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Pure CSS Alert Bar

by Jennifer Perrin

HTML

<div id="alert">
    <a class="alert" href="#alert">This is a slide down alert!</a>
</div>

CSS

body { padding: 0; }

/* Alert */
#alert { position: relative; }
#alert:hover:after {
    background: hsla(0,0%,0%,.8);
    border-radius: 3px;
    color: #f6f6f6;
    content: 'Click to dismiss';
    font: bold 12px/30px sans-serif;
    height: 30px;
    left: 50%;
    margin-left: -60px;
    position: absolute;
    text-align: center;
    top: 50px;
    width: 120px;
}
#alert:hover:before {
    border-bottom: 10px solid hsla(0,0%,0%,.8);
    border-left: 10px solid transparent;
    border-right: 10px solid transparent;
    content: '';
    height: 0;
    left: 50%;
    margin-left: -10px;
    position: absolute;
    top: 40px;
    width: 0;
}
#alert:target {
    display: none;
}
.alert {
    background-color: #c4453c;
    background-image: -webkit-linear-gradient(135deg, transparent,
                      transparent 25%, hsla(0,0%,0%,.05) 25%,
                      hsla(0,0%,0%,.05) 50%, transparent 50%,
                      transparent 75%, hsla(0,0%,0%,.05) 75%,
                      hsla(0,0%,0%,.05));
    background-image: -moz-linear-gradient(135deg, transparent,
                      transparent 25%, hsla(0,0%,0%,.1) 25%,
                      hsla(0,0%,0%,.1) 50%, transparent 50%,
                      transparent 75%, hsla(0,0%,0%,.1) 75%,
                      hsla(0,0%,0%,.1));
    background-image: -ms-linear-gradient(135deg, transparent,
                      transparent 25%, hsla(0,0%,0%,.1) 25%,
                      hsla(0,0%,0%,.1) 50%, transparent 50%,
                      transparent 75%, hsla(0,0%,0%,.1) 75%,
                      hsla(0,0%,0%,.1));
    background-image: -o-linear-gradient(135deg, transparent,
                      transparent 25%, hsla(0,0%,0%,.1) 25%,
                      hsla(0,0%,0%,.1) 50%, transparent 50%,
                      transparent 75%, hsla(0,0%,0%,.1) 75%,
                      hsla(0,0%,0%,.1));
    background-image: linear-gradient(135deg, transparent,
                      transparent 25%,...

JavaScript

// Click run to start animation again.