/* ============================================================
   Julien Bréal — julien-breal.fr
   Design system : noir / blanc / cyan électrique
   ============================================================ */
:root{
  --black:#0A0B0D;
  --ink:#15181D;
  --white:#FFFFFF;
  --gray:#5B6470;
  --gray-soft:#8A93A0;
  --gray-line:#E8EAEE;
  --panel:#F5F6F8;
  --panel-dark:#0E1116;
  --cyan:#12E0E8;
  --cyan-deep:#0AA6AD;
  --amber:#FF7A3D;
  --radius:16px;
  --radius-sm:10px;
  --shadow-card:0 1px 2px rgba(10,11,13,.04), 0 8px 24px -12px rgba(10,11,13,.10);
  --shadow-lift:0 2px 4px rgba(10,11,13,.05), 0 18px 40px -16px rgba(10,11,13,.18);
}
*{box-sizing:border-box; margin:0; padding:0;}
html{scroll-behavior:smooth;}
body{
  font-family:'Inter', -apple-system, 'Segoe UI', sans-serif;
  color:var(--black);
  background:var(--white);
  line-height:1.55;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
h1,h2,h3,.display{
  font-family:'Space Grotesk', sans-serif;
  letter-spacing:-0.025em;
  text-wrap:balance;
}
.mono{font-family:'IBM Plex Mono', monospace; letter-spacing:0.02em;}
a{color:inherit; text-decoration:none;}
a:hover{color:var(--cyan-deep);}
.wrap{max-width:1180px; margin:0 auto; padding:0 28px;}
img{max-width:100%; display:block;}
::selection{background:var(--cyan); color:var(--black);}
:focus-visible{outline:2px solid var(--cyan); outline-offset:2px;}

/* ------------------------------------------------ Header --- */
header{
  position:sticky; top:0; z-index:50;
  background:rgba(255,255,255,.86);
  backdrop-filter:blur(14px); -webkit-backdrop-filter:blur(14px);
  border-bottom:1px solid var(--gray-line);
  padding:14px 0;
}
.header-inner{display:flex; align-items:center; gap:24px;}
.brand{display:flex; align-items:center; gap:12px;}
.brand:hover{color:inherit;}
.brand-mark{
  width:38px; height:38px; border-radius:11px;
  background:linear-gradient(140deg, #0A0B0D 0%, #0E2A32 55%, #0AA6AD 100%);
  color:#fff; display:flex; align-items:center; justify-content:center;
  font-family:'Space Grotesk'; font-weight:700; font-size:15px; letter-spacing:0.02em;
  flex-shrink:0; position:relative; overflow:hidden;
  box-shadow:inset 0 0 0 1px rgba(255,255,255,.10), 0 4px 12px -4px rgba(10,166,173,.5);
  text-shadow:0 1px 2px rgba(0,0,0,.35);
}
.brand-mark::after{
  content:""; position:absolute; top:-40%; left:-30%; width:60%; height:180%;
  background:linear-gradient(90deg, transparent, rgba(18,224,232,.35), transparent);
  transform:rotate(20deg);
}
.logo{font-family:'Space Grotesk'; font-size:17px; font-weight:700; letter-spacing:-0.01em; line-height:1.15;}
.eyebrow-top{font-size:11.5px; color:var(--gray); font-weight:500;}
.nav{display:flex; align-items:center; gap:26px; margin-left:auto;}
.header-right{display:flex; align-items:center; gap:10px;}
.nav-toggle{
  display:none; align-items:center; justify-content:center;
  width:42px; height:42px; font-size:19px; line-height:1;
  background:var(--white); border:1px solid var(--gray-line); border-radius:10px; cursor:pointer; color:var(--black);
}
.nav a.nav-link{font-size:14px; font-weight:600; color:var(--gray);}
.nav a.nav-link:hover{color:var(--black);}
.header-cta{
  background:var(--black); color:var(--white); font-size:13.5px; font-weight:600;
  padding:11px 20px; border-radius:999px; transition:background .15s, transform .15s;
  white-space:nowrap;
}
.header-cta:hover{background:var(--ink); color:var(--white); transform:translateY(-1px);}

/* -------------------------------------------------- Hero --- */
.hero{
  padding:84px 0 64px; position:relative; overflow:hidden;
  background:
    radial-gradient(900px 420px at 85% -10%, rgba(18,224,232,.10), transparent 65%),
    linear-gradient(180deg, #FBFCFD 0%, var(--white) 70%);
}
.hero-grid{display:grid; grid-template-columns:1.12fr .88fr; gap:64px; align-items:center; position:relative;}
.hero-eyebrow{
  display:inline-flex; gap:9px; align-items:center; font-size:12.5px; color:var(--gray);
  font-weight:600; margin-bottom:22px; text-transform:uppercase; letter-spacing:0.08em;
  border:1px solid var(--gray-line); background:var(--white); padding:8px 14px; border-radius:999px;
}
.hero-eyebrow::before{content:""; width:7px; height:7px; border-radius:50%; background:var(--cyan); box-shadow:0 0 0 4px rgba(18,224,232,.18);}
.hero h1{font-size:clamp(40px, 5vw, 62px); font-weight:700; line-height:1.02; margin-bottom:24px;}
.hero h1 .hl{background:linear-gradient(95deg, var(--black) 10%, var(--cyan-deep) 60%, var(--cyan) 95%); -webkit-background-clip:text; background-clip:text; color:transparent;}
.hero p.lead{font-size:18.5px; color:var(--gray); max-width:540px; margin-bottom:30px; text-wrap:pretty;}
.tags{display:flex; flex-wrap:wrap; gap:8px; margin-bottom:34px;}
.tags span{
  font-size:13px; font-weight:600; color:var(--ink); background:var(--white);
  border:1px solid var(--gray-line); padding:7px 13px; border-radius:999px;
}
.cta-row{display:flex; align-items:center; gap:18px; flex-wrap:wrap;}
.cta-btn{
  display:inline-flex; align-items:center; gap:10px; font-weight:700; font-size:16px; color:var(--white);
  background:linear-gradient(100deg, var(--black) 0%, #12343B 55%, var(--cyan-deep) 100%);
  padding:17px 30px; border-radius:12px;
  box-shadow:0 12px 32px -10px rgba(10,166,173,.55);
  transition:transform .15s ease, box-shadow .15s ease;
}
.cta-btn:hover{transform:translateY(-2px); color:var(--white); box-shadow:0 16px 38px -10px rgba(10,166,173,.65);}
.cta-btn.small{padding:13px 22px; font-size:14.5px;}
.btn-ghost{
  display:inline-flex; align-items:center; gap:8px; font-weight:600; font-size:15px;
  color:var(--black); padding:16px 22px; border-radius:12px; border:1px solid var(--gray-line);
  background:var(--white); transition:border-color .15s;
}
.btn-ghost:hover{border-color:var(--black); color:var(--black);}
.cta-sub{font-size:13px; color:var(--gray); margin-top:14px;}

.hero-photo{position:relative;}
.hero-photo::before{
  content:""; position:absolute; inset:18px -14px -14px 18px; border-radius:22px;
  background:linear-gradient(135deg, rgba(18,224,232,.28), rgba(18,224,232,0) 55%);
  z-index:0;
}
.hero-photo img{border-radius:20px; width:100%; object-fit:cover; position:relative; z-index:1; box-shadow:var(--shadow-lift);}
.hero-photo .badge{
  position:absolute; bottom:-20px; left:-20px; z-index:2;
  background:var(--black); color:var(--white);
  padding:16px 20px; border-radius:14px; font-size:12.5px; max-width:225px; line-height:1.4;
  box-shadow:var(--shadow-lift);
}
.hero-photo .badge b{display:block; font-size:24px; font-family:'Space Grotesk'; color:var(--cyan); margin-bottom:2px;}

/* ------------------------------------------------- Proof --- */
.proof{padding:52px 0 8px; text-align:center;}
.proof p{font-size:12.5px; color:var(--gray-soft); text-transform:uppercase; letter-spacing:0.1em; margin-bottom:24px; font-weight:600;}
.proof img{margin:0 auto; opacity:.8; max-width:820px; filter:grayscale(1); transition:filter .25s, opacity .25s;}
.proof img:hover{filter:grayscale(0); opacity:1;}

/* ---------------------------------------------- Sections --- */
section{padding:96px 0;}
.section-alt{background:var(--panel);}
.kicker{
  display:inline-flex; align-items:center; gap:8px;
  font-size:12.5px; font-weight:700; color:var(--cyan-deep); text-transform:uppercase; letter-spacing:0.09em; margin-bottom:16px;
  font-family:'IBM Plex Mono', monospace;
}
.kicker::before{content:""; width:22px; height:2px; background:var(--cyan);}
h2{font-size:clamp(28px, 3.4vw, 40px); font-weight:700; margin-bottom:18px; max-width:680px; line-height:1.12;}
.sub{color:var(--gray); font-size:17px; max-width:620px; margin-bottom:48px; text-wrap:pretty;}

/* ----------------------------------------------- Problem --- */
.problem-grid{display:grid; grid-template-columns:1fr 1fr; gap:64px; align-items:center;}
.problem-list{list-style:none;}
.problem-list li{
  display:flex; gap:14px; font-size:16px; color:var(--ink); padding:16px 0;
  border-bottom:1px solid var(--gray-line);
}
.problem-list li:first-child{padding-top:0;}
.problem-list li::before{content:"→"; color:var(--amber); font-weight:700; flex-shrink:0;}
.callout{
  background:var(--panel-dark); color:#E8ECEF; border-radius:var(--radius); padding:34px;
  font-size:18px; line-height:1.55; position:relative; overflow:hidden;
  box-shadow:var(--shadow-lift);
}
.callout::after{
  content:""; position:absolute; top:0; right:0; width:180px; height:180px;
  background:radial-gradient(circle at top right, rgba(18,224,232,.22), transparent 70%);
}
.callout b{color:var(--cyan);}

/* ----------------------------------------------- Process --- */
.process{display:grid; grid-template-columns:repeat(5,1fr); gap:14px;}
.step{
  background:var(--white); border:1px solid var(--gray-line); border-radius:var(--radius); padding:26px 22px;
  box-shadow:var(--shadow-card); transition:transform .18s ease, box-shadow .18s ease;
}
.step:hover{transform:translateY(-4px); box-shadow:var(--shadow-lift);}
.step .num{
  font-family:'IBM Plex Mono'; font-size:12.5px; color:var(--cyan-deep); font-weight:600;
  margin-bottom:18px; display:flex; align-items:center; gap:10px;
}
.step .num::after{content:""; flex:1; height:1px; background:var(--gray-line);}
.step h3{font-size:19px; margin-bottom:10px;}
.step p{color:var(--gray); font-size:14px;}
.step ul{margin-top:14px; padding-left:16px; color:var(--gray); font-size:13.5px;}
.step ul li{margin-bottom:6px;}

/* -------------------------------------------------- Stack --- */
.stack-grid{display:grid; grid-template-columns:repeat(2,1fr); gap:18px;}
.stack-card{
  background:var(--white); border-radius:var(--radius); padding:28px; border:1px solid var(--gray-line);
  display:flex; gap:18px; align-items:flex-start; box-shadow:var(--shadow-card);
  transition:transform .18s ease, box-shadow .18s ease, border-color .18s;
}
.stack-card:hover{transform:translateY(-3px); box-shadow:var(--shadow-lift); border-color:rgba(18,224,232,.5);}
.stack-card .dot{
  width:42px; height:42px; border-radius:12px; background:var(--black); color:var(--cyan);
  display:flex; align-items:center; justify-content:center; font-family:'IBM Plex Mono'; font-size:14px; flex-shrink:0;
}
.stack-card h3{font-size:17.5px; margin-bottom:7px;}
.stack-card p{color:var(--gray); font-size:14.5px;}
.stack-card a.link{color:var(--cyan-deep); font-weight:600; font-size:13.5px; display:inline-block; margin-top:10px;}
.stack-card a.link:hover{color:var(--black);}

/* --------------------------------------------- Resources --- */
.res-grid{display:grid; grid-template-columns:repeat(3,1fr); gap:16px;}
.res-card{
  background:var(--white); border:1px solid var(--gray-line); border-radius:14px; padding:24px;
  display:flex; flex-direction:column; gap:6px; box-shadow:var(--shadow-card);
  transition:transform .18s ease, box-shadow .18s ease, border-color .18s;
}
.res-card:hover{transform:translateY(-3px); border-color:rgba(18,224,232,.55); box-shadow:var(--shadow-lift); color:inherit;}
.res-card .tag{font-size:11px; text-transform:uppercase; letter-spacing:0.06em; color:var(--amber); font-weight:700; margin-bottom:6px; font-family:'IBM Plex Mono';}
.res-card .tag.cyan{color:var(--cyan-deep);}
.res-card h3{font-size:16.5px; font-weight:700; letter-spacing:-0.01em;}
.res-card p{font-size:13.5px; color:var(--gray); flex:1;}
.res-card .go{font-size:13px; font-weight:600; color:var(--cyan-deep); margin-top:10px;}
.group-label{
  display:flex; align-items:center; gap:14px;
  font-size:13px; font-weight:700; color:var(--black); text-transform:uppercase; letter-spacing:0.05em; margin:48px 0 20px;
  font-family:'IBM Plex Mono';
}
.group-label::after{content:""; flex:1; height:1px; background:var(--gray-line);}

/* --------------------------------------------- Final CTA --- */
.final{
  background:var(--panel-dark); color:var(--white); text-align:center; padding:110px 0;
  position:relative; overflow:hidden;
}
.final::before{
  content:""; position:absolute; inset:0;
  background:radial-gradient(700px 320px at 50% 115%, rgba(18,224,232,.16), transparent 70%);
}
.final .wrap{position:relative;}
.final h2{color:var(--white); margin:0 auto 16px; max-width:720px;}
.final p{color:#9CA3AF; max-width:520px; margin:0 auto 36px;}

/* ------------------------------------------------ Footer --- */
footer{background:var(--white); border-top:1px solid var(--gray-line); padding:56px 0 40px;}
.footer-grid{display:grid; grid-template-columns:1.4fr 1fr 1fr; gap:48px; margin-bottom:44px;}
.footer-grid h4{font-size:13px; text-transform:uppercase; letter-spacing:0.06em; color:var(--gray-soft); margin-bottom:16px; font-family:'IBM Plex Mono'; font-weight:600;}
.footer-grid ul{list-style:none; display:flex; flex-direction:column; gap:10px;}
.footer-grid ul a{font-size:14px; color:var(--gray); font-weight:500;}
.footer-grid ul a:hover{color:var(--black);}
.footer-brand p{font-size:14px; color:var(--gray); max-width:300px; margin-top:12px;}
.footer-bottom{border-top:1px solid var(--gray-line); padding-top:24px; display:flex; justify-content:space-between; gap:12px; flex-wrap:wrap; color:var(--gray-soft); font-size:13px;}

/* =================================================== Article */
.article-hero{
  background:
    radial-gradient(700px 300px at 90% -20%, rgba(18,224,232,.10), transparent 65%),
    linear-gradient(180deg, #FBFCFD, var(--white));
  border-bottom:1px solid var(--gray-line);
  padding:64px 0 44px;
}
.article-wrap{max-width:760px; margin:0 auto; padding:0 28px;}
.breadcrumb{font-size:13px; color:var(--gray-soft); font-weight:500; margin-bottom:28px; display:flex; gap:8px; flex-wrap:wrap;}
.breadcrumb a{color:var(--gray); font-weight:600;}
.breadcrumb a:hover{color:var(--black);}
.article-tag{
  display:inline-block; font-size:11.5px; font-weight:700; color:var(--cyan-deep); background:rgba(18,224,232,.10);
  border:1px solid rgba(18,224,232,.35);
  padding:6px 13px; border-radius:999px; letter-spacing:0.06em; text-transform:uppercase; margin-bottom:20px;
  font-family:'IBM Plex Mono';
}
.article-hero h1{font-size:clamp(30px, 4vw, 44px); line-height:1.08; margin-bottom:18px;}
.article-dek{color:var(--gray); font-size:18.5px; max-width:660px; text-wrap:pretty;}
.article-meta{
  display:flex; gap:20px; flex-wrap:wrap; margin-top:26px;
  font-size:13px; color:var(--gray); font-weight:500;
}
.article-meta span{display:inline-flex; align-items:center; gap:7px;}
.article-meta span::before{content:""; width:5px; height:5px; border-radius:50%; background:var(--cyan);}

.toc{
  background:var(--panel); border:1px solid var(--gray-line); border-radius:var(--radius);
  padding:24px 28px; margin:40px 0 8px;
}
.toc .toc-title{font-family:'IBM Plex Mono'; font-size:12px; font-weight:600; text-transform:uppercase; letter-spacing:0.08em; color:var(--gray-soft); margin-bottom:14px;}
.toc ol{list-style:none; counter-reset:toc; display:flex; flex-direction:column; gap:9px;}
.toc ol li{counter-increment:toc; display:flex; gap:12px; align-items:baseline;}
.toc ol li::before{content:counter(toc, decimal-leading-zero); font-family:'IBM Plex Mono'; font-size:12px; color:var(--cyan-deep); font-weight:600;}
.toc ol a{font-size:14.5px; font-weight:600; color:var(--ink);}
.toc ol a:hover{color:var(--cyan-deep);}

.article-body{padding:24px 0 20px; font-size:17px; line-height:1.8; color:#22262C;}
.article-body h2{
  font-size:26px; margin:52px 0 16px; scroll-margin-top:90px;
  padding-top:28px; border-top:1px solid var(--gray-line);
}
.article-body h3{font-family:'Inter'; font-weight:700; font-size:19px; margin:30px 0 10px; letter-spacing:-0.01em;}
.article-body p{margin-bottom:17px; text-wrap:pretty;}
.article-body ul,.article-body ol{margin:0 0 20px 22px;}
.article-body li{margin-bottom:10px;}
.article-body strong{color:var(--black);}
.article-body a{color:var(--cyan-deep); font-weight:600; text-decoration:underline; text-decoration-color:rgba(18,224,232,.5); text-underline-offset:3px;}
.article-body a:hover{text-decoration-color:var(--cyan-deep);}
.article-body em{color:var(--ink);}

.callout-box{
  background:var(--panel); border:1px solid var(--gray-line); border-left:3px solid var(--cyan);
  padding:22px 26px; border-radius:0 12px 12px 0;
  margin:30px 0; font-size:16px;
}
.callout-box p:last-child{margin-bottom:0;}
.callout-box.warn{border-left-color:var(--amber);}

.prompt-box{
  background:var(--panel-dark); color:#D9FDFE; font-family:'IBM Plex Mono'; font-size:14px;
  padding:18px 22px 18px 20px; border-radius:12px; margin:0 0 12px; line-height:1.65;
  position:relative; border:1px solid rgba(18,224,232,.14);
}
.prompt-box::before{
  content:"PROMPT"; display:block; font-size:10px; letter-spacing:0.14em; color:var(--cyan);
  opacity:.75; margin-bottom:8px;
}

.faq-item{border-bottom:1px solid var(--gray-line); padding:20px 0;}
.faq-item h3{margin:0 0 8px !important;}
.faq-item p{margin-bottom:0; color:var(--gray); font-size:16px;}

.related{margin:56px 0 8px;}
.related .group-label{margin-top:0;}
.related .res-grid{grid-template-columns:repeat(3,1fr);}

.article-cta{
  background:var(--panel-dark); color:var(--white); border-radius:var(--radius); padding:44px 36px; text-align:center; margin:48px 0 24px;
  position:relative; overflow:hidden;
}
.article-cta::before{
  content:""; position:absolute; inset:0;
  background:radial-gradient(420px 200px at 50% 120%, rgba(18,224,232,.18), transparent 70%);
}
.article-cta h3, .article-cta p, .article-cta a{position:relative;}
.article-cta h3{font-size:22px; margin-bottom:10px; color:var(--white);}
.article-cta p{color:#9CA3AF; margin-bottom:22px; font-size:15.5px;}

/* --------------------------------------------- Responsive --- */
@media (max-width:1020px){
  .process{grid-template-columns:repeat(2,1fr);}
  .nav-toggle{display:inline-flex;}
  .nav{
    position:absolute; top:100%; left:0; right:0; margin-left:0;
    background:var(--white); border-bottom:1px solid var(--gray-line);
    flex-direction:column; align-items:stretch; padding:6px 28px 18px;
    display:none; box-shadow:0 22px 34px -22px rgba(10,11,13,.28);
  }
  header.nav-open .nav{display:flex;}
  .nav a.nav-link{display:block; padding:13px 0; border-bottom:1px solid var(--gray-line); font-size:16px; color:var(--black);}
  .nav a.nav-link:last-child{border-bottom:none;}
}
@media (max-width:860px){
  section{padding:64px 0;}
  .hero{padding:56px 0 48px;}
  .hero-grid, .problem-grid{grid-template-columns:1fr; gap:44px;}
  .process, .res-grid, .stack-grid, .related .res-grid{grid-template-columns:1fr;}
  .footer-grid{grid-template-columns:1fr; gap:32px;}
  .hero-photo{max-width:420px;}
  .hero-photo .badge{position:static; margin-top:16px; max-width:none;}
  .article-hero{padding:44px 0 36px;}
}