/* D2C and app chapters share one system: sticky vertical bowtie (left) + seven-step timeline (right). */
.chap-body{display:grid;grid-template-columns:minmax(0,46%) minmax(0,1fr);gap:9%;align-items:start}
.chap-map{position:sticky;top:110px;padding:24px 0}
.bowtie-top{display:flex;justify-content:space-between;align-items:center;gap:14px;margin-bottom:22px;flex-wrap:wrap}
.bt-legend{display:flex;gap:16px;font-size:12px;color:#666}
.bt-legend>span{display:inline-flex;align-items:center;gap:8px}
.bt-legend i{width:11px;height:11px;display:inline-block}
.bt-legend .k-pre{background:#1a1a1a}.bt-legend .k-post{background:var(--red)}
.vbow{list-style:none;margin:0;padding:0;display:grid;gap:6px;position:relative}
.vbow li{display:grid;grid-template-columns:104px 1fr 112px;align-items:center;column-gap:14px;min-height:28px}
.bt-name{font:600 10.5px/1.2 var(--sans);letter-spacing:.1em;text-transform:uppercase;color:#9a9a9a;transition:color .3s}
.bt-bar{height:24px;display:flex;align-items:center;justify-content:center}
.bt-bar i{position:relative;display:block;height:100%;width:calc(var(--h)*1%);border:1px dashed #c9c6bf;border-radius:3px}
.bt-bar i:after{content:'';position:absolute;inset:-1px;border-radius:3px;background:#1a1a1a;transform:scaleX(var(--f,1))}
.vbow li.post .bt-bar i:after{background:var(--red)}
.vbow li.knot .bt-bar i{width:16px;height:16px;border:0;transform:rotate(45deg)}
.vbow li.knot .bt-bar i:after{inset:0;background:var(--red);transform:scale(var(--f,1))}
.bt-trig{font-size:12px;color:#9a9a9a;transition:color .3s}
.vbow li.on .bt-name{color:#171717}
.vbow li.cur .bt-name{color:var(--red)}
.vbow li.cur .bt-trig{color:#171717}
.bt-dot{position:absolute;left:0;top:0;width:10px;height:10px;margin:-5px 0 0 -5px;border-radius:50%;background:#fff;border:3px solid var(--red);opacity:0;pointer-events:none;z-index:2}
.bowtie-detail{display:grid;grid-template-columns:auto 1fr;gap:6px 16px;align-items:baseline;border-top:1px solid #d6d4ce;margin-top:20px;padding-top:16px;min-height:118px;align-content:start}
.bt-count{font:12px monospace;color:#8a8a8a}
.bt-title{font:400 28px/1.05 var(--display);text-transform:uppercase;margin:0;color:#171717}
.bt-desc{grid-column:1/-1;font-size:15px;line-height:1.55;color:#555}
.bt-ch{grid-column:1/-1;font:600 11px var(--sans);letter-spacing:.08em;color:var(--red)}
.bt-note{font-size:11px;color:#888;margin-top:10px}
/* Timeline: same weight in both chapters */
.chap-steps{padding-top:24px}
.tl{list-style:none;margin:0;padding:0;position:relative;border-left:1px solid #c9c6bf}
.tl:before{content:'';position:absolute;top:0;left:-1px;width:2px;height:100%;background:var(--red);transform:scaleY(var(--tl,0));transform-origin:top}
.tl>li{position:relative;padding:28px 0 36px 36px;min-height:210px;border-top:1px solid #dcdad4}
.tl>li:before{content:'';position:absolute;left:-5px;top:35px;width:9px;height:9px;border-radius:50%;background:#c9c6bf}
.tl>li.active:before{background:var(--red)}
.tl .num{font:12px monospace;color:#8a8a8a}
.tl h3{font:400 40px/1.05 var(--display);text-transform:uppercase;margin:14px 0 12px;color:#9a9a9a;transition:color .3s}
.tl p{font-size:17px;line-height:1.65;color:#666;max-width:34ch}
.tl li.active h3{color:#171717}.tl li.active .num{color:var(--red)}
/* Dark chapter (apps) */
#apps .bt-legend,#apps .bt-note{color:#8a8a8a}
#apps .bt-legend .k-pre{background:#e9e7e2}
#apps .bt-bar i{border-color:#4a4a4a}
#apps .bt-bar i:after{background:#e9e7e2}
#apps .vbow li.post .bt-bar i:after,#apps .vbow li.knot .bt-bar i:after{background:var(--red)}
#apps .bt-name,#apps .bt-trig{color:#6f6f6f}
#apps .vbow li.on .bt-name{color:#f2f2f2}
#apps .vbow li.cur .bt-name{color:var(--red)}
#apps .vbow li.cur .bt-trig{color:#f2f2f2}
#apps .bt-dot{background:#151515}
#apps .bowtie-detail{border-color:#333}
#apps .bt-title{color:#fff}#apps .bt-desc{color:#aaa}
#apps .tl{border-color:#444}#apps .tl>li{border-color:#333}#apps .tl>li:before{background:#444}#apps .tl>li.active:before{background:var(--red)}
#apps .tl h3{color:#6f6f6f}#apps .tl li.active h3{color:#fff}#apps .tl p{color:#aaa}
@media(max-width:900px){
 .chap-body{grid-template-columns:1fr;gap:30px}
 .chap-map{position:static;padding:0}
 .vbow li{grid-template-columns:92px 1fr;column-gap:10px}
 .bt-trig{display:none}
 .bt-dot{display:none}
 .bt-title{font-size:26px}
 .tl>li{min-height:0;padding:24px 0 28px 26px}
 .tl h3{font-size:32px}
 .tl p{font-size:16px}
}
@media(prefers-reduced-motion:reduce){.chap-map{position:static}.bt-bar i:after{transform:none!important}.tl:before{transform:none}}

.tl>li h3,.tl>li .num,.vbow li{transition:color .45s ease}.bt-title,.bt-desc,.bt-ch{animation-duration:.45s}