.column {
    float: left;
    width: 50%;
    padding: 10px;
    height: 300px;
}
.container {
  position: relative;
}

.container img {
  width: 100%;
  height: 100%;
}

.row:after {
    content: "";
    display: table;
    clear: both;
}
* {
  box-sizing: border-box;
}

body {
  background-color: #f1f1f1;
}

#loginform ,#registerform{
  background-color: #ffffff;
  margin: 100px auto;
  font-family: Raleway;
  padding: 40px;
  width: 70%;
  min-width: 300px;
}

h4 {
  text-align: center;  
  color: black;
}

input {
  padding: 10px;
  width: 100%;
  font-size: 17px;
  font-family: Raleway;
  border: 1px solid #aaaaaa;
}
input.invalid {
  background-color: #ffdddd;
}
.tab {
  display: none;
}

button {
  background-color: #4CAF50;
  color: #ffffff;
  border: none;
  padding: 10px 20px;
  font-size: 17px;
  font-family: Raleway;
  cursor: pointer;
}

button:hover {
  opacity: 0.8;
}

body {
    margin: 0;
    font-family: Arial;
    font-size: 17px;
}

.container {
    position: relative;
    max-width: 100%;
    margin: 0 auto;
}

.container img {vertical-align: middle;}

.container .content {
    position: absolute;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    color: #f1f1f1;
    width: 100%;
    height: 100%;
    padding: 20px;
}