/* L4 Networks — feuille de style unique
   Identité visuelle reprise du logo officiel (brand/L4_NETWORKS_Logo_Dark.ai) :
   fond anthracite, L orange, N bleu, carré vert, mot argent.
   Les noms de variables historiques sont conservés : --rack = fond sombre,
   --os2 = orange (action), --om3 = bleu (liens), --green = carré du logo. */

@font-face { font-family: "Barlow"; src: url("/fonts/barlow-latin-400-normal.woff2") format("woff2"); font-weight: 400; font-display: swap; }
@font-face { font-family: "Barlow"; src: url("/fonts/barlow-latin-500-normal.woff2") format("woff2"); font-weight: 500; font-display: swap; }
@font-face { font-family: "Barlow"; src: url("/fonts/barlow-latin-600-normal.woff2") format("woff2"); font-weight: 600; font-display: swap; }
@font-face { font-family: "Barlow Semi Condensed"; src: url("/fonts/barlow-semi-condensed-latin-500-normal.woff2") format("woff2"); font-weight: 500; font-display: swap; }
@font-face { font-family: "Barlow Semi Condensed"; src: url("/fonts/barlow-semi-condensed-latin-600-normal.woff2") format("woff2"); font-weight: 600; font-display: swap; }
@font-face { font-family: "Barlow Semi Condensed"; src: url("/fonts/barlow-semi-condensed-latin-700-normal.woff2") format("woff2"); font-weight: 700; font-display: swap; }

:root {
  --rack: #1a1a1a;        /* anthracite du logo : en-tête, hero, contact */
  --rack-2: #242424;
  --rack-line: #3a3a3a;   /* filets sur fond sombre */
  --on-dark: #d6d6d6;     /* texte courant sur fond sombre */
  --on-dark-muted: #a3a3a3;
  --ink: #1f1f1f;         /* texte */
  --muted: #5c5c5c;
  --paper: #f5f5f3;       /* fond clair */
  --white: #ffffff;
  --line: #dcdcd8;
  --os2: #f7931e;         /* orange du L : boutons, couche L4, focus sur fond sombre */
  --os2-deep: #f15a24;    /* bas du dégradé orange */
  --os2-text: #b8470f;    /* orange lisible sur fond clair (contraste 4,9:1) */
  --om3: #0071bc;         /* bleu du N : liens sur fond clair */
  --om3-light: #29abe2;   /* bleu clair : liens et couches actives sur fond sombre */
  --green: #8cc63f;       /* carré du logo : touches ponctuelles */
  --green-light: #d9e021;
  --green-text: #4d7c0f;
  --silver: #e6e6e6;
  --brand-strip: linear-gradient(90deg, var(--os2) 0 50%, var(--om3-light) 50% 80%, var(--green) 80%);
  --danger: #b3261e;

  --f-body: "Barlow", system-ui, sans-serif;
  --f-head: "Barlow Semi Condensed", "Barlow", system-ui, sans-serif;
  --wrap: 72rem;
  --gutter: clamp(1rem, 4vw, 2.5rem);
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 400 1.0625rem/1.6 var(--f-body);
}

h1, h2, h3 { font-family: var(--f-head); line-height: 1.12; margin: 0; color: var(--rack); }
h1 { font-weight: 700; font-size: clamp(2.4rem, 5.6vw, 4rem); letter-spacing: -0.01em; }
h2 { font-weight: 700; font-size: clamp(1.75rem, 3.4vw, 2.4rem); }
h3 { font-weight: 600; font-size: 1.3rem; }
p { margin: 0 0 1em; }
a { color: var(--om3); text-underline-offset: 0.18em; }
a:hover { color: var(--rack); }
:focus-visible { outline: 3px solid var(--om3); outline-offset: 2px; }
.site-head :focus-visible, .hero :focus-visible, .contact :focus-visible, .site-foot :focus-visible { outline-color: var(--os2); }

/* Libellé de section : petit carré vert, comme le point du logo */
.kicker { display: inline-flex; align-items: center; gap: .55rem; font: 600 .9rem/1 var(--f-head); letter-spacing: .14em; text-transform: uppercase; color: var(--muted); margin-bottom: .9rem; }
.kicker::before { content: ""; width: .6rem; height: .6rem; background: linear-gradient(135deg, var(--green-light), var(--green)); }

.wrap { max-width: var(--wrap); margin: 0 auto; padding: 0 var(--gutter); }
.skip { position: absolute; left: -999px; top: 0; background: var(--os2); color: var(--rack); padding: .5rem 1rem; z-index: 10; }
.skip:focus { left: 0; }

/* ---------- En-tête ---------- */
.site-head { background: var(--rack); color: var(--white); position: relative; }
.site-head::after { content: ""; position: absolute; left: 0; right: 0; bottom: 0; height: 3px; background: var(--brand-strip); }
.site-head .wrap { display: flex; align-items: center; justify-content: space-between; gap: 1rem; min-height: 4.25rem; flex-wrap: wrap; }
.brand { display: inline-flex; align-items: center; padding: .25rem 0; }
.brand img { display: block; height: 2.125rem; width: auto; max-width: 100%; }
.nav { display: flex; gap: clamp(.75rem, 2.5vw, 1.75rem); flex-wrap: wrap; padding: .5rem 0; }
.nav a { color: var(--on-dark); text-decoration: none; font: 600 .95rem/1 var(--f-head); letter-spacing: .1em; text-transform: uppercase; padding: .35rem 0; border-bottom: 2px solid transparent; }
.nav a:hover { color: var(--white); border-bottom-color: var(--os2); }

/* ---------- Hero ---------- */
.hero { background: var(--rack); color: var(--on-dark); padding: clamp(2.5rem, 7vw, 5.5rem) 0 clamp(3rem, 7vw, 5.5rem); }
.hero .wrap { display: grid; grid-template-columns: minmax(0, 1.1fr) minmax(0, .9fr); gap: clamp(2rem, 5vw, 4.5rem); align-items: center; }
.hero h1 { color: var(--white); }
.hero .who { font: 600 .95rem/1.3 var(--f-head); letter-spacing: .12em; text-transform: uppercase; color: var(--os2); margin-bottom: 1rem; }
.hero .lead { font-size: 1.2rem; max-width: 34em; margin: 1.25rem 0 2rem; }
.btn {
  display: inline-block; background: linear-gradient(135deg, var(--os2), var(--os2-deep)); color: var(--rack); text-decoration: none;
  font: 700 1.05rem/1 var(--f-head); letter-spacing: .04em; padding: 1rem 1.5rem; border-radius: 0; border: 0; cursor: pointer;
}
.btn:hover { background: var(--os2-deep); color: var(--rack); }
.hero .where { margin-top: 1.5rem; font-size: .98rem; color: var(--on-dark-muted); }

/* Pile OSI : l'élément signature */
.stack { list-style: none; margin: 0; padding: 0; display: grid; gap: 6px; }
.stack li {
  display: grid; grid-template-columns: 2.6rem 1fr auto; align-items: center; gap: .75rem;
  border: 1px solid var(--rack-line); border-radius: 0; padding: .55rem .8rem; min-height: 2.9rem;
  color: #8a8a8a; font-size: .95rem;
}
.stack .n { font: 700 1.05rem/1 var(--f-head); color: #707070; }
.stack .name { font-weight: 500; }
.stack .use { font-size: .88rem; text-align: right; }
.stack li.on { border-color: var(--om3-light); color: #eef7fb; background: rgba(41, 171, 226, .08); }
.stack li.on .n { color: var(--om3-light); }
.stack li.on .use { color: #b9e1f3; }
.stack li.l4 { background: linear-gradient(135deg, var(--os2), var(--os2-deep)); border-color: var(--os2); color: var(--rack); }
.stack li.l4 .n, .stack li.l4 .use { color: var(--rack); }
.stack li.l4 .name { font-weight: 600; }
.stack-caption { font-size: .85rem; color: var(--on-dark-muted); margin-top: .8rem; }

@media (prefers-reduced-motion: no-preference) {
  .stack li { animation: rise .5s ease-out both; }
  .stack li:nth-child(1) { animation-delay: .05s; } .stack li:nth-child(2) { animation-delay: .1s; }
  .stack li:nth-child(3) { animation-delay: .15s; } .stack li:nth-child(4) { animation-delay: .3s; }
  .stack li:nth-child(5) { animation-delay: .2s; } .stack li:nth-child(6) { animation-delay: .25s; }
  .stack li:nth-child(7) { animation-delay: .3s; }
  @keyframes rise { from { opacity: 0; transform: translateX(12px); } to { opacity: 1; transform: none; } }
}

/* ---------- Faits ---------- */
.facts { background: var(--white); border-bottom: 1px solid var(--line); }
.facts ul { list-style: none; margin: 0 auto; padding-top: 1.4rem; padding-bottom: 1.4rem; display: flex; flex-wrap: wrap; gap: 1rem 3rem; }
.facts li { font-size: 1rem; color: var(--muted); display: flex; align-items: baseline; gap: .4rem; }
.facts li::before { content: ""; align-self: center; width: .5rem; height: .5rem; background: var(--os2); }
.facts li:nth-child(2)::before { background: var(--om3-light); }
.facts li:nth-child(3)::before { background: var(--green); }
.facts li:nth-child(4)::before { background: #999; }
.facts strong { font: 700 1.25rem/1 var(--f-head); color: var(--rack); }

/* ---------- Sections ---------- */
.section { padding: clamp(3.5rem, 8vw, 6rem) 0; }
.section + .section { border-top: 1px solid var(--line); }
.section-head { max-width: 40rem; margin-bottom: 2.5rem; }
.section-head p { color: var(--muted); font-size: 1.1rem; margin-top: .8rem; }

/* Expertises : trois colonnes rattachées à leur couche */
.domains { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 2.5rem; }
/* une couleur du logo par domaine : bleu L2-L3, orange L4-L7, vert L3-L7 */
.domain { border-top: 4px solid var(--om3-light); padding-top: 1.25rem; }
.domain .layers { font: 700 .95rem/1 var(--f-head); letter-spacing: .1em; color: var(--om3); margin-bottom: .6rem; display: block; }
.domain:nth-child(2) { border-top-color: var(--os2); }
.domain:nth-child(2) .layers { color: var(--os2-text); }
.domain:nth-child(3) { border-top-color: var(--green); }
.domain:nth-child(3) .layers { color: var(--green-text); }
.domain h3 { margin-bottom: .75rem; }
.domain ul { margin: 0; padding-left: 1.1rem; list-style: square; }
.domain li { margin-bottom: .4rem; }
.domain li::marker { color: var(--os2); }
.also { margin-top: 2.5rem; color: var(--muted); max-width: 48rem; }
.also strong { color: var(--ink); font-weight: 600; }

/* Interventions : liste à deux colonnes, sans cartes */
.offers { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 0 3.5rem; margin: 0; }
.offer { padding: 1.4rem 0 1.4rem 1.1rem; border-bottom: 1px solid var(--line); position: relative; }
.offer::before { content: ""; position: absolute; left: 0; top: 1.85rem; width: .45rem; height: .45rem; background: var(--os2); }
.offer dt { font: 600 1.25rem/1.2 var(--f-head); color: var(--rack); margin-bottom: .4rem; }
.offer dd { margin: 0; color: var(--ink); }

/* Références */
.cases { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 1.5rem; }
.case { background: var(--white); border: 1px solid var(--line); border-top: 4px solid var(--om3-light); padding: 1.4rem 1.4rem 1.2rem; border-radius: 0; }
.case .sector { font: 700 .9rem/1.25 var(--f-head); letter-spacing: .08em; text-transform: uppercase; color: var(--om3); display: block; margin-bottom: .6rem; }
.case p { margin: 0; }
.sectors { margin-top: 2rem; color: var(--muted); }

/* ---------- Contact ---------- */
.contact { background: var(--rack); color: var(--on-dark); }
.contact h2 { color: var(--white); }
.contact .kicker, .contact .section-head p { color: var(--on-dark-muted); }
.contact-grid { display: grid; grid-template-columns: minmax(0, 1.4fr) minmax(0, .8fr); gap: clamp(2rem, 5vw, 4rem); align-items: start; }
.form { display: grid; grid-template-columns: 1fr 1fr; gap: 1.1rem 1.25rem; }
.field { display: grid; gap: .35rem; }
.field.full { grid-column: 1 / -1; }
.field label { font-weight: 500; color: var(--white); }
.field .opt { color: var(--on-dark-muted); font-weight: 400; }
.field input, .field textarea {
  font: inherit; color: var(--ink); background: var(--white);
  border: 2px solid transparent; border-radius: 0; padding: .7rem .8rem; width: 100%;
}
.field textarea { min-height: 10rem; resize: vertical; }
.field input:focus, .field textarea:focus { outline: none; border-color: var(--os2); }
.hp { position: absolute; left: -10000px; width: 1px; height: 1px; overflow: hidden; }
.form-foot { grid-column: 1 / -1; display: flex; flex-wrap: wrap; align-items: center; gap: 1rem 1.5rem; }
.form-note { font-size: .9rem; color: var(--on-dark-muted); margin: 0; flex: 1 1 18rem; }
.form-note a, .contact-side a { color: var(--om3-light); }
.contact-side p { margin-bottom: 1.2rem; }
.contact-side strong { color: var(--white); font-weight: 600; display: block; }
noscript p { background: #fff3c4; color: var(--rack); padding: .8rem 1rem; border-radius: 0; }

/* ---------- Pied de page ---------- */
.site-foot { background: #111111; color: #9a9a9a; font-size: .92rem; border-top: 3px solid transparent; border-image: var(--brand-strip) 1; }
.site-foot .wrap { display: flex; flex-wrap: wrap; justify-content: space-between; gap: .75rem 2rem; padding-top: 1.5rem; padding-bottom: 1.5rem; }
.site-foot a { color: var(--on-dark); }
.site-foot a:hover { color: var(--white); }

/* ---------- Pages simples (mentions, merci, erreur) ---------- */
.page { padding: clamp(3rem, 7vw, 5rem) 0; }
.page .wrap { max-width: 46rem; }
.page h1 { font-size: clamp(2rem, 4.5vw, 2.8rem); margin-bottom: 1.5rem; }
.page h2 { font-size: 1.4rem; margin: 2.2rem 0 .7rem; }
.page .todo { background: #fff3c4; padding: 0 .3rem; }
.status { border-left: 4px solid var(--green); padding-left: 1.2rem; }
.status.err { border-color: var(--danger); }

/* ---------- Responsive ---------- */
@media (max-width: 60rem) {
  .hero .wrap, .contact-grid { grid-template-columns: 1fr; }
  .domains, .cases { grid-template-columns: 1fr; gap: 2rem; }
  .offers { grid-template-columns: 1fr; }
}
@media (max-width: 34rem) {
  .form { grid-template-columns: 1fr; }
  .stack .use { display: none; }
  .stack li { grid-template-columns: 2.2rem 1fr; }
}