/* ===== 全局重置与基础样式 ===== */
*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary: #1e3a5f;
    --primary-light: #2a5a8f;
    --primary-dark: #0f1f33;
    --accent: #f0b429;
    --accent-hover: #d49a1f;
    --text-primary: #1a1f2b;
    --text-secondary: #4a5568;
    --text-light: #718096;
    --bg-primary: #ffffff;
    --bg-secondary: #f7f8fc;
    --bg-card: #ffffff;
    --bg-glass: rgba(255, 255, 255, 0.7);
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.12);
    --shadow-glass: 0 8px 32px rgba(0, 0, 0, 0.1);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --radius-xl: 28px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --font-sans: 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', system-ui, -apple-system, sans-serif;
    --max-width: 1200px;
    --header-height: 70px;
    --gradient-hero: linear-gradient(135deg, #0f1f33 0%, #1e3a5f 40%, #2a5a8f 70%, #1e3a5f 100%);
    --gradient-card: linear-gradient(145deg, #ffffff, #f0f4ff);
    --gradient-glass: linear-gradient(135deg, rgba(255,255,255,0.9), rgba(255,255,255,0.4));
    --nav-blur: 12px;
}

/* 暗色模式 */
[data-theme="dark"] {
    --primary: #2a5a8f;
    --primary-light: #3a7acf;
    --primary-dark: #0a1525;
    --accent: #f0b429;
    --accent-hover: #ffc94d;
    --text-primary: #e8edf5;
    --text-secondary: #b0c4de;
    --text-light: #8899aa;
    --bg-primary: #0f1f33;
    --bg-secondary: #1a2a44;
    --bg-card: #1e3050;
    --bg-glass: rgba(30, 48, 80, 0.8);
    --border-color: #2a4060;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.5);
    --shadow-glass: 0 8px 32px rgba(0, 0, 0, 0.4);
    --gradient-card: linear-gradient(145deg, #1e3050, #152540);
    --gradient-glass: linear-gradient(135deg, rgba(30,48,80,0.9), rgba(30,48,80,0.5));
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-sans);
    color: var(--text-primary);
    background: var(--bg-primary);
    line-height: 1.7;
    overflow-x: hidden;
    transition: background 0.4s ease, color 0.4s ease;
    -webkit-font-smoothing: antialiased;
}

a {
    color: var(--primary-light);
    text-decoration: none;
    transition: var(--transition);
}

a:hover {
    color: var(--accent);
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 24px;
}

section {
    padding: 100px 0;
    position: relative;
}

h1, h2, h3, h4 {
    line-height: 1.3;
    font-weight: 700;
}

/* ===== 滚动动画 (Intersection Observer 配合) ===== */
.fade-in-up {
    opacity: 0;
    transform: translateY(40px);
    transition: opacity 0.8s ease, transform 0.8s ease;
}

.fade-in-up.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ===== 头部导航 ===== */
header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: var(--bg-glass);
    backdrop-filter: blur(var(--nav-blur));
    -webkit-backdrop-filter: blur(var(--nav-blur));
    border-bottom: 1px solid var(--border-color);
    transition: var(--transition);
    height: var(--header-height);
}

header.scrolled {
    background: var(--bg-glass);
    box-shadow: var(--shadow-md);
}

.nav-inner {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: var(--header-height);
}

.logo {
    display: flex;
    align-items: center;
    flex-shrink: 0;
    transition: var(--transition);
}

.logo:hover {
    opacity: 0.85;
    transform: scale(1.02);
}

.logo svg {
    display: block;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 8px;
    align-items: center;
}

.nav-links a {
    display: block;
    padding: 8px 18px;
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 0.95rem;
    transition: var(--transition);
    position: relative;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: 2px;
    left: 18px;
    right: 18px;
    height: 2px;
    background: var(--accent);
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

.nav-links a:hover {
    color: var(--text-primary);
    background: rgba(240, 180, 41, 0.08);
}

.nav-links a:hover::after {
    transform: scaleX(1);
}

.dark-mode-toggle {
    background: none;
    border: 2px solid var(--border-color);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    font-size: 1.2rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
    color: var(--text-primary);
    background: var(--bg-card);
    margin-left: 8px;
}

.dark-mode-toggle:hover {
    border-color: var(--accent);
    background: var(--accent);
    color: #fff;
    transform: rotate(15deg);
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    font-size: 1.8rem;
    cursor: pointer;
    color: var(--text-primary);
    padding: 4px 8px;
    transition: var(--transition);
    border-radius: var(--radius-sm);
}

.mobile-menu-btn:hover {
    background: rgba(240, 180, 41, 0.1);
}

/* ===== Hero 区域 ===== */
#hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient-hero);
    position: relative;
    overflow: hidden;
    padding-top: var(--header-height);
}

#hero::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle at 30% 50%, rgba(240, 180, 41, 0.08) 0%, transparent 60%),
                radial-gradient(circle at 70% 80%, rgba(42, 90, 143, 0.15) 0%, transparent 50%);
    animation: heroGlow 15s ease-in-out infinite alternate;
    pointer-events: none;
}

@keyframes heroGlow {
    0% { transform: translate(0, 0) rotate(0deg); }
    100% { transform: translate(-5%, -5%) rotate(3deg); }
}

#hero::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 150px;
    background: linear-gradient(to top, var(--bg-primary), transparent);
    pointer-events: none;
}

.hero-content {
    text-align: center;
    max-width: 800px;
    padding: 0 24px;
    position: relative;
    z-index: 2;
    animation: heroIn 1.2s ease forwards;
}

@keyframes heroIn {
    0% { opacity: 0; transform: translateY(30px); }
    100% { opacity: 1; transform: translateY(0); }
}

.hero-content h1 {
    font-size: clamp(2.2rem, 6vw, 4rem);
    font-weight: 800;
    color: #ffffff;
    margin-bottom: 24px;
    letter-spacing: -0.02em;
    text-shadow: 0 2px 20px rgba(0, 0, 0, 0.3);
}

.hero-content p {
    font-size: clamp(1rem, 2vw, 1.25rem);
    color: rgba(255, 255, 255, 0.85);
    margin-bottom: 36px;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
    line-height: 1.8;
}

.btn-primary {
    display: inline-block;
    padding: 16px 48px;
    background: var(--accent);
    color: #1a1f2b;
    font-weight: 700;
    font-size: 1.1rem;
    border-radius: 50px;
    transition: var(--transition);
    box-shadow: 0 4px 20px rgba(240, 180, 41, 0.4);
    border: none;
    cursor: pointer;
    text-decoration: none;
}

.btn-primary:hover {
    background: var(--accent-hover);
    transform: translateY(-3px) scale(1.02);
    box-shadow: 0 8px 30px rgba(240, 180, 41, 0.5);
    color: #1a1f2b;
}

/* ===== 通用标题 ===== */
section h2 {
    font-size: clamp(1.8rem, 4vw, 2.8rem);
    text-align: center;
    margin-bottom: 60px;
    position: relative;
    color: var(--text-primary);
}

section h2::after {
    content: '';
    display: block;
    width: 60px;
    height: 4px;
    background: var(--accent);
    border-radius: 2px;
    margin: 16px auto 0;
}

/* ===== About 区域 ===== */
#about {
    background: var(--bg-secondary);
}

.about-grid {
    display: grid;
    grid-template-columns: 1.2fr 1fr;
    gap: 60px;
    align-items: center;
}

.about-text p {
    margin-bottom: 20px;
    color: var(--text-secondary);
    font-size: 1.05rem;
    line-height: 1.8;
}

.about-text strong {
    color: var(--text-primary);
}

.about-highlights {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
}

.highlight-card {
    background: var(--gradient-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 28px 20px;
    text-align: center;
    transition: var(--transition);
    box-shadow: var(--shadow-sm);
    backdrop-filter: blur(6px);
}

.highlight-card:hover {
    transform: translateY(-6px) scale(1.02);
    box-shadow: var(--shadow-lg);
    border-color: var(--accent);
}

.highlight-icon {
    font-size: 2.4rem;
    display: block;
    margin-bottom: 12px;
}

.highlight-card span:last-child {
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.95rem;
}

/* ===== Services 区域 ===== */
.services-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 28px;
}

.service-card {
    background: var(--gradient-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 36px 28px;
    transition: var(--transition);
    box-shadow: var(--shadow-sm);
    position: relative;
    overflow: hidden;
}

.service-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--accent);
    transform: scaleX(0);
    transition: transform 0.4s ease;
    transform-origin: left;
}

.service-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg);
    border-color: var(--accent);
}

.service-card:hover::before {
    transform: scaleX(1);
}

.service-card h3 {
    font-size: 1.35rem;
    margin-bottom: 16px;
    color: var(--text-primary);
}

.service-card p {
    color: var(--text-secondary);
    line-height: 1.7;
}

/* ===== Features 区域 ===== */
#features {
    background: var(--bg-secondary);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 28px;
}

.feature-item {
    background: var(--gradient-glass);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 32px 24px;
    text-align: center;
    transition: var(--transition);
    box-shadow: var(--shadow-glass);
}

.feature-item:hover {
    transform: translateY(-6px) scale(1.02);
    box-shadow: var(--shadow-lg);
    border-color: var(--accent);
}

.feature-item h3 {
    font-size: 1.2rem;
    margin-bottom: 14px;
    color: var(--text-primary);
}

.feature-item p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.7;
}

/* ===== Testimonials 区域 ===== */
.testimonials-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 28px;
}

.testimonials-grid blockquote {
    background: var(--gradient-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 32px 28px;
    position: relative;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.testimonials-grid blockquote:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    border-color: var(--accent);
}

.testimonials-grid blockquote::before {
    content: '"';
    font-size: 4rem;
    color: var(--accent);
    position: absolute;
    top: 8px;
    left: 20px;
    opacity: 0.3;
    font-family: Georgia, serif;
    line-height: 1;
}

.testimonials-grid blockquote p {
    font-style: italic;
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 16px;
    position: relative;
    z-index: 1;
}

.testimonials-grid blockquote footer {
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.9rem;
}

/* ===== Knowledge 区域 ===== */
#knowledge {
    background: var(--bg-secondary);
}

.knowledge-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
}

.knowledge-card {
    background: var(--gradient-glass);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 28px 22px;
    transition: var(--transition);
    box-shadow: var(--shadow-glass);
}

.knowledge-card:hover {
    transform: translateY(-6px) scale(1.02);
    box-shadow: var(--shadow-lg);
    border-color: var(--accent);
}

.knowledge-card h3 {
    font-size: 1.1rem;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.knowledge-card p {
    color: var(--text-secondary);
    font-size: 0.92rem;
    line-height: 1.7;
    margin-bottom: 16px;
}

.knowledge-card a {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-weight: 600;
    color: var(--primary-light);
    font-size: 0.9rem;
    transition: var(--transition);
}

.knowledge-card a::after {
    content: '→';
    transition: transform 0.3s ease;
}

.knowledge-card a:hover {
    color: var(--accent);
}

.knowledge-card a:hover::after {
    transform: translateX(4px);
}

/* ===== HowTo 区域 ===== */
#howto {
    background: var(--bg-primary);
}

.howto-steps {
    max-width: 700px;
    margin: 0 auto;
    list-style: none;
    counter-reset: step-counter;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.howto-steps li {
    counter-increment: step-counter;
    padding: 20px 28px 20px 64px;
    background: var(--gradient-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    position: relative;
    transition: var(--transition);
    box-shadow: var(--shadow-sm);
    color: var(--text-secondary);
    line-height: 1.7;
}

.howto-steps li::before {
    content: counter(step-counter);
    position: absolute;
    left: 20px;
    top: 50%;
    transform: translateY(-50%);
    width: 32px;
    height: 32px;
    background: var(--accent);
    color: #1a1f2b;
    font-weight: 700;
    font-size: 0.95rem;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.howto-steps li:hover {
    transform: translateX(6px);
    box-shadow: var(--shadow-md);
    border-color: var(--accent);
}

.howto-steps li strong {
    color: var(--text-primary);
}

/* ===== FAQ 区域 ===== */
#faq {
    background: var(--bg-secondary);
}

.faq-list {
    max-width: 800px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.faq-list details {
    background: var(--gradient-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 0;
    overflow: hidden;
    transition: var(--transition);
    box-shadow: var(--shadow-sm);
}

.faq-list details:hover {
    border-color: var(--accent);
    box-shadow: var(--shadow-md);
}

.faq-list details[open] {
    border-color: var(--accent);
    box-shadow: var(--shadow-md);
}

.faq-list summary {
    padding: 20px 28px;
    font-weight: 600;
    font-size: 1.05rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: space-between;
    color: var(--text-primary);
    transition: var(--transition);
    list-style: none;
}

.faq-list summary::-webkit-details-marker {
    display: none;
}

.faq-list summary::after {
    content: '+';
    font-size: 1.6rem;
    font-weight: 300;
    transition: transform 0.3s ease;
    color: var(--accent);
    line-height: 1;
}

.faq-list details[open] summary::after {
    transform: rotate(45deg);
}

.faq-list details p {
    padding: 0 28px 20px 28px;
    color: var(--text-secondary);
    line-height: 1.8;
}

/* ===== Contact 区域 ===== */
#contact {
    background: var(--bg-primary);
}

.contact-info {
    max-width: 600px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 16px;
    padding: 40px;
    background: var(--gradient-glass);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-glass);
    transition: var(--transition);
}

.contact-info:hover {
    border-color: var(--accent);
    box-shadow: var(--shadow-lg);
}

.contact-info p {
    font-size: 1.05rem;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    gap: 12px;
}

.contact-info strong {
    color: var(--text-primary);
    min-width: 120px;
}

/* ===== Footer ===== */
footer {
    background: var(--primary-dark);
    color: rgba(255, 255, 255, 0.8);
    padding: 48px 24px 32px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-inner {
    max-width: var(--max-width);
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 24px;
}

.footer-links {
    display: flex;
    flex-wrap: wrap;
    gap: 8px 24px;
    justify-content: center;
}

.footer-links a {
    color: rgba(255, 255, 255, 0.7);
    font-size: 0.95rem;
    padding: 4px 8px;
    border-radius: var(--radius-sm);
    transition: var(--transition);
}

.footer-links a:hover {
    color: var(--accent);
    background: rgba(240, 180, 41, 0.1);
}

.footer-copyright {
    text-align: center;
    font-size: 0.9rem;
    color: rgba(255, 255, 255, 0.5);
    line-height: 1.8;
}

/* ===== 返回顶部 ===== */
#back-to-top {
    position: fixed;
    bottom: 32px;
    right: 32px;
    width: 48px;
    height: 48px;
    background: var(--accent);
    color: #1a1f2b;
    border: none;
    border-radius: 50%;
    font-size: 1.4rem;
    cursor: pointer;
    box-shadow: var(--shadow-md);
    transition: var(--transition);
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    z-index: 999;
    display: flex;
    align-items: center;
    justify-content: center;
}

#back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

#back-to-top:hover {
    background: var(--accent-hover);
    transform: translateY(-4px) scale(1.1);
    box-shadow: var(--shadow-lg);
}

/* ===== 响应式设计 ===== */

/* 平板 (≤1024px) */
@media (max-width: 1024px) {
    .about-grid {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .services-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .features-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .testimonials-grid {
        grid-template-columns: 1fr;
        max-width: 600px;
        margin: 0 auto;
    }

    .knowledge-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    section {
        padding: 80px 0;
    }

    .nav-links {
        gap: 4px;
    }

    .nav-links a {
        padding: 6px 14px;
        font-size: 0.9rem;
    }
}

/* 手机 (≤768px) */
@media (max-width: 768px) {
    :root {
        --header-height: 60px;
    }

    .nav-links {
        display: none;
        position: absolute;
        top: var(--header-height);
        left: 0;
        right: 0;
        background: var(--bg-glass);
        backdrop-filter: blur(20px);
        -webkit-backdrop-filter: blur(20px);
        flex-direction: column;
        padding: 16px 24px;
        border-bottom: 1px solid var(--border-color);
        box-shadow: var(--shadow-lg);
        gap: 4px;
    }

    .nav-links.open {
        display: flex;
    }

    .nav-links a {
        padding: 12px 16px;
        font-size: 1rem;
        width: 100%;
        text-align: center;
    }

    .nav-links a::after {
        display: none;
    }

    .mobile-menu-btn {
        display: block;
    }

    .dark-mode-toggle {
        width: 36px;
        height: 36px;
        font-size: 1rem;
    }

    #hero {
        min-height: 90vh;
    }

    .hero-content h1 {
        font-size: 2rem;
    }

    .hero-content p {
        font-size: 1rem;
    }

    .btn-primary {
        padding: 14px 36px;
        font-size: 1rem;
    }

    section {
        padding: 60px 0;
    }

    section h2 {
        font-size: 1.8rem;
        margin-bottom: 40px;
    }

    .about-grid {
        grid-template-columns: 1fr;
        gap: 32px;
    }

    .about-highlights {
        grid-template-columns: 1fr 1fr;
        gap: 16px;
    }

    .services-grid {
        grid-template-columns: 1fr;
        max-width: 500px;
        margin: 0 auto;
    }

    .features-grid {
        grid-template-columns: 1fr 1fr;
        gap: 16px;
    }

    .testimonials-grid {
        grid-template-columns: 1fr;
    }

    .knowledge-grid {
        grid-template-columns: 1fr;
        max-width: 500px;
        margin: 0 auto;
    }

    .howto-steps li {
        padding: 16px 20px 16px 52px;
    }

    .howto-steps li::before {
        left: 14px;
        width: 28px;
        height: 28px;
        font-size: 0.85rem;
    }

    .contact-info {
        padding: 24px 20px;
    }

    .contact-info p {
        flex-direction: column;
        align-items: flex-start;
        gap: 4px;
    }

    .contact-info strong {
        min-width: auto;
    }

    #back-to-top {
        bottom: 20px;
        right: 20px;
        width: 42px;
        height: 42px;
        font-size: 1.2rem;
    }

    .footer-links {
        gap: 4px 16px;
    }

    .container {
        padding: 0 16px;
    }
}

/* 小手机 (≤480px) */
@media (max-width: 480px) {
    .hero-content h1 {
        font-size: 1.7rem;
    }

    .about-highlights {
        grid-template-columns: 1fr;
    }

    .features-grid {
        grid-template-columns: 1fr;
        max-width: 400px;
        margin: 0 auto;
    }

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

    .service-card {
        padding: 28px 20px;
    }

    .knowledge-card {
        padding: 22px 18px;
    }

    .faq-list summary {
        padding: 16px 20px;
        font-size: 0.95rem;
    }

    .faq-list details p {
        padding: 0 20px 16px 20px;
    }
}

/* ===== 暗色模式切换过渡 ===== */
body, header, .nav-inner, .hero-content, section, footer, .container, 
.service-card, .feature-item, .knowledge-card, .highlight-card, 
.testimonials-grid blockquote, .faq-list details, .contact-info,
.howto-steps li, .btn-primary, .dark-mode-toggle, #back-to-top {
    transition: background 0.4s ease, color 0.4s ease, border-color 0.4s ease, box-shadow 0.4s ease;
}

/* ===== 滚动条美化 ===== */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
    background: var(--primary-light);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--accent);
}

/* ===== 选中文本样式 ===== */
::selection {
    background: var(--accent);
    color: #1a1f2b;
}

/* ===== 焦点样式 ===== */
:focus-visible {
    outline: 3px solid var(--accent);
    outline-offset: 2px;
    border-radius: 4px;
}

/* ===== 打印样式 ===== */
@media print {
    header, #back-to-top, .mobile-menu-btn, .dark-mode-toggle {
        display: none !important;
    }
    body {
        background: #fff;
        color: #000;
    }
    section {
        padding: 20px 0;
        page-break-inside: avoid;
    }
}