body {
  margin: 0;
  font-family: 'Segoe UI', sans-serif;
  background-color: #000;
  color: #fff;
  scroll-behavior: smooth;
}
header, section {
  padding: 4rem 1rem;
  max-width: 900px;
  margin: auto;
}
nav {
  position: sticky;
  top: 0;
  background-color: #111;
  display: flex;
  justify-content: center;
  gap: 1rem;
  padding: 1rem;
  z-index: 1000;
  border-bottom: 1px solid #222;
}
nav a {
  color: #fff;
  background-color: #045FA9;
  text-decoration: none;
  padding: 0.8rem 1.2rem;
  border-radius: 6px;
  font-weight: bold;
}
nav a:hover {
  background-color: #067bc2;
}
h1, h2 {
  color: #FFD700;
}
.btn-group {
  display: flex;
  gap: 1rem;
  margin-top: 1.5rem;
  flex-wrap: wrap;
}
.btn {
  padding: 0.8rem 1.2rem;
  text-decoration: none;
  color: white;
  border-radius: 5px;
  font-weight: bold;
}
.btn-whatsapp {
  background-color: #25D366;
}
.btn-bilan {
  background-color: #D00000;
}
footer {
  text-align: center;
  padding: 2rem 1rem;
  border-top: 1px solid #333;
  color: #aaa;
}
iframe {
  max-width: 100%;
}
input, textarea {
  width: 100%;
  max-width: 500px;
  padding: 0.8rem;
  border-radius: 6px;
  border: none;
  margin-top: 0.5rem;
  margin-bottom: 1rem;
  background-color: #222;
  color: #fff;
}
button {
  padding: 0.8rem 1.2rem;
  background-color: #D00000;
  color: #fff;
  border: none;
  border-radius: 5px;
  font-weight: bold;
}