How to add space between flex children if their widths add up to 100% of the container

Question

I have a flex container with 4 children and depending on the width of the screen, I want 1,2, or 3 posts to be displayed per row. I'm trying to set the widths of the posts at 100%, 50%, and 33.3% depending on the view but my question is - if the posts add up to 100% then how can I add spacing between the posts? Currently they're overflowing into the next row.

I've include my code below, but I want it to look similar to the posts section here: https://carney.co/daily-carnage/.

I've tried to add margin and padding but this causes the posts to overflow into the next row.

  .container {
  max-width: 1140px;
  padding-left: 2rem;
  padding-right: 2rem;
  margin-right: auto;
  margin-left: auto;
  box-sizing: border-box;
  display: flex;
  flex-wrap: wrap;
}

article {
  box-shadow: 0 0 0.6rem 0.25rem rgba(0, 0, 0, .1);
  margin: 2rem 0;
  width: 100%;
}

.post-meta-and-title {
  padding: 2rem 1.5rem 0;
}

.post-meta {
  font-size: .7rem;
}

.post-title {
  font-size: 1.25rem;
}

.post-description {
  padding: 0 1.5rem;
}

footer {
  position: relative;
  padding: 0 1.5rem 2rem;
}

.btn {
  background-image: linear-gradient(150deg, #ffb064 -1%, #ff6496 101%);
  color: white;
  position: absolute;
  right: -1rem;
  bottom: -1rem;
  padding: .5rem 2rem;
  line-height: 1.5;
}

.author-name {
  display: inline;
}

span {
  padding: 0 .4rem;
}

@media (min-width: 810px) {
  .container {
    padding: 0;
  }
  article {
    width: 50%;
  }
  @media (min-width: 1200px) {
    article {
      width: 33.3%;
      margin-right: 3rem;
    }
  }

<section class="container">
  <article>
    <header class="post-meta-and-title">
      <div class="post-meta">
        <time datetime="2019-05-09 20:00">May 9, 2019</time>
        <p class="author-name"><span>|</span>
          <a href="https://carney.co/author/adamkunes/" rel="author">Adam Kunes</a>
        </p>
      </div>
      <h2><a class="post-title" href="#">Sky High WiFi</a></h2>
    </header>

    <p class="post-description">plus – better landing pages, heatmaps, and Starbucks.</p>

    <footer>
      <a href="#" class="btn">READ MORE</a>
    </footer>
  </article>

  <article>
    <header class="post-meta-and-title">
      <div class="post-meta">
        <time datetime="2019-05-09 20:00">May 9, 2019</time>
        <p class="author-name"><span>|</span>
          <a href="https://carney.co/author/adamkunes/" rel="author">Adam Kunes</a>
        </p>
      </div>
      <h2><a class="post-title" href="#">Are you afraid of clowns?</a></h2>
    </header>

    <p class="post-description">plus – tech overload, productivity, and Tom Brady.</p>

    <footer>
      <a href="#" class="btn">READ MORE</a>
    </footer>
  </article>

  <article>
    <header class="post-meta-and-title">
      <div class="post-meta">
        <time datetime="2019-05-09 20:00">May 9, 2019</time>
        <p class="author-name"><span>|</span>
          <a href="https://carney.co/author/adamkunes/" rel="author">Adam Kunes</a>
        </p>
      </div>
      <h2><a class="post-title" href="#">It's time to get real folks</a></h2>
    </header>

    <p class="post-description">plus – sell more event tickets, and faster feedback.</p>

    <footer>
      <a href="#" class="btn">READ MORE</a>
    </footer>
  </article>

  <article>
    <header class="post-meta-and-title">
      <div class="post-meta">
        <time datetime="2019-05-09 20:00">May 9, 2019</time>
        <p class="author-name"><span>|</span>
          <a href="https://carney.co/author/adamkunes/" rel="author">Adam Kunes</a>
        </p>
      </div>
      <h2><a class="post-title" href="#">Burger King goes plant-based</a></h2>
    </header>

    <p class="post-description">plus – how to create content for boring industries.</p>

    <footer>
      <a href="#" class="btn">READ MORE</a>
    </footer>
  </article>

</section>

I want 1,2, or 3 posts to be displayed per row depending on the screen size. The widths of the posts should be set to 100%, 50%, and 33.3% but there should also be space in between them like on https://carney.co/daily-carnage/.

Answer 1

What I've done in the past is wrap your child elements each in their own container then have that be 33.3% width or whatever then give it padding to add space between the actual children. Margin is added in addition to the width (so its actually 33.33% + 20px). Padding doesn't add to width. So something like this maybe

Another possibility is using width calc. so

width: calc(33.333% - 20px);

Just don't use calc with flex basis. It gets weird in IE.

Answer 2

You can use justify-content on the .container and calculate the width you want minus the spacing you want.

.container {
  max-width: 1140px;
  padding-left: 2rem;
  padding-right: 2rem;
  margin-right: auto;
  margin-left: auto;
  box-sizing: border-box;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between; /* ADDED */
}

article {
  box-shadow: 0 0 0.6rem 0.25rem rgba(0, 0, 0, .1);
  margin: 2rem 0;
  width: 100%;
}

.post-meta-and-title {
  padding: 2rem 1.5rem 0;
}

.post-meta {
  font-size: .7rem;
}

.post-title {
  font-size: 1.25rem;
}

.post-description {
  padding: 0 1.5rem;
}

footer {
  position: relative;
  padding: 0 1.5rem 2rem;
}

.btn {
  background-image: linear-gradient(150deg, #ffb064 -1%, #ff6496 101%);
  color: white;
  position: absolute;
  right: -1rem;
  bottom: -1rem;
  padding: .5rem 2rem;
  line-height: 1.5;
}

.author-name {
  display: inline;
}

span {
  padding: 0 .4rem;
}

@media (min-width: 810px) {
  .container {
    padding: 0;
  }
  article {
    width: calc(50% - 4rem);  /* USE CALC */
  }
  @media (min-width: 1200px) {
    article {
      width: calc(33.3% - 4rem);  /* USE CALC */
    }
  }

<section class="container">
  <article>
    <header class="post-meta-and-title">
      <div class="post-meta">
        <time datetime="2019-05-09 20:00">May 9, 2019</time>
        <p class="author-name"><span>|</span>
          <a href="https://carney.co/author/adamkunes/" rel="author">Adam Kunes</a>
        </p>
      </div>
      <h2><a class="post-title" href="#">Sky High WiFi</a></h2>
    </header>

    <p class="post-description">plus – better landing pages, heatmaps, and Starbucks.</p>

    <footer>
      <a href="#" class="btn">READ MORE</a>
    </footer>
  </article>

  <article>
    <header class="post-meta-and-title">
      <div class="post-meta">
        <time datetime="2019-05-09 20:00">May 9, 2019</time>
        <p class="author-name"><span>|</span>
          <a href="https://carney.co/author/adamkunes/" rel="author">Adam Kunes</a>
        </p>
      </div>
      <h2><a class="post-title" href="#">Are you afraid of clowns?</a></h2>
    </header>

    <p class="post-description">plus – tech overload, productivity, and Tom Brady.</p>

    <footer>
      <a href="#" class="btn">READ MORE</a>
    </footer>
  </article>

  <article>
    <header class="post-meta-and-title">
      <div class="post-meta">
        <time datetime="2019-05-09 20:00">May 9, 2019</time>
        <p class="author-name"><span>|</span>
          <a href="https://carney.co/author/adamkunes/" rel="author">Adam Kunes</a>
        </p>
      </div>
      <h2><a class="post-title" href="#">It's time to get real folks</a></h2>
    </header>

    <p class="post-description">plus – sell more event tickets, and faster feedback.</p>

    <footer>
      <a href="#" class="btn">READ MORE</a>
    </footer>
  </article>

  <article>
    <header class="post-meta-and-title">
      <div class="post-meta">
        <time datetime="2019-05-09 20:00">May 9, 2019</time>
        <p class="author-name"><span>|</span>
          <a href="https://carney.co/author/adamkunes/" rel="author">Adam Kunes</a>
        </p>
      </div>
      <h2><a class="post-title" href="#">Burger King goes plant-based</a></h2>
    </header>

    <p class="post-description">plus – how to create content for boring industries.</p>

    <footer>
      <a href="#" class="btn">READ MORE</a>
    </footer>
  </article>

</section>