:root {
    --or: #ffb347;
    --rouge: #d94f2b;
    --fonce: #1a0f0a;
    --clair: #fff4e6;
  }
  * { margin: 0; padding: 0; box-sizing: border-box; }
  body {
    font-family: 'Segoe UI', Arial, sans-serif;
    background: var(--fonce);
    color: var(--clair);
    line-height: 1.7;
  }
  header {
    background: radial-gradient(circle at 30% 30%, #ffb347, #d94f2b 45%, #6b1f12 100%);
    text-align: center;
    padding: 100px 20px;
    color: #fff;
    box-shadow: inset 0 -40px 60px rgba(0,0,0,.5);
  }
  header h1 { font-size: 2.8rem; margin-bottom: 15px; text-shadow: 0 2px 8px rgba(0,0,0,.4); }
  header p { font-size: 1.3rem; max-width: 700px; margin: 0 auto; }
  .cta {
    display: inline-block;
    margin-top: 30px;
    padding: 15px 40px;
    background: #fff;
    color: var(--rouge);
    font-weight: bold;
    text-decoration: none;
    border-radius: 40px;
    transition: transform .2s;
  }
  .cta:hover { transform: scale(1.08); }
  section { max-width: 900px; margin: 0 auto; padding: 60px 25px; }
  h2 { color: var(--or); font-size: 2rem; margin-bottom: 25px; border-bottom: 2px solid var(--rouge); padding-bottom: 10px; }
  h3 { color: var(--or); margin: 25px 0 10px; }
  .grille { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px,1fr)); gap: 20px; margin: 24px 0; }
  #why > .grille { margin-top: 36px; }
  .carte {
    background: rgba(255,179,71,.08);
    border: 1px solid rgba(255,179,71,.25);
    border-radius: 12px;
    padding: 25px;
    transition: transform .2s, background .2s;
  }
  .carte:hover { transform: translateY(-5px); background: rgba(255,179,71,.15); }
  .carte .num { font-size: 2.5rem; color: var(--rouge); font-weight: bold; }
  code {
    display: block;
    background: #000;
    color: #7CFC00;
    padding: 12px;
    border-radius: 8px;
    margin: 10px 0;
    font-family: monospace;
    overflow-x: auto;
  }
  table { width: 100%; border-collapse: collapse; margin: 20px 0; }
  th, td { padding: 12px; border: 1px solid rgba(255,179,71,.3); text-align: left; }
  th { background: rgba(217,79,43,.4); color: var(--or); }
  .step { border-left: 4px solid var(--or); padding-left: 20px; margin: 20px 0; }
  footer { text-align: center; padding: 40px; background: #000; color: #aaa; }
  .avert { background: rgba(217,79,43,.15); border-left: 4px solid var(--rouge); padding: 15px 20px; border-radius: 6px; margin: 20px 0; }
  .references { margin-left: 20px; line-height: 1.9; }
  .references li { margin-bottom: 10px; }
  .formule {
    display: block;
    background: #000;
    color: #ffd27a;
    padding: 14px 18px;
    border-radius: 8px;
    margin: 12px 0;
    font-family: 'Cambria Math', Cambria, 'Segoe UI', serif;
    font-style: italic;
    overflow-x: auto;
    border-left: 3px solid var(--or);
  }
  html { scroll-behavior: smooth; }
  .lang-switch {
    position: fixed; top: 15px; right: 15px; z-index: 1000;
    display: flex; gap: 4px;
    background: rgba(26,15,10,.85);
    border: 1px solid rgba(255,179,71,.4);
    border-radius: 30px; padding: 4px;
    backdrop-filter: blur(4px);
  }
  .lang-switch button {
    border: none; background: transparent; color: var(--clair);
    font-weight: bold; font-family: inherit;
    padding: 6px 14px; border-radius: 20px; cursor: pointer;
  }
  .lang-switch button.actif { background: var(--or); color: var(--fonce); }
  .sim-controls { display: flex; align-items: center; gap: 15px; flex-wrap: wrap; margin: 20px 0; }
  .sim-controls input[type=range] { flex: 1; min-width: 200px; accent-color: var(--or); }
  #simCanvas {
    width: 100%; height: auto; background: #000;
    border: 1px solid rgba(255,179,71,.3); border-radius: 10px;
  }