/* =========================================
   VARIABLES & RESET
========================================= */
:root {
    --primary: #FFB800;
    --primary-hover: #e0a200;
    --dark-bg: #101820;
    --darker-bg: #0a0f14;
    --light-bg: #ffffff;
    --gray-bg: #f9fafb;
    --text-white: #ffffff;
    --text-light-gray: #d1d5db;
    --text-dark: #1f2937;
    --text-gray: #4b5563;
    --border-color: rgba(255, 255, 255, 0.1);
    --transition: all 0.3s ease;
    --border-radius: 6px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', sans-serif;
}

html {
    scroll-behavior: smooth;
}

body {
    background-color: var(--light-bg);
    color: var(--text-dark);
    line-height: 1.6;
}

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

ul {
    list-style: none;
}

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

/* =========================================
   TYPOGRAPHY & UTILITIES
========================================= */
h1, h2, h3, h4 {
    line-height: 1.2;
    font-weight: 800;
}

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

.subtitle {
    display: block;
    color: var(--primary);
    font-size: 0.875rem;
    font-weight: 700;
    letter-spacing: 1px;
    margin-bottom: 1rem;
    text-transform: uppercase;
}

.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 20px;
}

.section-header {
    text-align: center;
    margin-bottom: 3rem;
    max-width: 700px;
    margin-inline: auto;
}

.section-header h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: var(--dark-bg);
}

.section-header p {
    color: var(--text-gray);
    font-size: 1.125rem;
}

.center-action {
    text-align: center;
    margin-top: 3rem;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.875rem 1.75rem;
    font-weight: 700;
    font-size: 0.875rem;
    border-radius: var(--border-radius);
    cursor: pointer;
    text-transform: uppercase;
    transition: var(--transition);
    border: none;
}

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

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

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

.btn-outline-white {
    background: transparent;
    color: var(--text-white);
    border: 1px solid var(--text-white);
}

.btn-outline-white:hover {
    background: var(--text-white);
    color: var(--dark-bg);
}

.btn-icon, .btn-outline-icon {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--border-radius);
    transition: var(--transition);
}

.btn-icon {
    background-color: var(--primary);
    color: var(--dark-bg);
}

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

.btn-outline-icon {
    border: 1px solid var(--primary);
    color: var(--primary);
}

.project-card:hover .btn-outline-icon {
    background-color: var(--primary);
    color: var(--dark-bg);
}

.w-100 {
    width: 100%;
}

/* Layout Grids */
.grid-2 {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 3rem;
}

.grid-3 {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
}

.grid-4 {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1.5rem;
}

.align-center {
    align-items: center;
}

/* =========================================
   HEADER & NAVBAR
========================================= */
.navbar {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    padding: 1.5rem 0;
    z-index: 100;
    border-bottom: 1px solid var(--border-color);
    background: rgba(16, 24, 32, 0.4);
    backdrop-filter: blur(5px);
}

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

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--text-white);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.logo-icon {
    color: var(--primary);
    font-style: italic;
    letter-spacing: -2px;
}

.nav-links {
    display: flex;
    gap: 2rem;
}

.nav-links a {
    color: var(--text-white);
    font-size: 0.875rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 0.25rem;
}

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

.nav-arrow {
    font-size: 0.6rem;
}

.hamburger {
    display: none;
    color: var(--text-white);
    font-size: 1.5rem;
    cursor: pointer;
}

.mobile-menu {
    display: none;
    flex-direction: column;
    background-color: var(--dark-bg);
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    padding: 1rem 20px;
    border-top: 1px solid var(--border-color);
}

.mobile-menu.active {
    display: flex;
}

.mobile-menu a {
    color: var(--text-white);
    padding: 1rem 0;
    border-bottom: 1px solid var(--border-color);
    font-weight: 600;
}

.mobile-menu a:last-child {
    border-bottom: none;
    margin-top: 1rem;
}

/* =========================================
   HERO SECTION
========================================= */
.hero-section {
    position: relative;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    background: linear-gradient(rgba(16, 24, 32, 0.8), rgba(16, 24, 32, 0.7)), url('/images/Highway-Noise-Control-Highway-Noise-Barriers.webp') center/cover no-repeat;
}

.hero-content {
    flex: 1;
    display: flex;
    align-items: center;
    padding-top: 80px; /* offset for nav */
}

.hero-text h1 {
    color: var(--text-white);
    font-size: 4rem;
    margin-bottom: 1.5rem;
}

.hero-text p {
    color: var(--text-light-gray);
    font-size: 1.25rem;
    margin-bottom: 2.5rem;
}

.hero-bottom-bar {
    background: rgba(16, 24, 32, 0.8);
    backdrop-filter: blur(5px);
    border-top: 1px solid var(--border-color);
    padding: 1.5rem 0;
}

.flex-bar {
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 1.5rem;
}

.feature-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    color: var(--text-white);
}

.icon-circle {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    border: 1px solid rgba(255,255,255,0.3);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
}

.feature-text {
    display: flex;
    flex-direction: column;
}

.feature-text .title {
    font-size: 0.875rem;
    font-weight: 700;
    text-transform: uppercase;
}

.feature-text .desc {
    font-size: 0.75rem;
    color: var(--text-light-gray);
}

/* =========================================
   PRODUCTS SECTION
========================================= */
.products-section {
    padding: 6rem 0;
    background-color: var(--light-bg);
}

.product-card {
    background-color: var(--dark-bg);
    border-radius: var(--border-radius);
    overflow: hidden;
    display: flex;
    flex-direction: column;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    transition: transform 0.3s;
}

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

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

.card-content {
    padding: 2rem;
    display: flex;
    flex-direction: column;
    flex: 1;
}

.card-content h3 {
    color: var(--text-white);
    font-size: 1.25rem;
    margin-bottom: 1rem;
}

.card-content p {
    color: var(--text-light-gray);
    font-size: 0.875rem;
    margin-bottom: 1.5rem;
    flex: 1;
}

/* =========================================
   SOLUTIONS SECTION
========================================= */
.solutions-section {
    padding: 6rem 0;
    background-color: var(--gray-bg);
}

.solution-card {
    position: relative;
    height: 450px;
    border-radius: var(--border-radius);
    overflow: hidden;
    background-size: cover;
    background-position: center;
}

.solution-card .icon-box {
    position: absolute;
    top: 1.5rem;
    left: 1.5rem;
    width: 60px;
    height: 60px;
    background-color: var(--primary);
    color: var(--dark-bg);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.75rem;
    border-radius: var(--border-radius);
    z-index: 2;
}

.overlay-content {
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    padding: 2rem;
    background: linear-gradient(to top, rgba(16,24,32,0.95), rgba(16,24,32,0.7), transparent);
    color: var(--text-white);
}

.overlay-content h3 {
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
}

.overlay-content p {
    font-size: 0.875rem;
    color: var(--text-light-gray);
    margin-bottom: 1rem;
}

.link-yellow {
    color: var(--primary);
    font-weight: 700;
    font-size: 0.875rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

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

/* =========================================
   WHY CHOOSE US SECTION
========================================= */
.about-section {
    padding: 6rem 0;
    background-color: var(--light-bg);
}

.about-text h2 {
    font-size: 2.5rem;
    margin-bottom: 1.5rem;
}

.about-text > p {
    font-size: 1.125rem;
    color: var(--text-gray);
    margin-bottom: 2.5rem;
}

.feature-list {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.feature-list li {
    display: flex;
    gap: 1.25rem;
}

.list-icon {
    width: 50px;
    height: 50px;
    background-color: rgba(255, 184, 0, 0.1);
    color: var(--primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    flex-shrink: 0;
}

.list-text strong {
    display: block;
    font-size: 1.125rem;
    color: var(--dark-bg);
    margin-bottom: 0.25rem;
}

.list-text p {
    color: var(--text-gray);
    font-size: 0.875rem;
}

.about-image {
    position: relative;
}

.about-image img {
    border-radius: var(--border-radius);
    height: 500px;
    object-fit: cover;
    width: 100%;
}

.image-overlay-box {
    position: absolute;
    bottom: -2rem;
    left: -2rem;
    background-color: var(--dark-bg);
    padding: 1.5rem;
    border-radius: var(--border-radius);
    display: flex;
    align-items: center;
    gap: 1rem;
    max-width: 350px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.15);
}

.check-icon {
    width: 50px;
    height: 50px;
    border: 2px solid var(--primary);
    color: var(--primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    flex-shrink: 0;
}

.image-overlay-box strong {
    color: var(--text-white);
    display: block;
    margin-bottom: 0.25rem;
}

.image-overlay-box p {
    color: var(--text-light-gray);
    font-size: 0.75rem;
}

/* Stats Bar below About */
.stats-bar {
    background-color: var(--dark-bg);
    padding: 4rem 0;
    margin-top: 4rem;
}

.stat-item {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    color: var(--text-white);
}

.stat-item i {
    font-size: 2.5rem;
    color: var(--primary);
}

.stat-item .number {
    display: block;
    font-size: 2.5rem;
    font-weight: 800;
    color: var(--primary);
    line-height: 1;
    margin-bottom: 0.5rem;
}

.stat-item .label {
    display: block;
    font-weight: 700;
    font-size: 1rem;
}

.stat-item .sub-label {
    font-size: 0.875rem;
    color: var(--text-light-gray);
}

/* =========================================
   PROJECTS SECTION
========================================= */
.projects-section {
    padding: 6rem 0;
    background-color: var(--gray-bg);
}

.project-card {
    position: relative;
    height: 300px;
    border-radius: var(--border-radius);
    overflow: hidden;
    background-size: cover;
    background-position: center;
}

.project-info {
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    padding: 1.5rem;
    background: linear-gradient(to top, rgba(16,24,32,0.95), transparent);
    color: var(--text-white);
    display: flex;
    justify-content: space-between;
    align-items: flex-end;
}

.project-info .category {
    color: var(--primary);
    font-size: 0.75rem;
    font-weight: 700;
    margin-bottom: 0.25rem;
    display: block;
}

.project-info h3 {
    font-size: 1.25rem;
    margin-bottom: 0.25rem;
}

.project-info .location {
    font-size: 0.75rem;
    color: var(--text-light-gray);
}

/* =========================================
   CONTACT & FORM SECTION
========================================= */
.contact-section {
    padding: 6rem 0;
    background: linear-gradient(rgba(16, 24, 32, 0.9), rgba(16, 24, 32, 0.9)), url('/images/8ee99c559737e74e49a3d02186451155.jpg') center/cover;
    color: var(--text-white);
}

.contact-text h2 {
    font-size: 3rem;
    margin-bottom: 1.5rem;
}

.contact-text > p {
    color: var(--text-light-gray);
    font-size: 1.125rem;
    margin-bottom: 2rem;
}

.btn-group {
    display: flex;
    gap: 1rem;
    margin-bottom: 2.5rem;
    flex-wrap: wrap;
}

.contact-info {
    display: flex;
    align-items: center;
    gap: 1.5rem;
    font-size: 1.125rem;
    flex-wrap: wrap;
}

.contact-info i {
    color: var(--primary);
    margin-right: 0.5rem;
}

.contact-info .divider {
    width: 1px;
    height: 20px;
    background-color: var(--text-gray);
}

.contact-form-card {
    background-color: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border-color);
    padding: 2.5rem;
    border-radius: var(--border-radius);
    backdrop-filter: blur(10px);
}

.contact-form-card h3 {
    font-size: 1.75rem;
    margin-bottom: 0.5rem;
}

.contact-form-card p {
    color: var(--text-light-gray);
    margin-bottom: 2rem;
    font-size: 0.875rem;
}

.contact-form-card form {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.form-row {
    display: flex;
    gap: 1rem;
}

.contact-form-card input,
.contact-form-card select,
.contact-form-card textarea {
    width: 100%;
    padding: 1rem;
    background-color: var(--darker-bg);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    color: var(--text-white);
    font-size: 0.875rem;
}

.contact-form-card input:focus,
.contact-form-card select:focus,
.contact-form-card textarea:focus {
    outline: none;
    border-color: var(--primary);
}

.contact-form-card button {
    margin-top: 1rem;
}

/* =========================================
   FOOTER SECTION
========================================= */
footer {
    background-color: var(--dark-bg);
    color: var(--text-light-gray);
    padding-top: 4rem;
}

.footer-cta {
    background: linear-gradient(135deg, var(--darker-bg) 0%, var(--dark-bg) 100%);
    border: 1px solid var(--primary);
    border-radius: var(--border-radius);
    padding: 2.5rem 3rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 4rem;
    flex-wrap: wrap;
    gap: 2rem;
}

.cta-text h2 {
    color: var(--text-white);
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.cta-btns {
    display: flex;
    gap: 1rem;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1.5fr;
    gap: 2rem;
    margin-bottom: 4rem;
}

.brand-col .logo {
    margin-bottom: 1.5rem;
}

.brand-col p {
    margin-bottom: 1.5rem;
    font-size: 0.875rem;
}

.mini-stats {
    display: flex;
    gap: 1.5rem;
}

.mini-stats div {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.875rem;
    color: var(--text-white);
}

.mini-stats i {
    color: var(--primary);
    font-size: 1.25rem;
}

.footer-col h4 {
    color: var(--text-white);
    margin-bottom: 1.5rem;
    font-size: 1rem;
}

.footer-col ul {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.footer-col ul li a {
    font-size: 0.875rem;
}

.footer-col ul li a:hover {
    color: var(--primary);
}

.contact-details li {
    display: flex;
    gap: 1rem;
    align-items: flex-start;
    font-size: 0.875rem;
}

.contact-details i {
    color: var(--primary);
    margin-top: 0.25rem;
}

.social-links {
    display: flex;
    gap: 1rem;
    margin-top: 1.5rem;
}

.social-links a {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    border: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-light-gray);
}

.social-links a:hover {
    background-color: var(--primary);
    color: var(--dark-bg);
    border-color: var(--primary);
}

.footer-bottom {
    border-top: 1px solid var(--border-color);
    padding: 2rem 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.875rem;
    flex-wrap: wrap;
    gap: 1rem;
}

.legal-links .divider {
    margin: 0 0.5rem;
}

/* =========================================
   MEDIA QUERIES (RESPONSIVE)
========================================= */
@media (max-width: 1024px) {
    .grid-4, .grid-3 {
        grid-template-columns: repeat(2, 1fr);
    }

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

    .hero-text h1 {
        font-size: 3rem;
    }
}

@media (max-width: 992px) {
    .nav-links, .nav-actions {
        display: none;
    }

    .hamburger {
        display: block;
    }

    .grid-2 {
        grid-template-columns: 1fr;
    }

    .about-image .image-overlay-box {
        left: 50%;
        transform: translateX(-50%);
        bottom: -3rem;
        width: 90%;
    }

    .contact-form-card {
        margin-top: 2rem;
    }
}

@media (max-width: 768px) {
    .hero-text h1 {
        font-size: 2.5rem;
    }

    .flex-bar {
        flex-direction: column;
        align-items: flex-start;
    }

    .form-row {
        flex-direction: column;
    }

    .stats-bar .grid-4 {
        grid-template-columns: repeat(2, 1fr);
        gap: 2rem;
    }

    .footer-cta {
        flex-direction: column;
        text-align: center;
    }

    .footer-bottom {
        flex-direction: column;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .grid-4, .grid-3 {
        grid-template-columns: 1fr;
    }

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

    .stats-bar .grid-4 {
        grid-template-columns: 1fr;
    }

    .btn-group {
        flex-direction: column;
        width: 100%;
    }

    .contact-info .divider {
        display: none;
    }
}

/* ==========================================
   右侧悬浮联系侧边栏 (Floating Sidebar)
   ========================================== */

.floating-sidebar {
    position: fixed;
    right: 0;
    top: 50%;
    transform: translateY(-50%);
    z-index: 9999;
    display: flex;
    flex-direction: column;
    gap: 1px; /* 图标之间的细微缝隙 */
    box-shadow: -2px 0 10px rgba(0, 0, 0, 0.1);
}

.sidebar-item {
    position: relative;
    width: 50px;
    height: 50px;
    background-color: #111827; /* 默认深色背景 */
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.3s ease;
}

.sidebar-item a {
    color: #ffffff;
    font-size: 24px;
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    text-decoration: none;
    transition: all 0.3s ease;
}

.sidebar-item:not(.whatsapp):not(.telegram):not(.email):not(.back-to-top) i {
    color: #fff;
}

/* 按钮图标默认颜色 */
.sidebar-item i {
    color: #ffffff;
    font-size: 20px;
}

/* 鼠标悬浮时的品牌色高亮 */
.sidebar-item.whatsapp:hover { background-color: #25D366; } /* WhatsApp 绿 */
.sidebar-item.telegram:hover { background-color: #229ED9; } /* Telegram 蓝 */
.sidebar-item.email:hover { background-color: #FBBF24; }    /* 您的主题黄 */
.sidebar-item.back-to-top:hover { background-color: #4b5563; } /* 返回顶部灰色高亮 */

/* 悬浮提示框 (Tooltip) 的通用样式 */
.sidebar-tooltip {
    position: absolute;
    right: 60px; /* 从右侧往左弹出的距离 */
    top: 50%;
    transform: translateY(-50%) translateX(20px);
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s cubic-bezier(0.68, -0.55, 0.265, 1.55); /* 弹性动画 */
    pointer-events: none; /* 防止遮挡鼠标 */
    z-index: 10000;
}

/* 鼠标移入时显示 Tooltip */
.sidebar-item:hover .sidebar-tooltip {
    opacity: 1;
    visibility: visible;
    transform: translateY(-50%) translateX(0);
}

/* 带有二维码的提示框样式 */
.qr-tooltip {
    background-color: #ffffff;
    padding: 10px;
    border-radius: 8px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.15);
    border: 1px solid #e5e7eb;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
}

.qr-tooltip img {
    width: 120px; /* 二维码大小 */
    height: 120px;
    object-fit: contain;
}

.qr-tooltip span {
    font-size: 13px;
    font-weight: bold;
    color: #374151;
}

/* 纯文本提示框（邮箱）样式 */
.text-tooltip {
    background-color: #FBBF24; /* 匹配邮件悬浮主题色 */
    color: #111827;
    font-weight: bold;
    padding: 12px 16px;
    border-radius: 6px;
    white-space: nowrap; /* 保证邮箱不换行 */
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

/* 文本提示框的小三角形箭头 */
.text-tooltip::after, .qr-tooltip::after {
    content: '';
    position: absolute;
    top: 50%;
    right: -6px;
    transform: translateY(-50%);
    border-width: 6px 0 6px 6px;
    border-style: solid;
}
.text-tooltip::after { border-color: transparent transparent transparent #FBBF24; }
.qr-tooltip::after { border-color: transparent transparent transparent #ffffff; }

/* ==========================================
   移动端优化 方案二：底部横向固定吸底
   ========================================== */
@media screen and (max-width: 768px) {
    /* 1. 彻底隐藏悬浮二维码和文字提示 */
    .sidebar-tooltip,
    .qr-tooltip,
    .text-tooltip {
        display: none !important;
    }

    /* 2. 将竖排改为底部横排，宽度100%吸底 */
    .floating-sidebar {
        top: auto;
        bottom: 0;
        left: 0;
        right: 0;
        width: 100%;
        transform: none;
        flex-direction: row;
        box-shadow: 0 -2px 10px rgba(0,0,0,0.1);
        z-index: 99999;
    }

    /* 3. 按钮平分底部宽度，增大点击区域 */
    .sidebar-item {
        flex: 1; /* 四个按钮各占 25% 宽度 */
        height: 55px;
        border-right: 1px solid rgba(255,255,255,0.1); /* 按钮之间的暗色分割线 */
    }

    .sidebar-item:last-child {
        border-right: none;
    }

    .sidebar-item i {
        font-size: 22px;
    }

    /* 为防止底部按钮遮挡网页最下方的内容，给手机端 body 增加底部内边距 */
    body {
        padding-bottom: 60px !important;
    }
}