:root {
    --primary-color: #14e87a;
    --secondary-color: #6c757d;
    --success-color: #28a745;
    --danger-color: #dc3545;
    --light-color: #f8f9fae1;
    --dark-color: #343a40;
    --border-radius: 8px;
    --box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: #f5f7ff;
    color: #333;
    line-height: 1.6;
}

.container {
    max-width: 800px;
    margin: 2rem auto;
    padding: 0 1rem;
}

.app-header {
    text-align: center;
    margin-bottom: 2rem;
    color: var(--dark-color);
}

.app-header h1 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.app-header p {
    color: var(--secondary-color);
    font-size: 1.1rem;
}

.app-container {
    background-color: white;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    padding: 2rem;
}

.input-section {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
}

.input-section input {
    flex: 1;
    min-width: 200px;
    padding: 0.75rem 1rem;
    border: 2px solid #e9ecef;
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
}

.input-section input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(74, 107, 255, 0.2);
}

.input-section button {
    padding: 0.75rem 1.5rem;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 1rem;
    font-weight: 500;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.input-section button:hover {
    background-color: #3a5bef;
    transform: translateY(-2px);
}

.filter-options {
    display: flex;
    gap: 0.5rem;
    margin-top: 1rem;
    width: 100%;
}

.filter-btn {
    padding: 0.5rem 1rem;
    background-color: transparent;
    border: 1px solid #e9ecef;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.9rem;
}

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

.filter-btn:hover:not(.active) {
    background-color: #f1f3f5;
}

.task-stats {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
    font-size: 0.9rem;
    color: var(--secondary-color);
}

#clearCompleted {
    background: none;
    border: none;
    color: var(--secondary-color);
    cursor: pointer;
    font-size: 0.9rem;
    transition: var(--transition);
}

#clearCompleted:hover {
    color: var(--danger-color);
    text-decoration: underline;
}

#taskList {
    list-style: none;
}

.task-item {
    display: flex;
    align-items: center;
    padding: 1rem;
    background-color: white;
    border-radius: var(--border-radius);
    margin-bottom: 0.5rem;
    transition: var(--transition);
    border: 1px solid #e9ecef;
}

.task-item:hover {
    transform: translateY(-2px);
    box-shadow: var(--box-shadow);
}

.task-checkbox {
    margin-right: 1rem;
    width: 1.2rem;
    height: 1.2rem;
    cursor: pointer;
}

.task-text {
    flex: 1;
    word-break: break-word;
}

.task-text.completed {
    text-decoration: line-through;
    color: var(--secondary-color);
}

.task-actions {
    display: flex;
    gap: 0.5rem;
    margin-left: 1rem;
}

.task-actions button {
    background: none;
    border: none;
    cursor: pointer;
    color: var(--secondary-color);
    transition: var(--transition);
    width: 2rem;
    height: 2rem;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.task-actions button:hover {
    background-color: #f1f3f5;
    color: var(--danger-color);
}

.empty-state {
    text-align: center;
    padding: 2rem;
    color: var(--secondary-color);
}

.empty-state i {
    font-size: 3rem;
    margin-bottom: 1rem;
    color: #e9ecef;
}

@media (max-width: 600px) {
    .app-container {
        padding: 1rem;
    }
    
    .input-section {
        flex-direction: column;
    }
    
    .input-section button {
        justify-content: center;
    }
}