*{margin:0;padding:0;box-sizing:border-box;}
body{font-family:"Microsoft Yahei",sans-serif;background:#f8f9fa;}

/* 三栏布局 */
.three-column-container{max-width:1200px;margin:30px auto;padding:0 20px;display:flex;gap:20px;align-items:flex-start;}
.left-seckill{flex:0 0 25%;}
.middle-notice{flex:0 0 50%;background:#fff;border-radius:8px;box-shadow:0 2px 8px rgba(0,0,0,.08);padding:20px;}
.right-course{flex:0 0 25%;max-height:700px;overflow-y:auto;display:flex;flex-direction:column;gap:20px;}
.right-course::-webkit-scrollbar{width:6px;}
.right-course::-webkit-scrollbar-thumb{background:#ddd;border-radius:3px;}

.right-panel{background:#fff;border-radius:8px;box-shadow:0 2px 8px rgba(0,0,0,.08);padding:20px;}
.section-title{font-size:18px;font-weight:600;margin-bottom:16px;padding-bottom:8px;border-bottom:2px solid #e8f3ff;}

/* 秒杀 */
.seckill-section{background:#fff;border-radius:8px;box-shadow:0 2px 8px rgba(0,0,0,.08);padding:20px;max-height:700px;overflow-y:auto;}
.seckill-section::-webkit-scrollbar{width:6px;}
.seckill-section::-webkit-scrollbar-thumb{background:#ddd;border-radius:3px;}
.seckill-course-list{display:flex;flex-direction:column;gap:16px;}
.course-card{border:1px solid #eef1f5;border-radius:8px;overflow:hidden;transition:all .3s;background:#fff;cursor:pointer;}
.course-card:hover{box-shadow:0 8px 16px rgba(0,0,0,.08);transform:translateY(-2px);border-color:#165DFF;}
.course-img{height:140px;background:#f5f7fa;display:flex;align-items:center;justify-content:center;position:relative;}
.course-img img{width:100%;height:100%;object-fit:cover;}
.seckill-tag{position:absolute;top:8px;left:8px;background:#ff4d4f;color:#fff;font-size:12px;padding:2px 6px;border-radius:3px;}
.course-info{padding:12px;}
.course-title{font-weight:600;font-size:14px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;}
.course-meta{font-size:12px;color:#888;display:flex;justify-content:space-between;margin:6px 0;}
.course-price{font-size:16px;color:#e64340;font-weight:bold;}

/* 公告列表 */
.notice-item{padding:15px 0;border-bottom:1px solid #eee;display:flex;justify-content:space-between;align-items:center;cursor:pointer;}
.notice-item:hover{color:#165DFF;}
.notice-title{flex:1;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;margin-right:10px;}
.notice-time{font-size:12px;color:#999;white-space:nowrap;}
.empty-data{text-align:center;color:#999;padding:40px 0;}

@media(max-width:992px){
    .three-column-container{flex-direction:column;}
    .left-seckill,.middle-notice,.right-course{width:100%;flex:none;}
}