:root {
    --primary: #2563eb;
    --primary-light: #60a5fa;
    --secondary: #64748b;
    --bg-main: #f8fafc;
    --bg-card: rgba(255, 255, 255, 0.8);
    --sidebar-bg: #1e293b;
    --sidebar-hover: #334155;
    --text-main: #1e293b;
    --text-muted: #64748b;
    --border: #e2e8f0;
    --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --glass: blur(12px);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    background-color: var(--bg-main);
    color: var(--text-main);
}

.app-container {
    display: flex;
    min-height: 100vh;
}

/* Sidebar Styling */
.sidebar {
    width: 260px;
    background-color: var(--sidebar-bg);
    color: white;
    display: flex;
    flex-direction: column;
    transition: all 0.3s ease;
    z-index: 1000;
}

.sidebar-header {
    padding: 2rem 1.5rem;
    font-size: 1.25rem;
    font-weight: 700;
    letter-spacing: -0.025em;
    display: flex;
    align-items: center;
    gap: 0.75rem;
    border-bottom: 1px solid var(--sidebar-hover);
}

.nav-menu {
    flex: 1;
    padding: 1.5rem 0.75rem;
}

.nav-item {
    display: flex;
    align-items: center;
    padding: 0.75rem 1rem;
    margin-bottom: 0.5rem;
    border-radius: 0.5rem;
    color: #cbd5e1;
    text-decoration: none;
    transition: all 0.2s;
    font-size: 0.95rem;
}

.nav-item:hover, .nav-item.active {
    background-color: var(--sidebar-hover);
    color: white;
}

.nav-item i {
    width: 20px;
}

/* Main Content Area */
.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow-x: hidden;
}

.top-navbar {
    height: 64px;
    background-color: var(--bg-card);
    backdrop-filter: var(--glass);
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 2rem;
    position: sticky;
    top: 0;
    z-index: 900;
}

.page-container {
    padding: 2rem;
    max-width: 1400px;
    margin: 0 auto;
    width: 100%;
}

/* Card Styling */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.card {
    background: var(--bg-card);
    backdrop-filter: var(--glass);
    border: 1px solid var(--border);
    border-radius: 1rem;
    padding: 1.5rem;
    box-shadow: var(--shadow);
    transition: transform 0.2s;
}

.card:hover {
    transform: translateY(-2px);
}

.kpi-title {
    font-size: 0.875rem;
    color: var(--text-muted);
    font-weight: 500;
    margin-bottom: 0.5rem;
}

.kpi-value {
    font-size: 1.875rem;
    font-weight: 700;
    color: var(--text-main);
}

/* Charts Grid */
.charts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(450px, 1fr));
    gap: 1.5rem;
}

@media (max-width: 768px) {
    .sidebar { width: 0; overflow: hidden; }
    .charts-grid { grid-template-columns: 1fr; }
}