body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #fff;
    margin: 0;
    padding: 40px;
    color: #333;
}

.khung-trang {
    max-width: 1200px;
    margin: 50px auto;
    display: flex;
    gap: 30px;
}

/* Menu bên trái */
.thanh-ben-trai {
    width: 250px;
    flex-shrink: 0;
}

.danh-sach-menu {
    list-style: none;
    padding: 0;
    margin: 0;
    border: 1px solid #eee;
}

.danh-sach-menu li {
    border-bottom: 1px solid #eee;
}

.danh-sach-menu li a {
    display: block;
    padding: 15px 20px;
    text-decoration: none;
    color: #555;
    font-size: 14px;
}

.danh-sach-menu li.muc-dang-chon {
    border-left: 4px solid #000;
    background-color: #f9f9f9;
}

.danh-sach-menu li.muc-dang-chon a {
    font-weight: bold;
    color: #000;
}

/* Nội dung chính */
.noi-dung-chinh {
    flex-grow: 1;
}

.tieu-de-trang {
    font-size: 26px;
    margin-top: 0;
    margin-bottom: 30px;
}

.bo-loc-hien-thi {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 14px;
    margin-bottom: 20px;
}

.o-chon-so-luong {
    padding: 5px;
    border: 1px solid #ccc;
    margin: 0 5px;
}

/* Lưới sản phẩm */
.luoi-san-pham {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 20px;
    margin-bottom: 40px;
}

.the-san-pham {
    text-align: left;
}

.khung-anh {
    background-color: #f6f6f6;
    padding: 20px;
    margin-bottom: 15px;
    width: 200px;
}

.khung-anh img {
    width: 100%;
    height: auto;
    mix-blend-mode: multiply; /* Giúp ảnh nền trắng tiệp với nền xám nhẹ */
}

.ten-giay {
    font-size: 13px;
    font-weight: normal;
    margin: 0 0 5px 0;
    color: #444;
}

.gia-tien {
    font-weight: bold;
    font-size: 14px;
    margin: 0;
}

/* Nút bấm */
.nhom-nut-bam {
    display: flex;
    gap: 10px;
    border-top: 1px solid #eee;
    padding-top: 20px;
}

.nut-den {
    background-color: #000;
    color: #fff;
    border: 1px solid #000;
    padding: 10px 25px;
    font-weight: bold;
    text-transform: uppercase;
    cursor: pointer;
}

.nut-trang {
    background-color: #fff;
    color: #000;
    border: 1px solid #000;
    padding: 10px 25px;
    font-weight: bold;
    text-transform: uppercase;
    cursor: pointer;
}

/* Responsive */
@media (max-width: 900px) {
    .khung-trang {
        flex-direction: column;
    }
    .thanh-ben-trai {
        width: 100%;
    }
}