input:invalid:focus {
    border: 2px solid red;
}

#vs-loading {
    position: fixed;
    top:0;
    left:0;
    width:100%;
    height:100%;
    z-index:9999;
}

.vs-loading-overlay {
    position:absolute;
    width:100%;
    height:100%;
    background:rgba(0,0,0,0.6);
}

.vs-loading-box {
    position:absolute;
    top:50%;
    left:50%;
    transform:translate(-50%, -50%);
    background:#fff;
    padding:30px;
    border-radius:10px;
    text-align:center;
    box-shadow:0 10px 30px rgba(0,0,0,0.2);
}

.vs-spinner {
    width:50px;
    height:50px;
    border:5px solid #eee;
    border-top:5px solid #0073aa;
    border-radius:50%;
    animation:vs-spin 1s linear infinite;
    margin:0 auto 15px;
}

@keyframes vs-spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}