body {
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  margin: 0;
  padding: 0;
  background: #f8fbff;
  color: #222;
  line-height: 1.7;
}

header {
  background: #2798f5;
  color: #fff;
  text-align: center;
  padding: 2rem 1rem;
  box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}

header h1 {
  margin: 0;
  font-size: 1.8rem;
}

.lang-switch {
  margin-top: 1rem;
}

.lang-switch button {
  background: #fff;
  color: #2798f5;
  border: none;
  padding: 0.6rem 1.2rem;
  margin: 0 0.3rem;
  border-radius: 6px;
  cursor: pointer;
  font-weight: bold;
  
  transition: all 0.3s ease;
}

.lang-switch button:hover {
  background: #eaf5ff;
  color: #13578f;
}

main {
  max-width: 900px;
  margin: 2rem auto;
  padding: 0 1rem;
}

h2 {
  color: #2798f5;
  margin-bottom: 1rem;
}

h3 {
  margin-top: 2rem;
  color: #444;
}

h4 {
  margin-top: 1.2rem;
  color: #333;
}

ul {
  padding-left: 1.3rem;
}

a {
  color: #2798f5;
  text-decoration: none;
  font-weight: bold;
}

a:hover {
  text-decoration: underline;
}

.lang {
  display: none;
}

.lang.active {
  display: block;
}

@media (max-width: 600px) {
  header h1 {
    font-size: 1.3rem;
  }
  main {
    font-size: 0.95rem;
  }
}