/* =========================================================================
   intelligenceartificielle.com — feuille de style
   Polices auto-hébergées (RGPD) · Spectral + IBM Plex Mono
   ========================================================================= */

@font-face{font-family:'Spectral';font-style:normal;font-weight:300;font-display:swap;
  src:url('/assets/fonts/spectral-300.woff2') format('woff2')}
@font-face{font-family:'Spectral';font-style:normal;font-weight:400;font-display:swap;
  src:url('/assets/fonts/spectral-400.woff2') format('woff2')}
@font-face{font-family:'Spectral';font-style:normal;font-weight:500;font-display:swap;
  src:url('/assets/fonts/spectral-500.woff2') format('woff2')}
@font-face{font-family:'Spectral';font-style:normal;font-weight:600;font-display:swap;
  src:url('/assets/fonts/spectral-600.woff2') format('woff2')}
@font-face{font-family:'Spectral';font-style:italic;font-weight:400;font-display:swap;
  src:url('/assets/fonts/spectral-400-italic.woff2') format('woff2')}
@font-face{font-family:'IBM Plex Mono';font-style:normal;font-weight:400;font-display:swap;
  src:url('/assets/fonts/plexmono-400.woff2') format('woff2')}
@font-face{font-family:'IBM Plex Mono';font-style:normal;font-weight:500;font-display:swap;
  src:url('/assets/fonts/plexmono-500.woff2') format('woff2')}

:root{
  --ink:#16202B;
  --ink-soft:#3B4654;
  --muted:#6B7682;
  --paper:#F2F3F4;
  --surface:#FFFFFF;
  --rule:#DCDFE3;
  --rule-strong:#C0C5CC;
  --accent:#283C6E;          /* indigo profond */
  --accent-bright:#3350A8;
  --serif:'Spectral',Georgia,'Times New Roman',serif;
  --mono:'IBM Plex Mono',ui-monospace,SFMono-Regular,Menlo,monospace;
  --measure:68ch;
  --gutter:clamp(1.25rem,5vw,4rem);
}

*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{
  margin:0;
  background:var(--paper);
  color:var(--ink);
  font-family:var(--serif);
  font-weight:400;
  font-size:clamp(1.02rem,0.96rem + 0.3vw,1.18rem);
  line-height:1.62;
  font-feature-settings:"liga" 1,"onum" 1,"kern" 1;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
a{color:inherit}
img{max-width:100%;display:block}
hr{border:0;border-top:1px solid var(--rule);margin:0}

/* ---- texture papier très discrète ---- */
body::before{
  content:"";position:fixed;inset:0;pointer-events:none;z-index:0;
  background:
    radial-gradient(120% 80% at 50% -10%, rgba(40,60,110,0.04), transparent 60%);
}

/* ---- structure ---- */
.wrap{width:min(100% - 2*var(--gutter),74rem);margin-inline:auto;position:relative;z-index:1}
.measure{max-width:var(--measure)}

/* ---- libellés mono ---- */
.eyebrow,.mono{
  font-family:var(--mono);font-weight:500;
  text-transform:uppercase;letter-spacing:0.14em;
  font-size:0.7rem;color:var(--muted);
}

/* ---- nav secondaire du bandeau ---- */
.mast-nav{display:flex;align-items:center;gap:1rem}
.nav-letter{
  font-family:var(--mono);font-weight:500;font-size:0.66rem;letter-spacing:0.14em;
  text-transform:uppercase;text-decoration:none;color:var(--ink-soft);cursor:pointer;
  border-bottom:1px solid transparent;padding-bottom:2px;
  transition:color .15s ease,border-color .15s ease;
}
.nav-letter:hover,.nav-letter:focus-visible{color:var(--accent);border-color:var(--accent)}

/* ---- sceau d'identité (signature) ---- */
.seal{
  display:inline-flex;align-items:center;gap:0.5ch;
  font-family:var(--mono);font-weight:500;font-size:0.66rem;letter-spacing:0.18em;
  text-transform:uppercase;color:var(--accent);
  border:1px solid var(--accent);border-radius:2px;
  padding:0.3rem 0.6rem;text-decoration:none;line-height:1;
}
.seal::before{content:"§";font-weight:600;opacity:.7}

/* ====================== MASTHEAD ====================== */
.masthead{padding-block:clamp(1.4rem,3vw,2.2rem)}
.masthead .wrap{
  display:flex;align-items:center;justify-content:space-between;gap:1.5rem;
  border-bottom:1px solid var(--rule);padding-bottom:1.2rem;
}
.brand{display:flex;flex-direction:column;gap:0.35rem;text-decoration:none}
.brand .name{
  font-family:var(--serif);font-weight:500;font-size:clamp(1.15rem,1rem + 0.7vw,1.5rem);
  letter-spacing:-0.01em;line-height:1;color:var(--ink);
}
.brand .name b{font-weight:600}
.brand .kicker{
  font-family:var(--mono);font-size:0.62rem;letter-spacing:0.2em;text-transform:uppercase;
  color:var(--muted);
}

/* ====================== HÉRO / NOTE EN UNE ====================== */
.hero{padding-block:clamp(2.6rem,7vw,5.5rem)}
.dossier{
  display:flex;flex-wrap:wrap;gap:0.6rem 1.6rem;align-items:baseline;
  padding-bottom:1.4rem;
}
.dossier .lead{color:var(--accent)}
.hero h1{
  font-family:var(--serif);font-weight:600;
  font-size:clamp(2.1rem,1.3rem + 3.4vw,4.1rem);
  line-height:1.04;letter-spacing:-0.015em;
  margin:0;max-width:18ch;color:var(--ink);
  text-wrap:balance;
}
.hero .standfirst{
  font-weight:300;font-size:clamp(1.18rem,1.05rem + 0.6vw,1.55rem);
  line-height:1.5;color:var(--ink-soft);
  margin:1.5rem 0 0;max-width:56ch;
}
.hero .standfirst em{font-style:italic;color:var(--ink)}

.hero-foot{
  display:flex;flex-wrap:wrap;align-items:center;gap:1rem 1.6rem;
  margin-top:2.4rem;
}
.cta{
  display:inline-flex;align-items:center;gap:0.7ch;text-decoration:none;
  font-family:var(--mono);font-weight:500;font-size:0.78rem;letter-spacing:0.06em;
  color:var(--surface);background:var(--accent);
  padding:0.85rem 1.4rem;border-radius:2px;
  transition:background .18s ease,transform .18s ease;
}
.cta .arrow{transition:transform .18s ease}
.cta:hover{background:var(--accent-bright)}
.cta:hover .arrow{transform:translateX(3px)}
.byline{font-family:var(--mono);font-size:0.72rem;letter-spacing:0.04em;color:var(--muted)}
.byline b{color:var(--ink-soft);font-weight:500}

/* ====================== DÉCLARATION ====================== */
.statement{border-top:1px solid var(--rule);padding-block:clamp(2.2rem,5vw,3.6rem)}
.statement .grid{display:grid;grid-template-columns:minmax(0,14rem) 1fr;gap:1.4rem 3rem}
.statement h2{
  font-family:var(--mono);font-weight:500;font-size:0.72rem;letter-spacing:0.16em;
  text-transform:uppercase;color:var(--muted);margin:0.4rem 0 0;
}
.statement p{margin:0 0 1rem;font-size:clamp(1.05rem,1rem + 0.3vw,1.22rem);color:var(--ink-soft)}
.statement p:last-child{margin-bottom:0}
.statement strong{font-weight:500;color:var(--ink)}

/* ====================== ARTICLE (page note) ====================== */
.note-head{padding-block:clamp(2.4rem,6vw,4.4rem) clamp(1.6rem,4vw,2.6rem)}
.backlink{
  font-family:var(--mono);font-size:0.7rem;letter-spacing:0.08em;text-transform:uppercase;
  color:var(--muted);text-decoration:none;display:inline-flex;gap:0.6ch;align-items:center;
}
.backlink:hover{color:var(--accent)}
.note-head h1{
  font-family:var(--serif);font-weight:600;
  font-size:clamp(1.9rem,1.2rem + 2.8vw,3.4rem);
  line-height:1.08;letter-spacing:-0.012em;margin:1.4rem 0 0;max-width:22ch;
  text-wrap:balance;
}
.note-head .standfirst{
  font-weight:300;font-size:clamp(1.12rem,1.02rem + 0.5vw,1.42rem);line-height:1.5;
  color:var(--ink-soft);margin:1.4rem 0 0;max-width:54ch;
}
.byline-note{
  font-style:italic;color:var(--ink-soft);font-size:1.02rem;
  margin:1.2rem 0 0;
}
.byline-note strong{font-style:normal;font-weight:500;color:var(--ink)}
.note-meta{
  display:flex;flex-wrap:wrap;gap:0.5rem 1.6rem;align-items:baseline;
  margin-top:1.5rem;padding-top:1.2rem;border-top:1px solid var(--rule);
}
.note-actions{margin:1.2rem 0 0}
.pdf-link{
  display:inline-flex;align-items:center;gap:0.6ch;
  font-family:var(--mono);font-weight:500;font-size:0.72rem;letter-spacing:0.06em;
  text-transform:uppercase;text-decoration:none;color:var(--accent);
  border:1px solid var(--accent);border-radius:2px;padding:0.55rem 0.95rem;
  transition:background .18s ease,color .18s ease;
}
.pdf-link:hover{background:var(--accent);color:var(--surface)}

.article{padding-bottom:clamp(3rem,8vw,6rem)}
.article .body{max-width:var(--measure);font-size:clamp(1.08rem,1.02rem + 0.35vw,1.24rem)}
.article .body > *:first-child{margin-top:0}
.article p{margin:0 0 1.4em}
.article strong{font-weight:600;color:var(--ink)}
.article h2{
  font-family:var(--serif);font-weight:600;font-size:clamp(1.4rem,1.2rem + 0.8vw,1.9rem);
  line-height:1.2;margin:2.4em 0 0.7em;letter-spacing:-0.01em;
}
.article h3{font-weight:600;font-size:1.25rem;margin:2em 0 0.5em}
.article blockquote{
  margin:2em 0;padding:0.2em 0 0.2em 1.4rem;border-left:2px solid var(--accent);
  font-style:italic;font-weight:400;color:var(--ink);font-size:1.12em;
}
.article a{color:var(--accent);text-decoration:underline;text-underline-offset:3px;
  text-decoration-thickness:1px;text-decoration-color:var(--rule-strong)}
.article a:hover{text-decoration-color:var(--accent)}
.article ul,.article ol{padding-left:1.3em;margin:0 0 1.4em}
.article li{margin:0.4em 0}
.colophon{
  max-width:var(--measure);margin-top:3rem;padding-top:1.4rem;border-top:1px solid var(--rule);
  font-size:0.92rem;color:var(--muted);font-style:italic;
}
.colophon a{color:var(--accent)}

/* tableaux (chronologie) */
.article .body table{
  width:100%;border-collapse:collapse;margin:1.6em 0;font-size:0.92rem;line-height:1.45;
}
.article .body thead th{
  text-align:left;font-family:var(--mono);font-weight:500;font-size:0.66rem;
  letter-spacing:0.12em;text-transform:uppercase;color:var(--muted);
  padding:0 1rem 0.6rem 0;border-bottom:1px solid var(--rule-strong);
}
.article .body tbody td{
  padding:0.7rem 1rem 0.7rem 0;border-bottom:1px solid var(--rule);vertical-align:baseline;
}
.article .body tbody tr td:first-child{
  font-family:var(--mono);font-size:0.78rem;color:var(--accent);white-space:nowrap;
  padding-right:1.6rem;font-weight:500;
}
@media (max-width:640px){
  .article .body tbody tr td:first-child{white-space:normal}
}

/* bloc « version / mise à jour » en tête de note */
.version-note{
  margin:0 0 0;padding:1rem 1.2rem;background:var(--surface);
  border:1px solid var(--rule);border-left:2px solid var(--accent);border-radius:2px;
  font-size:0.86rem;line-height:1.55;color:var(--ink-soft);max-width:var(--measure);
}
.version-note .vtag{
  font-family:var(--mono);font-weight:500;font-size:0.64rem;letter-spacing:0.14em;
  text-transform:uppercase;color:var(--accent);display:block;margin-bottom:0.4rem;
}
.version-note em{font-style:italic;color:var(--muted)}

/* glossaire : libellés de tête en évidence */
.article .body hr{margin:2.4em 0}

/* ====================== PIED ====================== */
.site-foot{border-top:1px solid var(--rule);margin-top:auto;padding-block:2.4rem 3rem}
.site-foot .wrap{display:flex;flex-wrap:wrap;justify-content:space-between;gap:1rem}
.site-foot .mono{font-size:0.68rem;color:var(--muted)}
.site-foot a{text-decoration:none;color:var(--muted)}
.site-foot a:hover{color:var(--accent)}

/* ====================== ACCESSIBILITÉ ====================== */
:focus-visible{outline:2px solid var(--accent-bright);outline-offset:3px;border-radius:2px}
.skip{position:absolute;left:-999px}
.skip:focus{left:1rem;top:1rem;z-index:10;background:var(--surface);padding:0.6rem 1rem;
  border:1px solid var(--accent);border-radius:2px;font-family:var(--mono);font-size:0.8rem}

/* ====================== LETTRE / NEWSLETTER ====================== */
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;
  clip:rect(0,0,0,0);white-space:nowrap;border:0}

.nl{
  position:fixed;left:50%;bottom:1.2rem;
  transform:translateX(-50%) translateY(150%);
  width:min(100% - 2rem,30rem);
  background:var(--surface);
  border:1px solid var(--rule-strong);border-top:2px solid var(--accent);border-radius:4px;
  box-shadow:0 12px 44px rgba(20,32,43,.18);
  padding:1.25rem 1.35rem 1.3rem;z-index:60;
  transition:transform .5s cubic-bezier(.2,.7,.2,1),opacity .5s ease;
  opacity:0;
}
.nl.show{transform:translateX(-50%) translateY(0);opacity:1}
.nl-eyebrow{font-family:var(--mono);font-weight:500;font-size:0.64rem;letter-spacing:0.18em;
  text-transform:uppercase;color:var(--accent);margin:0 0 0.5rem}
.nl-title{font-family:var(--serif);font-weight:600;font-size:1.18rem;line-height:1.2;
  letter-spacing:-0.01em;margin:0;color:var(--ink)}
.nl-sub{font-size:0.9rem;line-height:1.45;color:var(--ink-soft);margin:0.5rem 0 0}
.nl form{display:flex;flex-wrap:wrap;gap:0.5rem;margin:0.95rem 0 0}
.nl input[type=email]{
  flex:1 1 12rem;min-width:0;font-family:var(--serif);font-size:0.98rem;color:var(--ink);
  padding:0.72rem 0.85rem;background:var(--paper);
  border:1px solid var(--rule-strong);border-radius:2px;}
.nl input[aria-invalid=true]{border-color:#a23;}
.nl button[type=submit]{
  flex:0 0 auto;font-family:var(--mono);font-weight:500;font-size:0.78rem;letter-spacing:0.04em;
  color:var(--surface);background:var(--accent);border:0;border-radius:2px;
  padding:0.72rem 1.1rem;cursor:pointer;transition:background .18s ease;}
.nl button[type=submit]:hover{background:var(--accent-bright)}
.nl button[type=submit]:disabled{opacity:.6;cursor:default}
.nl-error{flex:1 1 100%;margin:0.1rem 0 0;font-size:0.78rem;color:#a23}
.nl-legal{flex:1 1 100%;font-size:0.72rem;line-height:1.45;color:var(--muted);margin:0.7rem 0 0}
.nl-legal a{color:var(--accent)}
.nl-done{font-size:0.98rem;color:var(--ink);margin:0.4rem 0 0;font-style:italic}
.nl-close{position:absolute;top:0.45rem;right:0.6rem;width:1.8rem;height:1.8rem;
  background:none;border:0;color:var(--muted);font-size:1.25rem;line-height:1;cursor:pointer;border-radius:2px}
.nl-close:hover{color:var(--accent)}
@media (max-width:560px){
  .nl{left:0;right:0;bottom:0;width:100%;border-radius:4px 4px 0 0;transform:translateY(120%)}
  .nl.show{transform:translateY(0)}
}

/* ====================== MOUVEMENT (discret) ====================== */
@keyframes rise{from{opacity:0;transform:translateY(10px)}to{opacity:1;transform:none}}
.reveal{animation:rise .7s cubic-bezier(.2,.7,.2,1) both}
.reveal.d1{animation-delay:.06s}
.reveal.d2{animation-delay:.14s}
.reveal.d3{animation-delay:.22s}
.reveal.d4{animation-delay:.30s}

@media (prefers-reduced-motion:reduce){
  .reveal{animation:none}
  *{transition:none!important;scroll-behavior:auto!important}
}

/* ====================== RESPONSIVE ====================== */
@media (max-width:640px){
  .statement .grid{grid-template-columns:1fr;gap:0.6rem}
  .masthead .wrap{flex-direction:column;align-items:flex-start;gap:1rem}
  .article .body > p:first-of-type::first-letter{font-size:3em}
}

/* layout colonne pleine hauteur pour coller le pied en bas */
html,body{min-height:100%}
body{display:flex;flex-direction:column}
main{flex:1 0 auto}