zulip/templates/zerver/emails/email.css

img {
    border: none;
    -ms-interpolation-mode: bicubic;
    max-width: 100%;
    vertical-align: bottom;
}

body {
    background: #f5f9f8;
    font-family: sans-serif;
    -webkit-font-smoothing: antialiased;
    font-size: 14px;
    line-height: 1.4;
    margin: 0;
    padding: 0;
    -ms-text-size-adjust: 100%;
    -webkit-text-size-adjust: 100%;
}

table {
    border-collapse: separate;
    mso-table-lspace: 0pt;
    mso-table-rspace: 0pt;
    width: 100%;
}

table td {
    font-family: sans-serif;
    font-size: 14px;
    vertical-align: top;
}

.body {
    background: #f5f9f8;
    width: 100%;
}

.container {
    display: block;
    margin: 0 auto !important;
    max-width: 500px;
    padding: 10px;
}

.content {
    box-sizing: border-box;
    display: block;
    margin: 20px auto 0 auto;
    max-width: 580px;
    padding: 10px;
}

.main {
    background: #fff;
    border-radius: 3px;
    width: 100%;
}

.wrapper {
    box-sizing: border-box;
    padding: 0px 20px 20px 20px;
}

.footer {
    clear: both;
    padding-top: 10px;
    text-align: center;
    width: 100%;
    margin-top: 20px;
}

.footer td,
.footer p,
.footer span,
.footer a {
    color: #999999;
    font-size: 12px;
    text-align: center;
}

.footer .content-block p {
    margin-top: 0px;
}

h1,
h2,
h3,
h4 {
    color: #000000;
    font-family: sans-serif;
    font-weight: 400;
    line-height: 1.4;
    margin: 0;
    margin-bottom: 30px;
}

h1 {
    font-size: 35px;
    font-weight: 300;
    text-align: center;
    text-transform: capitalize;
}

p,
ul,
ol {
    font-family: sans-serif;
    font-size: 14px;
    font-weight: normal;
    margin: 10px 0px;
}

p li,
ul li,
ol li {
    list-style-position: inside;
    margin-left: 5px;
}

a {
    color: #45a98e;
    text-decoration: underline;
}

a:hover {
    color: #51c6a6;
}

.important {
    border-bottom: 3px solid #d5e4e9;
}

.button {
    display: block;
    padding: 10px 0px;
    margin: 20px auto;
    width: 200px;
    border: 1px solid #7fd1ba;
    background: #7fd1ba;
    border-radius: 4px;
    font-size: 16px;
    outline: none;
    color: #ffffff;
    font-family: sans-serif;
    text-decoration: none;
    text-align: center;
    text-shadow: none;
}

a.button:hover {
    color: #ccf7eb;
    text-decoration: none;
}

.preheader {
    color: transparent;
    display: none;
    height: 0;
    max-height: 0;
    max-width: 0;
    opacity: 0;
    overflow: hidden;
    mso-hide: all;
    visibility: hidden;
    width: 0;
}

.illustration {
    pointer-events: none;
    cursor: default!important;
    z-index: 100;
}

@media only screen and (max-width: 620px) {
    table[class=body] h1 {
        font-size: 28px !important;
        margin-bottom: 10px !important;
    }

    table[class=body] p,
    table[class=body] ul,
    table[class=body] ol,
    table[class=body] td,
    table[class=body] span,
    table[class=body] a {
        font-size: 16px !important;
    }

    table[class=body] .wrapper {
        padding: 0px 10px 10px 10px;
    }

    table[class=body] .article {
        padding: 10px !important;
    }

    table[class=body] .content {
        padding: 0 !important;
    }

    table[class=body] .container {
        padding: 0 !important;
        width: 100% !important;
    }

    table[class=body] .main {
        border-left-width: 0 !important;
        border-radius: 0 !important;
        border-right-width: 0 !important;
    }

    table[class=body] .btn table {
        width: 100% !important;
    }

    table[class=body] .btn a {
        width: 100% !important;
    }

    table[class=body] .img-responsive {
        height: auto !important;
        max-width: 100% !important;
        width: auto !important;
    }
}

@media all {
    .ExternalClass {
        width: 100%;
    }

    .ExternalClass,
    .ExternalClass p,
    .ExternalClass span,
    .ExternalClass font,
    .ExternalClass td,
    .ExternalClass div {
        line-height: 100%;
    }

    /* iOS converts adreses in emails to links automatically*/
    .apple-link a {
        color: inherit !important;
        font-family: inherit !important;
        font-size: inherit !important;
        font-weight: inherit !important;
        line-height: inherit !important;
        text-decoration: none !important;
    }
}