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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
    line-height: 1.6;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    background: white;
    border-radius: 16px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    padding: 40px;
}

header {
    text-align: center;
    margin-bottom: 40px;
}

header h1 {
    color: #333;
    font-size: 2.5rem;
    margin-bottom: 8px;
}

.subtitle {
    color: #666;
    font-size: 1.1rem;
}

.task-form {
    background: #f8f9fa;
    padding: 24px;
    border-radius: 12px;
    margin-bottom: 32px;
}

.task-form h2 {
    color: #333;
    font-size: 1.5rem;
    margin-bottom: 20px;
}

.form-group {
    margin-bottom: 16px;
}

.form-group label {
    display: block;
    color: #555;
    font-weight: 500;
    margin-bottom: 8px;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 12px;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    font-size: 1rem;
    font-family: inherit;
    transition: border-color 0.3s;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: #667eea;
}

.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
}

.btn-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 16px rgba(102, 126, 234, 0.4);
}

.filters {
    display: flex;
    gap: 12px;
    margin-bottom: 24px;
    justify-content: center;
}

.filter-btn {
    padding: 8px 20px;
    border: 2px solid #e0e0e0;
    background: white;
    border-radius: 20px;
    cursor: pointer;
    font-size: 0.9rem;
    font-weight: 500;
    color: #666;
    transition: all 0.3s;
}

.filter-btn:hover {
    border-color: #667eea;
    color: #667eea;
}

.filter-btn.active {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border-color: transparent;
}

.task-stats {
    text-align: center;
    color: #666;
    font-weight: 500;
    margin-bottom: 24px;
}

.task-list {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.task-item {
    background: white;
    border: 2px solid #e0e0e0;
    border-radius: 12px;
    padding: 20px;
    transition: all 0.3s;
}

.task-item:hover {
    border-color: #667eea;
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.15);
}

.task-item.completed {
    opacity: 0.6;
    background: #f8f9fa;
}

.task-header {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 8px;
}

.task-checkbox {
    width: 24px;
    height: 24px;
    cursor: pointer;
    accent-color: #667eea;
}

.task-title {
    flex: 1;
    font-size: 1.2rem;
    font-weight: 600;
    color: #333;
}

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

.task-description {
    color: #666;
    margin-left: 36px;
    margin-bottom: 12px;
}

.task-actions {
    display: flex;
    justify-content: flex-end;
    margin-left: 36px;
}

.btn-delete {
    background: #ff4757;
    color: white;
    padding: 8px 16px;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.9rem;
    font-weight: 500;
    transition: all 0.3s;
}

.btn-delete:hover {
    background: #ff3838;
    transform: translateY(-2px);
}

.empty-state {
    text-align: center;
    padding: 60px 20px;
    color: #999;
    font-size: 1.1rem;
}

.empty-state.hidden {
    display: none;
}

/* Notification */
.notification {
    position: fixed;
    top: 20px;
    right: 20px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 16px 24px;
    border-radius: 8px;
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.2);
    font-weight: 500;
    opacity: 0;
    transform: translateY(-20px);
    transition: all 0.3s ease;
    z-index: 1000;
}

.notification.show {
    opacity: 1;
    transform: translateY(0);
}

@media (max-width: 640px) {
    .container {
        padding: 24px;
    }

    header h1 {
        font-size: 2rem;
    }

    .filters {
        flex-wrap: wrap;
    }

    .notification {
        top: 10px;
        right: 10px;
        left: 10px;
        text-align: center;
    }
}