* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: #f5f7fa;
    color: #333;
}

.dashboard-container {
    display: grid;
    grid-template-columns: 240px 1fr;
    grid-template-rows: 60px 1fr;
    grid-template-areas: 
        "sidebar header"
        "sidebar main";
    height: 100vh;
}

.sidebar {
    grid-area: sidebar;
    background-color: #2c3e50;
    color: #ecf0f1;
    padding: 20px 0;
    box-shadow: 2px 0 5px rgba(0,0,0,0.1);
}

.logo {
    display: flex;
    align-items: center;
    padding: 0 20px 20px 20px;
    border-bottom: 1px solid rgba(255,255,255,0.1);
    margin-bottom: 20px;
}

.nav-menu {
    list-style: none;
}

.nav-item {
    padding: 12px 20px;
    display: flex;
    align-items: center;
    cursor: pointer;
    transition: background-color 0.2s;
}

.nav-item.active {
    background-color: rgba(52, 152, 219, 0.2);
    border-left: 4px solid #3498db;
}

.header {
    grid-area: header;
    background-color: white;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 30px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    z-index: 10;
}

.main-content {
    grid-area: main;
    padding: 20px;
    overflow-y: auto;
}

.stat-card {
    background-color: white;
    border-radius: 8px;
    padding: 20px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}