title: Bulma: Responsive buttons and spacing helpers are missing
body: <p>I know the classes which I can add to tags, but how to do it responsive? For example, I want to reduce the button size on mobiles. How can I do that with Bulma? I would like to use something readily available, for instance classes <code>is-small</code> or <code>is-medium</code>, instead style each parameter in a standard way.</p>
  <p>In the example below, I would like to reduce the size of the buttons in mobile. I enclose simple gallery with buttons styled by Bulma's class <code>is-primary</code>.</p>
  <p>By the way, is there any option to add margin or padding directly by Bulma (like in Bootstrap)? I didn't find it in the docs.</p>
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>function show(index) {
    document
      .querySelectorAll(".custom-image")
      .forEach(item =&gt; (item.style.display = "none"));
  
    document.querySelectorAll(".custom-image")[index].style.display =
      "block";
  }
  document.querySelectorAll(".custom-image")[0].style.display = "block";</code></pre>
  <pre class="snippet-code-css lang-css prettyprint-override"><code>body {
    width: 100vw;
    height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    background-color: grey;
  }
  
  body .box {
    max-width: 70vw;
    box-shadow: 26px 25px 55px -4px #413e41;
  }
  
  body .box:not(:first-child) {
    margin-top: 2rem;
  }
  
  body .custom-image {
    width: 100%;
    display: none;
  }
  
  body button:not(:first-child) {
    margin-left: 1rem;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/bulma/0.7.2/css/bulma.min.css" /&gt;
  
  &lt;div class="box"&gt;
    &lt;div class="custom-image "&gt;
      &lt;img src="https://cdn.pixabay.com/photo/2017/02/01/22/02/mountain-landscape-2031539_960_720.jpg" alt="" /&gt;
    &lt;/div&gt;
    &lt;div class="custom-image"&gt;
      &lt;img src="https://cdn.pixabay.com/photo/2013/10/02/23/03/dawn-190055_960_720.jpg" alt="" /&gt;
    &lt;/div&gt;
    &lt;div class="custom-image"&gt;
      &lt;img src="https://cdn.pixabay.com/photo/2018/12/29/23/49/rays-3902368_960_720.jpg" alt="" /&gt;
    &lt;/div&gt;
  &lt;/div&gt;
  &lt;div class="box"&gt;
    &lt;button onclick="show(0)" class="button is-primary "&gt;1&lt;/button&gt;
    &lt;button onclick="show(1)" class="button is-primary "&gt;2&lt;/button&gt;
    &lt;button onclick="show(2)" class="button is-primary "&gt;3&lt;/button&gt;
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>