/* Apple风格CSS样式 - BC产品经理差异展示网页 */

/* 基础重置和字体设置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Apple风格颜色变量 */
    --primary-color: #1d1d1f;
    --secondary-color: #86868b;
    --accent-color: #007aff;
    --background-color: #f5f5f7;
    --white: #ffffff;
    --black: #000000;
    --gray-100: #f5f5f7;
    --gray-200: #e5e5e7;
    --gray-300: #d2d2d7;
    --gray-400: #a1a1a6;
    --gray-500: #86868b;
    --gray-600: #6e6e73;
    --gray-700: #424245;
    --gray-800: #1d1d1f;
    
    /* B端和C端主题色 */
    --b-side-color: #007aff;
    --c-side-color: #ff3b30;
    
    /* 字体 */
    --font-family: -apple-system, BlinkMacSystemFont, 'SF Pro Display', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    
    /* 间距 */
    --section-padding: 80px 0;
    --container-padding: 0 20px;
    --max-width: 1200px;
    
    /* 阴影 */
    --shadow-light: 0 4px 20px rgba(0, 0, 0, 0.08);
    --shadow-medium: 0 8px 30px rgba(0, 0, 0, 0.12);
    --shadow-heavy: 0 16px 40px rgba(0, 0, 0, 0.16);
    
    /* 圆角 */
    --border-radius: 12px;
    --border-radius-large: 20px;
}

body {
    font-family: var(--font-family);
    line-height: 1.6;
    color: var(--primary-color);
    background-color: var(--background-color);
    font-size: 17px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* 导航栏样式 */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background-color: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--gray-200);
    z-index: 1000;
    transition: all 0.3s ease;
}

.navbar.scrolled {
    background-color: rgba(255, 255, 255, 0.95);
    box-shadow: var(--shadow-light);
}

.nav-container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: var(--container-padding);
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 60px;
}

.nav-logo h1 {
    font-size: 20px;
    font-weight: 600;
    color: var(--primary-color);
}

.nav-menu {
    display: flex;
    gap: 30px;
    align-items: center;
}

.nav-link {
    text-decoration: none;
    color: var(--gray-600);
    font-size: 14px;
    font-weight: 400;
    transition: color 0.3s ease;
    position: relative;
}

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

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--accent-color);
    transition: width 0.3s ease;
}

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

/* 英雄区域样式 */
.hero {
    padding: 120px 0 80px;
    background: linear-gradient(135deg, var(--white) 0%, var(--gray-100) 100%);
    text-align: center;
}

.hero-container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: var(--container-padding);
}

.hero-title {
    font-size: 56px;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 20px;
    letter-spacing: -0.02em;
}

.hero-subtitle {
    font-size: 28px;
    font-weight: 400;
    color: var(--gray-600);
    margin-bottom: 30px;
    letter-spacing: -0.01em;
}

.hero-description {
    max-width: 600px;
    margin: 0 auto;
}

.hero-description p {
    font-size: 21px;
    color: var(--gray-500);
    line-height: 1.5;
}

/* 主要内容区域 */
.main-content {
    padding: 0;
}

.content-section {
    padding: var(--section-padding);
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.6s ease;
}

.content-section.animate-in {
    opacity: 1;
    transform: translateY(0);
}

.section-container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: var(--container-padding);
}

.section-title {
    font-size: 48px;
    font-weight: 700;
    color: var(--primary-color);
    text-align: center;
    margin-bottom: 60px;
    letter-spacing: -0.02em;
}

/* 概览区域样式 */
.overview-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
    margin-top: 40px;
}

.overview-card {
    background: var(--white);
    padding: 40px;
    border-radius: var(--border-radius-large);
    box-shadow: var(--shadow-light);
    text-align: center;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.overview-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-medium);
}

.overview-card h3 {
    font-size: 24px;
    font-weight: 600;
    margin-bottom: 20px;
    color: var(--primary-color);
}

.overview-card p {
    font-size: 18px;
    color: var(--gray-600);
    line-height: 1.6;
}

/* 对比容器样式 */
.comparison-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
    margin-top: 40px;
}

.comparison-card {
    background: var(--white);
    padding: 40px;
    border-radius: var(--border-radius-large);
    box-shadow: var(--shadow-light);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    position: relative;
    overflow: hidden;
}

.comparison-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-medium);
}

.comparison-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--b-side-color), var(--c-side-color));
}

.comparison-card.b-side::before {
    background: var(--b-side-color);
}

.comparison-card.c-side::before {
    background: var(--c-side-color);
}

.comparison-card h3 {
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 20px;
    color: var(--primary-color);
}

.comparison-card.b-side h3 {
    color: var(--b-side-color);
}

.comparison-card.c-side h3 {
    color: var(--c-side-color);
}

.card-description {
    font-size: 18px;
    color: var(--gray-600);
    margin-bottom: 30px;
    line-height: 1.6;
}

/* 特性列表样式 */
.feature-list {
    list-style: none;
    margin-bottom: 30px;
}

.feature-list li {
    position: relative;
    padding-left: 30px;
    margin-bottom: 15px;
    font-size: 16px;
    color: var(--gray-700);
    line-height: 1.6;
}

.feature-list li::before {
    content: '•';
    position: absolute;
    left: 0;
    color: var(--accent-color);
    font-size: 20px;
    font-weight: bold;
}

.comparison-card.b-side .feature-list li::before {
    color: var(--b-side-color);
}

.comparison-card.c-side .feature-list li::before {
    color: var(--c-side-color);
}

/* 案例样式 */
.example {
    background: var(--gray-100);
    padding: 25px;
    border-radius: var(--border-radius);
    margin-bottom: 20px;
    border-left: 4px solid var(--accent-color);
}

.comparison-card.b-side .example {
    border-left-color: var(--b-side-color);
}

.comparison-card.c-side .example {
    border-left-color: var(--c-side-color);
}

.example h4 {
    font-size: 18px;
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: 15px;
}

.example p {
    font-size: 15px;
    color: var(--gray-600);
    line-height: 1.6;
}

/* 页脚样式 */
.footer {
    background: var(--primary-color);
    color: var(--white);
    padding: 40px 0;
    text-align: center;
}

.footer-container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: var(--container-padding);
}

.footer p {
    font-size: 14px;
    color: var(--gray-400);
}

/* 响应式设计 */
@media (max-width: 1024px) {
    .nav-menu {
        gap: 20px;
    }
    
    .nav-link {
        font-size: 13px;
    }
    
    .hero-title {
        font-size: 48px;
    }
    
    .hero-subtitle {
        font-size: 24px;
    }
    
    .section-title {
        font-size: 40px;
    }
    
    .comparison-container {
        gap: 30px;
    }
    
    .comparison-card {
        padding: 30px;
    }
}

@media (max-width: 768px) {
    :root {
        --section-padding: 60px 0;
        --container-padding: 0 16px;
    }
    
    .nav-container {
        flex-direction: column;
        height: auto;
        padding: 15px 16px;
    }
    
    .nav-menu {
        margin-top: 15px;
        flex-wrap: wrap;
        justify-content: center;
        gap: 15px;
    }
    
    .hero {
        padding: 100px 0 60px;
    }
    
    .hero-title {
        font-size: 36px;
    }
    
    .hero-subtitle {
        font-size: 20px;
    }
    
    .hero-description p {
        font-size: 18px;
    }
    
    .section-title {
        font-size: 32px;
        margin-bottom: 40px;
    }
    
    .overview-grid {
        grid-template-columns: 1fr;
        gap: 30px;
    }
    
    .comparison-container {
        grid-template-columns: 1fr;
        gap: 30px;
    }
    
    .comparison-card {
        padding: 25px;
    }
    
    .comparison-card h3 {
        font-size: 24px;
    }
    
    .card-description {
        font-size: 16px;
    }
    
    .example {
        padding: 20px;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 28px;
    }
    
    .hero-subtitle {
        font-size: 18px;
    }
    
    .section-title {
        font-size: 28px;
    }
    
    .comparison-card {
        padding: 20px;
    }
    
    .comparison-card h3 {
        font-size: 20px;
    }
    
    .example {
        padding: 15px;
    }
    
    .example h4 {
        font-size: 16px;
    }
    
    .example p {
        font-size: 14px;
    }
}

/* 滚动条样式 */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--gray-100);
}

::-webkit-scrollbar-thumb {
    background: var(--gray-400);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--gray-500);
}

/* 选择文本样式 */
::selection {
    background-color: var(--accent-color);
    color: var(--white);
}

/* 焦点样式 */
.nav-link:focus,
button:focus {
    outline: 2px solid var(--accent-color);
    outline-offset: 2px;
}

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

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

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

/* 打印样式 */
@media print {
    .navbar,
    .footer {
        display: none;
    }
    
    .hero {
        padding: 20px 0;
    }
    
    .content-section {
        padding: 20px 0;
        page-break-inside: avoid;
    }
    
    .comparison-container {
        grid-template-columns: 1fr;
    }
}