:root{
  --navy:#14213D; --navy-2:#24314F; --ink:#2A2F3A; --soft:#4A4F5C; --muted:#6F7582;
  --gold:#9A6B12; --gold-2:#E0B454; --blue:#2F5D8A; --red:#A33A2B;
  --cream:#F7F5EF; --sand:#F4ECD9; --mist:#EEF1F5; --paper:#FFFDF8; --line:#E2DDD0;
  --radius:14px; --max:1120px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--cream);color:var(--ink);font-family:'Public Sans',Arial,sans-serif;font-size:17px;line-height:1.6;-webkit-font-smoothing:antialiased}
h1,h2,h3{font-family:'Libre Baskerville',Georgia,serif;color:var(--navy);line-height:1.2;margin:0 0 .5em}
h1{font-size:clamp(34px,5.2vw,60px)} h2{font-size:clamp(26px,3.4vw,40px)} h3{font-size:22px}
p{margin:0 0 1em} a{color:var(--blue)} img,video{max-width:100%}
.wrap{max-width:var(--max);margin:0 auto;padding:0 20px}
.eyebrow{font-size:13px;letter-spacing:.18em;text-transform:uppercase;color:var(--gold);font-weight:700;margin-bottom:10px}
.lead{font-size:clamp(18px,2vw,22px);color:var(--soft);max-width:760px}
/* en-tête */
.top{position:sticky;top:0;z-index:20;background:rgba(20,33,61,.97);backdrop-filter:blur(6px)}
.top .wrap{display:flex;align-items:center;justify-content:space-between;height:64px;gap:16px}
.logo{font-family:'Libre Baskerville',Georgia,serif;color:#F2EEE4;font-weight:700;font-size:20px;text-decoration:none;white-space:nowrap}
.logo span{color:var(--gold-2)}
.nav{display:flex;gap:22px;align-items:center}
.nav a{color:#C9CFDB;text-decoration:none;font-size:15px;font-weight:600}
.nav a:hover,.nav a.on{color:#F2EEE4}
.nav .btn-s{background:var(--gold-2);color:var(--navy);padding:8px 14px;border-radius:999px}
.burger{display:none;background:none;border:0;color:#F2EEE4;font-size:26px;cursor:pointer}
@media (max-width:820px){
  .burger{display:block}
  .nav{display:none;position:absolute;top:64px;left:0;right:0;background:var(--navy);flex-direction:column;align-items:flex-start;padding:16px 20px 22px;gap:14px}
  .nav.open{display:flex}
}
/* sections */
section{padding:72px 0}
.hero{background:var(--navy);color:#F2EEE4;padding:96px 0 88px}
.hero h1{color:#F2EEE4}.hero .lead{color:#C9CFDB}
.hero .eyebrow{color:var(--gold-2)}
.pills{display:flex;flex-wrap:wrap;gap:10px;margin-top:26px}
.pill{border:1.5px solid var(--gold-2);color:#F2EEE4;border-radius:999px;padding:8px 16px;font-size:14px;font-weight:600}
.pill.full{background:var(--gold-2);color:var(--navy)}
.dark{background:var(--navy);color:#C9CFDB}.dark h2,.dark h3{color:#F2EEE4}.dark .eyebrow{color:var(--gold-2)}
.mist{background:var(--mist)} .sand{background:var(--sand)}
.grid{display:grid;gap:18px}
.g2{grid-template-columns:repeat(2,1fr)} .g3{grid-template-columns:repeat(3,1fr)} .g4{grid-template-columns:repeat(4,1fr)}
@media (max-width:900px){.g3,.g4{grid-template-columns:repeat(2,1fr)}}
@media (max-width:600px){.g2,.g3,.g4{grid-template-columns:1fr}}
.card{background:var(--paper);border:1px solid var(--line);border-radius:var(--radius);padding:24px}
.card h3{margin-bottom:.4em}
.card.top-gold{border-top:5px solid var(--gold)} .card.top-blue{border-top:5px solid var(--blue)} .card.top-red{border-top:5px solid var(--red)}
.dark .card{background:var(--navy-2);border-color:#33415F;color:#C9CFDB}
.big{font-family:'Libre Baskerville',Georgia,serif;font-size:34px;color:var(--navy);font-weight:700;line-height:1.1;margin-bottom:6px}
.dark .big{color:var(--gold-2)}
.num{font-size:13px;font-weight:700;color:var(--gold);letter-spacing:.12em}
.btn{display:inline-block;background:var(--gold-2);color:var(--navy);font-weight:700;text-decoration:none;padding:13px 22px;border-radius:999px;border:0;cursor:pointer;font-size:16px}
.btn.ghost{background:transparent;border:1.5px solid currentColor;color:inherit}
.row{display:flex;gap:14px;flex-wrap:wrap;align-items:center}
.box{background:var(--paper);border-left:5px solid var(--gold);padding:16px 20px;border-radius:6px;margin:18px 0}
.box.blue{border-left-color:var(--blue);background:#FBFCFD}.box.red{border-left-color:var(--red);background:#FBF0EE}
table{width:100%;border-collapse:collapse;margin:14px 0 20px;font-size:15.5px;background:var(--paper)}
th{background:var(--navy);color:#F2EEE4;text-align:left;padding:10px 12px;font-weight:600}
td{padding:9px 12px;border-bottom:1px solid var(--line)} td.n,th.n{text-align:right;font-variant-numeric:tabular-nums}
.tbl{overflow-x:auto}
/* académie */
.lesson-list a{display:block;text-decoration:none;color:inherit;height:100%}
.lesson-list .card{height:100%;transition:transform .15s,box-shadow .15s}
.lesson-list .card:hover{transform:translateY(-2px);box-shadow:0 8px 24px rgba(20,33,61,.08)}
.article{max-width:780px}
.article h2{margin-top:1.4em;font-size:28px}
.article ul,.article ol{padding-left:22px} .article li{margin-bottom:6px}
.formula{font-family:'Libre Baskerville',Georgia,serif;font-size:21px;color:var(--navy);background:var(--paper);border:1px solid var(--line);border-radius:10px;padding:16px 20px;margin:16px 0;text-align:center}
.calc{background:var(--paper);border:1px solid var(--line);border-radius:var(--radius);padding:22px;margin:22px 0}
.calc h3{font-family:'Public Sans',Arial,sans-serif;font-size:18px}
.calc label{display:block;font-size:14px;font-weight:600;color:var(--soft);margin:10px 0 4px}
.calc input{width:100%;padding:11px 12px;border:1px solid #CFC8B6;border-radius:8px;font-size:17px;font-family:inherit;background:#fff}
.calc .res{margin-top:16px;background:var(--sand);border-radius:10px;padding:14px 16px;font-size:18px;color:var(--navy)}
.calc .res b{font-size:24px}
.crumbs{font-size:14px;color:var(--muted);margin-bottom:14px}.crumbs a{color:var(--muted)}
.pager{display:flex;justify-content:space-between;gap:12px;margin-top:40px;flex-wrap:wrap}
/* fondateurs */
.video{background:#000;border-radius:var(--radius);overflow:hidden;aspect-ratio:16/9}
.video video{width:100%;height:100%;display:block}
.chap{display:grid;grid-template-columns:1.2fr 1fr;gap:24px;align-items:center;padding:28px 0;border-top:1px solid var(--line)}
@media (max-width:820px){.chap{grid-template-columns:1fr}}
.dl a{display:inline-block;margin:6px 10px 0 0;font-weight:600;font-size:15px}
/* pied */
footer{background:var(--navy);color:#9AA3B5;padding:44px 0;font-size:14px}
footer a{color:#C9CFDB}
footer .legal{margin-top:18px;font-size:13px;color:#8791A3;max-width:880px}