body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    margin: 0;
    padding: 20px;
    background-color: #f0f2f5;
    color: #333;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    background-color: #fff;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 0 20px rgba(0,0,0,0.1);
    transition: all 0.3s ease;
}

h1, h2 {
    text-align: center;
    color: #2c3e50;
    margin-bottom: 20px;
}

h1 {
    font-size: 2.5em;
    margin-bottom: 30px;
}

form {
    display: flex;
    flex-direction: column;
    gap: 15px;
    margin-bottom: 30px;
    transition: all 0.3s ease;
}

input, select, .btn {
    padding: 12px;
    font-size: 16px;
    border: 1px solid #ddd;
    border-radius: 5px;
    transition: all 0.3s ease;
}

input:focus, select:focus {
    outline: none;
    border-color: #3498db;
    box-shadow: 0 0 5px rgba(52, 152, 219, 0.5);
}

.btn {
    background-color: #3498db;
    color: white;
    border: none;
    cursor: pointer;
    transition: all 0.3s ease;
}

.btn:hover {
    background-color: #2980b9;
    transform: translateY(-2px);
    box-shadow: 0 2px 5px rgba(0,0,0,0.2);
}

.btn-primary {
    background-color: #3498db;
}

.btn-success {
    background-color: #2ecc71;
}

.btn-warning {
    background-color: #f39c12;
}

.btn-danger {
    background-color: #e74c3c;
}

.task-list {
    list-style-type: none;
    padding: 0;
}

.task-item {
    background-color: #f9f9f9;
    margin-bottom: 10px;
    padding: 15px;
    border-radius: 5px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: all 0.3s ease;
    animation: fadeIn 0.5s ease;
}

.task-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.task-buttons {
    display: flex;
    gap: 10px;
}

.task-buttons button {
    padding: 8px 12px;
    font-size: 14px;
    border-radius: 3px;
}

.completed-list .task-item {
    background-color: #e8f6f3;
    color: #27ae60;
}

.hidden {
    display: none;
}

#toggle-form {
    margin-bottom: 20px;
    width: 100%;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

@media (max-width: 480px) {
    body {
        padding: 10px;
    }
    .container {
        padding: 20px;
    }
    .task-item {
        flex-direction: column;
        align-items: flex-start;
    }
    .task-buttons {
        margin-top: 10px;
    }
}