--surface)}
.chapter-bar button{border:0;border-radius:0;background:transparent;min-height:46px}
.chapter-bar .bar-step{flex:none;width:46px;font-size:18px}
.chapter-bar .bar-step+.bar-step{border-left:1px solid var(--line)}
.chapter-bar #chapter-contents{flex:1;min-width:0;overflow:hidden;display:flex;flex-direction:column;align-items:flex-start;justify-content:center;gap:2px;text-align:left;padding:6px 12px;border-left:1px solid var(--line);border-right:1px solid var(--line)}
.chapter-bar #chapter-contents small{font:10px/1.4 var(--mono);letter-spacing:.1em;text-transform:uppercase;color:var(--muted)}
.chapter-bar #chapter-contents strong{font-size:14px;line-height:1.3;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;max-width:100%;display:block;width:100%}.chapter-bar #chapter-title{display:block;min-width:0;max-width:100%}
.shell-grid[data-contents=open] .chapter-rail{display:block;position:fixed;inset:0 0 0 auto;width:min(360px,100vw);z-index:40;overflow:auto;padding:16px 14px;background:var(--surface);border-left:1px solid var(--line);box-shadow:-10px 0 30px #0004}
.shell-grid[data-contents=open] .chapter-rail .rail-close{display:block;width:100%;margin-bottom:8px;min-height:40px;border:1px solid var(--line)}
.chapter-rail .rail-close{display:none}
@media(min-width:1200px){
 .shell-grid{grid-template-columns:232px minmax(0,1fr);gap:36px}
 .chapter-rail{display:block;position:sticky;top:18px;padding:6px 0 0;border-right:1px solid var(--line);max-height:calc(100vh - 36px);overflow:auto}
 .chapter-bar{display:none}
 .shell-grid[data-contents=open] .chapter-rail{position:sticky;inset:auto;width:auto;box-shadow:none;border-left:0;padding:6px 0 0}
 .shell-grid[data-contents=open] .chapter-rail .rail-close{display:none}
}
/* Chapter shell */
.chapter[hidden]{display:none}
.chapter-head{margin:0 0 22px;max-width:76ch}
.chapter-head .eyebrow{margin-bottom:10px}
.chapter-head h2{font:400 clamp(30px,4vw,44px)/1.08 var(--serif);letter-spacing:-.03em;margin:0 0 12px}
.chapter-head .lead{font-size:16px;line-height:1.6;margin:0;color:var(--text)}
.chapter-head .optional-tag{display:inline-block;font:10px/1.5 var(--mono);letter-spacing:.1em;text-transform:uppercase;border:1px solid var(--line);padding:4px 8px;margin-left:8px;vertical-align:middle;color:var(--muted)}
.primer{border:1px solid var(--line);border-top:3px solid var(--accent,#a52d34);background:var(--surface);padding:20px 24px 18px;margin:0 0 18px;max-width:86ch}
.primer-label{font:10px/1.7 var(--mono);letter-spacing:.14em;text-transform:uppercase;color:var(--muted);margin:0 0 10px}
.primer-label a{color:inherit}
.primer p{font-size:14.5px;line-height:1.65;margin:0 0 10px}
.primer p:last-child{margin-bottom:0}
.formula{display:flex;flex-wrap:wrap;align-items:baseline;gap:6px 16px;padding:12px 16px;margin:12px 0;background:var(--surface2);border-left:2px solid var(--text)}
.formula code{font:15px/1.5 var(--mono);white-space:normal;overflow-wrap:anywhere}
.formula span{font:10px/1.5 var(--mono);letter-spacing:.08em;text-transform:uppercase;color:var(--muted)}
.formula-key{margin:-4px 0 12px;font-size:12.5px;line-height:1.6;color:var(--muted)}.formula-key b{font-family:var(--mono);color:var(--text)}
.primer-steps{margin:12px 0 0;padding:0;list-style:none;counter-reset:step;display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px 22px}
.primer-steps li{counter-increment:step;position:relative;padding:0 0 0 32px;font-size:13px;line-height:1.55}
.primer-steps li::before{content:counter(step);position:absolute;left:0;top:1px;width:22px;height:22px;border:1px solid var(--text);border-radius:50%;font:11px/22px var(--mono);text-align:center}
.primer-steps b{display:block;font-weight:600;margin-bottom:2px}
.todo{display:grid;grid-template-columns:auto minmax(0,1fr);gap:6px 18px;align-items:start;padding:14px 18px;margin:0 0 20px;border:1px solid var(--accent,#a52d34);background:var(--accent-soft,#a52d3412);max-width:86ch}
.todo>span{font:10px/1.7 var(--mono);letter-spacing:.14em;text-transform:uppercase;color:var(--accent,#a52d34);padding-top:3px;white-space:nowrap}
.todo ol{margin:0;padding-left:20px;font-size:14px;line-height:1.6}
.todo li{margin:3px 0}
.todo b{font-weight:600;font-family:var(--mono);font-size:12px;padding:1px 7px;border:1px solid currentColor;border-radius:4px;white-space:nowrap}
.deeper{margin:22px 0 0;border:1px solid var(--line);background:var(--surface)}
.deeper>summary{padding:14px 18px;font:600 13px/1.4 var(--sans,Arial,sans-serif);color:var(--accent,#a52d34);list-style:none;cursor:pointer}
.deeper>summary::before{content:"+ ";font-family:var(--mono)}
.deeper[open]>summary::before{content:"− "}
.deeper>summary::-webkit-details-marker{display:none}
.deeper>*:not(summary){margin-left:18px;margin-right:18px}
.deeper>*:last-child{margin-bottom:18px}
.deeper .editorial-opening,.deeper .week-intro,.deeper .week-connection,.deeper .week-outcomes,.deeper .editorial-frame{margin-top:14px}
.chapter-foot{margin:30px 0 8px;padding:20px 0 0;border-top:1px solid var(--line)}
.takeaway{font-size:15px;line-height:1.6;margin:0 0 16px;max-width:76ch;padding-left:16px;border-left:3px solid var(--accent,#a52d34)}
.takeaway b{font-weight:600}
.chapter-nav{display:flex;flex-wrap:wrap;justify-content:space-between;gap:10px}
.chapter-nav button{max-width:100%;white-space:normal;text-align:left}
.chapter-nav .primary{margin-left:auto}
.how-to{margin:30px 0 26px}
.how-to h2{font:400 22px/1.2 var(--serif);margin:0 0 14px}
.how-to .card p{margin:0;font-size:13.5px;line-height:1.6}
.how-to .card .eyebrow{margin-bottom:8px}
.frame-wrap{border:1px solid var(--line);background:var(--surface)}
.frame-wrap iframe{display:block;width:100%;border:0;min-height:420px}
.frame-toolbar{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:10px;padding:10px 14px;border-bottom:1px solid var(--line);font-size:12px;color:var(--muted)}
.machine-panel-note{font-size:13px;line-height:1.6;color:var(--muted);margin:0 0 12px;max-width:80ch}
@media(max-width:700px){.primer-steps{grid-template-columns:1fr}.formula code{font-size:13px}.primer{padding:16px 15px 14px}.todo{grid-template-columns:1fr;gap:4px;padding:12px 14px}.chapter-head h2{font-size:30px}.chapter-nav .primary{margin-left:0;width:100%}.chapter-nav button{flex:1}}
@media(prefers-reduced-motion:reduce){.chapter-rail,.chapter-bar{transition:none}}
/* Embedded in the journey's Detail drawer: no masthead, no footer, chapters only. */
html[data-embed] .masthead,html[data-embed] footer.sources{display:none}html[data-embed] .shell{padding-top:10px}html[data-embed] .chapter-bar{top:0}
.chapter{scroll-margin-top:66px}