*{
    box-sizing:border-box;
}

body{
    margin:0;
    font-family:Arial;
    background:#f5f5f5;
}

header{
    background:#222;
    color:#fff;
    padding:25px;
    text-align:center;
}

header h1{
    margin:0;
    font-size:40px;
}

.cover{
    width:100%;
    height:420px;
    object-fit:cover;
    display:block;
}

.section{
    padding:50px 20px;
}

.tieude{
    text-align:center;
    font-size:40px;
    margin-bottom:40px;
    color:#4b0082;
}

.khung-menu{
    max-width:1300px;
    margin:auto;
    display:grid;
    grid-template-columns:repeat(3,1fr);
    gap:25px;
}

.box{
    background:#fff;
    border-radius:18px;
    overflow:hidden;
    text-decoration:none;
    color:#333;
    transition:0.3s;
    box-shadow:0 5px 20px rgba(0,0,0,0.08);
}

.box:hover{
    transform:translateY(-5px);
    box-shadow:0 10px 30px rgba(0,0,0,0.15);
}

.box img{
    width:100%;
    height:220px;
    object-fit:cover;
}

.noidung{
    padding:25px;
}

.noidung h2{
    margin:0 0 15px;
    color:#4b0082;
    font-size:28px;
}

.noidung p{
    margin:0;
    line-height:28px;
    color:#555;
}

.sanpham{
    background:#fff;
}

@media(max-width:1000px){

    .khung-menu{
        grid-template-columns:repeat(2,1fr);
    }

}

@media(max-width:700px){

    .khung-menu{
        grid-template-columns:1fr;
    }

    .tieude{
        font-size:30px;
    }

}