amp-app-banner.css

amp-app-banner {
  position: fixed !important;
  bottom: 0 !important;
  left: 0;
  width: 100%;
  max-height: 100px !important;
  box-sizing: border-box;
  background: #fff;
  z-index: 13;
  box-shadow: 0 0 5px 0 rgba(0,0,0, 0.2) !important;
}

i-amphtml-app-banner-top-padding {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  background: #fff;
  height: 4px;
  /** Must be above the dismiss button to cover bottom shadow */
  z-index: 15;
}

.amp-app-banner-dismiss-button {
  position: absolute;
  width: 28px;
  height: 28px;
  top: -28px;
  right: 0;
  background-image: url('data:image/svg+xml;charset=utf-8,<svg width="13" height="13" viewBox="341 8 13 13" xmlns="http://www.w3.org/2000/svg"><path fill="#4F4F4F" d="M354 9.31L352.69 8l-5.19 5.19L342.31 8 341 9.31l5.19 5.19-5.19 5.19 1.31 1.31 5.19-5.19 5.19 5.19 1.31-1.31-5.19-5.19z" fill-rule="evenodd"/></svg>');
  background-size: 13px 13px;
  background-position: 9px center;
  background-color: #fff;
  background-repeat: no-repeat;
  z-index: 14;
  box-shadow: 0 -1px 1px 0 rgba(0,0,0, 0.2);
  border: none;
  border-radius: 12px 0 0 0;
}

/* Increase tapping area of the dismiss button */
.amp-app-banner-dismiss-button:before {
  position: absolute;
  content: '';
  top: -20px;
  right: 0;
  left: -20px;
  bottom: 0;
}

[dir=rtl] .amp-app-banner-dismiss-button {
  right: auto;
  left: 0;
  border-top-left-radius: 0;
  border-top-right-radius: 12px;
  background-position: 6px center;
}

[dir=rtl] .amp-app-banner-dismiss-button:before {
  right: -20px;
  left: 0;
}