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

:root {
    --primary-color: #4A90E2;
    --secondary-color: #50C878;
    --danger-color: #FF6B6B;
    --text-primary: #333333;
    --text-secondary: #666666;
    --text-light: #999999;
    --bg-light: #F5F7FA;
    --bg-white: #FFFFFF;
    --border-color: #E5E5E5;
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.12);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.15);
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-secondary: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    color: var(--text-primary);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* 语言切换按钮 */
.language-switch {
    position: absolute;
    top: 20px;
    right: 20px;
    z-index: 1000;
    display: flex;
    gap: 8px;
    background: rgba(255, 255, 255, 0.95);
    padding: 6px;
    border-radius: 20px;
    box-shadow: var(--shadow-md);
    -webkit-backdrop-filter: blur(10px);
    backdrop-filter: blur(10px);
}

.lang-btn {
    padding: 8px 16px;
    border: none;
    background: transparent;
    color: var(--text-secondary);
    font-size: 14px;
    font-weight: 500;
    border-radius: 16px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.lang-btn:hover {
    background: rgba(74, 144, 226, 0.1);
    color: var(--primary-color);
}

.lang-btn.active {
    background: var(--primary-color);
    color: white;
}

/* 主容器 */
.container {
    position: relative;
    max-width: 1200px;
    margin: 0 auto;
    padding: 60px 20px 40px;
}

/* 头部区域 */
.header {
    text-align: center;
    margin-bottom: 60px;
    animation: fadeInDown 0.8s ease;
}

.logo-section {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 16px;
    margin-bottom: 16px;
}

.logo-placeholder {
    font-size: 48px;
    animation: bounce 2s infinite;
}

.app-name {
    font-size: 36px;
    font-weight: 700;
    color: white;
    text-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
}

.tagline {
    font-size: 18px;
    color: rgba(255, 255, 255, 0.9);
    font-weight: 300;
}

/* APP信息区域 */
.app-info {
    text-align: center;
    margin-bottom: 40px;
    animation: fadeInUp 0.8s ease 0.2s both;
}

.app-icon-wrapper {
    margin-bottom: 24px;
}

.app-icon {
    width: 120px;
    height: 120px;
    margin: 0 auto;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 8px 32px rgba(102, 126, 234, 0.4);
    border: 4px solid rgba(255, 255, 255, 0.3);
}

.icon-text {
    font-size: 32px;
    font-weight: 700;
    color: white;
}

.app-title {
    font-size: 28px;
    font-weight: 600;
    color: white;
    margin-bottom: 8px;
}

.version {
    font-size: 14px;
    color: rgba(255, 255, 255, 0.8);
}

/* 下载按钮区域 */
.download-section {
    background: white;
    border-radius: 24px;
    padding: 40px;
    margin-bottom: 40px;
    box-shadow: var(--shadow-lg);
    animation: fadeInUp 0.8s ease 0.4s both;
}

.download-buttons {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
    margin-bottom: 24px;
}

.download-btn {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 20px 24px;
    border: 2px solid var(--border-color);
    border-radius: 16px;
    background: white;
    cursor: pointer;
    transition: all 0.3s ease;
    font-family: inherit;
}

.download-btn:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

.ios-btn:hover {
    border-color: #000000;
    background: linear-gradient(135deg, #000000 0%, #434343 100%);
}

.ios-btn:hover .btn-icon,
.ios-btn:hover .btn-content {
    color: white;
}

.android-btn:hover {
    border-color: #3DDC84;
    background: linear-gradient(135deg, #3DDC84 0%, #00C853 100%);
}

.android-btn:hover .btn-icon,
.android-btn:hover .btn-content {
    color: white;
}

.btn-icon {
    width: 48px;
    height: 48px;
    flex-shrink: 0;
    transition: all 0.3s ease;
}

.btn-content {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    text-align: left;
    transition: all 0.3s ease;
}

.btn-label {
    font-size: 18px;
    font-weight: 600;
    color: var(--text-primary);
    display: block;
}

.btn-subtitle {
    font-size: 13px;
    color: var(--text-secondary);
    display: block;
}

.device-hint {
    text-align: center;
    padding: 16px;
    background: linear-gradient(135deg, rgba(74, 144, 226, 0.1) 0%, rgba(80, 200, 120, 0.1) 100%);
    border-radius: 12px;
    font-size: 14px;
    color: var(--primary-color);
    font-weight: 500;
}

/* 功能特点区域 */
.features {
    background: white;
    border-radius: 24px;
    padding: 40px;
    margin-bottom: 40px;
    box-shadow: var(--shadow-lg);
    animation: fadeInUp 0.8s ease 0.6s both;
}

.section-title {
    font-size: 24px;
    font-weight: 600;
    color: var(--text-primary);
    text-align: center;
    margin-bottom: 32px;
    position: relative;
    padding-bottom: 16px;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 4px;
    background: var(--gradient-primary);
    border-radius: 2px;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 24px;
}

.feature-card {
    text-align: center;
    padding: 24px;
    border-radius: 16px;
    background: var(--bg-light);
    transition: all 0.3s ease;
}

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

.feature-icon {
    font-size: 48px;
    margin-bottom: 16px;
}

.feature-title {
    font-size: 18px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.feature-desc {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.6;
}

/* 使用步骤区域 */
.steps {
    background: white;
    border-radius: 24px;
    padding: 40px;
    margin-bottom: 40px;
    box-shadow: var(--shadow-lg);
    animation: fadeInUp 0.8s ease 0.8s both;
}

.steps-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 20px;
}

.step-item {
    flex: 1;
    min-width: 180px;
    text-align: center;
}

.step-number {
    width: 60px;
    height: 60px;
    margin: 0 auto 16px;
    background: var(--gradient-primary);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    font-weight: 700;
    box-shadow: 0 4px 16px rgba(102, 126, 234, 0.3);
}

.step-title {
    font-size: 16px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.step-desc {
    font-size: 14px;
    color: var(--text-secondary);
}

.step-arrow {
    font-size: 24px;
    color: var(--primary-color);
    font-weight: 300;
}

/* 常见问题区域 */
.faq {
    background: white;
    border-radius: 24px;
    padding: 40px;
    margin-bottom: 40px;
    box-shadow: var(--shadow-lg);
    animation: fadeInUp 0.8s ease 1s both;
}

.faq-list {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.faq-item {
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 20px;
    transition: all 0.3s ease;
}

.faq-item:hover {
    border-color: var(--primary-color);
    box-shadow: var(--shadow-sm);
}

.faq-question {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 16px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 12px;
}

.faq-icon {
    width: 32px;
    height: 32px;
    background: var(--gradient-primary);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
    font-weight: 700;
    flex-shrink: 0;
}

.faq-answer {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.8;
    padding-left: 44px;
}

/* 底部信息 */
.footer {
    text-align: center;
    padding: 32px 0;
    color: rgba(255, 255, 255, 0.9);
    animation: fadeIn 0.8s ease 1.2s both;
}

.footer-links {
    display: flex;
    align-items: center;
    justify-content: center;
    flex-wrap: wrap;
    gap: 12px;
    margin-bottom: 16px;
}

.footer-link {
    color: rgba(255, 255, 255, 0.9);
    text-decoration: none;
    font-size: 14px;
    transition: all 0.3s ease;
}

.footer-link:hover {
    color: white;
    text-decoration: underline;
}

.footer-divider {
    color: rgba(255, 255, 255, 0.5);
}

.copyright {
    font-size: 13px;
    color: rgba(255, 255, 255, 0.7);
}

/* 动画定义 */
@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

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

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

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

/* 响应式设计 */
@media (max-width: 768px) {
    .container {
        padding: 70px 16px 20px;
    }

    .app-name {
        font-size: 28px;
    }

    .tagline {
        font-size: 16px;
    }

    .app-title {
        font-size: 24px;
    }

    .download-section,
    .features,
    .steps,
    .faq {
        padding: 24px 20px;
        border-radius: 16px;
    }

    .download-buttons {
        grid-template-columns: 1fr;
    }

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

    .steps-container {
        flex-direction: column;
    }

    .step-arrow {
        transform: rotate(90deg);
    }

    .section-title {
        font-size: 20px;
    }

    .language-switch {
        top: 16px;
        right: 16px;
    }

    .footer-links {
        flex-direction: column;
        gap: 8px;
    }

    .footer-divider {
        display: none;
    }
}

@media (max-width: 480px) {
    .app-name {
        font-size: 24px;
    }

    .logo-placeholder {
        font-size: 36px;
    }

    .app-icon {
        width: 100px;
        height: 100px;
    }

    .icon-text {
        font-size: 28px;
    }

    .download-btn {
        padding: 16px 20px;
    }

    .btn-icon {
        width: 40px;
        height: 40px;
    }

    .btn-label {
        font-size: 16px;
    }
}

/* 打印样式 */
@media print {
    body {
        background: white;
    }

    .language-switch,
    .download-buttons {
        display: none;
    }
}