/* Base Styles */
body {
    font-family: 'Poppins', sans-serif;
    margin: 0;
    padding: 0;
    background-color: #f4f7f9;
    color: #333;
    line-height: 1.6;
    padding-bottom: 90px; /* Space for the fixed WhatsApp button */
    font-size: 16px; /* 基础字体大小 */
}

.container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px 0;
}

h1, h2, h3 {
    font-weight: 700;
    color: #007bff; /* Primary color: Blue for trust */
}

/* Header/Navigation */
header {
    background-color: #ffffff;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

header h1 {
    color: #28a745; 
    margin: 0;
    font-size: 1.8em;
    float: left;
}

header nav {
    float: right;
    line-height: 40px;
}

header nav a {
    color: #555;
    text-decoration: none;
    margin-left: 25px;
    font-weight: 600;
}

/* Hero Section */
.hero-bg {
    background-color: #eaf4ff;
    padding: 80px 0;
    text-align: center;
}

.hero-bg h2 {
    font-size: 2.5em;
    color: #004085;
    margin-bottom: 10px;
}

.hero-bg p {
    font-size: 1.2em;
    margin-bottom: 30px;
    color: #555;
}

/* Call to Action Button (Main) */
.cta-hero {
    background-color: #ffc107; 
    color: #333;
    border: none;
    padding: 15px 30px;
    font-size: 1.2em;
    font-weight: 700;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s;
    width: auto; /* 桌面端保持自动宽度 */
}

.cta-hero:hover {
    background-color: #e0a800;
}

/* About Section */
#about {
    padding: 40px 0;
    text-align: center;
}

.grid-3 {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    margin-top: 30px;
}

.card {
    background-color: #ffffff;
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.icon {
    font-size: 3em;
    display: block;
    margin-bottom: 10px;
}

/* Footer (Compliance Section) */
footer {
    background-color: #343a40; 
    color: #adb5bd;
    padding: 30px 0;
    text-align: center;
}

.compliance-links a, .company-info {
    color: #ffffff;
    text-decoration: none;
    font-size: 0.85em;
    margin: 0 10px;
    display: inline-block;
}

.compliance-links {
    margin: 10px 0 15px;
}

/* ================================================= */
/* FIXED HUGE WHATSAPP BUTTON */
/* ================================================= */

.whatsapp-fixed-cta {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background-color: #28a745; 
    color: #ffffff;
    text-align: center;
    padding: 18px 0;
    font-size: 1.5em; 
    font-weight: 700;
    text-decoration: none;
    z-index: 1000;
    box-shadow: 0 -4px 10px rgba(0, 0, 0, 0.2);
    display: flex;
    justify-content: center;
    align-items: center;
    height: 80px; /* 确保巨大 */
}

.whatsapp-fixed-cta:hover {
    background-color: #218838; 
}

.whatsapp-fixed-cta .icon-wa {
    font-size: 1.8em;
    margin-right: 15px;
}

/* --- 政策页面的返回按钮样式 --- */
.back-button {
    display: inline-block;
    background-color: #f8f9fa; 
    color: #007bff; 
    border: 1px solid #dee2e6;
    padding: 8px 15px;
    margin-bottom: 25px;
    text-decoration: none;
    font-weight: 600;
    border-radius: 5px;
    transition: background-color 0.3s;
}

.back-button:hover {
    background-color: #e2e6ea;
    text-decoration: none;
}

/* ================================================= */
/* !!! 移动端优化 (Mobile Optimization) !!! */
/* ================================================= */

@media (max-width: 768px) {
    /* 导航栏在移动端隐藏，聚焦转化 */
    header nav {
        display: none; 
    }
    header .container {
        text-align: center; 
    }
    header h1 {
        float: none;
    }

    /* 移动端主标题和副标题优化 */
    .hero-bg h2 {
        font-size: 1.8em; 
    }
    .hero-bg p {
        font-size: 1em; 
        margin-bottom: 20px;
    }

    /* 移动端 CTA 按钮优化 */
    .cta-hero {
        width: 80%; /* 让英雄区按钮宽度更宽 */
        box-sizing: border-box;
        font-size: 1.1em;
    }

    /* 价值主张的卡片在小屏幕上堆叠 */
    .grid-3 {
        grid-template-columns: 1fr; 
        gap: 20px;
    }

    /* 固定按钮在小屏幕上的细节调整 */
    .whatsapp-fixed-cta {
        font-size: 1.2em; 
        padding: 15px 0; 
        height: 70px; 
    }

    .whatsapp-fixed-cta .icon-wa {
        font-size: 1.5em;
        margin-right: 10px;
    }
}