:root {
    --brand: #0d6efd; /* bootstrap primary */
    --brand-600: #0b5ed7;
    --ink: #212529;
    --muted-ink: #6c757d;
    --surface: #ffffff;
    --surface-soft: #f8f9fa;
}

html, body {
    height: 100%;
}

body {
    background: radial-gradient(1200px 600px at top left, #eef3ff 0%, #f7f9fc 40%, #ffffff 100%);
    color: var(--ink);
}

h1 {
    font-weight: 700;
    letter-spacing: -0.02em;
    margin-bottom: 0.75rem;
}

h1 + .nav-tabs { /* snug to header */
    margin-top: 0.75rem !important;
}

/* Tabs */
.nav-tabs {
    --bs-nav-tabs-border-color: rgba(13, 110, 253, .25);
}
.nav-tabs .nav-link {
    border: 1px solid transparent;
    border-radius: .5rem .5rem 0 0;
    color: var(--muted-ink);
    transition: color .15s ease, background-color .15s ease, border-color .15s ease;
    padding: 0.5rem 0.9rem;
}
.nav-tabs .nav-link:hover {
    color: var(--brand-600);
    background-color: rgba(13,110,253,.06);
}
.nav-tabs .nav-link.active {
    color: var(--brand-600);
    font-weight: 600;
    background-color: var(--surface);
    border-color: rgba(13,110,253,.35) rgba(13,110,253,.35) transparent;
}

/* Tab content card */
.tab-content {
    background: var(--surface);
    border-radius: 0 .5rem .5rem .5rem;
    box-shadow: 0 6px 18px rgba(33,37,41,.08);
}

/* Buttons spacing */
.btn { margin-right: .5rem; margin-bottom: .5rem; }

/* Ensure no gap in split buttons */
.btn-group .btn { margin-right: 0; }

/* Table tweaks */
table.table tbody tr:hover {
    background-color: rgba(13,110,253,.06);
}
table.table thead th {
    background: var(--surface-soft);
}

/* Optional callout styling if used */
.callout {
    background: linear-gradient(0deg, #fff, #fff) padding-box,
                linear-gradient(135deg, rgba(13,110,253,.35), rgba(25,135,84,.35)) border-box;
    border: 1px solid transparent;
    border-radius: .75rem;
    padding: 1rem 1.25rem;
    color: var(--ink);
    box-shadow: 0 4px 12px rgba(33,37,41,.06);
    margin: 1rem 0;
}

/* Layout niceties */
.container { margin-top: 1rem; }