:root {
    
    --qa-primary: #2563eb;
    --qa-primary-light: #3b82f6;
    --qa-primary-dark: #1d4ed8;
    --qa-primary-darker: #1e40af;
    --qa-primary-bg: #eff6ff;
    --qa-primary-bg-hover: #dbeafe;
    --qa-accent: #0ea5e9;
    --qa-accent-light: #38bdf8;
    --qa-success: #10b981;
    --qa-success-bg: #ecfdf5;
    --qa-warning: #f59e0b;
    --qa-warning-bg: #fffbeb;
    --qa-error: #ef4444;
    --qa-error-bg: #fef2f2;
    --qa-bg: #f8fafc;
    --qa-bg-alt: #f1f5f9;
    --qa-surface: #ffffff;
    --qa-surface-hover: #f8fafc;
    --qa-border: #e2e8f0;
    --qa-border-light: #f1f5f9;
    --qa-border-hover: #cbd5e1;
    --qa-text: #0f172a;
    --qa-text-secondary: #475569;
    --qa-text-muted: #94a3b8;
    --qa-text-inverse: #ffffff;
    --qa-radius-xs: 6px;
    --qa-radius-sm: 8px;
    --qa-radius: 12px;
    --qa-radius-lg: 16px;
    --qa-radius-xl: 20px;
    --qa-shadow-xs: 0 1px 2px rgba(0,0,0,0.04);
    --qa-shadow-sm: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
    --qa-shadow: 0 2px 8px rgba(0,0,0,0.06), 0 1px 3px rgba(0,0,0,0.04);
    --qa-shadow-md: 0 4px 16px rgba(0,0,0,0.08), 0 2px 4px rgba(0,0,0,0.04);
    --qa-shadow-lg: 0 12px 32px rgba(0,0,0,0.1), 0 4px 8px rgba(0,0,0,0.04);
    --qa-shadow-xl: 0 20px 48px rgba(0,0,0,0.12), 0 8px 16px rgba(0,0,0,0.06);
    --qa-shadow-primary: 0 4px 14px rgba(37,99,235,0.25);
    --qa-shadow-primary-lg: 0 8px 24px rgba(37,99,235,0.3);
    --qa-transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    --qa-transition-fast: all 0.15s cubic-bezier(0.4, 0, 0.2, 1);
    --qa-transition-slow: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    --qa-max-width: 1080px;
    --qa-header-height: 64px;
    --qa-content-padding: 24px;
}

* { box-sizing: border-box; }

body.zk-qa {
    margin: 0;
    background: var(--qa-bg);
    color: var(--qa-text);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

a {
    color: var(--qa-primary);
    text-decoration: none;
    transition: var(--qa-transition-fast);
}
a:hover {
    color: var(--qa-primary-dark);
}

.qa-container {
    max-width: var(--qa-max-width);
    margin: 0 auto;
    padding: 0 var(--qa-content-padding);
}

.qa-header {
    background: rgba(255, 255, 255, 0.85);
    border-bottom: 1px solid var(--qa-border);
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: saturate(180%) blur(16px);
    -webkit-backdrop-filter: saturate(180%) blur(16px);
    transition: var(--qa-transition);
}
.qa-header.scrolled {
    box-shadow: var(--qa-shadow-sm);
    background: rgba(255, 255, 255, 0.92);
}

.qa-header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 var(--qa-content-padding);
    max-width: var(--qa-max-width);
    margin: 0 auto;
    gap: 16px;
    height: var(--qa-header-height);
}

.qa-logo a {
    font-size: 20px;
    font-weight: 700;
    color: var(--qa-text);
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 10px;
    letter-spacing: -0.02em;
    position: relative;
    padding-left: 40px;
    min-height: 32px;
    transition: var(--qa-transition-fast);
}
.qa-logo a:hover {
    color: var(--qa-primary);
}
.qa-logo a::before {
    content: "Q";
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    background: linear-gradient(135deg, var(--qa-primary) 0%, var(--qa-accent) 100%);
    color: #fff;
    border-radius: 10px;
    font-size: 16px;
    font-weight: 800;
    box-shadow: var(--qa-shadow-primary);
    transition: var(--qa-transition);
}
.qa-logo a:hover::before {
    transform: translateY(-50%) scale(1.05);
    box-shadow: var(--qa-shadow-primary-lg);
}

.qa-nav ul {
    list-style: none;
    display: flex;
    gap: 4px;
    margin: 0;
    padding: 0;
}
.qa-nav li { margin: 0; }
.qa-nav a {
    color: var(--qa-text-secondary);
    text-decoration: none;
    padding: 8px 16px;
    border-radius: var(--qa-radius-sm);
    font-size: 14px;
    font-weight: 500;
    transition: var(--qa-transition-fast);
    position: relative;
}
.qa-nav a:hover {
    color: var(--qa-primary);
    background: var(--qa-primary-bg);
}
.qa-nav a.active {
    color: var(--qa-primary);
    background: var(--qa-primary-bg);
    font-weight: 600;
}

.qa-main {
    padding: 36px 0 56px;
    min-height: calc(100vh - var(--qa-header-height) - 80px);
}

.qa-layout {
    display: flex;
    gap: 28px;
    align-items: flex-start;
}
.qa-layout-main {
    flex: 1;
    min-width: 0;
}

.qa-page-title {
    margin-bottom: 28px;
}
.qa-page-title h1 {
    font-size: 32px;
    margin: 0 0 10px;
    color: var(--qa-text);
    font-weight: 700;
    letter-spacing: -0.02em;
    line-height: 1.3;
}
.qa-page-sub {
    color: var(--qa-text-secondary);
    margin: 0;
    font-size: 15px;
    display: flex;
    align-items: center;
    gap: 6px;
}
.qa-page-sub strong {
    color: var(--qa-primary);
    font-weight: 700;
    font-size: 16px;
}

.qa-body {
    background: var(--qa-surface);
    border: 1px solid var(--qa-border);
    border-radius: var(--qa-radius-lg);
    padding: 8px 32px;
    box-shadow: var(--qa-shadow-sm);
}

.qa-cat {
    padding: 24px 0;
    border-bottom: 1px solid var(--qa-border-light);
}
.qa-cat:last-child { border-bottom: none; }

.qa-cat-title {
    font-size: 20px;
    color: var(--qa-text);
    margin: 0 0 18px;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 12px;
    letter-spacing: -0.01em;
}
.qa-cat-title::before {
    content: "";
    display: inline-block;
    width: 5px;
    height: 22px;
    background: linear-gradient(180deg, var(--qa-primary) 0%, var(--qa-accent) 100%);
    border-radius: 3px;
    flex-shrink: 0;
}

.qa-cards {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
}

.qa-card {
    border: 1px solid var(--qa-border);
    border-radius: var(--qa-radius);
    padding: 20px 22px;
    background: var(--qa-surface);
    transition: var(--qa-transition);
    cursor: pointer;
    position: relative;
    overflow: hidden;
    display: flex;
    flex-direction: column;
}
.qa-card::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 100%;
    background: linear-gradient(180deg, var(--qa-primary) 0%, var(--qa-accent) 100%);
    opacity: 0;
    transition: var(--qa-transition);
    border-radius: 4px 0 0 4px;
}
.qa-card::after {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, rgba(37,99,235,0.15), transparent);
    opacity: 0;
    transition: var(--qa-transition);
}
.qa-card:hover {
    border-color: var(--qa-primary-light);
    box-shadow: var(--qa-shadow-md);
    transform: translateY(-3px);
    background: var(--qa-surface-hover);
}
.qa-card:hover::before { opacity: 1; }
.qa-card:hover::after { opacity: 1; }

.qa-card-title {
    font-size: 16px;
    margin: 0 0 10px;
    font-weight: 600;
    line-height: 1.5;
    letter-spacing: -0.01em;
}
.qa-card-title a {
    color: var(--qa-text);
    text-decoration: none;
    display: block;
    transition: var(--qa-transition-fast);
}
.qa-card-title a:hover { color: var(--qa-primary); }

.qa-card-desc {
    font-size: 13.5px;
    color: var(--qa-text-secondary);
    margin: 0 0 14px;
    line-height: 1.65;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
    flex: 1;
}

.qa-card-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-top: auto;
}

.qa-card-count {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 12.5px;
    color: var(--qa-primary);
    background: var(--qa-primary-bg);
    padding: 5px 14px;
    border-radius: 20px;
    font-weight: 600;
    transition: var(--qa-transition-fast);
}
.qa-card:hover .qa-card-count {
    background: var(--qa-primary);
    color: #fff;
}
.qa-card-count::before {
    content: "";
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 16px;
    height: 16px;
    background: currentColor;
    -webkit-mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='white' stroke-width='2.5' stroke-linecap='round' stroke-linejoin='round'%3E%3Ccircle cx='12' cy='12' r='10'%3E%3C/circle%3E%3Cpath d='M9.09 9a3 3 0 0 1 5.83 1c0 2-3 3-3 3'%3E%3C/path%3E%3Cline x1='12' y1='17' x2='12.01' y2='17'%3E%3C/line%3E%3C/svg%3E") center/contain no-repeat;
    mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='white' stroke-width='2.5' stroke-linecap='round' stroke-linejoin='round'%3E%3Ccircle cx='12' cy='12' r='10'%3E%3C/circle%3E%3Cpath d='M9.09 9a3 3 0 0 1 5.83 1c0 2-3 3-3 3'%3E%3C/path%3E%3Cline x1='12' y1='17' x2='12.01' y2='17'%3E%3C/line%3E%3C/svg%3E") center/contain no-repeat;
    transition: var(--qa-transition-fast);
}

.qa-card-arrow {
    color: var(--qa-text-muted);
    font-size: 18px;
    transition: var(--qa-transition-fast);
    opacity: 0;
    transform: translateX(-4px);
}
.qa-card:hover .qa-card-arrow {
    opacity: 1;
    transform: translateX(0);
    color: var(--qa-primary);
}

.qa-breadcrumb {
    font-size: 13.5px;
    color: var(--qa-text-muted);
    margin-bottom: 18px;
    display: flex;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
}
.qa-breadcrumb a {
    color: var(--qa-text-secondary);
    text-decoration: none;
    transition: var(--qa-transition-fast);
}
.qa-breadcrumb a:hover { color: var(--qa-primary); }
.qa-breadcrumb .qa-breadcrumb-sep {
    color: var(--qa-text-muted);
    font-size: 12px;
}
.qa-breadcrumb span { color: var(--qa-text); font-weight: 500; }

.qa-article {
    background: var(--qa-surface);
    border: 1px solid var(--qa-border);
    border-radius: var(--qa-radius-lg);
    padding: 40px 44px;
    margin-bottom: 28px;
    box-shadow: var(--qa-shadow-sm);
}
.qa-article h1 {
    font-size: 30px;
    margin: 0 0 14px;
    color: var(--qa-text);
    font-weight: 700;
    line-height: 1.35;
    letter-spacing: -0.015em;
}

.qa-meta {
    font-size: 13.5px;
    color: var(--qa-text-muted);
    margin-bottom: 24px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--qa-border-light);
    display: flex;
    flex-wrap: wrap;
    gap: 8px 16px;
    align-items: center;
}
.qa-meta span {
    display: inline-flex;
    align-items: center;
    gap: 5px;
}
.qa-meta .qa-meta-label {
    color: var(--qa-text-muted);
}
.qa-meta .qa-meta-value {
    color: var(--qa-text-secondary);
    font-weight: 500;
}
.qa-meta .qa-meta-badge {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 3px 10px;
    background: var(--qa-primary-bg);
    color: var(--qa-primary);
    border-radius: 12px;
    font-weight: 600;
    font-size: 12.5px;
}

.qa-intro {
    color: var(--qa-text-secondary);
    margin-bottom: 28px;
    padding: 18px 22px;
    background: linear-gradient(135deg, var(--qa-primary-bg) 0%, #f0f9ff 100%);
    border-left: 4px solid var(--qa-primary);
    border-radius: 0 var(--qa-radius-sm) var(--qa-radius-sm) 0;
    font-size: 15px;
    line-height: 1.85;
    position: relative;
}
.qa-intro::before {
    content: "";
    position: absolute;
    top: 0;
    right: 0;
    width: 60px;
    height: 60px;
    background: radial-gradient(circle at top right, rgba(14,165,233,0.08), transparent 70%);
    border-radius: 0 var(--qa-radius-sm) 0 0;
    pointer-events: none;
}

.qa-accordion {
    border-top: 1px solid var(--qa-border-light);
    padding-top: 10px;
}
.qa-empty {
    color: var(--qa-text-muted);
    padding: 36px 0;
    text-align: center;
    font-size: 14.5px;
}

.qa-item {
    border-bottom: 1px solid var(--qa-border-light);
    transition: var(--qa-transition);
    border-radius: var(--qa-radius-sm);
}
.qa-item:last-child { border-bottom: none; }
.qa-item[open] {
    background: var(--qa-primary-bg);
    margin: 6px -14px;
    padding: 0 14px;
    box-shadow: var(--qa-shadow-xs);
}

.qa-q {
    cursor: pointer;
    padding: 18px 6px;
    font-size: 16.5px;
    font-weight: 600;
    color: var(--qa-text);
    list-style: none;
    display: flex;
    align-items: center;
    gap: 14px;
    transition: var(--qa-transition-fast);
    user-select: none;
    -webkit-tap-highlight-color: transparent;
    line-height: 1.5;
}
.qa-q::-webkit-details-marker { display: none; }
.qa-q::before {
    content: "Q";
    flex-shrink: 0;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 30px;
    height: 30px;
    background: linear-gradient(135deg, var(--qa-primary) 0%, var(--qa-accent) 100%);
    color: #fff;
    border-radius: 9px;
    font-size: 14px;
    font-weight: 800;
    box-shadow: 0 2px 8px rgba(37,99,235,0.25);
    transition: var(--qa-transition);
}
.qa-q::after {
    content: "";
    flex-shrink: 0;
    margin-left: auto;
    width: 22px;
    height: 22px;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='22' height='22' viewBox='0 0 24 24' fill='none' stroke='%2394a3b8' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: center;
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}
.qa-item[open] .qa-q {
    color: var(--qa-primary-dark);
}
.qa-item[open] .qa-q::before {
    transform: rotate(-5deg) scale(1.05);
    box-shadow: 0 4px 12px rgba(37,99,235,0.35);
}
.qa-item[open] .qa-q::after {
    transform: rotate(180deg);
}
.qa-q:hover {
    color: var(--qa-primary);
}
.qa-q h2 {
    margin: 0;
    font-size: inherit;
    font-weight: inherit;
    line-height: inherit;
}

.qa-a {
    padding: 6px 6px 24px 44px;
    color: var(--qa-text-secondary);
    font-size: 15.5px;
    line-height: 1.9;
    animation: qaFadeIn 0.35s ease-out;
}
.qa-a p { margin: 0 0 14px; }
.qa-a p:last-child { margin-bottom: 0; }
.qa-a strong {
    color: var(--qa-text);
    font-weight: 600;
}
.qa-a ul, .qa-a ol {
    margin: 0 0 14px;
    padding-left: 22px;
}
.qa-a li { margin-bottom: 6px; }
.qa-a code {
    background: var(--qa-bg-alt);
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 13.5px;
    color: var(--qa-primary-dark);
    font-family: "SF Mono", Monaco, "Cascadia Code", "Roboto Mono", Consolas, monospace;
}

@keyframes qaFadeIn {
    from { opacity: 0; transform: translateY(-8px); }
    to { opacity: 1; transform: translateY(0); }
}

.qa-related {
    background: var(--qa-surface);
    border: 1px solid var(--qa-border);
    border-radius: var(--qa-radius-lg);
    padding: 28px 32px;
    box-shadow: var(--qa-shadow-sm);
}
.qa-related h2 {
    font-size: 19px;
    margin: 0 0 18px;
    color: var(--qa-text);
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 12px;
    letter-spacing: -0.01em;
}
.qa-related h2::before {
    content: "";
    display: inline-block;
    width: 5px;
    height: 20px;
    background: linear-gradient(180deg, var(--qa-primary) 0%, var(--qa-accent) 100%);
    border-radius: 3px;
}
.qa-related ul {
    margin: 0;
    padding: 0;
    list-style: none;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 4px 16px;
}
.qa-related li {
    margin: 0;
    padding: 0;
}
.qa-related a {
    color: var(--qa-text-secondary);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 14.5px;
    padding: 10px 12px;
    border-radius: var(--qa-radius-sm);
    transition: var(--qa-transition-fast);
    line-height: 1.5;
}
.qa-related a::before {
    content: "";
    flex-shrink: 0;
    width: 6px;
    height: 6px;
    background: var(--qa-primary);
    border-radius: 50%;
    opacity: 0.5;
    transition: var(--qa-transition-fast);
}
.qa-related a:hover {
    color: var(--qa-primary);
    background: var(--qa-primary-bg);
    padding-left: 16px;
}
.qa-related a:hover::before {
    opacity: 1;
    transform: scale(1.3);
}

.qa-footer {
    text-align: center;
    color: var(--qa-text-muted);
    padding: 32px 20px 40px;
    font-size: 13.5px;
    border-top: 1px solid var(--qa-border);
    background: var(--qa-surface);
}
.qa-footer a {
    color: var(--qa-text-secondary);
}
.qa-footer a:hover {
    color: var(--qa-primary);
}

.qa-empty-state {
    text-align: center;
    padding: 56px 20px;
    color: var(--qa-text-muted);
}
.qa-empty-state-icon {
    font-size: 52px;
    margin-bottom: 16px;
    opacity: 0.4;
}
.qa-empty-state-text {
    font-size: 15px;
    margin-bottom: 8px;
}
.qa-empty-state-hint {
    font-size: 13.5px;
    color: var(--qa-text-muted);
}

.qa-stats-bar {
    display: flex;
    align-items: center;
    gap: 24px;
    padding: 16px 24px;
    background: linear-gradient(135deg, var(--qa-primary-bg) 0%, #f0f9ff 100%);
    border-radius: var(--qa-radius);
    margin-bottom: 24px;
    border: 1px solid rgba(37,99,235,0.1);
}
.qa-stat-item {
    display: flex;
    flex-direction: column;
    gap: 2px;
}
.qa-stat-number {
    font-size: 24px;
    font-weight: 700;
    color: var(--qa-primary);
    line-height: 1.2;
}
.qa-stat-label {
    font-size: 12.5px;
    color: var(--qa-text-secondary);
}
.qa-stat-divider {
    width: 1px;
    height: 36px;
    background: var(--qa-border);
}

.qa-back-to-top {
    position: fixed;
    bottom: 32px;
    right: 32px;
    width: 44px;
    height: 44px;
    background: var(--qa-surface);
    border: 1px solid var(--qa-border);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    box-shadow: var(--qa-shadow-md);
    transition: var(--qa-transition);
    opacity: 0;
    visibility: hidden;
    transform: translateY(10px);
    z-index: 90;
    color: var(--qa-text-secondary);
}
.qa-back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}
.qa-back-to-top:hover {
    background: var(--qa-primary);
    color: #fff;
    border-color: var(--qa-primary);
    box-shadow: var(--qa-shadow-primary-lg);
    transform: translateY(-2px);
}

@media (min-width: 1280px) {
    :root {
        --qa-max-width: 1160px;
    }
    .qa-cards {
        gap: 18px;
    }
}

@media (max-width: 900px) {
    :root {
        --qa-content-padding: 18px;
        --qa-header-height: 58px;
    }
    .qa-container { padding: 0 var(--qa-content-padding); }
    .qa-header-inner { padding: 0 var(--qa-content-padding); }

    .qa-main { padding: 28px 0 44px; }

    .qa-page-title h1 { font-size: 26px; }
    .qa-page-sub { font-size: 14.5px; }

    .qa-body { padding: 6px 22px; }

    .qa-cat { padding: 20px 0; }
    .qa-cat-title { font-size: 18px; margin-bottom: 16px; }

    .qa-cards {
        grid-template-columns: 1fr;
        gap: 12px;
    }
    .qa-card { padding: 18px 20px; }

    .qa-article { padding: 30px 26px; }
    .qa-article h1 { font-size: 25px; }

    .qa-related { padding: 22px 24px; }
    .qa-related ul {
        grid-template-columns: 1fr;
        gap: 2px;
    }

    .qa-stats-bar {
        gap: 16px;
        padding: 14px 18px;
        flex-wrap: wrap;
    }
    .qa-stat-number { font-size: 20px; }
    .qa-stat-divider { display: none; }
}

@media (max-width: 640px) {
    :root {
        --qa-content-padding: 14px;
        --qa-header-height: 54px;
        --qa-radius-lg: 14px;
    }

    .qa-main { padding: 20px 0 36px; }

    
    .qa-header-inner {
        padding: 0 var(--qa-content-padding);
        flex-direction: column;
        align-items: flex-start;
        justify-content: center;
        gap: 6px;
        height: auto;
        padding-top: 10px;
        padding-bottom: 10px;
    }
    .qa-logo a {
        font-size: 18px;
        padding-left: 36px;
        min-height: 28px;
    }
    .qa-logo a::before {
        width: 28px;
        height: 28px;
        font-size: 14px;
        border-radius: 8px;
    }
    .qa-nav {
        width: 100%;
        overflow-x: auto;
        -webkit-overflow-scrolling: touch;
        scrollbar-width: none;
    }
    .qa-nav::-webkit-scrollbar { display: none; }
    .qa-nav ul {
        gap: 2px;
        width: max-content;
    }
    .qa-nav a {
        padding: 6px 12px;
        font-size: 13.5px;
        white-space: nowrap;
    }

    
    .qa-page-title { margin-bottom: 20px; }
    .qa-page-title h1 { font-size: 23px; margin-bottom: 8px; }
    .qa-page-sub { font-size: 14px; }

    
    .qa-body {
        padding: 4px 16px;
        border-radius: var(--qa-radius);
    }

    
    .qa-cat { padding: 18px 0; }
    .qa-cat-title {
        font-size: 17px;
        margin-bottom: 14px;
        gap: 10px;
    }
    .qa-cat-title::before {
        width: 4px;
        height: 18px;
    }

    
    .qa-cards { gap: 10px; }
    .qa-card {
        padding: 16px 18px;
        border-radius: var(--qa-radius-sm);
    }
    .qa-card-title { font-size: 15px; margin-bottom: 8px; }
    .qa-card-desc { font-size: 13px; margin-bottom: 12px; }
    .qa-card-count {
        font-size: 12px;
        padding: 4px 12px;
    }
    .qa-card-arrow { display: none; }

    
    .qa-article {
        padding: 22px 18px;
        border-radius: var(--qa-radius);
        margin-bottom: 20px;
    }
    .qa-article h1 { font-size: 21px; margin-bottom: 12px; }

    .qa-meta {
        font-size: 12.5px;
        gap: 6px 12px;
        margin-bottom: 20px;
        padding-bottom: 16px;
    }

    .qa-intro {
        padding: 14px 16px;
        font-size: 14px;
        margin-bottom: 22px;
    }

    
    .qa-q {
        padding: 16px 4px;
        font-size: 15.5px;
        gap: 10px;
        min-height: 48px;
    }
    .qa-q::before {
        width: 26px;
        height: 26px;
        font-size: 12.5px;
        border-radius: 7px;
    }
    .qa-q::after {
        width: 20px;
        height: 20px;
    }
    .qa-a {
        padding: 4px 4px 20px 36px;
        font-size: 14.5px;
        line-height: 1.85;
    }
    .qa-item[open] {
        margin: 4px -10px;
        padding: 0 10px;
    }

    
    .qa-related {
        padding: 20px 18px;
        border-radius: var(--qa-radius);
    }
    .qa-related h2 { font-size: 17px; margin-bottom: 14px; }
    .qa-related a {
        font-size: 14px;
        padding: 9px 10px;
    }

    
    .qa-footer {
        padding: 24px 16px 32px;
        font-size: 12.5px;
    }

    
    .qa-stats-bar {
        gap: 12px;
        padding: 12px 16px;
        margin-bottom: 18px;
    }
    .qa-stat-number { font-size: 18px; }
    .qa-stat-label { font-size: 12px; }

    
    .qa-back-to-top {
        bottom: 20px;
        right: 20px;
        width: 40px;
        height: 40px;
    }

    
    .qa-breadcrumb {
        font-size: 12.5px;
        margin-bottom: 14px;
        gap: 6px;
    }
}

@media (max-width: 380px) {
    :root {
        --qa-content-padding: 12px;
    }
    .qa-page-title h1 { font-size: 20px; }
    .qa-article h1 { font-size: 19px; }
    .qa-nav a { padding: 5px 10px; font-size: 12.5px; }
    .qa-card { padding: 14px 16px; }
    .qa-card-title { font-size: 14.5px; }
    .qa-q { font-size: 14.5px; }
    .qa-a { font-size: 14px; }
}

@media (prefers-color-scheme: dark) {
    :root {
        --qa-bg: #0b1220;
        --qa-bg-alt: #111827;
        --qa-surface: #151e2e;
        --qa-surface-hover: #1a2538;
        --qa-border: #2a3648;
        --qa-border-light: #1f2a3c;
        --qa-border-hover: #3b4a60;
        --qa-text: #f1f5f9;
        --qa-text-secondary: #cbd5e1;
        --qa-text-muted: #8b9bb4;
        --qa-primary-bg: #162544;
        --qa-primary-bg-hover: #1e3a5f;
        --qa-shadow-sm: 0 1px 3px rgba(0,0,0,0.3);
        --qa-shadow: 0 2px 8px rgba(0,0,0,0.35);
        --qa-shadow-md: 0 4px 16px rgba(0,0,0,0.4);
        --qa-shadow-lg: 0 12px 32px rgba(0,0,0,0.5);
        --qa-shadow-primary: 0 4px 14px rgba(37,99,235,0.35);
        --qa-shadow-primary-lg: 0 8px 24px rgba(37,99,235,0.45);
    }

    .qa-header {
        background-color: rgba(21, 30, 46, 0.85);
        background-image: none;
    }
    .qa-header.scrolled {
        background: rgba(21, 30, 46, 0.92);
    }

    .qa-logo a { color: var(--qa-text); }
    .qa-logo a:hover { color: var(--qa-primary-light); }

    .qa-card { background: var(--qa-surface); }
    .qa-card:hover { background: var(--qa-surface-hover); }

    .qa-intro {
        background: linear-gradient(135deg, #162544 0%, #0c2d44 100%);
        border-left-color: var(--qa-primary-light);
    }
    .qa-intro::before {
        background: radial-gradient(circle at top right, rgba(14,165,233,0.12), transparent 70%);
    }

    .qa-item[open] {
        background: var(--qa-primary-bg);
    }

    .qa-stats-bar {
        background: linear-gradient(135deg, #162544 0%, #0c2d44 100%);
        border-color: rgba(59,130,246,0.2);
    }

    .qa-a code {
        background: var(--qa-bg-alt);
        color: var(--qa-accent-light);
    }

    .qa-back-to-top {
        background: var(--qa-surface);
        border-color: var(--qa-border);
        color: var(--qa-text-secondary);
    }
    .qa-back-to-top:hover {
        background: var(--qa-primary);
        color: #fff;
    }
}

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
    .qa-card:hover { transform: none; }
}

.qa-nav a:focus-visible,
.qa-card a:focus-visible,
.qa-related a:focus-visible,
.qa-q:focus-visible,
.qa-back-to-top:focus-visible {
    outline: 2px solid var(--qa-primary);
    outline-offset: 2px;
    border-radius: var(--qa-radius-sm);
}

::selection {
    background: rgba(37, 99, 235, 0.2);
    color: var(--qa-text);
}

@media (min-width: 641px) {
    .zk-qa ::-webkit-scrollbar {
        width: 8px;
        height: 8px;
    }
    .zk-qa ::-webkit-scrollbar-track {
        background: transparent;
    }
    .zk-qa ::-webkit-scrollbar-thumb {
        background: var(--qa-border-hover);
        border-radius: 4px;
    }
    .zk-qa ::-webkit-scrollbar-thumb:hover {
        background: var(--qa-text-muted);
    }
}