/* 基础设置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
}

body {
    background-color: #f0f2f5;
    font-family: -apple-system, "PingFang SC", "Helvetica Neue", sans-serif;
    color: #333;
}

.page-container {
    max-width: 480px;
    margin: 0 auto;
    background-color: #fff;
    min-height: 100vh;
    padding-bottom: 90px;
    box-shadow: 0 0 15px rgba(0,0,0,0.08);
}

/* --- 头部背景完整显示优化 --- */
.hero {
    background-color: #000;
	
}

.hero-img-placeholder {
    width: 100%;
	height: 360px;
    /* 关键点：设置宽高比，防止图片被裁剪。假设原图是 16:9 */
    aspect-ratio: 16 / 9; 
    background-image: url('img/top.jpg'); 
    background-size: contain;    /* 完整显示 */
    background-position: center;
    background-repeat: no-repeat;
    position: relative;
}

.hero-badge {
    position: absolute;
    bottom: 10px;
    right: 10px;
    background: rgba(0,0,0,0.6);
    color: #fff;
    padding: 3px 10px;
    font-size: 11px;
    border-radius: 4px;
}

/* --- 信息区美化（增加背景色和卡片感） --- */
.hero-info {
    padding: 20px 15px;
    /* 增加一个非常淡的暖金背景色，提升高级感 */
    background: linear-gradient(180deg, #ffffff 0%, #fffbf0 100%);
    border-bottom: 8px solid #f0f2f5; /* 增加分割感 */
}

.course-title {
    font-size: 20px;
    font-weight: bold;
    color: #1a1a1a;
    line-height: 1.4;
    margin-bottom: 10px;
}

.icon-medal { margin-right: 5px; }

.tagline {
    font-size: 13px;
    color: #666;
    line-height: 1.6;
    margin-bottom: 18px;
    padding-left: 5px;
    border-left: 3px solid #FBC02D; /* 侧边金条 */
}

/* 价格与报名栏美化 */
.price-bar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: #fff;
    padding: 12px;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.04);
}

.price-num {
    font-size: 28px;
    font-weight: 800;
    color: #e74c3c;
    letter-spacing: -1px;
}

.unit { font-size: 14px; color: #e74c3c; font-weight: bold; }

.old-price {
    font-size: 13px;
    color: #999;
    text-decoration: line-through;
    margin-left: 6px;
}

.stats {
    font-size: 12px;
    color: #d97706; /* 暖橙色 */
    background: #fffbeb;
    padding: 4px 8px;
    border-radius: 4px;
    font-weight: 500;
}

/* --- 选项卡 & 详情图修复 --- */
.tabs {
    display: flex;
    background: #fff;
    position: sticky;
    top: 0;
    z-index: 100;
    border-bottom: 1px solid #eee;
}

.tab {
    flex: 1;
    text-align: center;
    padding: 15px 0;
    font-size: 15px;
    color: #666;
    cursor: pointer;
}

.tab.active {
    color: #333;
    font-weight: bold;
}

.tab.active::after {
    content: "";
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 20px;
    height: 3px;
    background: #FBC02D;
}

.tab-pane { display: none; }
.tab-pane.active { display: block; }

/* 详情图片铺满不溢出 */
.detail-images img {
    width: 100%;
    height: auto;
    display: block;
}

/* --- 手风琴交互样式 --- */
#syllabus { padding: 15px; }
.accordion-item { border-bottom: 1px solid #f5f5f5; }
.accordion-header { padding: 15px 0; display: flex; align-items: center; cursor: pointer; }
.chapter-num { color: #FBC02D; font-weight: bold; margin-right: 12px; }
.chapter-title { flex: 1; font-size: 14px; font-weight: 500; }
.arrow { 
    width: 8px; height: 8px; 
    border-right: 2px solid #ccc; border-bottom: 2px solid #ccc; 
    transform: rotate(45deg); transition: 0.3s;
}
.accordion-item.open .arrow { transform: rotate(-135deg); }
.accordion-body { max-height: 0; overflow: hidden; transition: 0.3s ease-out; background: #fafafa; }
.accordion-item.open .accordion-body { max-height: 500px; }
.accordion-body ul { list-style: none; padding: 10px 10px 15px 40px; }
.accordion-body li { padding: 6px 0; font-size: 13px; color: #666; border-bottom: 1px dashed #f0f0f0; }

/* --- 底部固定按钮 --- */
.bottom-footer {
    position: fixed;
    bottom: 0;
    width: 100%;
    max-width: 480px;
    background: #fff;
    padding: 12px 20px;
    border-top: 1px solid #eee;
    z-index: 200;
}

.buy-btn {
    width: 100%;
    background: linear-gradient(90deg, #4facfe 0%, #00f2fe 100%); /* 渐变蓝 */
    background: #3B82F6;
    color: #fff;
    border: none;
    padding: 14px;
    border-radius: 50px; /* 圆角矩形 */
    font-size: 16px;
    font-weight: bold;
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.3);
}