/* ========== Global Styles ========== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Microsoft YaHei', 'PingFang SC', sans-serif;
    background: #f0f2f5;
    color: #333;
    overflow: hidden;
}

.app-container {
    display: flex;
    height: 100vh;
    width: 100vw;
}

/* ========== Left Sidebar ========== */
.sidebar {
    width: 220px;
    min-width: 220px;
    background: #fff;
    color: #303133;
    display: flex;
    flex-direction: column;
    box-shadow: 2px 0 8px rgba(0, 0, 0, 0.06);
    z-index: 10;
}

.sidebar-header {
    padding: 20px 16px;
    text-align: center;
    border-bottom: 1px solid #ebeef5;
}

.sidebar-header h1 {
    font-size: 20px;
    font-weight: 600;
    letter-spacing: 2px;
    color: #303133;
}

.sidebar-nav {
    flex: 1;
    padding: 10px 0;
}

.sidebar-nav ul {
    list-style: none;
}

.nav-item {
    display: flex;
    align-items: center;
    padding: 14px 20px;
    cursor: pointer;
    transition: all 0.3s ease;
    border-left: 3px solid transparent;
    font-size: 14px;
    gap: 10px;
    color: #606266;
}

.nav-item:hover {
    background: #f5f7fa;
    border-left-color: #dcdfe6;
    color: #409eff;
}

.nav-item.active {
    background: #ecf5ff;
    border-left-color: #409eff;
    color: #409eff;
}

.nav-icon {
    font-size: 18px;
    width: 24px;
    text-align: center;
}

.nav-text {
    flex: 1;
}

.search-box {
    padding: 12px 16px;
    border-top: 1px solid #ebeef5;
}

.search-box input {
    width: 100%;
    padding: 8px 12px;
    border-radius: 6px;
    border: 1px solid #dcdfe6;
    background: #f5f7fa;
    color: #303133;
    font-size: 13px;
    outline: none;
    transition: border-color 0.3s;
}

.search-box input::placeholder {
    color: #c0c4cc;
}

.search-box input:focus {
    border-color: #409eff;
    background: #fff;
}


/* ========== Sidebar Import/Export ========== */
.sidebar-import-export {
    padding: 12px 16px;
    border-top: 1px solid #ebeef5;
}

.sidebar-btn {
    display: block;
    width: 100%;
    padding: 8px 12px;
    margin-bottom: 6px;
    border: 1px solid #dcdfe6;
    border-radius: 6px;
    background: #fff;
    color: #606266;
    font-size: 13px;
    cursor: pointer;
    transition: all 0.2s;
    text-align: center;
}

.sidebar-btn:hover {
    background: #f5f7fa;
    border-color: #409eff;
    color: #409eff;
}

.sidebar-btn:last-child {
    margin-bottom: 0;
}

.btn-export-data:hover {
    border-color: #67c23a;
    color: #67c23a;
    background: #f0f9eb;
}

.btn-import-data:hover {
    border-color: #e6a23c;
    color: #e6a23c;
    background: #fdf6ec;
}

.import-status {
    font-size: 12px;
    text-align: center;
    padding: 4px 0;
    color: #909399;
}

.progress-overlay {
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(0,0,0,0.4);
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
}
.progress-modal {
    background: #fff;
    border-radius: 8px;
    padding: 24px 32px;
    min-width: 300px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.2);
    text-align: center;
}
.progress-title {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 16px;
    color: #303133;
}
.progress-bar-bg {
    height: 8px;
    background: #e4e7ed;
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 8px;
}
.export-menu {
    position: fixed;
    background: #fff;
    border: 1px solid #e4e7ed;
    border-radius: 6px;
    box-shadow: 0 4px 16px rgba(0,0,0,0.12);
    z-index: 500;
    min-width: 160px;
    overflow: hidden;
}
.export-menu-title {
    padding: 8px 14px;
    font-size: 12px;
    color: #909399;
    border-bottom: 1px solid #ebeef5;
    background: #f9fafb;
}
.export-menu-item {
    padding: 10px 14px;
    font-size: 13px;
    color: #606266;
    cursor: pointer;
    transition: background 0.15s;
}
.export-menu-item:hover {
    background: #ecf5ff;
    color: #409eff;
}
.export-menu-item.cancel {
    border-top: 1px solid #ebeef5;
    color: #909399;
}
.export-menu-item.cancel:hover {
    background: #f5f7fa;
    color: #909399;
}
.progress-bar-fill {
    height: 100%;
    background: linear-gradient(90deg, #409eff, #66b1ff);
    border-radius: 4px;
    transition: width 0.2s;
}
.progress-text {
    font-size: 13px;
    color: #909399;
}
.filter-bar {
    background: #fff;
    border-bottom: 1px solid #ebeef5;
    padding: 0;
}
.filter-bar-toggle {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 8px 16px;
    font-size: 13px;
    font-weight: 600;
    color: #606266;
    cursor: pointer;
    user-select: none;
    background: #f9fafb;
    border-bottom: 1px solid #ebeef5;
}
.filter-bar-toggle:hover {
    background: #f0f2f5;
}
.filter-bar.collapsed .filter-bar-toggle {
    border-bottom: none;
}
.filter-bar-body {
    overflow: hidden;
}
.filter-bar.collapsed .filter-bar-body {
    display: none;
}
.filter-bar-row {
    display: flex;
    align-items: center;
    padding: 6px 16px;
    font-size: 13px;
    border-bottom: 1px solid #f0f0f0;
}
.filter-bar-row:last-child {
    border-bottom: none;
}
.filter-bar-label {
    color: #606266;
    white-space: nowrap;
    margin-right: 12px;
    font-weight: 600;
    font-size: 12px;
    min-width: 40px;
    flex-shrink: 0;
}
.filter-bar-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    flex: 1;
}
.filter-tag {
    display: inline-block;
    padding: 3px 12px;
    border-radius: 4px;
    border: 1px solid #dcdfe6;
    background: #fff;
    color: #606266;
    cursor: pointer;
    font-size: 12px;
    transition: all 0.2s;
    user-select: none;
}
.filter-tag:hover {
    background: #f5f7fa;
    color: #409eff;
    border-color: #c6e2ff;
}
.filter-tag.active {
    background: #ecf5ff;
    border-color: #409eff;
    color: #409eff;
    font-weight: 500;
}
.filter-tag .tag-count {
    font-size: 11px;
    opacity: 0.6;
    margin-left: 2px;
}

/* ========== Center Knowledge Panel ========== */
.knowledge-panel {
    width: 240px;
    min-width: 240px;
    background: #fff;
    border-right: 1px solid #e4e7ed;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.panel-header {
    padding: 16px 20px;
    border-bottom: 1px solid #ebeef5;
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: #fafafa;
}

.panel-header h2 {
    font-size: 16px;
    font-weight: 600;
    color: #303133;
}

.question-count {
    font-size: 12px;
    color: #909399;
    flex: 1;
}

.btn-clear-all {
    font-size: 12px;
    padding: 4px 10px;
    border: 1px solid #f56c6c;
    border-radius: 4px;
    background: #fff;
    color: #f56c6c;
    cursor: pointer;
    white-space: nowrap;
    margin-left: 10px;
}
.btn-clear-all:hover {
    background: #fef0f0;
}

.knowledge-list {
    flex: 1;
    overflow-y: auto;
    padding: 10px 0;
}

.knowledge-list::-webkit-scrollbar {
    width: 4px;
}

.knowledge-list::-webkit-scrollbar-thumb {
    background: #dcdfe6;
    border-radius: 2px;
}

.knowledge-category {
    margin-bottom: 4px;
}

.category-title {
    padding: 10px 20px 6px;
    font-size: 13px;
    font-weight: 600;
    color: #606266;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 6px;
    user-select: none;
}
.category-title.active {
    color: #409eff;
}

.category-title::before {
    content: '\25be';
    font-size: 10px;
    transition: transform 0.2s;
}

.category-title.collapsed::before {
    transform: rotate(-90deg);
}

.category-items {
    list-style: none;
    padding: 0 8px 8px 20px;
    transition: max-height 0.3s ease;
    overflow: hidden;
}

.category-items.hidden {
    max-height: 0 !important;
    padding: 0 8px;
}

.knowledge-item {
    padding: 8px 12px;
    font-size: 13px;
    color: #606266;
    cursor: pointer;
    border-radius: 4px;
    transition: all 0.2s;
    margin: 2px 0;
}

.knowledge-item:hover {
    background: #f5f7fa;
    color: #409eff;
}

.knowledge-item.active {
    background: #ecf5ff;
    color: #409eff;
    font-weight: 500;
}

.knowledge-folder .folder-icon {
    display: inline-block;
    transition: transform 0.2s;
    font-size: 10px;
    width: 14px;
    text-align: center;
    flex-shrink: 0;
}

.knowledge-folder.expanded .folder-icon {
    transform: rotate(90deg);
}

.sub-items {
    list-style: none;
    padding: 0 8px 4px 16px;
    transition: max-height 0.3s ease;
    overflow: hidden;
}

.sub-items.hidden {
    max-height: 0 !important;
    padding: 0 8px;
}

/* ========== Right Question Panel ========== */
.question-panel {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    background: #f5f7fa;
}

/* ========== 录题中心 - Question Entry Panel ========== */
.question-entry-layout {
    flex: 1;
    display: flex;
    overflow: hidden;
}

.question-entry-input {
    width: 35%;
    min-width: 340px;
    display: flex;
    flex-direction: column;
    padding: 20px;
    overflow-y: auto;
    background: #fff;
    border-right: 1px solid #e8ecf0;
}

.question-entry-input .input-card {
    background: #f8faff;
    border: 1px solid #e8ecf0;
    border-radius: 10px;
    padding: 16px;
    flex: 1;
    display: flex;
    flex-direction: column;
}

.question-entry-input .section-header {
    font-size: 15px;
    font-weight: 600;
    color: #2c3e50;
    margin: 0 0 4px 0;
    display: flex;
    align-items: center;
    gap: 6px;
}

.question-entry-input .section-header .accent-blue {
    color: #409eff;
}

.question-entry-input .section-desc {
    font-size: 12px;
    color: #909399;
    margin: 0 0 12px 0;
    line-height: 1.5;
}

.question-entry-input #latexInput {
    width: 100%;
    flex: 1;
    min-height: 180px;
    font-family: Consolas, 'Courier New', monospace;
    font-size: 13px;
    line-height: 1.6;
    padding: 12px;
    border: 1px solid #dcdfe6;
    border-radius: 6px;
    resize: vertical;
    box-sizing: border-box;
    background: #fafbfc;
    color: #2c3e50;
    transition: border-color 0.25s, box-shadow 0.25s;
    outline: none;
}

.question-entry-input #latexInput:focus {
    border-color: #409eff;
    box-shadow: 0 0 0 3px rgba(64,158,255,0.1);
    background: #fff;
}

.question-entry-input #latexInput::placeholder {
    color: #c0c4cc;
}

.question-entry-input .input-actions {
    margin-top: 12px;
    display: flex;
    gap: 8px;
    align-items: center;
    flex-wrap: wrap;
}

.question-entry-input .input-actions .btn-submit {
    background: linear-gradient(135deg, #409eff, #337ecc);
    color: #fff;
    border: none;
    border-radius: 6px;
    padding: 8px 18px;
    font-size: 13px;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 4px;
    transition: opacity 0.2s, transform 0.15s;
}

.question-entry-input .input-actions .btn-submit:hover {
    opacity: 0.9;
    transform: translateY(-1px);
}

.question-entry-input .input-actions .btn-submit:active {
    transform: translateY(0);
}

.question-entry-input .input-actions .btn-import {
    background: #fff;
    border: 1px solid #dcdfe6;
    border-radius: 6px;
    padding: 7px 14px;
    font-size: 13px;
    cursor: pointer;
    color: #606266;
    display: inline-flex;
    align-items: center;
    gap: 4px;
    transition: border-color 0.2s, color 0.2s;
}

.question-entry-input .input-actions .btn-import:hover {
    border-color: #409eff;
    color: #409eff;
}

.question-entry-input .input-actions .btn-reset {
    background: #fff;
    border: 1px solid #dcdfe6;
    border-radius: 6px;
    padding: 7px 14px;
    font-size: 13px;
    cursor: pointer;
    color: #909399;
    display: inline-flex;
    align-items: center;
    gap: 4px;
    transition: border-color 0.2s, color 0.2s;
}

.question-entry-input .input-actions .btn-reset:hover {
    border-color: #f56c6c;
    color: #f56c6c;
}

.question-entry-input .input-actions .btn-pdf {
    background: #fff;
    border: 1px solid #e6a23c;
    border-radius: 6px;
    padding: 7px 14px;
    font-size: 13px;
    cursor: pointer;
    color: #e6a23c;
    display: inline-flex;
    align-items: center;
    gap: 4px;
    transition: background 0.2s, color 0.2s;
}

.question-entry-input .input-actions .btn-pdf:hover {
    background: #e6a23c;
    color: #fff;
}

.question-entry-input .input-actions .btn-pdf:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.question-entry-input .input-actions .parse-status {
    font-size: 12px;
    color: #909399;
    margin-left: auto;
}

.question-entry-preview {
    flex: 1;
    display: flex;
    flex-direction: column;
    padding: 20px;
    overflow-y: auto;
    background: #f5f7fa;
}

.question-entry-preview .preview-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin: 0 0 12px 0;
}

.question-entry-preview .preview-header h3 {
    font-size: 15px;
    font-weight: 600;
    color: #2c3e50;
    display: flex;
    align-items: center;
    gap: 6px;
    margin: 0;
}

.question-entry-preview .preview-header h3 .accent-green {
    color: #67c23a;
}

.question-entry-preview .preview-header .preview-count {
    font-size: 12px;
    color: #909399;
    font-weight: 400;
    margin-left: 8px;
}

.question-entry-preview #parsePreview {
    flex: 1;
    overflow-y: auto;
}

.question-entry-preview .preview-placeholder {
    text-align: center;
    color: #c0c4cc;
    padding: 80px 20px;
}

.question-entry-preview .preview-placeholder .placeholder-icon {
    font-size: 48px;
    margin-bottom: 12px;
    opacity: 0.5;
}

.question-entry-preview .preview-placeholder p {
    font-size: 14px;
    margin: 0;
}

.question-cards {
    flex: 1;
    overflow-y: auto;
    padding: 16px;
}

.question-cards::-webkit-scrollbar {
    width: 6px;
}

.question-cards::-webkit-scrollbar-thumb {
    background: #dcdfe6;
    border-radius: 3px;
}

.question-cards::-webkit-scrollbar-track {
    background: transparent;
}

/* ========== Question Card ========== */
.question-card {
    position: relative;
    z-index: 0;
    background: #fff;
    border-radius: 8px;
    margin-bottom: 16px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
    overflow: hidden;
    transition: box-shadow 0.3s, transform 0.2s;
    border: 1px solid #ebeef5;
}

.question-card:hover {
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.1);
    transform: translateY(-1px);
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 16px;
    background: linear-gradient(135deg, #f5f7fa 0%, #e8ecf0 100%);
    border-bottom: 1px solid #ebeef5;
}

.card-tags {
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
}

.tag {
    padding: 2px 10px;
    border-radius: 10px;
    font-size: 11px;
    font-weight: 500;
}

.tag-grade {
    background: #ecf5ff;
    color: #409eff;
    border: 1px solid #d9ecff;
}

.tag-difficulty {
    border: 1px solid;
}

.tag-easy {
    background: #f0f9eb;
    color: #67c23a;
    border-color: #e1f3d8;
}

.tag-medium {
    background: #fdf6ec;
    color: #e6a23c;
    border-color: #faecd8;
}

.tag-hard {
    background: #fef0f0;
    color: #f56c6c;
    border-color: #fde2e2;
}

.tag-type {
    background: #f4f4f5;
    color: #909399;
    border-color: #e9e9eb;
}

.tag-knowledge {
    background: #fdfaff;
    color: #9c36cc;
    border-color: #f0d6f5;
}

.card-meta {
    display: flex;
    gap: 12px;
    font-size: 11px;
    color: #909399;
    align-items: center;
}
.copy-source-btn {
    cursor: pointer;
    color: #909399;
    margin-left: auto;
    font-size: 11px;
    transition: color 0.2s;
    user-select: none;
}
.copy-source-btn:hover {
    color: #409eff;
}
.remark-tag {
    cursor: pointer;
    color: #b37feb;
    font-size: 11px;
    padding: 2px 8px;
    border: 1px solid #d3adf7;
    border-radius: 4px;
    background: #f9f0ff;
    transition: all 0.2s;
    user-select: none;
    white-space: nowrap;
    max-width: 180px;
    overflow: hidden;
    text-overflow: ellipsis;
}
.remark-tag:hover {
    background: #efdbff;
    border-color: #b37feb;
}
.remark-empty {
    color: #c0c4cc;
    font-style: normal;
}

.card-body {
    padding: 16px 20px;
}

.question-text {
    font-size: 15px;
    line-height: 1.8;
    color: #303133;
    margin-bottom: 16px;
}

.question-text .latex-block {
    margin: 12px 0;
    padding: 8px 0;
    overflow-x: auto;
}

.options-list {
    list-style: none;
    margin: 10px 0 12px 0;
    padding: 0;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 8px 16px;
}

.options-list li {
    padding: 10px 14px;
    margin: 0;
    border-radius: 6px;
    border: 1px solid #ebeef5;
    font-size: 14px;
    line-height: 1.6;
    transition: background 0.2s;
}

.options-list li:hover {
    background: #f5f7fa;
}

.options-list li .option-label {
    font-weight: 600;
    margin-right: 6px;
    color: #409eff;
    min-width: 18px;
    display: inline-block;
}
.solution-section {
    border-top: 1px dashed #e4e7ed;
    padding-top: 12px;
    margin-top: 12px;
}

.solution-toggle {
    cursor: pointer;
    color: #409eff;
    font-size: 13px;
    display: flex;
    align-items: center;
    gap: 4px;
    user-select: none;
}

.solution-toggle:hover {
    color: #66b1ff;
}

.solution-content {
    display: none;
    margin-top: 10px;
    padding: 12px 16px;
    background: #fafafa;
    border-radius: 4px;
    font-size: 14px;
    line-height: 1.8;
    color: #606266;
}

.solution-content.show {
    display: block;
}

.solution-content .katex-display {
    margin: 8px 0;
}

/* ========== Empty State ========== */
.empty-state {
    text-align: center;
    padding: 60px 20px;
    color: #909399;
}

.empty-state .empty-icon {
    font-size: 48px;
    margin-bottom: 16px;
}

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

/* ========== Responsive ========== */
@media (max-width: 1200px) {
    .sidebar {
        width: 180px;
        min-width: 180px;
    }
    .knowledge-panel {
        width: 200px;
        min-width: 200px;
    }
}

/* KaTeX overrides */
.katex {
    font-size: 1.05em;
}

.katex-display {
    margin: 10px 0;
    overflow-x: auto;
    overflow-y: hidden;
    padding: 4px 0;
}

/* ========== Pagination ========== */
.pagination-nav {
    display: none;
    align-items: center;
    justify-content: center;
    gap: 6px;
    padding: 14px 0 8px;
    flex-wrap: wrap;
}

.page-btn {
    min-width: 36px;
    height: 32px;
    padding: 0 8px;
    border: 1px solid #dcdfe6;
    border-radius: 4px;
    background: #fff;
    color: #606266;
    font-size: 13px;
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
}

.page-btn:hover:not(:disabled):not(.active) {
    color: #409eff;
    border-color: #409eff;
}

.page-btn.active {
    background: #409eff;
    color: #fff;
    border-color: #409eff;
}

.page-btn.disabled {
    cursor: not-allowed;
    color: #c0c4cc;
    background: #f5f7fa;
}

.page-ellipsis {
    padding: 0 6px;
    color: #c0c4cc;
    font-size: 13px;
}

.page-info {
    font-size: 13px;
    color: #606266;
    padding: 0 8px;
    min-width: 100px;
    text-align: center;
}

.go-page-wrapper {
    display: flex;
    align-items: center;
    gap: 4px;
    margin-left: 8px;
    padding-left: 12px;
    border-left: 1px solid #e4e7ed;
}

.go-page-input {
    width: 52px;
    height: 32px;
    padding: 0 6px;
    border: 1px solid #dcdfe6;
    border-radius: 4px;
    text-align: center;
    font-size: 13px;
    outline: none;
    transition: border-color 0.2s;
}

.go-page-input:focus {
    border-color: #409eff;
}

.go-page-btn {
    height: 32px;
    padding: 0 12px;
    border: 1px solid #409eff;
    border-radius: 4px;
    background: #409eff;
    color: #fff;
    font-size: 13px;
    cursor: pointer;
    transition: all 0.2s;
}

.go-page-btn:hover {
    background: #66b1ff;
    border-color: #66b1ff;
}

/* ========== Paper Config ========== */
.paper-config {
    background: #fff;
    border-radius: 8px;
    padding: 16px;
    margin-bottom: 16px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
}

.btn-generate {
    padding: 8px 20px;
    background: linear-gradient(135deg, #409eff, #66b1ff);
    color: #fff;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 14px;
    transition: all 0.3s;
}

.btn-generate:hover {
    background: linear-gradient(135deg, #66b1ff, #409eff);
    box-shadow: 0 2px 8px rgba(64, 158, 255, 0.3);
}

.btn-print {
    padding: 8px 20px;
    background: linear-gradient(135deg, #67c23a, #85ce61);
    color: #fff;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 14px;
    transition: all 0.3s;
}

.btn-print:hover {
    background: linear-gradient(135deg, #85ce61, #67c23a);
    box-shadow: 0 2px 8px rgba(103, 194, 58, 0.3);
}

.paper-info {
    padding: 10px 16px;
    background: #ecf5ff;
    border-radius: 6px;
    margin-bottom: 12px;
    font-size: 14px;
    color: #409eff;
}

.paper-question {
    padding: 14px 18px;
    margin-bottom: 10px;
    background: #fff;
    border-radius: 8px;
    border-left: 3px solid #409eff;
    box-shadow: 0 1px 4px rgba(0, 0, 0, 0.06);
    transition: box-shadow 0.2s;
}

.paper-question:hover {
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.paper-q-num {
    font-weight: 700;
    color: #409eff;
    white-space: nowrap;
    display: inline-block;
    min-width: 30px;
}

.paper-q-body {
    display: block;
    margin-left: 10px;
}

.paper-q-text {
    line-height: 1.7;
    color: #303133;
    font-size: 15px;
    margin-bottom: 6px;
}

.paper-options {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 8px 20px;
    margin: 10px 0 8px 0;
    padding: 8px 12px;
    background: #fff;
    border-radius: 4px;
}

.paper-option {
    padding: 4px 0;
    font-size: 14px;
    line-height: 1.6;
}

.paper-answer {
    margin-top: 10px;
    padding: 8px 12px;
    background: #f0f9eb;
    border-radius: 4px;
    border-left: 3px solid #67c23a;
    font-size: 14px;
    color: #303133;
}

.paper-solution {
    margin-top: 10px;
    padding: 10px 14px;
    background: #f5f7fa;
    border-radius: 4px;
    border-left: 3px solid #409eff;
    font-size: 14px;
    color: #606266;
    line-height: 1.8;
}

.paper-meta {
    margin-top: 6px;
    font-size: 12px;
}

.paper-diff-tag {
    font-size: 12px;
    padding: 2px 8px;
    border-radius: 3px;
    display: inline-block;
}

/* ========== Materials ========== */
.material-card {
    background: #fff;
    border-radius: 8px;
    padding: 20px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
    border: 1px solid #ebeef5;
}

.formula-list p {
    margin-bottom: 8px;
    line-height: 1.8;
    color: #606266;
}

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

.tip-list li {
    padding: 10px 14px;
    margin-bottom: 8px;
    background: #f5f7fa;
    border-radius: 6px;
    line-height: 1.6;
    color: #606266;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(100px, 1fr));
    gap: 12px;
}

.stat-item {
    text-align: center;
    padding: 16px;
    background: linear-gradient(135deg, #f5f7fa, #e8ecf0);
    border-radius: 8px;
}

.stat-number {
    font-size: 28px;
    font-weight: 700;
    color: #409eff;
}

.stat-label {
    font-size: 12px;
    color: #909399;
    margin-top: 4px;
}

/* ========== Question Entry Form ========== */
.entry-form form {
    background: #fff;
    border-radius: 8px;
    padding: 20px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.06);
}

.form-row {
    display: flex;
    gap: 16px;
    margin-bottom: 12px;
    flex-wrap: wrap;
}

.form-group {
    flex: 1;
    min-width: 200px;
    margin-bottom: 12px;
}

.form-group label {
    display: block;
    font-size: 13px;
    font-weight: 500;
    color: #606266;
    margin-bottom: 6px;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 8px 12px;
    border: 1px solid #dcdfe6;
    border-radius: 6px;
    font-size: 14px;
    color: #303133;
    background: #fff;
    transition: border-color 0.3s;
    outline: none;
    font-family: inherit;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    border-color: #409eff;
    box-shadow: 0 0 0 2px rgba(64, 158, 255, 0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 60px;
}

.form-actions {
    display: flex;
    gap: 12px;
    margin-top: 16px;
}

.btn-submit {
    padding: 10px 24px;
    background: linear-gradient(135deg, #67c23a, #85ce61);
    color: #fff;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 14px;
    font-weight: 500;
    transition: all 0.3s;
}

.btn-submit:hover {
    background: linear-gradient(135deg, #85ce61, #67c23a);
    box-shadow: 0 2px 8px rgba(103, 194, 58, 0.3);
}

.btn-reset {
    padding: 10px 24px;
    background: #f5f7fa;
    color: #909399;
    border: 1px solid #dcdfe6;
    border-radius: 6px;
    cursor: pointer;
    font-size: 14px;
    transition: all 0.3s;
}

.btn-reset:hover {
    background: #ebeef5;
    color: #606266;
}

.added-question-item {
    background: #f0f9eb;
    border: 1px solid #e1f3d8;
    border-radius: 6px;
    padding: 12px 16px;
    margin-bottom: 8px;
    font-size: 14px;
    color: #67c23a;
}

/* ========== Parsed Preview Cards (录题中心) ========== */
.parsed-question-card {
    position: relative;
    z-index: 0;
    background: #fff;
    border-radius: 10px;
    margin-bottom: 16px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.06);
    border: 1px solid #ebeef5;
    overflow: hidden;
    transition: box-shadow 0.3s, transform 0.2s;
}

.parsed-question-card:hover {
    box-shadow: 0 4px 16px rgba(0,0,0,0.1);
    transform: translateY(-1px);
}

.parsed-q-header {
    padding: 10px 16px;
    font-weight: 600;
    font-size: 14px;
    color: #303133;
    background: linear-gradient(135deg, #f0f9eb, #e1f3d8);
    border-bottom: 1px solid #e1f3d8;
    display: flex;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
}

.parsed-q-type {
    font-weight: 400;
}

.parsed-q-meta-info {
    padding: 4px 16px 0;
    font-size: 12px;
    color: #909399;
    font-style: italic;
}

.parsed-q-body {
    padding: 10px 16px 14px;
    background: #fafafa;
}

.parsed-q-answer {
    margin: 8px 16px 6px;
    padding: 8px 12px;
    background: #f0f9eb;
    border-radius: 6px;
    border-left: 3px solid #67c23a;
    font-size: 14px;
}

.parsed-q-answer strong {
    color: #303133;
}

.parsed-q-solution {
    margin: 6px 16px 10px;
    padding: 10px 14px;
    background: #f0f5ff;
    border-radius: 6px;
    border-left: 3px solid #409eff;
    font-size: 14px;
    color: #606266;
    line-height: 1.8;
}

.parsed-q-solution strong {
    color: #303133;
}

.parsed-sol-content {
    margin-top: 4px;
}

.parsed-q-meta .form-row {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

.parsed-q-meta .form-group {
    flex: 1;
    min-width: 120px;
}

.parsed-q-meta .form-group label {
    display: block;
    font-size: 12px;
    font-weight: 500;
    color: #909399;
    margin-bottom: 4px;
}

.parsed-q-meta .form-group input,
.parsed-q-meta .form-group select {
    width: 100%;
    padding: 5px 8px;
    border: 1px solid #dcdfe6;
    border-radius: 4px;
    font-size: 13px;
    color: #303133;
    background: #fff;
    outline: none;
    transition: border-color 0.3s;
    box-sizing: border-box;
}

.parsed-q-meta .form-group input:focus,
.parsed-q-meta .form-group select:focus {
    border-color: #409eff;
    box-shadow: 0 0 0 2px rgba(64,158,255,0.1);
}

/* ========== Knowledge Search Widget ========== */
.knowledge-search-wrapper {
    display: flex;
    flex-direction: column;
    gap: 4px;
}
.knowledge-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 4px;
}
.knowledge-tag {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 2px 8px;
    background: #ecf5ff;
    color: #409eff;
    border: 1px solid #d9ecff;
    border-radius: 4px;
    font-size: 11px;
    line-height: 1.6;
}
.knowledge-tag .remove-tag {
    cursor: pointer;
    font-size: 14px;
    font-weight: bold;
    color: #a8abb2;
    line-height: 1;
}
.knowledge-tag .remove-tag:hover {
    color: #f56c6c;
}
.knowledge-input-wrapper {
    position: relative;
}
.knowledge-search-input {
    width: 100%;
    padding: 4px 8px;
    border: 1px solid #dcdfe6;
    border-radius: 4px;
    font-size: 12px;
    outline: none;
    box-sizing: border-box;
}
.knowledge-search-input:focus {
    border-color: #409eff;
}
.knowledge-dropdown {
    position: absolute;
    bottom: 100%;
    left: 0;
    right: 0;
    background: #fff;
    border: 1px solid #e4e7ed;
    border-radius: 4px;
    box-shadow: 0 2px 12px rgba(0,0,0,0.1);
    max-height: 200px;
    overflow-y: auto;
    z-index: 100;
    margin-bottom: 2px;
}
.knowledge-dropdown-item {
    padding: 6px 10px;
    font-size: 12px;
    cursor: pointer;
    color: #606266;
}
.knowledge-dropdown-item:hover {
    background: #ecf5ff;
    color: #409eff;
}
/* ========== Enumerate (有序列表) ========== */
.parsed-enum {
    padding-left: 2em;
    margin: 6px 0;
    list-style: none;
    counter-reset: enum-l1;
}
.parsed-enum > li {
    counter-increment: enum-l1;
    margin-bottom: 4px;
    line-height: 1.7;
    position: relative;
}
.parsed-enum > li::before {
    content: counter(enum-l1) ".\00a0";
    position: absolute;
    left: -2em;
    width: 2em;
    text-align: right;
}
.parsed-enum .parsed-enum {
    counter-reset: enum-l2;
}
.parsed-enum .parsed-enum > li {
    counter-increment: enum-l2;
}
.parsed-enum .parsed-enum > li::before {
    content: "(" counter(enum-l2) ")\00a0";
}
.parsed-enum .parsed-enum .parsed-enum {
    counter-reset: enum-l3;
}
.parsed-enum .parsed-enum .parsed-enum > li::before {
    content: counter(enum-l3, lower-roman) ".\00a0";
}

.latex-table {
    border-collapse: collapse;
    margin: 12px 0;
    width: 100%;
    font-size: 14px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
    border-radius: 4px;
    overflow: hidden;
}
.latex-table th,
.latex-table td {
    border: 1px solid #dcdfe6;
    padding: 8px 14px;
    text-align: center;
    font-size: 14px;
}
.latex-table th {
    background: #f5f7fa;
    color: #303133;
    font-weight: 600;
    border-bottom: 2px solid #c0c4cc;
}
.latex-table td {
    background: #fff;
}
.latex-table tr:hover td {
    background: #f5f7fa;
}
.latex-table tbody tr:last-child td {
    border-bottom: 2px solid #dcdfe6;
}
.latex-table tbody tr:first-child td {
    border-top: 2px solid #dcdfe6;
}
.btn-add-to-bank {
    background: linear-gradient(135deg, #409eff, #66b1ff) !important;
}

.btn-add-to-bank:hover:not(:disabled) {
    background: linear-gradient(135deg, #66b1ff, #409eff) !important;
    box-shadow: 0 2px 8px rgba(64,158,255,0.3);
}

/* ========== TikZ Rendering ========== */
.tikz-images {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    justify-content: flex-end;
    align-items: flex-end;
    padding: 8px 16px 16px;
    width: 100%;
    box-sizing: border-box;
    min-height: 48px;
}
.tikz-images svg {
    max-width: 400px;
    max-height: 250px;
    height: auto;
    display: block;
    cursor: grab;
}
.tikz-images svg.tikz-dragging {
    cursor: grabbing;
    z-index: 10;
    filter: drop-shadow(0 2px 8px rgba(0,0,0,0.15));
}
.tikz-code-block { display: none; }
.tikz-images iframe {
    background: transparent;
    border: none;
    border-radius: 4px;
}

/* ========== Paper Maker New ========== */
.paper-section {
    margin-bottom: 14px;
    padding-bottom: 14px;
    border-bottom: 1px solid #ebeef5;
}
.paper-section:last-of-type {
    border-bottom: none;
}
.paper-section-title {
    font-size: 13px;
    font-weight: 600;
    color: #606266;
    margin-bottom: 10px;
}
.paper-type-row {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}
.paper-type-row label {
    font-size: 13px;
    color: #606266;
    display: flex;
    align-items: center;
    gap: 6px;
}
.paper-type-input {
    width: 56px;
    padding: 4px 6px;
    border: 1px solid #dcdfe6;
    border-radius: 4px;
    font-size: 13px;
    text-align: center;
    outline: none;
}
.paper-type-input:focus {
    border-color: #409eff;
}

/* Paper maker knowledge point search */
.paper-kp-search-wrapper {
    display: flex;
    flex-direction: column;
    gap: 6px;
}
.paper-kp-tags {
    display: flex;
    flex-direction: column;
    gap: 6px;
}
.paper-kp-tag {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 6px 10px;
    background: #f5f7fa;
    border: 1px solid #e4e7ed;
    border-radius: 6px;
    font-size: 13px;
    color: #303133;
    flex-wrap: wrap;
}
.paper-kp-tag .kp-name {
    font-weight: 600;
    color: #409eff;
    min-width: 80px;
    flex-shrink: 0;
}
.paper-kp-tag .kp-counts {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    flex: 1;
}
.paper-kp-tag .kp-counts label {
    font-size: 12px;
    color: #606266;
    display: flex;
    align-items: center;
    gap: 3px;
}
.paper-kp-tag .kp-counts input {
    width: 44px;
    padding: 2px 4px;
    border: 1px solid #dcdfe6;
    border-radius: 3px;
    font-size: 12px;
    text-align: center;
    outline: none;
}
.paper-kp-tag .kp-counts input:focus {
    border-color: #409eff;
}
.paper-kp-tag .kp-remove {
    cursor: pointer;
    color: #c0c4cc;
    font-size: 16px;
    line-height: 1;
    padding: 0 2px;
    flex-shrink: 0;
}
.paper-kp-tag .kp-remove:hover {
    color: #f56c6c;
}
.paper-kp-input-wrapper {
    position: relative;
}
.paper-kp-search-input {
    width: 100%;
    padding: 6px 10px;
    border: 1px solid #dcdfe6;
    border-radius: 4px;
    font-size: 13px;
    outline: none;
    box-sizing: border-box;
}
.paper-kp-search-input:focus {
    border-color: #409eff;
}
.paper-kp-dropdown {
    position: absolute;
    bottom: 100%;
    left: 0;
    right: 0;
    background: #fff;
    border: 1px solid #e4e7ed;
    border-radius: 4px;
    box-shadow: 0 2px 12px rgba(0,0,0,0.1);
    max-height: 200px;
    overflow-y: auto;
    z-index: 100;
    margin-bottom: 2px;
}
.paper-kp-dropdown-item {
    padding: 6px 10px;
    font-size: 12px;
    cursor: pointer;
    color: #606266;
}
.paper-kp-dropdown-item:hover {
    background: #ecf5ff;
    color: #409eff;
}

/* ========== Edit Modal ========== */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.4);
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
}
.modal-box {
    background: #fff;
    border-radius: 8px;
    width: 700px;
    max-width: 90vw;
    max-height: 85vh;
    display: flex;
    flex-direction: column;
    box-shadow: 0 8px 24px rgba(0,0,0,0.15);
}
.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 14px 20px;
    font-size: 16px;
    font-weight: 600;
    border-bottom: 1px solid #e4e7ed;
}
.modal-close {
    cursor: pointer;
    font-size: 22px;
    color: #909399;
    line-height: 1;
}
.modal-close:hover { color: #333; }
.modal-body {
    flex: 1;
    padding: 16px 20px;
    overflow-y: auto;
    min-height: 200px;
}
.edit-source-textarea {
    width: 100%;
    min-height: 300px;
    padding: 10px;
    border: 1px solid #dcdfe6;
    border-radius: 4px;
    font-family: 'Consolas', 'Courier New', monospace;
    font-size: 13px;
    line-height: 1.5;
    resize: vertical;
    tab-size: 2;
}
.edit-source-textarea:focus {
    outline: none;
    border-color: #409eff;
    box-shadow: 0 0 0 2px rgba(64,158,255,0.2);
}
.modal-footer {
    display: flex;
    justify-content: flex-end;
    gap: 10px;
    padding: 12px 20px;
    border-top: 1px solid #e4e7ed;
}
.modal-footer .btn { padding: 8px 20px; border-radius: 4px; font-size: 14px; cursor: pointer; border: none; }
.btn-primary { background: #409eff; color: #fff; }
.btn-primary:hover { background: #66b1ff; }
.btn-danger { background: #f56c6c; color: #fff; }
.btn-danger:hover { background: #f78989; }
.btn-replace { background: #e6a23c; color: #fff; }
.btn-replace:hover { background: #ebb563; }

/* ========== Card Footer ========== */
.card-footer {
    display: flex;
    justify-content: flex-end;
    padding: 8px 16px 12px;
    border-top: 1px solid #ebeef5;
}
.btn-edit {
    padding: 4px 12px;
    font-size: 13px;
    border: 1px solid #dcdfe6;
    border-radius: 4px;
    background: #fff;
    color: #606266;
    cursor: pointer;
}
.btn-edit:hover {
    border-color: #409eff;
    color: #409eff;
}

/* ========== CSS Icons (replacing emoji) ========== */
.icon {
    display: inline-block;
    width: 1em;
    height: 1em;
    vertical-align: -0.125em;
    flex-shrink: 0;
    position: relative;
}
.icon::before,
.icon::after,
.icon [class*="icon-"]::before,
.icon [class*="icon-"]::after {
    box-sizing: border-box;
}
.icon-lg {
    width: 1.4em;
    height: 1.4em;
    vertical-align: -0.2em;
    position: relative;
}
.icon-xl {
    width: 2em;
    height: 2em;
    vertical-align: -0.3em;
    position: relative;
}
.icon-xxl {
    width: 2.8em;
    height: 2.8em;
    vertical-align: -0.35em;
    position: relative;
}

/* Book */
.icon-book::before {
    content: '';
    position: absolute;
    left: 15%; top: 10%;
    width: 70%; height: 80%;
    border: 2px solid currentColor;
    border-radius: 2px 6px 6px 2px;
    background: linear-gradient(90deg, transparent 45%, currentColor 45%, currentColor 48%, transparent 48%);
}

/* Pen */
.icon-pen::before {
    content: '';
    position: absolute;
    left: 30%; top: 15%;
    width: 3px; height: 70%;
    background: currentColor;
    transform: rotate(-30deg);
    border-radius: 1px;
}
.icon-pen::after {
    content: '';
    position: absolute;
    left: 18%; top: 68%;
    border: 6px solid transparent;
    border-bottom-color: currentColor;
    transform: rotate(-30deg);
}

/* Clipboard / List */
.icon-clipboard::before {
    content: '';
    position: absolute;
    left: 20%; top: 10%;
    width: 60%; height: 80%;
    border: 2px solid currentColor;
    border-radius: 3px;
}
.icon-clipboard::after {
    content: '';
    position: absolute;
    left: 30%; top: 30%;
    width: 40%; height: 2px;
    background: currentColor;
    box-shadow: 0 6px 0 currentColor, 0 12px 0 currentColor;
}

/* Plus */
.icon-plus::before,
.icon-plus::after {
    content: '';
    position: absolute;
    background: currentColor;
    border-radius: 1px;
}
.icon-plus::before {
    left: 20%; top: 45%;
    width: 60%; height: 10%;
}
.icon-plus::after {
    left: 45%; top: 20%;
    width: 10%; height: 60%;
}

/* Upload */
.icon-upload::before {
    content: '';
    position: absolute;
    left: 20%; top: 55%;
    width: 60%; height: 35%;
    border: 2px solid currentColor;
    border-radius: 2px 2px 0 0;
    border-bottom: none;
    background: transparent;
}
.icon-upload::after {
    content: '';
    position: absolute;
    left: 45%; top: 20%;
    width: 10%; height: 40%;
    background: currentColor;
    box-shadow: -5px 5px 0 -2px currentColor, 5px 5px 0 -2px currentColor;
    border-radius: 1px;
}

/* Download */
.icon-download::before {
    content: '';
    position: absolute;
    left: 20%; top: 10%;
    width: 60%; height: 35%;
    border: 2px solid currentColor;
    border-radius: 2px 2px 0 0;
    border-bottom: none;
    background: transparent;
}
.icon-download::after {
    content: '';
    position: absolute;
    left: 45%; top: 38%;
    width: 10%; height: 40%;
    background: currentColor;
    border-radius: 1px;
    box-shadow: -5px -5px 0 -2px currentColor, 5px -5px 0 -2px currentColor;
}

/* Trash */
.icon-trash::before {
    content: '';
    position: absolute;
    left: 25%; top: 30%;
    width: 50%; height: 60%;
    border: 2px solid currentColor;
    border-radius: 0 0 3px 3px;
    border-top: none;
    background: transparent;
}
.icon-trash::after {
    content: '';
    position: absolute;
    left: 30%; top: 10%;
    width: 40%; height: 22%;
    border: 2px solid currentColor;
    border-bottom: none;
    border-radius: 3px 3px 0 0;
    background: transparent;
}

/* Triangle / Ruler */
.icon-triangle::before {
    content: '';
    position: absolute;
    left: 10%; top: 10%;
    width: 80%; height: 80%;
    border: 2px solid currentColor;
    border-right: none;
    border-bottom: none;
    transform: rotate(-45deg);
    border-radius: 2px 0 0 0;
}
.icon-triangle::after {
    content: '';
    position: absolute;
    left: 15%; bottom: 18%;
    width: 35%; height: 2px;
    background: currentColor;
    box-shadow: 0 5px 0 currentColor, 0 10px 0 currentColor;
    transform: rotate(-45deg);
    transform-origin: left center;
}

/* Wave */
.icon-wave::before {
    content: '';
    position: absolute;
    left: 10%; top: 40%;
    width: 80%; height: 20%;
    border-radius: 0 0 50% 50% / 0 0 100% 100%;
    border: 2px solid currentColor;
    border-top: none;
    background: transparent;
}
.icon-wave::after {
    content: '';
    position: absolute;
    left: 10%; top: 40%;
    width: 80%; height: 20%;
    border-radius: 50% 50% 0 0 / 100% 100% 0 0;
    border: 2px solid currentColor;
    border-bottom: none;
    background: transparent;
}

/* Spiral */
.icon-spiral::before {
    content: '';
    position: absolute;
    left: 10%; top: 10%;
    width: 80%; height: 80%;
    border: 2px solid currentColor;
    border-radius: 50%;
    background: conic-gradient(from 0deg, transparent 0deg 270deg, currentColor 270deg 360deg);
    mask: radial-gradient(circle, transparent 40%, #000 40%);
    -webkit-mask: radial-gradient(circle, transparent 40%, #000 40%);
}

/* Chart Up */
.icon-chart-up::before {
    content: '';
    position: absolute;
    left: 15%; bottom: 20%;
    width: 70%; height: 60%;
    border-left: 2px solid currentColor;
    border-bottom: 2px solid currentColor;
}
.icon-chart-up::after {
    content: '';
    position: absolute;
    left: 22%; bottom: 20%;
    width: 4px; height: 50%;
    background: currentColor;
    border-radius: 1px;
    box-shadow: 12px -10px 0 currentColor, 24px 10px 0 currentColor, 36px -20px 0 currentColor;
}

/* Right Arrow (also used for next page) */
.icon-arrow::before {
    content: '';
    position: absolute;
    left: 25%; top: 45%;
    width: 50%; height: 10%;
    background: currentColor;
    border-radius: 1px;
}
.icon-arrow::after {
    content: '';
    position: absolute;
    left: 50%; top: 25%;
    border: 10px solid transparent;
    border-left-color: currentColor;
    border-right: none;
}

/* Left Arrow */
.icon-arrow-left::before {
    content: '';
    position: absolute;
    left: 25%; top: 45%;
    width: 50%; height: 10%;
    background: currentColor;
    border-radius: 1px;
}
.icon-arrow-left::after {
    content: '';
    position: absolute;
    left: 30%; top: 25%;
    border: 10px solid transparent;
    border-right-color: currentColor;
    border-left: none;
}

/* Double Right Arrow (last) */
.icon-arrow-double-right::before {
    content: '';
    position: absolute;
    left: 15%; top: 45%;
    width: 50%; height: 10%;
    background: currentColor;
    border-radius: 1px;
    box-shadow: 16px 0 0 currentColor;
}
.icon-arrow-double-right::after {
    content: '';
    position: absolute;
    left: 35%; top: 25%;
    border: 10px solid transparent;
    border-left-color: currentColor;
    border-right: none;
    box-shadow: 16px 0 0 0 currentColor, 20px 0 0 0 transparent;
}

/* Double Left Arrow (first) */
.icon-arrow-double-left::before {
    content: '';
    position: absolute;
    left: 15%; top: 45%;
    width: 50%; height: 10%;
    background: currentColor;
    border-radius: 1px;
}
.icon-arrow-double-left::after {
    content: '';
    position: absolute;
    left: 15%; top: 25%;
    border: 10px solid transparent;
    border-right-color: currentColor;
    border-left: none;
    box-shadow: 16px 0 0 0 currentColor, 20px 0 0 0 transparent;
}

/* Number 123 */
.icon-number::before {
    content: '123';
    position: absolute;
    font-size: 0.7em;
    font-weight: 700;
    font-family: serif;
    left: 10%; top: 10%;
    width: 80%; height: 80%;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 2px solid currentColor;
    border-radius: 3px;
    color: currentColor;
}

/* Circle (空圆) */
.icon-circle::before {
    content: '';
    position: absolute;
    left: 10%; top: 10%;
    width: 80%; height: 80%;
    border: 2px solid currentColor;
    border-radius: 50%;
}

/* 3D Cube */
.icon-cube::before {
    content: '';
    position: absolute;
    left: 15%; top: 25%;
    width: 70%; height: 50%;
    border: 2px solid currentColor;
    background: transparent;
}
.icon-cube::after {
    content: '';
    position: absolute;
    left: 25%; top: 5%;
    width: 70%; height: 50%;
    border: 2px solid currentColor;
    background: transparent;
    border-bottom: none;
}

/* Balance Scale - simplified */
.icon-balance::before {
    content: '';
    position: absolute;
    left: 10%; top: 35%;
    width: 80%; height: 2px;
    background: currentColor;
    box-shadow: 0 28px 0 currentColor;
}
.icon-balance::after {
    content: '';
    position: absolute;
    left: 46%; top: 35%;
    width: 8%; height: 50%;
    background: currentColor;
    border-radius: 2px;
    box-shadow: -20px 10px 0 -4px currentColor, 20px 10px 0 -4px currentColor;
}

/* Bar Chart */
.icon-bar-chart::before {
    content: '';
    position: absolute;
    left: 15%; bottom: 20%;
    width: 70%; height: 60%;
    border-left: 2px solid currentColor;
    border-bottom: 2px solid currentColor;
}
.icon-bar-chart::after {
    content: '';
    position: absolute;
    left: 22%; bottom: 20%;
    width: 10%; height: 50%;
    background: currentColor;
    border-radius: 1px 1px 0 0;
    box-shadow: 16px -10px 0 currentColor, 32px -30px 0 currentColor;
}

/* Package Box */
.icon-box::before {
    content: '';
    position: absolute;
    left: 15%; top: 25%;
    width: 70%; height: 60%;
    border: 2px solid currentColor;
    border-radius: 2px;
}
.icon-box::after {
    content: '';
    position: absolute;
    left: 15%; top: 25%;
    width: 35%; height: 35%;
    border: 2px solid currentColor;
    border-top: none;
    border-left: none;
    border-radius: 0 4px 0 0;
}

/* Folder */
.icon-folder::before {
    content: '';
    position: absolute;
    left: 10%; top: 30%;
    width: 80%; height: 55%;
    border: 2px solid currentColor;
    border-radius: 0 4px 4px 4px;
    border-top: none;
}
.icon-folder::after {
    content: '';
    position: absolute;
    left: 10%; top: 22%;
    width: 35%; height: 12%;
    border: 2px solid currentColor;
    border-bottom: none;
    border-radius: 4px 4px 0 0;
}

/* Search / Magnifying Glass */
.icon-search::before {
    content: '';
    position: absolute;
    left: 15%; top: 15%;
    width: 45%; height: 45%;
    border: 2px solid currentColor;
    border-radius: 50%;
}
.icon-search::after {
    content: '';
    position: absolute;
    left: 50%; top: 50%;
    width: 3px; height: 30%;
    background: currentColor;
    transform: rotate(-45deg);
    transform-origin: top left;
    border-radius: 1px;
}

/* Dice */
.icon-dice::before {
    content: '';
    position: absolute;
    left: 15%; top: 15%;
    width: 70%; height: 70%;
    border: 2px solid currentColor;
    border-radius: 4px;
}
.icon-dice::after {
    content: '';
    position: absolute;
    left: 30%; top: 30%;
    width: 6px; height: 6px;
    background: currentColor;
    border-radius: 50%;
    box-shadow: 20px 0 0 currentColor, 0 20px 0 currentColor, 20px 20px 0 currentColor,
                10px 10px 0 currentColor;
}

/* Printer */
.icon-printer::before {
    content: '';
    position: absolute;
    left: 15%; top: 25%;
    width: 70%; height: 45%;
    border: 2px solid currentColor;
    border-radius: 2px;
    background: transparent;
}
.icon-printer::after {
    content: '';
    position: absolute;
    left: 25%; top: 55%;
    width: 50%; height: 35%;
    border: 2px solid currentColor;
    border-top: none;
    background: transparent;
}

/* Lightbulb */
.icon-bulb::before {
    content: '';
    position: absolute;
    left: 22%; top: 8%;
    width: 56%; height: 60%;
    border: 2px solid currentColor;
    border-radius: 50% 50% 40% 40%;
}
.icon-bulb::after {
    content: '';
    position: absolute;
    left: 40%; top: 65%;
    width: 20%; height: 20%;
    border: 2px solid currentColor;
    border-top: none;
    border-radius: 0 0 2px 2px;
}

/* Calendar */
.icon-calendar::before {
    content: '';
    position: absolute;
    left: 10%; top: 20%;
    width: 80%; height: 70%;
    border: 2px solid currentColor;
    border-radius: 3px;
    background: transparent;
}
.icon-calendar::after {
    content: '';
    position: absolute;
    left: 10%; top: 40%;
    width: 80%; height: 2px;
    background: currentColor;
    box-shadow: 0 -10px 0 currentColor;
}

/* Checkmark */
.icon-check::before {
    content: '';
    position: absolute;
    left: 15%; top: 40%;
    width: 25%; height: 35%;
    border: 3px solid currentColor;
    border-top: none;
    border-right: none;
    transform: rotate(-45deg);
}

/* Warning */
.icon-warning::before {
    content: '!';
    position: absolute;
    left: 15%; top: 15%;
    width: 70%; height: 70%;
    border: 2px solid currentColor;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1em;
    font-weight: 700;
    color: currentColor;
    line-height: 1;
}

/* Document */
.icon-document::before {
    content: '';
    position: absolute;
    left: 20%; top: 10%;
    width: 55%; height: 80%;
    border: 2px solid currentColor;
    border-radius: 2px;
}
.icon-document::after {
    content: '';
    position: absolute;
    left: 30%; top: 30%;
    width: 35%; height: 2px;
    background: currentColor;
    box-shadow: 0 6px 0 currentColor, 0 12px 0 currentColor;
}

/* Scroll */
.icon-scroll::before {
    content: '';
    position: absolute;
    left: 25%; top: 10%;
    width: 50%; height: 80%;
    border: 2px solid currentColor;
    border-radius: 0 6px 6px 0;
}
.icon-scroll::after {
    content: '';
    position: absolute;
    left: 25%; top: 10%;
    width: 25%; height: 40%;
    border: 2px solid currentColor;
    border-right: none;
    border-radius: 4px 0 0 4px;
    background: transparent;
}

/* Cross / X */
.icon-cross::before,
.icon-cross::after {
    content: '';
    position: absolute;
    left: 48%; top: 15%;
    width: 4%; height: 70%;
    background: currentColor;
    border-radius: 1px;
}
.icon-cross::before { transform: rotate(45deg); }
.icon-cross::after { transform: rotate(-45deg); }

/* Small times (×) for remove buttons */
.icon-times::before,
.icon-times::after {
    content: '';
    position: absolute;
    left: 48%; top: 20%;
    width: 4%; height: 60%;
    background: currentColor;
    border-radius: 1px;
}
.icon-times::before { transform: rotate(45deg); }
.icon-times::after { transform: rotate(-45deg); }

/* Folder toggle arrow */
.icon-folder-toggle {
    display: inline-block;
    width: 0.6em;
    height: 0.6em;
    vertical-align: middle;
    position: relative;
}
.icon-folder-toggle::before {
    content: '';
    position: absolute;
    left: 20%; top: 40%;
    width: 60%; height: 15%;
    background: currentColor;
    border-radius: 1px;
}
.icon-folder-toggle::after {
    content: '';
    position: absolute;
    left: 40%; top: 18%;
    border: 6px solid transparent;
    border-left-color: currentColor;
    border-right: none;
}

/* Solution arrow (▶/▼) - reuse arrow + rotate */
.icon-solution-arrow {
    display: inline-block;
    width: 0.6em;
    height: 0.6em;
    transition: transform 0.2s;
    vertical-align: middle;
    position: relative;
}
.icon-solution-arrow::before {
    content: '';
    position: absolute;
    left: 20%; top: 40%;
    width: 60%; height: 15%;
    background: currentColor;
    border-radius: 1px;
}
.icon-solution-arrow::after {
    content: '';
    position: absolute;
    left: 40%; top: 18%;
    border: 7px solid transparent;
    border-left-color: currentColor;
    border-right: none;
}
.icon-solution-arrow.expanded {
    transform: rotate(90deg);
}

/* Filter arrow (▶) */
.icon-filter-arrow {
    display: inline-block;
    width: 0.6em;
    height: 0.6em;
    transition: transform 0.2s;
    color: #909399;
    position: relative;
}
.icon-filter-arrow::before {
    content: '';
    position: absolute;
    left: 20%; top: 40%;
    width: 60%; height: 15%;
    background: currentColor;
    border-radius: 1px;
}
.icon-filter-arrow::after {
    content: '';
    position: absolute;
    left: 40%; top: 18%;
    border: 7px solid transparent;
    border-left-color: currentColor;
    border-right: none;
}
.filter-bar.collapsed .icon-filter-arrow {
    transform: rotate(0deg);
}
.filter-bar:not(.collapsed) .icon-filter-arrow {
    transform: rotate(90deg);
}

/* Category arrow dropdown (▾) */
.category-title .icon-cat-arrow {
    display: inline-block;
    width: 0.6em;
    height: 0.6em;
    transition: transform 0.2s;
    flex-shrink: 0;
}
.category-title .icon-cat-arrow::before {
    content: '';
    position: absolute;
    left: 15%; top: 30%;
    width: 70%; height: 15%;
    background: currentColor;
    border-radius: 1px;
}
.category-title .icon-cat-arrow::after {
    content: '';
    position: absolute;
    left: 30%; top: 15%;
    border: 6px solid transparent;
    border-top-color: currentColor;
    border-bottom: none;
}
.category-title.collapsed .icon-cat-arrow {
    transform: rotate(-90deg);
}

/* Nav icons - bigger, centered */
.nav-icon .icon {
    width: 1.2em;
    height: 1.2em;
}