body {
  margin: 0;
  font-family: Arial, sans-serif;
  background-color: #f5f5f5;
}

img {
  image-rendering: pixelated;
  image-rendering: -moz-crisp-edges; /* Firefox */
  image-rendering: -o-crisp-edges;   /* Opera */
  image-rendering: -webkit-optimize-contrast; /* WebKit */
  -ms-interpolation-mode: nearest-neighbor; /* IE */
} 

.site-header {
  position: sticky;
  top: 0;
  left: 0;
  width: 100%;
  background-color: lightgray;
  padding-top: 20px;
  padding-bottom: 10px;
  text-align: center;
  display: flex;
  flex-direction: column;
  z-index: 1000;
}

.site-header-navigation-list {
  display: flex;
  flex-direction: row;
  list-style: none;
  justify-content: center;
  padding-right: 25%;
  padding-left: 25%;
}

.site-header-navigation-list-item {
  flex: 1 1 0;
}

.button {
  font: bold 14px Arial;
  text-decoration: none;
  background-color: #EEEEEE;
  color: #333333;
  padding: 2px 6px 2px 6px;
  border-top: 1px solid #CCCCCC;
  border-right: 1px solid #333333;
  border-bottom: 1px solid #333333;
  border-left: 1px solid #CCCCCC;
} 

.content {
  padding: 20px;
}

/* Example responsive layout */
@media (max-width: 600px) {
  header {
    font-size: 1.2em;
  }
}