/* Modern Police Blue & Glassmorphism Theme */
:root {
    --bg-dark: #0f172a;
    --bg-card: rgba(30, 41, 59, 0.85);
    --bg-card-hover: rgba(51, 65, 85, 0.9);
    --accent-blue: #3b82f6;
    --accent-blue-hover: #2563eb;
    --accent-gold: #f59e0b;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    --border-color: rgba(255, 255, 255, 0.12);
    --success-color: #10b981;
    --danger-color: #ef4444;
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --shadow-glow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
    --transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;
    touch-action: manipulation;
}

body {
    background-color: var(--bg-dark);
    background-image: 
        radial-gradient(at 0% 0%, rgba(59, 130, 246, 0.15) 0px, transparent 50%),
        radial-gradient(at 100% 100%, rgba(245, 158, 11, 0.1) 0px, transparent 50%);
    background-attachment: fixed;
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 0 16px;
    width: 100%;
}

/* Header */
.app-header {
    background: rgba(15, 23, 42, 0.9);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-content {
    max-width: 1100px;
    margin: 0 auto;
    padding: 12px 20px;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

@media (min-width: 768px) {
    .header-content {
        flex-direction: row;
        align-items: center;
        justify-content: space-between;
    }
}

.brand {
    display: flex;
    align-items: center;
    gap: 12px;
}

.brand-icon {
    font-size: 28px;
    color: var(--accent-gold);
}

.brand-text h1 {
    font-size: 18px;
    font-weight: 700;
    color: #ffffff;
    letter-spacing: 0.5px;
}

.sub-title {
    font-size: 12px;
    color: var(--text-secondary);
}

/* Nav Buttons */
.main-nav {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.nav-btn {
    background: rgba(255, 255, 255, 0.06);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    padding: 8px 14px;
    border-radius: var(--radius-sm);
    font-size: 13px;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 6px;
    transition: var(--transition);
}

.nav-btn:hover {
    background: rgba(255, 255, 255, 0.12);
    color: #fff;
}

.nav-btn.active {
    background: var(--accent-blue);
    color: #fff;
    border-color: var(--accent-blue);
    box-shadow: none;
}

.nav-btn.highlight {
    border-color: var(--accent-gold);
    color: var(--accent-gold);
}

.nav-btn.highlight:hover, .nav-btn.highlight.active {
    background: var(--accent-gold);
    color: #0f172a;
}

.badge {
    background: rgba(255, 255, 255, 0.2);
    padding: 2px 6px;
    border-radius: 10px;
    font-size: 11px;
}

/* Category Filter Bar */
.category-bar {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 12px 20px;
    background: var(--bg-card);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.25);
}

.cat-label {
    font-size: 13px;
    font-weight: 600;
    color: var(--accent-gold);
    white-space: nowrap;
    display: flex;
    align-items: center;
    gap: 8px;
    flex-shrink: 0;
}

.cat-tags {
    display: flex;
    gap: 10px;
    overflow-x: auto;
    padding-bottom: 2px;
    flex: 1;
    scrollbar-width: none;
}

.cat-tags::-webkit-scrollbar {
    display: none;
}

.cat-tag {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    color: var(--text-secondary);
    padding: 6px 16px;
    border-radius: 20px;
    font-size: 13px;
    font-weight: 500;
    cursor: pointer;
    white-space: nowrap;
    transition: var(--transition);
}

.cat-tag:hover {
    background: rgba(255, 255, 255, 0.12);
    color: #fff;
    border-color: rgba(255, 255, 255, 0.25);
}

.cat-tag.active {
    background: linear-gradient(135deg, #3b82f6, #2563eb);
    color: #fff;
    border-color: #60a5fa;
    box-shadow: none;
}

/* Paper Selector Bar (Top Bank Selector) */
.paper-bar {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 12px;
    padding: 14px 20px;
    background: var(--bg-card);
    border-radius: var(--radius-md);
    border: 1px solid rgba(59, 130, 246, 0.25);
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.2);
}

.paper-label {
    font-size: 14px;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 6px;
    white-space: nowrap;
}

.paper-label i {
    color: var(--accent-gold);
}

.paper-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.paper-tag {
    background: rgba(255, 255, 255, 0.06);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    padding: 6px 14px;
    border-radius: 20px;
    font-size: 13px;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 6px;
}

.paper-tag:hover {
    background: rgba(255, 255, 255, 0.14);
    color: #fff;
    border-color: rgba(255, 255, 255, 0.3);
}

.paper-tag.active {
    background: linear-gradient(135deg, #10b981, #059669);
    color: #fff;
    border-color: #34d399;
    box-shadow: none;
}

.paper-tag .badge-count {
    background: rgba(0, 0, 0, 0.25);
    padding: 1px 7px;
    border-radius: 10px;
    font-size: 11px;
}

.q-paper-badge {
    background: rgba(16, 185, 129, 0.15);
    color: #34d399;
    border: 1px solid rgba(52, 211, 153, 0.35);
    font-size: 12px;
    font-weight: 600;
    padding: 3px 10px;
    border-radius: 4px;
    display: inline-flex;
    align-items: center;
    gap: 4px;
}

/* Exam Timer Bar */
.timer-card {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 14px 22px;
    background: var(--bg-card);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.25);
    transition: var(--transition);
}

.timer-info {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 14px;
    font-weight: 600;
    color: var(--text-primary);
}

.timer-info i {
    font-size: 16px;
    color: var(--accent-blue);
    transition: var(--transition);
}

#exam-timer {
    font-family: 'Consolas', 'Monaco', monospace;
    font-size: 18px;
    font-weight: 800;
    color: var(--accent-blue);
    letter-spacing: 1px;
    background: rgba(59, 130, 246, 0.12);
    padding: 4px 12px;
    border-radius: 6px;
    border: 1px solid rgba(59, 130, 246, 0.25);
    transition: var(--transition);
}

/* Last 2 minutes warning style (Pale Yellow) */
.timer-card.warning-time {
    border-color: rgba(245, 158, 11, 0.45);
    box-shadow: 0 6px 20px rgba(245, 158, 11, 0.2);
}

.timer-card.warning-time .timer-info i {
    color: #f59e0b;
}

.timer-card.warning-time #exam-timer {
    color: #fbbf24;
    background: rgba(245, 158, 11, 0.15);
    border-color: rgba(245, 158, 11, 0.35);
}

.btn-submit-exam {
    display: flex;
    align-items: center;
    gap: 8px;
    background: linear-gradient(135deg, #3b82f6, #2563eb);
    color: #ffffff;
    border: none;
    padding: 8px 20px;
    border-radius: var(--radius-sm);
    font-size: 13px;
    font-weight: 600;
    cursor: pointer;
    box-shadow: none;
    transition: var(--transition);
}

.btn-submit-exam:hover {
    background: linear-gradient(135deg, #60a5fa, #3b82f6);
    transform: translateY(-1px);
    box-shadow: none;
}

/* Main Layout */
.app-main {
    padding-top: 24px;
    padding-bottom: 90px;
    flex: 1;
}

.glass-panel {
    background: var(--bg-card);
    backdrop-filter: blur(16px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-glow);
}

.view-panel {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.hidden {
    display: none !important;
}

/* Toolbar */
.toolbar-card {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 14px 20px;
    background: var(--bg-card);
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
}

.tag {
    background: rgba(59, 130, 246, 0.15);
    color: var(--accent-blue);
    padding: 4px 10px;
    border-radius: 6px;
    font-size: 13px;
    font-weight: 600;
    border: 1px solid rgba(59, 130, 246, 0.3);
}

.question-progress {
    font-size: 14px;
    color: var(--text-secondary);
    margin-left: 12px;
}

.tools-actions {
    display: flex;
    align-items: center;
    gap: 14px;
}

.icon-btn {
    background: rgba(255, 255, 255, 0.06);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    padding: 6px 12px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 13px;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 6px;
}

.icon-btn:hover {
    background: rgba(255, 255, 255, 0.15);
    color: #fff;
}

.icon-btn.active-fav {
    color: var(--accent-gold);
    border-color: var(--accent-gold);
}

/* Toggle Switch */
.switch-label {
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    font-size: 13px;
    color: var(--text-secondary);
    white-space: nowrap;
    user-select: none;
}

.switch-label input {
    display: none;
}

.slider {
    width: 36px;
    height: 20px;
    background-color: rgba(255, 255, 255, 0.2);
    border-radius: 20px;
    position: relative;
    transition: var(--transition);
    flex-shrink: 0;
}

.slider::before {
    content: "";
    position: absolute;
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background-color: white;
    top: 3px;
    left: 3px;
    transition: var(--transition);
}

input:checked + .slider {
    background-color: var(--accent-blue);
}

input:checked + .slider::before {
    transform: translateX(16px);
}

/* Question Card */
.question-card {
    padding: 24px;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.question-header {
    display: flex;
    gap: 10px;
    align-items: center;
}

.q-type-badge {
    background: var(--accent-gold);
    color: #0f172a;
    font-size: 12px;
    font-weight: 700;
    padding: 4px 10px;
    border-radius: 4px;
}

.q-source-badge {
    background: rgba(255, 255, 255, 0.08);
    color: var(--text-secondary);
    font-size: 12px;
    padding: 4px 10px;
    border-radius: 4px;
}

.question-stem {
    font-size: 17px;
    line-height: 1.6;
    font-weight: 600;
    color: #ffffff;
}

/* Options */
.options-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.option-item {
    background: rgba(255, 255, 255, 0.04);
    border: 1px solid var(--border-color);
    padding: 14px 18px;
    border-radius: var(--radius-md);
    cursor: pointer;
    font-size: 15px;
    line-height: 1.6;
    transition: var(--transition);

    display: flex;
    align-items: flex-start;
    gap: 12px;
}

.opt-key {
    font-weight: 700;
    color: var(--accent-gold);
    min-width: 22px;
    font-size: 16px;
    line-height: 1.5;
    flex-shrink: 0;
}

.opt-val {
    flex: 1;
    color: #f8fafc;
    word-break: break-word;
    overflow-wrap: break-word;
    white-space: normal;
}

.option-item:hover {
    background: var(--bg-card-hover);
    border-color: rgba(59, 130, 246, 0.4);
}

.option-item.selected {
    background: rgba(59, 130, 246, 0.15);
    border-color: var(--accent-blue);
    color: #fff;
}

.option-item.correct {
    background: rgba(16, 185, 129, 0.18) !important;
    border-color: var(--success-color) !important;
    color: #fff;
}

.option-item.wrong {
    background: rgba(239, 68, 68, 0.18) !important;
    border-color: var(--danger-color) !important;
    color: #fff;
}

/* Explanation Box */
.explanation-box {
    margin-top: 10px;
    padding: 16px 20px;
    background: rgba(15, 23, 42, 0.6);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
}

.result-badge {
    display: inline-block;
    padding: 4px 12px;
    border-radius: 6px;
    font-weight: 700;
    font-size: 14px;
    margin-bottom: 12px;
}

.result-badge.correct {
    background: rgba(16, 185, 129, 0.2);
    color: var(--success-color);
    border: 1px solid var(--success-color);
}

.result-badge.wrong {
    background: rgba(239, 68, 68, 0.2);
    color: var(--danger-color);
    border: 1px solid var(--danger-color);
}

.exp-content h4 {
    color: var(--accent-gold);
    font-size: 14px;
    margin-bottom: 8px;
    display: flex;
    align-items: center;
    gap: 6px;
}

.exp-content p {
    font-size: 14px;
    line-height: 1.6;
    color: var(--text-secondary);
}

/* Bottom Navigation Dock */
.bottom-dock {
    position: fixed;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    gap: 16px;
    z-index: 90;
    width: 90%;
    max-width: 400px;
}

.dock-btn {
    flex: 1;
    padding: 14px 20px;
    background: rgba(30, 41, 59, 0.95);
    backdrop-filter: blur(12px);
    border: 1px solid var(--border-color);
    color: #fff;
    border-radius: 30px;
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;

    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    box-shadow: none;
    transition: var(--transition);
}

.dock-btn:hover {
    background: var(--bg-card-hover);
    transform: translateY(-2px);
}

.dock-btn.primary {
    background: var(--accent-blue);
    border-color: var(--accent-blue);
    box-shadow: none;
}

.dock-btn.primary:hover {
    background: var(--accent-blue-hover);
}

/* Document Reader */
.doc-container {
    padding: 0;
    display: flex;
    flex-direction: column;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-glow);
}

.doc-header {
    position: sticky;
    top: 80px;
    z-index: 95;
    background: transparent;
    padding: 0;
    margin: 0 0 20px 0;
    border: none;
    box-shadow: none;
}

.doc-sec-title.doc-main-sec-title {
    line-height: 1.5;
    text-align: center;
    margin-top: 12px;
    margin-bottom: 24px;
}

.doc-subtitle {
    text-align: center;
    color: var(--text-secondary);
    font-size: 13px;
    margin: -10px 0 24px 0;
    letter-spacing: 0.5px;
}

.doc-search-box {
    display: flex;
    align-items: center;
    background: rgba(15, 23, 42, 0.92);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid rgba(255, 255, 255, 0.12);
    border-radius: 12px;
    padding: 10px 18px;
    gap: 12px;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.45);
    transition: var(--transition);
}

.doc-search-box:focus-within,
.doc-search-box:hover {
    border-color: rgba(59, 130, 246, 0.5);
    box-shadow: 0 8px 28px rgba(0, 0, 0, 0.55), 0 0 0 1px rgba(59, 130, 246, 0.25);
}

.doc-search-box input {
    background: transparent;
    border: none;
    outline: none;
    color: #fff;
    font-size: 14px;
    flex: 1;
}

.btn-clear-search {
    background: transparent;
    border: none;
    outline: none;
    color: var(--text-secondary);
    font-size: 15px;
    cursor: pointer;
    padding: 4px 8px;
    border-radius: 50%;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
}

.btn-clear-search:hover {
    color: #ffffff;
    background: rgba(255, 255, 255, 0.15);
}

.doc-search-nav {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 0 4px;
    border-right: 1px solid rgba(255, 255, 255, 0.15);
    margin-right: 4px;
}

.search-count-text {
    font-size: 13px;
    color: var(--accent-gold);
    font-weight: 700;
    white-space: nowrap;
    padding: 0 4px;
}

.btn-search-nav {
    background: rgba(255, 255, 255, 0.08);
    border: 1px solid rgba(255, 255, 255, 0.15);
    color: #cbd5e1;
    border-radius: 4px;
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    font-size: 12px;
    transition: var(--transition);
}

.btn-search-nav:hover {
    background: var(--accent-blue);
    border-color: var(--accent-blue);
    color: #ffffff;
}

mark.highlight {
    background: rgba(245, 158, 11, 0.18);
    color: #fef08a;
    border-bottom: 1px dashed rgba(245, 158, 11, 0.6);
    border-radius: 2px;
    padding: 0 4px;
    margin: 0 1px;
    font-weight: 500;
}

mark.highlight.active-match {
    background: #3b82f6 !important;
    color: #ffffff !important;
    font-weight: 700;
    border-radius: 3px;
    padding: 1px 5px;
    margin: 0 1px;
    display: inline;
    border-bottom: none;
    box-shadow: none !important;
    animation: none !important;
}

.doc-body {
    padding: 28px;
}

.doc-sec-title {
    text-align: center;
    font-size: 1.4rem;
    font-weight: 800;
    color: var(--accent-blue);
    border-bottom: 2px solid rgba(59, 130, 246, 0.3);
    padding-bottom: 10px;
    margin: 36px 0 20px 0;
    letter-spacing: 0.5px;
}

/* TOC Table of Contents Card */
.doc-toc-container {
    background: rgba(15, 23, 42, 0.7);
    border: 1px solid rgba(245, 158, 11, 0.35);
    border-radius: var(--radius-md);
    padding: 18px 24px;
    margin: 20px 0 28px 0;
    max-width: 420px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.25);
}

.doc-toc-title {
    font-size: 16px;
    font-weight: 700;
    color: var(--accent-gold);
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    gap: 8px;
    border-bottom: 1px solid rgba(245, 158, 11, 0.2);
    padding-bottom: 8px;
}

.doc-toc-list {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.doc-toc-item {
    font-size: 14px;
    color: #e2e8f0;
    text-align: left;
    padding: 6px 12px;
    border-left: 3px solid var(--accent-blue);
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
    line-height: 1.5;
    cursor: pointer;
    user-select: none;
    transition: var(--transition);
}

.toc-icon {
    font-size: 11px;
    color: var(--accent-blue);
    margin-right: 6px;
    transition: var(--transition);
}

.doc-toc-item:hover {
    color: var(--accent-gold);
    background: rgba(59, 130, 246, 0.12);
    border-left-color: var(--accent-gold);
    transform: translateX(6px);
}

.doc-toc-item:hover .toc-icon {
    color: var(--accent-gold);
    transform: translateX(3px);
}

@keyframes flashGold {
    0% { background: rgba(245, 158, 11, 0.35); box-shadow: 0 0 16px rgba(245, 158, 11, 0.4); }
    100% { background: transparent; box-shadow: none; }
}

.flash-highlight {
    animation: flashGold 2s ease-out;
    border-radius: var(--radius-sm);
    padding: 4px 8px;
}

.doc-chapter-title {
    text-align: center;
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--accent-gold);
    margin: 32px 0 16px 0;
    letter-spacing: 1px;
    text-shadow: 0 0 10px rgba(245, 158, 11, 0.25);
}

.doc-p {
    font-size: 15px;
    line-height: 1.85;
    color: #e2e8f0;
    margin-bottom: 14px;
    text-align: justify;
    word-break: break-word;
}

mark.highlight {
    background-color: var(--accent-gold);
    color: #0f172a;
    padding: 2px 4px;
    border-radius: 4px;
    font-weight: 700;
}

/* Modals */
.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(8px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 200;
    padding: 16px;
}

.modal-card {
    width: 100%;
    max-width: 650px;
    max-height: 85vh;
    padding: 24px;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 12px;
}

.btn-close {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    font-size: 20px;
    cursor: pointer;
}

.modal-legend {
    display: flex;
    gap: 16px;
    font-size: 12px;
    color: var(--text-secondary);
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 6px;
}

.legend-box {
    width: 12px;
    height: 12px;
    border-radius: 3px;
    display: inline-block;
}

.legend-box.current { background: var(--accent-blue); }
.legend-box.correct { background: var(--success-color); }
.legend-box.wrong { background: var(--danger-color); }
.legend-box.unanswered { background: rgba(255, 255, 255, 0.1); }

.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(44px, 1fr));
    gap: 10px;
    margin-top: 10px;
}

.grid-item {
    aspect-ratio: 1;
    background: rgba(255, 255, 255, 0.06);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 13px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
}

.grid-item:hover {
    background: rgba(255, 255, 255, 0.2);
}

.grid-item.current { border-color: var(--accent-blue); color: var(--accent-blue); font-weight: 800; }
.grid-item.correct { background: rgba(16, 185, 129, 0.25); border-color: var(--success-color); color: #fff; }
.grid-item.wrong { background: rgba(239, 68, 68, 0.25); border-color: var(--danger-color); color: #fff; }

/* Score Card Modal */
.score-card {
    text-align: center;
    gap: 20px;
}

.trophy-icon {
    font-size: 48px;
    color: var(--accent-gold);
}

.score-num {
    font-size: 56px;
    font-weight: 800;
    color: var(--accent-gold);
}

.score-details {
    display: flex;
    justify-content: space-around;
    padding: 14px;
    background: rgba(15, 23, 42, 0.6);
    border-radius: var(--radius-md);
    font-size: 14px;
}

.text-success { color: var(--success-color); font-weight: 700; }
.text-danger { color: var(--danger-color); font-weight: 700; }

/* Multiple Choice Confirm Action Bar */
.multi-confirm-box {
    display: flex;
    justify-content: flex-end;
    align-items: center;
    margin-top: 18px;
    padding-top: 14px;
    border-top: 1px dashed rgba(255, 255, 255, 0.12);
}

.btn-confirm-multi {
    background: linear-gradient(135deg, #3b82f6 0%, #1d4ed8 100%);
    color: #ffffff;
    border: 1px solid rgba(255, 255, 255, 0.25);
    padding: 12px 28px;
    border-radius: 30px;
    font-size: 15px;
    font-weight: 700;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    letter-spacing: 0.5px;
    box-shadow: none;
    transition: var(--transition);
}

.btn-confirm-multi:hover {
    background: linear-gradient(135deg, #2563eb 0%, #1e40af 100%);
    transform: translateY(-2px);
    box-shadow: none;
}

.btn-confirm-multi:active {
    transform: translateY(0);
    box-shadow: none;
}

.btn-confirm-multi.has-selection {
    background: linear-gradient(135deg, #3b82f6 0%, #1d4ed8 100%);
    border-color: rgba(255, 255, 255, 0.25);
    box-shadow: none;
}

/* ==========================================================================
   Mobile Responsive Layout (适配手机端 - 业界App级移动端体验)
   ========================================================================== */
@media (max-width: 768px) {
    /* Container & Spacing */
    .container {
        padding: 0 10px;
    }

    .app-main {
        padding-top: 10px;
        padding-bottom: 85px;
    }

    /* Header Compact Mode */
    .header-content {
        padding: 8px 12px;
        gap: 8px;
    }

    .brand-icon {
        font-size: 22px;
    }

    .brand-text h1 {
        font-size: 15px;
    }

    .sub-title {
        display: none; /* Hide subtitle on mobile to save vertical space */
    }

    /* Nav Buttons: Single line horizontal scrollable container */
    .main-nav {
        flex-wrap: nowrap;
        overflow-x: auto;
        -webkit-overflow-scrolling: touch;
        gap: 6px;
        padding-bottom: 2px;
        scrollbar-width: none;
    }

    .main-nav::-webkit-scrollbar {
        display: none;
    }

    .nav-btn {
        padding: 6px 11px;
        font-size: 12px;
        white-space: nowrap;
        flex-shrink: 0;
        border-radius: 20px;
    }

    /* Paper & Category Selectors: Horizontal scroll */
    .paper-bar, .category-bar {
        padding: 8px 12px;
        gap: 8px;
        border-radius: var(--radius-sm);
    }

    .paper-label, .cat-label {
        font-size: 12px;
        flex-shrink: 0;
    }

    .paper-tags, .cat-tags {
        flex-wrap: nowrap;
        overflow-x: auto;
        -webkit-overflow-scrolling: touch;
        gap: 6px;
        scrollbar-width: none;
    }

    .paper-tags::-webkit-scrollbar, .cat-tags::-webkit-scrollbar {
        display: none;
    }

    .paper-tag, .cat-tag {
        padding: 4px 10px;
        font-size: 12px;
        white-space: nowrap;
        flex-shrink: 0;
    }

    /* Toolbar Card Fixes */
    .toolbar-card {
        padding: 8px 12px;
        flex-wrap: wrap;
        gap: 6px 10px;
        border-radius: var(--radius-sm);
    }

    .progress-info {
        display: flex;
        align-items: center;
        gap: 6px;
        flex-wrap: nowrap;
        min-width: 0;
    }

    .tag.category-tag {
        white-space: nowrap;
        max-width: 130px;
        overflow: hidden;
        text-overflow: ellipsis;
        display: inline-block;
        flex-shrink: 0;
        font-size: 12px;
        padding: 3px 8px;
    }

    .question-progress {
        font-size: 13px;
        margin-left: 0;
        white-space: nowrap;
        flex-shrink: 0;
    }

    .tools-actions {
        gap: 8px;
        margin-left: auto;
    }

    .switch-label {
        font-size: 11px;
        gap: 4px;
    }

    .slider {
        width: 30px;
        height: 16px;
    }

    .slider::before {
        width: 12px;
        height: 12px;
        top: 2px;
        left: 2px;
    }

    input:checked + .slider::before {
        transform: translateX(14px);
    }

    .icon-btn {
        padding: 4px 8px;
        font-size: 12px;
    }

    /* Question Card Density & Padding */
    .question-card {
        padding: 14px;
        gap: 12px;
        border-radius: var(--radius-md);
    }

    .question-header {
        gap: 8px;
    }

    .q-type-badge, .q-source-badge {
        font-size: 11px;
        padding: 3px 8px;
    }

    .question-stem {
        font-size: 15px;
        line-height: 1.5;
    }

    .options-list {
        gap: 8px;
    }

    .option-item {
        padding: 10px 12px;
        font-size: 14px;
        border-radius: var(--radius-sm);
        gap: 8px;
    }

    .opt-key {
        font-size: 14px;
        min-width: 18px;
    }

    .opt-val {
        font-size: 14px;
        line-height: 1.45;
    }

    .explanation-box {
        padding: 12px;
    }

    .exp-content h4 {
        font-size: 13px;
    }

    .exp-content p {
        font-size: 13px;
        line-height: 1.5;
    }

    /* Bottom Dock Bar Fixed at Screen Bottom */
    .bottom-dock {
        bottom: calc(10px + env(safe-area-inset-bottom, 0px));
        width: calc(100% - 20px);
        gap: 10px;
    }

    .dock-btn {
        padding: 11px 16px;
        font-size: 14px;
        border-radius: 25px;
    }
}