:root{
  --paper:#F4F6F5; --panel:#FFFFFF; --ink:#142633; --muted:#556670; --line:#D8DFE0;
  --sea:#1C5D8C; --sea-dark:#154A70; --sea-soft:#E3EEF6; --sand:#F3EEE4; --ok:#2F6B5C; --err:#A33A2B;
  --serif:"Newsreader",Georgia,"Times New Roman",serif;
  --sans:"IBM Plex Sans",system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--paper);color:var(--ink);font-family:var(--sans);font-size:17px;line-height:1.6}
a{color:var(--sea)}
img{max-width:100%;height:auto;display:block}
.wrap{max-width:1080px;margin:0 auto;padding:0 20px}
h1,h2,h3{font-family:var(--serif);font-weight:600;line-height:1.15;margin:0 0 .5em;letter-spacing:-.01em}
h1{font-size:clamp(34px,5vw,54px)}
h2{font-size:clamp(26px,3.4vw,36px)}
h3{font-size:21px}
p{margin:0 0 1em}
.eyebrow{font-size:13px;letter-spacing:.12em;text-transform:uppercase;color:var(--muted);margin-bottom:12px}
.lede{font-size:clamp(18px,2vw,21px);color:#2E4250;max-width:40em}
.muted{color:var(--muted)}

/* header */
.site-head{border-bottom:1px solid var(--line);background:var(--panel)}
.site-head .wrap{display:flex;align-items:center;justify-content:space-between;gap:16px;min-height:64px}
.brand{font-family:var(--serif);font-weight:600;font-size:21px;color:var(--ink);text-decoration:none}
.brand span{color:var(--sea)}
.nav{display:flex;gap:20px;font-size:15px}
.nav a{text-decoration:none;color:var(--ink)}
.nav a:hover{color:var(--sea)}
@media (max-width:560px){.nav a.hide-sm{display:none}}

/* buttons */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;padding:13px 22px;border-radius:8px;font-weight:600;font-size:16px;text-decoration:none;border:2px solid var(--sea);cursor:pointer;font-family:var(--sans)}
.btn-primary{background:var(--sea);color:#fff}
.btn-primary:hover{background:var(--sea-dark);border-color:var(--sea-dark)}
.btn-ghost{background:transparent;color:var(--sea)}
.btn-ghost:hover{background:var(--sea-soft)}
.btns{display:flex;flex-wrap:wrap;gap:12px;margin:24px 0 10px}
.small{font-size:14px}

/* sections */
section{padding:64px 0}
section.alt{background:var(--panel);border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
section.sand{background:var(--sand)}

/* hero */
.hero{display:grid;grid-template-columns:minmax(0,1.3fr) minmax(0,.7fr);gap:48px;align-items:center;padding:56px 0 64px}
.hero .cover{box-shadow:0 18px 40px rgba(20,38,51,.25),0 2px 6px rgba(20,38,51,.2);border-radius:3px;max-width:340px;margin-left:auto}
@media (max-width:820px){.hero{grid-template-columns:1fr;gap:32px;padding-top:36px}.hero .cover{margin:0 auto;max-width:260px;order:-1}}
.facts{display:flex;flex-wrap:wrap;gap:8px 18px;font-size:14px;color:var(--muted);margin-top:14px;padding:0;list-style:none}
.facts li::before{content:"✓ ";color:var(--ok);font-weight:600}

/* questions */
.qgrid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px;margin-top:28px;padding:0;list-style:none}
.qgrid li{background:var(--paper);border:1px solid var(--line);border-radius:10px;padding:16px 18px;font-size:16px}
.qgrid b{display:block;font-family:var(--serif);font-size:19px;font-weight:600;margin-bottom:2px}
@media (max-width:700px){.qgrid{grid-template-columns:1fr}}

/* three */
.three{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:24px;margin-top:28px}
.three div{border-top:3px solid var(--sea);padding-top:14px}
@media (max-width:820px){.three{grid-template-columns:1fr}}

/* contents */
.toc{columns:2;column-gap:40px;margin:28px 0 0;padding:0;list-style:none}
.toc li{break-inside:avoid;padding:10px 0;border-bottom:1px solid var(--line)}
.toc b{font-weight:600}
.toc span{display:block;font-size:15px;color:var(--muted)}
@media (max-width:760px){.toc{columns:1}}

/* calculator promo */
.calc-cta{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:40px;align-items:center}
.figs{display:grid;grid-template-columns:1fr 1fr;gap:12px}
.figs div{background:var(--panel);border:1px solid var(--line);border-radius:10px;padding:14px 16px}
.figs span{display:block;font-size:13px;color:var(--muted)}
.figs b{font-family:"IBM Plex Mono",ui-monospace,monospace;font-size:22px;color:var(--sea)}
@media (max-width:820px){.calc-cta{grid-template-columns:1fr}}

/* signup */
.signup{max-width:640px;margin:0 auto;text-align:center}
.signup form{margin-top:18px}
.signup .inline{display:flex;gap:10px}
.signup input[type=email]{flex:1;min-width:0;font:inherit;padding:12px 14px;border:1px solid var(--line);border-radius:8px;background:#fff;color:var(--ink)}
.signup input[type=email]:focus{outline:2px solid var(--sea);outline-offset:1px}
.consent{display:flex;gap:10px;align-items:flex-start;text-align:left;font-size:14px;color:var(--muted);margin-top:12px}
.consent input{margin-top:4px}
.msg{min-height:1.4em;font-size:15px;margin:10px 0 0}
.msg.ok{color:var(--ok)} .msg.err{color:var(--err)}
@media (max-width:520px){.signup .inline{flex-direction:column}}

/* faq */
.faq{max-width:760px}
.faq details{border-bottom:1px solid var(--line);padding:16px 0}
.faq summary{cursor:pointer;font-weight:600;font-size:18px;list-style:none;display:flex;justify-content:space-between;gap:16px}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:"+";color:var(--sea);font-weight:400;font-size:22px;line-height:1}
.faq details[open] summary::after{content:"–"}
.faq details p{margin:10px 0 0;color:#2E4250}

/* series */
.series{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:18px;margin-top:28px}
.card{background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:22px;display:flex;flex-direction:column;gap:8px}
.card.live{border-color:var(--sea);box-shadow:0 1px 0 var(--sea)}
.tag{align-self:flex-start;font-size:12px;letter-spacing:.06em;text-transform:uppercase;padding:3px 9px;border-radius:99px;background:var(--sea-soft);color:var(--sea);font-weight:600}
.tag.soon{background:#EEF0F0;color:var(--muted)}
.card a.more{margin-top:auto;font-weight:600;text-decoration:none}

/* footer */
.site-foot{padding:40px 0 56px;font-size:14px;color:var(--muted);border-top:1px solid var(--line)}
.site-foot .wrap{display:grid;gap:12px}
.site-foot nav{display:flex;flex-wrap:wrap;gap:18px}
.site-foot a{color:var(--muted)}

/* prose pages */
.prose{max-width:720px;padding:48px 0 64px}
.prose h2{font-size:24px;margin-top:1.6em}

/* articles */
.crumbs{font-size:14px;color:var(--muted);padding-top:28px}
.crumbs a{color:var(--muted)}
.article{max-width:720px;padding:12px 0 48px}
.article .meta{font-size:14px;color:var(--muted);margin:-4px 0 28px}
.article h1{font-size:clamp(30px,4.4vw,44px)}
.article h2{font-size:25px;margin-top:1.8em}
.article ul,.article ol{padding-left:1.3em;margin:0 0 1em}
.article li{margin-bottom:.4em}
.article table{width:100%;border-collapse:collapse;margin:8px 0 22px;font-size:15px;display:block;overflow-x:auto}
.article th,.article td{text-align:left;padding:9px 10px;border-bottom:1px solid var(--line);vertical-align:top}
.article thead th{background:var(--sea-soft);font-weight:600}
.book-box{display:grid;grid-template-columns:90px 1fr;gap:18px;align-items:center;background:var(--panel);border:1px solid var(--sea);border-radius:12px;padding:18px;margin:36px 0 18px}
.book-box img{border-radius:2px;box-shadow:0 4px 12px rgba(20,38,51,.2)}
.book-box p{margin:0 0 10px}
.book-box .btns{margin:0}
.disclaimer{font-size:14px;color:var(--muted);border-top:1px solid var(--line);padding-top:14px}
.alist{list-style:none;padding:0;margin:28px 0 0;display:grid;gap:14px}
.alist a{display:block;background:var(--panel);border:1px solid var(--line);border-radius:10px;padding:18px 20px;text-decoration:none;color:var(--ink)}
.alist a:hover{border-color:var(--sea)}
.alist b{font-family:var(--serif);font-size:21px;font-weight:600;display:block;margin-bottom:4px}
.alist span{color:var(--muted);font-size:15px}
@media (max-width:520px){.book-box{grid-template-columns:1fr}.book-box img{width:80px}}

.brand{white-space:nowrap}
@media (max-width:560px){.site-head .wrap{flex-wrap:wrap;gap:4px 16px;padding-top:10px;padding-bottom:10px}.brand{font-size:19px}.nav{gap:16px;font-size:14px}.nav a{white-space:nowrap}}