:root {
  --yisin-navy-950: #07152f;
  --yisin-navy-900: #0b1f45;
  --yisin-navy-800: #102b5c;
  --yisin-blue-700: #173d78;
  --yisin-blue-500: #2f5f9f;
  --yisin-gold-600: #b98222;
  --yisin-gold-500: #d6a13e;
  --yisin-gold-300: #e8c477;
  --yisin-ivory: #f8f5ee;
  --yisin-paper: #fffdf9;
  --yisin-ink: #14213a;
  --yisin-muted: #61708a;
  --md-primary-fg-color: var(--yisin-navy-900);
  --md-accent-fg-color: var(--yisin-gold-600);
}

html { scroll-behavior: smooth; }

body {
  color: var(--yisin-ink);
  background:
    radial-gradient(circle at 10% 8%, rgba(214, 161, 62, 0.07), transparent 22rem),
    var(--yisin-paper);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

.md-header,
.md-tabs {
  background: var(--yisin-navy-950);
}

.md-header {
  box-shadow: 0 1px 0 rgba(232, 196, 119, 0.25);
}

.md-tabs__link--active,
.md-tabs__link:hover,
.md-header__button:hover { color: var(--yisin-gold-300); }

.md-main__inner { margin-top: 1.4rem; }

.md-typeset h1,
.md-typeset h2,
.md-typeset h3 {
  color: var(--yisin-navy-950);
  font-family: Georgia, "Times New Roman", serif;
  letter-spacing: -0.025em;
}

.md-typeset h1 { font-size: clamp(2.1rem, 5vw, 3.5rem); font-weight: 500; }
.md-typeset h2 { margin-top: 2.6em; font-weight: 500; }
.md-typeset h3 { font-weight: 600; }
.md-typeset a { color: var(--yisin-blue-700); }
.md-typeset a:hover { color: var(--yisin-gold-600); }
.md-typeset code { border-radius: 0.25rem; }

.md-typeset blockquote {
  border-left: 3px solid var(--yisin-gold-500);
  color: var(--yisin-navy-800);
}

.md-typeset table:not([class]) {
  overflow: hidden;
  border: 1px solid rgba(16, 43, 92, 0.12);
  border-radius: 0.55rem;
  box-shadow: none;
}

.md-typeset table:not([class]) th {
  color: white;
  background: var(--yisin-navy-900);
}

.md-typeset .admonition,
.md-typeset details {
  border-width: 0 0 0 4px;
  border-radius: 0.2rem 0.6rem 0.6rem 0.2rem;
  box-shadow: 0 0.4rem 1.4rem rgba(7, 21, 47, 0.07);
}

/* Accueil éditorial */
.yisin-home { margin-top: -1.4rem; }

.hero-shell {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1.25fr) minmax(16rem, 0.75fr);
  gap: clamp(2rem, 7vw, 6rem);
  align-items: center;
  margin: 0 calc(50% - 50vw) 0;
  padding: clamp(4rem, 9vw, 8rem) max(1.2rem, calc((100vw - 61rem) / 2));
  color: white;
  background:
    radial-gradient(circle at 80% 20%, rgba(47, 95, 159, 0.48), transparent 30rem),
    linear-gradient(135deg, var(--yisin-navy-950), var(--yisin-navy-800));
  overflow: hidden;
}

.hero-shell::after {
  position: absolute;
  right: -8rem;
  bottom: -11rem;
  width: 27rem;
  height: 27rem;
  border: 1px solid rgba(232, 196, 119, 0.18);
  border-radius: 50%;
  content: "";
}

.hero-copy { position: relative; z-index: 1; }

.eyebrow {
  margin: 0 0 1.2rem;
  color: var(--yisin-gold-300);
  font-size: 0.72rem;
  font-weight: 750;
  letter-spacing: 0.17em;
  text-transform: uppercase;
}

.hero-shell h1 {
  max-width: 15ch;
  margin: 0;
  color: white;
  font-size: clamp(2.8rem, 7vw, 5.7rem);
  font-weight: 400;
  line-height: 0.98;
}

.hero-shell h1 em { color: var(--yisin-gold-300); font-style: normal; }

.hero-lead {
  max-width: 39rem;
  margin: 1.8rem 0;
  color: #dce6f6;
  font-size: clamp(1rem, 2vw, 1.2rem);
  line-height: 1.75;
}

.hero-actions { display: flex; flex-wrap: wrap; gap: 0.75rem; }

.hero-actions a {
  display: inline-flex;
  padding: 0.72rem 1.1rem;
  border: 1px solid var(--yisin-gold-500);
  border-radius: 99rem;
  color: var(--yisin-navy-950);
  background: var(--yisin-gold-300);
  font-size: 0.82rem;
  font-weight: 750;
}

.hero-actions a:last-child { color: white; background: transparent; }
.hero-actions a:hover { color: white; background: var(--yisin-gold-600); }

.hero-proof {
  position: relative;
  z-index: 1;
  padding: 1.35rem;
  border: 1px solid rgba(232, 196, 119, 0.3);
  border-radius: 1rem;
  background: rgba(7, 21, 47, 0.65);
  box-shadow: 0 1.5rem 4rem rgba(0, 0, 0, 0.22);
  backdrop-filter: blur(12px);
}

.proof-label {
  display: block;
  margin-bottom: 0.7rem;
  color: var(--yisin-gold-300);
  font-size: 0.66rem;
  font-weight: 800;
  letter-spacing: 0.13em;
  text-transform: uppercase;
}

.proof-question { margin: 0 0 1rem; color: white; font-family: Georgia, serif; font-size: 1.13rem; }
.proof-answer { padding-top: 1rem; border-top: 1px solid rgba(255,255,255,.12); color: #c8d5e9; font-size: 0.78rem; }
.proof-source { display: inline-block; margin-top: 0.7rem; color: var(--yisin-gold-300); font-size: 0.69rem; }

.metric-ribbon {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  margin: 0 calc(50% - 50vw) 0;
  padding: 0 max(1.2rem, calc((100vw - 61rem) / 2));
  color: white;
  background: var(--yisin-navy-950);
}

.metric-ribbon div { padding: 1.3rem 1rem; border-top: 1px solid rgba(232, 196, 119, .22); }
.metric-ribbon strong { display: block; color: var(--yisin-gold-300); font-family: Georgia, serif; font-size: 1.55rem; font-weight: 400; }
.metric-ribbon span { color: #aebbd0; font-size: 0.7rem; }

.home-section { padding: clamp(3.5rem, 8vw, 6rem) 0 0; }
.home-intro { display: grid; grid-template-columns: .65fr 1.35fr; gap: 3rem; align-items: start; }
.home-intro h2 { margin: 0; font-size: clamp(2rem, 4vw, 3.1rem); }
.home-intro p { margin-top: 0; color: var(--yisin-muted); font-size: 1.05rem; line-height: 1.8; }

.chapter-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 1rem; margin-top: 2.5rem; }
.chapter-card {
  position: relative;
  min-height: 13rem;
  padding: 1.45rem;
  border: 1px solid rgba(16, 43, 92, 0.12);
  border-radius: 0.8rem;
  background: rgba(255,255,255,.72);
  box-shadow: 0 .8rem 2.5rem rgba(7,21,47,.05);
  transition: transform .2s ease, border-color .2s ease;
}
.chapter-card:hover { border-color: var(--yisin-gold-500); transform: translateY(-3px); }
.chapter-number { color: var(--yisin-gold-600); font-size: .68rem; font-weight: 800; letter-spacing: .15em; }
.chapter-card h3 { margin: .7rem 0 .5rem; font-size: 1.35rem; }
.chapter-card p { color: var(--yisin-muted); }
.chapter-card a { position: absolute; bottom: 1.3rem; font-size: .78rem; font-weight: 750; }

.pipeline { display: grid; grid-template-columns: repeat(5, 1fr); gap: .55rem; margin-top: 2rem; }
.pipeline-step { position: relative; padding: 1rem .75rem; border-radius: .55rem; color: white; background: var(--yisin-navy-900); text-align: center; }
.pipeline-step:not(:last-child)::after { position: absolute; z-index: 1; top: 50%; right: -.55rem; color: var(--yisin-gold-300); content: "→"; transform: translateY(-50%); }
.pipeline-step strong, .pipeline-step span { display: block; }
.pipeline-step strong { font-family: Georgia, serif; font-size: 1rem; }
.pipeline-step span { margin-top: .25rem; color: #b9c7dc; font-size: .65rem; }

.now-grid { display: grid; grid-template-columns: .8fr 1.2fr; gap: 2rem; align-items: start; }
.now-grid h2 { margin-top: 0; }
.now-list { margin: 0; padding: 0; list-style: none; }
.now-list li { display: grid; grid-template-columns: 8rem 1fr; gap: 1rem; padding: 1rem 0; border-bottom: 1px solid rgba(16,43,92,.12); }
.now-list strong { color: var(--yisin-navy-800); }
.now-list span { color: var(--yisin-muted); }

.principle-banner { margin: 5rem calc(50% - 50vw) 0; padding: 4rem max(1.2rem, calc((100vw - 61rem) / 2)); color: white; background: var(--yisin-blue-700); text-align: center; }
.principle-banner p { max-width: 25ch; margin: 0 auto; color: white; font-family: Georgia, serif; font-size: clamp(1.8rem, 4vw, 3rem); line-height: 1.25; }
.principle-banner span { display: block; margin-top: 1rem; color: var(--yisin-gold-300); font-size: .72rem; letter-spacing: .12em; text-transform: uppercase; }

/* Composants des chapitres */
.page-lead { max-width: 46rem; margin: -1rem 0 2.5rem; color: var(--yisin-muted); font-size: 1.08rem; line-height: 1.75; }
.fact-grid, .concept-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(12rem, 1fr)); gap: .8rem; margin: 1.5rem 0 2.5rem; }
.fact-card, .concept-card { padding: 1.1rem; border: 1px solid rgba(16,43,92,.12); border-radius: .65rem; background: white; }
.fact-card strong { display: block; color: var(--yisin-blue-700); font-family: Georgia, serif; font-size: 1.55rem; }
.fact-card span { color: var(--yisin-muted); font-size: .75rem; }
.concept-card h3 { margin: 0 0 .45rem; font-size: 1rem; }
.concept-card p { margin: 0; color: var(--yisin-muted); font-size: .82rem; }
.status-pill { display: inline-block; padding: .18rem .55rem; border-radius: 99rem; color: var(--yisin-navy-900); background: rgba(214,161,62,.23); font-size: .68rem; font-weight: 750; }

@media screen and (max-width: 60em) {
  .hero-shell { grid-template-columns: 1fr; }
  .hero-proof { max-width: 30rem; }
  .metric-ribbon { grid-template-columns: repeat(2, 1fr); }
  .home-intro, .now-grid { grid-template-columns: 1fr; gap: 1rem; }
  .pipeline { grid-template-columns: 1fr; }
  .pipeline-step:not(:last-child)::after { top: auto; right: 50%; bottom: -.75rem; transform: rotate(90deg); }
}

@media screen and (max-width: 38em) {
  .hero-shell h1 { font-size: 2.65rem; }
  .chapter-grid { grid-template-columns: 1fr; }
  .metric-ribbon { grid-template-columns: 1fr 1fr; }
  .metric-ribbon div { padding-left: .35rem; }
  .now-list li { grid-template-columns: 1fr; gap: .2rem; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .chapter-card { transition: none; }
}