body {
    background-color: #f4f7f6;
    font-family: 'Noto Sans Bengali', sans-serif;
}
.sidebar {
    position: fixed;
    top: 0;
    left: 0;
    height: 100%;
    width: 250px;
    background-color: #212529; /* Darker sidebar */
    color: white;
    padding-top: 20px;
    transition: all 0.3s;
}
.sidebar .sidebar-header {
    text-align: center;
    margin-bottom: 30px;
    font-size: 24px;
    color: #fff;
}
.sidebar .nav-link {
    color: #adb5bd;
    font-size: 16px;
    padding: 12px 20px;
    display: block;
    text-decoration: none;
    transition: all 0.3s;
    border-left: 3px solid transparent;
}
.sidebar .nav-link:hover, .sidebar .nav-link.active {
    color: white;
    background-color: #343a40;
    border-left: 3px solid #0d6efd;
}
.sidebar .nav-link i.nav-icon {
    margin-right: 15px;
    width: 20px;
    text-align: center;
}
.main-content {
    margin-left: 250px;
    padding: 20px;
}
.main-content .navbar {
    background-color: white;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}
.stat-card {
    border-radius: 8px;
    padding: 20px;
    color: white;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}