styles.css

.lg {
    max-width: 740px;
    margin: 0 auto;
    padding: 15px 30px 15px 30px;
    width: 100%;
}
.xlg {
    max-width: 1280px;
    margin: 0 auto;
    padding: 15px 30px 15px 30px;
} 
.btn-center {
    width: 100%;
    text-align: center;
}
.btn-size {
    min-width: 35%;
}

.error { 
    color:red;
} 

.success {
    color:green;
}

 html {
    min-height: 100vh;
}
.vertical-center {
    margin: 0;
    position: absolute;
    top: 50%;
    -ms-transform: translateY(-50%);
    transform: translateY(-50%);
}

body {
    min-height: 100vh;
    background: rgb(2,0,36);
    background: linear-gradient(158deg, rgba(2,0,36,1) 0%, rgba(8,34,138,1) 15%, rgba(118,5,148,1) 33%, rgba(8,152,133,1) 47%, rgba(0,212,255,1) 56%, rgba(118,5,148,1) 75%, rgba(9,9,121,1) 100%, rgba(7,59,154,1) 100%);
    display: flex;
    flex-direction: column;
    justify-content: center;
}

h1 {
    color:rgb(213, 241, 0);
    font-size: 3rem;
}

h2 {
    text-align: center;
    margin-bottom: 1.5rem;
}