/* CSS Variables */
:root {
    --primary-color: #1a73e8;
    --primary-dark: #1557b0;
    --secondary-color: #34a853;
    --accent-color: #ea4335;
    --warning-color: #fbbc04;
    --dark-color: #202124;
    --gray-900: #202124;
    --gray-800: #3c4043;
    --gray-700: #5f6368;
    --gray-600: #80868b;
    --gray-500: #9aa0a6;
    --gray-400: #bdc1c6;
    --gray-300: #dadce0;
    --gray-200: #e8eaed;
    --gray-100: #f8f9fa;
    --white: #ffffff;
    --shadow-sm: 0 1px 2px 0 rgba(60,64,67,0.3), 0 1px 3px 1px rgba(60,64,67,0.15);
    --shadow-md: 0 1px 3px 0 rgba(60,64,67,0.3), 0 4px 8px 3px rgba(60,64,67,0.15);
    --shadow-lg: 0 1px 3px 0 rgba(60,64,67,0.3), 0 8px 16px 4px rgba(60,64,67,0.15);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --transition: all 0.3s ease;
}

/* Reset & Base */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: var(--gray-800);
    background-color: var(--white);
}

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

a:hover {
    color: var(--primary-dark);
}

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

/* Container */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ===================================
   导航栏 (与CBAM一致的结构)
   =================================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: var(--white);
    border-bottom: 1px solid var(--gray-300);
    z-index: 1000;
    transition: var(--transition);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 60px;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: 600;
    font-size: 1.2rem;
    color: var(--primary-color);
    text-decoration: none;
}

.logo-badge {
    width: 32px;
    height: 32px;
    border-radius: 6px;
    background: var(--primary-color);
    display: flex;
    align-items: center;
    justify-content: center;
}

.logo-badge-text {
    color: white;
    font-weight: bold;
    font-size: 12px;
}

.logo-text {
    color: var(--gray-900);
    font-weight: 600;
}

.nav-menu {
    display: flex;
    gap: 8px;
    list-style: none;
    padding: 0;
    margin: 0;
}

.nav-link {
    padding: 8px 16px;
    border-radius: var(--radius-md);
    color: var(--gray-800);
    font-weight: 500;
    transition: var(--transition);
}

.nav-link:hover,
.nav-link.active {
    background: var(--primary-color);
    color: var(--white);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    padding: 8px;
    background: none;
    border: none;
    cursor: pointer;
}

.nav-toggle span {
    width: 24px;
    height: 2px;
    background: var(--gray-800);
    transition: var(--transition);
}

/* ===================================
   面包屑导航
   =================================== */
.breadcrumb {
    padding: 8px 0;
    background: var(--gray-100);
    border-bottom: 1px solid var(--gray-200);
    margin-top: 60px;
    position: sticky;
    top: 60px;
    z-index: 999;
}

.breadcrumb-list {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 8px;
    list-style: none;
    padding: 0;
    margin: 0;
    font-size: 0.85rem;
}

.breadcrumb-item {
    display: flex;
    align-items: center;
    gap: 8px;
}

.breadcrumb-item a {
    color: var(--gray-600);
    text-decoration: none;
    transition: var(--transition);
}

.breadcrumb-item a:hover {
    color: var(--primary-color);
}

.breadcrumb-item.active {
    color: var(--gray-800);
    font-weight: 500;
}

.breadcrumb-separator {
    color: var(--gray-400);
}

/* Hero Section */
.hero {
    padding: 120px 0 80px;
    background: linear-gradient(135deg, #f0f7ff 0%, #e8f4e8 100%);
}

.hero-content {
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
}

.hero-title {
    font-size: 48px;
    font-weight: 700;
    line-height: 1.2;
    color: var(--gray-900);
    margin-bottom: 24px;
}

.hero-title .highlight {
    color: var(--primary-color);
}

.hero-subtitle {
    font-size: 20px;
    color: var(--gray-700);
    margin-bottom: 40px;
}

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

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 24px;
    font-size: 16px;
    font-weight: 500;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
    border: 2px solid transparent;
}

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

.btn-primary:hover {
    background: var(--primary-dark);
    color: var(--white);
    box-shadow: var(--shadow-md);
}

.btn-outline {
    background: transparent;
    color: var(--primary-color);
    border-color: var(--primary-color);
}

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

.btn-large {
    padding: 16px 32px;
    font-size: 18px;
}

/* Sections */
.section {
    padding: 80px 0;
}

.section-title {
    font-size: 32px;
    font-weight: 600;
    text-align: center;
    color: var(--gray-900);
    margin-bottom: 48px;
}

/* Cards Grid */
.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 24px;
}

.card {
    background: var(--white);
    border-radius: var(--radius-lg);
    padding: 32px;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-4px);
}

.card-icon {
    font-size: 48px;
    margin-bottom: 16px;
}

.card-title {
    font-size: 20px;
    font-weight: 600;
    color: var(--gray-900);
    margin-bottom: 12px;
}

.card-text {
    color: var(--gray-700);
    font-size: 15px;
}

/* Timeline */
.timeline-section {
    background: var(--gray-100);
}

.timeline {
    position: relative;
    max-width: 800px;
    margin: 0 auto;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 120px;
    top: 0;
    bottom: 0;
    width: 2px;
    background: var(--primary-color);
}

.timeline-item {
    display: flex;
    gap: 24px;
    margin-bottom: 32px;
    position: relative;
}

.timeline-item:last-child {
    margin-bottom: 0;
}

.timeline-date {
    width: 100px;
    text-align: right;
    font-weight: 600;
    color: var(--primary-color);
    font-size: 14px;
    flex-shrink: 0;
    padding-top: 4px;
}

.timeline-content {
    flex: 1;
    background: var(--white);
    padding: 20px 24px;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    margin-left: 24px;
    position: relative;
}

.timeline-content::before {
    content: '';
    position: absolute;
    left: -32px;
    top: 12px;
    width: 12px;
    height: 12px;
    background: var(--primary-color);
    border-radius: 50%;
    border: 3px solid var(--white);
    box-shadow: var(--shadow-sm);
}

.timeline-content h3 {
    font-size: 18px;
    font-weight: 600;
    color: var(--gray-900);
    margin-bottom: 8px;
}

.timeline-content p {
    color: var(--gray-700);
    font-size: 14px;
}

/* Battery Types */
.types-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
}

.type-card {
    background: var(--white);
    border: 1px solid var(--gray-300);
    border-radius: var(--radius-md);
    padding: 24px;
    transition: var(--transition);
}

.type-card:hover {
    border-color: var(--primary-color);
    box-shadow: var(--shadow-sm);
}

.type-card h3 {
    font-size: 18px;
    font-weight: 600;
    color: var(--gray-900);
    margin-bottom: 16px;
    padding-bottom: 12px;
    border-bottom: 2px solid var(--gray-200);
}

.type-card ul {
    list-style: none;
}

.type-card li {
    position: relative;
    padding-left: 20px;
    margin-bottom: 8px;
    color: var(--gray-700);
    font-size: 14px;
}

.type-card li::before {
    content: '•';
    position: absolute;
    left: 0;
    color: var(--primary-color);
    font-weight: bold;
}

.highlight-card {
    border-color: var(--primary-color);
    background: linear-gradient(135deg, #f0f7ff 0%, var(--white) 100%);
}

/* CTA Section - 与CBAM一致的深色卡片风格 */
.cta-section {
    background: var(--gray-900);
    color: var(--white);
    padding: 48px 40px;
    border-radius: var(--radius-lg);
    text-align: center;
}

.cta-section .cta-content {
    max-width: 600px;
    margin: 0 auto;
}

.cta-section h2 {
    font-size: 28px;
    font-weight: 600;
    margin-bottom: 16px;
    color: var(--white);
}

.cta-section p {
    color: var(--gray-400);
    margin-bottom: 32px;
}

/* ===================================
   页脚 (与CBAM一致的结构)
   =================================== */
.footer {
    background: #f5f7f9;
    color: #333333;
    padding: 50px 0 20px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 40px;
    margin-bottom: 32px;
}

.footer-brand {
    max-width: 300px;
}

.footer-brand-header {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 12px;
    text-decoration: none;
}

.footer-brand .logo-badge {
    width: 32px;
    height: 32px;
    border-radius: 6px;
    background: var(--primary-color);
    display: flex;
    align-items: center;
    justify-content: center;
}

.footer-brand .logo-badge-text {
    color: white;
    font-weight: bold;
    font-size: 12px;
}

.footer-brand .logo-text {
    font-size: 1.15rem;
    font-weight: 600;
    color: #222222;
}

.footer-brand p {
    margin-top: 12px;
    color: #666666;
    font-size: 0.85rem;
    line-height: 1.6;
}

.footer-brand .brand-note {
    margin-top: 16px;
    color: #718096;
    font-size: 12px;
}

.footer-brand .brand-note a {
    color: var(--primary-color);
}

.footer-brand .brand-note a:hover {
    text-decoration: underline;
}

.footer-links h4,
.footer-external h4 {
    font-size: 0.95rem;
    margin-bottom: 14px;
    font-weight: 600;
    color: #222222;
}

.footer-links ul,
.footer-external ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.footer-links ul li,
.footer-external ul li {
    margin-bottom: 6px;
}

.footer-links a,
.footer-external a {
    color: #333333;
    font-size: 0.85rem;
    transition: var(--transition);
}

.footer-links a:hover,
.footer-external a:hover {
    color: var(--primary-color);
}

.footer-bottom {
    padding-top: 20px;
    border-top: 1px solid #e0e0e0;
    text-align: center;
    color: #666666;
    font-size: 0.8rem;
}

/* FAQ Page Styles */
.page-header {
    padding: 120px 0 48px;
    background: linear-gradient(135deg, #f0f7ff 0%, #e8f4e8 100%);
    text-align: center;
}

.page-header h1 {
    font-size: 36px;
    font-weight: 700;
    color: var(--gray-900);
    margin-bottom: 16px;
}

.page-header p {
    font-size: 18px;
    color: var(--gray-700);
}

.faq-section {
    padding: 48px 0;
}

.faq-category {
    margin-bottom: 48px;
}

.faq-category-title {
    font-size: 24px;
    font-weight: 600;
    color: var(--gray-900);
    margin-bottom: 24px;
    padding-bottom: 12px;
    border-bottom: 2px solid var(--primary-color);
}

.faq-item {
    background: var(--white);
    border: 1px solid var(--gray-300);
    border-radius: var(--radius-md);
    margin-bottom: 16px;
    overflow: hidden;
}

.faq-question {
    width: 100%;
    text-align: left;
    padding: 20px 24px;
    background: none;
    border: none;
    font-size: 16px;
    font-weight: 500;
    color: var(--gray-900);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: var(--transition);
}

.faq-question:hover {
    background: var(--gray-100);
}

.faq-question::after {
    content: '+';
    font-size: 24px;
    font-weight: 300;
    color: var(--primary-color);
    transition: var(--transition);
}

.faq-item.active .faq-question::after {
    content: '−';
}

.faq-answer {
    padding: 0 24px;
    max-height: 0;
    overflow: hidden;
    transition: all 0.3s ease;
}

.faq-item.active .faq-answer {
    padding: 0 24px 20px;
    max-height: 1000px;
}

.faq-answer p {
    color: var(--gray-700);
    margin-bottom: 12px;
    font-size: 15px;
}

.faq-answer .official,
.faq-answer .third-party {
    margin-bottom: 16px;
    padding: 16px;
    border-radius: var(--radius-sm);
}

.faq-answer .official {
    background: #e8f4e8;
    border-left: 4px solid var(--secondary-color);
}

.faq-answer .third-party {
    background: #fff8e1;
    border-left: 4px solid var(--warning-color);
}

.faq-answer .label {
    font-weight: 600;
    margin-bottom: 8px;
    font-size: 14px;
}

.faq-answer .source {
    font-size: 13px;
    color: var(--gray-600);
    font-style: italic;
}

/* Guide Page Styles */
.guide-section {
    padding: 48px 0;
}

.guide-phase {
    margin-bottom: 48px;
    background: var(--white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    overflow: hidden;
}

.phase-header {
    background: var(--primary-color);
    color: var(--white);
    padding: 24px 32px;
}

.phase-header h2 {
    font-size: 22px;
    font-weight: 600;
    margin-bottom: 8px;
}

.phase-header .phase-goal {
    opacity: 0.9;
    font-size: 14px;
}

.phase-content {
    padding: 32px;
}

.step {
    margin-bottom: 32px;
    padding-bottom: 32px;
    border-bottom: 1px solid var(--gray-200);
}

.step:last-child {
    margin-bottom: 0;
    padding-bottom: 0;
    border-bottom: none;
}

.step h3 {
    font-size: 18px;
    font-weight: 600;
    color: var(--gray-900);
    margin-bottom: 16px;
}

.step h3::before {
    content: attr(data-step);
    display: inline-block;
    background: var(--primary-color);
    color: var(--white);
    padding: 4px 12px;
    border-radius: var(--radius-sm);
    font-size: 12px;
    margin-right: 12px;
}

.step-list {
    list-style: none;
    margin-bottom: 16px;
}

.step-list li {
    position: relative;
    padding-left: 24px;
    margin-bottom: 12px;
    color: var(--gray-700);
}

.step-list li::before {
    content: '▸';
    position: absolute;
    left: 0;
    color: var(--primary-color);
}

.step-meta {
    display: flex;
    gap: 24px;
    flex-wrap: wrap;
    margin-top: 16px;
}

.step-meta-item {
    background: var(--gray-100);
    padding: 12px 16px;
    border-radius: var(--radius-sm);
    font-size: 14px;
}

.step-meta-item strong {
    display: block;
    color: var(--gray-900);
    margin-bottom: 4px;
}

.step-meta-item span {
    color: var(--gray-700);
}

.risk-tag {
    display: inline-block;
    background: #ffebee;
    color: #c62828;
    padding: 4px 8px;
    border-radius: 4px;
    font-size: 12px;
    margin-top: 8px;
}

/* Report Page Styles */
.report-section {
    padding: 48px 0;
}

.report-card {
    background: var(--white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    margin-bottom: 32px;
    overflow: hidden;
}

.report-header {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: var(--white);
    padding: 24px 32px;
    display: flex;
    align-items: center;
    gap: 16px;
}

.report-number {
    background: rgba(255,255,255,0.2);
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 18px;
}

.report-header h2 {
    font-size: 20px;
    font-weight: 600;
}

.report-content {
    padding: 32px;
}

.report-item {
    margin-bottom: 20px;
}

.report-item:last-child {
    margin-bottom: 0;
}

.report-item h3 {
    font-size: 16px;
    font-weight: 600;
    color: var(--gray-900);
    margin-bottom: 8px;
}

.report-item p,
.report-item ul {
    color: var(--gray-700);
    font-size: 15px;
}

.report-item ul {
    list-style: none;
    margin-top: 8px;
}

.report-item li {
    position: relative;
    padding-left: 20px;
    margin-bottom: 6px;
}

.report-item li::before {
    content: '•';
    position: absolute;
    left: 0;
    color: var(--primary-color);
}

.urgent-badge {
    display: inline-block;
    background: #ffebee;
    color: #c62828;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
    margin-left: 12px;
}

.role-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 24px;
}

.role-table th,
.role-table td {
    padding: 16px;
    text-align: left;
    border-bottom: 1px solid var(--gray-200);
}

.role-table th {
    background: var(--gray-100);
    font-weight: 600;
    color: var(--gray-900);
}

.role-table td {
    color: var(--gray-700);
    font-size: 14px;
}

/* Risk Page Styles */
.risk-section {
    padding: 48px 0;
}

.risk-card {
    background: var(--white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    margin-bottom: 24px;
    overflow: hidden;
    border-left: 4px solid var(--gray-400);
}

.risk-card.high-risk {
    border-left-color: var(--accent-color);
}

.risk-card.medium-risk {
    border-left-color: var(--warning-color);
}

.risk-header {
    padding: 24px;
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    cursor: pointer;
}

.risk-title {
    flex: 1;
}

.risk-number {
    font-size: 12px;
    color: var(--gray-600);
    margin-bottom: 8px;
}

.risk-header h3 {
    font-size: 18px;
    font-weight: 600;
    color: var(--gray-900);
}

.risk-level {
    display: flex;
    align-items: center;
    gap: 8px;
}

.risk-score {
    background: var(--gray-100);
    padding: 8px 16px;
    border-radius: var(--radius-sm);
    font-weight: 600;
}

.risk-card.high-risk .risk-score {
    background: #ffebee;
    color: #c62828;
}

.risk-card.medium-risk .risk-score {
    background: #fff8e1;
    color: #f57c00;
}

.risk-content {
    padding: 0 24px 24px;
    display: none;
}

.risk-card.active .risk-content {
    display: block;
}

.risk-detail {
    margin-bottom: 20px;
}

.risk-detail h4 {
    font-size: 14px;
    font-weight: 600;
    color: var(--gray-900);
    margin-bottom: 8px;
}

.risk-detail p {
    color: var(--gray-700);
    font-size: 14px;
}

.possibility-bar {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-top: 8px;
}

.bar-label {
    font-size: 13px;
    color: var(--gray-700);
    width: 60px;
}

.bar-track {
    flex: 1;
    height: 8px;
    background: var(--gray-200);
    border-radius: 4px;
    overflow: hidden;
}

.bar-fill {
    height: 100%;
    border-radius: 4px;
}

.bar-fill.high {
    background: var(--accent-color);
}

.bar-fill.medium {
    background: var(--warning-color);
}

.bar-fill.low {
    background: var(--secondary-color);
}

/* ===================================
   响应式设计
   =================================== */
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 64px;
        left: 0;
        right: 0;
        background: var(--white);
        flex-direction: column;
        padding: 24px;
        gap: 8px;
        box-shadow: var(--shadow-md);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: var(--transition);
    }

    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }

    .nav-toggle {
        display: flex;
    }

    .hero {
        padding: 100px 0 60px;
    }

    .hero-title {
        font-size: 32px;
    }

    .hero-subtitle {
        font-size: 16px;
    }

    .section {
        padding: 48px 0;
    }

    .section-title {
        font-size: 24px;
    }

    .timeline::before {
        left: 20px;
    }

    .timeline-item {
        flex-direction: column;
    }

    .timeline-date {
        width: 100%;
        text-align: left;
        margin-bottom: 8px;
        padding-left: 44px;
    }

    .timeline-content {
        margin-left: 44px;
    }

    .timeline-content::before {
        left: -36px;
    }

    .footer-content {
        flex-direction: column;
    }

    .role-table {
        font-size: 13px;
    }

    .role-table th,
    .role-table td {
        padding: 12px 8px;
    }
}