:root{
  --ardoise: #223A34;
  --ardoise-deep: #182922;
  --papier: #EAEEE9;
  --papier-2: #E0E5DD;
  --encre: #1C2B3A;
  --craie: #D9A441;
  --craie-deep: #B9832C;
  --brique: #B5524A;
  --sapin: #4B7A68;
  --ligne: rgba(28,43,58,0.14);
  --white: #FCFBF7;

  --font-display: "Space Grotesk", sans-serif;
  --font-body: "Literata", Georgia, serif;
  --font-mono: "JetBrains Mono", monospace;
}

*{ box-sizing: border-box; margin:0; padding:0; }
html{ scroll-behavior: smooth; }

body{
  background: var(--papier);
  color: var(--encre);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a{ color: inherit; }

.wrap{
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 28px;
}

a:focus-visible, button:focus-visible{
  outline: 2px solid var(--craie-deep);
  outline-offset: 3px;
  border-radius: 2px;
}

/* ---------- Nav ---------- */
header.site{
  position: sticky;
  top: 0;
  z-index: 40;
  background: rgba(234,238,233,0.92);
  backdrop-filter: blur(6px);
  border-bottom: 1px solid var(--ligne);
}
nav{
  display:flex;
  align-items:center;
  justify-content: space-between;
  padding: 16px 0;
}
.brand{
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.02em;
  text-decoration: none;
}
.brand span{ color: var(--craie-deep); }
.nav-links{
  display:flex;
  align-items:center;
  gap: 28px;
  list-style:none;
  font-family: var(--font-display);
  font-size: 14px;
  font-weight: 500;
}
.nav-links a{ text-decoration:none; opacity:0.85; }
.nav-links a:hover{ opacity:1; color: var(--craie-deep); }
.nav-cta{
  font-family: var(--font-display);
  font-size: 14px;
  font-weight: 600;
  background: var(--ardoise);
  color: var(--white);
  padding: 9px 16px;
  border-radius: 3px;
  text-decoration: none;
  white-space: nowrap;
}
.nav-cta:hover{ background: var(--ardoise-deep); }

/* ---------- Menu déroulant "Cours" ---------- */
.has-dropdown{ position: relative; list-style: none; }

details.dropdown{ position: relative; }

details.dropdown summary{
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  gap: 6px;
  opacity: 0.85;
}
details.dropdown summary:hover{ opacity: 1; color: var(--craie-deep); }
details.dropdown summary::-webkit-details-marker{ display: none; }

details.dropdown summary .chev{
  font-size: 11px;
  transition: transform 0.15s ease;
  color: var(--craie-deep);
}
details.dropdown[open] summary .chev{ transform: rotate(180deg); }

.dropdown-menu{
  position: absolute;
  top: calc(100% + 12px);
  left: 0;
  min-width: 190px;
  background: var(--white);
  border: 1px solid var(--ligne);
  border-radius: 6px;
  box-shadow: 0 10px 30px rgba(28,43,58,0.12);
  padding: 8px;
  list-style: none;
  z-index: 50;
}
.dropdown-menu li + li{ margin-top: 2px; }
.dropdown-menu a{
  display: block;
  padding: 9px 12px;
  border-radius: 4px;
  font-size: 14px;
  font-weight: 500;
  text-decoration: none;
  opacity: 0.9;
}
.dropdown-menu a:hover{
  background: var(--papier-2);
  opacity: 1;
  color: var(--craie-deep);
}

@media (max-width: 720px){
  .dropdown-menu{ left: auto; right: 0; }
}

/* ---------- Hero ---------- */
.hero{
  background: var(--ardoise);
  color: var(--white);
  position: relative;
  overflow: hidden;
  background-image:
    repeating-linear-gradient(0deg, rgba(255,255,255,0.045) 0 1px, transparent 1px 34px),
    repeating-linear-gradient(90deg, rgba(255,255,255,0.045) 0 1px, transparent 1px 34px);
}
.hero-inner{ padding: 96px 28px 84px; }
.hero-inner.compact{ padding: 64px 28px 56px; }
.eyebrow{
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--craie);
  margin-bottom: 18px;
  display:flex;
  align-items:center;
  gap:10px;
}
.eyebrow a{ text-decoration:none; opacity:0.75; }
.eyebrow a:hover{ opacity:1; }
.hero h1{
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(2.2rem, 5vw, 3.6rem);
  line-height: 1.08;
  letter-spacing: -0.01em;
  max-width: 15ch;
}
.hero h1.course-title{ max-width: none; font-size: clamp(1.9rem, 4vw, 2.8rem); }
.hero p.lede{
  font-family: var(--font-body);
  font-size: 19px;
  line-height: 1.6;
  max-width: 46ch;
  margin-top: 24px;
  color: rgba(252,251,247,0.86);
}
.hero-actions{ display:flex; gap: 14px; margin-top: 36px; flex-wrap: wrap; }
.btn{
  display:inline-flex;
  align-items:center;
  gap: 8px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 15px;
  padding: 13px 22px;
  border-radius: 3px;
  text-decoration:none;
  border: 1px solid transparent;
  transition: transform 0.12s ease;
}
.btn:hover{ transform: translateY(-1px); }
.btn-primary{ background: var(--craie); color: var(--ardoise-deep); }
.btn-primary:hover{ background: #E7B563; }
.btn-ghost{ border-color: rgba(252,251,247,0.35); color: var(--white); }
.btn-ghost:hover{ border-color: var(--craie); color: var(--craie); }

/* ---------- Section shared ---------- */
section{ padding: 84px 0; }
section.compact{ padding: 56px 0; }
.section-head{ margin-bottom: 44px; }
.section-head .eyebrow{ color: var(--craie-deep); }
.section-head h2{
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(1.7rem, 3vw, 2.3rem);
  letter-spacing: -0.01em;
}
.rule{ border: none; border-top: 1px solid var(--ligne); }

/* ---------- About ---------- */
.about-grid{ display:grid; grid-template-columns: 1.3fr 1fr; gap: 56px; align-items:start; }
.about-grid p{ margin-bottom: 16px; max-width: 58ch; }
.about-grid p:last-child{ margin-bottom:0; }
.credentials{
  background: var(--white);
  border: 1px solid var(--ligne);
  border-radius: 4px;
  padding: 26px 28px;
}
.credentials h3{
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--craie-deep);
  margin-bottom: 16px;
}
.credentials ul{ list-style:none; }
.credentials li{ font-size: 15px; padding: 10px 0; border-top: 1px solid var(--ligne); }
.credentials li:first-of-type{ border-top:none; padding-top:0; }

/* ---------- Course ladder (homepage) ---------- */
.ladder{ display:flex; flex-direction:column; gap: 0; }
.rung{
  display:grid;
  grid-template-columns: 160px 1fr;
  gap: 24px;
  padding: 26px 0;
  border-top: 1px solid var(--ligne);
  align-items:start;
}
.rung:last-child{ border-bottom: 1px solid var(--ligne); }
.rung-label{ font-family: var(--font-display); font-weight: 600; font-size: 15px; }
.rung-label .niveau{
  display:block;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--craie-deep);
  letter-spacing: 0.04em;
  margin-bottom: 4px;
}
.cards{ display:flex; flex-wrap: wrap; gap: 10px; }
.card{
  background: var(--white);
  border: 1px solid var(--ligne);
  border-radius: 4px;
  padding: 12px 16px;
  min-width: 170px;
  transition: border-color 0.15s ease, transform 0.15s ease;
  text-decoration: none;
  display:block;
}
.card:hover{ border-color: var(--craie-deep); transform: translateY(-2px); }
.card .code{
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 14px;
  display:flex;
  align-items:center;
  gap: 8px;
}
.dot{ width: 7px; height:7px; border-radius:50%; display:inline-block; background: var(--craie-deep); flex-shrink:0; }
.dot.phys{ background: var(--brique); }
.dot.chim{ background: var(--sapin); }
.card .desc{ font-size: 13.5px; color: rgba(28,43,58,0.72); margin-top: 6px; line-height:1.45; }
.legend{
  display:flex; gap: 22px; margin-top: 28px;
  font-family: var(--font-mono); font-size: 12.5px;
  color: rgba(28,43,58,0.72); flex-wrap: wrap;
}
.legend span{ display:flex; align-items:center; gap:7px; }

/* ---------- WeBWork / CTA band ---------- */
.cta-band{ background: var(--ardoise-deep); color: var(--white); text-align:center; }
.cta-band .eyebrow{ color: var(--craie); justify-content:center; }
.cta-band h2{
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(1.6rem, 3.4vw, 2.2rem);
  max-width: 24ch;
  margin: 0 auto 16px;
}
.cta-band p{ max-width: 48ch; margin: 0 auto 32px; color: rgba(252,251,247,0.8); font-size: 16.5px; }

/* ---------- Resource lists (course pages) ---------- */
.resource-group{ margin-bottom: 20px; }
.resource-list{ display:flex; flex-direction:column; gap: 10px; }
.resource{
  display:flex;
  align-items:center;
  gap: 14px;
  background: var(--white);
  border: 1px solid var(--ligne);
  border-radius: 4px;
  padding: 14px 18px;
  text-decoration: none;
  transition: border-color 0.15s ease, transform 0.15s ease;
}
.resource:hover{ border-color: var(--craie-deep); transform: translateX(3px); }
.resource .icon{
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 600;
  color: var(--white);
  background: var(--ardoise);
  border-radius: 3px;
  padding: 5px 8px;
  flex-shrink:0;
}
.resource.video .icon{ background: var(--brique); }
.resource.slides .icon{ background: var(--sapin); }
.resource .label{ font-family: var(--font-display); font-weight: 500; font-size: 15px; }
.resource .sub{ font-size: 13px; color: rgba(28,43,58,0.6); margin-top: 2px; }
.empty-note{
  font-family: var(--font-mono);
  font-size: 13px;
  color: rgba(28,43,58,0.5);
  border: 1px dashed var(--ligne);
  border-radius: 4px;
  padding: 16px 18px;
}


/* =========================================================
   Course cards — pages de niveau
   ========================================================= */

.course-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 24px;
  margin-top: 32px;
}

.course-card {
  display: flex;
  flex-direction: column;
  min-height: 320px;

  background: var(--white);
  border: 1px solid var(--ligne);
  border-radius: 6px;

  text-decoration: none;
  color: inherit;

  overflow: hidden;

  transition:
    border-color 0.18s ease,
    transform 0.18s ease,
    box-shadow 0.18s ease;
}

.course-card:hover {
  border-color: var(--craie-deep);
  transform: translateY(-3px);
  box-shadow: 0 10px 28px rgba(28,43,58,0.09);
}


/* ---------- En-tête de la carte ---------- */

.course-card-top {
  display: flex;
  align-items: center;
  justify-content: space-between;

  padding: 18px 22px;

  background: var(--papier-2);
  border-bottom: 1px solid var(--ligne);
}

.course-code {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 600;

  letter-spacing: 0.06em;
  text-transform: uppercase;

  color: var(--ardoise);
}

.course-arrow {
  display: flex;
  align-items: center;
  justify-content: center;

  width: 30px;
  height: 30px;

  border: 1px solid var(--ligne);
  border-radius: 50%;

  font-family: var(--font-display);
  font-size: 15px;

  background: var(--white);

  transition:
    transform 0.18s ease,
    background 0.18s ease;
}

.course-card:hover .course-arrow {
  transform: translateX(4px);
  background: var(--papier);
}


/* ---------- Contenu ---------- */

.course-card-body {
  flex: 1;
  padding: 26px 24px 22px;
}

.course-card-body h3 {
  margin: 0 0 14px;

  font-family: var(--font-display);
  font-size: 1.4rem;
  font-weight: 600;
  line-height: 1.2;

  color: var(--encre);
}

.course-card-body p {
  margin: 0;

  max-width: 52ch;

  font-family: var(--font-body);
  font-size: 14.5px;
  line-height: 1.65;

  color: rgba(28,43,58,0.72);
}


/* ---------- Ressources ---------- */

.course-card-footer {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;

  padding: 16px 22px;

  border-top: 1px solid var(--ligne);
}

.course-card-footer span {
  padding: 5px 8px;

  border: 1px solid var(--ligne);
  border-radius: 3px;

  background: var(--papier);

  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.03em;
  text-transform: uppercase;

  color: rgba(28,43,58,0.65);
}


/* ---------- Animation ---------- */

.course-card.reveal {
  opacity: 0;
  transform: translateY(14px);
}

.course-card.reveal.in {
  opacity: 1;
  transform: none;
}


/* ---------- Mobile ---------- */

@media (max-width: 720px) {

  .course-grid {
    grid-template-columns: 1fr;
    gap: 18px;
  }

  .course-card {
    min-height: 280px;
  }

  .course-card-body {
    padding: 24px 20px 20px;
  }

  .course-card-body h3 {
    font-size: 1.3rem;
  }

  .course-card-footer {
    padding: 14px 20px;
  }

}

/* ---------- Footer ---------- */
footer{ padding: 48px 0 60px; font-size: 14px; color: rgba(28,43,58,0.65); }
.footer-grid{ display:flex; justify-content: space-between; align-items:flex-end; flex-wrap: wrap; gap: 20px; }
footer .brand-mono{ font-family: var(--font-mono); font-size: 13px; }
footer a{ text-decoration: underline; text-decoration-color: var(--ligne); }
footer a:hover{ text-decoration-color: var(--craie-deep); }

/* ---------- Reveal on scroll ---------- */
.reveal{ opacity: 0; transform: translateY(14px); transition: opacity 0.5s ease, transform 0.5s ease; }
.reveal.in{ opacity:1; transform:none; }

@media (prefers-reduced-motion: reduce){
  html{ scroll-behavior:auto; }
  .reveal{ opacity:1; transform:none; transition:none; }
  .btn:hover, .card:hover, .resource:hover{ transform:none; }
}

@media (max-width: 720px){
  .about-grid{ grid-template-columns: 1fr; }
  .rung{ grid-template-columns: 1fr; gap: 10px; }
  .hero-inner{ padding: 72px 20px 60px; }
  .hero-inner.compact{ padding: 56px 20px 44px; }
  section{ padding: 60px 0; }
}

/* ---------- Course description ---------- */
.hero p.course-description{
font-family: var(--font-body);
font-size: 16px;
line-height: 1.65;
max-width: 68ch;
margin-top: 18px;
color: rgba(252,251,247,0.78);
}

/* =========================
CONTACT
========================= */

.contact-section {
padding: 80px 0 100px;
}

.contact-card {
position: relative;
display: flex;
align-items: center;
justify-content: space-between;
gap: 50px;
padding: 48px 52px;
border: 1px solid rgba(0, 0, 0, 0.10);
border-radius: 18px;
background: linear-gradient(
135deg,
rgba(245, 245, 240, 0.95),
rgba(255, 255, 255, 0.98)
);
overflow: hidden;
}

.contact-content {
max-width: 650px;
position: relative;
z-index: 1;
}

.contact-content h2 {
margin: 8px 0 14px;
}

.contact-content p {
margin: 0 0 26px;
max-width: 600px;
line-height: 1.7;
}

.contact-mark {
display: flex;
align-items: center;
justify-content: center;
width: 130px;
height: 130px;
flex-shrink: 0;
border: 1px solid rgba(0, 0, 0, 0.10);
border-radius: 50%;
font-family: "JetBrains Mono", monospace;
font-size: 4rem;
font-weight: 500;
opacity: 0.12;
transform: rotate(-8deg);
}

.contact-mark::before,
.contact-mark::after {
content: "";
position: absolute;
border: 1px solid rgba(0, 0, 0, 0.08);
border-radius: 50%;
}

.contact-mark::before {
width: 170px;
height: 170px;
}

.contact-mark::after {
width: 210px;
height: 210px;
}

/* Adaptation mobile */

@media (max-width: 700px) {
.contact-section {
padding: 60px 0 75px;
}

.contact-card {
padding: 36px 28px;
}

.contact-mark {
display: none;
}
}

.site-footer {
    text-align: center;
    padding: 2rem 1rem;
    margin-top: 4rem;
    color: #666;
    font-size: 0.9rem;
    border-top: 1px solid #ddd;
}