:root{
    --primary:#4f46e5; /* indigo-600 */
    --primary-dark:#3730a3;
    --muted:#6b7280;
    --card-bg:#ffffff;
    --bg:#f3f4f6;
}
/* Global page improvements */
body{
    background-color:var(--bg) !important;
    color:#111827;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial;
}
.header-section{
    background: linear-gradient(135deg,var(--primary) 0%, var(--primary-dark) 100%);
    color: #fff;
    padding: 28px 0;
    margin-bottom: 28px;
    border-radius: 10px;
    box-shadow: 0 6px 20px rgba(15,23,42,0.08);
}
.card{
    border-radius: 12px;
    box-shadow: 0 6px 18px rgba(15,23,42,0.06);
}
.card .card-header{background:transparent;border-bottom:0;padding-bottom:0}
.card-statistic{padding:22px}
.card-statistic .icon{opacity:0.95}
.nav-pills{margin-bottom:18px}
.nav-pills .nav-link{color:var(--muted);background:transparent;border-radius:8px;padding:8px 12px;margin-right:8px}
.nav-pills .nav-link.active{background:linear-gradient(90deg,var(--primary),var(--primary-dark));color:#fff}
.user-info{color:#fff;text-align:right}
.user-info .btn{border-radius:8px}
.filter-card{padding:0}
.filter-card .card-header{border-top-left-radius:12px;border-top-right-radius:12px}
.table-container{background:var(--card-bg);padding:18px;border-radius:12px}
table.dataTable thead th{background:#111827;color:#fff;border-bottom:none}
table.table-striped>tbody>tr:nth-of-type(odd){background: #fbfbff}
.btn-action{margin:2px}
/* make modals slightly rounded */
.modal-content{border-radius:12px}
/* responsive canvas container */
#lulusChart{width:100%;height:420px}

/* small helpers */
.muted-small{color:var(--muted);font-size:0.9rem}