:root{
    --blue:#2f5aa0; --blue-d:#244a86;
    --orange:#d9602b; --orange-d:#c04e1d; --navy:#22426a; --navy-d:#122540;
    --ink:#111f38; --slate:#5a6785; --muted:#8792ab;
    --line:#e6e9f2; --soft:#f4f6fb; --tint:#e9eef8; --tint-b:#d3ddee; --green:#12894f;
  }
  *{box-sizing:border-box}
  html{scroll-behavior:smooth}
  body{margin:0;color:var(--ink);line-height:1.6;background:#fff;font-family:'Inter',-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Arial,sans-serif;font-size:16px;-webkit-font-smoothing:antialiased}
  h1,h2,h3,h4{font-family:'Barlow Condensed',sans-serif;letter-spacing:-.005em;font-weight:700}
  .hub-hero h1,.help h2,.subscribe h2{font-family:'Bebas Neue',sans-serif;font-weight:400;letter-spacing:.01em;line-height:.98}
  .wrap{max-width:1120px;margin:0 auto;padding:0 24px}
  a{color:inherit;text-decoration:none}

  .btn{display:inline-flex;align-items:center;justify-content:center;gap:9px;background:var(--blue);color:#fff;font-weight:700;font-size:15.5px;padding:14px 26px;border-radius:12px;border:none;cursor:pointer;box-shadow:0 10px 24px rgba(47,90,160,.30);transition:transform .15s,box-shadow .15s}
  .btn:hover{transform:translateY(-2px);box-shadow:0 16px 32px rgba(47,90,160,.36)}

  .kicker{display:flex;align-items:center;gap:12px;font-family:'Space Mono',monospace;font-size:13px;letter-spacing:.18em;text-transform:uppercase;font-weight:700;color:var(--blue)}
  .kicker.center{justify-content:center}
  .kicker::before,.kicker::after{content:"";height:1.5px;width:26px;background:var(--blue);opacity:.55}
  .kicker.left::after{display:none}

  nav{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.9);backdrop-filter:blur(12px);border-bottom:1px solid var(--line)}
  nav .row{display:flex;align-items:center;justify-content:space-between;padding:13px 0;gap:20px}
  .brand{display:flex;align-items:center;gap:11px}
  .brand .mark{width:38px;height:38px;border-radius:11px;background:linear-gradient(135deg,#3a67ad,var(--navy));display:flex;align-items:center;justify-content:center;flex:none}
  .brand .mark svg{width:20px;height:20px;stroke:#fff;fill:none;stroke-width:2.4;stroke-linecap:round;stroke-linejoin:round}
  .brand .t b{font-family:'Barlow Condensed',sans-serif;font-weight:700;font-size:19px;letter-spacing:.02em;display:block;color:var(--ink);line-height:1.05}
  .brand .t span{font-family:'Space Mono',monospace;font-size:9px;font-weight:700;letter-spacing:.15em;text-transform:uppercase;color:var(--orange)}
  .nav-links{display:flex;align-items:center;gap:26px}
  .nav-links a.l{font-size:14.5px;font-weight:600;color:var(--slate)}
  .nav-links a.l:hover{color:var(--blue)}
  nav .btn{padding:10px 18px;font-size:14px}
  .nav-login{font-size:14.5px;font-weight:600;color:var(--ink)}
  .has-mega{position:relative;padding-bottom:4px}
  .has-mega .trigger{display:inline-flex;align-items:center;gap:6px;font-size:14.5px;font-weight:600;color:var(--slate);cursor:default;transition:color .15s}
  .has-mega:hover .trigger{color:var(--blue)}
  .has-mega .trigger .caret{width:12px;height:12px;stroke:currentColor;fill:none;stroke-width:2.4;stroke-linecap:round;stroke-linejoin:round;transition:transform .2s}
  .has-mega:hover .trigger .caret{transform:rotate(180deg)}
  .mega{position:absolute;top:calc(100% + 14px);right:0;background:#fff;border:1px solid var(--line);border-radius:18px;box-shadow:0 30px 70px rgba(20,40,80,.16);padding:14px;width:560px;max-width:calc(100vw - 40px);opacity:0;visibility:hidden;transform:translateY(8px);transition:opacity .18s,transform .18s;z-index:60}
  .has-mega:hover .mega{opacity:1;visibility:visible;transform:translateY(0)}
  .mega::before{content:"";position:absolute;top:-16px;left:0;right:0;height:16px}
  .mega-grid{display:grid;grid-template-columns:1fr 1fr;gap:6px}
  @media(max-width:600px){.mega-grid{grid-template-columns:1fr}}
  .mega-item{display:flex;gap:13px;padding:14px;border-radius:12px}
  .mega-item.on{cursor:pointer;transition:background .15s}
  .mega-item.on:hover{background:var(--soft)}
  .mega-item .mi{width:42px;height:42px;border-radius:11px;background:var(--tint);display:flex;align-items:center;justify-content:center;flex:none}
  .mega-item .mi svg{width:21px;height:21px;stroke:var(--blue);fill:none;stroke-width:2;stroke-linecap:round;stroke-linejoin:round}
  .mega-item .mt b{display:flex;align-items:center;gap:8px;font-family:'Barlow Condensed',sans-serif;font-size:15px;color:var(--ink)}
  .mega-item .mt p{margin:3px 0 0;font-size:12.5px;color:var(--muted);line-height:1.45}
  .mega-item.off{cursor:not-allowed}.mega-item.off .mi{background:#f0f2f7}.mega-item.off .mi svg{stroke:#b6bece}.mega-item.off .mt b{color:#aab2c2}.mega-item.off .mt p{color:#c2c8d4}
  .soon{font-family:'Space Mono',monospace;font-size:9px;font-weight:700;letter-spacing:.06em;text-transform:uppercase;color:#98a1b3;background:#eef0f5;border:1px solid #e2e5ee;padding:2px 7px;border-radius:999px}
  @media(max-width:980px){.nav-links a.l,.nav-login,.has-mega{display:none}}

  /* ===== HERO ===== */
  .hub-hero{background:var(--soft);position:relative;overflow:hidden;padding:66px 0 48px;text-align:center;border-bottom:1px solid var(--line)}
  .hub-hero::before{content:"";position:absolute;inset:0;background-image:linear-gradient(rgba(34,66,106,.055) 1px,transparent 1px),linear-gradient(90deg,rgba(34,66,106,.055) 1px,transparent 1px);background-size:36px 36px;-webkit-mask-image:radial-gradient(120% 100% at 50% 0%,#000 40%,transparent 78%);mask-image:radial-gradient(120% 100% at 50% 0%,#000 40%,transparent 78%)}
  .hub-hero .wrap{position:relative;z-index:2;max-width:760px}
  .hub-hero .kicker{justify-content:center}
  .hub-hero h1{font-size:clamp(38px,5.4vw,62px);line-height:1.03;margin:20px 0 18px;color:var(--ink)}
  .hub-hero p{font-size:clamp(16px,1.9vw,20px);color:var(--slate);line-height:1.6;max-width:640px;margin:0 auto}
  .hub-hero .cta{margin-top:30px}
  .hub-meta{display:flex;align-items:center;justify-content:center;gap:12px;flex-wrap:wrap;margin-top:24px;font-family:'Space Mono',monospace;font-size:12.5px;color:var(--muted);text-transform:uppercase;letter-spacing:.05em}
  .hub-meta .dot{width:4px;height:4px;border-radius:50%;background:var(--tint-b)}
  /* index chapitres */
  .chap-nav{display:flex;flex-wrap:wrap;justify-content:center;gap:10px;margin-top:30px}
  .chap-nav a{font-size:13.5px;font-weight:600;color:var(--slate);background:#fff;border:1px solid var(--line);padding:8px 15px;border-radius:999px;transition:all .15s}
  .chap-nav a:hover{border-color:var(--blue);color:var(--blue)}
  .chap-nav a b{color:var(--blue);font-family:'Space Mono',monospace;margin-right:6px}

  /* ===== CHAPITRE ===== */
  .chapter{padding:58px 0;border-bottom:1px solid var(--line);scroll-margin-top:74px}
  .chapter.alt{background:var(--soft)}
  .chap-head{display:grid;grid-template-columns:1fr auto;gap:28px;align-items:end;margin-bottom:30px}
  @media(max-width:720px){.chap-head{grid-template-columns:1fr;gap:14px}}
  .chap-num{font-family:'Space Mono',monospace;font-size:13px;color:var(--blue);letter-spacing:.14em;text-transform:uppercase;font-weight:700}
  .chap-head h2{font-size:clamp(25px,3vw,34px);line-height:1.12;margin:8px 0 10px;color:var(--ink)}
  .chap-head .desc{color:var(--slate);font-size:16.5px;line-height:1.6;max-width:600px;margin:0}
  .chap-head .side{display:flex;flex-direction:column;align-items:flex-end;gap:12px;white-space:nowrap}
  @media(max-width:720px){.chap-head .side{align-items:flex-start}}
  .chap-head .count{font-family:'Space Mono',monospace;font-size:12px;color:var(--muted);text-transform:uppercase;letter-spacing:.06em}
  .chap-head .start{display:inline-flex;align-items:center;gap:7px;font-weight:700;font-size:14.5px;color:var(--blue)}
  .chap-head .start svg{width:16px;height:16px;stroke:currentColor;fill:none;stroke-width:2.4;stroke-linecap:round;stroke-linejoin:round;transition:transform .15s}
  .chap-head .start:hover svg{transform:translateX(4px)}

  .res-grid{display:grid;grid-template-columns:1fr 1fr;gap:14px}
  @media(max-width:720px){.res-grid{grid-template-columns:1fr}}
  .res{display:flex;justify-content:space-between;gap:14px;align-items:flex-start;background:#fff;border:1px solid var(--line);border-radius:14px;padding:18px 20px;transition:transform .15s,box-shadow .15s,border-color .15s}
  .res:hover{transform:translateY(-2px);box-shadow:0 14px 32px rgba(20,40,80,.09);border-color:var(--tint-b)}
  .res .b{min-width:0}
  .res .tt{display:flex;align-items:center;gap:8px;font-family:'Barlow Condensed',sans-serif;font-weight:600;font-size:16.5px;color:var(--ink);line-height:1.3}
  .res:hover .tt{color:var(--blue)}
  .res .tt .ar{color:var(--muted);font-size:14px}
  .res p{color:var(--slate);font-size:13.5px;line-height:1.5;margin:6px 0 0}
  .lvl{flex:none;font-family:'Space Mono',monospace;font-size:9.5px;font-weight:700;text-transform:uppercase;letter-spacing:.05em;padding:4px 9px;border-radius:999px;margin-top:2px}
  .lvl.deb{background:#eaf7ef;color:var(--green)}
  .lvl.int{background:var(--tint);color:var(--blue)}
  .lvl.adv{background:#fdeee4;color:var(--orange)}

  /* ===== HELP CTA ===== */
  .help{background:linear-gradient(135deg,var(--navy),var(--navy-d));position:relative;overflow:hidden;color:#fff;text-align:center}
  .help::before{content:"";position:absolute;inset:0;background-image:linear-gradient(rgba(255,255,255,.06) 1px,transparent 1px),linear-gradient(90deg,rgba(255,255,255,.06) 1px,transparent 1px);background-size:36px 36px}
  .help .wrap{position:relative;z-index:2;max-width:620px;padding:64px 24px}
  .help .kicker{justify-content:center;color:#f0a878}
  .help .kicker::before,.help .kicker::after{background:#f0a878}
  .help h2{color:#fff;font-size:clamp(26px,3.4vw,40px);margin:14px 0 12px}
  .help p{color:#cdd8ea;font-size:17px;margin:0 auto 26px;max-width:500px}
  .help .btn.white{background:#fff;color:var(--navy);box-shadow:0 12px 28px rgba(0,0,0,.2)}

  /* ===== NEWSLETTER ===== */
  .subscribe{background:#0e1728;color:#fff;padding:56px 0}
  .subscribe .wrap{text-align:center;max-width:560px}
  .subscribe .kicker{justify-content:center;color:#f0a878}
  .subscribe .kicker::before,.subscribe .kicker::after{background:#f0a878}
  .subscribe h2{font-size:clamp(24px,3vw,32px);margin:10px 0 10px}
  .subscribe p{color:#a9b6cf;font-size:16px;margin:0 auto 22px;max-width:460px}
  .subform{display:flex;gap:10px;max-width:440px;margin:0 auto;flex-wrap:wrap}
  .subform input{flex:1;min-width:200px;padding:14px 16px;border:none;border-radius:11px;font-size:15px;font-family:inherit}
  .subnote{font-family:'Space Mono',monospace;font-size:11.5px;color:#697389;margin-top:12px}
  .submsg{display:none;margin-top:12px;font-size:14px}
  .submsg.ok{display:block;color:#7fe3b8}.submsg.err{display:block;color:#f3a9a0}

  footer{background:#0b1220;color:#8793a8;padding:40px 0;font-size:14px}
  footer .row{display:flex;justify-content:space-between;align-items:center;gap:20px;flex-wrap:wrap}
  footer .brand .t b{color:#fff} footer .brand .t span{color:var(--orange)}
  footer a{color:#8793a8} footer a:hover{color:#fff}