.bhg-guide{--bhg-pad:clamp(22px,4.5vw,72px);--bhg-gap:clamp(32px,5vw,72px)}
.bhg-hero{padding:34px var(--bhg-pad) 64px;max-width:1600px;margin:auto}
.bhg-breadcrumb{display:flex;flex-wrap:wrap;gap:14px;color:var(--muted);font-size:12px;margin-bottom:55px}.bhg-breadcrumb a{text-decoration:underline;text-underline-offset:4px}
.bhg-hero-grid{display:grid;grid-template-columns:minmax(0,1.1fr) minmax(0,1fr);gap:var(--bhg-gap);align-items:center}.bhg-hero-grid>div,.bhg-hero-grid>figure{min-width:0}
.bhg-hero h1{font:clamp(57px,6.7vw,102px)/1.02 var(--display);letter-spacing:-.052em;margin:25px 0}.bhg-hero h1 em{color:var(--aqua);font-weight:400}.bhg-deck{font-size:clamp(17px,1.5vw,22px);line-height:1.65;max-width:38ch;color:#c5d0ce}.bhg-byline{display:flex;flex-wrap:wrap;gap:10px 25px;color:var(--muted);font-size:12px;line-height:1.6;margin:25px 0 32px}.bhg-byline a{text-decoration:underline}
.bhg-hero-diagram{margin:0}.bhg-hero-diagram img{width:100%;height:auto}.bhg-hero-diagram figcaption,.bhg-figure figcaption{color:var(--muted);font-size:13px;line-height:1.65;margin-top:16px;max-width:75ch}
.bhg-jump{display:grid;grid-template-columns:repeat(6,minmax(0,1fr));padding:0 var(--bhg-pad);max-width:1600px;margin:0 auto 16px}.bhg-jump a{border-top:1px solid var(--line);padding:17px 8px 18px 0;display:flex;gap:10px;font-size:12px;line-height:1.4}.bhg-jump a span{color:var(--copper);font-size:10px}.bhg-jump a:hover{color:var(--aqua)}
.bhg-section{padding:clamp(54px,6vw,90px) var(--bhg-pad);max-width:1600px;margin:auto;border-top:1px solid var(--line);scroll-margin-top:24px}.bhg-section h2{font:clamp(35px,4.5vw,66px)/1.08 var(--display);letter-spacing:-.04em;margin:15px 0 32px}.bhg-section h2 em{font-weight:400;color:var(--aqua)}.bhg-section h3{font:clamp(23px,2vw,31px)/1.2 var(--display);letter-spacing:-.02em}
.bhg-reading{display:grid;grid-template-columns:minmax(240px,340px) minmax(0,1fr);gap:var(--bhg-gap)}.bhg-section-intro{align-self:start;min-width:0}.bhg-prose{min-width:0;max-width:80ch}.bhg-prose p{font-size:17px;line-height:1.85;color:#c8d2cf;margin-bottom:25px}.bhg-prose>.text-link{line-height:1.6;white-space:normal}
.bhg-citations{white-space:nowrap;font-size:.76em}.bhg-citations a{color:var(--copper);text-decoration:underline;text-underline-offset:3px}.bhg-figure{margin:32px 0}.bhg-figure img{width:100%;height:auto;border:1px solid var(--line);background:#0c171e}
.bhg-definition-grid,.bhg-evidence-grid,.bhg-open-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:24px}.bhg-definition-grid>article,.bhg-evidence-grid>article,.bhg-open-grid>article{min-width:0;padding:28px;border:1px solid var(--line);background:var(--panel)}.bhg-definition-grid p,.bhg-evidence-grid p,.bhg-open-grid p,.bhg-note p,.bhg-section-lead{font-size:16px;line-height:1.8;color:#c5cfcd}.bhg-key{display:inline-block;font-size:12px;letter-spacing:.13em;border-bottom:3px solid;padding-bottom:8px;margin-bottom:20px}.bhg-key-horizon{color:var(--copper)}.bhg-key-photon{color:var(--aqua)}.bhg-key-orbit{color:#c1afd9}
.bhg-note{margin-top:30px;padding:25px 28px;border-left:3px solid var(--copper);background:#14232b}.bhg-note strong{font-weight:500;color:var(--cream)}.bhg-note p{max-width:105ch;margin:13px 0 0}.bhg-section-lead{max-width:90ch;margin:20px 0 32px}.bhg-evidence-grid>article>span,.bhg-source-grid>article>span,.bhg-reading-grid>a>span{font-size:10px;letter-spacing:.16em;color:var(--copper)}.bhg-evidence-grid h3,.bhg-open-grid h3{margin:20px 0}.bhg-evidence-grid a{font-size:13px;text-decoration:underline;text-underline-offset:4px;line-height:1.65}
.bhg-comparison{background:linear-gradient(130deg,#0e1d26,#0a1219)}.bhg-tool-controls[hidden],.bhg-tool-live[hidden]{display:none}.bhg-tool-controls{border:1px solid var(--line);padding:26px;margin:30px 0}.bhg-presets{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:15px}.bhg-presets button{background:#0c161e;border:1px solid #607779;color:var(--cream);padding:17px 16px;min-height:65px;text-align:left}.bhg-presets button[aria-pressed=true]{border-color:var(--copper);background:#2c2925}.bhg-presets button span{display:block;color:var(--muted);font-size:12px;margin-top:8px}.bhg-slider-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:32px;margin-top:30px}.bhg-slider-grid label{display:flex;flex-wrap:wrap;gap:10px;align-items:center;font-size:14px}.bhg-slider-grid output{color:var(--aqua);font-variant-numeric:tabular-nums;margin-left:auto}.bhg-slider-grid input{width:100%;min-height:44px;accent-color:var(--copper);margin:0}.bhg-slider-grid small{width:100%;font-size:12px;line-height:1.65;color:var(--muted)}.bhg-reset{margin-top:23px;min-height:44px;background:transparent;border:1px solid var(--line);padding:10px 17px;color:var(--cream)}
.bhg-tool-live{display:grid;grid-template-columns:1fr 1fr;gap:30px}.bhg-tool-live>div{min-width:0;padding:28px;background:#0a141b;border:1px solid var(--line)}.bhg-tool-live svg{width:100%;height:auto;margin-top:15px}.bhg-tool-live p:not(.eyebrow){color:#c4cfcb;line-height:1.7;font-size:14px}.bhg-position{color:var(--aqua)!important}.bhg-tool-results dl{margin:0}.bhg-tool-results dl>div{padding:15px 0 22px;border-bottom:1px solid var(--line)}.bhg-tool-results dt{color:var(--muted);font-size:13px;line-height:1.6}.bhg-tool-results dd{font-family:var(--display);font-size:clamp(28px,2.9vw,44px);line-height:1.25;color:var(--cream);margin:10px 0 0;overflow-wrap:anywhere;font-variant-numeric:tabular-nums}.bhg-tool-results dd.bhg-unit-note{font:13px/1.7 var(--sans);color:var(--muted)}.bhg-insight{margin:23px 0 0;border-left:2px solid var(--aqua);padding-left:17px}
.bhg-model-details{margin:30px 0;border:1px solid var(--line);padding:0 24px}.bhg-model-details summary,.bhg-questions summary{cursor:pointer;min-height:54px;padding:18px 0;color:var(--cream);line-height:1.6}.bhg-model-details p{font-size:14px;line-height:1.85;color:#c5cfcd;max-width:100ch}.bhg-static-comparison{margin-top:30px}.bhg-table-scroll{overflow-x:auto;max-width:100%;border:1px solid var(--line)}.bhg-static-comparison table{width:100%;border-collapse:collapse;font-size:14px;min-width:610px}.bhg-static-comparison caption{text-align:left;font-size:12px;line-height:1.7;padding:16px;color:var(--muted)}.bhg-static-comparison th,.bhg-static-comparison td{padding:15px 18px;text-align:left;border-top:1px solid var(--line);line-height:1.6;white-space:nowrap}.bhg-static-comparison th{font-weight:500}.bhg-static-comparison>p{color:var(--muted);font-size:13px;line-height:1.7}
.bhg-questions{max-width:1250px}.bhg-questions details{border-top:1px solid var(--line);padding:0 4px}.bhg-questions summary{font-size:18px}.bhg-questions details p{max-width:80ch;line-height:1.85;font-size:16px;color:#c5cfcd;padding:0 22px 18px}.bhg-reading-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:24px}.bhg-reading-grid>a{display:flex;flex-direction:column;padding:28px;border:1px solid var(--line);background:var(--panel);min-width:0;transition:border-color .2s,background .2s}.bhg-reading-grid>a:hover{border-color:var(--copper);background:#17262e}.bhg-reading-grid h3{margin:22px 0 18px}.bhg-reading-grid p{font-size:15px;line-height:1.8;color:#bfcac7}.bhg-reading-grid b{font-size:12px;font-weight:500;color:var(--aqua);margin-top:auto;padding-top:15px;line-height:1.6}
.bhg-source-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,340px),1fr));gap:22px}.bhg-source-grid article{min-width:0;padding:26px;border:1px solid var(--line);scroll-margin-top:25px}.bhg-source-grid article:target{border:2px solid var(--copper);background:#1b292e;padding:25px}.bhg-source-grid article:target>span{font-weight:700;color:#f2d2aa}.bhg-source-grid h3{font-size:24px;margin:17px 0;overflow-wrap:anywhere}.bhg-source-grid p{font-size:14px;line-height:1.8;color:var(--muted)}.bhg-source-return{display:inline-block;text-decoration:underline;text-underline-offset:4px;font-size:12px;line-height:1.6;margin-top:7px}.bhg-update-note{color:var(--muted);max-width:90ch;font-size:13px;line-height:1.8;margin:30px 0 0}.bhg-guide :focus-visible{outline:2px solid var(--aqua);outline-offset:5px}
@media(min-width:960px) and (min-height:640px){.bhg-section-intro{position:sticky;top:28px}}
@media(max-width:1100px){.bhg-jump{grid-template-columns:repeat(4,minmax(0,1fr))}.bhg-reading-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.bhg-definition-grid,.bhg-evidence-grid,.bhg-open-grid{grid-template-columns:repeat(auto-fit,minmax(min(100%,300px),1fr))}}
@media(max-width:959px){.bhg-hero-grid,.bhg-reading{grid-template-columns:1fr}.bhg-hero h1{font-size:clamp(56px,9vw,88px)}.bhg-hero h1 br:last-child{display:none}.bhg-hero-diagram{max-width:580px;margin:auto}.bhg-hero{padding-bottom:40px}.bhg-section-intro h2{margin-bottom:0}.bhg-prose{max-width:85ch}.bhg-tool-live{grid-template-columns:1fr}.bhg-source-grid{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media(max-width:700px){.bhg-breadcrumb{margin-bottom:36px}.bhg-jump{grid-template-columns:repeat(3,minmax(0,1fr))}.bhg-jump a{font-size:11px;gap:7px}.bhg-definition-grid,.bhg-evidence-grid,.bhg-open-grid,.bhg-reading-grid,.bhg-source-grid,.bhg-slider-grid{grid-template-columns:1fr}.bhg-presets{gap:8px}.bhg-presets button{padding:12px 10px;font-size:12px}.bhg-presets button span{font-size:11px;line-height:1.5}.bhg-tool-controls{padding:17px}.bhg-tool-live>div{padding:21px}.bhg-prose p{font-size:16px}.bhg-section{scroll-margin-top:15px}.bhg-section h2{font-size:41px}.bhg-section h3{font-size:26px}.bhg-questions summary{font-size:17px}.bhg-byline{flex-direction:column;gap:7px}}
@media(max-width:370px){.bhg-jump{grid-template-columns:repeat(2,minmax(0,1fr))}.bhg-presets{grid-template-columns:1fr}.bhg-hero h1{font-size:50px}}
@media(prefers-reduced-motion:reduce){.bhg-reading-grid>a{transition:none}}
@media print{.bhg-jump,.bhg-tool-controls,.bhg-tool-live,.bhg-hero .button{display:none!important}.bhg-hero-grid,.bhg-reading{display:block}.bhg-section-intro{position:static}.bhg-source-grid,.bhg-reading-grid{grid-template-columns:1fr}.bhg-section{break-inside:auto}.bhg-guide{color:#111}.bhg-section p{color:#222}}