style.css

#message_for {
  overflow: hidden;
  background-color: #DDD;
  position: fixed;
  bottom: 0;
  width: 100%;
}

#svr-messages {
  color: red;
}

.header {
  background-color: #042037;
  color: #ffffff;
  padding: 15px;
  #max-width: 90%;
}

[class*="box-"] {
  width: 100%;
}

button {
  background-color: #c0ffee;
  color: darkslategray;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.12), 0 1px 2px rgba(0, 0, 0, 0.24);
}

img {
  max-width: 100%;
  max-height: 10%;
}

.bg {
  width: 100%;
  height: 100%;
  position: absolute;
  top: 0;
  left: 0;

  background: url("test.jpg");
  opacity: 0.5;
  background-size: auto;
  z-index: -1;
}

@media only screen and (min-width: 600px) {

  /* For tablets: */
  .header {
    width: 100%;
  }
}

@media only screen and (min-width: 768px) {

  /* For desktop: */
  .header {
    width: 100%;
  }
}