/* ==================== 全局样式 ==================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --color-black: #000000;
    --color-white: #ffffff;
    --color-gray-50: #fafafa;
    --color-gray-100: #f5f5f5;
    --color-gray-200: #e5e5e5;
    --color-gray-300: #d4d4d4;
    --color-gray-400: #a3a3a3;
    --color-gray-500: #737373;
    --color-gray-600: #525252;
    --color-gray-700: #404040;
    --color-gray-800: #262626;
    --color-gray-900: #171717;
    
    --transition-fast: 0.2s ease;
    --transition-medium: 0.3s ease;
    --transition-slow: 0.5s ease;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 
                 'Microsoft YaHei', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    background-color: var(--color-white);
    color: var(--color-black);
    line-height: 1.6;
    overflow-x: hidden;
}

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

/* ==================== 页面加载动画 ==================== */
.page-loader {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: var(--color-black);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
    opacity: 1;
    transition: opacity 0.5s ease;
}

.page-loader.hidden {
    opacity: 0;
    pointer-events: none;
}

.loader-content {
    text-align: center;
}

.loader-text {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--color-white);
    margin-bottom: 30px;
    letter-spacing: 8px;
}

.loader-bar {
    width: 200px;
    height: 2px;
    background-color: var(--color-gray-800);
    margin: 0 auto;
    overflow: hidden;
}

.loader-progress {
    width: 0;
    height: 100%;
    background-color: var(--color-white);
    animation: loading 1.5s ease-in-out;
}

@keyframes loading {
    0% {
        width: 0;
    }
    100% {
        width: 100%;
    }
}

/* ==================== 导航栏 ==================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-gray-200);
    z-index: 1000;
    transition: all var(--transition-medium);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 10px;
}

.brand-logo {
    font-size: 1.25rem;
    font-weight: 700;
    letter-spacing: 2px;
}

.brand-divider {
    color: var(--color-gray-400);
    font-size: 1rem;
}

.brand-subtitle {
    font-size: 0.875rem;
    color: var(--color-gray-500);
    font-weight: 400;
}

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

.nav-link {
    color: var(--color-gray-600);
    text-decoration: none;
    font-size: 0.9375rem;
    font-weight: 500;
    transition: color var(--transition-fast);
    position: relative;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--color-black);
    transition: width var(--transition-fast);
}

.nav-link:hover {
    color: var(--color-black);
}

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

/* ==================== Hero 区域 ==================== */
.hero-section {
    padding-top: 150px;
    padding-bottom: 100px;
    background: linear-gradient(180deg, var(--color-gray-50) 0%, var(--color-white) 100%);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.hero-content {
    text-align: center;
    max-width: 800px;
    margin: 0 auto 80px;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 20px;
    letter-spacing: -1px;
    opacity: 0;
    transform: translateY(30px);
    animation: fadeInUp 0.8s ease forwards 0.5s;
}

.hero-subtitle {
    font-size: 1.5rem;
    color: var(--color-gray-500);
    margin-bottom: 20px;
    opacity: 0;
    transform: translateY(30px);
    animation: fadeInUp 0.8s ease forwards 0.7s;
}

.hero-description {
    font-size: 1.125rem;
    color: var(--color-gray-600);
    line-height: 1.8;
    margin-bottom: 40px;
    opacity: 0;
    transform: translateY(30px);
    animation: fadeInUp 0.8s ease forwards 0.9s;
}

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

.hero-buttons {
    display: flex;
    gap: 20px;
    justify-content: center;
    opacity: 0;
    transform: translateY(30px);
    animation: fadeInUp 0.8s ease forwards 1.1s;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 16px 32px;
    font-size: 1rem;
    font-weight: 500;
    text-decoration: none;
    border-radius: 8px;
    transition: all var(--transition-medium);
    cursor: pointer;
}

.btn-text,
.btn-icon {
    transition: transform var(--transition-fast);
}

.btn:hover .btn-icon {
    transform: translateX(4px);
}

.btn-primary {
    background-color: var(--color-black);
    color: var(--color-white);
    border: 2px solid var(--color-black);
}

.btn-primary:hover {
    background-color: var(--color-white);
    color: var(--color-black);
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

.btn-secondary {
    background-color: var(--color-white);
    color: var(--color-black);
    border: 2px solid var(--color-black);
}

.btn-secondary:hover {
    background-color: var(--color-black);
    color: var(--color-white);
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

/* ==================== Hero 特性卡片 ==================== */
.hero-features {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
    max-width: 1000px;
    margin: 0 auto;
}

.feature-card {
    background-color: var(--color-white);
    border: 1px solid var(--color-gray-200);
    border-radius: 12px;
    padding: 40px 30px;
    text-align: center;
    transition: all var(--transition-medium);
    cursor: pointer;
    opacity: 0;
    transform: translateY(30px);
}

.feature-card:nth-child(1) {
    animation: fadeInUp 0.8s ease forwards 1.3s;
}

.feature-card:nth-child(2) {
    animation: fadeInUp 0.8s ease forwards 1.5s;
}

.feature-card:nth-child(3) {
    animation: fadeInUp 0.8s ease forwards 1.7s;
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.08);
    border-color: var(--color-black);
}

.feature-icon {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    background-color: var(--color-gray-50);
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 20px;
    font-size: 1.5rem;
    font-weight: 700;
    transition: all var(--transition-medium);
}

.feature-card:hover .feature-icon {
    background-color: var(--color-black);
    color: var(--color-white);
}

.feature-card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 10px;
}

.feature-card p {
    font-size: 0.9375rem;
    color: var(--color-gray-500);
    line-height: 1.6;
}

/* ==================== 通用 Section 样式 ==================== */
section {
    padding: 100px 0;
}

.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 20px;
}

.section-divider {
    width: 60px;
    height: 3px;
    background-color: var(--color-black);
    margin: 0 auto 20px;
}

.section-subtitle {
    font-size: 1.125rem;
    color: var(--color-gray-500);
}

/* ==================== 联系我们 ==================== */
.contact-section {
    background-color: var(--color-gray-50);
}

.contact-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.contact-card {
    background-color: var(--color-white);
    border-radius: 12px;
    padding: 50px 40px;
    text-align: center;
    transition: all var(--transition-medium);
    border: 1px solid var(--color-gray-200);
}

.contact-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.08);
}

.contact-card-primary:hover {
    border-color: var(--color-black);
}

.contact-card-secondary:hover {
    border-color: var(--color-black);
}

.contact-card-tertiary:hover {
    border-color: var(--color-black);
}

.contact-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 25px;
    color: var(--color-black);
    transition: all var(--transition-medium);
}

.contact-card:hover .contact-icon {
    transform: scale(1.1);
}

.contact-card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 15px;
}

.contact-value {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 10px;
    color: var(--color-black);
}

.contact-note {
    font-size: 0.9375rem;
    color: var(--color-gray-500);
}

/* ==================== 常见问题 ==================== */
.faq-section {
    background-color: var(--color-white);
}

.faq-container {
    max-width: 900px;
    margin: 0 auto;
}

.faq-item {
    border-bottom: 1px solid var(--color-gray-200);
    margin-bottom: 20px;
}

.faq-question {
    width: 100%;
    padding: 25px 0;
    background: none;
    border: none;
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    text-align: left;
    font-size: 1.125rem;
    font-weight: 500;
    color: var(--color-black);
    transition: color var(--transition-fast);
}

.faq-question:hover {
    color: var(--color-gray-600);
}

.faq-q-text {
    flex: 1;
    padding-right: 20px;
}

.faq-icon {
    width: 30px;
    height: 30px;
    border-radius: 50%;
    background-color: var(--color-gray-100);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    font-weight: 300;
    transition: all var(--transition-medium);
    flex-shrink: 0;
}

.faq-item.active .faq-icon {
    background-color: var(--color-black);
    color: var(--color-white);
    transform: rotate(45deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease, padding 0.4s ease;
}

.faq-answer p {
    padding-bottom: 15px;
    color: var(--color-gray-600);
    line-height: 1.8;
}

.faq-answer ul {
    padding-bottom: 15px;
    padding-left: 25px;
}

.faq-answer li {
    color: var(--color-gray-600);
    line-height: 1.8;
    margin-bottom: 8px;
}

.faq-answer strong {
    color: var(--color-black);
    font-weight: 600;
}

.faq-item.active .faq-answer {
    max-height: 500px;
    padding-bottom: 25px;
}

/* ==================== 问题反馈 ==================== */
.feedback-section {
    background-color: var(--color-gray-50);
}

.feedback-content {
    background-color: var(--color-white);
    border-radius: 12px;
    padding: 60px;
    text-align: center;
    border: 1px solid var(--color-gray-200);
}

.feedback-text {
    margin-bottom: 40px;
}

.feedback-text p {
    font-size: 1.125rem;
    color: var(--color-gray-600);
    line-height: 1.8;
    margin-bottom: 15px;
}

.feedback-email p {
    font-size: 1rem;
    color: var(--color-gray-500);
    margin-bottom: 15px;
}

.email-link {
    display: inline-block;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-black);
    text-decoration: none;
    padding: 15px 30px;
    border: 2px solid var(--color-black);
    border-radius: 8px;
    transition: all var(--transition-medium);
}

.email-link:hover {
    background-color: var(--color-black);
    color: var(--color-white);
    transform: translateY(-3px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

/* ==================== 页脚 ==================== */
.footer {
    background-color: var(--color-black);
    color: var(--color-white);
    padding: 60px 0 30px;
}

.footer-content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 60px;
    margin-bottom: 40px;
}

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

.footer-logo {
    font-size: 1.5rem;
    font-weight: 700;
    letter-spacing: 2px;
}

.footer-tagline {
    font-size: 0.9375rem;
    color: var(--color-gray-400);
}

.footer-links {
    display: flex;
    gap: 80px;
}

.footer-link-group h4 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 20px;
}

.footer-link-group a {
    display: block;
    color: var(--color-gray-400);
    text-decoration: none;
    font-size: 0.9375rem;
    margin-bottom: 12px;
    transition: color var(--transition-fast);
}

.footer-link-group a:hover {
    color: var(--color-white);
}

.footer-bottom {
    padding-top: 30px;
    border-top: 1px solid var(--color-gray-800);
    text-align: center;
}

.footer-bottom p {
    font-size: 0.875rem;
    color: var(--color-gray-500);
}

/* ==================== 响应式设计 ==================== */
@media (max-width: 768px) {
    /* 导航栏 */
    .nav-container {
        padding: 0 15px;
        height: 60px;
    }
    
    .nav-brand {
        gap: 8px;
    }
    
    .brand-logo {
        font-size: 1.125rem;
    }
    
    .brand-subtitle {
        font-size: 0.8125rem;
    }
    
    .nav-links {
        display: none;
    }
    
    /* Hero 区域 */
    .hero-section {
        padding-top: 100px;
        padding-bottom: 60px;
    }
    
    .hero-title {
        font-size: 2.25rem;
    }
    
    .hero-subtitle {
        font-size: 1.25rem;
    }
    
    .hero-description {
        font-size: 1rem;
    }
    
    .hero-buttons {
        flex-direction: column;
        gap: 15px;
    }
    
    .btn {
        width: 100%;
        justify-content: center;
    }
    
    /* Hero 特性卡片 */
    .hero-features {
        grid-template-columns: 1fr;
        gap: 20px;
    }
    
    .feature-card {
        padding: 30px 25px;
    }
    
    /* Section */
    section {
        padding: 60px 0;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    /* 联系我们 */
    .contact-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }
    
    .contact-card {
        padding: 40px 30px;
    }
    
    /* FAQ */
    .faq-question {
        font-size: 1rem;
        padding: 20px 0;
    }
    
    /* 反馈 */
    .feedback-content {
        padding: 40px 25px;
    }
    
    .feedback-text p {
        font-size: 1rem;
    }
    
    .email-link {
        font-size: 1.125rem;
        padding: 12px 24px;
        width: 100%;
        text-align: center;
    }
    
    /* 页脚 */
    .footer-content {
        grid-template-columns: 1fr;
        gap: 40px;
    }
    
    .footer-links {
        gap: 40px;
        flex-wrap: wrap;
    }
    
    .footer-link-group {
        flex: 1;
        min-width: 120px;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    .hero-title {
        font-size: 1.875rem;
    }
    
    .hero-subtitle {
        font-size: 1.125rem;
    }
    
    .section-title {
        font-size: 1.75rem;
    }
    
    .contact-value {
        font-size: 1.25rem;
    }
}