*, *::before, *::after { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: system-ui, -apple-system, sans-serif;
  background: #f4f7f5;
  color: #1a2421;
  min-height: 100vh;
}

#topbar {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 16px;
  background: #0a7d4f;
  color: #fff;
  position: sticky;
  top: 0;
  z-index: 10;
}
#topbar h1 { margin: 0; font-size: 18px; font-weight: 600; }
#btn-retour {
  background: transparent;
  border: 0;
  color: #fff;
  font-size: 24px;
  cursor: pointer;
  min-width: 32px;
  min-height: 32px;
}
#btn-retour[hidden] { display: none; }

#app {
  padding: 20px 16px 40px;
  max-width: 480px;
  margin: 0 auto;
  opacity: 0;
  transform: translateY(6px);
  transition: opacity 240ms ease, transform 240ms ease;
}
#app.ecran-anime {
  opacity: 1;
  transform: translateY(0);
}
#app[data-ecran="resultat"] {
  background: linear-gradient(180deg, #eaf6ef 0%, #f4f7f5 60%);
  border-radius: 16px;
  padding: 24px 16px 32px;
}

.titre-ecran {
  font-size: 22px;
  margin: 8px 0 20px;
}

.liste-choix {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.carte-choix {
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 100%;
  min-height: 56px;
  padding: 14px 18px;
  border: 1px solid #d6e2db;
  border-radius: 12px;
  background: #fff;
  font-size: 16px;
  text-align: left;
  cursor: pointer;
}
.carte-choix:active { background: #eef5f0; }
.marque-nom { font-weight: 500; }
.marque-prix { color: #0a7d4f; font-weight: 600; }

.qte-valeur {
  font-size: 56px;
  text-align: center;
  font-weight: 700;
  color: #0a7d4f;
  margin: 24px 0 8px;
}
.qte-slider { width: 100%; margin: 16px 0 28px; }

.btn-principal, .btn-secondaire {
  display: block;
  width: 100%;
  min-height: 52px;
  border-radius: 12px;
  border: 0;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  margin-top: 16px;
}
.btn-principal { background: #0a7d4f; color: #fff; }
.btn-secondaire { background: #fff; color: #0a7d4f; border: 1px solid #0a7d4f; }

.recap {
  text-align: center;
  font-size: 16px;
  color: #4a5953;
  margin: 8px 0 20px;
}

.carte-eco {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: #fff;
  border-radius: 12px;
  padding: 16px 20px;
  margin-bottom: 12px;
  box-shadow: 0 1px 3px rgba(10,125,79,0.08);
}
.eco-libelle { color: #4a5953; }
.eco-valeur { font-size: 22px; font-weight: 700; color: #0a7d4f; }

.erreur { color: #b3261e; }

.phrase-impact {
  margin: 24px 4px 8px;
  text-align: center;
  font-size: 15px;
  color: #2d4a3d;
  font-style: italic;
  line-height: 1.4;
}

.btn-lien {
  display: block;
  width: 100%;
  margin-top: 20px;
  padding: 12px;
  background: transparent;
  border: 0;
  color: #4a5953;
  font-size: 14px;
  text-decoration: underline;
  cursor: pointer;
}

.apropos-texte {
  font-size: 15px;
  line-height: 1.55;
  color: #2d4a3d;
  margin: 0 0 16px;
}

@media (prefers-reduced-motion: reduce) {
  #app { transition: none; transform: none; }
}