/* Site vitrine d'Arcalyse — base A (clair, sobre), accroche et galerie de B, pile des couches de C.
   Polices système, aucune ressource externe. Thème sombre selon prefers-color-scheme. */
:root{
  --bg:#f5f6fa;--bg2:#fff;--card:#fff;--ink:#1b1d29;--dim:#5b6072;--line:#dfe2ea;--line2:#c4c9d6;
  --pri:#3b5bdb;--pri-d:#2f4ac0;--pri-bg:#e8edff;--code:#1b1d29;--code-ink:#dfe3f0;
  --oa:#f0a35e;--sa:#5aa2e8;--la:#4fc3a1;--pa:#e8c84f;--epbs:#a98be0;
  --halo:.55;--shadow:0 24px 60px -24px rgba(30,40,90,.35);--r:12px;
  font-family:system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;color-scheme:light;
}
@media (prefers-color-scheme:dark){:root{
  --bg:#0e1016;--bg2:#141722;--card:#1a1e2c;--ink:#eef0f7;--dim:#a2a8bd;--line:#2a2f42;--line2:#3d4460;
  --pri:#6d8cff;--pri-d:#8aa2ff;--pri-bg:#1f2747;--code:#0a0c12;--code-ink:#c6cbe0;
  --halo:.38;--shadow:0 -10px 80px -20px rgba(90,162,232,.45);color-scheme:dark;
}}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--ink);line-height:1.55;overflow-x:hidden}
a{color:var(--pri)}img{max-width:100%;height:auto;display:block}
code{font-family:ui-monospace,Consolas,monospace;font-size:.92em}
.wrap{max-width:1160px;margin:0 auto;padding:0 24px}
.sr{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0)}
:focus-visible{outline:3px solid var(--pri);outline-offset:2px;border-radius:6px}

/* En-tête */
header{position:sticky;top:0;z-index:20;background:color-mix(in srgb,var(--bg2) 85%,transparent);backdrop-filter:blur(10px);border-bottom:1px solid var(--line)}
header .wrap{display:flex;align-items:center;gap:28px;height:62px}
.brand{display:flex;align-items:center;gap:10px;font-weight:700;font-size:20px;color:var(--ink);text-decoration:none}
header{transition:box-shadow .3s}header.scrolled{box-shadow:0 8px 28px -18px rgba(20,30,70,.45)}
nav{display:flex;gap:22px;flex:1}nav a{color:var(--dim);text-decoration:none;font-size:15px;position:relative;white-space:nowrap;transition:color .2s}nav a:hover,nav a[aria-current]{color:var(--ink)}
nav a::after{content:"";position:absolute;left:0;right:0;bottom:-5px;height:2px;border-radius:2px;background:var(--pri);transform:scaleX(0);transform-origin:left;transition:transform .25s ease}
nav a:hover::after,nav a[aria-current]::after{transform:scaleX(1)}
nav a.ext span[aria-hidden]{font-size:.8em;margin-left:3px;opacity:.65;display:inline-block;transition:transform .2s,opacity .2s}nav a.ext:hover span[aria-hidden]{opacity:1;transform:translate(1px,-1px)}
.langs{display:flex;align-items:center;gap:2px;margin-left:auto;font-size:13.5px;font-weight:600}
.langs>*{padding:4px 8px;border-radius:99px;color:var(--dim);text-decoration:none}.langs a:hover{color:var(--ink)}
.langs [aria-current]{background:var(--pri-bg);color:var(--ink)}

/* Boutons */
.btn{display:inline-flex;align-items:center;gap:8px;border-radius:99px;padding:11px 20px;font-weight:600;font-size:15px;text-decoration:none;border:1px solid var(--line);color:var(--ink);background:var(--card);cursor:pointer;font-family:inherit}
.btn{transition:transform .15s ease,box-shadow .2s ease,background .2s,border-color .2s}.btn:hover{border-color:var(--line2);transform:translateY(-1px);box-shadow:0 10px 22px -14px rgba(20,30,70,.45)}.btn:active{transform:translateY(0);box-shadow:none}
.btn-pri{background:var(--pri);border-color:var(--pri);color:#fff}.btn-pri:hover{background:var(--pri-d);border-color:var(--pri-d);box-shadow:0 12px 26px -12px var(--pri)}
@media (prefers-color-scheme:dark){.btn-pri{color:#0e1016}}
.btn-sm{padding:7px 14px;font-size:14px}

/* Accroche avec halo mouvant */
.hero{position:relative;text-align:center;padding:76px 0 0;overflow:hidden;isolation:isolate}
.halo{position:absolute;inset:-120px -10% auto;height:760px;z-index:-1;filter:blur(80px);opacity:var(--halo);pointer-events:none}
.halo i{position:absolute;width:42%;aspect-ratio:1;border-radius:50%;mix-blend-mode:normal}
.halo i:nth-child(1){background:var(--oa);left:4%;top:12%;animation:h1 13s ease-in-out infinite alternate}
.halo i:nth-child(2){background:var(--sa);left:28%;top:0;animation:h2 16s ease-in-out infinite alternate}
.halo i:nth-child(3){background:var(--la);left:50%;top:18%;animation:h3 14s ease-in-out infinite alternate}
.halo i:nth-child(4){background:var(--pa);left:66%;top:4%;width:34%;animation:h4 17s ease-in-out infinite alternate}
.halo i:nth-child(5){background:var(--epbs);left:38%;top:34%;width:30%;opacity:.7;animation:h5 19s ease-in-out infinite alternate}
@keyframes h1{to{transform:translate(32%,14%) scale(1.2)}}
@keyframes h2{to{transform:translate(-24%,22%) scale(.8)}}
@keyframes h3{to{transform:translate(-34%,-10%) scale(1.25)}}
@keyframes h4{to{transform:translate(-40%,24%) scale(.85)}}
@keyframes h5{to{transform:translate(36%,-18%) scale(1.3)}}
@media (prefers-reduced-motion:reduce){.halo i:nth-child(n){animation:none}html{scroll-behavior:auto}}
.hero .pill,.hero h1,.hero .lead,.hero .cta,.hero .meta,.hero .shot{animation:monter .8s cubic-bezier(.2,.7,.2,1) both}
.hero h1{animation-delay:.08s}.hero .lead{animation-delay:.16s}.hero .cta{animation-delay:.24s}.hero .meta{animation-delay:.3s}.hero .shot{animation-delay:.42s}
@keyframes monter{from{opacity:0;transform:translateY(18px)}}
.pill{display:inline-flex;gap:8px;align-items:center;font-size:13.5px;color:var(--dim);border:1px solid var(--line);border-radius:99px;padding:5px 14px;background:color-mix(in srgb,var(--card) 70%,transparent);text-decoration:none}
.pill b{color:var(--la)}.pill:hover{border-color:var(--line2)}
h1{font-size:60px;line-height:1.05;letter-spacing:-1.4px;margin:22px auto 18px;max-width:900px}
h1 span{background:linear-gradient(90deg,#c4620f,#2f6fc0 50%,#17866a);-webkit-background-clip:text;background-clip:text;color:transparent}
@media (prefers-color-scheme:dark){h1 span{background-image:linear-gradient(90deg,var(--oa),var(--sa) 50%,var(--la))}}
.lead{font-size:20px;color:var(--dim);max-width:640px;text-wrap:balance;margin:0 auto 30px}
.cta{display:flex;gap:12px;justify-content:center;flex-wrap:wrap}
.meta{font-size:13.5px;color:var(--dim);margin:14px 0 0}
.meta+.meta{margin-top:6px}.meta a{color:var(--pri);text-decoration:none;font-weight:600}.meta a:hover{text-decoration:underline}
.shot{margin:52px auto 0;max-width:1080px;border:1px solid var(--line);border-bottom:0;border-radius:14px 14px 0 0;overflow:hidden;background:var(--card);box-shadow:var(--shadow)}
.shot .bar{display:flex;gap:6px;padding:10px 12px;border-bottom:1px solid var(--line);background:var(--bg)}
.shot .bar b{width:10px;height:10px;border-radius:50%;background:var(--line2)}
.layers{display:flex;height:4px}.layers span{flex:1}
.diapo{position:relative;aspect-ratio:1440/860;overflow:hidden;background:var(--card)}
.diapo img{position:absolute;inset:0;width:100%;height:100%;display:block;opacity:0;transition:opacity .9s ease}.diapo img.on{opacity:1}
.diapo .pts{position:absolute;left:0;right:0;bottom:10px;display:flex;justify-content:center;gap:7px;z-index:1}
.diapo .pts button{width:9px;height:9px;border-radius:50%;border:0;padding:0;background:rgba(255,255,255,.7);box-shadow:0 0 0 1px rgba(0,0,0,.3);cursor:pointer}
.diapo .pts button[aria-current=true]{background:var(--pri);transform:scale(1.3)}.diapo .pts button:focus-visible{outline:2px solid var(--pri);outline-offset:2px}
@media (prefers-reduced-motion:reduce){.diapo img{transition:none}}

/* Garanties */
.trust{border-top:1px solid var(--line);border-bottom:1px solid var(--line);background:var(--bg2);position:relative}
.trust .wrap{display:grid;grid-template-columns:repeat(4,1fr);gap:20px;padding:24px}
.trust div{display:flex;gap:12px;align-items:flex-start;font-size:14px;color:var(--dim)}
.trust strong{display:block;color:var(--ink);font-size:15px}
.ico{font-size:22px;line-height:1.1}

/* Sections */
section{padding:84px 0}
.eyebrow{text-transform:uppercase;letter-spacing:.12em;font-size:12.5px;font-weight:700;color:var(--pri)}
h2{font-size:36px;letter-spacing:-.6px;margin:8px 0 12px;line-height:1.15}
.sub{color:var(--dim);font-size:18px;max-width:700px;margin:0 0 38px}
.steps{display:grid;grid-template-columns:repeat(3,1fr);gap:20px}
.step{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:22px}
.step em{font-style:normal;display:inline-grid;place-items:center;width:30px;height:30px;border-radius:50%;background:var(--pri);color:#fff;font-weight:700;margin-bottom:10px}
@media (prefers-color-scheme:dark){.step em{color:#0e1016}}
.step h3{margin:0 0 6px;font-size:18px}.step p{margin:0;color:var(--dim);font-size:15px}
.step,.steps .box,.trust .wrap>div,.lay,.arc{transition:transform .3s cubic-bezier(.2,.7,.2,1),box-shadow .3s,border-color .3s}
.step:hover,.steps .box:hover,.arc:hover{transform:translateY(-4px);box-shadow:0 18px 40px -22px rgba(20,30,70,.4);border-color:var(--line2)}.lay:hover{transform:translateX(6px)}

/* Pile des couches ARCADIA */
.arcadia{display:grid;grid-template-columns:1fr 1.1fr;gap:56px;align-items:center}
.stack{display:flex;flex-direction:column;gap:10px}
.lay{display:grid;grid-template-columns:62px 1fr;gap:4px 14px;align-items:center;padding:14px 18px;border-radius:10px;background:var(--card);border:1px solid var(--line);border-left:8px solid var(--c);margin-left:calc(var(--n)*18px)}
.lay b{grid-row:span 2;font-size:13px;font-weight:700;color:#1b1d29;background:var(--c);border-radius:5px;padding:3px 0;text-align:center}
.lay span{font-weight:600;font-size:15.5px}.lay small{color:var(--dim);font-size:13.5px}

/* Galerie à onglets */
.gal{display:grid;grid-template-columns:330px 1fr;gap:28px;align-items:start}
.tabs{display:flex;flex-direction:column;gap:4px}
.tab{text-align:left;background:transparent;border:1px solid transparent;color:var(--ink);border-radius:12px;padding:12px 16px;cursor:pointer;font:inherit}
.tab strong{display:block;font-size:15.5px;font-weight:600}
.tab span{display:none;color:var(--dim);font-size:14px;margin-top:4px}
.tab{transition:background .2s,transform .25s cubic-bezier(.2,.7,.2,1),box-shadow .25s}.tab:hover{background:color-mix(in srgb,var(--card) 60%,transparent);transform:translateX(4px)}
.tab[aria-selected=true]{background:var(--card);border-color:var(--line);box-shadow:0 6px 18px -12px rgba(30,40,90,.4)}
.tab[aria-selected=true] span{display:block}
.tab[aria-selected=true] strong::before{content:"";display:inline-block;width:8px;height:8px;border-radius:50%;background:var(--c);margin-right:10px;vertical-align:middle}
.view{border:1px solid var(--line);border-radius:14px;overflow:hidden;background:var(--card);box-shadow:var(--shadow);position:sticky;top:84px}
.view img{width:100%;transition:opacity .25s}
.view figcaption{font-size:13px;color:var(--dim);padding:9px 14px;border-top:1px solid var(--line)}

/* Téléchargement */
#telecharger{background:var(--bg2);border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.dlband{display:grid;grid-template-columns:1.1fr 1fr;gap:40px;align-items:center}
.seg{display:inline-flex;border:1px solid var(--line);border-radius:99px;padding:4px;margin:6px 0 20px;background:var(--bg)}
.seg button{border:0;background:transparent;color:var(--dim);font:inherit;font-size:14.5px;padding:7px 16px;border-radius:99px;cursor:pointer}
.seg button[aria-pressed=true]{background:var(--ink);color:var(--bg)}
.file{font-family:ui-monospace,Consolas,monospace;font-size:13px;color:var(--dim);margin-top:14px;word-break:break-all}
.dlside{display:flex;flex-direction:column;gap:14px}
.term{background:var(--code);border:1px solid var(--line);border-radius:12px;padding:18px;font-family:ui-monospace,Consolas,monospace;font-size:13.5px;color:var(--code-ink);overflow:auto;white-space:pre}
.term .c{color:#7d84a0}.term .g{color:var(--la)}
.dlnote{font-size:14.5px;color:var(--dim);display:flex;gap:22px;flex-wrap:wrap}

/* Arcature */
.arc{display:flex;gap:22px;align-items:center;border:1px dashed var(--line2);border-radius:var(--r);padding:24px 28px;background:var(--card)}
.arc p{margin:4px 0 0;color:var(--dim)}
.fmts{display:flex;flex-wrap:wrap;gap:6px;margin-top:10px}.fmts b{font-size:12.5px;font-weight:600;padding:3px 10px;border-radius:99px;background:var(--pri-bg);color:var(--ink)}

/* FAQ */
details{background:var(--card);border:1px solid var(--line);border-radius:10px;padding:14px 18px;margin-bottom:10px}
summary{font-weight:600;cursor:pointer;transition:color .2s}summary:hover{color:var(--pri)}details p{color:var(--dim);margin:10px 0 0}details[open]>p{animation:monter .4s ease both}

/* Page Télécharger */
.page h1{font-size:40px;text-align:left;margin:48px 0 6px;letter-spacing:-.6px}
.main{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:26px 28px;display:grid;grid-template-columns:1fr auto;gap:20px;align-items:center}
.main h2{margin:0;font-size:23px}.main p{margin:4px 0 0;color:var(--dim)}
.tag{font-size:12px;font-weight:700;color:#1d7a52;background:#dff4ea;border-radius:99px;padding:2px 9px;margin-left:8px;vertical-align:middle;letter-spacing:0}
.files{margin-top:18px;background:var(--card);border:1px solid var(--line);border-radius:var(--r);overflow:hidden}
.row{display:grid;grid-template-columns:1.1fr 2.1fr .6fr 200px;gap:16px;align-items:center;padding:14px 22px;border-top:1px solid var(--line);font-size:15px}
.row:first-child{border-top:0}.row>a{justify-self:end}.row code{font-size:12px;color:var(--dim);word-break:break-all}
.grid2{display:grid;grid-template-columns:1fr 1fr;gap:20px;margin-top:22px}
.box{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:22px}
.box h3{margin:0 0 10px;font-size:18px}.box ul{margin:0;padding-left:20px;color:var(--dim)}.box li{margin:4px 0}
.box .term{margin-top:10px}

.gal>*,.grid2>*,.dlband>*,.arcadia>*,.main>*{min-width:0}

/* Apparition au défilement (classe posée par site.js ; sans script, tout est visible) */
.reveal{opacity:0;transform:translateY(22px);transition:opacity .7s ease,transform .7s cubic-bezier(.2,.7,.2,1)}
.lay.reveal{transform:translateX(-28px)}.reveal.in{opacity:1;transform:none}
@media (prefers-reduced-motion:reduce){
  .reveal{opacity:1;transform:none;transition:none}.hero .pill,.hero h1,.hero .lead,.hero .cta,.hero .meta,.hero .shot,details[open]>p{animation:none}
  .btn:hover,.step:hover,.steps .box:hover,.arc:hover,.lay:hover,.tab:hover{transform:none}nav a::after{transition:none}
}

/* Pied */
footer{border-top:1px solid var(--line);padding:34px 0;color:var(--dim);font-size:14px;margin-top:0}
footer .wrap{display:flex;justify-content:space-between;gap:20px;flex-wrap:wrap}
footer a{color:var(--dim);text-decoration:none;margin-right:18px}footer a:hover{color:var(--ink)}

@media (max-width:1100px){nav{gap:14px}nav a{font-size:14px}}
@media (max-width:920px){
  nav{display:none}header .wrap{gap:14px}header .btn{white-space:nowrap}h1{font-size:40px;letter-spacing:-.8px}.lead{font-size:18px}
  .trust .wrap,.steps,.arcadia,.gal,.dlband,.grid2,.main,.row{grid-template-columns:1fr}
  .lay{margin-left:0}.view{position:static}
  .tabs{flex-direction:row;overflow-x:auto;padding-bottom:6px}.tab{flex:0 0 auto}.tab span{display:none!important}
  section{padding:60px 0}.page h1{font-size:32px}
}