/* ==========================================
   奈飞工厂 - 移动端优先样式表
   主题色: 深红色系 (#E50914, #B20710)
   ========================================== */

/* 全局重置和基础样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* 主题色 */
    --primary-color: #E50914;
    --primary-dark: #B20710;
    --primary-light: #F40612;

    /* 辅助色 */
    --secondary-color: #221F1F;
    --text-dark: #141414;
    --text-light: #FFFFFF;
    --text-gray: #666666;

    /* 背景色 */
    --bg-dark: #000000;
    --bg-light: #FFFFFF;
    --bg-gray: #F8F8F8;

    /* 阴影 */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.12);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.15);

    /* 间距 */
    --spacing-xs: 8px;
    --spacing-sm: 16px;
    --spacing-md: 24px;
    --spacing-lg: 32px;
    --spacing-xl: 48px;

    /* 圆角 */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;

    /* 过渡 */
    --transition: all 0.3s ease;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    background: var(--bg-light);
    overflow-x: hidden;
    min-height: 100vh;
}

.container {
    max-width: 100%;
    margin: 0 auto;
    padding: 0 var(--spacing-sm);
}

/* 主横幅区域 */
.hero {
    padding: var(--spacing-md) 0 var(--spacing-lg);
    background: linear-gradient(135deg, #0a0000 0%, #1a0505 50%, #0a0000 100%);
    color: var(--text-light);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at 50% 20%, rgba(229, 9, 20, 0.25) 0%, transparent 60%);
    pointer-events: none;
}

.hero .container {
    position: relative;
    z-index: 1;
}

/* Logo区域 */
.logo-section {
    text-align: center;
    padding: var(--spacing-sm) 0;
    animation: fadeInDown 0.8s ease;
}

.app-logo {
    width: 80px;
    height: 80px;
    border-radius: var(--radius-xl);
    box-shadow: 0 8px 24px rgba(229, 9, 20, 0.3);
    margin-bottom: var(--spacing-xs);
}

.app-name {
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 4px;
    background: linear-gradient(135deg, #FFFFFF 0%, #E50914 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.app-slogan {
    font-size: 14px;
    color: rgba(255, 255, 255, 0.7);
    font-weight: 400;
}

/* 下载区域 */
.download-section {
    text-align: center;
    padding: var(--spacing-md) 0;
    animation: fadeInUp 0.8s ease 0.2s both;
}

.btn-download {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    width: 100%;
    max-width: 320px;
    padding: 16px 32px;
    background: var(--primary-color);
    color: var(--text-light);
    border: none;
    border-radius: var(--radius-lg);
    font-size: 18px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: 0 4px 20px rgba(229, 9, 20, 0.4);
}

.btn-download:active {
    transform: scale(0.98);
}

.download-icon {
    width: 24px;
    height: 24px;
}

.download-tip {
    margin-top: var(--spacing-xs);
    font-size: 12px;
    color: rgba(255, 255, 255, 0.6);
}

/* 轮播图 */
.carousel {
    margin: var(--spacing-md) 0 0;
    position: relative;
    animation: fadeInUp 0.8s ease 0.4s both;
}

.carousel-container {
    position: relative;
    width: 100%;
    max-width: 400px;
    margin: 0 auto;
    aspect-ratio: 9 / 16;
    border-radius: var(--radius-xl);
    overflow: hidden;
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.5);
}

.carousel-item {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    opacity: 0;
    transition: opacity 0.5s ease;
}

.carousel-item.active {
    opacity: 1;
}

.carousel-item img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.carousel-dots {
    display: flex;
    justify-content: center;
    gap: var(--spacing-xs);
    margin-top: var(--spacing-sm);
}

.dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.3);
    cursor: pointer;
    transition: var(--transition);
}

.dot.active {
    background: var(--primary-color);
    width: 24px;
    border-radius: 4px;
}


/* 功能特色区域 */
.features {
    padding: var(--spacing-xl) 0;
    background: var(--bg-light);
}

.section-title {
    font-size: 24px;
    font-weight: 700;
    text-align: center;
    margin-bottom: var(--spacing-md);
    color: var(--text-dark);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-sm);
}

.feature-item {
    background: var(--bg-gray);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    text-align: center;
    transition: var(--transition);
}

.feature-item:active {
    transform: scale(0.98);
    background: #f0f0f0;
}

.feature-icon {
    font-size: 40px;
    margin-bottom: var(--spacing-xs);
}

.feature-item h3 {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 4px;
    color: var(--text-dark);
}

.feature-item p {
    font-size: 13px;
    color: var(--text-gray);
    line-height: 1.5;
}

/* 常见问题区域 */
.faq {
    padding: var(--spacing-xl) 0;
    background: var(--bg-gray);
}

.faq-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.faq-item {
    background: var(--bg-light);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
}

.faq-question {
    font-size: 15px;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: var(--spacing-xs);
}

.faq-answer {
    font-size: 14px;
    color: var(--text-gray);
    line-height: 1.6;
}

/* 底部 */
.footer {
    background: var(--secondary-color);
    color: var(--text-light);
    padding: var(--spacing-lg) 0;
    text-align: center;
}

.footer-text {
    font-size: 14px;
    margin-bottom: var(--spacing-xs);
    color: var(--text-light);
}

.footer-keywords {
    font-size: 12px;
    color: var(--text-gray);
}

/* SEO内容区域（隐藏但对搜索引擎可见） */
.seo-content {
    position: absolute;
    left: -9999px;
    width: 1px;
    height: 1px;
    overflow: hidden;
}

.seo-content h2,
.seo-content h3 {
    font-size: 18px;
    margin: 10px 0;
}

.seo-content p {
    margin: 10px 0;
    line-height: 1.6;
}

.seo-content ul {
    margin: 10px 0;
    padding-left: 20px;
}

.seo-content li {
    margin: 5px 0;
}

/* 返回顶部按钮 */
.back-to-top {
    position: fixed;
    bottom: 20px;
    right: 20px;
    width: 48px;
    height: 48px;
    background: var(--primary-color);
    color: var(--text-light);
    border: none;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-lg);
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
    z-index: 999;
}

.back-to-top.show {
    opacity: 1;
    visibility: visible;
}

.back-to-top:active {
    transform: scale(0.95);
}

.back-to-top svg {
    width: 24px;
    height: 24px;
}

/* 动画 */
@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);
    }
}

/* 平板适配 */
@media (min-width: 768px) {
    .container {
        max-width: 720px;
        padding: 0 var(--spacing-md);
    }

    .app-logo {
        width: 120px;
        height: 120px;
    }

    .app-name {
        font-size: 40px;
    }

    .app-slogan {
        font-size: 18px;
    }

    .carousel-container {
        max-width: 360px;
    }

    .btn-download {
        max-width: 400px;
        font-size: 20px;
        padding: 18px 40px;
    }

    .section-title {
        font-size: 28px;
    }

    .features-grid {
        grid-template-columns: repeat(4, 1fr);
        gap: var(--spacing-md);
    }

    .feature-item {
        padding: var(--spacing-lg);
    }

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

    .feature-item h3 {
        font-size: 18px;
    }

    .feature-item p {
        font-size: 14px;
    }
}

/* 桌面适配 */
@media (min-width: 1024px) {
    .container {
        max-width: 960px;
    }

    .hero {
        min-height: auto;
        padding: var(--spacing-xl) 0;
    }

    .carousel-container {
        max-width: 320px;
    }

    .btn-download:hover {
        background: var(--primary-dark);
        transform: translateY(-2px);
        box-shadow: 0 6px 24px rgba(229, 9, 20, 0.5);
    }

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

    .back-to-top:hover {
        background: var(--primary-dark);
        transform: translateY(-4px);
    }
}

/* 超小屏幕优化 */
@media (max-width: 375px) {
    .app-logo {
        width: 80px;
        height: 80px;
    }

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

    .app-slogan {
        font-size: 14px;
    }

    .carousel-container {
        max-width: 100%;
    }

    .btn-download {
        font-size: 16px;
        padding: 14px 28px;
    }

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

    .features-grid {
        gap: var(--spacing-xs);
    }

    .feature-item {
        padding: var(--spacing-sm);
    }

    .feature-icon {
        font-size: 32px;
    }

    .feature-item h3 {
        font-size: 14px;
    }

    .feature-item p {
        font-size: 12px;
    }
}