/* ======================
   RESET + BODY
====================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: Arial, sans-serif;
    background: #f2f2f2;
}

/* ======================
   HEADER + MENU
====================== */
header {
    background: #cddc39;
    padding: 15px;
    text-align: center;
}

header nav a {
    margin: 0 10px;
    text-decoration: none;
    color: black;
    font-weight: bold;
}

/* ======================
   LAYOUT CHÍNH
====================== */
.container {
    display: flex;
}

/* ======================
   DANH SÁCH SẢN PHẨM
====================== */
.products {
    width: 75%;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
    padding: 20px;
}

/* ======================
   CARD SẢN PHẨM
====================== */
.product-card {
    background: white;
    border-radius: 8px;
    padding: 15px;
    text-align: center;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.product-card img {
    width: 100%;
    border-radius: 5px;
}

.product-card h3 {
    margin: 10px 0;
}

.product-card p {
    color: #333;
}

/* ======================
   NÚT MUA NGAY
====================== */
.buy-btn {
    display: inline-block;
    margin-top: 12px;
    padding: 10px 18px;
    background-color: #04AA6D;
    color: white;
    text-decoration: none;
    font-size: 14px;
    border-radius: 20px;
    border: none;
    cursor: pointer;
}

.buy-btn:hover {
    background-color: #038e5c;
}

/* ======================
   SIDEBAR
====================== */
aside {
    width: 25%;
    background: #2196f3;
    color: white;
    padding: 20px;
}

aside a {
    display: block;
    color: white;
    text-decoration: none;
    margin-bottom: 10px;
}

/* ======================
   TRANG CHI TIẾT SẢN PHẨM
====================== */
.product-detail {
    display: flex;
    gap: 30px;
    padding: 30px;
}

.product-detail img {
    width: 50%;
    border-radius: 10px;
}

.detail-info {
    width: 50%;
}

.price {
    color: red;
    font-size: 20px;
    font-weight: bold;
    margin: 10px 0;
}

.back-btn {
    text-decoration: none;
    margin-right: 15px;
    font-weight: bold;
    color: #333;
}

/* ======================
   FOOTER
====================== */
footer {
    background: #333;
    color: white;
    display: flex;
    justify-content: space-around;
    padding: 20px;
}

/* ======================
   RESPONSIVE MOBILE
====================== */
@media (max-width: 768px) {

    .container {
        flex-direction: column;
    }

    .products {
        width: 100%;
        grid-template-columns: 1fr;
    }

    aside {
        width: 100%;
    }

    .product-detail {
        flex-direction: column;
    }

    .product-detail img,
    .detail-info {
        width: 100%;
    }

    footer {
        flex-direction: column;
        text-align: center;
        gap: 10px;
    }
}