zulip/static/styles/alerts.scss

$alert-red: hsl(16, 60%, 45%);
$alert-error-red: hsl(0, 80%, 40%);

.alert-display {
    display: none;

    &.show {
        display: block;
    }
}

.alert-animations {
    &.show {
        animation-name: fadeIn;
        animation-duration: 0.3s;
        animation-fill-mode: forwards;
    }

    &.fade-out {
        animation-name: fadeOut;
        animation-duration: 0.3s;
        animation-fill-mode: forwards;
    }

    .faded {
        opacity: 0.7;
    }
}

/* general alert styling changes */
.alert {
    @extend .alert-display;

    &#organization-status {
        margin: 20px;
    }

    &.stream_create_info {
        margin: 10px 10px 0px 10px;
    }
}

/* alert box component changes */
.alert-box {
    position: absolute;
    top: 0px;
    left: 0px;
    width: 900px;
    margin-left: calc(50% - 450px);
    z-index: 220;

    .alert {
        @extend .alert-animations;

        font-size: 1rem;
        border-radius: 4px;
        background-color: hsl(0, 0%, 100%);

        position: relative;

        /* gives room for the error icon. */
        padding-left: 50px;
        padding-top: 10px;
        padding-bottom: 10px;

        text-shadow: none;

        color: $alert-red;
        border: 1px solid $alert-red;
        box-shadow: 0 0 2px $alert-red;

        &::before {
            position: absolute;
            top: 10px;
            left: 12px;

            font-family: "FontAwesome";
            font-size: 1.3em;
            content: "\f071";

            color: hsl(16, 60%, 55%);
        }

        &.alert-error {
            color: $alert-error-red;
            border: 1px solid $alert-error-red;
            box-shadow: 0 0 2px $alert-error-red;

            &::before {
                color: $alert-error-red;
            }
        }

        .exit {
            position: absolute;
            top: 10px;
            right: 0px;

            font-size: 2.5em;
            font-weight: 300;

            cursor: pointer;

            &::after {
                padding: 10px;
                content: "\d7";
            }
        }
    }

    .browser-alert .error::before {
        content: "Browser Error: ";
        font-weight: 600;
    }
}

/* animation section */
@keyframes fadeIn {
    0% {
        display: block;
        opacity: 0;
        transform: translateY(-100px);
    }

    100% {
        opacity: 1;
        transform: translateY(0px);
    }
}

@keyframes fadeOut {
    0% {
        opacity: 1;
        transform: translateY(0px);
    }

    100% {
        display: none;
        opacity: 0;
        transform: translateY(-100px);
    }
}

/* @media queries */
@media (max-width: 900px) {
    .alert-box {
        width: 80%;
        left: 10%;
        margin-left: 0px;
    }
}