amp-twitter.css

/**
 * Copyright 2018 The AMP HTML Authors. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS-IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

amp-twitter {
  transition-property: height;
  transition-duration: 250ms;
}

/**
 * [placeholder] is need for specificity over the base placeholder rules
 */
.i-amphtml-twitter-placeholder[placeholder] {
  display: flex;
  align-items: center;
  justify-content: center;
  max-width: 500px;
  min-width: 220px;
  margin: 0 auto;
  border-radius: 5px;
  border: 1px solid #e1e8ed;
  overflow: hidden;
  pointer-events: none;
}

/**
 * Need a separate element for this so that we can have the pulse animation
 * as well as the start/end transitions.
 */
.i-amphtml-twitter-placeholder-logo {
  width: 100%;
  height: 100%;
  max-width: 200px;
  max-height: 200px;
}

.i-amphtml-twitter-pulse .i-amphtml-twitter-placeholder-logo {
  animation: amp-twitter-pulse 750ms infinite alternate-reverse ease-in-out;
}

.i-amphtml-twitter-placeholder-svg {
  width: 100%;
  height: 100%;
}

.i-amphtml-twitter-pulse:not([i-amphtml-loading]) .i-amphtml-twitter-placeholder-svg  {
  transition-property: transform, opacity;
  transition-duration: 100ms;
  transition-timing-function: ease-in;
  /*
   * The initial state. Rather than start straight from the fullsize pulsing
   * state, we start off a bit smaller so there is some sense of progress.
   */
  transform: scale(0.4);
  opacity: 0.6;
}

.i-amphtml-twitter-fade .i-amphtml-twitter-placeholder-svg {
  transition-property: opacity;
  transition-duration: 100ms;
}

.i-amphtml-twitter-iframe {
  opacity: 0;
}

.i-amphtml-twitter-fade .i-amphtml-twitter-iframe,
.i-amphtml-twitter-pulse .i-amphtml-twitter-iframe  {
  transition-property: opacity;
  transition-duration: 200ms;
  transition-timing-function: ease-in;
}

.i-amphtml-twitter-pulse[i-amphtml-loading="start"] .i-amphtml-twitter-placeholder-svg {
  transition-duration: 250ms;
  transform: scale(1);
  opacity: 1;
}

amp-twitter[i-amphtml-loading="done"] .i-amphtml-twitter-placeholder {
  border: none;
}

amp-twitter[i-amphtml-loading="done"] .i-amphtml-twitter-placeholder-svg {
  opacity: 0;
}

.i-amphtml-twitter-burst[i-amphtml-loading="done"] .i-amphtml-twitter-placeholder-svg  {
  transition-duration: 250ms;
  transition-timing-function: ease-out;
  transform: scale(12);
}

.i-amphtml-twitter-fade[i-amphtml-loading="done"] .i-amphtml-twitter-placeholder-svg  {
  transition-duration: 250ms;
  transition-timing-function: ease-out;
}

amp-twitter[i-amphtml-loading="done"] .i-amphtml-twitter-iframe {
  opacity: 1;
}

@keyframes amp-twitter-pulse {
  0% {
    transform: scale(0.85);
    opacity: 0.9;
  }
  100% {
    transform: scale(1);
    opacity: 1;
  }
}