form.mbForm { width: 700px; margin: 20px auto;}
.mbForm input, .mbForm textarea { display: block; 
  width: 100%; margin: 5px; font-size: 16px; padding: 5px; }
h1 { text-align: center; }
p { margin: 10px; }
.block { background-color: #333; color: #fff; 
  margin: 20px 0; padding: 0 10px; }
.flex-content { display: flex; align-items: flex-start; }
.content { background-color: lightgray; 
  padding: 10px; font-size: 16px; flex: 1; }
.linkbox { border: 1px solid #999; }
.linkbox:hover { background: #333; color: #fff; }