body {
    background-color: #f8f9fa;
    color: #212529;
    font-family: Arial, sans-serif;
}

.container {
    max-width: 800px;
    margin: 20px auto;
    padding: 20px;
    background-color: #fff;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    border-radius: 10px;
}

.list-group-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    opacity: 0;
    transform: translateY(-10px);
    transition: opacity 0.5s ease, transform 0.5s ease;
}

.list-group-item.appear {
    opacity: 1;
    transform: translateY(0);
}

.dark-mode {
    background-color: #333;
    color: #fff;
}

.dark-mode .container {
    background-color: #444;
}

.dark-mode .form-control {
    background-color: #555;
    color: #fff;
}

.dark-mode .btn {
    background-color: #666;
}

.alert {
    display: none;
    padding: 15px;
    margin-top: 10px;
    border-radius: 5px;
    text-align: center;
}

.alert-success {
    background-color: #d4edda;
    color: #155724;
}

.alert-error {
    background-color: #f8d7da;
    color: #721c24;
}