/* ==========================================
   全局重置与基础设置
   ========================================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
}

body, html {
    height: 100%;
    width: 100%;
    overflow: hidden; 
}

/* ==========================================
   背景与容器布局
   ========================================== */
.background-container {
    height: 100vh;
    width: 100vw;
    background-image: url('bg.jpg'); /* 引用电脑版背景图 */
    background-size: cover;
    background-position: center;
    display: flex;
    justify-content: center;
    align-items: center;
}

/* ==========================================
   核心：毛玻璃卡片 (极致美学调整版)
   ========================================== */
.glass-card {
    /* 主观美学调整：将背景颜色透明度从 0.4 降至 0.35，使卡片更轻盈 */
    background: rgba(30, 30, 30, 0.35); 
    
    /* 核心修改点：将默认模糊度从 15px 显著降低，这里暂设定为 8px 作为实验起始值 */
    backdrop-filter: blur(8px); 
    -webkit-backdrop-filter: blur(8px); 
    
    border: 1px solid rgba(255, 255, 255, 0.08); 
    border-radius: 24px; 
    
    width: min(88%, 620px); 
    padding: 70px 60px; 
    
    text-align: center;
    color: white;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.6); 
    position: relative;
    
    opacity: 0; 
    animation: fadeUpIn 1.4s cubic-bezier(0.16, 1, 0.3, 1) forwards; 
}

/* ==========================================
   排版层级与细节雕琢
   ========================================== */
.logo {
    width: 90px; 
    height: 90px;
    border-radius: 50%;
    margin-bottom: 25px; 
    box-shadow: 0 4px 15px rgba(0,0,0,0.3); 
}

.brand-name {
    font-weight: 300; 
    font-size: 1.6rem; 
    letter-spacing: 5px; 
    color: #f0f0f0;
    margin-bottom: 15px;
}

.main-title {
    font-size: 2rem; 
    font-weight: 800; 
    letter-spacing: 2px;
    line-height: 1.3;
    color: #ffffff;
}

.highlight-text {
    color: #e0e0d0; 
    font-weight: 600;
    font-size: 0.95rem; 
    letter-spacing: 3px;
    margin-top: 35px; 
    margin-bottom: 10px; 
}

.spacer {
    height: 25px; 
}

/* ==========================================
   交互元素 (按钮与图标)
   ========================================== */
.button-group {
    display: flex;
    flex-direction: column;
    gap: 20px; 
    align-items: center;
    width: 100%; 
}

.action-btn {
    text-decoration: none;
    color: white;
    background: rgba(0, 0, 0, 0.5);
    padding: 16px 0; 
    border-radius: 40px; 
    width: 85%; 
    max-width: 380px; 
    font-size: 1.05rem; 
    font-weight: 500;
    letter-spacing: 1.5px;
    transition: all 0.4s cubic-bezier(0.16, 1, 0.3, 1); 
    border: 1px solid rgba(255,255,255,0.08);
    display: flex;
    justify-content: center;
    align-items: center;
}

.action-btn i {
    margin-right: 12px;
    font-size: 1.2rem;
}

.action-btn:hover {
    background: rgba(255, 255, 255, 0.15);
    border-color: rgba(255,255,255,0.2);
    transform: translateY(-3px);
    box-shadow: 0 10px 20px rgba(0,0,0,0.2);
}

/* 底部悬浮邮件图标 */
.email-icon {
    position: absolute;
    bottom: -35px; 
    left: 50%;
    transform: translateX(-50%);
    background: #1a1a1a;
    width: 70px; 
    height: 70px;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    border: 2px solid rgba(255,255,255,0.08);
    transition: all 0.3s ease;
}

.email-icon:hover {
    transform: translateX(-50%) translateY(-5px); 
    background: #2a2a2a;
}

.email-icon a {
    color: #e0e0d0; 
    font-size: 1.6rem; 
    text-decoration: none;
    display: flex;
    justify-content: center;
    align-items: center;
    width: 100%;
    height: 100%;
}

/* ==========================================
   动画定义
   ========================================== */
@keyframes fadeUpIn {
    0% {
        opacity: 0;
        transform: translateY(50px) scale(0.92); 
        filter: blur(15px); 
    }
    100% {
        opacity: 1;
        transform: translateY(0) scale(1); 
        filter: blur(0); 
    }
}

/* ==========================================
   移动端专属视觉与排版重构 (核心修改区)
   ========================================== */
@media screen and (max-width: 768px) {
    /* 1. 拦截默认背景，替换为专属的竖版星空图 */
    .background-container {
        background-image: url('bg-mobile.jpg');
        background-position: center center;
    }

    /* 2. 重写毛玻璃卡片参数 */
    .glass-card {
        width: 90%; 
        padding: 40px 30px; 
        border-radius: 20px;
        
        /* 核心修改点：大幅降低移动端的模糊度，使其通透清晰 */
        backdrop-filter: blur(5px); 
        -webkit-backdrop-filter: blur(5px); 
    }
    
    .logo {
        width: 70px; 
        height: 70px;
        margin-bottom: 15px;
    }
    
    .brand-name {
        font-size: 1.3rem;
    }
    
    .main-title {
        font-size: 1.5rem; 
    }
    
    .action-btn {
        width: 100%; 
        padding: 14px 0;
        font-size: 0.95rem;
    }

    /* 3. 向上收起底部邮件图标，确保可见 */
    .email-icon {
        bottom: -25px;
        width: 60px;
        height: 60px;
    }
    
    .email-icon a {
        font-size: 1.4rem;
    }
}