/* ============================================================
   ÉTUDES · feuille partagée
   Reprend les jetons du portfolio (bleu nuit, cyan, or, Archivo).
   ============================================================ */

:root {
  color-scheme: dark;
  --ink: #081420;
  --panel: #10202f;
  --panel-light: #172a39;
  --paper: #eef4fa;
  --muted: #a5b5c3;
  --line: rgba(201, 218, 231, .19);
  --lime: #46b6c8;
  --orange: #d9b978;
  --serif: Georgia, 'Times New Roman', serif;
  --sans: 'Inter', 'Helvetica Neue', Arial, sans-serif;
  --display: 'Archivo', 'Inter', 'Helvetica Neue', Arial, sans-serif;
  --mono: 'JetBrains Mono', 'Courier New', monospace;
}

@font-face { font-family: 'Archivo'; src: url('../assets/fonts/Archivo-400-normal.woff2') format('woff2'); font-style: normal; font-weight: 600 900; font-display: swap; }
@font-face { font-family: 'Inter'; src: url('../assets/fonts/Inter-400-normal.woff2') format('woff2'); font-style: normal; font-weight: 100 900; font-display: swap; }
@font-face { font-family: 'JetBrains Mono'; src: url('../assets/fonts/JetBrainsMono-400-normal.woff2') format('woff2'); font-style: normal; font-weight: 400; font-display: swap; }

*, *::before, *::after { box-sizing: border-box; }

html { background: var(--ink); scroll-behavior: smooth; }

body {
  margin: 0;
  background:
    radial-gradient(ellipse 70% 50% at 82% -6%, rgba(38, 131, 152, .28), transparent 62%),
    radial-gradient(ellipse 60% 45% at 4% 68%, rgba(20, 62, 86, .3), transparent 66%),
    linear-gradient(178deg, #0a1826 0%, #081420 54%, #050e17 100%);
  background-attachment: fixed;
  color: var(--paper);
  font: 17px/1.8 var(--sans);
  -webkit-font-smoothing: antialiased;
}

button, input, select, textarea { font-family: inherit; }
code, kbd, samp, pre { font-family: var(--mono); }

a { color: inherit; }
a:focus-visible { outline: 2px solid var(--lime); outline-offset: 4px; }
::selection { background: var(--lime); color: var(--ink); }

.wrap { width: min(100% - 2.6rem, 700px); margin-inline: auto; }

/* ---------- barre ---------- */
.nav {
  position: sticky;
  top: 0;
  z-index: 10;
  border-bottom: 1px solid var(--line);
  background: rgba(8, 20, 32, .86);
  backdrop-filter: blur(14px);
}
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  width: min(100% - 2.6rem, 1080px);
  margin-inline: auto;
  min-height: 62px;
}
.brand {
  display: flex;
  align-items: center;
  gap: .7rem;
  font-size: .78rem;
  font-weight: 700;
  text-decoration: none;
  letter-spacing: .02em;
}
.brand-mark {
  display: grid;
  width: 26px;
  height: 26px;
  place-items: center;
  border: 1px solid var(--lime);
  border-radius: 50%;
  color: var(--lime);
  font: .64rem var(--mono);
  letter-spacing: .01em;
}
.nav-links { display: flex; align-items: center; gap: 1.1rem; }
.nav-links a {
  color: var(--muted);
  font-size: .74rem;
  text-decoration: none;
  transition: color .2s ease;
}
.nav-links a:hover { color: var(--lime); }
.nav-links .nav-cta {
  padding: .55rem .8rem;
  border: 1px solid var(--line);
  color: var(--paper);
}
.nav-links .nav-cta:hover { border-color: var(--lime); }

/* ---------- en-tête d'étude ---------- */
.study-head { padding: clamp(3rem, 7vw, 5.5rem) 0 0; }
.kicker {
  margin: 0 0 1.6rem;
  color: var(--lime);
  font: .68rem/1.6 var(--mono);
  letter-spacing: .12em;
  text-transform: uppercase;
}
h1 {
  margin: 0;
  font-family: var(--display);
  font-weight: 700;
  font-size: clamp(2.2rem, 5.6vw, 4rem);
  line-height: .98;
  letter-spacing: -.055em;
  text-wrap: balance;
}
h1 em { color: var(--orange); font-family: var(--serif); font-weight: 400; font-style: italic; letter-spacing: -.045em; }
.standfirst {
  max-width: 640px;
  margin: 1.5rem 0 0;
  color: #c1cfda;
  font-size: clamp(1rem, 1.6vw, 1.18rem);
  line-height: 1.75;
}
.meta {
  display: flex;
  flex-wrap: wrap;
  gap: .4rem 1.2rem;
  margin: 2rem 0 0;
  padding-top: 1.2rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font: .6rem/1.6 var(--mono);
  letter-spacing: .08em;
  text-transform: uppercase;
}
.meta span::before { margin-right: .55rem; color: var(--lime); content: '·'; }
.meta span:first-child::before { content: none; margin: 0; }

/* ---------- TL;DR ---------- */
.tldr {
  margin: clamp(2.4rem, 5vw, 3.6rem) 0 0;
  padding: 1.4rem 1.5rem;
  border: 1px solid rgba(70, 182, 200, .32);
  border-left: 3px solid var(--lime);
  background: linear-gradient(120deg, rgba(70, 182, 200, .1), rgba(16, 32, 47, .55));
}
.tldr-title {
  margin: 0 0 1rem;
  color: var(--lime);
  font: .62rem/1.5 var(--mono);
  letter-spacing: .11em;
  text-transform: uppercase;
}
.tldr dl { display: grid; grid-template-columns: 108px 1fr; gap: .75rem 1rem; margin: 0; }
.tldr dt {
  color: #8fa4b4;
  font: .58rem/1.8 var(--mono);
  letter-spacing: .09em;
  text-transform: uppercase;
}
.tldr dd { margin: 0; color: #dbe6ee; font-size: .92rem; line-height: 1.65; }

/* ---------- corps ---------- */
.study-body { padding: clamp(2.6rem, 5vw, 4rem) 0 0; }
section { margin: 0 0 clamp(2.6rem, 5vw, 3.8rem); }
.section-head { margin: 0 0 1.3rem; }
.section-index {
  display: block;
  margin: 0 0 .6rem;
  color: var(--lime);
  font: .6rem/1.5 var(--mono);
  letter-spacing: .12em;
  text-transform: uppercase;
}
h2 {
  margin: 0;
  font-family: var(--display);
  font-size: clamp(1.5rem, 3vw, 2.15rem);
  line-height: 1.1;
  letter-spacing: -.04em;
  font-weight: 700;
  text-wrap: balance;
}
h3 {
  margin: 2rem 0 .6rem;
  font-family: var(--display);
  font-size: 1.06rem;
  letter-spacing: -.02em;
  font-weight: 700;
}
p { margin: 0 0 1.15rem; color: #cdd9e2; }
p:last-child { margin-bottom: 0; }
strong { color: var(--paper); font-weight: 600; }
em { color: #dbe6ee; }
ul, ol { margin: 0 0 1.2rem; padding-left: 1.3rem; color: #cdd9e2; }
li { margin-bottom: .55rem; }
li::marker { color: var(--lime); }
.code { font-family: var(--mono); font-size: .86em; color: var(--paper); }

/* ---------- chiffres clés ---------- */
.stats {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 1px;
  margin: 1.8rem 0 0;
  border: 1px solid var(--line);
  background: var(--line);
}
.stat { padding: 1rem .9rem; background: #0d1c2a; }
.stat strong {
  display: block;
  font: 700 clamp(1.4rem, 2.6vw, 2rem)/1 var(--display);
  letter-spacing: -.05em;
  color: var(--paper);
  font-variant-numeric: tabular-nums;
}
.stat span {
  display: block;
  margin-top: .55rem;
  color: #93a7b9;
  font: .56rem/1.5 var(--mono);
  letter-spacing: .06em;
  text-transform: uppercase;
}

/* ---------- figures ---------- */
figure { margin: 2rem 0; }
figure img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--line);
  background: #0d1c2a;
}
figcaption {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: .4rem 1rem;
  margin-top: .7rem;
  color: #8fa4b4;
  font: .6rem/1.6 var(--mono);
  letter-spacing: .03em;
}
figcaption span:last-child { color: #7d92a2; }
/* ---------- lien d'action (démo, profil) ---------- */
.cta { margin: 2.2rem 0; }
.cta a {
  display: inline-flex;
  align-items: center;
  gap: .55rem;
  padding: .7rem .95rem;
  border: 1px solid var(--line);
  background: rgba(70, 182, 200, .09);
  color: var(--paper);
  font: .74rem/1 var(--mono);
  letter-spacing: .02em;
  text-decoration: none;
}
.cta a:hover { border-color: var(--lime); background: rgba(70, 182, 200, .18); }
html[lang="en"] .cta a[hreflang="fr"]::after {
  margin-left: .25rem;
  padding: .1rem .28rem;
  border: 1px solid rgba(217, 185, 120, .55);
  color: var(--orange);
  font: .5rem/1 var(--mono);
  letter-spacing: .09em;
  content: 'FR';
}

figure.frame iframe {
  display: block;
  width: 100%;
  height: clamp(360px, 58vh, 560px);
  border: 1px solid var(--line);
  background: #0b1621;
}
@media (min-width: 1040px) {
  figure.bleed { margin-inline: -140px; }
}

/* ---------- encadrés ---------- */
.limits {
  margin: 1.6rem 0 0;
  padding: 1.15rem 1.3rem;
  border: 1px solid rgba(217, 185, 120, .3);
  border-left: 3px solid var(--orange);
  background: rgba(217, 185, 120, .07);
}
.limits strong {
  display: block;
  margin-bottom: .5rem;
  color: var(--orange);
  font: .6rem/1.5 var(--mono);
  letter-spacing: .1em;
  text-transform: uppercase;
}
.limits p { color: #e5dcc9; font-size: .92rem; }

.decision {
  margin: 1.6rem 0 0;
  padding: 1.4rem 1.5rem;
  border: 1px solid rgba(70, 182, 200, .34);
  background: linear-gradient(140deg, rgba(70, 182, 200, .12), rgba(16, 32, 47, .6));
}
.decision p { color: #d6f0f4; }
.decision p + p { margin-top: .9rem; }

/* ---------- pied ---------- */
.study-foot {
  margin-top: clamp(2.6rem, 5vw, 4rem);
  padding: 2rem 0 3.5rem;
  border-top: 1px solid var(--line);
}
.foot-nav {
  display: flex;
  flex-wrap: wrap;
  gap: .8rem 1.6rem;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.8rem;
  font: .68rem/1.6 var(--mono);
}
.foot-nav a { color: var(--paper); text-underline-offset: 5px; text-decoration-color: rgba(238, 244, 250, .4); }
.foot-nav a:hover { color: var(--lime); }
.foot-contact {
  display: flex;
  flex-wrap: wrap;
  gap: .6rem 1.4rem;
  align-items: center;
  font: .68rem/1.6 var(--mono);
  color: var(--muted);
}
.foot-contact a { color: var(--paper); text-underline-offset: 5px; }
.foot-contact a:hover { color: var(--lime); }
.foot-note { margin: 1.4rem 0 0; color: #7d92a2; font: .6rem/1.7 var(--mono); }

/* ---------- mobile ---------- */
@media (max-width: 720px) {
  body { font-size: 16.5px; }
  .wrap { width: min(100% - 2rem, 700px); }
  .tldr dl { grid-template-columns: 1fr; gap: .3rem; }
  .tldr dt { margin-top: .5rem; }
  .stats { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .nav-links .nav-secondary { display: none; }
}

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

/* ---------- impression ---------- */
@media print {
  :root { color-scheme: light; }
  body { background: #fff; color: #101820; font-size: 11pt; }
  .nav, .foot-nav { display: none; }
  h1, h2, h3, .stat strong { color: #101820; }
  .standfirst, p, li, .tldr dd, .decision p, .limits p { color: #1b2733; }
  .tldr, .decision, .limits, figure img { background: #fff; border-color: #b9c6d1; }
  .kicker, .section-index, .tldr-title, .limits strong { color: #1b6b78; }
  a { color: #101820; text-decoration: none; }
  section { break-inside: avoid; }
}

/* ---------- bascule FR / EN ---------- */
.lang-switch {
  display: inline-flex;
  align-items: center;
  gap: .15rem;
  padding: .18rem;
  border: 1px solid var(--line);
  background: rgba(16, 32, 47, .48);
}
.lang-switch button {
  min-height: 30px;
  padding: 0 .55rem;
  border: 1px solid transparent;
  background: transparent;
  color: var(--muted);
  font: .61rem var(--mono);
  cursor: pointer;
  transition: color .2s ease, border-color .2s ease, background-color .2s ease;
}
.lang-switch button[aria-pressed="true"] {
  border-color: rgba(70, 182, 200, .45);
  background: rgba(70, 182, 200, .12);
  color: var(--paper);
}
.lang-switch button:hover { color: var(--paper); }
.lang-switch button:focus-visible { outline: 2px solid var(--lime); outline-offset: 3px; }

/* mobile : la barre doit tenir avec la bascule */
@media (max-width: 720px) {
  .nav-inner { gap: .6rem; }
  .nav-links { gap: .55rem; }
  .nav-links .nav-cta { padding: .5rem .6rem; }
}

/* ---------- lien d'évitement (comme le portfolio) ---------- */
.skip-link {
  position: absolute;
  left: -9999px;
  top: auto;
  width: 1px;
  height: 1px;
  overflow: hidden;
}
.skip-link:focus {
  position: fixed;
  z-index: 99;
  left: 1rem;
  top: 1rem;
  width: auto;
  height: auto;
  padding: .8rem 1rem;
  background: var(--lime);
  color: var(--ink);
  font: .7rem var(--mono);
  letter-spacing: .06em;
  text-transform: uppercase;
  text-decoration: none;
}
/* ---------- note de preuve : mono, comme les métadonnées ---------- */
.note.proof {
  margin: 2.2rem 0 0;
  color: #8fa4b4;
  font: .72rem/1.8 var(--mono);
}
.note.proof a {
  color: var(--paper);
  text-underline-offset: 3px;
}