body {
    margin: 0;
    font-family: Arial, sans-serif;
}

.sidebar {
    width: 250px;
    height: 100vh;
    background: #1f2937;
    color: #fff;
    position: fixed;
}

.menu {
    list-style: none;
    padding: 0;
    margin: 0;
}

.menu-item {
    border-bottom: 1px solid #374151;
}

.menu-link {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px 15px;
    color: #e5e7eb;
    text-decoration: none;
    cursor: pointer;
}

.menu-link i {
    margin-right: 10px;
}

.menu-link:hover {
    background: #374151;
}

.submenu {
    display: none;
    list-style: none;
    padding-left: 20px;
    background: #111827;
}

.submenu li a {
    display: block;
    padding: 10px;
    color: #cbd5f5;
    text-decoration: none;
}

.submenu li a:hover {
    background: #1f2937;
}

.menu-item.active .submenu {
    display: block;
}

.arrow {
    transition: transform 0.3s ease;
}

.menu-item.active .arrow {
    transform: rotate(180deg);
}