/* 
 * 黑大智能官网 - 全局样式文件
 * 基于 Design System: Trust & Authority
 */

@import url('https://fonts.googleapis.com/css2?family=Lexend:wght@300;400;500;600;700&family=Source+Sans+3:wght@300;400;500;600;700&display=swap');

:root {
    /* Color Palette - Industrial slate + Emerald */
    --color-primary: #334155;
    --color-on-primary: #FFFFFF;
    --color-secondary: #475569;
    --color-accent: #059669;
    --color-background: #F8FAFC;
    --color-foreground: #0F172A;
    --color-muted: #F1F5F9;
    --color-border: #E2E8F0;
    --color-destructive: #DC2626;
    --color-ring: #334155;

    /* Spacing Scale (Density 5/10) */
    --space-xs: 0.5rem;   /* 8px */
    --space-sm: 1rem;     /* 16px */
    --space-md: 1.5rem;   /* 24px */
    --space-lg: 2rem;     /* 32px */
    --space-xl: 3rem;     /* 48px */
    --space-xxl: 4rem;    /* 64px */
    --space-3xl: 6rem;    /* 96px */

    /* Typography */
    --font-heading: 'Lexend', sans-serif;
    --font-body: 'Source Sans 3', sans-serif;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-body);
    color: var(--color-foreground);
    background-color: var(--color-background);
    line-height: 1.6;
    overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    color: var(--color-primary);
    font-weight: 700;
}

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

ul {
    list-style: none;
}

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

.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
}

.section-padding {
    padding: var(--space-3xl) 0;
}

.bg-light {
    background-color: var(--color-light);
}

.bg-dark {
    background-color: var(--color-primary);
    color: #FFFFFF;
}

.bg-dark .section-desc {
    color: rgba(255, 255, 255, 0.7);
}

.bg-dark .contact-list li span {
    color: rgba(255, 255, 255, 0.9);
}

.text-white {
    color: #FFFFFF !important;
}

/* Header Styles */
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    background-color: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--color-border);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.header .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 80px;
}

.logo-text {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--color-primary);
    font-family: var(--font-heading);
    letter-spacing: -0.02em;
}

.nav-desktop .nav-list {
    display: flex;
    gap: 40px;
}

.nav-link {
    text-decoration: none;
    color: var(--color-secondary);
    font-weight: 600;
    font-family: var(--font-heading);
    font-size: 0.9rem;
    transition: color 0.3s ease;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.nav-link:hover, .nav-link.active {
    color: var(--color-accent);
}

.header-actions .btn-primary {
    background-color: var(--color-primary);
    color: #FFFFFF;
    border-radius: 50px;
    padding: 0.6rem 1.8rem;
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.header-actions .btn-primary:hover {
    background-color: var(--color-accent);
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(5, 150, 105, 0.2);
}

/* Button Styles */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    font-weight: 600;
    font-family: var(--font-heading);
    cursor: pointer;
    transition: all 0.3s ease;
    border: none;
    text-decoration: none;
    gap: 8px;
}

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

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

.btn-accent {
    background-color: var(--color-accent);
    color: #FFFFFF;
}

.btn-accent:hover {
    background-color: #047857; /* Darker emerald */
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(5, 150, 105, 0.3);
}

.btn-outline-white {
    background: transparent;
    border: 1px solid rgba(255, 255, 255, 0.5);
    color: #FFFFFF;
}

.btn-outline-white:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: #FFFFFF;
}

.btn-lg {
    padding: 1rem 2rem;
    font-size: 1.125rem;
}

.w-full {
    width: 100%;
}

/* Mobile Nav Toggle */
.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    color: var(--color-primary);
    cursor: pointer;
}

/* Hero Styles */
.hero {
    position: relative;
    height: 100vh;
    min-height: 700px;
    display: flex;
    align-items: center;
    color: #FFFFFF;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
}

.hero-bg img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.hero-bg::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(to right, rgba(15, 23, 42, 0.95) 0%, rgba(15, 23, 42, 0.6) 60%, rgba(15, 23, 42, 0.3) 100%);
}

.hero-content {
    max-width: 900px;
    position: relative;
    z-index: 1;
    padding-top: 80px; /* Account for fixed header */
}

.hero-content h1 {
    font-size: clamp(3rem, 8vw, 5rem);
    line-height: 1.1;
    margin-bottom: var(--space-md);
    letter-spacing: -0.04em;
    font-weight: 800;
    color: #FFFFFF !important; /* Force white text */
}

.hero-subtitle {
    font-size: clamp(1.1rem, 2vw, 1.4rem);
    max-width: 700px;
    margin-bottom: var(--space-xl);
    color: rgba(255, 255, 255, 0.85);
    line-height: 1.6;
}

.hero-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    margin-bottom: 40px;
}

.hero-tags span {
    padding: 8px 20px;
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.3);
    border-radius: 50px;
    font-size: 0.9rem;
    font-weight: 500;
    backdrop-filter: blur(8px);
    color: #FFFFFF;
}

.hero-btns {
    display: flex;
    gap: 20px;
}

/* Section Header */
.section-header {
    margin-bottom: var(--space-xxl);
    max-width: 800px;
}

.section-tag {
    display: inline-block;
    color: var(--color-accent);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    font-size: 0.875rem;
    margin-bottom: var(--space-sm);
}

.section-title {
    font-size: clamp(2.5rem, 5vw, 3.5rem);
    line-height: 1.1;
    margin-bottom: var(--space-md);
    letter-spacing: -0.02em;
}

.section-desc {
    font-size: 1.125rem;
    color: var(--color-secondary);
    line-height: 1.6;
}

/* About Section Refinement */
.about-grid-v2 {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-xxl);
    align-items: start;
}

.about-info-panel {
    position: sticky;
    top: 120px;
}

.about-intro {
    font-size: 1.125rem;
    color: var(--color-secondary);
    margin-bottom: var(--space-xl);
    line-height: 1.7;
}

.about-intro p {
    margin-bottom: var(--space-md);
}

.about-bento {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-md);
}

.bento-item {
    background: #FFFFFF;
    padding: var(--space-lg);
    border-radius: 20px;
    border: 1px solid var(--color-border);
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.bento-item:hover {
    transform: translateY(-8px);
    box-shadow: 0 20px 40px -10px rgba(15, 23, 42, 0.08);
    border-color: var(--color-accent);
}

.bento-item.full-width {
    grid-column: span 2;
}

.bento-item h4 {
    font-size: 1.25rem;
    margin-bottom: var(--space-sm);
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    color: var(--color-primary);
}

.bento-item i {
    color: var(--color-accent);
    width: 24px;
    height: 24px;
}

.bento-item p {
    color: var(--color-secondary);
    font-size: 0.95rem;
    line-height: 1.6;
}

.about-stats-v2 {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-xl);
    margin-top: var(--space-xl);
    padding-top: var(--space-xl);
    border-top: 1px solid var(--color-border);
}

.stat-item-v2 .number {
    display: block;
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 800;
    color: var(--color-primary);
    line-height: 1;
    margin-bottom: var(--space-xs);
    font-family: var(--font-heading);
    letter-spacing: -0.02em;
}

.stat-item-v2 .label {
    font-size: 0.875rem;
    color: var(--color-secondary);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* About Section */
.about-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}

.about-image img {
    border-radius: 12px;
    box-shadow: 0 20px 40px rgba(0,0,0,0.1);
}

.about-tabs {
    display: flex;
    gap: 20px;
    margin-bottom: 30px;
    border-bottom: 1px solid var(--color-border);
}

.tab-btn {
    background: none;
    border: none;
    padding: 10px 0;
    font-weight: 600;
    color: var(--color-secondary);
    cursor: pointer;
    position: relative;
}

.tab-btn.active {
    color: var(--color-accent);
}

.tab-btn.active::after {
    content: '';
    position: absolute;
    bottom: -1px;
    left: 0;
    width: 100%;
    height: 2px;
    background-color: var(--color-accent);
}

.tab-pane {
    display: none;
}

.tab-pane.active {
    display: block;
}

.tab-pane h3 {
    margin-bottom: 15px;
    font-size: 1.5rem;
}

.check-list {
    margin-top: 20px;
}

.check-list li {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 10px;
}

.check-list li::before {
    content: '✓';
    color: var(--color-accent);
    font-weight: 700;
}

.strength-stats {
    display: flex;
    gap: 40px;
    margin-top: 30px;
}

.stat-item {
    display: flex;
    flex-direction: column;
}

.stat-num {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--color-accent);
    font-family: var(--font-heading);
}

.stat-label {
    color: var(--color-secondary);
    font-weight: 500;
}

/* Product Section */
.product-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.product-card {
    background: #FFFFFF;
    border-radius: 12px;
    overflow: hidden;
    transition: var(--transition-base);
    border: 1px solid var(--color-border);
}

.product-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 40px rgba(0,0,0,0.08);
}

.product-img img {
    width: 100%;
    height: 240px;
    object-fit: cover;
}

.product-info {
    padding: 30px;
}

.product-info h3 {
    margin-bottom: 10px;
    font-size: 1.25rem;
}

.product-info p {
    color: var(--color-secondary);
    margin-bottom: 20px;
}

.btn-text {
    display: inline-flex;
    align-items: center;
    gap: 5px;
    color: var(--color-accent);
    font-weight: 700;
}

/* Solution Section */
.solution-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.solution-card {
    background: #FFFFFF;
    border-radius: 12px;
    overflow: hidden;
    transition: var(--transition-base);
    border: 1px solid var(--color-border);
}

.solution-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 40px rgba(0,0,0,0.08);
}

.solution-img img {
    width: 100%;
    height: 240px;
    object-fit: cover;
}

.solution-info {
    padding: 30px;
}

.solution-icon {
    width: 40px;
    height: 40px;
    color: var(--color-accent);
    margin-bottom: 15px;
}

.solution-info h3 {
    margin-bottom: 10px;
    font-size: 1.5rem;
}

.solution-info p {
    color: var(--color-secondary);
}

/* Cases Section */
.case-carousel {
    display: flex;
    justify-content: space-around;
    align-items: center;
    flex-wrap: wrap;
    gap: 40px;
}

.case-logo img {
    height: 60px;
    filter: grayscale(1) opacity(0.5);
    transition: var(--transition-base);
}

.case-logo:hover img {
    filter: grayscale(0) opacity(1);
}

/* News Section */
.news-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.news-card {
    background: #FFFFFF;
    border-radius: 12px;
    overflow: hidden;
    border: 1px solid var(--color-border);
    transition: var(--transition-base);
}

.news-card:hover {
    box-shadow: 0 10px 30px rgba(0,0,0,0.05);
}

.news-img img {
    width: 100%;
    height: 200px;
    object-fit: cover;
}

.news-info {
    padding: 25px;
}

.news-date {
    font-size: 0.875rem;
    color: var(--color-accent);
    font-weight: 600;
    margin-bottom: 10px;
    display: block;
}

.news-info h3 {
    font-size: 1.125rem;
    margin-bottom: 15px;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

/* Contact Section */
.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
}

.contact-list {
    margin-top: 40px;
}

.contact-list li {
    display: flex;
    align-items: center;
    gap: 20px;
    margin-bottom: 25px;
}

.contact-list i {
    color: var(--color-accent);
}

.contact-form {
    background: rgba(255,255,255,0.05);
    padding: 40px;
    border-radius: 12px;
    border: 1px solid rgba(255,255,255,0.1);
}

.form-group {
    margin-bottom: 20px;
}

.form-group input, .form-group textarea {
    width: 100%;
    padding: 12px 16px;
    background: rgba(255,255,255,0.1);
    border: 1px solid rgba(255,255,255,0.2);
    border-radius: 6px;
    color: #FFFFFF;
    font-family: inherit;
}

.form-group input::placeholder, .form-group textarea::placeholder {
    color: rgba(255,255,255,0.5);
}

.form-group input:focus, .form-group textarea:focus {
    outline: none;
    border-color: var(--color-accent);
    background: rgba(255,255,255,0.15);
}

/* Footer Section */
.footer {
    background-color: #1E293B; /* Slightly darker than primary for distinction */
    color: rgba(255, 255, 255, 0.6);
    padding: var(--space-xxl) 0 var(--space-lg);
    font-size: 0.9rem;
}

.footer h3, .footer h4 {
    color: #FFFFFF;
    margin-bottom: var(--space-md);
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    margin-top: var(--space-xl);
    padding-top: var(--space-lg);
}

.footer-bottom p {
    color: rgba(255, 255, 255, 0.5);
}

.footer-links {
    display: flex;
    gap: 30px;
}

.footer-links a {
    color: rgba(255, 255, 255, 0.5);
    transition: color 0.3s ease;
}

.footer-links a:hover {
    color: #FFFFFF;
}

/* Mobile Navigation Overlay */
.mobile-nav {
    position: fixed;
    top: 0;
    right: -100%;
    width: 100%;
    height: 100%;
    background: #FFFFFF;
    z-index: 2000;
    transition: 0.4s cubic-bezier(0.77,0.2,0.05,1.0);
    padding: 40px;
}

.mobile-nav.active {
    right: 0;
}

.mobile-nav-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 60px;
}

.mobile-nav-list {
    display: flex;
    flex-direction: column;
    gap: 30px;
}

.mobile-nav-link {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-primary);
}

/* Modal Styles */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(15, 23, 42, 0.6);
    backdrop-filter: blur(4px);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 3000;
    padding: 20px;
}

.modal.active {
    display: flex;
}

.modal-content {
    background: #FFFFFF;
    width: 100%;
    max-width: 450px;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
}

.modal-header {
    padding: 20px 24px;
    background: var(--color-background);
    border-bottom: 1px solid var(--color-border);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-header h3 {
    font-size: 1.25rem;
    margin: 0;
}

.modal-close {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--color-secondary);
    line-height: 1;
}

.modal-body {
    padding: 24px;
}

.contact-item {
    display: flex;
    gap: 16px;
    margin-bottom: 20px;
}

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

.contact-item i {
    color: var(--color-accent);
    flex-shrink: 0;
}

.contact-item .label {
    font-size: 0.875rem;
    color: var(--color-secondary);
    margin-bottom: 4px;
    font-weight: 500;
}

.contact-item .value {
    font-size: 1rem;
    color: var(--color-primary);
    font-weight: 600;
}

.modal-footer {
    padding: 20px 24px;
    border-top: 1px solid var(--color-border);
}

/* About Section Timeline */
.timeline {
    position: relative;
    padding-left: 20px;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 0;
    top: 5px;
    bottom: 5px;
    width: 2px;
    background: var(--color-border);
}

.timeline li {
    position: relative;
    padding-bottom: 20px;
}

.timeline li:last-child {
    padding-bottom: 0;
}

.timeline .year {
    font-weight: 800;
    color: var(--color-accent);
    font-size: 0.9rem;
    display: block;
    margin-bottom: 2px;
}

.timeline p {
    font-size: 0.85rem !important;
    margin: 0 !important;
}

.timeline li::after {
    content: '';
    position: absolute;
    left: -24px;
    top: 6px;
    width: 10px;
    height: 10px;
    background: #FFF;
    border: 2px solid var(--color-accent);
    border-radius: 50%;
}

/* Solution Tabs */
.tab-nav-center {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-bottom: 40px;
}

.tab-btn-pill {
    padding: 10px 24px;
    border-radius: 30px;
    border: 1px solid var(--color-border);
    background: #FFF;
    color: var(--color-secondary);
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
}

/* Solution Tabs Pill */
.tab-btn-pill.active {
    background: var(--color-accent);
    border-color: var(--color-accent);
    color: #FFF;
}

.solution-pane {
    display: none;
}

.solution-pane.active {
    display: block;
}

.solution-tag-small {
    display: inline-block;
    padding: 4px 12px;
    background: rgba(37, 99, 235, 0.1);
    color: var(--color-accent);
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 700;
    margin-bottom: 15px;
}

.solution-img-bottom {
    margin-top: 20px;
    border-radius: 8px;
    overflow: hidden;
}

/* System Product Grid */
.system-product-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
}

.system-product-card {
    display: flex;
    gap: 20px;
    padding: 24px;
    background: #FFF;
    border-radius: 12px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease;
}

.system-product-card:hover {
    transform: translateY(-5px);
}

.system-icon {
    flex-shrink: 0;
    width: 48px;
    height: 48px;
    background: var(--color-background);
    color: var(--color-accent);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.system-info h4 {
    margin-bottom: 8px;
}

.product-category-title {
    margin-bottom: 30px;
    border-left: 4px solid var(--color-accent);
    padding-left: 15px;
}

/* Partner Logos */
.partner-logos {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 40px;
    align-items: center;
    justify-items: center;
}

.logo-item {
    text-align: center;
    transition: filter 0.3s ease;
}

.logo-item img {
    width: 80px;
    height: 80px;
    object-fit: contain;
    margin-bottom: 10px;
    filter: grayscale(1);
    opacity: 0.7;
    transition: all 0.3s ease;
}

.logo-item:hover img {
    filter: grayscale(0);
    opacity: 1;
}

.logo-item span {
    display: block;
    font-size: 0.875rem;
    color: var(--color-secondary);
    font-weight: 500;
}

/* Responsive Styles */
@media (max-width: 1024px) {
    .hero-title {
        font-size: 3rem;
    }
    
    .about-grid, .contact-grid {
        grid-template-columns: 1fr;
        gap: 40px;
    }
    
    .product-grid, .news-grid, .solution-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .section-padding {
        padding: var(--mobile-section-padding);
    }
}

@media (max-width: 768px) {
    .nav-desktop {
        display: none;
    }
    
    .mobile-menu-toggle {
        display: block;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-btns {
        flex-direction: column;
    }
    
    .product-grid, .news-grid, .solution-grid {
        grid-template-columns: 1fr;
    }
    
    .footer-bottom {
        flex-direction: column;
        gap: 20px;
        text-align: center;
    }
    
    .footer-links {
        flex-direction: column;
        gap: 10px;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 2rem;
    }
    
    .stat-num {
        font-size: 2rem;
    }
}