AMP & CSS

HI @2ladd,

in the classic mode you need to utilize the amp_post_template_css action of the AMP plugin. You can read more about this here: https://amp-wp.org/documentation/how-the-plugin-works/classic-templates/. You should put the code in your child theme’s functions.php. The sample code is below:

add_action( 'amp_post_template_css', 'xyz_amp_my_additional_css_styles' );

function xyz_amp_my_additional_css_styles( $amp_template ) {
  // only CSS here please...
  ?>
  /* Results widget stars */
  .rmp-amp-star::before {
    content: "★";
    font-size: 26px;
    color: #ccc;
    margin: -2px;
  }

  .rmp-amp-star-highlighted::before {
    color: #FF912C;
  }

  .rmp-amp-stars, .rmp-amp-average, .rmp-amp-votes {
    display: inline-block;
  }

  /* Text-align center in rating widget */
  .rmp-amp-rating-widget {
    text-align: center;
  }

  /* Bottom margin on title */
  #rmp-amp-rating-widget-title {
    margin-bottom: 10px;
  }

  /* These two inputs should not be displayed */
  #rmp-amp-action, #rmp-amp-post-id {
    display: none;
  }

  /* Center the stars */
  .rmp-amp-centered-fieldset {
    margin-left: auto;
    margin-right: auto;
    max-width: 200px;
  }

  .rmp-amp-rating {
    --star-size: 3;  /* use CSS variables to calculate dependent dimensions later */
    padding: 0;  /* to prevent flicker when mousing over padding */
    border: none;  /* to prevent flicker when mousing over border */
    unicode-bidi: bidi-override; direction: rtl;  /* for CSS-only style change on hover */
    text-align: left;  /* revert the RTL direction */
    user-select: none;  /* disable mouse/touch selection */
    font-size: 3em;  /* fallback - IE doesn't support CSS variables */
    font-size: calc(var(--star-size) * 1em);  /* because <code>var(--star-size)em</code> would be too good to be true */
    cursor: pointer;
    /* disable touch feedback on cursor: pointer - http://stackoverflow.com/q/25704650/1269037 */
    -webkit-tap-highlight-color: rgba(0,0,0,0);
    -webkit-tap-highlight-color: transparent;
    margin-bottom: 16px;
  }
  /* the stars */
  .rmp-amp-rating > label {
    display: inline-block;
    position: relative;
    width: 1.1em;  /* magic number to overlap the radio buttons on top of the stars */
    width: calc(var(--star-size) / 3 * 1.1em);
  }
  .rmp-amp-rating > *:hover,
  .rmp-amp-rating > *:hover ~ label,
  .rmp-amp-rating:not(:hover) > input:checked ~ label {
    color: transparent;  /* reveal the contour/white star from the HTML markup */
    cursor: inherit;  /* avoid a cursor transition from arrow/pointer to text selection */
  }
  .rmp-amp-rating > *:hover:before,
  .rmp-amp-rating > *:hover ~ label:before,
  .rmp-amp-rating:not(:hover) > input:checked ~ label:before {
    content: "★";
    position: absolute;
    left: 0;
    color: gold;
  }
  .rmp-amp-rating > input {
    position: relative;
    transform: scale(3);  /* make the radio buttons big; they don't inherit font-size */
    transform: scale(var(--star-size));
    /* the magic numbers below correlate with the font-size */
    top: -0.5em;  /* margin-top doesn't work */
    top: calc(var(--star-size) / 6 * -1em);
    margin-left: -2.5em;  /* overlap the radio buttons exactly under the stars */
    margin-left: calc(var(--star-size) / 6 * -5em);
    z-index: 2;  /* bring the button above the stars so it captures touches/clicks */
    opacity: 0;  /* comment to see where the radio buttons are */
    font-size: initial; /* reset to default */
  }
  form.amp-form-submit-error [submit-error] {
    color: red;
  }
  <?php
}

You might have to adjust the css to fit your website.

Blaz