* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Arial', sans-serif;
}

body {
    background: linear-gradient(135deg, #7f7fd5, #86a8e7, #91eae4);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

.container {
    width: 100%;
    max-width: 600px;
}

h1 {
    color: white;
    text-align: center;
    margin-bottom: 20px;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.2);
}

.todo-app {
    background-color: white;
    border-radius: 10px;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
    padding: 20px;
}

.input-section {
    display: flex;
    margin-bottom: 20px;
}

#task-input {
    flex-grow: 1;
    padding: 12px;
    border: 1px solid #ddd;
    border-radius: 4px 0 0 4px;
    font-size: 16px;
}

#add-button {
    border: none;
    background-color: #4a90e2;
    color: white;
    padding: 12px 15px;
    cursor: pointer;
    border-radius: 0 4px 4px 0;
    font-size: 16px;
    transition: background-color 0.3s;
}

#add-button:hover {
    background-color: #357abd;
}

.filters {
    display: flex;
    justify-content: center;
    margin-bottom: 20px;
    gap: 10px;
}

.filter {
    border: none;
    background-color: transparent;
    padding: 8px 12px;
    cursor: pointer;
    font-size: 14px;
    border-radius: 4px;
    transition: background-color 0.3s;
}

.filter:hover {
    background-color: #f0f0f0;
}

.filter.active {
    background-color: #4a90e2;
    color: white;
}

#task-list {
    list-style-type: none;
    margin-bottom: 20px;
}

.task-item {
    display: flex;
    align-items: center;
    padding: 12px 0;
    border-bottom: 1px solid #eee;
}

.task-item.completed .task-text {
    text-decoration: line-through;
    color: #aaa;
}

.task-check {
    margin-right: 10px;
    cursor: pointer;
    font-size: 18px;
    color: #ddd;
}

.task-item.completed .task-check {
    color: #4a90e2;
}

.task-text {
    flex-grow: 1;
    font-size: 16px;
}

.delete-task {
    border: none;
    background-color: transparent;
    color: #ff6b6b;
    cursor: pointer;
    font-size: 18px;
    transition: color 0.3s;
}

.delete-task:hover {
    color: #ff4f4f;
}

.clear-section {
    display: flex;
    justify-content: space-between;
    color: #777;
    font-size: 14px;
}

#clear-completed {
    border: none;
    background-color: transparent;
    color: #4a90e2;
    cursor: pointer;
    font-size: 14px;
    transition: color 0.3s;
}

#clear-completed:hover {
    color: #357abd;
}

footer {
    margin-top: 20px;
    text-align: center;
    color: white;
    font-size: 14px;
}

footer a {
    color: #fff;
    text-decoration: none;
    font-weight: bold;
}

footer a:hover {
    text-decoration: underline;
}

@media (max-width: 768px) {
    .container {
        padding: 10px;
    }
    
    #task-input, #add-button {
        font-size: 14px;
        padding: 10px;
    }
    
    .filter {
        font-size: 12px;
        padding: 6px 10px;
    }
}