* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.container {
    background: white;
    border-radius: 15px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    max-width: 600px;
    width: 100%;
    padding: 30px;
    margin-top: 50px;
}

header {
    text-align: center;
    margin-bottom: 30px;
}

header h1 {
    color: #667eea;
    font-size: 2.5em;
    margin-bottom: 10px;
}

.subtitle {
    color: #666;
    font-size: 0.9em;
}

.task-input-section {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
}

#taskInput {
    flex: 1;
    padding: 12px 15px;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    font-size: 16px;
    transition: border-color 0.3s;
}

#taskInput:focus {
    outline: none;
    border-color: #667eea;
}

button {
    padding: 12px 24px;
    background: #667eea;
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 16px;
    transition: background 0.3s;
}

button:hover {
    background: #5568d3;
}

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

.filter-btn {
    padding: 8px 16px;
    background: #f0f0f0;
    color: #333;
    font-size: 14px;
}

.filter-btn.active {
    background: #667eea;
    color: white;
}

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

.task-item {
    display: flex;
    align-items: center;
    padding: 15px;
    background: #f9f9f9;
    margin-bottom: 10px;
    border-radius: 8px;
    transition: all 0.3s;
}

.task-item:hover {
    background: #f0f0f0;
    transform: translateX(5px);
}

.task-item.completed {
    opacity: 0.6;
}

.task-item.completed .task-text {
    text-decoration: line-through;
    color: #999;
}

.task-checkbox {
    width: 20px;
    height: 20px;
    margin-right: 15px;
    cursor: pointer;
}

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

.delete-btn {
    background: #ff6b6b;
    padding: 6px 12px;
    font-size: 14px;
}

.delete-btn:hover {
    background: #ff5252;
}

.stats {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 20px;
    border-top: 2px solid #e0e0e0;
    font-size: 14px;
    color: #666;
}

#clearCompleted {
    background: #ff6b6b;
    padding: 8px 16px;
    font-size: 14px;
}

footer {
    margin-top: 30px;
    text-align: center;
    color: white;
    font-size: 14px;
}

@media (max-width: 600px) {
    .container {
        padding: 20px;
    }
    
    header h1 {
        font-size: 2em;
    }
    
    .task-input-section {
        flex-direction: column;
    }
}