<nav class="navbar navbar-expand-lg navbar-light bg-light">
    <a class="navbar-brand" href="#">Gestão Clientes</a>
    <button class="navbar-toggler" type="button" data-toggle="collapse"
            data-target="#navbarSupportedContent"
            aria-controls="navbarSupportedContent"
            aria-expanded="false" aria-label="Toggle navigation">
        <span class="navbar-toggler-icon"></span>
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    <div class="collapse navbar-collapse" id="navbarSupportedContent">
        <ul class="navbar-nav mr-auto">
            <li class="nav-item active">
                <a class="nav-link" href="./index.php">Home <span class="sr-only">(current)</span></a>
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            <li class="nav-item">
                <a class="nav-link" href="./cadastro.php">Cadastrar</a>
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</nav>