pico/scss/layout/_container.scss

@if ($enable-class-container and $enable-classes) {

/**
 * Container
 */

  .container,
  .container-fluid {
    width: 100%;
    margin-right: auto;
    margin-left: auto;
    padding-right: var(--spacing-gutter);
    padding-left: var(--spacing-gutter);
  }

  .container {

    @if map-get($breakpoints, "sm") and $enable-viewport {
      @media (min-width: map-get($breakpoints, "sm")) {
        max-width: map-get($viewports, "sm");
        padding-right: 0;
        padding-left: 0;
      }
    }

    @if map-get($breakpoints, "md") and $enable-viewport {
      @media (min-width: map-get($breakpoints, "md")) {
        max-width: map-get($viewports, "md");
      }
    }

    @if map-get($breakpoints, "lg") and $enable-viewport {
      @media (min-width: map-get($breakpoints, "lg")) {
        max-width: map-get($viewports, "lg");
      }
    }

    @if map-get($breakpoints, "xl") and $enable-viewport {
      @media (min-width: map-get($breakpoints, "xl")) {
        max-width: map-get($viewports, "xl");
      }
    }
  }
}