Source/devtools/front_end/popover.css

.popover {
    position: absolute;
    -webkit-border-image: url(Images/popoverBackground.png) 25 25 25 25;
    border-width: 25px;
    z-index: 100;
    pointer-events: none;

    transition: -webkit-transform 100ms ease-out, opacity 100ms ease-out;
    -webkit-transform: translateY(-20px);
    opacity: 0;
}

.popover .content {
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
    pointer-events: auto;
    overflow: auto;
    -webkit-user-select: text;
    line-height: 11px;
}

.popover .content.fixed-height {
    overflow: hidden;
}

.popover .arrow {
    position: absolute;
    background-image: url(Images/popoverArrows.png);
    width: 19px;
    height: 19px;
    margin-left: 15px;
    margin-top: -25px;
    top: 0;
    left: 0;
}

.popover.top-left-arrow .arrow {
    /* The default is top-left, no styles needed. */
}

.popover.top-right-arrow .arrow {
    right: 25px;
    left: auto;
}

.popover.bottom-left-arrow .arrow {
    top: auto;
    bottom: 0;
    margin-top: 0;
    margin-bottom: -25px;
    background-position: 0 -19px;
}

.popover.bottom-right-arrow .arrow {
    right: 15px;
    left: auto;
    top: auto;
    bottom: 0;
    margin-top: 0;
    margin-bottom: -25px;
    background-position: 0 -19px;
}

.popover.left-top-arrow .arrow {
    top: 0;
    margin-top: 15px;
    margin-left: -25px;
    background-position: 0 -38px;
}

.popover.left-bottom-arrow .arrow {
    top: auto;
    bottom: 0;
    margin-bottom: 15px;
    margin-left: -25px;
    background-position: 0 -38px;
}

.popover.right-top-arrow .arrow {
    right: 0;
    left: auto;
    top: 0;
    margin-top: 15px;
    margin-right: -25px;
    background-position: 0 -57px;
}

.popover.right-bottom-arrow .arrow {
    right: 0;
    left: auto;
    top: auto;
    bottom: 0;
    margin-bottom: 15px;
    margin-right: -25px;
    background-position: 0 -57px;
}

.popover-details {
    -webkit-user-select: text;
    vertical-align: top;
}

.popover-function-name {
    text-align: right;
}

.popover-stacktrace-title {
    padding-top: 4px;
}

.popover-details-row-title {
    font-weight: bold;
    text-align: right;
    white-space: nowrap;
}

.popover-details-row-data {
    white-space: nowrap;
}

.popover-details-title {
    border-bottom: 1px solid #B8B8B8;
    font-weight: bold;
    padding-bottom: 5px;
    padding-top: 0;
    white-space: nowrap;
}

.popover.fx-appear {
    opacity: 1;
    -webkit-transform: translateY(0px);
}