html, body {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

body {
  display: -ms-flexbox;
  display: -webkit-box;
  display: flex;
  -ms-flex-align: center;
  -ms-flex-pack: center;
  -webkit-box-align: center;
  align-items: center;
  -webkit-box-pack: center;
  justify-content: center;
  padding-top: 40px;
  padding-bottom: 40px;
  background-color: #f5f5f5;
}

body:after{
  content : "";
  display: block;
  position: absolute;
  top: 0;
  left: 0;
  background-color:#f5f5f5;
  width: 100%;
  height: 100%;
  opacity : 0.4; 
  z-index: -1;
  background-repeat: no-repeat, repeat;
  background-position: center;
}


.form-signin {
  width: 100%;
  max-width: 330px;
  padding: 15px;
  margin: 0 auto;
}
.form-signin .checkbox {
  font-weight: 400;
}
.form-signin .form-control {
  position: relative;
  box-sizing: border-box;
  height: auto;
  padding: 10px;
  font-size: 16px;
}
.form-signin .form-control:focus {
  z-index: 2;
}
.form-signin input[type="email"] {
  margin-bottom: -1px;
  border-bottom-right-radius: 0;
  border-bottom-left-radius: 0;
}
.form-signin input[type="password"] {
  margin-bottom: 10px;
  border-top-left-radius: 0;
  border-top-right-radius: 0;
}