body {
  font-family: Tahoma, sans-serif;
  margin: 0; padding: 0;
  text-align: center;
  background: #f9f9f9;
  color: #333;
}
header { background: #4CAF50; padding: 1rem; color: #fff; }
.hero { padding: 2rem; }
.buttons { margin: 1.5rem 0; }
.download-btn {
  display: inline-block;
  margin: 0.5rem;
  padding: 0.75rem 1.5rem;
  border-radius: 8px;
  text-decoration: none;
  color: #fff;
  background: #4CAF50;
}
.download-btn.disabled { background: #999; pointer-events: none; }
.slider { position: relative; max-width: 600px; margin: auto; }
.slides img { width: 100%; display: none; }
.slides img.active { display: block; }
.prev, .next {
  cursor: pointer;
  position: absolute;
  top: 50%; transform: translateY(-50%);
  padding: 0.5rem 1rem;
  background: rgba(0,0,0,0.5); color: #fff;
  border: none; border-radius: 5px;
}
.prev { left: 10px; } .next { right: 10px; }
footer { background: #333; color: #fff; padding: 1rem; margin-top: 2rem; }
footer a { color: #4CAF50; margin: 0 5px; }