* {box-sizing: border-box;}

html, body {width: 100vw; min-height: 100vh;}
  
body {
  display: flex;
  flex-direction: column;
  font-family: sans-serif;
  margin: 0;
}

.content {
  flex: content;
  padding: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
}

.txtcenter {text-align: center;}

.imgcenter {
  display: block;
  margin-left: auto;
  margin-right: auto;
}

.txtbg {
  background-color: rgba(128, 128, 128, 0.5);
  border-radius: 15px;
  padding: 50px;
  }

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