/* A diagonal archive in native document flow. Styles remain inside the exhibit. */
.history-exhibit{--history-count:24;--history-step:190px;position:relative;isolation:isolate;width:100vw;left:50%;margin:75px 0 0;transform:translateX(-50%);height:calc(100svh + var(--history-count)*var(--history-step));color:#e8e9e6;background:#121719;--history-accent:#b9d9d6;overflow:visible;scroll-margin-top:0}
.history-pin{position:sticky;top:0;height:100svh;min-height:680px;overflow:hidden;isolation:isolate;background:radial-gradient(ellipse at 75% 30%,#2d454331,transparent 60%),#121719}
.history-pin::before,.history-pin::after{content:"";position:absolute;left:0;right:0;pointer-events:none;z-index:20}.history-pin::before{top:0;height:235px;background:linear-gradient(#121719 15%,#121719dd 63%,#12171900)}.history-pin::after{bottom:0;height:190px;background:linear-gradient(#12171900,#121719ee 65%,#121719)}
.history-heading{position:absolute;z-index:22;left:max(38px,calc((100vw - 1220px)/2));top:116px;pointer-events:none}
.history-kicker{font:10px/1.5 var(--sans,Arial,sans-serif);letter-spacing:.2em;color:#8b9b9e;margin:0 0 11px}
.history-heading h2{font-family:"Songti SC","STSong",serif!important;font-size:clamp(25px,2.4vw,38px)!important;font-weight:400!important;line-height:1.4;margin:0!important;color:#e9ece7!important;letter-spacing:.01em}
.history-year{position:absolute;z-index:0;right:3.5%;top:92px;font:400 clamp(140px,19vw,290px)/1 Georgia,"Times New Roman",serif;letter-spacing:-.09em;color:#c8d6d34d;pointer-events:none;user-select:none}
.history-diagonal{position:absolute;inset:0;pointer-events:none;z-index:0;opacity:.8}
.history-diagonal::before{content:"";position:absolute;left:50%;top:50%;height:1px;width:170%;background:linear-gradient(90deg,transparent,#a6c3c229 20%,#a6c3c229 80%,transparent);transform:translate(-50%,-50%) rotate(29deg)}
.history-diagonal i{position:absolute;left:50%;top:50%;width:3px;height:3px;border-radius:50%;background:#8da5a67a}.history-diagonal i:nth-child(1){transform:translate(-430px,-237px)}.history-diagonal i:nth-child(2){transform:translate(430px,237px)}
.history-cards{position:absolute;inset:0;z-index:3}
.history-card{position:absolute;left:50%;top:51%;width:min(720px,64vw);min-height:350px;display:grid;grid-template-columns:43% 1fr;background:#e2e8e5;color:#243135;border:1px solid #ffffff52;border-radius:3px;overflow:hidden;box-shadow:0 26px 70px #0004;transform-origin:center;will-change:transform,opacity;pointer-events:none}
.history-card[hidden]{display:none}.history-card.is-current{pointer-events:auto}
.history-card[data-palette="1"]{background:#e9e5db}.history-card[data-palette="2"]{background:#dae6e7}.history-card[data-palette="3"]{background:#dce1e6}
.history-card-visual{position:relative;min-height:350px;overflow:hidden;background:#1d3339;color:#d6e5e0;border-right:1px solid #1424211a;display:flex;align-items:center;justify-content:center}
.history-card[data-palette="1"] .history-card-visual{background:#413d33;color:#ede6d0}.history-card[data-palette="2"] .history-card-visual{background:#20363a;color:#d5e6e4}.history-card[data-palette="3"] .history-card-visual{background:#2b3441;color:#dae0ed}
.history-card-visual img{display:block;width:100%;height:100%;position:absolute;inset:0;object-fit:cover;object-position:center;filter:saturate(.65)}
.history-card-visual::after{content:"";position:absolute;inset:0;background:linear-gradient(transparent 55%,#08121765);pointer-events:none}
.history-card-category{position:absolute;left:19px;bottom:18px;z-index:2;color:#ebefea;font:10px/1.4 var(--sans,Arial,sans-serif);letter-spacing:.08em}
.history-type-motif{padding:30px;position:relative;z-index:2;font:400 30px/1.45 Georgia,"Songti SC",serif;overflow-wrap:anywhere;text-wrap:balance;text-align:center}.history-type-motif.is-formula{font:italic 27px/1.6 Georgia,"Times New Roman",serif;letter-spacing:-.03em}
.history-type-orbit{position:absolute;width:210px;height:210px;border:1px solid #b4d1d325;border-radius:50%;transform:rotate(-25deg) scaleY(.55);box-shadow:0 0 0 35px #9fbdc20b,0 0 0 70px #9fbdc20b;pointer-events:none}
.history-card-copy{padding:27px 30px 25px;display:flex;flex-direction:column;position:relative}
.history-card-topline{display:flex;align-items:center;justify-content:space-between;gap:12px;margin-bottom:18px}
.history-card-topline time{font:400 35px/1 Georgia,serif;letter-spacing:-.055em;color:#3c5356}
.history-source{color:#718581!important;font:19px/1 Georgia,serif;padding:7px;text-decoration:none!important;border:0!important}
.history-card h3{font-family:var(--sans,Arial,sans-serif)!important;color:#213133!important;font-size:23px!important;line-height:1.4!important;font-weight:550!important;letter-spacing:-.035em!important;margin:0 0 13px!important;text-wrap:balance}
.history-description{font-family:var(--sans,Arial,sans-serif);font-size:13px!important;line-height:1.9!important;color:#536260!important;margin:0!important;text-wrap:pretty}
.history-people{font:10px/1.7 var(--sans,Arial,sans-serif);color:#7b8780;margin:12px 0 0;letter-spacing:.01em}
.history-course{font:11px/1.6 var(--sans,Arial,sans-serif);display:flex;align-items:center;justify-content:space-between;gap:20px;padding-top:18px;margin-top:auto;color:#3e5958!important;text-decoration:none!important;border:0!important}
.history-course span{font-size:17px}.history-exhibit a:focus-visible{outline:2px solid #729999!important;outline-offset:5px}
.history-rail{position:absolute;z-index:24;left:max(38px,calc((100vw - 1080px)/2));right:max(38px,calc((100vw - 1080px)/2));bottom:33px;padding:20px 0 0}
.history-rail-caption{display:flex;gap:20px;align-items:baseline;margin-bottom:13px;font:10px/1.4 var(--sans,Arial,sans-serif);letter-spacing:.06em;color:#8fa09f}.history-current-label{font:26px/1 Georgia,serif;color:#dce6e1;letter-spacing:-.04em}.history-count{margin-left:auto;font-variant-numeric:tabular-nums;color:#829390}
.history-track{height:1px;background:#819c9238;position:relative}.history-track-progress{position:absolute;inset:0;background:#b1ceca;transform:scaleX(0);transform-origin:0 50%}.history-track-cursor{position:absolute;left:0;top:-3px;background:#e3eeea;width:7px;height:7px;border-radius:50%;transform:translateX(-50%)}
.history-ticks{position:relative;height:23px;margin-top:12px}.history-ticks a{position:absolute;left:var(--tick-position);transform:translateX(-50%);font:10px/1.5 var(--sans,Arial,sans-serif);color:#859590!important;text-decoration:none!important;border:none!important;letter-spacing:.03em;padding:4px 0}.history-ticks a:first-child{transform:none}.history-ticks a:last-child{transform:translateX(-100%)}.history-ticks a[aria-current]{color:#e4ede8!important}
.history-index{border-bottom:1px solid #75898630;margin:0 0 50px;padding:19px 0;color:inherit}.history-index>summary{display:flex;gap:14px;align-items:center;cursor:pointer;list-style:none;font:12px/1.5 var(--sans,Arial,sans-serif);color:inherit;opacity:.65}.history-index>summary::-webkit-details-marker{display:none}.history-index>summary::before{content:"+";font-size:16px}.history-index[open]>summary::before{content:"−"}.history-index>summary span{margin-left:auto;font-size:10px;letter-spacing:.08em}
.history-index ol{list-style:none;margin:24px 0 0;padding:0;display:grid;grid-template-columns:1fr 1fr;gap:0 35px}.history-index li{display:grid;grid-template-columns:65px 1fr;gap:20px;padding:20px 0;border-top:1px solid #75898625}.history-index time{font:22px/1.5 Georgia,serif}.history-index a{font-size:14px;color:inherit!important;text-decoration:none}.history-index p{font-size:12px;line-height:1.8;opacity:.65;margin:8px 0 0}
@media(min-width:1600px){.history-card{width:790px;min-height:390px}.history-card-visual{min-height:390px}.history-card-copy{padding:34px 36px}.history-card h3{font-size:25px!important}.history-description{font-size:14px!important}.history-card-topline time{font-size:43px}}
@media(max-width:950px){.history-card{width:min(690px,76vw);grid-template-columns:40% 1fr;min-height:325px}.history-card-visual{min-height:325px}.history-card-copy{padding:23px}.history-card h3{font-size:21px!important}.history-heading{top:108px;left:30px}.history-card-topline{margin-bottom:14px}.history-year{top:140px;right:3%}}
@media(max-width:680px){.history-exhibit{--history-step:205px;margin-top:42px}.history-pin{min-height:690px}.history-heading{left:22px;top:93px}.history-kicker{font-size:9px;margin-bottom:8px}.history-heading h2{font-size:26px!important}.history-year{top:122px;right:4%;font-size:140px}.history-card{top:53%;width:calc(100vw - 44px);max-width:400px;min-height:0;grid-template-columns:1fr;box-shadow:0 18px 55px #0005}.history-card-visual{height:124px;min-height:124px;border-right:0}.history-card-visual img{object-position:center 36%}.history-card-category{bottom:11px;left:17px;font-size:9px}.history-type-motif,.history-type-motif.is-formula{font-size:25px;padding:25px 35px}.history-type-orbit{width:150px;height:150px}.history-card-copy{padding:18px 21px}.history-card-topline{margin:0 0 11px}.history-card-topline time{font-size:28px}.history-source{position:absolute;right:15px;top:16px}.history-card h3{font-size:20px!important;line-height:1.35!important;margin-bottom:9px!important}.history-description{font-size:12px!important;line-height:1.75!important}.history-people{font-size:9px;margin-top:8px}.history-course{font-size:10px;padding-top:13px}.history-rail{left:22px;right:22px;bottom:22px;padding-top:16px}.history-rail-caption{gap:13px;margin-bottom:12px}.history-current-label{font-size:24px}.history-era,.history-count{font-size:9px}.history-ticks{margin-top:10px}.history-ticks a{font-size:9px}.history-index ol{grid-template-columns:1fr}.history-index li{gap:13px}}
@media(max-height:740px) and (min-width:681px){.history-heading{top:100px}.history-heading h2{font-size:27px!important}.history-card{top:54%;min-height:305px}.history-card-visual{min-height:305px}.history-card-copy{padding:20px 25px}.history-card h3{font-size:21px!important}.history-card-topline{margin-bottom:11px}.history-description{font-size:12px!important}.history-rail{bottom:22px}}
@media(prefers-reduced-motion:reduce){.history-card{will-change:auto}.history-diagonal{opacity:.35}}
@media(max-width:680px){.history-pin::before{height:225px}.history-pin::after{height:155px}.history-ticks a[data-history-year="2017"],.history-ticks a[data-history-year="2022"]{display:none}}
@media(max-height:690px){.history-pin{min-height:0}.history-heading{top:82px}.history-heading h2{font-size:23px!important}.history-kicker{margin-bottom:7px}.history-pin::before{height:182px}.history-pin::after{height:120px}.history-rail{bottom:11px}.history-card{top:53%}.history-card-visual{min-height:260px}.history-card-copy{padding:17px 22px}.history-description{font-size:11px!important;line-height:1.7!important}.history-card h3{font-size:19px!important}.history-card-topline{margin-bottom:10px}}
@media(max-height:690px) and (max-width:680px){.history-card{top:53%}.history-card-visual{height:75px;min-height:75px}.history-card-copy{padding:14px 19px}.history-card h3{font-size:18px!important}.history-card-topline time{font-size:24px}.history-people{margin-top:5px}.history-course{padding-top:9px}.history-type-motif,.history-type-motif.is-formula{font-size:20px}.history-card-category{display:none}}
@media print{.history-exhibit{display:none}.history-index{display:block}.history-index>ol{display:grid!important}.history-index>summary{display:none}}

.history-formula{font:italic 14px/1.6 Georgia,"Times New Roman",serif;color:#4f666b;margin:12px 0 0;overflow-wrap:anywhere}
.history-description{font-size:14px!important;line-height:1.8!important}.history-people{font-size:11px}.history-course{font-size:12px}
.history-card[data-event="dartmouth"] .history-card-visual img,.history-card[data-event="backprop"] .history-card-visual img,.history-card[data-event="cnn"] .history-card-visual img{object-position:center;filter:saturate(.25)}
.history-card[data-event="perceptron"] .history-card-visual img{object-position:45% center}
.history-card[data-event="gpt6-astra"] .history-type-motif{font-size:35px;line-height:1.35}
@media(max-width:680px){.history-description{font-size:13px!important;line-height:1.75!important}.history-people{font-size:10px}.history-formula{font-size:12px;margin-top:8px}.history-course{font-size:11px}}
@media(max-height:690px){.history-description{font-size:12px!important;line-height:1.7!important}.history-formula{font-size:11px;margin-top:6px}}

/* Narrative titles name the question; subtitles identify the actual method or publication. */
.history-scope{font:11px/1.6 var(--sans,Arial,sans-serif);color:#8fa5a2;margin:9px 0 0;letter-spacing:.04em}
.history-node-subtitle{font:11px/1.55 var(--sans,Arial,sans-serif);color:#788681;margin:-5px 0 12px;overflow-wrap:anywhere}
.history-index-parts{padding:14px 0 20px}.history-index-parts section{padding:23px 0 8px;border-top:1px solid #a4b4ab25}.history-index-parts h3{font:400 21px/1.6 "Songti SC",serif;color:#d6dfda;margin:0 0 18px}.history-index .history-index-parts ol{margin-top:0}.history-index .history-index-parts li{grid-template-columns:96px minmax(0,1fr)}.history-index .history-index-parts time{font-size:17px;line-height:1.5}.history-index a.history-index-course{font-size:11px;color:#c2ad91!important;display:inline-block;margin-top:8px}
@media(max-width:680px){.history-scope{font-size:9px;margin-top:6px}.history-node-subtitle{font-size:10px;margin:-3px 0 9px}.history-card-copy{padding-top:16px;padding-bottom:16px}.history-index-parts h3{font-size:18px}.history-index .history-index-parts li{grid-template-columns:78px minmax(0,1fr);gap:13px}.history-index .history-index-parts time{font-size:14px}}
@media(max-height:690px){.history-scope{display:none}.history-node-subtitle{font-size:9px;line-height:1.4;margin:-3px 0 6px}.history-card-topline{margin-bottom:8px}.history-card h3{font-size:17px!important;line-height:1.35!important;margin-bottom:8px!important}.history-description{font-size:11px!important;line-height:1.6!important}}