.ai4u-sub .b3-page{padding:32px 0;margin:0;color:var(--ink);scroll-margin-top:100px}
.b3-page .b3-inner{width:min(calc(100% - 48px),1120px);margin:0 auto;min-width:0}
.b3-page .b3-eyebrow{margin:0 0 16px;font-size:12px;font-weight:700;color:var(--blue)}
.b3-page .b3-title{font-size:clamp(40px,4.4vw,66px);line-height:1.18;letter-spacing:-.055em;margin:0 0 28px}
.b3-page .b3-heading{font-size:clamp(28px,3vw,44px);line-height:1.35;letter-spacing:-.055em;margin:0;max-width:900px}
.b3-page .b3-lead{margin:24px 0;color:var(--ink);font-weight:600}
.b3-page .b3-body{margin:0;max-width:900px;color:var(--muted)}
.ai4u-sub .b3-bg-wash{background:var(--wash)}
.ai4u-sub .b3-bg-deep{background:var(--deep);color:var(--white,#fff)}
.b3-bg-deep :is(.b3-eyebrow,.b3-lead,.b3-body){color:var(--white,#fff)}
.b3-page .b3-layout{display:grid;grid-template-columns:minmax(0,1.25fr) minmax(0,1fr);gap:48px;align-items:center}
.b3-page .b3-copy,.b3-page .b3-map{min-width:0}
.b3-page :is(ul,ol){list-style:none;padding:0;margin:32px 0 0}
.b3-page li{margin:0;line-height:1.85;font-size:17px;min-width:0}
.b3-page .b3-progress{margin:0;border-left:2px solid var(--blue);padding-left:28px}
.b3-progress li{padding:24px;border-bottom:1px solid var(--line);background:var(--wash);transition:border-color .6s ease}
.b3-page.b3-active .b3-progress li{border-color:var(--blue)}
.b3-page .b3-swimlane li{padding:24px 0;border-bottom:1px solid var(--line)}
.b3-page .b3-boundaries{margin:0;border-left:2px solid var(--blue);padding-left:28px}
.b3-boundaries li+li{margin-top:32px}
.b3-page .b3-disclosure{margin-top:32px}
.b3-page .b3-detail{border-top:1px solid var(--line);padding:24px 0;margin:0}
.b3-detail summary{cursor:pointer;font-weight:700;min-height:40px;line-height:1.85}
.b3-page .b3-detail-copy{margin:24px 0 0}
.b3-page .b3-build,.b3-page .b3-validation{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:32px}
.b3-build li{padding-left:24px;border-left:2px solid var(--blue)}
.b3-validation li{padding-top:24px;border-top:2px solid var(--blue)}
.b3-page .b3-network{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:32px;border-top:1px solid var(--line);padding-top:32px}
.b3-network li{border-left:1px solid var(--line);padding-left:24px}
.b3-page .b3-changes{border-left:2px solid var(--blue);padding-left:32px}
.b3-changes li{padding:24px 0;border-bottom:1px solid var(--line)}
.b3-page .b3-ready{display:flex;flex-wrap:wrap;gap:24px}
.b3-page .b3-actions{margin-top:32px}
.b3-button a{background:var(--blue);color:var(--white,#fff);border-radius:7px;padding:14px 22px;min-height:48px;text-decoration:none;transition:background-color .2s ease}
.b3-button a:hover{background:var(--ink)}
.b3-page :is(a,summary):focus-visible{outline:3px solid var(--blue);outline-offset:4px}
.b3-bg-deep summary:focus-visible{outline-color:var(--white,#fff)}
.b3-page .reveal{animation:b3-entry .6s ease both}
@keyframes b3-entry{from{transform:translateY(8px)}to{transform:translateY(0)}}
@media(max-width:900px){.b3-page .b3-layout{grid-template-columns:1fr;gap:32px}.b3-page .b3-build,.b3-page .b3-validation,.b3-page .b3-network{grid-template-columns:1fr;gap:28px}.b3-page .b3-progress{padding-left:24px}.b3-page .b3-scope-notes{max-width:100%}}
@media(max-width:580px){.ai4u-sub .b3-page{padding:24px 0}.b3-page .b3-inner{width:calc(100% - 40px)}.b3-page .b3-title{font-size:40px}.b3-page li{font-size:15px}.b3-page .b3-progress li{padding:24px 16px}}
@media(prefers-reduced-motion:reduce){.b3-page .reveal{animation:none}.b3-progress li,.b3-button a{transition:none}}

.b3-page.b3-bg-wash .b3-body{color:var(--ink)}
.b3-page.b3-bg-deep :is(h2,p,li,summary){color:var(--white,#fff)}