/* The Sky Ledger — daytime sky, livery red, navy ink. Layout: airline-livery header, cinematic sky hero, flight-strip ledger as the signature element. */
:root{
  --bg:#f5f8fc; --panel:#ffffff; --ink:#0e2642; --muted:#4a5d72; --line:#d6e2ee;
  --red:#d92430; --red-ink:#b81c27; --blue:#1767c4; --navy:#0e2642; --tint:#e8f1fb;
  --display:"Poppins", "Arial Black", Arial, sans-serif;
  --body:"Libre Franklin", "Helvetica Neue", Arial, sans-serif;
  --mono:"JetBrains Mono", ui-monospace, Menlo, Consolas, monospace;
  --measure:68ch; --radius:6px;
}
@media (prefers-color-scheme: dark){:root:not([data-theme="light"]){
  --bg:#0a1626; --panel:#10223a; --ink:#e8f0f8; --muted:#9fb3c8; --line:#22384f;
  --red:#f0444e; --red-ink:#ff6b73; --blue:#62acf2; --tint:#13294a; color-scheme:dark}}
:root[data-theme="dark"]{
  --bg:#0a1626; --panel:#10223a; --ink:#e8f0f8; --muted:#9fb3c8; --line:#22384f;
  --red:#f0444e; --red-ink:#ff6b73; --blue:#62acf2; --tint:#13294a; color-scheme:dark}

*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{background:var(--bg);color:var(--ink);font-family:var(--body);font-size:1.04rem;line-height:1.65}
a{color:inherit}
:focus-visible{outline:3px solid var(--blue);outline-offset:3px}
img{max-width:100%;display:block}
.wrap{max-width:1180px;margin:0 auto;padding-inline:clamp(16px,4vw,44px)}
.skip{position:absolute;left:-9999px}.skip:focus{left:16px;top:16px;background:var(--panel);padding:8px 12px;z-index:99}
.eyebrow{font-family:var(--mono);font-size:.74rem;letter-spacing:.14em;text-transform:uppercase;color:var(--red-ink);font-weight:500}
h1,h2,h3{font-family:var(--display);line-height:1.08;margin:0;text-wrap:balance}
h2{font-size:clamp(1.8rem,4.2vw,2.7rem);font-weight:700;letter-spacing:-.01em;margin-top:8px}
p{margin:0 0 1em}

/* Header with livery cheatline */
.site-head{position:sticky;top:env(safe-area-inset-top,0px);z-index:30;background:var(--panel);border-bottom:1px solid var(--line)}
.site-head::after{content:"";display:block;height:4px;background:linear-gradient(90deg,var(--red) 0 78%,var(--navy) 78% 100%)}
.site-head .wrap{display:flex;align-items:center;justify-content:space-between;gap:12px 24px;padding-block:10px;flex-wrap:wrap}
.brand{display:flex;align-items:center;gap:10px;text-decoration:none;font-family:var(--display);font-weight:700;font-size:1.02rem;letter-spacing:.04em;text-transform:uppercase}
.brand img{width:38px;height:38px}
.nav{display:flex;align-items:center;gap:4px 20px;flex-wrap:wrap}
.nav a{font-family:var(--display);font-weight:600;font-size:.86rem;text-decoration:none;color:var(--muted);padding:6px 0;border-bottom:2px solid transparent}
.nav a:hover{color:var(--ink)}
.nav a[aria-current="page"]{color:var(--ink);border-bottom-color:var(--red)}
.btn{display:inline-flex;align-items:center;gap:8px;font-family:var(--display);font-weight:600;font-size:.9rem;text-decoration:none;padding:11px 18px;border-radius:var(--radius);border:2px solid currentColor;background:none;color:var(--ink);cursor:pointer}
.btn.red{background:var(--red);border-color:var(--red);color:#fff}
.btn.red:hover{background:var(--red-ink);border-color:var(--red-ink)}
.btn.light{color:#fff;border-color:rgba(255,255,255,.8)}
.btn.light:hover{background:rgba(255,255,255,.12)}
.nav .btn{padding:7px 14px;font-size:.82rem;color:#fff}

/* Hero */
.hero{position:relative;color:#fff;background:#1a6fcc url("hero-sky.jpg") center/cover no-repeat;overflow:hidden}
.hero::before{content:"";position:absolute;inset:0;background:linear-gradient(90deg,rgba(10,30,58,.78) 0%,rgba(10,30,58,.45) 50%,rgba(10,30,58,0) 78%)}
.hero .wrap{position:relative;padding-block:clamp(56px,10vw,120px) clamp(80px,12vw,150px)}
.hero h1{font-size:clamp(2.4rem,6.6vw,4.8rem);font-weight:800;text-transform:uppercase;letter-spacing:-.01em;max-width:13ch}
.hero h1 span{display:block;color:#fff;background:var(--red);padding:0 .2em;width:fit-content;margin-top:.12em}
.hero p{font-size:clamp(1.05rem,2vw,1.25rem);max-width:44ch;margin:22px 0 28px;color:#eaf2fb}
.hero .eyebrow{color:#ffd9dc}
.actions{display:flex;flex-wrap:wrap;gap:12px}
.page-hero{background:var(--tint);border-bottom:1px solid var(--line)}
.page-hero .wrap{padding-block:clamp(40px,7vw,72px) clamp(32px,5vw,52px)}
.page-hero h1{font-size:clamp(2.1rem,5vw,3.4rem);font-weight:800;text-transform:uppercase;margin-top:8px}
.page-hero p{max-width:60ch;color:var(--muted);font-size:1.1rem;margin:16px 0 0}

section{padding-block:clamp(52px,8vw,88px)}
section + section{border-top:1px solid var(--line)}
.head{display:flex;flex-wrap:wrap;align-items:end;justify-content:space-between;gap:12px 24px;margin-bottom:28px}
.lede{color:var(--muted);font-size:1.12rem;max-width:58ch}

/* Formula strip: the five-step story shape */
.formula{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:0;border:2px solid var(--ink);border-radius:var(--radius);overflow:hidden;counter-reset:f}
.formula li{padding:18px 16px;border-right:1px solid var(--line);background:var(--panel);counter-increment:f;min-width:0}
.formula li:last-child{border-right:0}
.formula li::before{content:"0" counter(f);display:block;font-family:var(--mono);font-size:.72rem;color:var(--red-ink);margin-bottom:6px}
.formula b{display:block;font-family:var(--display);font-size:1rem;margin-bottom:4px}
.formula span{font-size:.9rem;color:var(--muted)}
@media (max-width:820px){.formula{grid-template-columns:minmax(0,1fr)}.formula li{border-right:0;border-bottom:1px solid var(--line)}}

/* Flight-strip ledger (signature) */
.ledger{display:grid;gap:12px}
.strip{background:var(--panel);border:1px solid var(--line);border-left:10px solid var(--blue);border-radius:4px;min-width:0}
.strip.flag{border-left-color:var(--red)}
.strip summary{list-style:none;cursor:pointer;display:grid;grid-template-columns:minmax(150px,1.1fr) minmax(0,2.4fr) auto;gap:6px 22px;align-items:center;padding:16px 18px}
.strip summary::-webkit-details-marker{display:none}
.strip .ac{font-family:var(--mono);font-weight:500;font-size:.95rem;letter-spacing:.02em}
.strip .ac small{display:block;font-size:.7rem;color:var(--muted);letter-spacing:.1em;text-transform:uppercase;margin-bottom:2px}
.strip .t{font-family:var(--display);font-weight:700;font-size:1.12rem;line-height:1.2}
.strip .q{display:block;font-family:var(--body);font-weight:400;font-size:.95rem;color:var(--muted);margin-top:4px}
.status{font-family:var(--mono);font-size:.72rem;letter-spacing:.08em;text-transform:uppercase;padding:5px 9px;border:1.5px solid currentColor;border-radius:3px;color:var(--blue);white-space:nowrap}
.status::after{content:" +";}
details[open] .status::after{content:" −"}
.strip .more{padding:0 18px 18px;border-top:1px dashed var(--line);margin:0 18px;padding-inline:0}
.strip .more p{margin:14px 0 0;max-width:var(--measure)}
.strip dl{display:grid;grid-template-columns:auto minmax(0,1fr);gap:6px 16px;margin:14px 0 0;font-size:.95rem}
.strip dt{font-family:var(--mono);font-size:.72rem;letter-spacing:.08em;text-transform:uppercase;color:var(--muted);padding-top:3px}
.strip dd{margin:0}
@media (max-width:720px){.strip summary{grid-template-columns:minmax(0,1fr)}.status{justify-self:start}}
.note{font-size:.9rem;color:var(--muted);margin-top:14px}

/* Cards */
.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:20px}
.card{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);overflow:hidden;display:flex;flex-direction:column;text-decoration:none;min-width:0;transition:border-color .15s,transform .15s}
.card:hover{border-color:var(--blue);transform:translateY(-2px)}
.card .img{aspect-ratio:16/9;background:#1a6fcc url("hero-sky.jpg") right/cover;position:relative}
.card .img b{position:absolute;left:14px;bottom:12px;font-family:var(--display);font-weight:800;font-size:1.7rem;color:#fff;text-shadow:0 2px 12px rgba(10,30,58,.5)}
.card .body{padding:18px;display:flex;flex-direction:column;gap:8px;flex:1}
.meta{display:flex;flex-wrap:wrap;gap:4px 12px;font-family:var(--mono);font-size:.72rem;letter-spacing:.06em;text-transform:uppercase;color:var(--muted)}
.meta .tag{color:var(--red-ink);font-weight:500}
.card h3{font-size:1.25rem;font-weight:700}
.card p{color:var(--muted);font-size:.96rem;margin:0}

/* Two column text blocks */
.two{display:grid;grid-template-columns:minmax(0,.85fr) minmax(0,1.5fr);gap:clamp(24px,5vw,64px)}
@media (max-width:860px){.two{grid-template-columns:minmax(0,1fr)}}
.prose{max-width:var(--measure)}
.prose h2{font-size:clamp(1.5rem,3.2vw,2rem);margin:1.6em 0 .5em;scroll-margin-top:96px}
.prose h3{font-size:1.15rem;margin:1.4em 0 .4em}
.prose ul{padding-left:1.2em}.prose li{margin-bottom:.4em}
.prose a{color:var(--blue)}
.standards{display:grid;grid-template-columns:repeat(auto-fit,minmax(230px,1fr));gap:18px}
.std{background:var(--panel);border:1px solid var(--line);border-top:4px solid var(--red);border-radius:var(--radius);padding:20px;min-width:0}
.std h3{font-size:1.08rem;margin-bottom:6px}
.std p{margin:0;color:var(--muted);font-size:.96rem}
.steps{list-style:none;margin:0;padding:0;counter-reset:s}
.steps li{display:grid;grid-template-columns:3.4rem minmax(0,1fr);gap:2px 16px;padding:18px 0;border-top:1px solid var(--line);counter-increment:s}
.steps li:last-child{border-bottom:1px solid var(--line)}
.steps li::before{content:counter(s,decimal-leading-zero);font-family:var(--display);font-weight:800;font-size:1.5rem;color:var(--red);grid-row:span 2;line-height:1}
.steps h3{font-size:1.06rem}
.steps p{margin:0;color:var(--muted)}

/* Call to action band */
.band{background:var(--navy);color:#fff;position:relative;overflow:hidden}
.band::before{content:"";position:absolute;left:-5%;right:-5%;bottom:28px;height:14px;background:var(--red);transform:rotate(-2deg)}
.band .wrap{position:relative;padding-block:clamp(48px,7vw,72px) clamp(64px,8vw,90px);display:flex;flex-wrap:wrap;gap:20px 40px;align-items:center;justify-content:space-between}
.band h2{color:#fff;max-width:22ch}
.band p{color:#c8d6e6;max-width:52ch;margin:10px 0 0}

/* Article */
.progress{position:fixed;top:0;left:0;height:4px;width:0;background:var(--red);z-index:40}
.art-hero{position:relative;color:#fff;background:#1a6fcc url("hero-sky.jpg") center/cover}
.art-hero::before{content:"";position:absolute;inset:0;background:linear-gradient(0deg,rgba(10,30,58,.9),rgba(10,30,58,.35))}
.art-hero .wrap{position:relative;padding-block:clamp(56px,9vw,110px) clamp(36px,5vw,56px)}
.art-hero h1{font-size:clamp(2rem,5vw,3.4rem);font-weight:800;max-width:20ch;margin:12px 0 14px}
.art-hero .dek{font-size:1.18rem;max-width:56ch;color:#e3edf8;margin:0}
.art-hero .meta{color:#cfe0f2;margin-top:18px}
.art-hero .meta .tag{color:#fff;background:var(--red);padding:2px 8px;border-radius:3px}
.back{display:inline-block;font-family:var(--mono);font-size:.78rem;letter-spacing:.06em;text-transform:uppercase;color:#cfe0f2;text-decoration:none}
.art-grid{display:grid;grid-template-columns:minmax(0,1fr) 280px;gap:clamp(28px,5vw,64px);align-items:start}
.toc{position:sticky;top:96px;background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);padding:18px}
.toc h2{font-size:.82rem;font-family:var(--mono);font-weight:500;letter-spacing:.12em;text-transform:uppercase;color:var(--muted);margin:0 0 10px}
.toc ol{list-style:none;margin:0;padding:0;display:grid;gap:2px}
.toc a{display:block;text-decoration:none;font-size:.92rem;color:var(--muted);padding:6px 10px;border-left:3px solid transparent}
.toc a.on{color:var(--ink);border-left-color:var(--red);background:var(--tint)}
.support{margin-top:18px;padding-top:16px;border-top:1px solid var(--line);font-size:.92rem;color:var(--muted)}
.support a{color:var(--blue)}
@media (max-width:960px){.art-grid{grid-template-columns:minmax(0,1fr)}.toc{position:static;order:-1}}
.record{background:var(--tint);border-left:5px solid var(--blue);padding:16px 20px;border-radius:4px;margin:1.4em 0}
.record b{font-family:var(--mono);font-size:.74rem;letter-spacing:.1em;text-transform:uppercase;display:block;margin-bottom:6px;color:var(--blue)}
.record p:last-child{margin:0}
.sources ol{padding-left:1.3em}
.sources li{margin-bottom:.7em;overflow-wrap:anywhere}

.email{font-family:var(--display);font-weight:700;font-size:clamp(1.3rem,3.6vw,2rem);color:var(--red-ink);overflow-wrap:anywhere;user-select:all}
.email-row{display:flex;flex-wrap:wrap;align-items:center;gap:12px;margin:8px 0 14px}
.copied{font-family:var(--mono);font-size:.78rem;color:var(--blue)}

.site-foot{background:var(--panel);border-top:1px solid var(--line)}
.site-foot::before{content:"";display:block;height:4px;background:linear-gradient(90deg,var(--red) 0 78%,var(--navy) 78% 100%)}
.site-foot .wrap{display:grid;grid-template-columns:minmax(0,1.4fr) repeat(2,minmax(0,1fr));gap:28px;padding-block:40px 28px}
.site-foot h2{font-family:var(--mono);font-size:.74rem;font-weight:500;letter-spacing:.12em;text-transform:uppercase;color:var(--muted);margin:0 0 10px}
.site-foot ul{list-style:none;margin:0;padding:0;display:grid;gap:6px}
.site-foot a{text-decoration:none;color:var(--ink)}.site-foot a:hover{color:var(--red-ink)}
.site-foot .small{grid-column:1/-1;border-top:1px solid var(--line);padding-top:16px;font-family:var(--mono);font-size:.76rem;color:var(--muted);display:flex;flex-wrap:wrap;gap:8px 20px;justify-content:space-between}
@media (max-width:720px){.site-foot .wrap{grid-template-columns:minmax(0,1fr)}}
@media (prefers-reduced-motion:reduce){*{transition:none!important;scroll-behavior:auto!important}}