:root {
    --primary: #6200EA;
    --primary-dark: #3700B3;
    --surface: #FFFFFF;
    --background: #F5F5F7;
    --text-primary: #121212;
    --text-secondary: #616161;
    --border-radius: 12px;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.12);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 25px rgba(0,0,0,0.1);
}

/* 基础重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, 
                 "PingFang SC", "Microsoft YaHei", sans-serif;
    background: var(--background);
    color: var(--text-primary);
    line-height: 1.6;
}

.app-container {
    max-width: 1200px;
    margin: 0 auto;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* 头部样式 - 修改部分 */
.app-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem 2rem;
    background: var(--surface);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 100;
}

.logo-container {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.logo-fallback {
    width: 48px;
    height: 48px;
    border-radius: var(--border-radius);
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden; /* 新增：防止图片溢出 */
    position: relative; /* 为图片绝对定位做准备 */
}

/* 新增logo图片样式 */
.logo-fallback img {
    width: 100%;
    height: 100%;
    object-fit: contain; /* 保持比例不变形 */
    position: absolute; /* 覆盖默认背景 */
}

.app-meta h1 {
    font-family: 'Rajdhani', sans-serif;
    font-weight: 700;
    font-size: 1.5rem;
    letter-spacing: -0.5px;
    color: var(--primary);
}

.app-meta p {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.download-btn {
    padding: 0.75rem 1.5rem;
    background: var(--primary);
    color: white;
    border: none;
    border-radius: 100px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    box-shadow: var(--shadow-sm);
}

.download-btn:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

/* 主要内容 */
.app-content {
    flex: 1;
    padding: 2rem;
}

.video-hero {
    margin-bottom: 3rem;
}

.video-wrapper {
    width: 100%;
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--shadow-lg);
    aspect-ratio: 16/9;
    background: #000;
}

video {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

/* 描述区域 */
.app-description {
    max-width: 800px;
    margin: 0 auto;
}

.app-description h2 {
    font-family: 'Rajdhani', sans-serif;
    font-size: 2rem;
    margin-bottom: 1.5rem;
    color: var(--primary);
    text-align: center;
}

.description-content {
    background: var(--surface);
    padding: 2rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-sm);
}

.description-content p {
    margin-bottom: 1rem;
}

.description-content ul {
    margin: 1.5rem 0;
    padding-left: 1.5rem;
}

.description-content li {
    margin-bottom: 0.75rem;
    position: relative;
}

.highlight {
    font-weight: 500;
    color: var(--primary);
    text-align: center;
    margin-top: 1.5rem;
}

/* 页脚 */
.app-footer {
    text-align: center;
    padding: 1.5rem;
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.app-footer a {
    color: inherit;
    text-decoration: none;
    margin: 0 0.5rem;
}

.app-footer a:hover {
    text-decoration: underline;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .app-header {
        padding: 1rem;
    }
    
    .app-content {
        padding: 1rem;
    }
    
    .video-wrapper {
        aspect-ratio: 16/9;
    }
    
    .app-description h2 {
        font-size: 1.75rem;
    }
}

@media (max-width: 480px) {
    .app-header {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }
    
    .logo-container {
        flex-direction: column;
    }
    
    .download-btn {
        width: 100%;
    }
    
    .description-content {
        padding: 1.5rem;
    }
}