ui/accessibility/extensions/alt/hide-images.css

/* Copyright (c) 2014 The Chromium Authors. All rights reserved.
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file. */

body[show-alt] img {
    /* add some fake content to hang the ::before element off */
    content: "" !important;
    background-image: url('data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7')

    /* display non-floated and remove any background color */
    float: none !important;
    background-color: inherit !important;

    /* set height to contain the text content */
    height: 100% !important;
}

body[show-alt] img:not([alt]):not([aria-hidden=true]):not([role=presentation]):before {
    content: url('chrome-extension://__MSG_@@extension_id__/images/speech-missing-alt-16.png') " " attr(_repaired) !important;
    box-shadow: inset 0 -4px 0 rgba(230, 124, 115, 1) !important;
}

body[show-alt] img:not([aria-hidden=true]):not([role=presentation]):not([alt='']):before {
    content: url('chrome-extension://__MSG_@@extension_id__/images/speech-16.png') " " attr(alt) !important;
    box-shadow: inset 0 -4px 0 rgba(139, 195, 74, 1) !important;
    display: table;
    clear: both;
}

@keyframes slideDown {
    from {
      transform: translateY(-150%);
    }
    to {
      transform: translateY(0px);
    }
}

@keyframes slideUp {
    from {
      transform: translateY(0%);
    }
    to {
      transform: translateY(-150%);
    }
}

body[show-alt] .show-alt-infobar {
    animation-delay: 0.5s;
    animation-direction: forwards;
    animation-duration: 0.5s;
    animation-iteration-count: 1;
    animation-name: slideDown;
    animation-timing-function: ease;
    transform: translateY(0%);
}

body:not([show-alt]) .show-alt-infobar {
    animation-delay: 0.5s;
    animation-direction: forwards;
    animation-duration: 0.5s;
    animation-iteration-count: 1;
    animation-name: slideUp;
    animation-timing-function: ease;
    transform: translateY(-150%);
}

.show-alt-infobar {
    animation-fill-mode: backwards;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100000001;  /* :( */
    position: fixed !important;
    background: #fde073 !important;
    text-align: center !important;
    line-height: 2.0;
    overflow: hidden;
    box-shadow: 0 0 5px black;
    font-family: Arial, sans-serif !important;
    font-size: 12pt !important;
}

.show-alt-infobar .content {
    display: inline-block !important;
}

.show-alt-infobar span {
    margin: 5px;
}

.show-alt-infobar button.link-button {
    -webkit-appearance: none !important;
    font: inherit !important;
    background: inherit !important;
    border: none !important;
    color: #1155CC !important;
    cursor: pointer !important;
    display: inline !important;
    margin: 0 !important;
    padding: 0 !important;
    text-decoration: none !important;
    box-shadow: none !important;
    text-transform: none !important;
    padding: none !important;
}

.show-alt-infobar button.link-button:hover,
.show-alt-infobar button.link-button:focus {
    color: #1155CC;
    text-decoration: underline;
    outline: none;
}

.show-alt-infobar .controls {
    float: right !important;
    display: inline-block !important;
    padding-right: 5px !important;
}

.show-alt-infobar .close-button-gray:hover,
.show-alt-infobar .close-button-gray:focus {
    background-position: -143px -96px !important;
    outline: none;
}

.show-alt-infobar .close-button-gray {
    -webkit-appearance: none !important;
    font: inherit !important;
    background: inherit !important;
    border: none !important;
    cursor: pointer !important;
    margin: 0 !important;
    padding: 0 !important;
    text-decoration: none !important;
    box-shadow: none !important;
    text-transform: none !important;
    padding: none !important;
    width: 13px !important;
    height: 13px !important;
    background-position: -175px -96px !important;
    background-image: url('chrome-extension://__MSG_@@extension_id__/images/statusbarButtonGlyphs.png') !important;
    background-size: 320px 144px !important;
    display: inline-block !important;
}