/* ============================================
   Sea Link Solutions - Main Stylesheet
   ============================================ */

/* CSS Variables */
:root {
    --color-bg: #0a0e1a;
    --color-bg-light: #0f1629;
    --color-bg-card: #111827;
    --color-orange: #ff6b00;
    --color-orange-light: #ff8533;
    --color-orange-dark: #e65c00;
    --color-text: #ffffff;
    --color-text-muted: #b0b0b0;
    --color-text-dark: #808080;
    --color-border: rgba(255, 255, 255, 0.2);
    --font-heading: 'Playfair Display', Georgia, serif;
    --font-body: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --transition: all 0.3s ease;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-body);
    background-color: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
}

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

a {
    color: inherit;
    text-decoration: none;
}

ul {
    list-style: none;
}

h1, h2, h3, h4, h5, p {
    cursor: default;
}

/* Container */
.container {
    width: 100%;
    max-width: 80rem;
    margin: 0 auto;
    padding: 0 5.5rem;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.75rem;
    font-family: var(--font-body);
    font-size: 0.875rem;
    font-weight: 500;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    border: none;
    cursor: pointer;
    transition: var(--transition);
    border-radius: 2px;
}

.btn-primary {
    background: linear-gradient(135deg, var(--color-orange) 0%, var(--color-orange-light) 50%, var(--color-orange) 100%);
    background-size: 200% 200%;
    color: var(--color-bg);
    transition: all 0.5s ease, filter 0.3s ease;
}

.btn-primary:hover {
    background-position: 100% 100%;
    filter: brightness(1.15);
    border-radius: 1rem;
}

.btn-quote {
    background-color: transparent;
    color: var(--color-orange);
    border: 1px solid var(--color-orange);
    padding: 0.5rem 1.25rem;
    border-radius: 2px;
    transition: border-radius 0.4s ease, background-color 0.4s ease, color 0.4s ease;
}

.btn-quote:hover,
.btn-quote.active {
    border-radius: 20px;
    background-color: rgba(255, 107, 0, 0.15);
    color: var(--color-orange-light);
}
.btn-quote:after {
    content: '';
    height: 0 !important;
}

/* ============================================
   Header
   ============================================ */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(10, 14, 26, 0.9);
    backdrop-filter: blur(10px);
    transition: background 0.3s ease, box-shadow 0.3s ease;
}

.header.scrolled {
    background: rgba(10, 14, 26, 0.98);
    box-shadow: var(--shadow);
}

.header-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 4.5rem;
}

.logo {
    display: flex;
    align-items: center;
}

.logo-img {
    width: auto;
    height: 3.5rem;
    object-fit: contain;
}

.logo-text {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
}

.logo-main {
    font-family: var(--font-heading);
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--color-text);
    line-height: 1;
    letter-spacing: 0.1em;
}

.logo-sub {
    font-size: 0.5rem;
    font-weight: 500;
    letter-spacing: 0.2em;
    color: var(--color-text);
    text-transform: uppercase;
    margin-top: 0.125rem;
}

.nav-list {
    display: flex;
    align-items: center;
    gap: 2rem;
}

.nav-list a {
    font-size: 1rem;
    font-weight: 400;
    color: var(--color-text);
    position: relative;
}

.nav-list a:hover::after {
    width: 100%;
}

.nav-list a:hover {
    color: var(--color-orange);
}

.lang-switcher {
    display: flex;
    align-items: center;
    gap: 0.25rem;
    margin-left: 0.5rem;
}

.lang-btn {
    background: none;
    border: none;
    color: var(--color-text);
    font-size: 0.75rem;
    font-weight: 500;
    cursor: pointer;
    padding: 0.25rem;
    transition: var(--transition);
}

.lang-btn.active,
.lang-btn:hover {
    color: var(--color-orange);
}

.lang-divider {
    color: var(--color-text);
    font-size: 0.75rem;
}

.mobile-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

.mobile-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background-color: var(--color-text);
    transition: var(--transition);
}

/* ============================================
   Hero Section
   ============================================ */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    inset: 0;
    z-index: 0;
    background: linear-gradient(135deg, #0f1629 0%, #1a2744 50%, #0a0e1a 100%);
}

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

.hero-img.img-error {
    display: none;
}

.hero-overlay {
    position: absolute;
    inset: 0;
}

.hero-content {
    position: relative;
    z-index: 1;
    padding-top: 4.5rem;
}

.hero-title {
    font-family: var(--font-heading);
    font-size: 4rem;
    font-weight: 600;
    line-height: 1.15;
    color: var(--color-text);
    margin-bottom: 1.5rem;
}

.hero-subtitle {
    font-family: var(--font-heading);
    font-size: 1.325rem;
    font-weight: 300;
    color: var(--color-text);
    margin-bottom: 2.5rem;
    letter-spacing: 0.1em;
}

/* ============================================
   Services Section
   ============================================ */
.services-container {
    max-width: unset;
}
section:nth-child(odd) {
    padding: 6rem 0;
    background: linear-gradient(90deg, var(--color-bg-light), var(--color-bg), var(--color-bg-light));
    background-size: 200%;
    animation: gradientShift 3s ease-in infinite;
}
section:nth-child(even) {
    padding: 6rem 0;
    background: linear-gradient(90deg, var(--color-bg), var(--color-bg-light), var(--color-bg));
    background-size: 200%;
    animation: gradientShift 3s ease-in-out infinite;
}

@keyframes gradientShift {
    0% { background-position: 0%; }
    100% { background-position: 200%; }
}

.section-title {
    cursor: default;
    font-family: var(--font-heading);
    letter-spacing: 0.2rem;
    font-size: 2.25rem;
    font-weight: 400;
    color: var(--color-text);
    text-align: center;
    margin-bottom: 3rem;
    animation: fadeInUp 0.8s ease forwards;
    transition: all 0.6s ease;
}

.section-title:hover,
.section-label:hover {
    text-shadow: 4px 6px 8px rgb(212 117 49);
    transition: all 0.6s ease;
}

/* 文字出现动画 */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* 文字渐变效果 */
@keyframes textGradient {
    0%, 100% {
        background-position: 0% 50%;
    }
    50% {
        background-position: 100% 50%;
    }
}

/* Hero标题特殊效果 */
.hero-title {
    display: inline-block;
    background-image: linear-gradient(to right, 
    var(--color-orange), 
    var(--color-orange) 25%, 
    var(--color-orange) 50%, 
    var(--color-orange) 75%, 
    var(--color-orange));
    -webkit-text-fill-color: transparent;
    -webkit-background-clip: text;
    -webkit-background-size: 200% 100%;
}

/* 段落文字字母间距动画 */
.about-text,
.network-desc {
    letter-spacing: 0.02em;
}

.about-text:hover,
.network-desc:hover {
    letter-spacing: 0.04em;
}

/* 服务卡片文字增强 */
.service-name {
    position: relative;
    display: inline-block;
}

.service-name::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 50%;
    width: 0;
    height: 2px;
    background: var(--color-orange);
    transition: all 0.3s ease;
    transform: translateX(-50%);
}

.service-card:hover .service-name::after {
    width: 100%;
}

@keyframes fadeInLeft {
    from {
        opacity: 0;
        transform: translateX(-30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

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

@keyframes scaleIn {
    from {
        opacity: 0;
        transform: scale(0.9);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

/* 应用动画到各个元素 */
.hero-title {
    animation: fadeInUp 1s ease forwards;
    animation-delay: 0.2s;
    opacity: 0;
}

.hero-subtitle {
    animation: fadeInUp 1s ease forwards;
    animation-delay: 0.4s;
    opacity: 0;
}

.hero .btn {
    animation: fadeInUp 1s ease forwards;
    animation-delay: 0.6s;
    opacity: 0;
}

/* 服务卡片文字动画 */
.service-card {
    animation: scaleIn 0.6s ease forwards;
    opacity: 0;
}

.service-card:nth-child(1) { animation-delay: 0.1s; }
.service-card:nth-child(2) { animation-delay: 0.2s; }
.service-card:nth-child(3) { animation-delay: 0.3s; }
.service-card:nth-child(4) { animation-delay: 0.4s; }

.service-name {
    transition: all 0.3s ease;
}

.service-card:hover .service-name {
    color: var(--color-orange);
    text-shadow: 0 2px 8px rgba(255, 107, 0, 0.4);
}

.service-desc {
    transition: all 0.3s ease;
}

.service-card:hover .service-desc {
    color: var(--color-text);
}

/* 段落文字悬停效果 */
.about-text,
.network-desc,
.features-list li {
    transition: all 0.3s ease;
}

.about-text:hover,
.network-desc:hover {
    transform: translateX(5px);
    color: var(--color-text);
}

.features-list li:hover {
    transform: translateX(8px);
    color: var(--color-orange);
}

/* 导航链接悬停增强 */
.nav-list a {
    position: relative;
    overflow: hidden;
}

.nav-list a::after {
    content: '';
    position: absolute;
    bottom: -0.5rem;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--color-orange);
    transition: width 0.3s ease;
}

.nav-list a:hover::after {
    width: 100%;
}

/* 城市列表悬停效果 */
.city-item {
    transition: all 0.3s ease;
    cursor: default;
}

.city-item:hover {
    transform: translateX(5px);
    color: var(--color-orange);
}

.city-item:hover .city-dot {
    transform: scale(1.3);
    box-shadow: 0 0 10px var(--color-orange);
}

.city-dot {
    transition: all 0.3s ease;
}

/* 页脚链接悬停 */
.footer-link {
    position: relative;
    transition: all 0.3s ease;
}

.footer-link:hover {
    transform: translateY(-2px);
}

.footer-link svg {
    transition: transform 0.3s ease;
}

.footer-link:hover svg {
    transform: scale(1.2);
}

/* CTA标题动画 */
.cta-title {
    animation: fadeInUp 0.8s ease forwards;
    opacity: 0;
}

.cta .btn {
    animation: fadeInUp 0.8s ease forwards;
    animation-delay: 0.3s;
    opacity: 0;
}

.services-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 3rem;
    max-width: 90rem;
    margin: 0 auto;
}

.service-card:hover .service-icon,
.service-card:hover .service-name,
.service-card:hover .service-desc {
    transform: scale(1.1);
}

.service-icon {
    width: 3.5rem;
    height: 3.5rem;
    margin: 0 auto 1.5rem;
    color: var(--color-orange);
    transition: transform 0.3s ease;
}

.service-icon svg {
    width: 100%;
    height: 100%;
    stroke-dasharray: 300;
    stroke-dashoffset: 0;
}

.service-card:hover .service-icon svg {
    animation: drawSvg 1.5s ease-in-out forwards;
}

@keyframes drawSvg {
    0% {
        stroke-dashoffset: 300;
    }
    100% {
        stroke-dashoffset: 0;
    }
}

.service-name {
    font-family: var(--font-heading);
    font-size: 1.125rem;
    font-weight: 500;
    color: var(--color-text);
    margin-bottom: 0.75rem;
    transition: transform 0.3s ease;
}

.service-desc {
    width: 100%;
    margin: 0 auto;
    text-align: left;
    font-size: 0.8125rem;
    color: var(--color-text);
    line-height: 1.6;
    opacity: 0.8;
    transition: opacity 0.3s ease, transform 0.3s ease;
    word-break: break-word;
    overflow-wrap: break-word;
}

.service-card:hover .service-desc {
    opacity: 1;
}

.service-card-link {
    display: block;
    text-decoration: none;
    color: inherit;
    min-width: 0;
}

.service-btn {
    display: inline-block;
    margin-top: 1rem;
    padding: 0.5rem 1.5rem;
    font-size: 0.8125rem;
    font-family: var(--font-body);
    color: var(--color-orange);
    background: transparent;
    border: 1px solid var(--color-orange);
    border-radius: 2px;
    cursor: pointer;
    letter-spacing: 0.05em;
    opacity: 0;
    transform: translateY(10px);
    transition: all 0.3s ease;
}

.service-card:hover .service-btn {
    opacity: 1;
    transform: translateY(0);
}

.service-btn:hover {
    background: var(--color-orange);
    color: var(--color-bg);
}

/* ============================================
   About Section
   ============================================ */
.about {
    padding: 6rem 0;
    background-color: var(--color-bg-light);
}

.about-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.section-label {
    cursor: default;
    display: block;
    font-family: var(--font-heading);
    font-weight: 400;
    font-size: 1.2rem;
    color: var(--color-text);
    margin-bottom: 1rem;
}

.about-text {
    font-size: 0.9375rem;
    color: var(--color-text);
    line-height: 1.8;
    margin-bottom: 2rem;
}

.about-image {
    position: relative;
    overflow: hidden;
    border-radius: 2px;
    background: linear-gradient(135deg, #0f1629 0%, #1a2744 50%, #0a0e1a 100%);
}

.about-image img {
    width: 100%;
    height: 400px;
    object-fit: cover;
    transition: var(--transition);
}

.about-image img.img-error {
    display: none;
}

.about-image:hover img,
.network-map:hover img,
.features-image:hover img {
    transform: scale(1.05);
}

/* ============================================
   Network Section
   ============================================ */
.network {
    padding: 6rem 0;
    background-color: var(--color-bg);
}

.network-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.network-map {
    background: linear-gradient(135deg, #0f1629 0%, #1a2744 50%, #0a0e1a 100%);
    border-radius: 2px;
}

.network-map img {
    width: 100%;
    height: 350px;
    object-fit: cover;
    border-radius: 2px;
    transition: var(--transition);
}

.network-map img.img-error {
    display: none;
}

.network-content .section-title {
    text-align: left;
    margin-bottom: 1rem;
}

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

.city-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.9375rem;
    color: var(--color-text);
}

.city-dot {
    width: 8px;
    height: 8px;
    background-color: var(--color-orange);
    border-radius: 50%;
    flex-shrink: 0;
}

.network-desc {
    font-size: 0.875rem;
    color: var(--color-text);
    line-height: 1.7;
}

/* ============================================
   Features Section
   ============================================ */
.features {
    padding: 6rem 0;
    background-color: var(--color-bg-light);
}

.features-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}
.features-header {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.features-image {
    background: linear-gradient(135deg, #0f1629 0%, #1a2744 50%, #0a0e1a 100%);
    border-radius: 2px;
}

.features-image img {
    width: 100%;
    height: 400px;
    object-fit: cover;
    border-radius: 2px;
    transition: var(--transition);
}

.features-image img.img-error {
    display: none;
}

.features-icon {
    width: 3rem;
    height: 3rem;
    color: var(--color-orange);
    margin-bottom: 1.5rem;
}

.features-content {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.features-content .section-title {
    text-align: left;
    margin-bottom: 2rem;
    font-size: 1.875rem;
}

.features-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.features-list li {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 0.9375rem;
    color: var(--color-text);
}

.features-list li::before {
    content: '✓';
    display: flex;
    align-items: center;
    justify-content: center;
    width: 20px;
    height: 20px;
    background-color: var(--color-orange);
    color: var(--color-bg);
    font-size: 0.75rem;
    font-weight: 700;
    border-radius: 50%;
    flex-shrink: 0;
}

/* ============================================
   About / Network / Features - 全高图片 + 毛玻璃衔接
   ============================================ */
@media (min-width: 1024px) {
    section.about,
    section.network,
    section.features {
        padding: 0;
    }

    .about-container,
    .network-container,
    .features-container {
        /* gap: 0;
        align-items: stretch; */
        max-width: 100rem;
    }

    .about-content,
    .network-content,
    .features-content {
        padding: 6rem 0;
    }

    .about-image,
    .network-map,
    .features-image {
        position: relative;
        overflow: hidden;
        height: 100%;
        border-radius: 0;
    }

    .about-image img,
    .network-map img,
    .features-image img {
        height: 100%;
        width: 100%;
        object-fit: cover;
        border-radius: 0;
    }

    .about-content,
    .network-content,
    .features-content {
        position: relative;
        padding: 6rem 0;
        z-index: 1;
    }

    .about-content::after,
    .features-content::after {
        content: '';
        position: absolute;
        top: 0;
        right: -14rem;
        width: 10rem;
        height: 100%;
        background: linear-gradient(to right, var(--color-bg-light), transparent);
        pointer-events: none;
        z-index: 1;
    }

    .network-content::after {
        content: '';
        position: absolute;
        top: 0;
        left: -14rem;
        width: 10rem;
        height: 100%;
        background: linear-gradient(to right, transparent, var(--color-bg));
        pointer-events: none;
        z-index: 1;
    }
}

/* ============================================
   CTA Section
   ============================================ */
.cta {
    padding: 4rem 0;
    background-color: var(--color-bg);
    border-top: 1px solid var(--color-border);
    border-bottom: 1px solid var(--color-border);
}

.cta-container {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 3rem;
}

.cta-title {
    font-family: var(--font-heading);
    font-size: 2rem;
    font-weight: 400;
    letter-spacing: 0.2rem;
    color: var(--color-orange);
}

/* ============================================
   Footer
   ============================================ */
.footer {
    padding: 3rem 0;
    background-color: var(--color-bg);
    border-top: 1px solid var(--color-border);
}

.footer-container {
    display: flex;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    gap: 1.5rem;
}

.footer-contact {
    display: flex;
    align-items: center;
    gap: 2rem;
    flex-wrap: wrap;
    justify-content: center;
}

.footer-link {
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.875rem;
    color: var(--color-text);
    transition: var(--transition);
}

.footer-link svg {
    width: 16px;
    height: 16px;
    flex-shrink: 0;
}

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

.footer-address {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.8125rem;
    max-width: 100%;
}

.footer-address svg {
    width: 14px;
    height: 14px;
    flex-shrink: 0;
}

.footer-copy {
    font-size: 0.75rem;
    color: var(--color-text-muted);
}

/* ============================================
   Contact Page
   ============================================ */
.contact-hero {
    padding: 10rem 0 4rem;
    background-color: var(--color-bg-light);
    text-align: center;
}

.contact-title {
    font-family: var(--font-heading);
    font-size: 3rem;
    font-weight: 400;
    color: var(--color-orange);
    margin-bottom: 1rem;
}

.contact-subtitle {
    font-size: 1.5rem;
    color: var(--color-text);
}

.contact-section {
    padding: 4rem 0 6rem;
    background-color: var(--color-bg);
}

.contact-container {
    display: grid;
    grid-template-columns: 1fr 1.2fr;
    gap: 4rem;
}

.contact-info {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
    align-content: start;
}

.contact-card {
    background-color: var(--color-bg-card);
    border: 1px solid var(--color-border);
    padding: 2rem;
    text-align: center;
    transform-style: preserve-3d;
    transform: perspective(800px);
    will-change: transform;
}

.contact-card-address.contact-card {
    padding: 2rem 0 1rem 0;
}

.contact-card-address .contact-card-title {
    padding: 0 2rem;
}

.contact-card {
    position: relative;
    border-radius: 1rem;
}

.contact-card::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, rgba(255, 107, 0, 0.1) 0%, transparent 50%);
    opacity: 0;
    transition: opacity 0.3s ease;
    pointer-events: none;
    border-radius: inherit;
}

.contact-card:hover::before {
    opacity: 1;
}
.contact-card:hover {
    border-color: var(--color-orange);
}

.contact-card-icon {
    width: 2.5rem;
    height: 2.5rem;
    margin: 0 auto 1rem;
    color: var(--color-orange);
    transform: translateZ(50px);
}

.contact-card-icon svg {
    width: 100%;
    height: 100%;
}

.contact-card h3 {
    transform: translateZ(50px);
    font-family: var(--font-heading);
    font-size: 1rem;
    font-weight: 500;
    color: var(--color-orange);
    margin-bottom: 0.5rem;
}

.contact-link.contact-card-content  {
    transform: translateZ(50px);
}

.contact-link.contact-card-content a {
    color: var(--color-text);
}

.contact-card p,
.contact-link {
    font-size: 0.875rem;
    color: var(--color-text);
}

.contact-link:hover {
    color: var(--color-orange);
}

/* Contact Form */
.contact-form {
    border-radius: 1rem;
    background-color: var(--color-bg-card);
    border: 1px solid var(--color-border);
    padding: 2.5rem;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.form-full {
    grid-column: 1 / -1;
}

.form-group label {
    font-size: 0.8125rem;
    font-weight: 500;
    color: var(--color-text);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.form-group input,
.form-group select,
.form-group textarea {
    padding: 0.75rem 1rem;
    background-color: var(--color-bg);
    border: 1px solid var(--color-border);
    color: var(--color-text);
    font-family: var(--font-body);
    font-size: 0.875rem;
    border-radius: 2px;
    transition: var(--transition);
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--color-orange);
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: var(--color-text);
}

.form-group select {
    cursor: pointer;
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%2394a3b8' stroke-width='2'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 1rem center;
}

.form-group select option {
    background-color: var(--color-bg);
    color: var(--color-text);
}

.btn-submit {
    width: 100%;
    padding: 1rem;
    font-size: 0.875rem;
}
.gradient {
    /* 设置容器尺寸 - 原理1 */
    /* 背景渐变色 - 原理2 */
    background: linear-gradient(45deg, var(--color-orange-light), var(--color-orange), var(--color-orange-dark), var(--color-orange));
    /* 背景尺寸 - 原理3 */
    background-size: 200% 200%;
    /* 循环动画 - 原理4 */
    animation: gradientBG 3s ease infinite;
}

  
/* ============================================
   Animations
   ============================================ */
/* 动画，控制背景 background-position */
@keyframes gradientBG {
    0% {
        background-position: 0% 50%;
    }
    50% {
        background-position: 100% 50%;
    }
    100% {
        background-position: 0% 50%;
    }
}

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

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

@keyframes fadeInLeft {
    from {
        opacity: 0;
        transform: translateX(-30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

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

@keyframes scaleIn {
    from {
        opacity: 0;
        transform: scale(0.9);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

@keyframes fadeOutLeft {
    from {
        opacity: 1;
        transform: translateX(0);
    }
    to {
        opacity: 0;
        transform: translateX(-30px);
    }
}

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

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

.animate-fade-in-down {
    animation: fadeInDown 0.8s ease forwards;
}

.animate-fade-in-left {
    animation: fadeInLeft 0.8s ease forwards;
}

.animate-fade-in-right {
    animation: fadeInRight 0.8s ease forwards;
}

.animate-scale-in {
    animation: scaleIn 0.8s ease forwards;
}

.parallax-bg {
    position: relative;
}

.parallax-bg::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(180deg, 
        rgba(10, 14, 26, 0.3) 0%, 
        rgba(10, 14, 26, 0) 30%,
        rgba(10, 14, 26, 0) 70%,
        rgba(10, 14, 26, 0.5) 100%
    );
    pointer-events: none;
    z-index: 1;
}

.section-fade {
    position: relative;
    overflow: hidden;
}

.section-fade::before,
.section-fade::after {
    content: '';
    position: absolute;
    left: 0;
    right: 0;
    height: 100px;
    pointer-events: none;
    z-index: 2;
}

.section-fade::before {
    top: 0;
    background: linear-gradient(to bottom, var(--color-bg), transparent);
}

.section-fade::after {
    bottom: 0;
    background: linear-gradient(to top, var(--color-bg), transparent);
}

/* ============================================
   Responsive - Tablet (768px - 1023px)
   ============================================ */
@media (max-width: 1023px) and (min-width: 768px) {
    html {
        font-size: 15px;
    }

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

    .about-container,
    .network-container,
    .features-container {
        grid-template-columns: 1fr;
        gap: 3rem;
    }

    .about-image img,
    .features-image img {
        height: 300px;
    }

    .network-map {
        order: 2;
    }

    .network-content {
        order: 1;
    }

    .features-image {
        order: 2;
    }

    .features-content {
        order: 1;
    }

    .contact-container {
        grid-template-columns: 1fr;
    }

    .contact-info {
        grid-template-columns: repeat(4, 1fr);
    }

    .cta-container {
        flex-direction: column;
        gap: 1.5rem;
        text-align: center;
    }

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

/* ============================================
   Responsive - Mobile (< 768px)
   ============================================ */
@media (max-width: 767px) {
    html {
        font-size: 14px;
    }

    .container {
        padding: 0 2.4rem;
    }

    .header-container {
        height: 4rem;
    }

    .nav {
        position: fixed;
        top: 4rem;
        left: 0;
        right: 0;
        background: rgba(10, 14, 26, 0.98);
        backdrop-filter: blur(10px);
        border-bottom: 1px solid var(--color-border);
        padding: 1.5rem;
        transform: translateY(-150%);
        opacity: 0;
        transition: var(--transition);
        pointer-events: none;
    }

    .nav.active {
        transform: translateY(0);
        opacity: 1;
        pointer-events: all;
    }

    .nav-list {
        flex-direction: column;
        gap: 1.5rem;
        align-items: flex-start;
    }

    .mobile-toggle {
        display: flex;
    }

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

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

    .mobile-toggle.active span:nth-child(3) {
        transform: rotate(-45deg) translate(5px, -5px);
    }

    .hero-title {
        font-size: 2.5rem;
    }

    .hero-subtitle {
        font-size: 1rem;
    }

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

    .section-title {
        font-size: 1.75rem;
    }

    .about-container,
    .network-container,
    .features-container {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .about .section-title,
    .network-content .section-title,
    .features-content .section-title {
        text-align: center;
    }

    .about-image img,
    .features-image img {
        height: 250px;
    }

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

    .cta-container {
        flex-direction: column;
        gap: 1.5rem;
        text-align: center;
    }

    .cta-title {
        font-size: 1.5rem;
    }

    .footer-container {
        flex-direction: column;
        text-align: center;
        gap: 1rem;
    }

    .footer-contact {
        flex-direction: column;
        gap: 1rem;
    }

    /* Contact page mobile */
    .contact-hero {
        padding: 8rem 0 3rem;
    }

    .contact-title {
        font-size: 2rem;
    }

    .contact-container {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .contact-info {
        grid-template-columns: 1fr 1fr;
    }

    .contact-form {
        grid-template-columns: 1fr;
        padding: 1.5rem;
    }
}

/* ============================================
   Responsive - Small Mobile (< 480px)
   ============================================ */
@media (max-width: 479px) {
    html {
        font-size: 20px;
    }

    .hero-title {
        font-size: 2.4rem;
    }

    .network-cities {
        grid-template-columns: 1fr;
    }

    .contact-info {
        grid-template-columns: 1fr;
    }

    .service-card {
        padding: 2rem 1rem;
    }
}