:root {
    --bg-color: #0f172a;
    --sidebar-bg: #1e293b;
    --surface-color: #1e293b;
    --surface-hover: #334155;
    --border-color: #334155;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --primary-color: #3b82f6;
    --primary-hover: #2563eb;
    --success-color: #10b981;
    --danger-color: #ef4444;
    --danger-hover: #dc2626;
    --radius-md: 12px;
    --radius-lg: 16px;
    --shadow-sm: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

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

body {
    font-family: 'Inter', 'Noto Sans TC', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    min-height: 100vh;
    line-height: 1.6;
    overflow-x: hidden;
}

noscript {
    display: block;
    padding: 1rem;
    background: rgba(239, 68, 68, 0.12);
    color: #fecaca;
    text-align: center;
}

/* Layout */
.app-layout {
    display: flex;
    height: 100vh;
}

.main-content {
    flex: 1;
    overflow-y: auto;
    padding: 2rem;
}

.content-container {
    max-width: 900px;
    margin: 0 auto;
}

/* Sidebar */
.sidebar {
    width: 320px;
    background-color: var(--sidebar-bg);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    height: 100%;
}

.mobile-sidebar-toggle,
.mobile-sidebar-backdrop {
    display: none;
}

.sidebar-header {
    padding: 1.5rem;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.sidebar-header h2 {
    font-size: 1.25rem;
    color: var(--text-primary);
}

.sidebar-actions {
    display: flex;
    gap: 0.5rem;
}

.icon-btn {
    background: transparent;
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
    padding: 0.4rem;
    border-radius: 8px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s;
}

.icon-btn:hover {
    color: var(--primary-color);
    border-color: var(--primary-color);
    background-color: rgba(59, 130, 246, 0.1);
}

.primary-btn-sm {
    background-color: rgba(59, 130, 246, 0.1);
    color: var(--primary-color);
    border: 1px solid rgba(59, 130, 246, 0.3);
    padding: 0.4rem 0.8rem;
    border-radius: 8px;
    font-size: 0.875rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
}

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

.history-list {
    flex: 1;
    overflow-y: auto;
    padding: 1rem;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.history-item {
    background-color: rgba(15, 23, 42, 0.4);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1rem;
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.history-item:hover,
.history-item.active {
    border-color: var(--primary-color);
    background-color: rgba(59, 130, 246, 0.05);
}

.history-item-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
}

.history-item-title {
    font-weight: 600;
    font-size: 0.95rem;
    word-break: break-all;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
    padding-right: 0.5rem;
}

.history-item-actions {
    display: flex;
    gap: 0.25rem;
    flex-shrink: 0;
}

.delete-btn,
.edit-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 4px;
    border-radius: 4px;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
}

.delete-btn:hover {
    color: var(--danger-color);
    background-color: rgba(239, 68, 68, 0.1);
}

.edit-btn:hover {
    color: var(--primary-color);
    background-color: rgba(59, 130, 246, 0.1);
}

.history-item-meta {
    font-size: 0.8rem;
    color: var(--text-secondary);
    display: flex;
    justify-content: space-between;
}

.history-item[draggable="true"] {
    cursor: grab;
}

.history-item[draggable="true"]:active {
    cursor: grabbing;
    opacity: 0.8;
    transform: scale(0.98);
}

/* Folder Styles */
.folder-group {
    border: 1px solid transparent;
    border-radius: var(--radius-md);
    margin-bottom: 0.5rem;
    transition: all 0.2s;
}

.folder-group.dragover {
    border-color: var(--primary-color);
    background-color: rgba(59, 130, 246, 0.05);
    box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.2);
}

.folder-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 1rem;
    cursor: pointer;
    border-radius: var(--radius-md);
    background-color: rgba(30, 41, 59, 0.8);
    transition: all 0.2s;
    font-weight: 600;
}

.folder-header:hover {
    background-color: var(--surface-hover);
}

.folder-header-left {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: #cbd5e1;
}

.folder-icon {
    color: #fbbf24;
}

.folder-content {
    padding: 0.5rem 0 0.5rem 1rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.folder-content.collapsed {
    display: none;
}

.root-dropzone {
    padding: 1rem;
    margin: 1rem;
    border: 2px dashed var(--border-color);
    border-radius: var(--radius-md);
    text-align: center;
    color: var(--text-secondary);
    transition: all 0.2s;
}

.root-dropzone.dragover {
    border-color: var(--primary-color);
    background-color: rgba(59, 130, 246, 0.1);
    color: var(--primary-color);
}

.uncategorized-label {
    font-size: 0.85rem;
    color: var(--text-secondary);
    padding: 0 0.5rem;
    margin-top: 1rem;
    margin-bottom: 0.25rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.5rem;
}

.uncategorized-import-btn {
    border: 1px solid rgba(59, 130, 246, 0.35);
    background: rgba(59, 130, 246, 0.1);
    color: #93c5fd;
    border-radius: 7px;
    cursor: pointer;
    font-size: 0.75rem;
    font-weight: 700;
    padding: 0.25rem 0.45rem;
    letter-spacing: 0;
}

.uncategorized-import-btn:hover {
    background: rgba(59, 130, 246, 0.18);
    color: #bfdbfe;
}

.empty-history {
    text-align: center;
    color: var(--text-secondary);
    padding: 2rem 1rem;
    font-size: 0.9rem;
}

/* Header */
.app-header {
    text-align: center;
    margin-bottom: 2rem;
}

.app-header h1 {
    font-size: 2.25rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    background: linear-gradient(135deg, #60a5fa, #a78bfa);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.app-header p {
    color: var(--text-secondary);
    font-size: 1rem;
}

/* Upload Zone */
.upload-zone {
    border: 2px dashed var(--border-color);
    border-radius: var(--radius-lg);
    background-color: var(--surface-color);
    padding: 4rem 2rem;
    text-align: center;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    cursor: pointer;
    position: relative;
    overflow: hidden;
}

.upload-zone:hover,
.upload-zone.dragover {
    border-color: var(--primary-color);
    background-color: var(--surface-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.upload-icon {
    width: 64px;
    height: 64px;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    transition: transform 0.3s ease;
}

.upload-zone:hover .upload-icon,
.upload-zone.dragover .upload-icon {
    transform: translateY(-5px);
}

.upload-zone h2 {
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
}

.file-types {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

.upload-btn {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 0.75rem 2rem;
    font-size: 1rem;
    font-weight: 500;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: background-color 0.2s;
}

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

/* Loading State */
.loading-zone {
    text-align: center;
    padding: 4rem 2rem;
    background-color: var(--surface-color);
    border-radius: var(--radius-lg);
}

.spinner {
    width: 50px;
    height: 50px;
    border: 4px solid var(--border-color);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    margin: 0 auto 1.5rem;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

/* Results Zone */
.results-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border-color);
}

.results-header>div {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.exam-title {
    font-size: 1.25rem;
    max-width: 400px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.badge {
    background-color: rgba(59, 130, 246, 0.2);
    color: #60a5fa;
    padding: 0.25rem 0.75rem;
    border-radius: 9999px;
    font-size: 0.9rem;
    font-weight: 600;
    white-space: nowrap;
}

.secondary-btn {
    background-color: transparent;
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    padding: 0.5rem 1rem;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all 0.2s;
}

.secondary-btn:hover {
    background-color: var(--surface-hover);
    border-color: var(--text-secondary);
}

.question-search-bar {
    margin: 0 0 1.5rem;
    display: flex;
    gap: 0.65rem;
}

.question-search-input {
    flex: 1;
    min-width: 0;
    background-color: rgba(15, 23, 42, 0.55);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font: inherit;
    padding: 0.75rem 1rem;
    transition: border-color 0.2s, box-shadow 0.2s, background-color 0.2s;
}

.question-search-input::placeholder {
    color: var(--text-secondary);
}

.question-search-input:focus {
    background-color: rgba(15, 23, 42, 0.75);
    border-color: var(--primary-color);
    outline: none;
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.18);
}

.question-search-btn {
    flex: 0 0 auto;
    background-color: var(--primary-color);
    border: 1px solid var(--primary-color);
    border-radius: var(--radius-md);
    color: #fff;
    cursor: pointer;
    font: inherit;
    font-weight: 700;
    padding: 0.75rem 1.15rem;
}

.question-search-btn:hover {
    background-color: var(--primary-hover);
    border-color: var(--primary-hover);
}

.search-highlight {
    background: #fef08a;
    color: #111827;
    border-radius: 4px;
    padding: 0 0.12em;
}

/* Question Cards */
.questions-container {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.question-card {
    background-color: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    transition: transform 0.2s, box-shadow 0.2s;
    animation: slideUp 0.4s ease forwards;
    opacity: 0;
    transform: translateY(20px);
}

.question-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
    border-color: rgba(59, 130, 246, 0.3);
}

.empty-search-result {
    background-color: var(--surface-color);
    border: 1px dashed var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    padding: 2rem;
    text-align: center;
}

.question-source {
    color: var(--text-secondary);
    font-size: 0.85rem;
    margin-bottom: 0.75rem;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.question-header {
    display: flex;
    align-items: flex-start;
    gap: 1rem;
    margin-bottom: 1.25rem;
}

.question-number {
    background-color: var(--primary-color);
    color: white;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    flex-shrink: 0;
}

.question-text {
    font-size: 1.1rem;
    font-weight: 500;
    color: var(--text-primary);
    line-height: 1.5;
    padding-top: 4px;
}

.options-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 0.75rem;
    padding-left: 3rem;
}

@media (min-width: 1024px) {
    .options-grid {
        grid-template-columns: 1fr 1fr;
    }
}

.option-item {
    background-color: rgba(15, 23, 42, 0.4);
    padding: 0.75rem 1rem;
    border-radius: var(--radius-md);
    border: 1px solid transparent;
    transition: all 0.2s;
    display: flex;
    align-items: center;
}

.option-item:hover {
    background-color: rgba(59, 130, 246, 0.1);
    border-color: rgba(59, 130, 246, 0.3);
}

.option-item.interactive {
    cursor: pointer;
}

.option-item.selected {
    background-color: rgba(59, 130, 246, 0.15);
    border-color: rgba(59, 130, 246, 0.5);
}

.option-item.free-points-option {
    background-color: rgba(59, 130, 246, 0.15);
    border-color: rgba(59, 130, 246, 0.5);
}

.option-item.free-points-option::after {
    content: "✓";
    margin-left: auto;
    color: var(--primary-color);
    font-weight: bold;
    font-size: 1.2rem;
}

.option-item.free-points-option .option-label {
    color: var(--primary-color);
}

.option-item.correct {
    background-color: rgba(16, 185, 129, 0.15);
    border-color: rgba(16, 185, 129, 0.5);
}

.option-item.correct::after {
    content: "✓";
    margin-left: auto;
    color: var(--success-color);
    font-weight: bold;
    font-size: 1.2rem;
}

.option-item.correct .option-label {
    color: var(--success-color);
}

.option-item.incorrect {
    background-color: rgba(239, 68, 68, 0.15);
    border-color: rgba(239, 68, 68, 0.5);
}

.option-item.incorrect::after {
    content: "✗";
    margin-left: auto;
    color: var(--danger-color);
    font-weight: bold;
    font-size: 1.2rem;
}

.option-item.incorrect .option-label {
    color: var(--danger-color);
}

.option-item.manual-setting {
    background-color: rgba(245, 158, 11, 0.15);
    border-color: rgba(245, 158, 11, 0.5);
}

.option-item.manual-setting::after {
    content: "●";
    margin-left: auto;
    color: #f59e0b;
    font-weight: bold;
    font-size: 1.2rem;
}

.option-item.manual-setting .option-label {
    color: #f59e0b;
}

.option-label {
    font-weight: 600;
    color: #94a3b8;
    margin-right: 0.75rem;
    font-family: monospace;
    font-size: 1.1rem;
}

/* Error State */
.error-message {
    color: var(--danger-color);
    background-color: rgba(239, 68, 68, 0.1);
    padding: 1rem;
    border-radius: var(--radius-md);
    margin-top: 1rem;
    border: 1px solid rgba(239, 68, 68, 0.2);
}

/* Utilities */
.hidden {
    display: none !important;
}

.action-dialog {
    background: var(--card-bg, #1e293b);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    padding: 1.5rem;
    width: 300px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.5);
    color: var(--text-color, #f8fafc);
}

.action-dialog::backdrop {
    background: rgba(0, 0, 0, 0.7);
}

.export-format-option {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    padding: 0.65rem;
    margin-bottom: 0.55rem;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background: rgba(15, 23, 42, 0.45);
    color: var(--text-primary);
    cursor: pointer;
}

.export-format-option:hover {
    border-color: rgba(59, 130, 246, 0.65);
}

.export-format-option input {
    accent-color: var(--primary-color);
}

.folder-select-dialog {
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    padding: 1.5rem;
    width: min(650px, calc(100vw - 2rem));
    box-shadow: 0 18px 45px rgba(0, 0, 0, 0.45);
}

.folder-select-dialog::backdrop {
    background: rgba(0, 0, 0, 0.7);
}

.folder-select-dialog h2 {
    font-size: 1.2rem;
    margin-bottom: 0.75rem;
}

.folder-select-label {
    display: block;
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 0.5rem;
}

.folder-select,
.folder-name-input {
    width: 100%;
    background: rgba(15, 23, 42, 0.65);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-primary);
    font: inherit;
    padding: 0.65rem 0.75rem;
}

.folder-select:focus,
.folder-name-input:focus {
    border-color: var(--primary-color);
    outline: none;
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.18);
}

.folder-create-row {
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 0.5rem;
    margin-top: 1rem;
}

.folder-dialog-actions {
    display: flex;
    justify-content: flex-end;
    gap: 0.5rem;
    margin-top: 1.25rem;
}

.random-year-section {
    background: rgba(15, 23, 42, 0.35);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 0.85rem;
}

.random-year-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 0.75rem;
}

.random-year-actions {
    display: flex;
    gap: 0.5rem;
}

.random-year-actions .secondary-btn {
    padding: 0.3rem 0.65rem;
    font-size: 0.8rem;
    border-radius: 8px;
}

.random-year-options {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(118px, 1fr));
    gap: 0.5rem;
    max-height: 220px;
    overflow-y: auto;
    padding-right: 0.25rem;
}

.random-year-option {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    min-height: 38px;
    background: rgba(30, 41, 59, 0.72);
    border: 1px solid rgba(148, 163, 184, 0.22);
    border-radius: 8px;
    padding: 0.45rem 0.6rem;
    color: var(--text-primary);
    cursor: pointer;
    user-select: none;
}

.random-year-option:hover {
    border-color: rgba(59, 130, 246, 0.6);
    background: rgba(59, 130, 246, 0.12);
}

.random-year-option input {
    width: 16px;
    height: 16px;
    accent-color: var(--primary-color);
    flex: 0 0 auto;
}

.random-year-text {
    min-width: 0;
    font-size: 0.88rem;
    line-height: 1.2;
}

.random-year-count {
    color: var(--text-secondary);
    font-size: 0.78rem;
}

.random-year-summary {
    color: var(--text-secondary);
    font-size: 0.82rem;
    margin-top: 0.65rem;
}

.random-display-section {
    margin-top: 0.9rem;
    background: rgba(15, 23, 42, 0.35);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 0.85rem;
}

.random-display-options {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0.65rem;
}

.random-display-option {
    display: flex;
    align-items: flex-start;
    gap: 0.55rem;
    background: rgba(30, 41, 59, 0.72);
    border: 1px solid rgba(148, 163, 184, 0.22);
    border-radius: 8px;
    padding: 0.65rem;
    cursor: pointer;
}

.random-display-option:hover {
    border-color: rgba(59, 130, 246, 0.6);
    background: rgba(59, 130, 246, 0.12);
}

.random-display-option input {
    margin-top: 0.2rem;
    accent-color: var(--primary-color);
}

.random-display-option strong {
    display: block;
    color: var(--text-primary);
    font-size: 0.9rem;
    line-height: 1.25;
}

.random-display-option small {
    display: block;
    color: var(--text-secondary);
    font-size: 0.78rem;
    line-height: 1.35;
    margin-top: 0.2rem;
}

.random-time-section {
    margin-top: 0.9rem;
    background: rgba(15, 23, 42, 0.35);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 0.85rem;
}

.random-time-option {
    display: flex;
    align-items: flex-start;
    gap: 0.55rem;
    cursor: pointer;
}

.random-time-option input {
    margin-top: 0.2rem;
    accent-color: var(--primary-color);
}

.random-time-option strong {
    display: block;
    color: var(--text-primary);
    font-size: 0.9rem;
    line-height: 1.25;
}

.random-time-option small {
    display: block;
    color: var(--text-secondary);
    font-size: 0.78rem;
    line-height: 1.35;
    margin-top: 0.2rem;
}

.exam-timer-badge {
    background-color: rgba(245, 158, 11, 0.18);
    color: #fbbf24;
}

.exam-timer-badge.timer-warning {
    background-color: rgba(239, 68, 68, 0.18);
    color: #fca5a5;
}

.random-next-btn {
    background-color: var(--primary-color);
    border-color: var(--primary-color);
    color: #fff;
    font-weight: 700;
    padding: 6px 16px;
    border-radius: 8px;
}

.random-next-btn:disabled {
    opacity: 0.55;
    cursor: not-allowed;
}

#random-prev-question-btn:disabled {
    opacity: 0.55;
    cursor: not-allowed;
}

.random-question-jump-grid {
    display: grid;
    grid-template-columns: repeat(10, 32px);
    gap: 6px;
    width: 100%;
    margin-top: 0.35rem;
}

.random-question-jump-btn {
    width: 32px;
    height: 32px;
    border: 1px solid rgba(148, 163, 184, 0.3);
    border-radius: 7px;
    background: rgba(15, 23, 42, 0.65);
    color: var(--text-secondary);
    cursor: pointer;
    font-size: 0.82rem;
    font-weight: 700;
}

.random-question-jump-btn:hover {
    border-color: rgba(59, 130, 246, 0.75);
    color: var(--text-primary);
}

.random-question-jump-btn.answered {
    background: rgba(16, 185, 129, 0.16);
    border-color: rgba(16, 185, 129, 0.5);
    color: #86efac;
}

.random-question-jump-btn.current {
    background: var(--primary-color);
    border-color: var(--primary-color);
    color: #fff;
}

@media (max-width: 820px) {
    .random-display-options {
        grid-template-columns: 1fr;
    }

    .random-question-jump-grid {
        grid-template-columns: repeat(8, 32px);
    }

    .app-layout {
        flex-direction: row;
        height: 100vh;
        min-height: 100vh;
        position: relative;
    }

    .sidebar {
        position: fixed;
        top: 0;
        left: 0;
        z-index: 1100;
        width: min(86vw, 360px);
        height: 100vh;
        max-height: none;
        border-right: 1px solid var(--border-color);
        border-bottom: none;
        transform: translateX(-105%);
        transition: transform 0.25s ease;
        box-shadow: 18px 0 40px rgba(0, 0, 0, 0.35);
    }

    .mobile-sidebar-open .sidebar {
        transform: translateX(0);
    }

    .sidebar-header {
        padding: 1rem;
    }

    .main-content {
        width: 100%;
        padding: 4rem 1rem 1rem;
    }

    .mobile-sidebar-toggle {
        display: inline-flex;
        align-items: center;
        justify-content: center;
        position: fixed;
        top: 0.75rem;
        left: 0.75rem;
        z-index: 1000;
        border: 1px solid rgba(59, 130, 246, 0.45);
        background: rgba(30, 41, 59, 0.92);
        color: #bfdbfe;
        border-radius: 10px;
        font-size: 0.9rem;
        font-weight: 700;
        padding: 0.55rem 0.75rem;
        box-shadow: 0 10px 25px rgba(0, 0, 0, 0.28);
    }

    .mobile-sidebar-backdrop {
        display: block;
        position: fixed;
        inset: 0;
        z-index: 1050;
        background: rgba(2, 6, 23, 0.62);
        backdrop-filter: blur(2px);
    }

    .app-header h1 {
        font-size: 2rem;
    }

    .upload-zone {
        padding: 3rem 1.25rem;
    }

    .results-header,
    .results-header>div {
        align-items: stretch;
        flex-direction: column;
    }

    .exam-title {
        max-width: 100%;
        white-space: normal;
    }

    .options-grid {
        padding-left: 0;
    }
}

@keyframes slideUp {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Added styles for add-question button and modal */
.add-question-btn {
    background-color: var(--primary-color);
    color: #fff;
    border: none;
    border-radius: var(--radius-md);
    padding: 0.4rem 0.8rem;
    font-size: 0.9rem;
    cursor: pointer;
    transition: background-color 0.2s, transform 0.2s;
    margin-left: 8px;
}

.add-question-btn:hover {
    background-color: var(--primary-hover);
    transform: scale(1.05);
}

/* Modal */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
}

.modal.hidden {
    display: none;
}

.modal-content {
    background: var(--surface-color);
    padding: 1.5rem;
    border-radius: var(--radius-lg);
    width: 90%;
    max-width: 500px;
    box-shadow: var(--shadow-md);
    color: var(--text-primary);
}

.modal-header {
    font-weight: 600;
    margin-bottom: 1rem;
    font-size: 1.1rem;
}

.modal-body input,
.modal-body textarea {
    width: 100%;
    margin-bottom: 0.8rem;
    padding: 0.4rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    background: var(--bg-color);
    color: var(--text-primary);
}

.modal-body .option-row {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.modal-body .option-row input {
    flex: 1;
}

.remove-option-btn,
.remove-image-btn {
    border: 1px solid rgba(239, 68, 68, 0.35);
    background: rgba(239, 68, 68, 0.1);
    color: #fca5a5;
    border-radius: 8px;
    cursor: pointer;
    font-size: 0.78rem;
    font-weight: 600;
}

.remove-option-btn {
    flex: 0 0 auto;
    padding: 0.35rem 0.55rem;
    margin-bottom: 0.8rem;
}

.remove-option-btn:hover,
.remove-image-btn:hover {
    background: rgba(239, 68, 68, 0.2);
    color: #fecaca;
}

.modal-footer {
    text-align: right;
    margin-top: 1rem;
}

.modal-footer button {
    margin-left: 0.5rem;
    padding: 0.4rem 0.8rem;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
}

.modal-footer .cancel-btn {
    background: #e5e7eb;
    color: #111827;
}

.modal-footer .confirm-btn {
    background: var(--primary-color);
    color: #fff;
}

.image-thumb {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
}

.question-image-preview {
    display: flex;
    flex-wrap: wrap;
    gap: 0.6rem;
    margin-top: 0.5rem;
}

.image-thumb-wrap {
    position: relative;
    width: 84px;
    height: 84px;
}

.remove-image-btn {
    position: absolute;
    top: -7px;
    right: -7px;
    width: 24px;
    height: 24px;
    padding: 0;
    line-height: 1;
}

.admin-login-btn {
    width: 100%;
    padding: 8px 12px;
    border: 1px dashed var(--primary-color);
    background: rgba(59, 130, 246, 0.05);
    color: var(--primary-color);
    border-radius: 6px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    font-weight: 500;
    font-size: 0.85rem;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.admin-login-btn:hover {
    background: rgba(59, 130, 246, 0.15);
    transform: translateY(-1px);
    box-shadow: 0 4px 6px -1px rgba(59, 130, 246, 0.1), 0 2px 4px -1px rgba(59, 130, 246, 0.06);
}

.admin-login-btn.unlocked {
    border: 1px solid var(--success-color);
    background: rgba(16, 185, 129, 0.08);
    color: var(--success-color);
}

.admin-login-btn.unlocked:hover {
    background: rgba(16, 185, 129, 0.18);
}

/* ==========================================
   Home Screen & Glassmorphism Dashboards
   ========================================== */
.home-screen {
    width: 100vw;
    min-height: 100vh;
    background: radial-gradient(circle at 10% 20%, #1e1b4b 0%, #0f172a 100%);
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow-x: hidden;
    padding: 2rem 1rem;
    box-sizing: border-box;
}

/* Background Glowing Orbs */
.home-screen::before,
.home-screen::after {
    content: "";
    position: absolute;
    width: min(35vw, 400px);
    height: min(35vw, 400px);
    border-radius: 50%;
    filter: blur(120px);
    z-index: 1;
    pointer-events: none;
    opacity: 0.15;
}

.home-screen::before {
    background: #6366f1;
    top: 15%;
    left: 10%;
}

.home-screen::after {
    background: #8b5cf6;
    bottom: 15%;
    right: 10%;
}

.home-container {
    width: 100%;
    max-width: 1100px;
    z-index: 2;
    position: relative;
    animation: homeFadeIn 0.8s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

@keyframes homeFadeIn {
    from {
        opacity: 0;
        transform: translateY(20px) scale(0.98);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

.home-header {
    text-align: center;
    margin-bottom: 3.5rem;
}

.home-logo {
    font-size: 4rem;
    margin-bottom: 0.75rem;
    display: inline-block;
    filter: drop-shadow(0 0 15px rgba(99, 102, 241, 0.4));
    animation: homeFloat 6s ease-in-out infinite;
}

@keyframes homeFloat {
    0% { transform: translateY(0px) rotate(0deg); }
    50% { transform: translateY(-10px) rotate(3deg); }
    100% { transform: translateY(0px) rotate(0deg); }
}

.home-title {
    font-size: clamp(2rem, 5vw, 3.25rem);
    font-weight: 800;
    margin-bottom: 0.85rem;
    letter-spacing: -0.03em;
    background: linear-gradient(135deg, #38bdf8 0%, #818cf8 50%, #c084fc 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    text-shadow: 0 0 40px rgba(129, 140, 248, 0.15);
}

.home-subtitle {
    font-size: clamp(0.95rem, 2vw, 1.15rem);
    color: var(--text-secondary);
    max-width: 650px;
    margin: 0 auto;
    line-height: 1.6;
    opacity: 0.85;
}

.home-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
}

@media (max-width: 768px) {
    .home-grid {
        grid-template-columns: 1fr;
    }
    .home-header {
        margin-bottom: 2rem;
    }
}

.home-card {
    background: rgba(30, 41, 59, 0.45);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid rgba(255, 255, 255, 0.08);
    border-radius: 24px;
    padding: 2.25rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 1.75rem;
    position: relative;
    overflow: hidden;
    box-shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.5);
    transition: all 0.4s cubic-bezier(0.16, 1, 0.3, 1);
}

.home-card:hover {
    transform: translateY(-6px);
    background: rgba(30, 41, 59, 0.6);
    border-color: var(--hover-border);
    box-shadow: 0 20px 40px -15px rgba(0, 0, 0, 0.6), var(--hover-glow);
}

.card-primary {
    --hover-border: rgba(99, 102, 241, 0.45);
    --hover-glow: 0 0 30px rgba(99, 102, 241, 0.2);
}

.card-cyan {
    --hover-border: rgba(6, 182, 212, 0.45);
    --hover-glow: 0 0 30px rgba(6, 182, 212, 0.2);
}

.card-violet {
    --hover-border: rgba(139, 92, 246, 0.45);
    --hover-glow: 0 0 30px rgba(139, 92, 246, 0.2);
}

.card-blue {
    --hover-border: rgba(59, 130, 246, 0.45);
    --hover-glow: 0 0 30px rgba(59, 130, 246, 0.2);
}

.card-icon {
    font-size: 2.75rem;
    width: 68px;
    height: 68px;
    background: rgba(255, 255, 255, 0.03);
    border-radius: 18px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    transition: all 0.4s cubic-bezier(0.16, 1, 0.3, 1);
    border: 1px solid rgba(255, 255, 255, 0.05);
}

.home-card:hover .card-icon {
    transform: scale(1.1) rotate(6deg);
    background: rgba(255, 255, 255, 0.07);
    border-color: var(--hover-border);
}

.card-content {
    flex: 1;
}

.card-title {
    font-size: 1.3rem;
    font-weight: 700;
    margin-bottom: 0.6rem;
    color: #f8fafc;
    transition: color 0.3s ease;
}

.home-card:hover .card-title {
    color: #fff;
}

.card-desc {
    font-size: 0.92rem;
    color: var(--text-secondary);
    line-height: 1.55;
    transition: color 0.3s ease;
}

.home-card:hover .card-desc {
    color: #cbd5e1;
}

.card-arrow {
    font-size: 1.6rem;
    color: var(--text-secondary);
    opacity: 0.3;
    transition: all 0.4s cubic-bezier(0.16, 1, 0.3, 1);
}

.home-card:hover .card-arrow {
    transform: translateX(6px);
    opacity: 1;
    color: #f8fafc;
}

.home-footer {
    text-align: center;
    margin-top: 4.5rem;
    font-size: 0.85rem;
    color: var(--text-secondary);
    opacity: 0.5;
    letter-spacing: 0.05em;
}

/* Sidebar Home Button Style */
.go-home-btn {
    transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

.go-home-btn:hover {
    background: rgba(59, 130, 246, 0.15) !important;
    transform: scale(1.01);
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.15);
}

/* Smooth Fade and Scale Animations for View Switching */
.view-transition {
    animation: viewFadeIn 0.5s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

@keyframes viewFadeIn {
    from {
        opacity: 0;
        transform: translateY(12px) scale(0.995);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

/* Focused Exam Mode Styles (測驗/讀卷專屬滿版模式) */
.focused-exam-mode #sidebar {
    display: none !important;
}

.focused-exam-mode .mobile-sidebar-toggle,
.focused-exam-mode .mobile-sidebar-backdrop {
    display: none !important;
}

.focused-exam-mode .question-search-bar {
    display: none !important;
}

.focused-exam-mode #upload-zone {
    display: none !important;
}

.focused-exam-mode #manual-input-btn {
    display: none !important;
}

.focused-exam-mode #show-answers-btn {
    display: none !important;
}

.focused-exam-mode .main-content {
    padding: 2rem 1.5rem !important;
}

.focused-exam-mode .content-container {
    max-width: 1000px !important;
}

/* --- Batch Upload & Answer Matching UI --- */
.batch-upload-list {
    max-height: 280px;
    overflow-y: auto;
    margin-top: 12px;
    margin-bottom: 12px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background: rgba(15, 23, 42, 0.4);
    padding: 4px;
}

.batch-upload-row {
    padding: 12px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.batch-upload-row:last-child {
    border-bottom: none;
}

.batch-upload-exam-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-weight: 500;
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.batch-upload-fields {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 8px;
}

@media (max-width: 580px) {
    .batch-upload-fields {
        grid-template-columns: 1fr;
    }
}

.batch-upload-answer-sec {
    display: flex;
    align-items: center;
    gap: 8px;
    background: rgba(30, 41, 59, 0.6);
    padding: 6px 10px;
    border-radius: 6px;
    font-size: 0.85rem;
    border: 1px solid rgba(59, 130, 246, 0.15);
}

.batch-upload-answer-label {
    white-space: nowrap;
    color: var(--text-secondary);
}

.batch-upload-answer-select {
    flex: 1;
    background: rgba(15, 23, 42, 0.8);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    color: var(--text-primary);
    padding: 4px;
    font-size: 0.82rem;
    outline: none;
}

.batch-upload-answer-select:focus {
    border-color: var(--primary-color);
}

.ans-upload-label {
    background-color: rgba(59, 130, 246, 0.1);
    color: #60a5fa;
    border: 1px solid rgba(59, 130, 246, 0.3);
    padding: 4px 8px;
    border-radius: 4px;
    font-size: 0.78rem;
    cursor: pointer;
    white-space: nowrap;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 4px;
    transition: all 0.2s;
}

.ans-upload-label:hover {
    background-color: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.ans-match-badge {
    font-size: 0.72rem;
    padding: 1px 5px;
    border-radius: 4px;
    font-weight: 600;
    white-space: nowrap;
}

.ans-match-badge.matched {
    background-color: rgba(16, 185, 129, 0.2);
    color: var(--success-color);
}

.ans-match-badge.unmatched {
    background-color: rgba(239, 68, 68, 0.15);
    color: #fca5a5;
}