index.css

body{
    width: 100%;
    height: 100%;
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    background-color: black;
}
.header{
    width: 100%;
    height: 250px;
    margin: 0%;
    background-color:#e5e5e5;
    font-size: 1em;
}
.header h1{
    width: 100%;
    height:40px;
    text-align: center;
    font: 800;
    font-size: 2em;
    position: relative;
    top: 80px;
    margin: 0%;
    letter-spacing: 10px;
}
.menu{
    width: 100%;
    height: 100px;
    display: flex;
    box-sizing: border-box;
}
.menu .item{
    all: unset;
    width: 50%;
    height: 40px;
    background-color:rgb(48, 47, 47);
    margin-top: -100px;
    margin-left: 25%;
    font-size: 20px;
    color:white;
    display: block;
}
.listcontainer{
    width: 50%;
    height: auto;
    margin: -130px 0%;
    margin-left: 25%;
    background-color: rgb(48, 47, 47);
    color: #e5e5e5;
    background-color: gr;
}
.item-row:nth-of-type(1){
    margin-top: 0%;
    text-align: center;
}
.item-row{
    width: 100%;
    height: 45px;
    display: flex;
    border-bottom: 2px solid rgba(255, 255, 255, 0.603);
}
.serialNo,.serialNo-header{
    width: 10%;
    height: 45px;
    text-align: center;
    font-size: 1.2em;
    box-sizing: border-box;
    line-height: 45px; 
}
.item-row .item-name-header{
    width: 90%;
    height: 45px;
    font-size:1.3rem;
    background-color: grey;
    line-height: 45px;
}
.item-row .item-name{
    width: 90%;
    height: 45px;
    font-size:1.3rem;
    background-color: rgb(150, 140, 140);
    line-height: 45px;
    padding-left: 10px;
}
.PopUp{
    display: none;
    top:0;
    position: absolute;
    margin-top: 10%;
    height: 100%;
    width: 100%;
    text-align: center;
    /* background-color: aqua; */
}
.window{
    margin: auto;
    width: 40%;
    height: 300px;
    background-color: grey;
    font-size: 1em;
}
.window h6{
    text-align: center;
    all: unset;
    top: 80px;
    position: relative;
}
.window button{
    display: block;
    position: relative;
    top: 100px;
    left: 20%;
    width: 60%;
    margin-top: 10px;
}