:root {
    --primary: #2563eb;
    --secondary: #475569;
    --bg-light: #f8fafc;
    --white: #ffffff;
    --border: #e2e8f0;
    --text-dark: #1e293b;
}

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-light);
    color: var(--text-dark);
    margin: 0;
    display: flex;
    height: 100vh;
}

/* Sidebar */
.sidebar {
    width: 250px;
    background: var(--white);
    border-right: 1px solid var(--border);
    padding: 20px;
    display: flex;
    flex-direction: column;
}

.sidebar h2 {
    color: var(--primary);
    font-size: 1.5rem;
    margin-bottom: 2rem;
}

.nav-link {
    text-decoration: none;
    color: var(--secondary);
    padding: 12px;
    border-radius: 8px;
    margin-bottom: 5px;
    transition: 0.2s;
}

.nav-link:hover, .nav-link.active {
    background-color: #eff6ff;
    color: var(--primary);
    font-weight: 600;
}

/* Main Content */
.main-content {
    flex: 1;
    padding: 30px;
    overflow-y: auto;
}

.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
}

.btn {
    padding: 10px 20px;
    border-radius: 6px;
    border: none;
    cursor: pointer;
    font-weight: 500;
    text-decoration: none;
    display: inline-block;
}

.btn-primary {
    background-color: var(--primary);
    color: white;
}

/* Cards */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.card {
    background: var(--white);
    padding: 20px;
    border-radius: 12px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
    border: 1px solid var(--border);
}

.stat-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-dark);
}

.stat-label {
    color: var(--secondary);
    font-size: 0.9rem;
}

/* Tables */
.table-container {
    background: var(--white);
    border-radius: 12px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
    overflow: hidden;
}

table {
    width: 100%;
    border-collapse: collapse;
}

th, td {
    padding: 15px;
    text-align: left;
    border-bottom: 1px solid var(--border);
}

th {
    background-color: #f1f5f9;
    font-weight: 600;
    color: var(--secondary);
}