html, body
{
    height: 100%;
}

#bg {
  position: fixed; 
  top: -50%; 
  left: -50%; 
  width: 200%; 
  height: 200%;
}
#bg img {
  position: absolute; 
  top: 0; 
  left: 0; 
  right: 0; 
  bottom: 0; 
  margin: auto; 
  min-width: 50%;
  min-height: 50%;
}

.login .brand-logo {
    display: inline-block;
    overflow: hidden;
    margin: 20px 10px 10px;
  }
  .login .brand-logo img {
    width: 100%;
  }
  .login .brand-logo i {
    font-size: 30px;
    color: #6e7882;
    vertical-align: middle;
  }
  @media (min-width: 768px) {
    .login .brand-logo {
      margin: 40px 10px 0;
    }
    .login .brand-logo i {
      font-size: 60px;
    }
  }

  .login h3{
      color:#FFF;
      text-shadow: 4px 4px 2px rgb(22, 22, 22);
  }

  .login .panel-login{
    background-color: #222;  
    box-shadow: 5px 5px 8px #000;
  }

  .input-group-addon {
    background-color: #000;
    border: 1px solid #000;
    color: #CC1F26;
  }

  .login .btn-login{
    background-color:#CC1F26;
    color: #FFF;
  }

  .mensaje-alerta{
    width: 380px !important;
    margin: 0 auto;
    margin-bottom: 10px;
  }

  .btn-link, .btn-link:hover {
    color: #FFF !important;
    text-decoration: none !important;
  }

  #contenedor_principal {
    position: relative;
    background-color: black;
    height: 100%;
    width: 100%;
    overflow: hidden;
  }
  
  #contenedor_principal video {
    position: absolute;
    top: 50%;
    left: 50%;
    min-width: 100%;
    min-height: 100%;
    width: auto;
    height: auto;
    z-index: 0;
    -ms-transform: translateX(-50%) translateY(-50%);
    -moz-transform: translateX(-50%) translateY(-50%);
    -webkit-transform: translateX(-50%) translateY(-50%);
    transform: translateX(-50%) translateY(-50%);
  }

  #contenedor_principal .container {
    position: relative;
    z-index: 2;
    vertical-align: middle;
    display: table;
  }
  
  #contenedor_principal .overlay {
    position: absolute;
    top: 0;
    left: 0;
    height: 100%;
    width: 100%;
    background-image: url(data:image/png;base64,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); 
    background-size: 3px 3px;
    opacity: 0.8;
    z-index: 1;
  }

  @media (pointer: coarse) and (hover: none) {
    #contenedor_principal {
      background: url('https://source.unsplash.com/XT5OInaElMw/1600x900') black no-repeat center center scroll;
    }
    #contenedor_principal video {
      display: none;
    }
  }