:root {
    --bg-primary: #1a1a1a;
    --bg-secondary: #2d2d2d;
    --bg-column: #252525;
    --text-primary: #ffffff;
    --text-secondary: #b3b3b3;
    --accent-color: #00bcd4;
    --accent-hover: #00acc1;
    --border-color: #404040;
    --shadow-color: rgba(0, 0, 0, 0.3);
    --danger-color: #f44336;
    --success-color: #4caf50;
    --warning-color: #ff9800;
    --info-color: #2196f3;
    --low-priority: #4caf50;
    --medium-priority: #ff9800;
    --high-priority: #f44336;
    --overdue-color: #f44336;
    --due-soon-color: #ff9800;
    --header-bg: #2d2d2d;
    --dropdown-bg: #2d2d2d;
    --dropdown-hover: #3d3d3d;
}

/* Light theme */
[data-theme="light"] {
    --bg-primary: #f5f5f5;
    --bg-secondary: #ffffff;
    --bg-column: #ffffff;
    --text-primary: #333333;
    --text-secondary: #666666;
    --border-color: #e0e0e0;
    --shadow-color: rgba(0, 0, 0, 0.1);
    --header-bg: #ffffff;
    --dropdown-bg: #ffffff;
    --dropdown-hover: #f5f5f5;
}

/* Dark theme (default) */
[data-theme="dark"] {
    --bg-primary: #1a1a1a;
    --bg-secondary: #2d2d2d;
    --bg-column: #252525;
    --text-primary: #ffffff;
    --text-secondary: #b3b3b3;
    --border-color: #404040;
    --shadow-color: rgba(0, 0, 0, 0.3);
    --header-bg: #2d2d2d;
    --dropdown-bg: #2d2d2d;
    --dropdown-hover: #3d3d3d;
}

/* High contrast theme */
[data-theme="high-contrast"] {
    --bg-primary: #000000;
    --bg-secondary: #000000;
    --bg-column: #000000;
    --text-primary: #ffff00;
    --text-secondary: #ffffff;
    --border-color: #ffff00;
    --shadow-color: rgba(255, 255, 0, 0.3);
    --accent-color: #ffff00;
    --accent-hover: #ffff00;
    --header-bg: #000000;
    --dropdown-bg: #000000;
    --dropdown-hover: #333333;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
    width: 100%;
    max-width: 1400px;
}

/* Header */
header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    padding: 20px;
    background-color: var(--header-bg);
    border-radius: 10px;
    box-shadow: 0 4px 6px var(--shadow-color);
}

.header-left h1 {
    font-size: 24px;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 10px;
}

.header-left h1 i {
    color: var(--accent-color);
}

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

/* Search box */
.search-box {
    position: relative;
    display: flex;
    align-items: center;
}

.search-box i {
    position: absolute;
    left: 10px;
    color: var(--text-secondary);
}

.search-box input {
    padding: 10px 10px 10px 35px;
    border: 1px solid var(--border-color);
    border-radius: 5px;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    width: 250px;
    font-size: 14px;
}

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

/* Theme toggle */
.btn-theme {
    background: none;
    border: none;
    color: var(--text-primary);
    font-size: 20px;
    cursor: pointer;
    padding: 8px;
    border-radius: 50%;
    transition: background-color 0.3s ease;
}

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

/* Dropdown */
.dropdown {
    position: relative;
    display: inline-block;
}

.btn-dropdown {
    background: none;
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 8px 12px;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

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

.dropdown-content {
    display: none;
    position: absolute;
    right: 0;
    background-color: var(--dropdown-bg);
    min-width: 160px;
    box-shadow: 0 8px 16px var(--shadow-color);
    border-radius: 5px;
    z-index: 1;
}

.dropdown-content a {
    color: var(--text-primary);
    padding: 12px 16px;
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 10px;
    transition: background-color 0.3s ease;
}

.dropdown-content a:hover {
    background-color: var(--dropdown-hover);
}

.dropdown:hover .dropdown-content {
    display: block;
}

/* Filters bar */
.filters-bar {
    display: flex;
    gap: 15px;
    margin-bottom: 20px;
    padding: 15px;
    background-color: var(--bg-secondary);
    border-radius: 8px;
    align-items: center;
    flex-wrap: wrap;
}

.filter-group {
    display: flex;
    align-items: center;
    gap: 8px;
}

.filter-group label {
    color: var(--text-secondary);
    font-size: 14px;
}

.filter-group select {
    padding: 8px;
    border: 1px solid var(--border-color);
    border-radius: 5px;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    font-size: 14px;
}

.btn-clear-filters {
    padding: 8px 12px;
    background-color: var(--danger-color);
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 14px;
    display: flex;
    align-items: center;
    gap: 5px;
    transition: opacity 0.3s ease;
}

.btn-clear-filters:hover {
    opacity: 0.8;
}

/* Board */
.board {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
}

.column {
    background-color: var(--bg-column);
    border-radius: 10px;
    padding: 20px;
    min-height: 500px;
    box-shadow: 0 4px 6px var(--shadow-color);
}

.column-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 2px solid var(--border-color);
}

.column-header h2 {
    font-size: 18px;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 8px;
}

.column-header i {
    color: var(--accent-color);
}

.task-count {
    background-color: var(--bg-secondary);
    padding: 4px 10px;
    border-radius: 15px;
    font-size: 14px;
    font-weight: 500;
}

.tasks-container {
    min-height: 400px;
}

/* Task Card */
.task-card {
    background-color: var(--bg-secondary);
    border-radius: 8px;
    padding: 15px;
    margin-bottom: 15px;
    cursor: move;
    transition: transform 0.2s ease, box-shadow 0.2s ease, opacity 0.3s ease;
    border-left: 4px solid transparent;
    position: relative;
}
.task-card {
    transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.task-card.dragging {
    opacity: 0.6;
    transform: rotate(3deg) scale(1.05);
}

.column.drag-over {
    background: rgba(255,255,255,0.05);
    border: 2px dashed #6c63ff;
}

.task-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px var(--shadow-color);
}

.task-card.dragging {
    opacity: 0.5;
    transform: scale(0.98);
}

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

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

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

.task-card.overdue {
    border-left-color: var(--overdue-color);
    background-color: rgba(244, 67, 54, 0.1);
}

.task-card.due-soon {
    border-left-color: var(--due-soon-color);
}

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

.task-title {
    font-size: 16px;
    font-weight: 600;
    word-break: break-word;
    flex: 1;
}

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

.task-actions button {
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    font-size: 14px;
    padding: 4px;
    transition: color 0.2s ease;
}

.task-actions button:hover {
    color: var(--text-primary);
}

.task-actions .edit-task:hover {
    color: var(--accent-color);
}

.task-actions .delete-task:hover {
    color: var(--danger-color);
}

.task-description {
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: 10px;
    word-break: break-word;
}

.task-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 5px;
    margin-bottom: 10px;
}

.task-tag {
    background-color: var(--bg-primary);
    color: var(--text-secondary);
    padding: 3px 8px;
    border-radius: 12px;
    font-size: 11px;
    display: flex;
    align-items: center;
    gap: 3px;
}

.task-tag i {
    font-size: 10px;
}

.task-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 12px;
}

.task-priority {
    padding: 4px 8px;
    border-radius: 4px;
    font-weight: 500;
}

.priority-low {
    background-color: rgba(76, 175, 80, 0.2);
    color: var(--low-priority);
}

.priority-medium {
    background-color: rgba(255, 152, 0, 0.2);
    color: var(--medium-priority);
}

.priority-high {
    background-color: rgba(244, 67, 54, 0.2);
    color: var(--high-priority);
}

.task-date, .task-due-date {
    display: flex;
    align-items: center;
    gap: 3px;
    color: var(--text-secondary);
}

.task-due-date.overdue {
    color: var(--overdue-color);
}

.task-due-date.due-soon {
    color: var(--due-soon-color);
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.7);
    z-index: 1000;
    justify-content: center;
    align-items: center;
}

.modal.show {
    display: flex;
}

.modal-content {
    background-color: var(--bg-secondary);
    border-radius: 10px;
    width: 90%;
    max-width: 600px;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: 0 4px 20px var(--shadow-color);
}

.modal-content.modal-sm {
    max-width: 400px;
}

.modal-header {
    padding: 20px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-header h3 {
    font-size: 20px;
    font-weight: 600;
}

.close-modal {
    font-size: 24px;
    cursor: pointer;
    color: var(--text-secondary);
    transition: color 0.2s ease;
}

.close-modal:hover {
    color: var(--text-primary);
}

#taskForm {
    padding: 20px;
}

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

.form-row {
    display: flex;
    gap: 15px;
}

.form-group.half {
    flex: 1;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--text-secondary);
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 10px;
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: 5px;
    color: var(--text-primary);
    font-size: 14px;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--accent-color);
}

.modal-footer {
    display: flex;
    justify-content: flex-end;
    gap: 10px;
    margin-top: 20px;
}

.btn-cancel,
.btn-save,
.btn-add-task {
    padding: 10px 20px;
    border: none;
    border-radius: 5px;
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: background-color 0.2s ease;
}

.btn-cancel {
    background-color: var(--bg-primary);
    color: var(--text-secondary);
}

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

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

.btn-save:hover {
    background-color: var(--accent-hover);
}

.btn-add-task {
    background-color: var(--accent-color);
    color: white;
    display: flex;
    align-items: center;
    gap: 8px;
}

.btn-add-task:hover {
    background-color: var(--accent-hover);
}

.modal-body {
    padding: 20px;
    text-align: center;
}

/* Flatpickr customization */
.flatpickr-calendar {
    background-color: var(--bg-secondary) !important;
    border: 1px solid var(--border-color) !important;
    box-shadow: 0 4px 20px var(--shadow-color) !important;
}

.flatpickr-months,
.flatpickr-weekdays,
.flatpickr-current-month {
    background-color: var(--bg-secondary) !important;
}

.flatpickr-day {
    color: var(--text-primary) !important;
}

.flatpickr-day:hover {
    background-color: var(--border-color) !important;
}

.flatpickr-day.selected {
    background-color: var(--accent-color) !important;
    border-color: var(--accent-color) !important;
}

/* Responsive */
@media (max-width: 1024px) {
    .board {
        grid-template-columns: 1fr;
    }
    
    header {
        flex-direction: column;
        gap: 15px;
        text-align: center;
    }
    
    .header-right {
        flex-wrap: wrap;
        justify-content: center;
    }
    
    .filters-bar {
        flex-direction: column;
        align-items: stretch;
    }
    
    .search-box input {
        width: 100%;
    }
}