html,
body {
    height: 100%;
}

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;
}

.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;
        }

.taikhoan {
    margin-bottom: 10px;
    /*border-bottom-right-radius: 0;
    border-bottom-left-radius: 0;*/
}

.matkhau {
    margin-bottom: 10px;
    /*border-top-left-radius: 0;
    border-top-right-radius: 0;*/
}

.show-hide {
    position: absolute;
    right: 15px;
    top: 12px;
    z-index: 10000;
}

.main {
    position: relative;
    height: 100vh;
    width: 100vw;
    overflow: hidden;
}

.video {
    position: absolute;
    left: 0;
    top: 0;
    min-width: 100vw;
    min-height: 100vh;
}

.box {
    position: absolute;
    width: 330px;
    font-family: Helvetica;
    color: #fff;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    box-shadow: 5px 3px 30px black;
    border-radius: 10px;
    background: hsla(0,0%,100%,.3);
    line-height: 1.5;
}