/* =============================================
   变量与基础设置
   ============================================= */
:root {
    /* 颜色系统 */
    --primary: #007AFF;
    --primary-dark: #0062cc;
    --background: #f9f9f9;
    --text: #333;
    --text-light: #555;
    --card: #ffffff;
    --border: rgba(230, 230, 230, 0.8);
    
    /* 交互元素 */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 12px rgba(31, 38, 135, 0.1);
    --shadow-lg: 0 10px 25px rgba(31, 38, 135, 0.15);
    --shadow-hover: 0 14px 30px rgba(31, 38, 135, 0.2);
    
    /* 间距 */
    --space-xs: 0.5rem;
    --space-sm: 1rem;
    --space-md: 1.5rem;
    --space-lg: 2.5rem;
    --space-xl: 4rem;
    
    /* 圆角 */
    --radius-sm: 6px;
    --radius-md: 12px;
    --radius-lg: 20px;
    
    /* 过渡 */
    --transition-fast: 0.2s ease;
    --transition: 0.3s ease;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background-color: var(--background);
    color: var(--text);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.container {
    width: 100%;
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 var(--space-md);
}

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

a:hover {
    color: var(--primary-dark);
}

/* 辅助类 */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

/* =============================================
   导航栏组件
   ============================================= */
.navbar {
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    padding: var(--space-sm) 0;
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 1000;
}

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

.logo { 
    font-size: 1.5rem; 
    font-weight: 600;
    color: var(--text);
}

.nav-links { 
    list-style: none; 
    display: flex;
    gap: var(--space-md);
}

.nav-links a { 
    font-weight: 500;
    color: var(--text);
    position: relative;
}

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

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

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

/* 语言选择器样式 */
.lang-container {
    display: flex;
    align-items: center;
    margin-left: var(--space-md);
}

.lang-icon {
    width: 18px;
    height: 18px;
    margin-right: 5px;
}

.lang-switcher { 
    border: 1px solid var(--border);
    padding: 6px 10px;
    border-radius: var(--radius-sm);
    background-color: transparent;
    font-family: inherit;
    cursor: pointer;
    transition: border-color var(--transition-fast);
}

.lang-switcher:hover {
    border-color: var(--primary);
}

/* =============================================
   主页英雄区域
   ============================================= */
.hero {
    display: flex;
    align-items: center;
    padding: var(--space-xl) 0;
    min-height: 85vh;
    overflow: hidden; 
}

.hero .container {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-xl);
    width: 100%;
}

.hero-content {
    flex-shrink: 0;
    max-width: 450px;
    text-align: left;
    position: relative;
    z-index: 2;
    padding: var(--space-xl);
}

.hero-content::before {
    content: '';
    position: absolute;
    inset: 0;
    background: rgba(255, 255, 255, 0.7);
    backdrop-filter: blur(15px);
    -webkit-backdrop-filter: blur(15px);
    z-index: -1;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    border: 1px solid rgba(255, 255, 255, 0.18);
    transition: box-shadow var(--transition);
}

.hero-content:hover::before {
    box-shadow: var(--shadow-hover);
}

.app-icon {
    width: 90px;
    height: 90px;
    border-radius: 22.5%;
    box-shadow: var(--shadow-md);
    margin-bottom: var(--space-md);
}

.app-name { 
    font-size: 2.8rem; 
    margin: var(--space-xs) 0;
    letter-spacing: -0.5px;
}

.app-description { 
    font-size: 1.1rem; 
    margin: 0 auto var(--space-lg); 
    color: var(--text-light);
}

.app-store-badge { 
    display: inline-block; 
    height: 50px;
}

/* 右侧图片区域布局 */
.hero-images {
    flex-shrink: 0;
    display: flex;
    align-items: center;
    z-index: 1;
}

.mockup {
    max-width: 100%;
    transition: transform var(--transition);
}

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

.iphone-mockup {
    max-width: 260px;
    position: relative;
    z-index: 1;
    box-shadow: 0 8px 18px rgba(0, 0, 0, 0.2);
    border-radius: 45px;
    overflow: hidden;
}

.carplay-mockup {
    max-width: 400px;
    border-radius: 10px;
    position: relative;
    z-index: 2;
    margin-left: -140px;
    box-shadow: 0 15px 28px rgba(0, 0, 0, 0.28);
}

/* =============================================
   FAQ页面样式
   ============================================= */
.faq-section {
    padding: var(--space-xl) var(--space-md);
    max-width: 800px;
    margin: auto;
}

.faq-section h1 {
    text-align: center;
    margin-bottom: var(--space-xl);
    color: var(--text);
}

.faq-item {
    background: var(--card);
    margin-bottom: var(--space-sm);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    overflow: hidden;
    transition: box-shadow var(--transition);
}

.faq-item:hover {
    box-shadow: var(--shadow-md);
}

.faq-question {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--space-md);
    cursor: pointer;
    font-weight: 500;
    font-size: 1.1rem;
}

.faq-question .icon {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary);
    transition: transform var(--transition);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition);
    padding: 0 var(--space-md);
}

.faq-answer p {
    padding-bottom: var(--space-md);
    margin: 0;
    color: var(--text-light);
    line-height: 1.7;
}

.faq-item.active .faq-question {
    border-bottom: 1px solid var(--border);
}

.faq-item.active .faq-question .icon {
    transform: rotate(180deg);
}

/* =============================================
   关于页面样式
   ============================================= */
.about-section {
    padding: var(--space-xl) var(--space-md);
    max-width: 800px;
    margin: auto;
    text-align: center;
}

.about-section h1 {
    margin-bottom: var(--space-md);
    color: var(--text);
}

.about-section p {
    font-size: 1.1rem;
    line-height: 1.8;
    color: var(--text-light);
    margin-bottom: var(--space-md);
}

.about-team {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-lg);
    justify-content: center;
    margin-top: var(--space-xl);
}

.team-member {
    background: var(--card);
    padding: var(--space-lg);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    transition: transform var(--transition), box-shadow var(--transition);
    width: 250px;
}

.team-member:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
}

/* =============================================
   动画效果
   ============================================= */
.reveal { 
    opacity: 0; 
    transform: translateY(30px); 
    transition: opacity 0.8s ease-out, transform 0.8s ease-out; 
}

.reveal.visible { 
    opacity: 1; 
    transform: translateY(0); 
}

/* =============================================
   页脚样式
   ============================================= */
.footer { 
    margin-top: auto;
    text-align: center; 
    padding: var(--space-lg) var(--space-md);
    background-color: #333; 
    color: #f9f9f9; 
}

/* 页脚导航样式 */
.footer-nav {
    margin-top: var(--space-md);
}

.footer-links {
    list-style: none;
    display: flex;
    justify-content: center;
    gap: var(--space-lg);
}

.footer-links a {
    color: #f9f9f9;
    text-decoration: underline;
    transition: opacity var(--transition-fast);
}

.footer-links a:hover, 
.footer-links a:focus {
    opacity: 0.8;
}

/* =============================================
   响应式布局
   ============================================= */
@media (max-width: 992px) {
    .hero .container { 
        gap: var(--space-md); 
    }
    
    .hero-content { 
        max-width: 400px;
        padding: var(--space-lg);
    }
    
    .iphone-mockup { 
        max-width: 240px; 
        border-radius: 26px; 
    }
    
    .carplay-mockup { 
        max-width: 360px; 
        margin-left: -120px; 
    }
}

@media (max-width: 768px) {
    .hero .container { 
        flex-direction: column; 
        gap: var(--space-xl); 
    }
    
    .hero-content { 
        text-align: center; 
        max-width: 100%; 
    }
    
    .hero-images { 
        flex-direction: row; 
    }
    
    .iphone-mockup { 
        max-width: 180px; 
        border-radius: 20px; 
    }
    
    .carplay-mockup { 
        max-width: 280px; 
        margin-left: -100px; 
    }
    
    .footer-links {
        flex-direction: column;
        align-items: center;
        gap: var(--space-xs);
    }
    
    .nav-links {
        gap: var(--space-sm);
    }
    
    .app-name {
        font-size: 2.2rem;
    }
}

@media (max-width: 576px) {
    :root {
        --space-lg: 1.5rem;
        --space-xl: 2.5rem;
    }
    
    .navbar .container {
        flex-wrap: wrap;
    }
    
    .lang-container {
        margin-top: var(--space-sm);
        margin-left: auto;
    }
    
    .hero {
        padding: var(--space-lg) 0;
    }
    
    .hero-content {
        padding: var(--space-md);
    }
    
    .hero-images {
        flex-direction: column;
        align-items: center;
    }
    
    .iphone-mockup {
        margin-bottom: var(--space-md);
    }
    
    .carplay-mockup {
        margin-left: 0;
        max-width: 300px;
    }
}