fixed table header, border not sticking-CodePudding

i have a table that i made in html/css, i made the header of the table freeze by putting position: sticky and top: 0. this works, but the border that i have on the bottom of header does not stick, it scrolls with the content. How can i make the border on the header frozen like the header is? I would tell you what i have tried, but honestly i am still new to css and do not even know where to start debugging this. I did not find any solutions on online that worked for my issue at least. Please help me to solve this.

<html lang="en">
    <head>
        <link rel="stylesheet" href="index.css">
        <link href="https://fonts.googleapis.com/icon?family=Material Icons" rel="stylesheet">
    </head>
    <body>
        <div id="app-header">aplog</div>
        <div id="page-header">
            <div>Invoices</div>
            <button>New Invoice</button>
        </div>
        <div id="contents">
            <div id="searchbar">
                <input type="search" placeholder="Search ....">
                <div >tune</div>
                <div >download</div>
            </div>
            <div id="table-wrapper">
                <table>
                    <thead>
                        <tr>
                            <th>invoice#</th>
                            <th>vendor</th>
                            <th>date</th>
                            <th>po</th>
                            <th>amount</th>
                        </tr>
                    </thead>
                    <tbody id="tbody"></tbody>
                </table>
            </div>
        </div>
        <script src="index.js"></script>
    </body>
</html>

* {
    margin: 0;
    padding: 0;
}

body {
    width: 100vw;
    height: 100vh;
    user-select: none;
    display: grid;
    grid-template-rows: auto auto 1fr;
    background-color: #E9E9E9;
}

#app-header {
    padding: 1rem 1rem 1rem 1rem;
    font-weight: bold;
    background-color: #003469;
    color: white;
}

#page-header {
    padding: 1rem 1rem 1rem 1rem;
    font-weight: bold;
    font-size: 1.5rem;
    display: flex;
    justify-content: space-between;
}

button {
    padding: .25rem .5rem .25rem .5rem;
}

#contents {
    background-color: white;
    margin: 0rem 1rem 1rem 1rem;
    border-radius: 5px;
    border: 1px solid lightgray;
    display: grid;
    grid-template-rows: auto 1fr;
    overflow: hidden;
}

#searchbar {
    padding: 1rem;
    border-bottom: 1px solid lightgray;
}

#table-wrapper {
    overflow-y: auto;
}

table {
    width: 100%;
    border-collapse: collapse;
}

th {
    background-color: #F5F5F5;
    border-bottom: 1px solid lightgray;
}

th, td {
    padding: 1rem 1rem 1rem 1rem;
}


input[type="search"] {
    border: 0;
    outline: 0;
    width: 100%;
}


#searchbar {
    display: grid;
    grid-template-columns: 1fr auto auto;
    gap: .5rem;
}

thead, th {
    position: sticky;
    top: 0;
}

td {
    border-bottom: 1px solid lightgray;
}

#table-wrapper::-webkit-scrollbar {
    width: 0;
}

tr:hover {
    background-color: steelblue;
}


th, td {
    text-align: left;
}

th:last-child, td:last-child {
    text-align: right;
}

CodePudding user response：

You should change the value of border-collapse:

table {
    border-collapse: separate;
 }

CodePudding user response：

try position : fixed on header.