:root {
    --bg-primary: #f5f5f5;
    --bg-secondary: #ffffff;
    --bg-tertiary: #f8f9fa;
    --text-primary: #2c3e50;
    --text-secondary: #333333;
    --text-muted: #666666;
    --border-color: #ddd;
    --border-light: #eee;
    --shadow: 0 2px 5px rgba(0,0,0,0.1);
    --shadow-lg: 0 4px 20px rgba(0,0,0,0.2);
    --btn-primary: #3498db;
    --btn-primary-hover: #2980b9;
    --btn-success: #27ae60;
    --btn-success-hover: #2ecc71;
    --btn-danger: #e74c3c;
    --btn-warning: #f39c12;
    --btn-secondary: #95a5a6;
    --btn-secondary-hover: #7f8c8d;
    --overlay: rgba(0,0,0,0.5);
}

[data-theme="dark"] {
    --bg-primary: #1a1a2e;
    --bg-secondary: #16213e;
    --bg-tertiary: #0f3460;
    --text-primary: #e8e8e8;
    --text-secondary: #d4d4d4;
    --text-muted: #a0a0a0;
    --border-color: #2a2a4a;
    --border-light: #1e1e3a;
    --shadow: 0 2px 5px rgba(0,0,0,0.3);
    --shadow-lg: 0 4px 20px rgba(0,0,0,0.4);
    --overlay: rgba(0,0,0,0.7);
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: var(--text-secondary);
    background-color: var(--bg-primary);
    transition: background-color 0.3s, color 0.3s;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--border-color);
}

h1 {
    color: var(--text-primary);
}

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

button {
    padding: 8px 16px;
    background-color: var(--btn-primary);
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 14px;
    transition: background-color 0.3s;
}

button:hover {
    background-color: var(--btn-primary-hover);
}

#addIssueBtn {
    background-color: var(--btn-success);
}

#addIssueBtn:hover {
    background-color: var(--btn-success-hover);
}

#langToggle, #themeToggle {
    padding: 8px 12px;
    font-size: 16px;
    min-width: 40px;
}

.view {
    display: none;
}

.view.active {
    display: block;
}

.filters {
    display: flex;
    gap: 15px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.filters select,
.filters input {
    padding: 8px 12px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 14px;
    background-color: var(--bg-secondary);
    color: var(--text-secondary);
}

.filters input {
    flex: 1;
    min-width: 200px;
}

table {
    width: 100%;
    border-collapse: collapse;
    background: var(--bg-secondary);
    box-shadow: var(--shadow);
}

th, td {
    padding: 12px 15px;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

th {
    background-color: var(--bg-tertiary);
    font-weight: 600;
    color: var(--text-primary);
}

tr:hover {
    background-color: var(--bg-tertiary);
}

.issue-row {
    cursor: pointer;
}

.issue-row.parent-row {
    font-weight: 600;
}

.issue-row.child-row {
    background-color: rgba(0,0,0,0.02);
}

[data-theme="dark"] .issue-row.child-row {
    background-color: rgba(255,255,255,0.03);
}

.issue-row.dragging {
    opacity: 0.4;
    background: var(--bg-tertiary);
}

.issue-row.drag-over {
    border-top: 2px solid var(--btn-primary);
}

.drag-handle {
    cursor: grab;
    margin-right: 6px;
    color: var(--text-muted);
    font-size: 14px;
    user-select: none;
}

.drag-handle:hover {
    color: var(--text-primary);
}

.issue-row:active .drag-handle {
    cursor: grabbing;
}

.child-indent {
    display: inline-block;
}

.child-indent-1 { padding-left: 20px; }
.child-indent-2 { padding-left: 40px; }
.child-indent-3 { padding-left: 60px; }

.expand-btn {
    display: inline-block;
    width: 20px;
    height: 20px;
    line-height: 20px;
    text-align: center;
    cursor: pointer;
    margin-right: 5px;
    font-size: 12px;
    border-radius: 3px;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
}

.status {
    display: inline-block;
    padding: 4px 8px;
    border-radius: 12px;
    font-size: 12px;
    font-weight: 500;
}

.status.backlog {
    background-color: #9b59b6;
    color: white;
}

.status.todo {
    background-color: #e74c3c;
    color: white;
}

.status.in_progress {
    background-color: #f39c12;
    color: white;
}

.status.done {
    background-color: #27ae60;
    color: white;
}

.priority {
    display: inline-block;
    padding: 4px 8px;
    border-radius: 12px;
    font-size: 12px;
    font-weight: 500;
}

.priority.low {
    background-color: #95a5a6;
    color: white;
}

.priority.medium {
    background-color: #f39c12;
    color: white;
}

.priority.high {
    background-color: #e74c3c;
    color: white;
}

.actions {
    display: flex;
    gap: 5px;
    flex-wrap: wrap;
}

.actions button {
    padding: 5px 10px;
    font-size: 12px;
}

.actions button:first-child {
    background-color: var(--btn-primary);
}

.actions button:nth-child(2) {
    background-color: var(--btn-success);
}

.actions button:nth-child(3) {
    background-color: var(--btn-warning);
}

.actions button:nth-child(4) {
    background-color: var(--btn-danger);
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: var(--overlay);
}

.modal-content {
    background-color: var(--bg-secondary);
    margin: 3vh auto;
    padding: 24px;
    border-radius: 8px;
    width: 92%;
    max-width: 600px;
    position: relative;
    box-shadow: var(--shadow-lg);
    max-height: 94vh;
    overflow-y: auto;
}

.modal-lg {
    max-width: 700px;
}

.close {
    position: absolute;
    right: 16px;
    top: 12px;
    font-size: 24px;
    font-weight: bold;
    cursor: pointer;
    color: var(--text-muted);
}

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

.form-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 14px 16px;
    margin-bottom: 20px;
}

.form-col-full {
    grid-column: 1 / -1;
}

.form-col-2 {
    grid-column: span 1;
}

.form-col-3 {
    grid-column: span 1;
}

.form-grid label {
    display: block;
    margin-bottom: 4px;
    font-weight: 500;
    font-size: 13px;
    color: var(--text-primary);
}

.form-grid input,
.form-grid textarea,
.form-grid select {
    width: 100%;
    padding: 8px 10px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 13px;
    background-color: var(--bg-primary);
    color: var(--text-secondary);
}

.md-hint {
    font-weight: 400;
    font-size: 11px;
    color: var(--text-muted);
}

.md-editor {
    border: 1px solid var(--border-color);
    border-radius: 4px;
    overflow: hidden;
}

.md-toolbar {
    display: flex;
    gap: 2px;
    padding: 4px 6px;
    background: var(--bg-tertiary);
    border-bottom: 1px solid var(--border-color);
}

.md-toolbar button {
    padding: 4px 8px;
    font-size: 12px;
    background: transparent;
    color: var(--text-secondary);
    border: 1px solid transparent;
    border-radius: 3px;
    cursor: pointer;
    min-width: 28px;
    height: 26px;
}

.md-toolbar button:hover {
    background: var(--bg-secondary);
    border-color: var(--border-color);
}

.md-preview-btn {
    margin-left: auto;
}

.md-editor textarea {
    border: none;
    border-radius: 0;
    resize: vertical;
    min-height: 60px;
    font-family: 'Consolas', 'Monaco', monospace;
    font-size: 12px;
    line-height: 1.5;
}

.md-editor textarea:focus {
    outline: none;
}

.md-preview {
    padding: 10px;
    min-height: 60px;
    font-size: 13px;
    line-height: 1.6;
    background: var(--bg-primary);
}

.md-preview h1, .md-preview h2, .md-preview h3 {
    margin: 8px 0 4px;
}

.md-preview p {
    margin: 4px 0;
}

.md-preview code {
    background: var(--bg-tertiary);
    padding: 2px 4px;
    border-radius: 3px;
    font-size: 12px;
}

.md-preview pre {
    background: var(--bg-tertiary);
    padding: 8px;
    border-radius: 4px;
    overflow-x: auto;
}

.md-preview pre code {
    background: transparent;
    padding: 0;
}

.md-preview ul, .md-preview ol {
    margin: 4px 0;
    padding-left: 20px;
}

.md-preview a {
    color: var(--btn-primary);
}

.md-preview blockquote {
    border-left: 3px solid var(--border-color);
    margin: 4px 0;
    padding: 4px 10px;
    color: var(--text-muted);
}

.form-actions {
    display: flex;
    justify-content: flex-end;
    gap: 10px;
    margin-top: 16px;
    padding-top: 16px;
    border-top: 1px solid var(--border-color);
}

.form-actions button {
    padding: 8px 20px;
}

#cancelBtn {
    background-color: var(--btn-secondary);
}

#cancelBtn:hover {
    background-color: var(--btn-secondary-hover);
}

/* View Detail */
.view-detail {
    padding: 4px 0;
}

.view-row {
    display: flex;
    align-items: center;
    padding: 8px 0;
    border-bottom: 1px solid var(--border-light);
    font-size: 14px;
}

.view-label {
    width: 80px;
    flex-shrink: 0;
    font-weight: 500;
    color: var(--text-muted);
    font-size: 13px;
}

.view-desc {
    padding: 10px 0;
}

.view-desc .view-label {
    display: block;
    width: auto;
    margin-bottom: 6px;
}

.view-desc .md-preview {
    padding: 10px;
    background: var(--bg-tertiary);
    border-radius: 4px;
    font-size: 14px;
    line-height: 1.6;
}

.view-subtasks {
    padding: 10px 0;
}

.view-subtasks .view-label {
    display: block;
    width: auto;
    margin-bottom: 6px;
}

.view-subtasks ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.view-subtasks li {
    padding: 6px 0;
    border-bottom: 1px solid var(--border-light);
    display: flex;
    align-items: center;
    gap: 8px;
}

.view-detail .form-actions {
    margin-top: 16px;
    padding-top: 16px;
    border-top: 1px solid var(--border-color);
}

.view-detail .form-actions button {
    padding: 8px 16px;
    font-size: 13px;
}

.date-picker {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.date-picker input {
    width: 100%;
}

.date-quick-btns {
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
}

.date-quick-btns button {
    padding: 4px 10px;
    font-size: 12px;
    background-color: var(--bg-tertiary);
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    cursor: pointer;
    transition: all 0.2s;
}

.date-quick-btns button:hover {
    background-color: var(--btn-primary);
    color: white;
    border-color: var(--btn-primary);
}

.date-quick-btns button.tbd-btn {
    background-color: #e67e22;
    color: white;
    border-color: #e67e22;
    font-weight: 600;
}

.date-quick-btns button.tbd-btn:hover {
    background-color: #d35400;
    border-color: #d35400;
}

/* Gantt */
.gantt-controls {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
    align-items: center;
}

.gantt-tooltip {
    position: fixed;
    z-index: 9999;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 16px 20px;
    max-width: 500px;
    max-height: 400px;
    overflow-y: auto;
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
    font-size: 14px;
    line-height: 1.6;
    color: var(--text-secondary);
    pointer-events: none;
    display: none;
}

.gantt-tooltip h1, .gantt-tooltip h2, .gantt-tooltip h3 {
    margin: 6px 0 4px;
    font-size: 14px;
}

.gantt-tooltip p {
    margin: 4px 0;
}

.gantt-tooltip code {
    background: var(--bg-tertiary);
    padding: 1px 4px;
    border-radius: 3px;
    font-size: 12px;
}

.gantt-tooltip pre {
    background: var(--bg-tertiary);
    padding: 6px;
    border-radius: 4px;
    overflow-x: auto;
    font-size: 11px;
}

.gantt-tooltip ul, .gantt-tooltip ol {
    margin: 4px 0;
    padding-left: 16px;
}

.gantt-tooltip a {
    color: var(--btn-primary);
}

.gantt-tooltip blockquote {
    border-left: 2px solid var(--border-color);
    padding-left: 8px;
    color: var(--text-muted);
}

#currentScale {
    margin-left: auto;
    font-weight: 500;
}

.gantt-container {
    display: flex;
    background: var(--bg-secondary);
    box-shadow: var(--shadow);
    border-radius: 4px;
    overflow: hidden;
}

.gantt-sidebar {
    width: 300px;
    background: var(--bg-tertiary);
    border-right: 1px solid var(--border-color);
    flex-shrink: 0;
}

.gantt-chart {
    flex: 1;
    overflow-x: auto;
    position: relative;
}

.gantt-header {
    display: flex;
    background: var(--bg-tertiary);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 10;
}

.gantt-header-cell {
    min-width: 100px;
    padding: 10px;
    text-align: center;
    border-right: 1px solid var(--border-light);
    font-weight: 500;
    font-size: 12px;
}

.gantt-row {
    display: flex;
    border-bottom: 1px solid var(--border-light);
    height: 40px;
}

.gantt-sidebar-item {
    width: 300px;
    padding: 10px;
    border-bottom: 1px solid var(--border-light);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    height: 40px;
    display: flex;
    align-items: center;
    color: var(--text-secondary);
    font-size: 13px;
}

.gantt-sidebar-header {
    width: 300px;
    padding: 10px;
    border-bottom: 1px solid var(--border-color);
    background: var(--bg-tertiary);
    font-weight: 600;
    font-size: 13px;
    color: var(--text-primary);
    height: 40px;
    display: flex;
    align-items: center;
    position: sticky;
    top: 0;
    z-index: 10;
}

.gantt-sidebar-item.parent {
    font-weight: 600;
}

.gantt-sidebar-item.child {
    font-weight: normal;
    opacity: 0.9;
}

.gantt-sidebar-item.child-1 { padding-left: 25px; }
.gantt-sidebar-item.child-2 { padding-left: 45px; }
.gantt-sidebar-item.child-3 { padding-left: 65px; }

.gantt-bar-container {
    flex: 1;
    position: relative;
    height: 100%;
}

.gantt-bar {
    position: absolute;
    height: 24px;
    top: 8px;
    border-radius: 4px;
    cursor: pointer;
    display: flex;
    align-items: center;
    padding: 0 8px;
    font-size: 12px;
    color: white;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    transition: opacity 0.2s;
}

.gantt-bar:hover {
    opacity: 0.9;
    filter: brightness(1.1);
}

.gantt-bar.child-bar {
    height: 18px;
    top: 11px;
    font-size: 11px;
    opacity: 0.9;
}

.gantt-bar.parent-bar {
    height: 28px;
    top: 6px;
    font-weight: 600;
    border: 2px solid rgba(255,255,255,0.3);
    box-shadow: 0 2px 4px rgba(0,0,0,0.2);
}

.gantt-sidebar-item .expand-btn {
    display: inline-block;
    width: 18px;
    height: 18px;
    line-height: 18px;
    text-align: center;
    font-size: 10px;
    margin-right: 4px;
    border-radius: 3px;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    cursor: pointer;
}

.gantt-sidebar-item .expand-btn:hover {
    background: var(--btn-primary);
    color: white;
    border-color: var(--btn-primary);
}

.gantt-today {
    position: absolute;
    top: 0;
    bottom: 0;
    width: 2px;
    background-color: #e74c3c;
    z-index: 5;
}

@media (max-width: 768px) {
    .form-row {
        flex-direction: column;
        gap: 0;
    }
    
    .header-actions {
        flex-direction: column;
    }
    
    .filters {
        flex-direction: column;
    }
    
    .gantt-sidebar {
        width: 200px;
    }
    
    .gantt-sidebar-item {
        width: 200px;
    }
}