输入组

<!-- BASIC INPUT GROUPS -->
        <div class="input-group mb-3">
            <div class="input-group-prepend">
                <span class="input-group-text">@</span>
            </div>
            <input class="form-control" type="text" placeholder="Username">
        </div>

        <br>

        <div class="input-group mb-3">
            <input class="form-control" type="text" placeholder="Username">
            <div class="input-group-append">
                <span class="input-group-text">@something.com</span>
            </div>
        </div>

        <br>

        <label for="basic-url">Custom URL</label>
        <div class="input-group mb-3">
            <div class="input-group-prepend">
                <span class="input-group-text">https://something.com/member/</span>
            </div>
            <input class="form-control" type="text">
        </div>

        <br>

        <div class="input-group mb-3">
            <div class="input-group-prepend">
                <span class="input-group-text">$</span>
            </div>
            <input class="form-control" type="text">
            <div class="input-group-append">
                <span class="input-group-text">.00</span>
            </div>
        </div>

        <br>

        <!-- CHECKBOX -->
        <div class="input-group mb-3">
            <div class="input-group-prepend">
                <div class="input-group-text">
                    <input type="checkbox">
                </div>
            </div>
            <input class="form-control" type="text">
        </div>

        <br>

        <!-- RADIO -->
        <div>
            <div>
                <div>
                    <input type="radio">
                </div>
            </div>
            <input type="text">
        </div>

        <br>

        <!-- MULTIPLE INPUTS -->
        <div class="input-group mb-4">
            <div class="input-group-prepend">
                <span class="input-group-text" id="">Name & Email</span>
            </div>
            <input type="text" placeholder="Full Name">
            <input type="email" placeholder="Email">
        </div>

        <br>

        <!-- BUTTON ADDONS -->
        <div class="input-group mb-4">
            <input class="form-control" type="text" placeholder="Find By Name...">
            <div class="input-group-append">
                <button class="btn btn-outline-secondary" type="button">Search</button>
            </div>
        </div>