:root {
    --sidebar-width: 280px;
    --app-bg: #f4f7fb;
    --card-border: #e8edf5;
    --primary: #2563eb;
    --text-dark: #172033;
    --text-muted: #667085;
}

body {
    background: var(--app-bg);
    color: var(--text-dark);
    font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

.app-shell {
    min-height: 100vh;
    padding-left: var(--sidebar-width);
}

.app-sidebar {
    position: fixed;
    top: 0;
    left: 0;
    width: var(--sidebar-width);
    height: 100vh;
    background: #0f172a;
    color: #fff;
    padding: 20px;
    z-index: 1040;
    transition: transform .2s ease;
}

.sidebar-brand {
    display: flex;
    align-items: center;
    gap: 12px;
    padding-bottom: 24px;
    border-bottom: 1px solid rgba(255,255,255,.1);
    margin-bottom: 18px;
}

.brand-icon {
    width: 42px;
    height: 42px;
    border-radius: 14px;
    display: grid;
    place-items: center;
    background: var(--primary);
    font-size: 20px;
}

.sidebar-brand span,
.topbar-user small {
    display: block;
    font-size: 12px;
    color: #98a2b3;
}

.sidebar-nav a {
    display: flex;
    align-items: center;
    gap: 10px;
    color: #cbd5e1;
    text-decoration: none;
    padding: 11px 12px;
    border-radius: 12px;
    margin-bottom: 6px;
    font-weight: 500;
}

.sidebar-nav a:hover,
.sidebar-nav a.active {
    background: rgba(37, 99, 235, .18);
    color: #fff;
}

.app-topbar {
    min-height: 84px;
    background: #fff;
    border-bottom: 1px solid var(--card-border);
    padding: 18px 28px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    position: sticky;
    top: 0;
    z-index: 1020;
}

.app-topbar h1 {
    font-size: 22px;
    margin: 0;
    font-weight: 750;
}

.app-topbar p {
    margin: 4px 0 0;
    color: var(--text-muted);
    font-size: 14px;
}

.topbar-user {
    display: flex;
    align-items: center;
    gap: 10px;
}

.user-avatar {
    width: 38px;
    height: 38px;
    border-radius: 50%;
    background: #e0ecff;
    color: var(--primary);
    display: grid;
    place-items: center;
    font-weight: 800;
}

.app-main {
    padding: 28px;
}

.stat-card,
.panel-card {
    background: #fff;
    border: 1px solid var(--card-border);
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(15, 23, 42, .04);
}

.stat-card {
    padding: 20px;
}

.stat-card .icon {
    width: 42px;
    height: 42px;
    border-radius: 14px;
    display: grid;
    place-items: center;
    background: #eef4ff;
    color: var(--primary);
    margin-bottom: 14px;
}

.stat-card h3 {
    font-size: 26px;
    margin: 0;
    font-weight: 800;
}

.stat-card p {
    margin: 3px 0 0;
    color: var(--text-muted);
}

.panel-card {
    padding: 22px;
}

.table thead th {
    color: #475467;
    font-size: 13px;
    background: #f9fafb;
}

.login-page {
    min-height: 100vh;
    display: grid;
    place-items: center;
    padding: 24px;
    background: linear-gradient(135deg, #e0ecff, #f7fafc);
}

.login-card {
    width: 100%;
    max-width: 430px;
    background: #fff;
    border: 1px solid var(--card-border);
    border-radius: 24px;
    padding: 30px;
    box-shadow: 0 20px 50px rgba(15, 23, 42, .08);
}

@media (max-width: 991px) {
    .app-shell { padding-left: 0; }
    .app-sidebar { transform: translateX(-100%); }
    .app-sidebar.show { transform: translateX(0); }
    .app-topbar { padding: 14px 16px; align-items: flex-start; }
    .app-main { padding: 18px; }
}