* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Segoe UI", sans-serif;
}

body {
  background: #f3f3f3;
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100vh;
  text-align: center;
  padding: 20px;
}

.container {
  max-width: 600px;
  animation: fadeIn 0.8s ease;
}

.error-code {
  font-size: 140px;
  font-weight: 700;
  color: #444;
  letter-spacing: -4px;
  line-height: 1;
}

h1 {
  font-size: 32px;
  margin-bottom: 10px;
  color: #222;
}

p {
  font-size: 18px;
  margin-bottom: 25px;
  color: #555;
}

.home-btn {
  display: inline-block;
  padding: 12px 28px;
  background: #333;
  color: #fff;
  text-decoration: none;
  border-radius: 6px;
  transition: 0.25s;
}

.home-btn:hover {
  background: #555;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(20px); }
  to   { opacity: 1; transform: translateY(0); }
}