/* ========================================
   粉末喷涂企业门户网站 - 样式表
   主色调：深蓝色系 (#1a365d, #2c5282)
   辅助色：橙色 (#ed8936) 用于强调
   ======================================== */

/* 基础重置与变量 */
:root {
    --primary: #1a365d;
    --primary-light: #2c5282;
    --primary-dark: #0f2744;
    --accent: #ed8936;
    --accent-hover: #dd6b20;
    --text: #2d3748;
    --text-light: #718096;
    --text-lighter: #a0aec0;
    --bg: #ffffff;
    --bg-light: #f7fafc;
    --bg-dark: #edf2f7;
    --border: #e2e8f0;
    --shadow: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -1px rgba(0,0,0,0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1), 0 4px 6px -2px rgba(0,0,0,0.05);
    --transition: all 0.3s ease;
    --radius: 8px;
    --radius-lg: 12px;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
    color: var(--text);
    line-height: 1.6;
    background: var(--bg);
}

/* 确保图片有明确宽高，防止 CLS */
img {
    max-width: 100%;
    height: auto;
    display: block;
}

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

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

ul {
    list-style: none;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* ========================================
   按钮样式
   ======================================== */
.btn-primary {
    display: inline-block;
    padding: 12px 32px;
    background: var(--accent);
    color: #fff;
    border-radius: var(--radius);
    font-weight: 500;
    font-size: 15px;
    transition: var(--transition);
    border: none;
    cursor: pointer;
}

.btn-primary:hover {
    background: var(--accent-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-outline {
    display: inline-block;
    padding: 10px 28px;
    background: transparent;
    color: var(--primary);
    border: 2px solid var(--primary);
    border-radius: var(--radius);
    font-weight: 500;
    font-size: 14px;
    transition: var(--transition);
}

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

.btn-large {
    padding: 16px 48px;
    font-size: 16px;
}

/* ========================================
   顶部信息栏
   ======================================== */
.top-bar {
    background: var(--primary-dark);
    color: rgba(255,255,255,0.85);
    font-size: 13px;
    padding: 8px 0;
}

.top-bar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.top-bar i {
    margin-right: 6px;
    color: var(--accent);
}

/* ========================================
   导航栏
   ======================================== */
.header {
    background: var(--bg);
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 1000;
    transition: var(--transition);
}

.header.scrolled {
    box-shadow: 0 4px 20px rgba(0,0,0,0.1);
}

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

.logo a {
    display: flex;
    align-items: center;
    gap: 12px;
}

.logo-icon {
    height: 48px;
    width: auto;
    display: block;
}

.logo-icon {
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, var(--primary), var(--primary-light));
    justify-content: center;
    color: #fff;
    font-size: 22px;
}

.logo-text h1 {
    font-size: 20px;
    font-weight: 700;
    color: var(--primary);
    line-height: 1.2;
}

.logo-text p {
    font-size: 12px;
    color: var(--text-light);
    margin-top: 2px;
}

.nav ul {
    display: flex;
    gap: 36px;
}

.nav a {
    font-size: 15px;
    font-weight: 500;
    color: var(--text);
    position: relative;
    padding: 8px 0;
}

.nav a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent);
    transition: var(--transition);
}

.nav a:hover::after,
.nav li.active a::after {
    width: 100%;
}

.nav a:hover,
.nav li.active a {
    color: var(--primary);
}

.mobile-menu-btn {
    display: none;
    font-size: 24px;
    color: var(--primary);
    cursor: pointer;
}

/* ========================================
   Banner轮播
   ======================================== */
.banner {
    position: relative;
    height: 600px;
    overflow: hidden;
}

.banner-slide {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-size: cover;
    background-position: center;
    opacity: 0;
    transition: opacity 1s ease;
}

.banner-slide.active {
    opacity: 1;
}

.banner-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, rgba(26,54,93,0.85) 0%, rgba(26,54,93,0.6) 100%);
}

.banner-content {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
    color: #fff;
    z-index: 2;
    width: 90%;
    max-width: 800px;
}

.banner-content h2 {
    font-size: 48px;
    font-weight: 700;
    margin-bottom: 16px;
    text-shadow: 0 2px 10px rgba(0,0,0,0.3);
    animation: fadeInUp 1s ease;
}

.banner-content p {
    font-size: 20px;
    margin-bottom: 32px;
    opacity: 0.9;
    animation: fadeInUp 1s ease 0.2s both;
}

.banner-content .btn-primary {
    animation: fadeInUp 1s ease 0.4s both;
}

.banner-dots {
    position: absolute;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    gap: 10px;
    z-index: 3;
}

.dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: rgba(255,255,255,0.4);
    cursor: pointer;
    transition: var(--transition);
}

.dot.active {
    background: var(--accent);
    transform: scale(1.2);
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ========================================
   区块标题
   ======================================== */
.section-header {
    text-align: center;
    margin-bottom: 50px;
}

.section-header.left {
    text-align: left;
}

.section-header.light h3 span,
.section-header.light p {
    color: #fff;
}

.section-header.light h3 i {
    color: rgba(255,255,255,0.5);
}

.section-header h3 {
    margin-bottom: 12px;
}

.section-header h3 span {
    display: block;
    font-size: 32px;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 4px;
}

.section-header h3 i {
    font-size: 14px;
    color: var(--text-lighter);
    font-style: normal;
    letter-spacing: 2px;
}

.section-header p {
    color: var(--text-light);
    font-size: 16px;
}

/* ========================================
   服务领域
   ======================================== */
.services {
    padding: 80px 0;
    background: var(--bg);
}

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

@media (max-width: 1200px) {
    .services-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

.service-card {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 36px 24px;
    text-align: center;
    transition: var(--transition);
}

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

.service-icon {
    width: 72px;
    height: 72px;
    background: linear-gradient(135deg, var(--primary), var(--primary-light));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 20px;
    color: #fff;
    font-size: 28px;
    transition: var(--transition);
    will-change: transform;
}

.service-card:hover .service-icon {
    transform: rotate(360deg);
}

.service-card h4 {
    font-size: 18px;
    font-weight: 600;
    color: var(--primary);
    margin-bottom: 12px;
}

.service-card p {
    font-size: 14px;
    color: var(--text-light);
    line-height: 1.7;
    margin-bottom: 16px;
}

.service-link {
    font-size: 14px;
    color: var(--accent);
    font-weight: 500;
}

.service-link i {
    margin-left: 4px;
    transition: var(--transition);
}

.service-link:hover i {
    transform: translateX(4px);
}

/* ========================================
   关于我们
   ======================================== */
.about {
    padding: 80px 0;
    background: var(--bg-light);
}

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

.about-desc {
    color: var(--text-light);
    line-height: 1.8;
    margin-bottom: 16px;
}

.about-features {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
    margin: 24px 0;
}

.feature-item {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 14px;
    color: var(--text);
}

.feature-item i {
    color: #48bb78;
    font-size: 16px;
}

.about-image {
    position: relative;
}

.about-image img {
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
}

.experience-badge {
    position: absolute;
    bottom: -20px;
    right: -20px;
    background: var(--accent);
    color: #fff;
    padding: 20px 28px;
    border-radius: var(--radius-lg);
    text-align: center;
    box-shadow: var(--shadow-lg);
}

.experience-badge .years {
    display: block;
    font-size: 36px;
    font-weight: 700;
    line-height: 1;
}

.experience-badge .text {
    font-size: 13px;
    opacity: 0.9;
}

/* ========================================
   核心优势
   ======================================== */
.advantages {
    padding: 80px 0;
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-light) 100%);
    color: #fff;
}

.advantages-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 30px;
}

.advantage-item {
    background: rgba(255,255,255,0.08);
    border: 1px solid rgba(255,255,255,0.15);
    border-radius: var(--radius-lg);
    padding: 36px 24px;
    text-align: center;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
    will-change: transform;
}

.advantage-item:hover {
    background: rgba(255,255,255,0.15);
    transform: translateY(-5px);
}

.advantage-num {
    position: absolute;
    top: 10px;
    right: 16px;
    font-size: 48px;
    font-weight: 700;
    color: rgba(255,255,255,0.08);
    line-height: 1;
}

.advantage-icon {
    width: 64px;
    height: 64px;
    background: var(--accent);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 20px;
    font-size: 24px;
}

.advantage-item h4 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 12px;
}

.advantage-item p {
    font-size: 14px;
    line-height: 1.7;
    opacity: 0.85;
}

/* ========================================
   工艺流程
   ======================================== */
.process {
    padding: 80px 0;
    background: var(--bg);
}

.process-steps {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 20px;
    flex-wrap: wrap;
}

.process-step {
    text-align: center;
    flex: 1;
    min-width: 180px;
    max-width: 220px;
}

.step-icon {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, var(--primary), var(--primary-light));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 16px;
    color: #fff;
    font-size: 28px;
    position: relative;
}

.step-num {
    top: -5px;
    right: -5px;
    width: 28px;
    height: 28px;
    background: var(--accent);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 13px;
    font-weight: 600;
}

.process-step h4 {
    font-size: 17px;
    font-weight: 600;
    color: var(--primary);
    margin-bottom: 6px;
}

.process-step p {
    font-size: 13px;
    color: var(--text-light);
}

.process-arrow {
    color: var(--accent);
    font-size: 24px;
    flex-shrink: 0;
}

/* ========================================
   案例展示
   ======================================== */
.cases {
    padding: 80px 0;
    background: var(--bg-light);
}

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

.case-item {
    background: var(--bg);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: var(--transition);
    will-change: transform;
}

.case-item:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.case-image {
    position: relative;
    overflow: hidden;
    height: 200px;
}

.case-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: var(--transition);
}

.case-item:hover .case-image img {
    transform: scale(1.1);
}

.case-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(to top, rgba(26,54,93,0.7) 0%, transparent 50%);
    display: flex;
    align-items: flex-end;
    padding: 16px;
}

.case-tag {
    background: var(--accent);
    color: #fff;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 500;
}

.case-info {
    padding: 20px;
}

.case-info h4 {
    font-size: 16px;
    font-weight: 600;
    color: var(--primary);
    margin-bottom: 6px;
}

.case-info p {
    font-size: 13px;
    color: var(--text-light);
}

/* ========================================
   合作伙伴
   ======================================== */
.partners-section {
    padding: 80px 0;
    background: var(--bg);
}

.partners-row {
    display: flex;
    align-items: center;
    justify-content: center;
    flex-wrap: wrap;
    gap: 24px;
}

.partner-logo-box {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 220px;
    height: 100px;
    background: #fff;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 16px 24px;
    transition: var(--transition);
    text-decoration: none;
}

.partner-logo-box:hover {
    border-color: var(--accent);
    box-shadow: 0 4px 12px rgba(237, 137, 54, 0.15);
    transform: translateY(-3px);
}

.partner-logo-box img {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
    filter: grayscale(30%);
    transition: var(--transition);
}

.partner-logo-box:hover img {
    filter: grayscale(0%);
}

@media (max-width: 768px) {
    .partners-row {
        gap: 16px;
    }

    .partner-logo-box {
        width: 160px;
        height: 80px;
        padding: 12px 16px;
    }
}

/* ========================================
   联系我们区块
   ======================================== */
.contact-section {
    padding: 60px 0;
    background: linear-gradient(135deg, var(--primary-dark) 0%, var(--primary) 100%);
    color: #fff;
}

.contact-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 40px;
}

.contact-text h3 {
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 8px;
}

.contact-text > p {
    opacity: 0.85;
    margin-bottom: 24px;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.info-item {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 15px;
}

.info-item i {
    color: var(--accent);
    font-size: 16px;
    width: 20px;
}

.contact-cta {
    flex-shrink: 0;
}

/* ========================================
   页脚
   ======================================== */
.footer {
    background: var(--primary-dark);
    color: rgba(255,255,255,0.7);
    padding: 60px 0 0;
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr 1.5fr;
    gap: 32px;
    padding-bottom: 40px;
    border-bottom: 1px solid rgba(255,255,255,0.1);
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 20px;
    font-weight: 700;
    color: #fff;
    margin-bottom: 16px;
}

.logo-icon {
    height: 36px;
    width: auto;
    display: block;
}

.footer-logo i {
    color: var(--accent);
    font-size: 24px;
}

.footer-brand p {
    font-size: 14px;
    line-height: 1.7;
}

.footer-links h4,
.footer-contact h4 {
    font-size: 16px;
    font-weight: 600;
    color: #fff;
    margin-bottom: 20px;
}

.footer-links ul {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.footer-links a {
    font-size: 14px;
    transition: var(--transition);
}

.footer-links a:hover {
    color: var(--accent);
    padding-left: 4px;
}

.footer-contact p {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 14px;
    margin-bottom: 10px;
}

.footer-contact i {
    color: var(--accent);
    width: 16px;
}

.footer-bottom {
    padding: 20px 0;
    text-align: center;
    font-size: 13px;
}

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

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

/* ========================================
   文章卡片（首页技术资讯区块）
   ======================================== */
.articles-section {
    padding: 80px 0;
    background: var(--bg-light);
}

.articles-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.article-card {
    background: #fff;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 2px 8px rgba(0,0,0,0.08);
    transition: all 0.3s ease;
    border: 1px solid #e2e8f0;
    text-decoration: none;
    color: inherit;
    display: flex;
    flex-direction: column;
}

.article-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 12px 24px rgba(0,0,0,0.12);
    border-color: transparent;
}

.article-card-image {
    height: 160px;
    background: linear-gradient(135deg, #1a365d 0%, #2c5282 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-size: 40px;
}

.article-card-content {
    padding: 20px;
    flex: 1;
    display: flex;
    flex-direction: column;
}

.article-card-content h3 {
    font-size: 17px;
    font-weight: 600;
    color: #1a365d;
    margin-bottom: 10px;
    line-height: 1.4;
}

.article-card:hover .article-card-content h3 {
    color: #ed8936;
}

.article-card-content p {
    font-size: 14px;
    color: #718096;
    line-height: 1.6;
    flex: 1;
    margin-bottom: 14px;
}

.article-card-meta {
    display: flex;
    gap: 16px;
    font-size: 12px;
    color: #a0aec0;
}

.article-card-meta i {
    margin-right: 4px;
}

.articles-more {
    text-align: center;
    margin-top: 40px;
}

/* ========================================
   回到顶部
   ======================================== */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 48px;
    height: 48px;
    background: var(--accent);
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
    z-index: 999;
    box-shadow: var(--shadow-lg);
}

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

.back-to-top:hover {
    background: var(--accent-hover);
    transform: translateY(-3px);
}

/* ========================================
   响应式设计
   ======================================== */
@media (max-width: 1024px) {
    .services-grid,
    .advantages-grid,
    .cases-grid,
    .articles-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .footer-content {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .top-bar .container {
        flex-direction: column;
        gap: 4px;
        text-align: center;
    }
    
    .nav {
        display: none;
    }
    
    .mobile-menu-btn {
        display: block;
    }
    
    .banner {
        height: 450px;
    }
    
    .banner-content h2 {
        font-size: 32px;
    }
    
    .banner-content p {
        font-size: 16px;
    }
    
    .services-grid,
    .advantages-grid,
    .cases-grid,
    .articles-grid {
        grid-template-columns: 1fr;
    }
    
    .about-content {
        grid-template-columns: 1fr;
        gap: 40px;
    }
    
    .about-image {
        order: -1;
    }
    
    .experience-badge {
        right: 10px;
        bottom: -10px;
    }
    
    .process-steps {
        flex-direction: column;
    }
    
    .process-arrow {
        transform: rotate(90deg);
    }
    
    .contact-content {
        flex-direction: column;
        text-align: center;
    }
    
    .contact-info {
        align-items: center;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .footer-logo {
        justify-content: center;
    }
    
    .footer-contact p {
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .section-header h3 span {
        font-size: 24px;
    }
    
    .banner {
        height: 380px;
    }
    
    .banner-content h2 {
        font-size: 26px;
    }
    
    .experience-badge .years {
        font-size: 28px;
    }
}