body {
  font-family: Arial, sans-serif;
  margin: 0;
  background: #f6f7fb;
  color: #1a1a1a;
}

.hero {
  background: #1f4bd8;
  color: white;
  padding: 40px;
  text-align: center;
}

.container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 20px;
  padding: 30px;
}

.card {
  background: white;
  padding: 20px;
  border-radius: 10px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.card a {
  display: inline-block;
  margin-top: 10px;
  color: #1f4bd8;
  text-decoration: none;
  font-weight: bold;
}

footer {
  text-align: center;
  padding: 20px;
  font-size: 0.9em;
}

.box {
  padding: 15px;
  margin: 15px 0;
  border-radius: 8px;
  border-left: 5px solid;
  background: white;
}

/* Intuition */
.intuition {
  border-color: #7c4dff;
  background: #f3f0ff;
}

/* Théorie */
.theory {
  border-color: #1f4bd8;
  background: #eef3ff;
}

/* Exemple */
.example {
  border-color: #2e7d32;
  background: #edf7ee;
}

/* Erreur */
.warning {
  border-color: #d32f2f;
  background: #fff1f1;
}