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

:root {
    --color-deep-blue: #0f1b3d;
    --color-burgundy: #8c1c13;
    --color-gold: #c9a85c;
    --color-white: #ffffff;
    --color-light-gray: #f5f6f8;
    --color-medium-gray: #6c757d;
    --color-dark-gray: #343a40;
    --max-width: 1180px;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei", Arial, sans-serif;
    color: var(--color-dark-gray);
    line-height: 1.6;
    background-color: var(--color-white);
}

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
.header {
    position: sticky;
    top: 0;
    background: var(--color-white);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
    z-index: 1000;
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
    color: var(--color-deep-blue);
    font-size: 20px;
    font-weight: 600;
}

.logo-img {
    height: 40px;
    width: auto;
    object-fit: contain;
}

.nav {
    display: flex;
    align-items: center;
    gap: 32px;
}

.nav-list {
    display: flex;
    list-style: none;
    gap: 32px;
}

.nav-link {
    text-decoration: none;
    color: var(--color-dark-gray);
    font-size: 15px;
    font-weight: 500;
    transition: color 0.3s ease;
}

.nav-link:hover {
    color: var(--color-burgundy);
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 28px;
    border-radius: 6px;
    font-size: 15px;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.3s ease;
    cursor: pointer;
    border: none;
}

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

.btn-primary:hover {
    background: #721710;
}

.btn-secondary {
    background: transparent;
    color: var(--color-deep-blue);
    border: 2px solid var(--color-deep-blue);
}

.btn-secondary:hover {
    background: var(--color-deep-blue);
    color: var(--color-white);
}

.btn-gold {
    background: var(--color-gold);
    color: var(--color-deep-blue);
}

.btn-gold:hover {
    background: #b8984c;
}

/* Mobile Menu */
.mobile-menu-btn {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: transparent;
    border: none;
    cursor: pointer;
    padding: 8px;
}

.mobile-menu-btn span {
    width: 25px;
    height: 3px;
    background: var(--color-deep-blue);
    border-radius: 2px;
    transition: all 0.3s ease;
}

.mobile-menu-btn.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.mobile-menu-btn.active span:nth-child(2) {
    opacity: 0;
}

.mobile-menu-btn.active span:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -7px);
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--color-deep-blue) 0%, #1a2d5a 100%);
    color: var(--color-white);
    padding: 80px 0;
}

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

.hero-content h1 {
    font-size: 36px;
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 20px;
}

.hero-content p {
    font-size: 16px;
    line-height: 1.8;
    opacity: 0.9;
    margin-bottom: 32px;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

.hero-image img {
    width: 100%;
    height: auto;
    object-fit: cover;
    border-radius: 12px;
}

.hero-features {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
    margin-top: 48px;
    padding-top: 32px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.hero-feature {
    text-align: center;
}

.hero-feature-icon {
    font-size: 28px;
    margin-bottom: 8px;
}

.hero-feature-text {
    font-size: 14px;
    opacity: 0.9;
}

/* Section */
.section {
    padding: 70px 0;
}

.section-alt {
    background: var(--color-light-gray);
}

.section-header {
    text-align: center;
    margin-bottom: 48px;
}

.section-header h2 {
    font-size: 30px;
    color: var(--color-deep-blue);
    margin-bottom: 16px;
}

.section-header p {
    color: var(--color-medium-gray);
    font-size: 16px;
    max-width: 700px;
    margin: 0 auto;
}

/* Cards */
.cards-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 28px;
}

.card {
    background: var(--color-white);
    border-radius: 10px;
    padding: 32px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.06);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.12);
}

.card-icon {
    font-size: 36px;
    margin-bottom: 20px;
}

.card h3 {
    font-size: 20px;
    color: var(--color-deep-blue);
    margin-bottom: 12px;
}

.card p {
    color: var(--color-medium-gray);
    font-size: 15px;
    margin-bottom: 20px;
}

/* Feature Blocks */
.feature-block {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}

.feature-block-reverse {
    direction: rtl;
}

.feature-block-reverse > * {
    direction: ltr;
}

.feature-content h3 {
    font-size: 26px;
    color: var(--color-deep-blue);
    margin-bottom: 20px;
}

.feature-content p {
    color: var(--color-medium-gray);
    font-size: 15px;
    line-height: 1.8;
    margin-bottom: 24px;
}

/* Feature 图片：固定视觉高度，但不裁切图片 */
.feature-image {
    width: 100%;
    min-height: 320px;
    border-radius: 10px;
    overflow: hidden;
    background: #050816;
    display: flex;
    align-items: center;
    justify-content: center;
}

.feature-image img {
    width: 100%;
    height: 320px;
    object-fit: contain;
    object-position: center center;
    border-radius: 10px;
    display: block;
}

@media (max-width: 768px) {
    .feature-image {
        min-height: auto;
    }

    .feature-image img {
        height: auto;
        max-height: none;
    }
}

/* Steps */
.steps {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
    margin-bottom: 32px;
}

.step {
    text-align: center;
    padding: 28px 20px;
}

.step-number {
    width: 48px;
    height: 48px;
    background: var(--color-gold);
    color: var(--color-deep-blue);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
    font-weight: 700;
    margin: 0 auto 16px;
}

.step h4 {
    font-size: 16px;
    color: var(--color-deep-blue);
    margin-bottom: 8px;
}

.step p {
    font-size: 14px;
    color: var(--color-medium-gray);
}

.steps-image {
    text-align: center;
}

.steps-image img {
    max-width: 100%;
    height: auto;
    object-fit: cover;
    border-radius: 10px;
}

/* FAQ */
.faq-list {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    border-bottom: 1px solid #e0e0e0;
}

.faq-question {
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 0;
    background: transparent;
    border: none;
    font-size: 16px;
    font-weight: 600;
    color: var(--color-deep-blue);
    cursor: pointer;
    text-align: left;
}

.faq-question:hover {
    color: var(--color-burgundy);
}

.faq-icon {
    font-size: 20px;
    transition: transform 0.3s ease;
}

.faq-item.active .faq-icon {
    transform: rotate(45deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
}

.faq-answer-inner {
    padding: 0 0 20px;
    color: var(--color-medium-gray);
    font-size: 15px;
    line-height: 1.8;
}

/* CTA Section */
.cta-section {
    background: linear-gradient(135deg, var(--color-deep-blue) 0%, #1a2d5a 100%);
    color: var(--color-white);
    text-align: center;
    padding: 70px 0;
}

.cta-section h2 {
    font-size: 30px;
    margin-bottom: 16px;
}

.cta-section p {
    font-size: 16px;
    opacity: 0.9;
    margin-bottom: 32px;
}

.cta-buttons {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
}

.cta-buttons .btn-secondary {
    border-color: var(--color-white);
    color: var(--color-white);
}

.cta-buttons .btn-secondary:hover {
    background: var(--color-white);
    color: var(--color-deep-blue);
}

/* Footer */
.footer {
    background: var(--color-deep-blue);
    color: var(--color-white);
    padding: 40px 0;
}

.footer-top {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 32px;
    flex-wrap: wrap;
    gap: 20px;
}

.footer-logo {
    font-size: 18px;
    font-weight: 600;
}

.footer-links {
    display: flex;
    gap: 32px;
    flex-wrap: wrap;
}

.footer-link {
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
    font-size: 14px;
}

.footer-link:hover {
    color: var(--color-white);
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 24px;
}

.footer-disclaimer {
    font-size: 13px;
    opacity: 0.75;
    line-height: 1.7;
}

/* Download Page */
.download-section {
    padding: 48px 0;
}

.download-section h3 {
    font-size: 22px;
    color: var(--color-deep-blue);
    margin-bottom: 20px;
}

.download-section p {
    color: var(--color-medium-gray);
    font-size: 15px;
    line-height: 1.8;
    margin-bottom: 16px;
}

.download-section ul {
    margin-left: 24px;
    margin-bottom: 16px;
}

.download-section li {
    color: var(--color-medium-gray);
    font-size: 15px;
    line-height: 1.8;
    margin-bottom: 8px;
}

.checklist {
    background: var(--color-light-gray);
    border-radius: 10px;
    padding: 28px;
}

.checklist h4 {
    font-size: 18px;
    color: var(--color-deep-blue);
    margin-bottom: 20px;
}

.checklist-items {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
}

.checklist-item {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 15px;
    color: var(--color-dark-gray);
}

.checklist-item::before {
    content: "✓";
    color: var(--color-gold);
    font-weight: 700;
}

/* List Page */
.category-filter {
    display: flex;
    gap: 12px;
    margin-bottom: 40px;
    flex-wrap: wrap;
    justify-content: center;
}

.category-btn {
    padding: 10px 24px;
    background: var(--color-white);
    border: 1px solid #e0e0e0;
    border-radius: 6px;
    font-size: 14px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.category-btn:hover,
.category-btn.active {
    background: var(--color-burgundy);
    color: var(--color-white);
    border-color: var(--color-burgundy);
}

.article-list {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 24px;
}

.article-card {
    background: var(--color-white);
    border-radius: 10px;
    overflow: hidden;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.06);
    transition: transform 0.3s ease;
}

.article-card:hover {
    transform: translateY(-4px);
}

.article-card-image img {
    width: 100%;
    height: 180px;
    object-fit: cover;
}

.article-card-content {
    padding: 24px;
}

.article-card-meta {
    font-size: 13px;
    color: var(--color-gold);
    margin-bottom: 8px;
}

.article-card h4 {
    font-size: 18px;
    color: var(--color-deep-blue);
    margin-bottom: 12px;
}

.article-card p {
    font-size: 14px;
    color: var(--color-medium-gray);
    line-height: 1.7;
}

.list-page-inner {
    display: grid;
    grid-template-columns: 1fr 300px;
    gap: 40px;
}

.sidebar-widget {
    background: var(--color-white);
    border-radius: 10px;
    padding: 24px;
    margin-bottom: 24px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.06);
}

.sidebar-widget h4 {
    font-size: 18px;
    color: var(--color-deep-blue);
    margin-bottom: 20px;
}

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

.sidebar-list li {
    padding: 10px 0;
    border-bottom: 1px solid #f0f0f0;
}

.sidebar-list li:last-child {
    border-bottom: none;
}

.sidebar-list a {
    color: var(--color-dark-gray);
    text-decoration: none;
    font-size: 14px;
}

.sidebar-list a:hover {
    color: var(--color-burgundy);
}

/* Show Page */
.article-page {
    max-width: 800px;
    margin: 0 auto;
}

.article-header {
    margin-bottom: 40px;
}

.article-meta {
    color: var(--color-gold);
    font-size: 14px;
    margin-bottom: 16px;
}

.article-cover {
    width: 100%;
    height: 360px;
    object-fit: cover;
    border-radius: 10px;
    margin-bottom: 40px;
}

.article-content {
    font-size: 16px;
    line-height: 1.9;
}

.article-content h3 {
    font-size: 22px;
    color: var(--color-deep-blue);
    margin: 36px 0 16px;
}

.article-content h4 {
    font-size: 18px;
    color: var(--color-dark-gray);
    margin: 28px 0 12px;
}

.article-content p {
    color: var(--color-dark-gray);
    margin-bottom: 16px;
}

.article-content ul,
.article-content ol {
    margin: 16px 0 16px 24px;
}

.article-content li {
    margin-bottom: 8px;
    color: var(--color-dark-gray);
}

.article-content img {
    width: 100%;
    height: auto;
    object-fit: cover;
    border-radius: 10px;
    margin: 24px 0;
}

/* Back to Top */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: var(--color-burgundy);
    color: var(--color-white);
    border: none;
    border-radius: 50%;
    font-size: 20px;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    z-index: 999;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    background: #721710;
}

/* Responsive */
@media (max-width: 992px) {
    .hero-inner {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .hero-image {
        order: -1;
    }
    
    .hero-buttons {
        justify-content: center;
    }
    
    .cards-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .feature-block {
        grid-template-columns: 1fr;
    }
    
    .feature-block-reverse {
        direction: ltr;
    }
    
    .steps {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .list-page-inner {
        grid-template-columns: 1fr;
    }
    
    .sidebar {
        display: none;
    }
}

@media (max-width: 768px) {
    .nav {
        display: none;
        position: absolute;
        top: 70px;
        left: 0;
        right: 0;
        background: var(--color-white);
        flex-direction: column;
        padding: 20px;
        box-shadow: 0 4px 8px rgba(0, 0, 0, 0.08);
    }
    
    .nav.active {
        display: flex;
    }
    
    .nav-list {
        flex-direction: column;
        gap: 16px;
    }
    
    .mobile-menu-btn {
        display: flex;
    }
    
    .hero {
        padding: 50px 0;
    }
    
    .hero-content h1 {
        font-size: 26px;
    }
    
    .hero-features {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .section {
        padding: 48px 0;
    }
    
    .section-header h2 {
        font-size: 24px;
    }
    
    .cards-grid {
        grid-template-columns: 1fr;
    }
    
    .steps {
        grid-template-columns: 1fr;
    }
    
    .article-list {
        grid-template-columns: 1fr;
    }
    
    .checklist-items {
        grid-template-columns: 1fr;
    }
    
    .footer-top {
        flex-direction: column;
        text-align: center;
    }
    
    .footer-links {
        justify-content: center;
    }
    
    .article-cover {
        height: 240px;
    }
}