/* Fold & Soar: paper, ink and one warm accent. Serif headings, sans body, no web fonts. */
:root{
  --paper:#f6f1e5;--card:#fffdf7;--ink:#1b2440;--muted:#5a6479;--accent:#d7461b;--accent-ink:#b8360f;--accent-soft:#ffdccd;
  --sky:#d9ebf1;--line:#ddd3bf;--grid:rgba(27,36,64,.055);--shadow:0 1px 0 rgba(27,36,64,.06),0 10px 30px -18px rgba(27,36,64,.45);
  --serif:"Iowan Old Style","Palatino Linotype","Book Antiqua",Palatino,Georgia,serif;
  --sans:ui-sans-serif,-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;
  --mono:ui-monospace,"SF Mono",Menlo,Consolas,monospace;
  --ease:cubic-bezier(.2,.8,.2,1);--spring:cubic-bezier(.3,1.5,.5,1);
  --d-ink:#1b2440;--d-accent:#d7461b;
  color-scheme:light;
}
@media (prefers-color-scheme:dark){:root:not([data-theme="light"]){
  --paper:#131929;--card:#1b2336;--ink:#eef1f7;--muted:#a8b1c5;--accent:#ff7a4d;--accent-ink:#ff9a75;--accent-soft:#4a2a22;
  --sky:#17233a;--line:#2d3753;--grid:rgba(238,241,247,.05);--shadow:0 1px 0 rgba(0,0,0,.3),0 12px 30px -16px rgba(0,0,0,.7);color-scheme:dark}}
:root[data-theme="dark"]{--paper:#131929;--card:#1b2336;--ink:#eef1f7;--muted:#a8b1c5;--accent:#ff7a4d;--accent-ink:#ff9a75;--accent-soft:#4a2a22;--sky:#17233a;--line:#2d3753;--grid:rgba(238,241,247,.05);color-scheme:dark}

*{box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{margin:0;background:var(--paper);color:var(--ink);font:17.5px/1.65 var(--sans);overflow-x:hidden}
img,svg{max-width:100%}
a{color:var(--accent-ink);text-decoration-thickness:1px;text-underline-offset:3px}
a:hover{text-decoration-thickness:2px}
:focus-visible{outline:3px solid var(--accent);outline-offset:3px;border-radius:4px}
h1,h2,h3{font-family:var(--serif);font-weight:700;line-height:1.12;letter-spacing:-.015em;margin:0 0 .5em;text-wrap:balance}
h1{font-size:clamp(34px,5.4vw,60px)}
h2{font-size:clamp(25px,3vw,32px)}
h3{font-size:20px}
p{margin:0 0 1em;text-wrap:pretty}
.small{font-size:14px;color:var(--muted)}
.skip{position:absolute;left:16px;top:-80px;background:var(--card);padding:10px 14px;z-index:30;border-radius:8px}
.skip:focus{top:10px}
.wrap{width:min(1160px,calc(100% - 32px));margin-inline:auto}
.eyebrow{font:700 13px/1 var(--sans);letter-spacing:.14em;text-transform:uppercase;color:var(--accent-ink);margin:0 0 16px}
.lead{font-size:clamp(18px,2vw,21px);line-height:1.55;color:var(--ink);max-width:640px}

/* buttons */
.button{display:inline-flex;align-items:center;gap:8px;padding:12px 20px;border-radius:999px;background:var(--ink);color:var(--paper);font-weight:700;text-decoration:none;border:2px solid var(--ink);transition:transform .25s var(--spring),box-shadow .25s var(--ease)}
.button:hover{transform:translateY(-2px);box-shadow:0 8px 18px -10px var(--ink)}
.button:active{transform:translateY(0) scale(.98)}
.button.ghost{background:transparent;color:var(--ink)}
.button.small{padding:9px 16px;font-size:15px}

/* header */
.site-header{position:sticky;top:0;z-index:20;background:color-mix(in srgb,var(--paper) 88%,transparent);backdrop-filter:blur(10px);-webkit-backdrop-filter:blur(10px);border-bottom:1px solid var(--line)}
.header-inner{display:flex;align-items:center;justify-content:space-between;gap:20px;min-height:64px}
.brand{display:inline-flex;gap:10px;align-items:center;color:var(--ink);text-decoration:none;font:700 21px/1 var(--serif);letter-spacing:-.02em;white-space:nowrap}
.brand i{font-style:italic;color:var(--accent-ink)}
.brand svg{width:30px;height:30px;flex:none;transition:transform .5s var(--spring)}
.brand:hover svg{transform:translate(3px,-3px) rotate(-8deg)}
.site-header nav{display:flex;gap:4px;align-items:center}
.site-header nav a{color:var(--ink);text-decoration:none;font-size:15px;font-weight:600;padding:8px 12px;border-radius:999px;white-space:nowrap;transition:background .2s}
.site-header nav a:hover{background:var(--grid)}
.site-header nav a[aria-current="page"]{background:var(--accent-soft)}
.nav-app{color:var(--ink);text-decoration:none;font-size:15px;font-weight:650;padding:7px 14px;border-radius:999px;border:1.5px solid var(--ink);white-space:nowrap;transition:background .2s,color .2s}
.nav-app:hover{background:var(--ink);color:var(--paper)}
.header-end{display:flex;align-items:center;gap:8px}

/* hero */
.hero{position:relative;overflow:hidden;padding:64px 0 56px;border-bottom:1px solid var(--line);
  background:linear-gradient(var(--grid) 1px,transparent 1px) 0 0/28px 28px,linear-gradient(90deg,var(--grid) 1px,transparent 1px) 0 0/28px 28px,var(--sky)}
.hero-sky{position:absolute;inset:0;width:100%;height:100%;pointer-events:none}
.hero-trail{fill:none;stroke:var(--ink);stroke-opacity:.18;stroke-width:1.5;stroke-dasharray:2 9;stroke-linecap:round}
.hero-glider path{fill:var(--card);stroke:var(--ink);stroke-width:1.4;stroke-linejoin:round}
.hero-glider{opacity:0}
.hero-glider.flying{opacity:1}
.hero-grid{position:relative;display:grid;grid-template-columns:1.1fr .9fr;gap:56px;align-items:center}
.hero h1 .hl{background:linear-gradient(transparent 62%,var(--accent-soft) 62%);padding:0 .08em}
.actions{display:flex;gap:12px;flex-wrap:wrap;margin-top:28px}
.hero-plate{margin:0}
.hero-plate figcaption{font-size:13px;color:var(--muted);margin-top:10px;text-align:center}

/* fold player */
.fold-player{position:relative;aspect-ratio:5/5.4;background:var(--card);border:1.5px solid var(--ink);border-radius:18px;box-shadow:8px 8px 0 var(--ink);overflow:hidden}
.fp-frame{position:absolute;inset:14px 14px 58px;display:grid;place-items:center;opacity:0;transition:opacity .35s var(--ease)}
.fp-frame.on{opacity:1}
.fp-frame svg{width:100%;height:100%}
.fp-bar{position:absolute;left:0;right:0;bottom:0;height:50px;display:flex;align-items:center;justify-content:space-between;gap:10px;padding:0 10px 0 16px;border-top:1px solid var(--line);font-size:15px;background:var(--card)}
.fp-caption b{font-family:var(--mono);color:var(--accent-ink);margin-right:6px}
.fp-toggle{border:1.5px solid var(--ink);background:none;color:var(--ink);border-radius:999px;width:34px;height:34px;font-size:12px;cursor:pointer}
.fp-ticks{position:absolute;left:16px;right:16px;bottom:49px;display:flex;gap:3px;margin:0;padding:0;list-style:none}
.fp-ticks li{flex:1;height:3px;border-radius:2px;background:var(--line);transition:background .3s}
.fp-ticks li.done{background:var(--accent)}

/* sections */
.section{padding:64px 0}
.section-title{font-size:clamp(26px,3.2vw,36px)}
.section-head{display:flex;justify-content:space-between;align-items:end;gap:28px;margin-bottom:26px}
.section-head p{max-width:420px;margin:0;color:var(--muted);font-size:15px}
.three{list-style:none;padding:0;margin:28px 0 0;display:grid;grid-template-columns:repeat(3,1fr);gap:18px;counter-reset:n}
.three li{background:var(--card);border:1px solid var(--line);border-radius:16px;padding:24px;position:relative;box-shadow:var(--shadow)}
.three .n{font:700 44px/1 var(--serif);color:var(--accent);display:block;margin-bottom:10px}
.three p{color:var(--muted);font-size:16px}
.three a{font-weight:700;text-decoration:none}
.hangar-band{background:var(--card);border-block:1px solid var(--line);padding:64px 0}
.shelf{margin-top:34px}
.shelf-head{display:flex;align-items:baseline;gap:16px;flex-wrap:wrap;border-bottom:1px dashed var(--line);padding-bottom:8px;margin-bottom:14px}
.shelf-head h3{margin:0;font-size:22px}
.shelf-head p{margin:0;color:var(--muted);font-size:15px}
.more{margin:36px 0 0;text-align:center}

/* plane cards */
.plane-grid{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(auto-fill,minmax(176px,1fr));gap:14px}
.shelf .plane-grid{grid-template-columns:repeat(5,minmax(0,1fr))}
.plane-grid.compact{grid-template-columns:repeat(auto-fill,minmax(150px,1fr))}
.plane-card a{display:flex;flex-direction:column;height:100%;padding:12px 14px 14px;border-radius:14px;background:var(--paper);border:1px solid var(--line);color:var(--ink);text-decoration:none;transition:border-color .2s,box-shadow .3s var(--ease),transform .3s var(--ease)}
.hangar-band .plane-card a{background:var(--paper)}
.plane-card a:hover{border-color:var(--ink);box-shadow:var(--shadow);transform:translateY(-2px)}
.pc-art{display:grid;place-items:center;aspect-ratio:16/10;margin:-4px -4px 8px;border-radius:10px;background:linear-gradient(var(--grid) 1px,transparent 1px) 0 0/16px 16px,linear-gradient(90deg,var(--grid) 1px,transparent 1px) 0 0/16px 16px,var(--sky)}
.pc-art img{width:88%;height:88%;object-fit:contain;transition:transform .5s var(--spring);filter:drop-shadow(0 6px 4px rgba(27,36,64,.14))}
.plane-card a:hover .pc-art img{transform:translate(6px,-7px) rotate(-5deg)}
.pc-name{font:700 18px/1.2 var(--serif)}
.pc-meta{display:flex;align-items:center;gap:8px;font-size:13px;color:var(--muted);margin-top:4px}
.pc-chips{display:flex;flex-wrap:wrap;gap:4px;margin-top:8px}
.pc-chips span{font-size:11.5px;font-weight:650;padding:2px 8px;border-radius:999px;background:var(--grid);color:var(--muted)}
.dots{display:inline-flex;gap:3px;vertical-align:middle}
.dots i{width:7px;height:7px;border-radius:50%;border:1.5px solid currentColor;opacity:.55}
.dots i.on{background:var(--accent);border-color:var(--accent);opacity:1}
.plane-card.hide{display:none}
.plane-card.pop{animation:pop .45s var(--spring) both}
@keyframes pop{from{opacity:0;transform:translateY(8px) scale(.97)}}

/* article cards */
.article-list{list-style:none;padding:0;margin:0;display:grid;grid-template-columns:repeat(auto-fill,minmax(200px,1fr));gap:14px}
.article-card a{display:grid;grid-template-columns:48px 1fr;column-gap:14px;height:100%;padding:20px;border-radius:14px;background:var(--card);border:1px solid var(--line);color:var(--ink);text-decoration:none;transition:border-color .2s,transform .3s var(--ease)}
.article-card a:hover{border-color:var(--ink);transform:translateY(-2px)}
.article-card svg{grid-row:span 3;width:48px;height:48px}
.article-card svg *{fill:none;stroke:var(--ink);stroke-width:2;stroke-linecap:round;stroke-linejoin:round}
.article-card svg circle{fill:var(--accent);stroke:none}
.article-card svg .i-sheet{fill:var(--card)}
.article-card svg .i-b{fill:var(--accent-soft)}
.article-card a:hover svg .i-path{stroke:var(--accent);stroke-dasharray:60;animation:draw .9s var(--ease)}
@keyframes draw{from{stroke-dashoffset:60}}
.ac-kicker{font-size:12px;font-weight:700;letter-spacing:.08em;text-transform:uppercase;color:var(--accent-ink)}
.ac-title{font:700 19px/1.25 var(--serif);margin:4px 0 6px}
.ac-sum{font-size:15px;color:var(--muted);line-height:1.5}

/* app band */
.app-band{background:var(--ink);color:var(--paper);padding:64px 0}
.app-band .eyebrow{color:#ffb599}
.app-band .button{background:var(--paper);color:var(--ink);border-color:var(--paper)}
.app-grid{display:grid;grid-template-columns:1.3fr 1fr;gap:48px;align-items:center}
.app-notes{border:1px dashed color-mix(in srgb,var(--paper) 40%,transparent);border-radius:16px;padding:24px}
.app-notes p{opacity:.85;margin:0}

/* article + guide heroes */
.article-hero{padding:40px 0 30px;border-bottom:1px solid var(--line);background:linear-gradient(var(--grid) 1px,transparent 1px) 0 0/28px 28px,linear-gradient(90deg,var(--grid) 1px,transparent 1px) 0 0/28px 28px,var(--sky)}
.article-hero h1{max-width:900px}
.crumbs{font-size:14px;color:var(--muted);margin-bottom:18px}
.crumbs a{color:var(--muted)}
.byline{font-size:14px;color:var(--muted);margin:0}
.guide-hero{padding:36px 0 36px;border-bottom:1px solid var(--line);background:linear-gradient(var(--grid) 1px,transparent 1px) 0 0/28px 28px,linear-gradient(90deg,var(--grid) 1px,transparent 1px) 0 0/28px 28px,var(--sky)}
.guide-hero-grid{display:grid;grid-template-columns:1.15fr .85fr;gap:40px;align-items:center}
.guide-hero h1{font-size:clamp(32px,4.6vw,52px)}
.facts{display:grid;grid-template-columns:repeat(4,auto);gap:4px 26px;margin:22px 0 0;justify-content:start}
.facts div{border-top:2px solid var(--ink);padding-top:6px}
.facts dt{font-size:12px;font-weight:700;letter-spacing:.06em;text-transform:uppercase;color:var(--muted)}
.facts dt small{text-transform:none;letter-spacing:0;font-weight:500}
.facts dd{margin:2px 0 0;font-weight:650}
.facts dd a{color:var(--ink)}
.plate{margin:0}
.plate-art,.plate.small>svg{background:var(--card);border:1.5px solid var(--ink);border-radius:18px;box-shadow:6px 6px 0 var(--ink);padding:18px}
.plate-art svg{display:block;width:100%;height:auto;max-height:300px}
.plate figcaption{font-size:13px;color:var(--muted);margin-top:10px}
.plate-art svg{animation:hover-in 1s var(--ease) both}
@keyframes hover-in{from{transform:translate(-18px,14px) rotate(4deg);opacity:0}}

/* guide layout */
.guide-layout{display:grid;grid-template-columns:minmax(0,1fr) 270px;gap:56px;padding:44px 0 72px}
.guide-body{min-width:0;max-width:760px}
.guide-body>h2{margin-top:56px;padding-top:8px;scroll-margin-top:80px}
.guide-body h2:first-child{margin-top:0}
.guide-aside{position:sticky;top:84px;align-self:start;display:grid;gap:18px}
.toc h2,.app-box h2{font-family:var(--sans);font-size:12px;letter-spacing:.1em;text-transform:uppercase;color:var(--muted);margin-bottom:10px}
.toc ol{list-style:none;padding:0;margin:0;border-left:2px solid var(--line)}
.toc a{display:block;padding:5px 0 5px 14px;margin-left:-2px;border-left:2px solid transparent;color:var(--ink);text-decoration:none;font-size:15px;line-height:1.35;transition:border-color .2s,color .2s}
.toc a:hover,.toc a.active{border-left-color:var(--accent);color:var(--accent-ink)}
.app-box{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:18px}
.app-box p{font-size:15px;color:var(--muted)}

/* before you start */
.prep{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:18px 20px}
.prep p{margin:0 0 12px;font-size:16px}
.units{display:inline-flex;position:relative;border:1.5px solid var(--ink);border-radius:999px;padding:3px;margin:0 0 12px}
.units button{position:relative;z-index:1;border:0;background:none;color:var(--ink);font:650 14px var(--sans);padding:6px 14px;border-radius:999px;cursor:pointer;transition:color .3s}
.units button small{font-weight:500;opacity:.7}
.units::before{content:"";position:absolute;top:3px;bottom:3px;left:3px;width:calc(50% - 3px);border-radius:999px;background:var(--ink);transition:transform .35s var(--spring)}
.units button[aria-pressed="true"]{color:var(--paper)}
:root[data-units="a4"] .units::before{transform:translateX(100%)}
.m-a4{display:none}
:root[data-units="a4"] .m-a4{display:inline}
:root[data-units="a4"] .m-letter{display:none}
.legend{display:flex;flex-wrap:wrap;align-items:center;gap:6px 14px;font-size:14px;color:var(--muted)}
.legend>span:not(.legend-note){white-space:nowrap}
.lg{display:inline-block;width:22px;height:12px;vertical-align:middle;margin-right:3px}
.lg-move{background:#ffd8c8;border:1px solid #1b2440}
.lg-line{border-top:2.5px dashed #d7461b;height:0}
.lg-ghost{border:1.5px dotted #d7461b}
.legend-note{flex-basis:100%;font-size:13px}

/* steps */
.fold-steps{list-style:none;padding:0;margin:0;display:grid;gap:14px}
.fold-step{display:grid;grid-template-columns:220px 1fr;gap:22px;align-items:start;padding:14px;border-radius:16px;border:1px solid var(--line);background:var(--card);scroll-margin-top:80px}
.fold-step.final{border-color:var(--ink);box-shadow:var(--shadow)}
.diagram-wrap{position:relative;display:block;width:100%;aspect-ratio:1/1.12;padding:8px;border:0;border-radius:10px;cursor:pointer;background:linear-gradient(rgba(27,36,64,.05) 1px,transparent 1px) 0 0/14px 14px,linear-gradient(90deg,rgba(27,36,64,.05) 1px,transparent 1px) 0 0/14px 14px,#f3efe4}
.diagram-wrap svg{width:100%;height:100%;display:block}
.fold-step.final .diagram-wrap{aspect-ratio:1/.8}
.replay{position:absolute;right:8px;bottom:6px;font-size:16px;color:#5a6479;opacity:.55;transition:opacity .2s,transform .6s var(--ease)}
.diagram-wrap:hover .replay{opacity:1}
.diagram-wrap.playing .replay{transform:rotate(360deg);opacity:1;color:#d7461b}
.fold-step.final .replay{display:none}
.step-text{padding-top:4px}
.step-no{font:600 13px var(--mono);color:var(--accent-ink);letter-spacing:.05em}
.step-text h3{margin:2px 0 8px;font-size:21px}
.step-text p{margin:0 0 8px}
.tip{font-size:15px;color:var(--muted);padding-left:12px;border-left:3px solid var(--accent-soft)}
.diagram polygon{vector-effect:non-scaling-stroke;stroke:#1b2440;stroke-width:1.1;stroke-linejoin:round}
.d-paper{fill:#fffdf7}
.diagram .d-still{stroke-opacity:.38}
.d-scale path{fill:none;stroke:#5a6479;stroke-width:.03}
.d-scale text{fill:#5a6479;font-family:var(--sans)}
.d-move{fill:#ffd8c8}
.d-ghost{fill:none;stroke:#d7461b!important;stroke-dasharray:3 3}
.d-line{stroke:#d7461b;stroke-width:.06;stroke-dasharray:.22 .13}
.d-arrow{fill:none;stroke:#d7461b;stroke-width:.06;stroke-linecap:round}

/* check + fly */
.check-grid{display:grid;grid-template-columns:260px 1fr;gap:26px;align-items:start}
.plate.small>svg{display:block;width:100%;height:auto;padding:12px;box-shadow:4px 4px 0 var(--ink);border-radius:14px}
.launch-lead{font-size:18px}
.feature-notes{padding:0;list-style:none;display:grid;gap:10px;margin:18px 0}
.feature-notes li{padding:12px 16px;border-radius:12px;background:var(--card);border:1px solid var(--line)}
.mini-doctor{margin:24px 0;padding:20px;border-radius:16px;border:1.5px dashed var(--ink)}
.mini-doctor h3{margin-bottom:12px}
.mini-doctor dl{display:grid;grid-template-columns:repeat(3,1fr);gap:16px;margin:0 0 12px}
.mini-doctor dt{font-weight:700;font-size:15px}
.mini-doctor dd{margin:4px 0 0;font-size:15px;color:var(--muted)}
.mini-doctor p{margin:0;font-weight:650}
.sim-note{font-size:14px;color:var(--muted);background:var(--grid);padding:12px 16px;border-radius:10px}
h3.also{margin-top:28px;font-size:18px}
.pager{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin:44px 0 20px}
.pager a{display:block;padding:16px 18px;border:1px solid var(--line);border-radius:14px;background:var(--card);text-decoration:none;color:var(--ink);font:700 19px var(--serif);transition:border-color .2s,transform .3s var(--ease)}
.pager a:hover{border-color:var(--ink)}
.pager a[rel="prev"]:hover{transform:translateX(-3px)}
.pager a[rel="next"]{text-align:right}
.pager a[rel="next"]:hover{transform:translateX(3px)}
.pager small{display:block;font:600 12px var(--sans);text-transform:uppercase;letter-spacing:.08em;color:var(--muted)}
.correction{margin-top:12px}

/* prose */
.prose>p,.prose li{max-width:68ch}
.prose h2{margin-top:48px;scroll-margin-top:80px}
.prose .lead{margin-bottom:28px}
.narrow{max-width:720px;padding:40px 0 72px}
.prose ol,.prose ul:not(.article-list):not(.plane-grid){padding-left:22px}
.prose li{margin:6px 0}
.table-wrap{overflow-x:auto;margin:24px 0;border:1px solid var(--line);border-radius:14px;background:var(--card)}
table{border-collapse:collapse;width:100%;font-size:15.5px;min-width:520px}
caption{text-align:left;font-weight:700;padding:14px 16px 4px;font-family:var(--serif);font-size:17px}
th,td{padding:11px 16px;text-align:left;vertical-align:top;border-bottom:1px solid var(--line)}
tbody tr:last-child td{border-bottom:0}
th{font-size:13px;text-transform:uppercase;letter-spacing:.05em;color:var(--muted)}
.note,.contact-card{background:var(--accent-soft);border-radius:12px;padding:16px 18px;margin:20px 0}
.keep-going{margin-top:64px;padding-top:24px;border-top:1px solid var(--line)}
.keep-going h2{margin-top:0}

/* figures */
.figure{margin:30px 0;padding:18px;background:var(--card);border:1px solid var(--line);border-radius:16px}
.figure figcaption{font-size:14px;color:var(--muted);margin-top:12px}
.figure>svg{display:block;width:100%;height:auto;max-height:340px}
.figure text{font-family:var(--sans)}
.f-label{font-size:14px;font-weight:700;fill:var(--ink)}
.f-note{font-size:12.5px;fill:var(--muted)}
.f-path{fill:none;stroke:var(--accent);stroke-width:2;stroke-dasharray:4 5;stroke-linecap:round}
.f-ground{stroke:var(--line);stroke-width:2}
.f-glyph{fill:var(--card);stroke:var(--ink);stroke-width:1.5;stroke-linejoin:round}
.f-wing{fill:none;stroke:var(--ink);stroke-width:3;stroke-linecap:round}
.f-bend{stroke:var(--accent)}
.f-dim{stroke:var(--muted);stroke-width:1.2;fill:none}
.f-sheet-l{fill:color-mix(in srgb,var(--sky) 70%,transparent);stroke:var(--ink);stroke-width:2}
.f-sheet-a{fill:none;stroke:var(--accent);stroke-width:2;stroke-dasharray:6 4}
.f-a4{fill:var(--accent-ink)}
.f-lane{fill:color-mix(in srgb,var(--sky) 60%,transparent);stroke:var(--line);stroke-width:2;rx:10}
.f-release{stroke:var(--ink);stroke-width:3}
.f-marks circle{fill:var(--muted)}
.f-marks .f-median{fill:var(--accent)}
.f-force path{stroke:var(--ink);stroke-width:2.2;fill:none}
.f-glyph.big{stroke-width:2}
.fly-svg .f-plane{opacity:0}.fly-svg.flown .f-plane{opacity:1}.fly-svg.flown .f-plane-rest{opacity:0}
.path-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:12px}
.path-panel{display:flex;flex-direction:column;gap:2px;font-size:14px;cursor:pointer;border-radius:10px;padding:6px;transition:background .2s}
.path-panel:hover{background:var(--grid)}
.path-panel svg{width:100%;height:auto;background:var(--sky);border-radius:8px;margin-bottom:6px}
.path-panel span{color:var(--muted);line-height:1.4}
.outline-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:12px}
.outline-grid a{display:flex;flex-direction:column;align-items:center;gap:6px;color:var(--ink);font-weight:650;text-decoration:none;font-size:15px}
.outline-grid svg{width:100%;height:210px;background:var(--sky);border-radius:10px;padding:6px}
.js .figure .f-marks circle{transform-box:fill-box;transform-origin:center}
.js .figure.seen .f-marks circle{animation:drop .5s var(--spring) both}
.f-marks circle:nth-child(2){animation-delay:.12s!important}.f-marks circle:nth-child(3){animation-delay:.24s!important}.f-marks circle:nth-child(4){animation-delay:.36s!important}.f-marks circle:nth-child(5){animation-delay:.48s!important}
@keyframes drop{from{transform:translateY(-14px) scale(.3);opacity:0}}
.js .figure .f-force path{stroke-dasharray:120;stroke-dashoffset:120}
.js .figure.seen .f-force path{animation:grow 1s var(--ease) forwards}
.f-force:nth-child(4) path{animation-delay:.15s!important}.f-force:nth-child(5) path{animation-delay:.3s!important}
@keyframes grow{to{stroke-dashoffset:0}}

/* hangar */
.filters{display:flex;flex-wrap:wrap;gap:8px;margin-top:24px}
.filters button{font:650 14px var(--sans);padding:7px 14px;border-radius:999px;border:1.5px solid var(--ink);background:var(--card);color:var(--ink);cursor:pointer;transition:background .2s,color .2s,transform .25s var(--spring)}
.filters button:hover{transform:translateY(-1px)}
.filters button[aria-pressed="true"]{background:var(--ink);color:var(--paper)}
.filter-status{margin:10px 0 0;min-height:1.4em}
.family-jump{display:flex;flex-wrap:wrap;gap:6px 18px;margin-top:10px;font-size:15px}
.family-jump a{color:var(--ink);text-decoration:none;border-bottom:1px solid var(--line)}
.family-jump span{font-family:var(--mono);font-size:12px;color:var(--muted)}
.family{padding:44px 0 8px;scroll-margin-top:70px}
.family-head{display:grid;grid-template-columns:300px 1fr;gap:24px;align-items:baseline;margin-bottom:18px;border-top:2px solid var(--ink);padding-top:14px}
.family-head h2{margin:0}
.family-head p{margin:0;color:var(--muted);max-width:640px}
.family.empty{display:none}
.hangar>.wrap{padding-bottom:72px}

/* footer */
.site-footer{border-top:1px solid var(--line);padding:48px 0 40px;background:var(--card)}
.footer-inner{display:grid;grid-template-columns:1fr 1.6fr;gap:40px}
.footer-note p{color:var(--muted);font-size:15px;max-width:360px;margin-top:14px}
.footer-links{display:grid;grid-template-columns:repeat(3,1fr);gap:24px}
.footer-links h2{font:700 12px var(--sans);letter-spacing:.1em;text-transform:uppercase;color:var(--muted);margin-bottom:10px}
.footer-links a{display:block;color:var(--ink);text-decoration:none;font-size:15px;padding:3px 0}
.footer-links a:hover{color:var(--accent-ink)}

/* reveal: only when scripting is on and motion is welcome */
@media (prefers-reduced-motion:no-preference){
  .js .reveal{opacity:0;transform:translateY(14px);transition:opacity .6s var(--ease),transform .6s var(--ease)}
  .js .reveal.in{opacity:1;transform:none}
  @view-transition{navigation:auto}
  ::view-transition-old(root){animation:vt-out .22s var(--ease) both}
  ::view-transition-new(root){animation:vt-in .32s var(--ease) both}
  ::view-transition-group(*){animation-duration:.45s;animation-timing-function:var(--ease)}
}
@keyframes vt-out{to{opacity:0;transform:translateY(-6px)}}
@keyframes vt-in{from{opacity:0;transform:translateY(10px)}}
@media (prefers-reduced-motion:reduce){
  *,*::before,*::after{animation-duration:.01ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important;scroll-behavior:auto!important}
  .hero-glider{display:none}
}

/* responsive */
@media (max-width:960px){
  .hero-grid,.guide-hero-grid,.app-grid{grid-template-columns:1fr;gap:32px}
  .hero-plate{max-width:440px;width:100%;margin-inline:auto}
  .guide-layout{grid-template-columns:1fr;gap:28px}
  .guide-aside{position:static}
  .toc{display:none}
  .facts{grid-template-columns:repeat(2,auto)}
  .plate-art svg{max-height:220px}
  .three{grid-template-columns:1fr}
  .shelf .plane-grid{grid-template-columns:repeat(3,minmax(0,1fr))}
  .family-head{grid-template-columns:1fr;gap:6px}
  .footer-inner{grid-template-columns:1fr}
  .path-grid,.outline-grid{grid-template-columns:repeat(2,1fr)}
}
@media (max-width:720px){
  body{font-size:17px}
  .header-inner{flex-wrap:wrap;gap:4px;padding:10px 0 0;min-height:0}
  .header-end{display:contents}
  .nav-app{order:2;padding:5px 12px;font-size:14px}
  .site-header nav{order:3}
  .site-header nav{width:calc(100% + 32px);margin:0 -16px;padding:4px 12px 8px;overflow-x:auto;scrollbar-width:none}
  .site-header nav::-webkit-scrollbar{display:none}
  .site-header nav a{padding:6px 10px;font-size:14.5px}
  .hero{padding:36px 0 40px}
  .section,.hangar-band,.app-band{padding:44px 0}
  .section-head{flex-direction:column;align-items:start;gap:8px}
  .fold-step{grid-template-columns:1fr;gap:10px;padding:12px}
  .diagram-wrap{aspect-ratio:auto;height:230px}
  .fold-step.final .diagram-wrap{height:200px}
  .check-grid{grid-template-columns:1fr}
  .check-grid .plate{max-width:320px}
  .mini-doctor dl{grid-template-columns:1fr}
  .plane-grid{grid-template-columns:repeat(2,minmax(0,1fr));gap:10px}
  .plane-grid.compact,.shelf .plane-grid{grid-template-columns:repeat(2,minmax(0,1fr))}
  .plane-card a{padding:10px}
  .pc-name{font-size:16.5px}
  .footer-links{grid-template-columns:1fr 1fr}
  .pager a{font-size:16px}
}