* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: Arial, sans-serif;
  color: #222;
  background: #fafafa;
  line-height: 1.6;
}

header {
  padding: 20px;
  background: #111;
  color: white;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

nav a {
  color: white;
  margin-left: 16px;
  text-decoration: none;
}

main {
  max-width: 1100px;
  margin: auto;
  padding: 30px 20px;
}

.hero {
  padding: 70px 20px;
  background: #e9e9e9;
  text-align: center;
  border-radius: 12px;
}

.btn {
  display: inline-block;
  margin-top: 16px;
  padding: 12px 20px;
  background: #111;
  color: white;
  text-decoration: none;
  border-radius: 6px;
}

section {
  margin: 50px 0;
}

.grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
}

.grid > div {
  background: white;
  padding: 20px;
  border: 1px solid #ddd;
  border-radius: 10px;
}

.placeholder {
  height: 220px;
  display: grid;
  place-items: center;
  background: #ddd !important;
}

footer {
  text-align: center;
  padding: 25px;
  background: #111;
  color: white;
}

@media (max-width: 768px) {
  header {
    display: block;
    text-align: center;
  }

  nav a {
    display: inline-block;
    margin: 8px;
  }

  .grid {
    grid-template-columns: 1fr;
  }
}