* { margin: 0; padding: 0; box-sizing: border-box; }
body {
    font-family: Microsoft YaHei, PingFang SC, sans-serif;
    background: #f0f2f5;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* 顶部标题 */
.top-head {
    background: linear-gradient(135deg, #1E90FF 0%, #1E90FF 100%);
    color: #fff;
    padding: 16px 40px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 12px rgba(0,0,0,0.15);
}
.site-title {
    font-size: 28px;
    font-weight: bold;
    letter-spacing: 8px;
}
.login-link {
    color: #fff;
    text-decoration: none;
    font-size: 14px;
    padding: 8px 20px;
    border: 1px solid rgba(255,255,255,0.5);
    border-radius: 4px;
    transition: all 0.3s;
}
.login-link:hover {
    background: rgba(255,255,255,0.15);
    border-color: #fff;
}

/* 主区域 */
.main-wrap {
    flex: 1;
    display: flex;
    max-width: 1200px;
    margin: 30px auto;
    gap: 24px;
    padding: 0 20px;
    width: 100%;
}

/* 左侧菜单 */
.btn-group {
    width: 160px;
    display: flex;
    flex-direction: column;
    gap: 8px;
    flex-shrink: 0;
}
.menu-btn {
    display: block;
    padding: 12px 16px;
    background: #fff;
    color: #333;
    text-decoration: none;
    border-radius: 6px;
    font-size: 14px;
    text-align: center;
    box-shadow: 0 1px 4px rgba(0,0,0,0.08);
    transition: all 0.2s;
}
.menu-btn:hover {
    background: #1E90FF;
    color: #fff;
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(30,60,114,0.3);
}

/* 中间大图 */
.banner-box {
    flex: 1;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 2px 12px rgba(0,0,0,0.1);
    background: #ddd;
    min-height: 400px;
}
.banner-box img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

/* 页脚 */
footer {
    text-align: center;
    padding: 20px;
    color: #999;
    font-size: 12px;
    border-top: 1px solid #e8e8e8;
    background: #fff;
    margin-top: auto;
}
footer p { margin: 4px 0; }