/* Modern Todo Manager Styles */
:root {
    --primary-color: #3b82f6;
    --secondary-color: #64748b;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --danger-color: #ef4444;
    --background-color: #f8fafc;
    --surface-color: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --shadow: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --border-radius: 8px;
    --transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background-color: var(--background-color);
    color: var(--text-primary);
    line-height: 1.6;
}

.app-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 20px;
}

/* Header Styles */
.app-header {
    background: var(--surface-color);
    padding: 24px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    margin-bottom: 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 16px;
}

.app-header h1 {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 12px;
}

.app-header h1 i {
    color: var(--primary-color);
}

.header-controls {
    display: flex;
    align-items: center;
    gap: 16px;
    flex-wrap: wrap;
}

.filter-controls {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

/* Button Styles */
.btn {
    padding: 10px 20px;
    border: none;
    border-radius: var(--border-radius);
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 8px;
    text-decoration: none;
    font-size: 14px;
}

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

.btn-primary:hover {
    background: #2563eb;
    transform: translateY(-1px);
}

.btn-secondary {
    background: var(--secondary-color);
    color: white;
}

.btn-secondary:hover {
    background: #475569;
}

.btn-danger {
    background: var(--danger-color);
    color: white;
}

.btn-danger:hover {
    background: #dc2626;
}

/* Select Styles */
select {
    padding: 8px 12px;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    background: var(--surface-color);
    color: var(--text-primary);
    font-size: 14px;
    cursor: pointer;
    transition: var(--transition);
}

select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgb(59 130 246 / 0.1);
}

/* Stats Bar */
.stats-bar {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 16px;
    margin-bottom: 24px;
}

.stat-card {
    background: var(--surface-color);
    padding: 20px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    text-align: center;
    transition: var(--transition);
}

.stat-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.stat-number {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 4px;
}

.stat-label {
    color: var(--text-secondary);
    font-size: 14px;
    font-weight: 500;
}

/* Todo Groups */
.todo-groups {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 24px;
}

.todo-group {
    background: var(--surface-color);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    overflow: hidden;
}

.group-title {
    padding: 16px 20px;
    font-size: 1.1rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 8px;
    border-bottom: 2px solid var(--border-color);
}

.group-title.high-priority {
    background: #fafafa;
    color: #ef4444;
    border-left: 3px solid #ef4444;
}

.group-title.medium-priority {
    background: #fafafa;
    color: #f59e0b;
    border-left: 3px solid #f59e0b;
}

.group-title.low-priority {
    background: #fafafa;
    color: #10b981;
    border-left: 3px solid #10b981;
}

.todo-list {
    min-height: 120px;
    padding: 8px;
}

/* Todo Item Styles - Minimal Design */
.todo-item {
    background: #ffffff;
    border: 1px solid #e5e7eb;
    border-radius: 4px;
    padding: 8px 12px;
    margin-bottom: 6px;
    transition: var(--transition);
    cursor: grab;
    font-size: 14px;
    line-height: 1.4;
}

.todo-item:hover {
    border-color: #d1d5db;
    background: #fafafa;
}

.todo-item.completed {
    opacity: 0.6;
    background: #f9f9f9;
}

.todo-item.completed .todo-title {
    text-decoration: line-through;
    color: #9ca3af;
}

.todo-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 8px;
}

.todo-title {
    font-weight: 400;
    font-size: 14px;
    color: #374151;
    flex: 1;
    line-height: 1.3;
}

.todo-actions {
    display: flex;
    gap: 4px;
    opacity: 0;
    transition: opacity 0.2s;
}

.todo-item:hover .todo-actions {
    opacity: 1;
}

.todo-actions button {
    background: none;
    border: none;
    padding: 2px 4px;
    border-radius: 2px;
    cursor: pointer;
    font-size: 12px;
    color: #9ca3af;
    min-width: 16px;
    height: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.todo-actions button:hover {
    background: #f3f4f6;
    color: #6b7280;
}

.todo-due {
    font-size: 11px;
    color: #dc2626;
    margin-top: 4px;
    font-weight: 500;
}

/* Minimal Priority Indicators */
.todo-item[data-priority="high"] {
    border-left: 2px solid #ef4444;
}

.todo-item[data-priority="medium"] {
    border-left: 2px solid #f59e0b;
}

.todo-item[data-priority="low"] {
    border-left: 2px solid #10b981;
}

/* 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(4px);
}

.modal.active {
    display: flex;
    align-items: center;
    justify-content: center;
    animation: fadeIn 0.2s ease-out;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.modal-content {
    background: var(--surface-color);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-lg);
    width: 90%;
    max-width: 500px;
    max-height: 90vh;
    overflow-y: auto;
    animation: slideIn 0.3s ease-out;
}

@keyframes slideIn {
    from {
        transform: translateY(-20px);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

.modal-header {
    padding: 20px 24px;
    border-bottom: 2px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-header h2 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
}

.close-btn {
    background: none;
    border: none;
    font-size: 24px;
    cursor: pointer;
    color: var(--text-secondary);
    padding: 0;
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 4px;
    transition: var(--transition);
}

.close-btn:hover {
    background: var(--border-color);
    color: var(--text-primary);
}

/* Form Styles */
#todo-form {
    padding: 24px;
}

.form-group {
    margin-bottom: 20px;
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

.form-group label {
    display: block;
    margin-bottom: 6px;
    font-weight: 500;
    color: var(--text-primary);
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 10px 12px;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 14px;
    transition: var(--transition);
    background: var(--surface-color);
    color: var(--text-primary);
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgb(59 130 246 / 0.1);
}

.form-group textarea {
    resize: vertical;
    font-family: inherit;
}

.modal-actions {
    display: flex;
    justify-content: flex-end;
    gap: 12px;
    margin-top: 24px;
}

/* Responsive Design */
@media (max-width: 768px) {
    .app-container {
        padding: 12px;
    }
    
    .app-header {
        flex-direction: column;
        align-items: stretch;
        text-align: center;
    }
    
    .header-controls {
        justify-content: center;
    }
    
    .filter-controls {
        justify-content: center;
    }
    
    .todo-groups {
        grid-template-columns: 1fr;
    }
    
    .stats-bar {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .modal-content {
        width: 95%;
        margin: 20px;
    }
}

/* Drag and Drop Styles */
.todo-item.dragging {
    opacity: 0.4;
    transform: rotate(1deg);
    cursor: grabbing;
}

.todo-list.drag-over {
    background: rgba(59, 130, 246, 0.05);
    border: 1px dashed #93c5fd;
    border-radius: 4px;
}

/* Animation for new todos */
.todo-item.new-item {
    animation: slideInUp 0.3s ease-out;
}

@keyframes slideInUp {
    from {
        transform: translateY(20px);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

/* Empty state */
.empty-state {
    text-align: center;
    padding: 40px 20px;
    color: var(--text-secondary);
}

.empty-state i {
    font-size: 3rem;
    margin-bottom: 16px;
    opacity: 0.5;
}

.empty-state h3 {
    margin-bottom: 8px;
    font-weight: 600;
}

.empty-state p {
    font-size: 14px;
}