Superhuman style overrides

Superhuman styles.css

/********************************************************************************
SUPERHUMAN STYLE OVERRIDES
I love Superhuman but I also love my eyes. This Stylish/Stylus stylesheet--

- Adds higher zoom, font sizes, and contrast to message list and thread views
- For Windows, replaces ugly scrollbars with nicer ones

Add this style to "mail.superhuman.com".

By Brandon Wang (twitter/@bradr github/@bw)
No rights reserved (CC0)
********************************************************************************/

/*********************************
Windows/Chrome improvements
*********************************/

/*
Style scrollbars on Windows so they don't look hideous and native.
Windows-- make better scrollbars!
*/

.Platform-windows *::-webkit-scrollbar {
    width: 5px;
    height: 5px;
    background-color: transparent;
}

.Platform-windows *::-webkit-scrollbar-thumb {
    background-color: rgba(0,0,0,0.1);
    border-radius: 2px;
}

/*********************************
Zoom things in
*********************************/

/*
Prevent squinting by zooming thread lists, sidebars, and search.
Superhuman is great but why is everything so damn small...
*/

.ThreadListView > .ThreadList {
    zoom: 125%;
}

.LabelSwitcher {
    zoom: 120%;
    width: 20vw;
}

.ContactPane {
    zoom: 120%;
}

.SearchBars {
    zoom: 120%;
}

.NotificationsStack {
    zoom: 120%;
}

/*
We can't zoom the thread views because the floating text formatting toolbars
will not be positioned correctly. So we manually adjust the font size on most
of the elements in the thread.
*/
.ThreadPane-header {
    zoom: 110%;
}

.MessagePane-expanded {
    padding-top: 15px;
}

.MessagePane-from,
.MessagePane-snippet,
.RecipientList,
.From,
.DropdownSelector-button,
.ComposeForm-subject {
    font-size: 16px !important;
}

.ComposeForm-actionPane {
    zoom: 120%;
}

/* Inside the Superhuman sandbox */
html > body > div > div.frame-content * {
    font-size: 16px !important;
    line-height: 26px !important;
}

/*********************************
Add contrast
*********************************/

/*
Darken recipients + subject lines so they have higher contrast.
*/

.ThreadListItem-subject {
    color: rgba(0,0,0,0.95);
}

/*********************************
Add breathing room
*********************************/

/*
Add more breathing room to thread panes by increasing hard-coded max width.
This also offsets the reduced line widths caused by zooming everything in.
*/

.ThreadPane-container {
    flex-basis: calc(900px + 8rem);
}

.ThreadPane-header,
.ThreadPane-messages {
    max-width: calc(900px + 8rem);
}

/*
Content pane paragraphs are slightly too tight re: line spacing.
*/

.ContactPane-bio,
.timeline-Tweet-text {
    /* Need to include !important here because they're already overriding things */
    line-height: 150% !important; 
}

Hi! How can I "add" this to mail.superhuman.com (I am coder and I hacked some css myself but i don't know how to deploy for a specific website)

stylebot for chrome based browsers worked for me: https://chrome.google.com/webstore/detail/stylebot/oiaejidbmkiecgbjeifoejpgmdaleoha?hl=en