/* Reset */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html, body {
  height: 100%;
  width: 100%;
  font-family: Arial, sans-serif;
  background: #f4f4f4;
}

a { text-decoration: none; color: inherit; }

header {
  background: #222;
  padding: 15px 0;
  width: 100%;
}
nav ul {
  list-style: none;
  display: flex;
  justify-content: center;
}
nav ul li { margin: 0 15px; }
nav ul li a { color: #fff; font-weight: bold; }
nav ul li a:hover { color: #4da3ff; }

.main-wrapper {
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: calc(100vh - 60px);
  width: 100%;
}

.container {
  max-width: 900px;
  padding: 30px;
  background: #fff;
  border-radius: 10px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
  text-align: center;
}

h1, h2 { margin-bottom: 20px; }
.section { margin-bottom: 30px; }

.btn {
  display: inline-block;
  margin-top: 12px;
  padding: 12px 20px;
  background: #1e88e5;
  color: #fff;
  border-radius: 6px;
  font-weight: bold;
  font-size: 16px;
}
.btn:hover { background: #1565c0; }

img {
  max-width: 100%;
  height: auto;
  display: block;
}