* {
    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;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    background: white;
    border-radius: 15px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
    overflow: hidden;
}

/* Header Styles */
header {
    background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    color: white;
    padding: 30px;
    text-align: center;
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 15px;
    font-weight: 600;
}

.stats {
    display: flex;
    justify-content: center;
    gap: 20px;
    font-size: 0.9rem;
    opacity: 0.9;
}

.stats span {
    background: rgba(255, 255, 255, 0.2);
    padding: 5px 12px;
    border-radius: 20px;
    backdrop-filter: blur(10px);
}

/* Input Section */
.input-section {
    padding: 30px;
    background: #f8f9fa;
    border-bottom: 1px solid #e9ecef;
}

.input-container {
    display: flex;
    gap: 10px;
    align-items: center;
    flex-wrap: wrap;
}

#todo-input {
    flex: 1;
    min-width: 200px;
    padding: 12px 16px;
    border: 2px solid #e9ecef;
    border-radius: 8px;
    font-size: 1rem;
    transition: all 0.3s ease;
}

#todo-input:focus {
    outline: none;
    border-color: #4facfe;
    box-shadow: 0 0 0 3px rgba(79, 172, 254, 0.1);
}

#priority-select {
    padding: 12px 16px;
    border: 2px solid #e9ecef;
    border-radius: 8px;
    font-size: 1rem;
    background: white;
    cursor: pointer;
}

.btn {
    padding: 12px 20px;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    gap: 8px;
}

.btn-primary {
    background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(79, 172, 254, 0.4);
}

.btn-danger {
    background: linear-gradient(135deg, #ff6b6b 0%, #ee5a24 100%);
    color: white;
}

.btn-danger:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(255, 107, 107, 0.4);
}

.btn-warning {
    background: linear-gradient(135deg, #feca57 0%, #ff9ff3 100%);
    color: white;
}

.btn-warning:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(254, 202, 87, 0.4);
}

.btn-secondary {
    background: #6c757d;
    color: white;
}

.btn-secondary:hover {
    background: #5a6268;
}

/* Filter Section */
.filter-section {
    padding: 20px 30px;
    background: white;
    border-bottom: 1px solid #e9ecef;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 15px;
}

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

.filter-btn {
    padding: 8px 16px;
    border: 2px solid #e9ecef;
    background: white;
    border-radius: 20px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: all 0.3s ease;
}

.filter-btn.active,
.filter-btn:hover {
    background: #4facfe;
    color: white;
    border-color: #4facfe;
}

#sort-select {
    padding: 8px 12px;
    border: 2px solid #e9ecef;
    border-radius: 6px;
    background: white;
    cursor: pointer;
}

/* Todo List */
.todo-list-container {
    min-height: 300px;
    max-height: 500px;
    overflow-y: auto;
}

.todo-list {
    list-style: none;
    padding: 0;
}

.todo-item {
    display: flex;
    align-items: center;
    padding: 20px 30px;
    border-bottom: 1px solid #f1f3f4;
    transition: all 0.3s ease;
    animation: slideIn 0.3s ease;
}

.todo-item:hover {
    background: #f8f9fa;
}

.todo-item.completed {
    opacity: 0.7;
    background: #f8f9fa;
}

.todo-checkbox {
    width: 20px;
    height: 20px;
    margin-right: 15px;
    cursor: pointer;
    accent-color: #4facfe;
}

.todo-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    margin-right: 15px;
}

.todo-text {
    font-size: 1.1rem;
    margin-bottom: 5px;
    transition: all 0.3s ease;
}

.todo-item.completed .todo-text {
    text-decoration: line-through;
    color: #6c757d;
}

.todo-meta {
    display: flex;
    gap: 10px;
    align-items: center;
    font-size: 0.8rem;
    color: #6c757d;
}

.priority-badge {
    padding: 2px 8px;
    border-radius: 10px;
    font-size: 0.7rem;
    font-weight: 500;
    text-transform: uppercase;
}

.priority-high {
    background: #ff6b6b;
    color: white;
}

.priority-medium {
    background: #feca57;
    color: white;
}

.priority-low {
    background: #48cab2;
    color: white;
}

.todo-actions {
    display: flex;
    gap: 10px;
}

.action-btn {
    padding: 8px;
    border: none;
    background: none;
    cursor: pointer;
    border-radius: 4px;
    transition: all 0.3s ease;
    color: #6c757d;
}

.action-btn:hover {
    background: #e9ecef;
    color: #495057;
}

.edit-btn:hover {
    color: #4facfe;
}

.delete-btn:hover {
    color: #ff6b6b;
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: 60px 30px;
    color: #6c757d;
}

.empty-state i {
    font-size: 4rem;
    margin-bottom: 20px;
    opacity: 0.5;
}

.empty-state p {
    font-size: 1.2rem;
}

/* Actions Section */
.actions-section {
    padding: 20px 30px;
    background: #f8f9fa;
    display: flex;
    justify-content: center;
    gap: 15px;
}

/* Modal Styles */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(5px);
}

.modal-content {
    background-color: white;
    margin: 10% auto;
    padding: 0;
    border-radius: 15px;
    width: 90%;
    max-width: 500px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.2);
    animation: modalSlideIn 0.3s ease;
}

.modal-header {
    padding: 20px 30px;
    background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    color: white;
    border-radius: 15px 15px 0 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-header h3 {
    margin: 0;
    font-size: 1.3rem;
}

.close {
    font-size: 1.5rem;
    cursor: pointer;
    line-height: 1;
}

.close:hover {
    opacity: 0.7;
}

.modal-body {
    padding: 30px;
}

.modal-body input,
.modal-body select {
    width: 100%;
    padding: 12px;
    margin-bottom: 15px;
    border: 2px solid #e9ecef;
    border-radius: 8px;
    font-size: 1rem;
}

.modal-body input:focus {
    outline: none;
    border-color: #4facfe;
}

.modal-footer {
    padding: 20px 30px;
    display: flex;
    justify-content: flex-end;
    gap: 10px;
    background: #f8f9fa;
    border-radius: 0 0 15px 15px;
}

/* Animations */
@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateX(-20px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes modalSlideIn {
    from {
        opacity: 0;
        transform: translateY(-50px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        margin: 10px;
        border-radius: 10px;
    }
    
    header {
        padding: 20px;
    }
    
    header h1 {
        font-size: 2rem;
    }
    
    .stats {
        flex-direction: column;
        gap: 10px;
    }
    
    .input-section {
        padding: 20px;
    }
    
    .input-container {
        flex-direction: column;
        align-items: stretch;
    }
    
    .input-container > * {
        width: 100%;
    }
    
    .filter-section {
        padding: 15px 20px;
        flex-direction: column;
        align-items: stretch;
    }
    
    .filter-buttons {
        justify-content: center;
        margin-bottom: 15px;
    }
    
    .todo-item {
        padding: 15px 20px;
        flex-wrap: wrap;
    }
    
    .todo-content {
        margin-bottom: 10px;
    }
    
    .actions-section {
        padding: 15px 20px;
        flex-direction: column;
    }
    
    .modal-content {
        margin: 5% auto;
        width: 95%;
    }
}