/* Reset & Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #3498db;
    --secondary-color: #2ecc71;
    --danger-color: #e74c3c;
    --warning-color: #f39c12;
    --dark-color: #2c3e50;
    --light-color: #ecf0f1;
    --gray-color: #7f8c8d;
    --light-gray: #f8f9fa;
    --border-radius: 12px;
    --box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
    
    /* Light theme */
    --bg-color: #f5f7fa;
    --card-bg: #ffffff;
    --text-color: #333333;
    --border-color: #e1e5e9;
}

.dark-theme {
    --bg-color: #1a1a2e;
    --card-bg: #16213e;
    --text-color: #e6e6e6;
    --border-color: #2d3748;
}

body {
    font-family: 'Inter', sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
    transition: var(--transition);
    min-height: 100vh;
}

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

/* Header */
.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 0;
    margin-bottom: 30px;
    border-bottom: 2px solid var(--border-color);
}

.logo {
    display: flex;
    align-items: center;
    gap: 15px;
}

.logo i {
    font-size: 2.5rem;
    color: var(--primary-color);
}

.logo h1 {
    font-size: 2rem;
    font-weight: 700;
    background: linear-gradient(45deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.tagline {
    color: var(--gray-color);
    font-size: 0.9rem;
    margin-left: 10px;
    font-style: italic;
}

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

/* Buttons */
.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-family: 'Inter', sans-serif;
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color), #2980b9);
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(52, 152, 219, 0.3);
}

.btn-secondary {
    background-color: var(--card-bg);
    color: var(--text-color);
    border: 2px solid var(--border-color);
}

.btn-secondary:hover {
    background-color: var(--border-color);
    transform: translateY(-2px);
}

.btn-danger {
    background: linear-gradient(135deg, var(--danger-color), #c0392b);
    color: white;
}

.btn-danger:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(231, 76, 60, 0.3);
}

.btn-danger:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.btn-icon {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    border: none;
    background: var(--card-bg);
    color: var(--text-color);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
    font-size: 1.1rem;
}

.btn-icon:hover {
    background-color: var(--primary-color);
    color: white;
    transform: rotate(10deg);
}

/* Main Content Layout */
.main-content {
    display: grid;
    grid-template-columns: 350px 1fr;
    gap: 30px;
    margin-bottom: 40px;
}

/* Cards */
.card {
    background: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 25px;
    box-shadow: var(--box-shadow);
    margin-bottom: 25px;
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.15);
}

.card h2 {
    font-size: 1.3rem;
    margin-bottom: 20px;
    color: var(--text-color);
    display: flex;
    align-items: center;
    gap: 10px;
}

.card h2 i {
    color: var(--primary-color);
}

/* Add Task Form */
.add-task-form {
    margin-bottom: 25px;
}

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

.form-group label {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--text-color);
}

.form-group label i {
    color: var(--primary-color);
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 14px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-family: 'Inter', sans-serif;
    font-size: 1rem;
    background: var(--bg-color);
    color: var(--text-color);
    transition: var(--transition);
}

.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 rgba(52, 152, 219, 0.2);
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
}

/* Categories */
.category-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.category-btn {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 15px;
    border: none;
    background: var(--bg-color);
    color: var(--text-color);
    border-radius: 8px;
    cursor: pointer;
    transition: var(--transition);
    font-size: 1rem;
    text-align: left;
}

.category-btn i {
    margin-right: 10px;
    font-size: 1.1rem;
}

.category-btn:hover {
    background: var(--primary-color);
    color: white;
    transform: translateX(5px);
}

.category-btn.active {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    transform: translateX(5px);
}

.category-count {
    background: var(--card-bg);
    color: var(--text-color);
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
}

.category-btn.active .category-count {
    background: rgba(255, 255, 255, 0.2);
    color: white;
}

/* Quick Stats */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 15px;
}

.stat-item {
    text-align: center;
    padding: 15px;
    background: var(--bg-color);
    border-radius: 8px;
}

.stat-number {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 5px;
}

.stat-label {
    font-size: 0.9rem;
    color: var(--gray-color);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

/* Task List Header */
.task-list-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 25px;
}

.task-list-header h2 {
    font-size: 1.8rem;
    color: var(--text-color);
}

.search-box {
    position: relative;
    width: 250px;
}

.search-box i {
    position: absolute;
    left: 15px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--gray-color);
}

.search-box input {
    width: 100%;
    padding: 12px 20px 12px 45px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    background: var(--card-bg);
    color: var(--text-color);
    font-family: 'Inter', sans-serif;
    transition: var(--transition);
}

.search-box input:focus {
    outline: none;
    border-color: var(--primary-color);
}

/* Task Filters */
.task-filters {
    background: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 20px;
    margin-bottom: 25px;
    box-shadow: var(--box-shadow);
}

.filter-buttons {
    display: flex;
    gap: 10px;
    margin-bottom: 15px;
    flex-wrap: wrap;
}

.filter-btn {
    padding: 10px 20px;
    border: 2px solid var(--border-color);
    background: var(--bg-color);
    color: var(--text-color);
    border-radius: 20px;
    cursor: pointer;
    font-weight: 500;
    transition: var(--transition);
}

.filter-btn:hover {
    background: var(--border-color);
}

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

.priority-filters {
    display: flex;
    align-items: center;
    gap: 10px;
    flex-wrap: wrap;
}

.filter-label {
    color: var(--gray-color);
    font-weight: 500;
}

.priority-filter-btn {
    padding: 8px 15px;
    border: 2px solid var(--border-color);
    background: var(--bg-color);
    color: var(--text-color);
    border-radius: 20px;
    cursor: pointer;
    font-size: 0.9rem;
    display: flex;
    align-items: center;
    gap: 5px;
    transition: var(--transition);
}

.priority-filter-btn:hover {
    background: var(--border-color);
}

.priority-filter-btn.active {
    color: white;
    border-color: transparent;
}

.priority-filter-btn[data-priority="high"].active {
    background: var(--danger-color);
}

.priority-filter-btn[data-priority="medium"].active {
    background: var(--warning-color);
}

.priority-filter-btn[data-priority="low"].active {
    background: var(--secondary-color);
}

/* Task List */
.task-list {
    min-height: 500px;
    background: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 25px;
    box-shadow: var(--box-shadow);
    margin-bottom: 25px;
}

.empty-state {
    text-align: center;
    padding: 60px 20px;
    color: var(--gray-color);
}

.empty-state i {
    font-size: 4rem;
    margin-bottom: 20px;
    opacity: 0.3;
}

.empty-state h3 {
    font-size: 1.5rem;
    margin-bottom: 10px;
    color: var(--text-color);
}

/* Task Item */
.task-item {
    background: var(--bg-color);
    border-radius: 10px;
    padding: 20px;
    margin-bottom: 15px;
    border-left: 5px solid var(--border-color);
    transition: var(--transition);
    position: relative;
    display: flex;
    align-items: flex-start;
    gap: 15px;
}

.task-item:hover {
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

.task-item.high-priority {
    border-left-color: var(--danger-color);
}

.task-item.medium-priority {
    border-left-color: var(--warning-color);
}

.task-item.low-priority {
    border-left-color: var(--secondary-color);
}

.task-item.overdue {
    background: linear-gradient(135deg, rgba(231, 76, 60, 0.1), var(--bg-color));
    border-left-color: var(--danger-color);
}

.task-item.completed {
    background: linear-gradient(135deg, rgba(46, 204, 113, 0.1), var(--bg-color));
    border-left-color: var(--secondary-color);
    opacity: 0.8;
}

.task-checkbox {
    position: relative;
}

.task-checkbox input[type="checkbox"] {
    display: none;
}

.checkmark {
    width: 24px;
    height: 24px;
    border: 2px solid var(--border-color);
    border-radius: 6px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition);
}

.checkmark:hover {
    border-color: var(--primary-color);
}

.checkmark i {
    color: white;
    font-size: 0.9rem;
    opacity: 0;
    transition: var(--transition);
}

.task-checkbox input[type="checkbox"]:checked ~ .checkmark {
    background: var(--secondary-color);
    border-color: var(--secondary-color);
}

.task-checkbox input[type="checkbox"]:checked ~ .checkmark i {
    opacity: 1;
}

.task-content {
    flex: 1;
}

.task-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 10px;
}

.task-title {
    font-weight: 600;
    font-size: 1.1rem;
    color: var(--text-color);
    margin-bottom: 5px;
}

.task-item.completed .task-title {
    text-decoration: line-through;
    color: var(--gray-color);
}

.task-priority {
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.priority-high {
    background: rgba(231, 76, 60, 0.2);
    color: var(--danger-color);
}

.priority-medium {
    background: rgba(243, 156, 18, 0.2);
    color: var(--warning-color);
}

.priority-low {
    background: rgba(46, 204, 113, 0.2);
    color: var(--secondary-color);
}

.task-description {
    color: var(--gray-color);
    font-size: 0.95rem;
    margin-bottom: 15px;
    line-height: 1.5;
}

.task-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 10px;
}

.task-category {
    display: inline-flex;
    align-items: center;
    gap: 5px;
    padding: 4px 12px;
    background: rgba(52, 152, 219, 0.1);
    color: var(--primary-color);
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 500;
}

.task-due-date {
    display: inline-flex;
    align-items: center;
    gap: 5px;
    font-size: 0.9rem;
    color: var(--gray-color);
}

.task-due-date.overdue {
    color: var(--danger-color);
    font-weight: 500;
}

.task-due-date.today {
    color: var(--warning-color);
    font-weight: 500;
}

.task-actions {
    display: flex;
    gap: 8px;
}

.task-action-btn {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    border: none;
    background: var(--card-bg);
    color: var(--text-color);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

.task-action-btn:hover {
    background: var(--primary-color);
    color: white;
    transform: rotate(15deg);
}

.task-action-btn.delete:hover {
    background: var(--danger-color);
}

/* Bulk Actions */
.bulk-actions {
    display: flex;
    justify-content: flex-end;
    gap: 15px;
    padding: 20px;
    background: var(--card-bg);
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    z-index: 1000;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.modal.active {
    display: flex;
}

.modal-content {
    background: var(--card-bg);
    border-radius: var(--border-radius);
    width: 100%;
    max-width: 800px;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: 0 20px 50px rgba(0, 0, 0, 0.3);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 25px;
    border-bottom: 2px solid var(--border-color);
}

.modal-header h2 {
    font-size: 1.5rem;
    color: var(--text-color);
    display: flex;
    align-items: center;
    gap: 10px;
}

.close-modal {
    background: none;
    border: none;
    font-size: 2rem;
    color: var(--gray-color);
    cursor: pointer;
    transition: var(--transition);
}

.close-modal:hover {
    color: var(--danger-color);
    transform: rotate(90deg);
}

.modal-body {
    padding: 25px;
}

.stats-container {
    display: grid;
    gap: 30px;
}

.stat-chart h3,
.stat-numbers h3 {
    font-size: 1.2rem;
    margin-bottom: 20px;
    color: var(--text-color);
}

.chart-bar {
    background: var(--bg-color);
    border-radius: 8px;
    padding: 20px;
}

.bar {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 15px;
}

.bar-label {
    width: 100px;
    font-weight: 500;
    color: var(--text-color);
}

.bar-container {
    flex: 1;
    height: 25px;
    background: var(--border-color);
    border-radius: 12px;
    overflow: hidden;
}

.bar-fill {
    height: 100%;
    border-radius: 12px;
    transition: width 1s ease-in-out;
}

.bar-value {
    width: 50px;
    text-align: right;
    font-weight: 600;
    color: var(--text-color);
}

.stat-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
}

.stat-card {
    display: flex;
    align-items: center;
    gap: 20px;
    padding: 20px;
    background: var(--bg-color);
    border-radius: 10px;
}

.stat-icon {
    width: 60px;
    height: 60px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.5rem;
}

.stat-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-color);
    margin-bottom: 5px;
}

.stat-title {
    font-size: 0.9rem;
    color: var(--gray-color);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

/* Footer */
.footer {
    text-align: center;
    padding: 25px 0;
    border-top: 2px solid var(--border-color);
    color: var(--gray-color);
    font-size: 0.9rem;
}

.footer-note {
    font-size: 0.85rem;
    color: var(--primary-color);
    margin-top: 10px;
}

/* Responsive Design */
@media (max-width: 1024px) {
    .main-content {
        grid-template-columns: 1fr;
    }
    
    .left-panel {
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
        gap: 25px;
    }
    
    .card {
        margin-bottom: 0;
    }
}

@media (max-width: 768px) {
    .container {
        padding: 15px;
    }
    
    .header {
        flex-direction: column;
        gap: 20px;
        text-align: center;
    }
    
    .logo {
        flex-direction: column;
        gap: 10px;
    }
    
    .tagline {
        margin-left: 0;
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .task-list-header {
        flex-direction: column;
        gap: 20px;
        text-align: center;
    }
    
    .search-box {
        width: 100%;
    }
    
    .bulk-actions {
        flex-direction: column;
    }
    
    .modal-content {
        margin: 20px;
    }
}

@media (max-width: 480px) {
    .card {
        padding: 20px;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
    }
    
    .stat-grid {
        grid-template-columns: 1fr;
    }
    
    .priority-filters {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .task-header {
        flex-direction: column;
        gap: 10px;
    }
    
    .task-meta {
        flex-direction: column;
        align-items: flex-start;
    }
}