:root{
  --blue:#1A73E8; --blue-d:#1657c0; --ink:#202124; --grey:#5f6368; --grey2:#3c4043;
  --bg:#fff; --soft:#f4f8ff; --soft2:#e8f0fe; --line:#e3e8ee;
  --green:#188038; --green-s:#e6f4ea; --red:#d93025; --red-s:#fce8e6; --amber:#b06000; --amber-s:#fef7e0;
}
*{box-sizing:border-box} html{scroll-behavior:smooth;scroll-padding-top:72px} html,body{margin:0}
body{ font-family:'Google Sans','Segoe UI',Roboto,system-ui,Arial,sans-serif; color:var(--ink); background:#fff; line-height:1.6; -webkit-font-smoothing:antialiased;}
a{color:var(--blue-d)}
.gbar{height:5px;background:linear-gradient(90deg,#EA4335 0 25%,#FBBC04 25% 50%,#34A853 50% 75%,#4285F4 75% 100%)}
.wrap{max-width:1120px;margin:0 auto;padding:0 24px}
img{max-width:100%;display:block;height:auto}

/* ---------- NAV (sticky) ---------- */
.topnav{position:sticky;top:0;z-index:40;background:rgba(255,255,255,.92);backdrop-filter:saturate(180%) blur(8px);border-bottom:1px solid var(--line)}
.topnav .row{display:flex;align-items:center;justify-content:space-between;padding-top:14px;padding-bottom:14px}
.brand{font-weight:700;font-size:16.5px;letter-spacing:-.2px}
.brand .dot{display:inline-block;width:9px;height:9px;background:var(--blue);border-radius:50%;margin-right:8px;vertical-align:middle}
.brand .logo{height:24px;width:24px;margin-right:8px;vertical-align:middle;position:relative;top:-1px}
.nav-cta{font-size:14px;font-weight:600;background:var(--blue);color:#fff;padding:9px 16px;border-radius:9px;text-decoration:none}
.nav-cta:hover{background:var(--blue-d)}

/* ---------- buttons ---------- */
.btn{display:inline-block;text-align:center;background:var(--blue);color:#fff;border:0;border-radius:10px;padding:14px 24px;font-size:16px;font-weight:600;font-family:inherit;cursor:pointer;text-decoration:none;transition:background .15s}
.btn:hover{background:var(--blue-d)}
.btn-ghost{display:inline-block;text-align:center;background:#fff;color:var(--blue-d);border:1px solid #c9d6ec;border-radius:10px;padding:13px 22px;font-size:15px;font-weight:600;text-decoration:none}
.btn-ghost:hover{background:var(--soft)}

/* ---------- HERO ---------- */
.hero{display:grid;grid-template-columns:1.08fr .92fr;gap:46px;align-items:center;padding-top:54px;padding-bottom:50px}
.kicker{display:inline-block;background:var(--soft2);color:var(--blue-d);font-size:12px;font-weight:700;letter-spacing:.06em;text-transform:uppercase;padding:6px 12px;border-radius:999px}
.hero h1{font-size:43px;line-height:1.08;margin:18px 0 16px;letter-spacing:-.7px}
.hero .lead{font-size:18.5px;color:var(--grey2);margin:0 0 22px}
ul.benefits{list-style:none;padding:0;margin:0 0 26px}
ul.benefits li{position:relative;padding:7px 0 7px 30px;font-size:15.5px}
ul.benefits li::before{content:"";position:absolute;left:0;top:11px;width:17px;height:17px;border-radius:50%;
  background:var(--soft2) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='%231A73E8'%3E%3Cpath d='M9 16.2 4.8 12l-1.4 1.4L9 19 21 7l-1.4-1.4z'/%3E%3C/svg%3E") center/14px no-repeat}
.cta-row{display:flex;gap:12px;flex-wrap:wrap;align-items:center}
.cover-frame{border-radius:14px;overflow:hidden;border:1px solid var(--line);box-shadow:0 24px 60px rgba(26,58,95,.18);transform:rotate(-1.4deg);transition:transform .25s}
.cover-frame:hover{transform:rotate(0)}
.cover-wrap{position:relative}
.cover-badge{position:absolute;right:-10px;top:-14px;background:var(--ink);color:#fff;font-size:12px;font-weight:700;padding:8px 13px;border-radius:999px;box-shadow:0 6px 18px rgba(0,0,0,.2);transform:rotate(3deg)}

/* ---------- trust bar ---------- */
.trustbar{border-top:1px solid var(--line);border-bottom:1px solid var(--line);background:var(--soft)}
.trustbar .row{display:flex;flex-wrap:wrap;gap:10px 26px;align-items:center;justify-content:center;padding-top:16px;padding-bottom:16px;font-size:13.5px;color:var(--grey2);font-weight:600}
.trustbar .row span{display:inline-flex;align-items:center;gap:7px}
.trustbar b{color:var(--blue-d)}

/* ---------- bandeau stack (logos) ---------- */
.stackband{background:#fff;border-bottom:1px solid var(--line)}
.stackband .wrap{display:flex;align-items:flex-start;justify-content:center;gap:12px 30px;flex-wrap:wrap;padding:18px 22px}
.stackband .sl{font-size:11.5px;color:#9aa0a6;font-weight:700;text-transform:uppercase;letter-spacing:.06em;padding-top:3px}
.stackband .sgroups{display:flex;flex-wrap:wrap;gap:16px 30px;align-items:flex-start}
.stackband .sg{display:flex;flex-direction:column;gap:8px;position:relative}
.stackband .sg:not(:last-child)::after{content:"";position:absolute;right:-15px;top:2px;bottom:2px;width:1px;background:#eceff1}
.stackband .sgl{font-size:9.5px;font-weight:700;color:#bdc1c6;text-transform:uppercase;letter-spacing:.07em}
.stackband .sgi{display:flex;flex-wrap:wrap;gap:8px 16px}
.stackband .lg{display:inline-flex;align-items:center;gap:7px;font-size:14px;font-weight:600;color:#3c4043}
.stackband .lg svg{width:21px;height:21px;flex:0 0 auto}
.stackband .lg .lgimg{width:21px;height:21px;object-fit:contain;flex:0 0 auto}
@media(max-width:560px){.stackband .wrap{gap:12px 18px}.stackband .sgroups{gap:14px 20px}.stackband .sg:not(:last-child)::after{display:none}.stackband .lg{font-size:13px}.stackband .lg svg,.stackband .lg .lgimg{width:19px;height:19px}}

/* ---------- sections ---------- */
.sec{padding:62px 0}
.sec.alt{background:var(--soft)}
.eyebrow{display:block;text-align:center;color:var(--blue-d);font-size:12.5px;font-weight:700;letter-spacing:.08em;text-transform:uppercase;margin-bottom:8px}
.sec h2{font-size:31px;line-height:1.15;text-align:center;margin:0 auto 12px;max-width:760px;letter-spacing:-.5px}
.sec .sub{font-size:17px;color:var(--grey2);text-align:center;max-width:680px;margin:0 auto 38px}

/* problème : augmentation vs atrophie */
.vs{display:grid;grid-template-columns:1fr 1fr;gap:22px;max-width:920px;margin:0 auto}
.vs .col{border:1px solid var(--line);border-radius:16px;padding:24px;background:#fff}
.vs .col.up{border-top:4px solid var(--green)}
.vs .col.down{border-top:4px solid var(--red)}
.vs .tag{display:inline-block;font-size:12.5px;font-weight:700;padding:4px 11px;border-radius:999px;margin-bottom:10px}
.vs .up .tag{background:var(--green-s);color:var(--green)}
.vs .down .tag{background:var(--red-s);color:var(--red)}
.vs h3{margin:.1em 0 .4em;font-size:19px}
.vs p{margin:0;color:var(--grey2);font-size:15px}

/* cards : ce que contient le livre */
.cards{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}
.card2{border:1px solid var(--line);border-radius:16px;padding:22px;background:#fff;transition:box-shadow .2s,transform .2s}
.card2:hover{box-shadow:0 10px 30px rgba(32,33,36,.08);transform:translateY(-2px)}
.card2 .ic{width:42px;height:42px;border-radius:11px;background:var(--soft2);display:flex;align-items:center;justify-content:center;margin-bottom:13px}
.card2 .ic svg{width:23px;height:23px;fill:var(--blue-d)}
.card2 h3{margin:0 0 6px;font-size:17.5px}
.card2 p{margin:0;color:var(--grey2);font-size:14.5px}
.card2 .num{font-size:13px;font-weight:700;color:var(--blue-d)}

/* aperçu pages */
.previews{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}
.shot{border:1px solid var(--line);border-radius:12px;overflow:hidden;box-shadow:0 8px 24px rgba(32,33,36,.10)}
.shot img{width:100%}
.previews + .pcap{text-align:center;color:var(--grey);font-size:14px;margin-top:18px}

/* métriques */
.metrics{display:grid;grid-template-columns:repeat(5,1fr);gap:16px}
.metric{background:#fff;border:1px solid var(--line);border-radius:16px;padding:20px 16px;text-align:center}
.metric .num{font-size:30px;font-weight:800;color:var(--blue-d);letter-spacing:-.5px;line-height:1}
.metric .lbl{font-size:13px;color:var(--grey);margin-top:7px}

/* sources académiques */
.sources{display:grid;grid-template-columns:repeat(2,1fr);gap:18px;max-width:920px;margin:0 auto}
.srcc{border:1px solid var(--line);border-left:4px solid var(--blue);border-radius:12px;padding:18px 20px;background:#fff}
.srcc .st{font-size:13px;font-weight:700;color:var(--blue-d);text-transform:uppercase;letter-spacing:.04em}
.srcc p{margin:6px 0 0;font-size:14.5px;color:var(--grey2)}
.srcc b{color:var(--ink)}

/* auteur */
.author{display:grid;grid-template-columns:auto 1fr;gap:26px;align-items:center;max-width:880px;margin:0 auto;background:#fff;border:1px solid var(--line);border-radius:18px;padding:28px}
.avatar{width:104px;height:104px;border-radius:50%;background:linear-gradient(135deg,#1A73E8,#34A853);color:#fff;display:flex;align-items:center;justify-content:center;font-size:38px;font-weight:700;letter-spacing:1px}
.avatar.photo{width:132px;height:132px;border-radius:18px;background:none;padding:0;overflow:hidden;box-shadow:0 2px 10px rgba(60,64,67,.14)}
.avatar.photo img{width:100%;height:100%;object-fit:cover;display:block}
.author h3{margin:0 0 2px;font-size:21px}
.author .role{color:var(--grey);font-size:14px;margin:0 0 10px}
.author p{margin:0 0 12px;color:var(--grey2);font-size:15px}

/* FAQ */
.faq{max-width:780px;margin:0 auto}
.faq details{border:1px solid var(--line);border-radius:12px;padding:4px 18px;margin-bottom:12px;background:#fff}
.faq summary{cursor:pointer;font-weight:600;font-size:16px;padding:14px 0;list-style:none;display:flex;justify-content:space-between;align-items:center}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:"+";font-size:22px;color:var(--blue-d);font-weight:400}
.faq details[open] summary::after{content:"–"}
.faq details p{margin:0 0 16px;color:var(--grey2);font-size:15px}

/* ---------- form ---------- */
.formwrap{max-width:560px;margin:0 auto}
.card{background:#fff;border:1px solid var(--line);border-radius:18px;box-shadow:0 12px 40px rgba(32,33,36,.12);padding:26px}
.card h2{font-size:22px;margin:0 0 4px;text-align:left}
.card p.sub{margin:0 0 18px;color:var(--grey);font-size:14px;text-align:left}
.field{margin-bottom:13px}
.field label{display:block;font-size:13px;font-weight:600;margin-bottom:5px}
.field input,.field select{width:100%;padding:13px 12px;border:1px solid #cfd6de;border-radius:10px;font-size:16px;font-family:inherit;color:var(--ink);background:#fff}
.field input:focus,.field select:focus{outline:none;border-color:var(--blue);box-shadow:0 0 0 3px rgba(26,115,232,.15)}
.consent{display:flex;gap:9px;align-items:flex-start;font-size:12.5px;color:var(--grey);margin:6px 0 16px}
.consent input{margin-top:2px}
.hp{position:absolute;left:-9999px}
.err{background:var(--red-s);color:#c5221f;border-radius:10px;padding:10px 13px;font-size:13.5px;margin-bottom:14px}
.note{font-size:11.5px;color:#9aa0a6;text-align:center;margin-top:12px}
.proof{display:flex;flex-wrap:wrap;gap:8px;margin-top:14px}
.chip{background:#fff;border:1px solid var(--line);border-radius:999px;padding:6px 12px;font-size:12.5px;color:var(--grey2);font-weight:600}
.chip b{color:var(--blue-d)}

footer.ft{border-top:1px solid var(--line);padding:26px 0;color:var(--grey);font-size:13px;text-align:center}

/* merci */
.thanks{max-width:620px;margin:60px auto;text-align:center}
.thanks .big{font-size:30px;margin:14px 0 8px}
.tick{width:64px;height:64px;border-radius:50%;background:var(--soft2);display:inline-flex;align-items:center;justify-content:center}

/* BO */
.bo{padding:24px 0}
.kpis{display:grid;grid-template-columns:repeat(4,1fr);gap:14px;margin:18px 0}
.kpi{background:var(--soft);border:1px solid var(--line);border-radius:14px;padding:16px}
.kpi .n{font-size:30px;font-weight:700;color:var(--blue-d)}
.kpi .l{font-size:13px;color:var(--grey)}
table.leads{width:100%;border-collapse:collapse;font-size:13.5px;margin-top:10px}
table.leads th,table.leads td{border-bottom:1px solid var(--line);padding:9px 10px;text-align:left}
table.leads th{background:#f8fafd;color:var(--grey2);font-weight:600}
.src-tag{font-size:11px;font-weight:600;padding:2px 8px;border-radius:999px;background:var(--soft2);color:var(--blue-d)}

/* ---------- responsive ---------- */
@media(max-width:900px){
  .hero{grid-template-columns:1fr;gap:30px;padding-top:36px;padding-bottom:36px}
  .hero h1{font-size:33px}
  .cover-wrap{max-width:440px;margin:0 auto}
  .cards{grid-template-columns:1fr 1fr}
  .previews{grid-template-columns:1fr}
  .metrics{grid-template-columns:repeat(2,1fr)}
  .sources{grid-template-columns:1fr}
  .vs{grid-template-columns:1fr}
  .kpis{grid-template-columns:repeat(2,1fr)}
}
@media(max-width:560px){
  .hero h1{font-size:28px} .sec h2{font-size:25px}
  .cards{grid-template-columns:1fr}
  .author{grid-template-columns:1fr;text-align:center} .avatar{margin:0 auto}
}

/* ---- Mobile : CTA collante + perf ---- */
.mcta{display:none}
@media(max-width:760px){
  body{padding-bottom:74px}
  .nav-cta{display:none}
  .sec{padding-top:44px;padding-bottom:44px}
  .hero{padding-top:24px}
  .cover-wrap{max-width:360px}
  .formwrap .card{padding:20px}
  .mcta{display:block;position:fixed;left:0;right:0;bottom:0;z-index:60;background:var(--blue);color:#fff;
    text-align:center;font-weight:600;font-size:16px;padding:16px;text-decoration:none;
    box-shadow:0 -6px 20px rgba(0,0,0,.14)}
  .mcta:active{background:var(--blue-d)}
}