/* ============================================
   变量定义 - 苹果风格设计系统
   ============================================ */
:root {
    /* 颜色系统 */
    --color-bg-primary: #ffffff;
    --color-bg-secondary: #f5f5f7;
    --color-text-primary: #1d1d1f;
    --color-text-secondary: #86868b;
    --color-text-tertiary: #6e6e73;
    --color-accent: #0071e3;
    --color-accent-hover: #0077ed;
    --color-border: rgba(0, 0, 0, 0.1);
    
    /* 字体系统 */
    --font-family: -apple-system, BlinkMacSystemFont, 'Inter', 'Segoe UI', 'Helvetica Neue', Arial, sans-serif;
    --font-weight-light: 300;
    --font-weight-regular: 400;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;
    
    /* 间距系统 */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;
    --spacing-xxl: 8rem;
    
    /* 圆角系统 */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 18px;
    --radius-xl: 24px;
    
    /* 阴影系统 */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.12);
    
    /* 过渡动画 */
    --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-normal: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ============================================
   基础样式重置
   ============================================ */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-family);
    font-weight: var(--font-weight-regular);
    background-color: var(--color-bg-primary);
    color: var(--color-text-primary);
    line-height: 1.6;
    overflow-x: hidden;
}

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

/* ============================================
   导航栏
   ============================================ */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background-color: rgba(255, 255, 255, 0.8);
    backdrop-filter: saturate(180%) blur(20px);
    -webkit-backdrop-filter: saturate(180%) blur(20px);
    border-bottom: 1px solid var(--color-border);
    transition: background-color var(--transition-normal);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo-wrapper {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    transition: opacity var(--transition-fast);
}

.nav-logo-wrapper:hover {
    opacity: 0.8;
}

.logo-icon {
    width: 32px;
    height: 20px;
    color: var(--color-text-primary);
    transition: transform var(--transition-normal);
}

.nav-logo-wrapper:hover .logo-icon {
    transform: scale(1.05);
}

.nav-logo-text {
    font-size: 1.25rem;
    font-weight: var(--font-weight-semibold);
    color: var(--color-text-primary);
    letter-spacing: -0.02em;
}

.nav-links {
    display: flex;
    gap: 2.5rem;
}

.nav-links a {
    font-size: 0.875rem;
    font-weight: var(--font-weight-regular);
    color: var(--color-text-secondary);
    transition: color var(--transition-fast);
}

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

/* ============================================
   Hero 区域
   ============================================ */
.hero {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    padding: 8rem 2rem 4rem;
    position: relative;
    background: linear-gradient(to bottom, var(--color-bg-primary), var(--color-bg-secondary));
}

.hero-content {
    max-width: 800px;
    animation: fadeInUp 0.8s ease-out;
}

.hero-logo-wrapper {
    margin-bottom: 2rem;
    display: flex;
    justify-content: center;
    animation: fadeInUp 0.8s ease-out 0.2s both;
}

.hero-logo {
    width: 100%;
    max-width: 300px;
    height: auto;
    color: var(--color-text-primary);
    opacity: 0.9;
    transition: transform var(--transition-slow), opacity var(--transition-normal);
}

.hero-logo-wrapper:hover .hero-logo {
    transform: scale(1.05);
    opacity: 1;
}

/* 两只鲸鱼动画 */
.hero-logo .whale-1 {
    animation: swim 3s ease-in-out infinite;
    transform-origin: center;
}

.hero-logo .whale-2 {
    animation: swim 3s ease-in-out infinite 0.5s;
    transform-origin: center;
}

@keyframes swim {
    0%, 100% {
        transform: translateY(0) translateX(0);
    }
    25% {
        transform: translateY(-3px) translateX(2px);
    }
    50% {
        transform: translateY(0) translateX(0);
    }
    75% {
        transform: translateY(3px) translateX(-2px);
    }
}

.hero-title {
    font-size: clamp(3rem, 8vw, 6rem);
    font-weight: var(--font-weight-bold);
    letter-spacing: -0.04em;
    line-height: 1.1;
    margin-bottom: 1.5rem;
    color: var(--color-text-primary);
}

.hero-subtitle {
    font-size: clamp(1.5rem, 4vw, 2.5rem);
    font-weight: var(--font-weight-light);
    color: var(--color-text-primary);
    margin-bottom: 0.5rem;
    letter-spacing: -0.02em;
}

.hero-description {
    font-size: clamp(1rem, 2vw, 1.25rem);
    color: var(--color-text-secondary);
    font-weight: var(--font-weight-regular);
    margin-top: 1rem;
}

.hero-scroll-indicator {
    position: absolute;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%);
    animation: bounce 2s infinite;
}

.scroll-arrow {
    width: 24px;
    height: 24px;
    border-right: 2px solid var(--color-text-secondary);
    border-bottom: 2px solid var(--color-text-secondary);
    transform: rotate(45deg);
}

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

@keyframes bounce {
    0%, 100% {
        transform: translateX(-50%) translateY(0);
    }
    50% {
        transform: translateX(-50%) translateY(10px);
    }
}

/* ============================================
   通用区块样式
   ============================================ */
.section {
    padding: var(--spacing-xxl) 0;
    position: relative;
}

.section-alt {
    background-color: var(--color-bg-secondary);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

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

.section-title {
    font-size: clamp(2rem, 5vw, 3.5rem);
    font-weight: var(--font-weight-bold);
    letter-spacing: -0.03em;
    color: var(--color-text-primary);
    margin-bottom: 0.5rem;
}

/* ============================================
   介绍内容区域
   ============================================ */
.intro-content {
    max-width: 800px;
    margin: 0 auto;
}

.intro-text {
    font-size: clamp(1rem, 2vw, 1.25rem);
    line-height: 1.8;
    color: var(--color-text-secondary);
    font-weight: var(--font-weight-regular);
}

.highlight {
    color: var(--color-text-primary);
    font-weight: var(--font-weight-semibold);
}

/* ============================================
   功能卡片网格
   ============================================ */
.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2rem;
    margin-top: var(--spacing-lg);
}

.feature-card {
    background-color: var(--color-bg-primary);
    border-radius: var(--radius-lg);
    padding: 2.5rem;
    transition: transform var(--transition-normal), box-shadow var(--transition-normal);
    border: 1px solid var(--color-border);
    display: flex;
    flex-direction: column;
    position: relative;
    overflow: hidden;
}

.feature-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--color-accent), transparent);
    opacity: 0;
    transition: opacity var(--transition-normal);
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg);
}

.feature-card:hover::before {
    opacity: 1;
}

.feature-card-disabled {
    opacity: 0.6;
    cursor: default;
}

.feature-card-disabled:hover {
    transform: none;
    box-shadow: none;
}

.feature-icon {
    font-size: 3rem;
    
    display: block;
}

.feature-icon-image {
    width: 10rem;
    height: 10rem;
    object-fit: contain;
    display: block;
}

.feature-title {
    font-size: 1.5rem;
    font-weight: var(--font-weight-semibold);
    color: var(--color-text-primary);
    margin-bottom: 1rem;
    letter-spacing: -0.02em;
}

.feature-description {
    font-size: 1rem;
    line-height: 1.7;
    color: var(--color-text-secondary);
    margin-bottom: 2rem;
    flex-grow: 1;
    font-weight: var(--font-weight-regular);
}

.feature-link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1rem;
    font-weight: var(--font-weight-medium);
    color: var(--color-accent);
    transition: color var(--transition-fast), gap var(--transition-fast);
    margin-top: auto;
}

.feature-link:hover {
    color: var(--color-accent-hover);
    gap: 0.75rem;
}

.feature-link.disabled {
    color: var(--color-text-tertiary);
    cursor: default;
}

.feature-link.disabled:hover {
    gap: 0.5rem;
}

.link-arrow {
    font-size: 1.2rem;
    transition: transform var(--transition-fast);
}

.feature-link:hover .link-arrow {
    transform: translateX(4px);
}

.feature-link.disabled .link-arrow {
    display: none;
}

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

.footer .container {
    text-align: center;
}

.footer-text {
    font-size: 0.875rem;
    color: var(--color-text-tertiary);
    margin-bottom: 0.5rem;
    font-weight: var(--font-weight-regular);
}

.footer-link {
    color: var(--color-text-secondary);
    transition: color var(--transition-fast);
}

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

/* ============================================
   响应式设计
   ============================================ */
@media (max-width: 768px) {
    .nav-container {
        padding: 1rem 1.5rem;
    }
    
    .logo-icon {
        width: 28px;
        height: 18px;
    }
    
    .nav-logo-text {
        font-size: 1.1rem;
    }
    
    .nav-links {
        gap: 1.5rem;
    }
    
    .nav-links a {
        font-size: 0.8125rem;
    }
    
    .hero {
        padding: 6rem 1.5rem 3rem;
    }
    
    .hero-logo {
        max-width: 250px;
    }
    
    .section {
        padding: var(--spacing-lg) 0;
    }
    
    .container {
        padding: 0 1.5rem;
    }
    
    .feature-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .feature-card {
        padding: 2rem;
    }
    
    .section-header {
        margin-bottom: var(--spacing-md);
    }
}

@media (max-width: 480px) {
    .nav-logo-wrapper {
        gap: 0.5rem;
    }
    
    .logo-icon {
        width: 24px;
        height: 16px;
    }
    
    .nav-logo-text {
        font-size: 1rem;
    }
    
    .nav-links {
        gap: 1rem;
        font-size: 0.75rem;
    }
    
    .hero {
        padding: 5rem 1rem 2rem;
    }
    
    .hero-logo {
        max-width: 200px;
    }
    
    .feature-card {
        padding: 1.5rem;
    }
}

/* ============================================
   滚动动画增强
   ============================================ */
@media (prefers-reduced-motion: no-preference) {
    .feature-card {
        opacity: 0;
        transform: translateY(30px);
        animation: fadeInUp 0.6s ease-out forwards;
    }
    
    .feature-card:nth-child(1) {
        animation-delay: 0.1s;
    }
    
    .feature-card:nth-child(2) {
        animation-delay: 0.2s;
    }
    
    .feature-card:nth-child(3) {
        animation-delay: 0.3s;
    }
}

/* ============================================
   深色模式支持（可选）
   ============================================ */
@media (prefers-color-scheme: dark) {
    :root {
        --color-bg-primary: #000000;
        --color-bg-secondary: #1d1d1f;
        --color-text-primary: #f5f5f7;
        --color-text-secondary: #a1a1a6;
        --color-text-tertiary: #6e6e73;
        --color-border: rgba(255, 255, 255, 0.1);
    }
    
    .navbar {
        background-color: rgba(0, 0, 0, 0.8);
    }
}