/* ==================== 重置和基础 ==================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* 配色方案 - 简约黑白灰 + 主色调 */
    --color-primary: #000000;
    --color-secondary: #333333;
    --color-accent: #2c2c2c;
    --color-text: #1a1a1a;
    --color-text-light: #666666;
    --color-text-lighter: #999999;
    --color-border: #e0e0e0;
    --color-bg: #ffffff;
    --color-bg-secondary: #fafafa;
    --color-bg-tertiary: #f5f5f5;
    
    /* 间距系统 */
    --spacing-xs: 8px;
    --spacing-sm: 16px;
    --spacing-md: 24px;
    --spacing-lg: 48px;
    --spacing-xl: 72px;
    --spacing-2xl: 120px;
    
    /* 字体大小 */
    --font-xs: 0.75rem;
    --font-sm: 0.875rem;
    --font-base: 1rem;
    --font-lg: 1.125rem;
    --font-xl: 1.5rem;
    --font-2xl: 2rem;
    --font-3xl: 3rem;
    --font-4xl: 4rem;
    
    /* 过渡 */
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-fast: all 0.15s cubic-bezier(0.4, 0, 0.2, 1);
    
    /* 阴影 */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.08);
}

/* 黑暗模式 */
[data-theme="dark"] {
    --color-primary: #ffffff;
    --color-secondary: #e0e0e0;
    --color-accent: #cccccc;
    --color-text: #ffffff;
    --color-text-light: #b0b0b0;
    --color-text-lighter: #808080;
    --color-border: #333333;
    --color-bg: #0a0a0a;
    --color-bg-secondary: #1a1a1a;
    --color-bg-tertiary: #2a2a2a;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Helvetica Neue', Arial, 'Noto Sans', sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji';
    line-height: 1.7;
    color: var(--color-text);
    background: var(--color-bg);
    transition: background 0.3s ease, color 0.3s ease;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* ==================== 导航栏 ==================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--color-border);
    z-index: 1000;
    transition: var(--transition);
}

[data-theme="dark"] .navbar {
    background: rgba(10, 10, 10, 0.8);
}

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

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    text-decoration: none;
    color: var(--color-primary);
    font-weight: 600;
}

.logo-icon {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 2px solid var(--color-primary);
    border-radius: 50%;
    font-size: var(--font-lg);
    transition: var(--transition);
}

.logo:hover .logo-icon {
    transform: rotate(90deg);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: var(--spacing-lg);
}

.nav-menu a {
    color: var(--color-text);
    text-decoration: none;
    font-size: var(--font-sm);
    font-weight: 500;
    letter-spacing: 0.05em;
    position: relative;
    transition: var(--transition);
}

.nav-menu a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 1px;
    background: var(--color-primary);
    transition: var(--transition);
}

.nav-menu a:hover {
    color: var(--color-primary);
}

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

.theme-toggle {
    width: 40px;
    height: 40px;
    border: 1px solid var(--color-border);
    background: transparent;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-text);
    transition: var(--transition);
}

.theme-toggle:hover {
    border-color: var(--color-primary);
    transform: rotate(15deg);
}

.mobile-toggle {
    display: none;
    flex-direction: column;
    gap: 6px;
    background: transparent;
    border: none;
    cursor: pointer;
    padding: 8px;
}

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

/* ==================== 首屏 ==================== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    padding-top: 80px;
}

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

.hero-label {
    font-size: var(--font-sm);
    letter-spacing: 0.2em;
    color: var(--color-text-light);
    margin-bottom: var(--spacing-md);
    opacity: 0;
    animation: fadeInUp 0.8s ease-out 0.2s forwards;
}

.hero-title {
    font-size: var(--font-4xl);
    font-weight: 300;
    line-height: 1.2;
    margin-bottom: var(--spacing-lg);
    letter-spacing: 0.05em;
}

.hero-title span {
    display: block;
    opacity: 0;
    animation: fadeInUp 0.8s ease-out forwards;
}

.hero-title span:nth-child(1) {
    animation-delay: 0.4s;
}

.hero-title span:nth-child(2) {
    animation-delay: 0.6s;
}

.hero-description {
    font-size: var(--font-lg);
    color: var(--color-text-light);
    margin-bottom: var(--spacing-xl);
    line-height: 1.8;
    opacity: 0;
    animation: fadeInUp 0.8s ease-out 0.8s forwards;
}

.hero-actions {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    flex-wrap: wrap;
    opacity: 0;
    animation: fadeInUp 0.8s ease-out 1s forwards;
}

.scroll-hint {
    position: absolute;
    bottom: var(--spacing-lg);
    left: 50%;
    transform: translateX(-50%);
    text-align: center;
    opacity: 0;
    animation: fadeIn 0.8s ease-out 1.5s forwards;
}

.scroll-line {
    display: block;
    width: 1px;
    height: 60px;
    background: var(--color-border);
    margin: 0 auto var(--spacing-sm);
    position: relative;
}

.scroll-line::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 20px;
    background: var(--color-primary);
    animation: scrollLine 2s ease-in-out infinite;
}

@keyframes scrollLine {
    0%, 20% {
        height: 0;
        top: 0;
    }
    80%, 100% {
        height: 0;
        top: 100%;
    }
}

.scroll-hint p {
    font-size: var(--font-xs);
    letter-spacing: 0.1em;
    color: var(--color-text-lighter);
}

/* ==================== 按钮 ==================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 14px 32px;
    font-size: var(--font-sm);
    font-weight: 500;
    letter-spacing: 0.05em;
    text-decoration: none;
    border: 1px solid var(--color-primary);
    background: var(--color-primary);
    color: var(--color-bg);
    cursor: pointer;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: var(--color-bg);
    transition: var(--transition);
    z-index: 0;
}

.btn:hover::before {
    left: 0;
}

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

.btn > * {
    position: relative;
    z-index: 1;
}

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

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

.btn-outline:hover {
    color: var(--color-bg);
}

.btn-block {
    width: 100%;
}

/* ==================== 通用章节 ==================== */
.section {
    padding: var(--spacing-2xl) 0;
}

.section-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.section-label {
    display: inline-block;
    font-size: var(--font-xs);
    letter-spacing: 0.2em;
    color: var(--color-text-lighter);
    margin-bottom: var(--spacing-sm);
}

.section-title {
    font-size: var(--font-3xl);
    font-weight: 300;
    margin-bottom: var(--spacing-md);
    letter-spacing: 0.02em;
}

.section-subtitle {
    font-size: var(--font-base);
    color: var(--color-text-light);
    max-width: 600px;
    margin: 0 auto;
}

/* ==================== 关于我们 ==================== */
.about {
    background: var(--color-bg-secondary);
}

.about-intro {
    max-width: 800px;
    margin: 0 auto var(--spacing-xl);
}

.lead-text {
    font-size: var(--font-xl);
    line-height: 1.8;
    margin-bottom: var(--spacing-lg);
    color: var(--color-text);
}

.about-intro p {
    margin-bottom: var(--spacing-md);
    line-height: 1.9;
    color: var(--color-text-light);
}

blockquote {
    margin: var(--spacing-lg) 0;
    padding-left: var(--spacing-lg);
    border-left: 2px solid var(--color-primary);
    font-size: var(--font-lg);
    font-style: italic;
    color: var(--color-text);
}

.about-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-xl);
}

.about-card {
    padding: var(--spacing-xl) var(--spacing-lg);
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    transition: var(--transition);
}

.about-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.card-number {
    font-size: var(--font-xl);
    font-weight: 300;
    color: var(--color-text-lighter);
    margin-bottom: var(--spacing-md);
}

.about-card h3 {
    font-size: var(--font-xl);
    font-weight: 400;
    margin-bottom: var(--spacing-md);
}

.about-card p {
    color: var(--color-text-light);
    line-height: 1.8;
}

/* ==================== 核心理念 ==================== */
.philosophy-grid {
    display: grid;
    gap: var(--spacing-xl);
    max-width: 900px;
    margin: 0 auto;
}

.philosophy-item {
    display: grid;
    grid-template-columns: auto 1fr;
    gap: var(--spacing-lg);
    padding: var(--spacing-xl) 0;
    border-bottom: 1px solid var(--color-border);
}

.philosophy-item:last-child {
    border-bottom: none;
}

.philosophy-icon {
    width: 80px;
    height: 80px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--color-border);
    border-radius: 50%;
    font-size: var(--font-2xl);
    color: var(--color-primary);
}

.philosophy-content h3 {
    font-size: var(--font-xl);
    font-weight: 400;
    margin-bottom: var(--spacing-md);
}

.philosophy-content p {
    color: var(--color-text-light);
    line-height: 1.9;
}

/* ==================== 公司特色 ==================== */
.features {
    background: var(--color-bg-secondary);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: var(--spacing-lg);
}

.feature-card {
    padding: var(--spacing-xl) var(--spacing-lg);
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    text-align: center;
    transition: var(--transition);
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.feature-icon {
    width: 60px;
    height: 60px;
    margin: 0 auto var(--spacing-md);
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--color-border);
    border-radius: 50%;
    font-size: var(--font-xl);
    color: var(--color-primary);
}

.feature-card h3 {
    font-size: var(--font-lg);
    font-weight: 400;
    margin-bottom: var(--spacing-md);
}

.feature-card p {
    color: var(--color-text-light);
    line-height: 1.8;
    font-size: var(--font-sm);
}

/* ==================== 联系我们 ==================== */
.contact-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: var(--spacing-xl);
    margin-top: var(--spacing-xl);
}

.contact-info h3 {
    font-size: var(--font-xl);
    font-weight: 400;
    margin-bottom: var(--spacing-xs);
}

.company-name-en {
    font-size: var(--font-xs);
    letter-spacing: 0.1em;
    color: var(--color-text-lighter);
    margin-bottom: var(--spacing-xl);
}

.info-item {
    display: flex;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.info-item i {
    width: 24px;
    height: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-text-light);
}

.info-item div {
    display: flex;
    flex-direction: column;
}

.info-label {
    font-size: var(--font-xs);
    color: var(--color-text-lighter);
    margin-bottom: 4px;
}

.info-value {
    font-size: var(--font-base);
    color: var(--color-text);
}

.social-links {
    display: flex;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-xl);
}

.social-links a {
    width: 40px;
    height: 40px;
    border: 1px solid var(--color-border);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-text);
    text-decoration: none;
    transition: var(--transition);
}

.social-links a:hover {
    border-color: var(--color-primary);
    transform: translateY(-2px);
}

/* 表单 */
.contact-form {
    padding: var(--spacing-xl);
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
}

.form-group {
    margin-bottom: var(--spacing-lg);
}

.form-group label {
    display: block;
    font-size: var(--font-sm);
    margin-bottom: var(--spacing-xs);
    color: var(--color-text-light);
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 14px 16px;
    border: 1px solid var(--color-border);
    background: var(--color-bg);
    color: var(--color-text);
    font-size: var(--font-base);
    font-family: inherit;
    transition: var(--transition);
}

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

.form-group textarea {
    resize: vertical;
}

/* ==================== 页脚 ==================== */
.footer {
    background: var(--color-bg-tertiary);
    padding: var(--spacing-xl) 0 var(--spacing-lg);
    border-top: 1px solid var(--color-border);
}

.footer-content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

.footer-brand p {
    margin-top: var(--spacing-md);
    color: var(--color-text-light);
    font-size: var(--font-sm);
}

.footer-links {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-lg);
}

.footer-column h4 {
    font-size: var(--font-base);
    font-weight: 500;
    margin-bottom: var(--spacing-md);
}

.footer-column ul {
    list-style: none;
}

.footer-column ul li {
    margin-bottom: var(--spacing-sm);
    font-size: var(--font-sm);
    color: var(--color-text-light);
}

.footer-column a {
    color: var(--color-text-light);
    text-decoration: none;
    transition: var(--transition);
}

.footer-column a:hover {
    color: var(--color-primary);
}

.footer-bottom {
    text-align: center;
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--color-border);
    font-size: var(--font-sm);
    color: var(--color-text-lighter);
}

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

@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.8s ease, transform 0.8s ease;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ==================== 响应式 ==================== */
@media (max-width: 768px) {
    :root {
        --font-3xl: 2.5rem;
        --font-4xl: 2.8rem;
        --spacing-2xl: 80px;
    }

    .nav-menu {
        display: none;
    }

    .mobile-toggle {
        display: flex;
    }

    .hero-title {
        font-size: var(--font-3xl);
    }

    .philosophy-item {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .philosophy-icon {
        margin: 0 auto;
    }

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

    .contact-form {
        padding: var(--spacing-lg);
    }
}

@media (max-width: 480px) {
    :root {
        --font-3xl: 2rem;
        --font-4xl: 2.2rem;
    }

    .hero-actions {
        flex-direction: column;
        width: 100%;
    }

    .btn {
        width: 100%;
    }

    .about-grid,
    .features-grid {
        grid-template-columns: 1fr;
    }
}

/* ==================== 自定义滚动条 ==================== */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--color-bg-secondary);
}

::-webkit-scrollbar-thumb {
    background: var(--color-border);
    transition: var(--transition);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--color-text-lighter);
}

/* ==================== 选中文本 ==================== */
::selection {
    background: var(--color-primary);
    color: var(--color-bg);
}

::-moz-selection {
    background: var(--color-primary);
    color: var(--color-bg);
}