/* Jet Engine Simulator: guide, engine and calculator pages. Same world as the home page: a test cell at night,
   obsidian ground, the afterburner gradient used sparingly, cyan for live numbers. Built for reading: one column
   of about 70 characters, generous line height, real tables for numbers. */
:root {
  --void: #07060c; --deck: #0e0c17; --deck2: #141120;
  --line: rgba(170, 150, 255, 0.14); --line2: rgba(170, 150, 255, 0.28);
  --ink: #f2effb; --mute: #b3aecb; --dim: #8f8aab;
  --violet: #8b5cff; --pink: #ff3d8b; --burn: #ff7a2f; --cyan: #5ce1ff; --ok: #63e6a0; --crit: #ff4d5e;
  --burner: linear-gradient(100deg, #8b5cff 0%, #ff3d8b 50%, #ff7a2f 100%);
  --f-display: "Unbounded", "Arial Black", "Helvetica Neue", system-ui, sans-serif;
  --f-body: "Barlow", system-ui, -apple-system, "Segoe UI", sans-serif;
  --f-mono: "IBM Plex Mono", ui-monospace, "SF Mono", Menlo, monospace;
  color-scheme: dark;
}
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--void); color: var(--ink); font: 400 17.5px/1.65 var(--f-body); }
body::before { content: ""; position: fixed; inset: 0 0 auto; height: env(safe-area-inset-top, 0px); background: var(--void); z-index: 30; }
a { color: var(--cyan); text-underline-offset: 3px; text-decoration-thickness: 1px; }
a:hover { color: #9cefff; }
:focus-visible { outline: 2px solid var(--cyan); outline-offset: 3px; border-radius: 4px; }
img, svg { max-width: 100%; height: auto; }
.wrap { width: 100%; max-width: 1120px; margin: 0 auto; padding-left: max(16px, env(safe-area-inset-left, 0px)); padding-right: max(16px, env(safe-area-inset-right, 0px)); }
.skip { position: absolute; left: -9999px; top: 8px; z-index: 50; padding: 8px 12px; border-radius: 8px; background: var(--ink); color: var(--void); }
.skip:focus { left: 12px; }

/* ---------- header */
.top { position: sticky; top: env(safe-area-inset-top, 0px); z-index: 20; background: rgba(7, 6, 12, .92); border-bottom: 1px solid var(--line); }
.top .wrap { display: flex; align-items: center; gap: 18px; min-height: 60px; }
.brand { display: inline-flex; align-items: center; gap: 10px; flex: none; color: var(--ink); text-decoration: none; font: 800 14px/1 var(--f-display); letter-spacing: .02em; text-transform: uppercase; }
.brand:hover { color: #fff; }
.mark { width: 18px; height: 18px; border-radius: 50%; border: 3px solid var(--burn); box-shadow: inset 0 0 0 3px var(--void), inset 0 0 0 7px var(--violet); }
.nav { display: flex; align-items: center; gap: 4px; margin-left: auto; overflow-x: auto; scrollbar-width: none; }
.nav::-webkit-scrollbar { display: none; }
.nav a { flex: none; padding: 8px 11px; border-radius: 9px; color: var(--mute); text-decoration: none; font: 500 12.5px/1 var(--f-mono); letter-spacing: .05em; text-transform: uppercase; }
.nav a:hover, .nav a[aria-current="page"] { color: var(--ink); background: rgba(255, 255, 255, .05); }
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 9px; min-height: 44px; padding: 0 18px; border-radius: 12px; border: 1px solid var(--line2); background: rgba(255, 255, 255, .03); color: var(--ink); text-decoration: none; font: 600 13px/1 var(--f-mono); letter-spacing: .06em; text-transform: uppercase; }
.btn:hover { color: #fff; border-color: rgba(170, 150, 255, .5); background: rgba(255, 255, 255, .06); }
.btn.hot { border: 0; color: #fff; background: var(--burner); box-shadow: 0 8px 28px rgba(255, 61, 139, .28); }
.btn.hot:hover { filter: brightness(1.08); }
.nav .btn { min-height: 36px; padding: 0 13px; margin-left: 6px; font-size: 12px; }
@media (max-width: 720px) { .top .wrap { flex-wrap: wrap; gap: 4px 12px; padding-block: 10px 6px; } .nav { margin-left: 0; width: 100%; } .nav a { padding: 7px 9px; } }

/* ---------- article */
main { padding-block: 26px 70px; }
.crumbs { display: flex; flex-wrap: wrap; gap: 6px; margin: 0 0 26px; font: 500 12px/1.4 var(--f-mono); letter-spacing: .05em; color: var(--dim); text-transform: uppercase; }
.crumbs a { color: var(--mute); text-decoration: none; }
.crumbs a:hover { color: var(--ink); }
.crumbs span[aria-hidden] { color: var(--dim); }
.hero { display: grid; grid-template-columns: minmax(0, 1fr); gap: 26px; margin-bottom: 40px; }
.eyebrow { margin: 0; font: 500 12px/1 var(--f-mono); letter-spacing: .22em; text-transform: uppercase; color: var(--burn); }
h1 { margin: 12px 0 0; font: 800 clamp(30px, 5.4vw, 54px)/1.04 var(--f-display); letter-spacing: -.01em; text-wrap: balance; max-width: 22ch; }
h1 .grad, .grad { background: var(--burner); -webkit-background-clip: text; background-clip: text; color: transparent; }
.lede { margin: 18px 0 0; max-width: 64ch; color: var(--mute); font-size: 19px; line-height: 1.6; }
.ctas { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 24px; }
.note { margin: 10px 0 0; color: var(--dim); font-size: 14.5px; }
.shot { margin: 0; border-radius: 16px; overflow: hidden; border: 1px solid var(--line2); background: #0b1015; box-shadow: 0 24px 70px rgba(0, 0, 0, .5); }
.shot img { display: block; width: 100%; height: auto; aspect-ratio: 16 / 9; }
.shot figcaption, figure figcaption { padding: 10px 14px; color: var(--dim); font-size: 14px; border-top: 1px solid var(--line); background: var(--deck); }
.body { display: grid; grid-template-columns: minmax(0, 1fr); gap: 0; max-width: 760px; }
.body > * { min-width: 0; }
.body h2 { margin: 46px 0 0; font: 600 clamp(22px, 3vw, 28px)/1.2 var(--f-display); letter-spacing: -.005em; text-wrap: balance; scroll-margin-top: 90px; }
.body h3 { margin: 28px 0 0; font: 600 18px/1.35 var(--f-body); color: var(--ink); scroll-margin-top: 90px; }
.body p, .body ul, .body ol { margin: 14px 0 0; color: #d9d5ea; }
.body li { margin: 6px 0; }
.body li::marker { color: var(--burn); }
.body strong { color: var(--ink); font-weight: 600; }
.body code, .mono { font: 500 .92em/1 var(--f-mono); color: var(--cyan); }
.eq { margin: 16px 0 0; padding: 14px 18px; border-radius: 12px; border: 1px solid var(--line); background: var(--deck); font: 500 16px/1.7 var(--f-mono); color: var(--ink); overflow-x: auto; }
.eq small { display: block; color: var(--dim); font: 400 14px/1.5 var(--f-body); margin-top: 4px; }
.callout { margin: 22px 0 0; padding: 16px 18px; border-radius: 14px; border: 1px solid rgba(255, 122, 47, .35); background: linear-gradient(120deg, rgba(255, 122, 47, .08), rgba(139, 92, 255, .06)); }
.callout p { margin: 6px 0 0; }
.callout p:first-child { margin-top: 0; }
.tbl { margin: 18px 0 0; overflow-x: auto; border: 1px solid var(--line); border-radius: 14px; }
table { width: 100%; border-collapse: collapse; font-size: 15.5px; }
th, td { padding: 10px 14px; text-align: left; border-bottom: 1px solid var(--line); vertical-align: top; }
thead th { font: 500 11.5px/1.3 var(--f-mono); letter-spacing: .08em; text-transform: uppercase; color: var(--dim); background: var(--deck); white-space: nowrap; }
tbody tr:last-child th, tbody tr:last-child td { border-bottom: 0; }
td.n, th.n { text-align: right; font-family: var(--f-mono); font-size: 14px; white-space: nowrap; }
tbody th[scope="row"] { white-space: nowrap; font-weight: 600; }
.tbl th, .tbl td { padding: 10px 12px; }
.tag { display: inline-block; margin-left: 6px; padding: 2px 7px; border-radius: 6px; font: 600 10.5px/1.4 var(--f-mono); letter-spacing: .06em; vertical-align: 1px; color: var(--void); background: var(--ok); }
.tag.pro { background: var(--burner); color: #fff; }
.diagram { margin: 22px 0 0; border-radius: 14px; overflow: hidden; border: 1px solid var(--line); background: var(--deck); }
.diagram svg { display: block; width: 100%; height: auto; }
.steps { counter-reset: st; list-style: none; padding: 0; }
.steps li { counter-increment: st; position: relative; padding-left: 44px; margin: 14px 0 0; }
.steps li::before { content: counter(st); position: absolute; left: 0; top: 1px; width: 30px; height: 30px; border-radius: 50%; display: grid; place-items: center; font: 700 13px/1 var(--f-mono); color: var(--void); background: var(--burn); }

/* ---------- glossary */
.glossary { margin: 18px 0 0; }
.glossary dt { margin: 26px 0 0; font: 600 18px/1.3 var(--f-body); color: var(--ink); scroll-margin-top: 90px; }
.glossary dt a.self { color: inherit; text-decoration: none; }
.glossary dt a.self:hover::after { content: " #"; color: var(--dim); }
.glossary dd { margin: 6px 0 0; color: #d9d5ea; }
.az { display: flex; flex-wrap: wrap; gap: 6px; margin: 18px 0 0; }
.az a { padding: 4px 9px; border-radius: 7px; border: 1px solid var(--line); text-decoration: none; font: 500 12.5px/1.4 var(--f-mono); color: var(--mute); }
.az a:hover { color: var(--ink); border-color: var(--line2); }

/* ---------- calculators */
.calc { margin: 22px 0 0; padding: clamp(16px, 3vw, 24px); border-radius: 18px; border: 1px solid var(--line2); background: linear-gradient(180deg, var(--deck2), var(--deck)); }
.calc h2 { margin-top: 0 !important; }
.fields { display: grid; grid-template-columns: repeat(auto-fill, minmax(min(100%, 210px), 1fr)); gap: 14px 16px; margin-top: 16px; }
.field label { display: block; font: 600 13px/1.35 var(--f-body); letter-spacing: .01em; color: var(--mute); }
.field .in { display: flex; align-items: stretch; margin-top: 6px; border: 1px solid var(--line2); border-radius: 10px; background: #0a0912; }
.field .in:focus-within { border-color: var(--cyan); box-shadow: 0 0 0 3px rgba(92, 225, 255, .15); }
.field input { flex: 1; min-width: 0; padding: 10px 12px; border: 0; background: transparent; color: var(--ink); font: 500 16px/1.2 var(--f-mono); outline: none; }
.field .u { display: grid; place-items: center; padding: 0 11px; border-left: 1px solid var(--line); color: var(--dim); font: 500 13px/1 var(--f-mono); white-space: nowrap; }
.field small { display: block; margin-top: 5px; color: var(--dim); font-size: 13px; line-height: 1.4; }
.calc-actions { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 16px; }
.calc-actions button { cursor: pointer; }
.output { margin-top: 20px; }
.out-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(100%, 240px), 1fr)); gap: 12px; }
.big { padding: 14px 16px; border-radius: 14px; border: 1px solid var(--line); background: #0a0912; }
.big span { display: block; font: 500 11.5px/1.3 var(--f-mono); letter-spacing: .08em; text-transform: uppercase; color: var(--dim); }
.big b { display: block; margin-top: 6px; font: 700 clamp(24px, 4vw, 32px)/1.1 var(--f-mono); color: var(--cyan); }
.big small { display: block; margin-top: 4px; color: var(--dim); font-size: 13.5px; }
table.res { margin-top: 14px; border: 1px solid var(--line); border-radius: 14px; overflow: hidden; display: table; }
table.res th { font: 400 15px/1.4 var(--f-body); color: var(--mute); }
table.res td { text-align: right; font: 500 15px/1.4 var(--f-mono); color: var(--ink); white-space: nowrap; }
table.res td small, table.res th small { color: var(--dim); font-weight: 400; }
.calc-err { margin: 0; padding: 12px 14px; border-radius: 12px; border: 1px solid rgba(255, 77, 94, .45); background: rgba(255, 77, 94, .08); color: #ffc6cc; }
svg.ts .grid { stroke: rgba(170, 150, 255, .12); stroke-width: 1; }
svg.ts .axis { stroke: rgba(170, 150, 255, .45); stroke-width: 1.4; }
svg.ts .tick, svg.ts .al { fill: var(--dim); font: 500 11px var(--f-mono); }
svg.ts .c { fill: none; stroke-width: 3; stroke-linecap: round; }
svg.ts .comp { stroke: var(--cyan); }
svg.ts .heat { stroke: var(--burn); }
svg.ts .turb { stroke: var(--pink); }
svg.ts .cool { stroke: var(--violet); stroke-dasharray: 6 6; }
svg.ts .pt { fill: var(--void); stroke: var(--ink); stroke-width: 2; }
svg.ts .pl { fill: var(--ink); font: 700 13px var(--f-mono); }

/* ---------- engine diagrams (inline SVG) */
svg.eng text { font: 500 12px var(--f-mono); fill: var(--mute); }
svg.eng .lbl { fill: var(--ink); font-weight: 600; }
svg.eng .st { fill: var(--burn); font-weight: 700; }
svg.eng .stl line { stroke: rgba(170, 150, 255, .28); stroke-width: 1.2; stroke-dasharray: 4 5; }
svg.eng .stn circle { fill: var(--void); stroke: var(--burn); stroke-width: 1.6; }
svg.eng .case { fill: none; stroke: #c9c4de; stroke-width: 3; stroke-linejoin: round; }
svg.eng .duct { fill: none; stroke: #8f8aab; stroke-width: 2.4; }
svg.eng .hub { fill: #1b1828; stroke: #8f8aab; stroke-width: 1.4; }
svg.eng .bc line { stroke: var(--cyan); stroke-width: 2.4; }
svg.eng .bt line { stroke: var(--pink); stroke-width: 3; }
svg.eng .fan line { stroke: #9cefff; stroke-width: 3; }
svg.eng .flame path { fill: rgba(255, 122, 47, .55); stroke: var(--burn); stroke-width: 1.4; }
svg.eng .plume { fill: rgba(255, 122, 47, .22); }
svg.eng .air path, svg.eng .core path, svg.eng .byp path { fill: none; stroke-width: 2.4; stroke-linecap: round; }
svg.eng .air path { stroke: rgba(242, 239, 251, .55); marker-end: url(#aw); }
svg.eng .core path { stroke: var(--burn); marker-end: url(#ao); }
svg.eng .byp path { stroke: var(--cyan); marker-end: url(#ac); }
svg.eng #aw path { fill: rgba(242, 239, 251, .7); } svg.eng #ao path { fill: var(--burn); } svg.eng #ac path { fill: var(--cyan); }
svg.eng .ttl { fill: var(--ink); font: 600 14px var(--f-display); }

/* ---------- related + footer */
.related { margin-top: 64px; padding-top: 30px; border-top: 1px solid var(--line); }
.related h2 { margin: 0; font: 600 20px/1.2 var(--f-display); }
.cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(min(100%, 250px), 1fr)); gap: 12px; margin: 18px 0 0; padding: 0; list-style: none; }
.cards a { display: block; height: 100%; padding: 16px 18px; border-radius: 14px; border: 1px solid var(--line); background: var(--deck); color: var(--ink); text-decoration: none; transition: border-color .2s, transform .2s; }
.cards a:hover { border-color: rgba(255, 122, 47, .5); transform: translateY(-2px); }
.cards b { display: block; font: 600 16.5px/1.3 var(--f-body); }
.cards span { display: block; margin-top: 6px; color: var(--mute); font-size: 14.5px; line-height: 1.5; }
@media (prefers-reduced-motion: reduce) { .cards a { transition: none; } .cards a:hover { transform: none; } }
.foot { border-top: 1px solid var(--line); background: #05040a; padding-block: 40px calc(30px + env(safe-area-inset-bottom, 0px)); }
.sitemap { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(100%, 180px), 1fr)); gap: 24px; }
.sitemap h2 { margin: 0 0 10px; font: 500 11.5px/1.3 var(--f-mono); letter-spacing: .14em; text-transform: uppercase; color: var(--dim); }
.sitemap ul { margin: 0; padding: 0; list-style: none; }
.sitemap li { margin: 7px 0; }
.sitemap a { color: var(--mute); text-decoration: none; font-size: 15px; }
.sitemap a:hover { color: var(--ink); }
.legal { display: flex; flex-wrap: wrap; gap: 8px 18px; margin-top: 30px; padding-top: 18px; border-top: 1px solid var(--line); color: var(--dim); font: 500 12px/1.5 var(--f-mono); }
.legal a { color: var(--dim); }