:root {
    --primary-color: #3498db;
    --secondary-color: #2c3e50;
    --accent-color: #e74c3c;
    --light-bg: #ecf0f1;
    --text-color: #333;
    --sidebar-text-color: #ecf0f1;
}

body {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    background-color: var(--light-bg);
    color: var(--text-color);
}

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

.navbar-brand, .navbar-nav .nav-link {
    color: white !important;
}

.sidebar {
    background-color: var(--secondary-color);
    min-height: calc(100vh - 56px - 40px);
    padding-top: 20px;
}

.sidebar .nav-link {
    color: var(--sidebar-text-color);
    padding: 0.5rem 1rem;
}

.sidebar .nav-link:hover {
    background-color: rgba(255,255,255,0.1);
}

.sidebar .nav-link.active {
    background-color: rgba(255,255,255,0.2);
    font-weight: bold;
}

.sidebar .submenu {
    padding-left: 1rem;
    list-style-type: none;
    display: none;
}

.sidebar .nav-item.open .submenu {
    display: block;
}

.sidebar .nav-link .fa-chevron-down {
    float: right;
    transition: transform 0.3s;
}

.sidebar .nav-item.open .nav-link .fa-chevron-down {
    transform: rotate(180deg);
}

.main-content {
    flex: 1;
    padding: 20px;
}

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

.btn-danger {
    background-color: var(--accent-color);
    border-color: var(--accent-color);
}

footer {
    background-color: var(--secondary-color);
    color: var(--sidebar-text-color);
    padding: 10px 0;
    text-align: center;
}