Solarized theme for Slack (including background - not just sidebar)

slack-solarized-theme.css

#msgs_scroller_div::-webkit-scrollbar-track, #client_body::before, .client_container, 
#search_terms, #client_body, #footer, ts-message, .channel_header, ts-jumper ts-jumper-container,
ts-jumper input[type="text"] {
  background: #002B36 !important;
}

#client_body::before {
  border-bottom: 1px solid #268BD2 !important;
}

ts-message, .channel_title .channel_name, ts-jumper input[type="text"],
ts-jumper ol li .member_real_name, ts-jumper ol li .view_name, ts-jumper ol li .channel_name { 
  color: #93A1A1 !important;
}

.light_theme ts-message .message_content .message_sender, #msg_input::-webkit-input-placeholder,
ts-jumper input[type="text"]::-webkit-input-placeholder {
  color: #93A1A1 !important;
}

#msg_input, #primary_file_button {
  background: transparent !important;
  color: #93A1A1 !important;
  border-color: #073642 !important;
}

.day_divider .day_divider_label {
  color: #93A1A1 !important;
}

.day_container .day_msgs {
  border-top: 1px solid #268BD2 !important;
}

ts-message:hover, .day_divider .day_divider_label {
  background: #268BD2 !important;
}

#messages_container::after {
  background: none !important;
}

.bot_label { 
  padding: 0 4px !important;
  border-radius: 3px !important;
  background: #073642 !important;
}

From braden: After launching slack by doing

export SLACK_DEVELOPER_MENU=true
open -a /Applications/Slack.app

Open an inspector for your team, then paste this into the console..unfortunately i haven't found a good way to automate this yet.

const cssURI = 'https://gist.githubusercontent.com/anziem/806da8b104ae360d53bd46d5e5c90c4f/raw/adde403b6417568a59a5a73578a7565fe04458a3/slack-solarized-theme.css';

fetch(cssURI)
  .then(response => { 
    return response.text()  
  })
  .then(css => {
    let style = document.createElement('style')
    style.innerHTML = css

    document.body.appendChild(style)
  })

in a inspector in order to apply the theme to the team.