body{
    background:#f5f7fb;
    font-family: 'Segoe UI', sans-serif;
}

.app-card{
    border-radius:16px;
    box-shadow:0 20px 40px rgba(0,0,0,.08);
    background:#fff;
}

.app-header{
    background:linear-gradient(135deg,#0d6efd,#0b1c2d);
    color:#fff;
    border-radius:16px 16px 0 0;
    padding:20px;
}

.btn-primary{
    border-radius:30px;
    padding:10px 30px;
}

.preview-box{
    border:2px dashed #ced4da;
    border-radius:12px;
    padding:20px;
    text-align:center;
    min-height:200px;
}
.loader-overlay{
    position:fixed;
    top:0;
    left:0;
    width:100%;
    height:100%;
    background:rgba(11,28,45,.85);
    display:none;
    align-items:center;
    justify-content:center;
    z-index:9999;
}

.loader-box{
    text-align:center;
    color:#fff;
}

.spinner-border{
    width:4rem;
    height:4rem;
}

.loader-text{
    margin-top:15px;
    font-size:16px;
    letter-spacing:.5px;
}