Editing appearance 重写 select 样式

<!DOCTYPE html>
<html>

<head>
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta charset="utf-8" />
    <title>appearance 重写 select 样式</title>
</head>

<body>
    <div>
        <h3>appearance 重写 select 样式</h3>
        
        <select>
            <option>select (default)</option>
            <option>select item</option>
        </select>

        <select class="custom-form">
            <option>custom-form</option>
            <option>use bootstrap</option>
        </select>

        <select class="custom-select">
            <option>custom-select</option>
            <option>use bootstrap</option>
        </select>

    </div>
</body>

</html>

html, body {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

div {
    padding: 15px;
}

select {
    margin: 10px 0;
}

.custom-form {
    display: block;
    width: 100%;
    padding: .375rem 2.25rem .375rem .75rem;
    font-size: 1rem;
    font-weight: 400;
    line-height: 1.5;
    color: #212529;
    background-color: #fff;
    background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16'%3e%3cpath fill='none' stroke='%23343a40' stroke-linecap='round' stroke-linejoin='round' stroke-width='2' d='M2 5l6 6 6-6'/%3e%3c/svg%3e");
    background-repeat: no-repeat;
    background-position: right .75rem center;
    background-size: 16px 12px;
    border: 1px solid #ced4da;
    border-radius: .25rem;
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
}

.custom-select {
    display: inline-block;
    width: 100%;
    height: calc(1.5em + .75rem + 2px);
    padding: .375rem 1.75rem .375rem .75rem;
    font-size: 1rem;
    font-weight: 400;
    line-height: 1.5;
    color: #495057;
    vertical-align: middle;
    background:#fff url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' width='4' height='5' viewBox='0 0 4 5'%3e%3cpath fill='%23343a40' d='M2 0L0 2h4zm0 5L0 3h4z'/%3e%3c/svg%3e") right .75rem center/8px 10px no-repeat;
    border: 1px solid #ced4da;
    border-radius: .25rem;
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
}