/*ví dụ*/
    #header{
        height: 200px;
        border-style: solid;
    }
    #menu{
        background-color: aquamarine;
        height: 50px;
        ul{
            justify-content: center;
            display: flex;
            gap: 100px;
        }
        
    }
    .sp{
        width: 350px;
        height: 250px;
        box-sizing: border-box;
        border: solid;
        float: left;
        margin: 12px;
        border-radius: 15px;
        padding: 20px;
    }
    p{
        font-size: 12pt;
        text-shadow: 2px 2px 4px rgba(255,0,0,0.5);
    }
    h1{
        font-size: 20pt;
        text-shadow: -2px -2px 4px rgba(6, 119, 100, 0.5);
        color: rgb(16, 194, 155)
    }