Twitch Dark Theme Restorer - Modifies the current Twitch.tv dark theme to resemble its older dark theme.

style.css

@-moz-document url-prefix("https://www.twitch.tv"), url-prefix("https://clips.twitch.tv") {
/*

  Twitch Dark Theme Restorer

  Homepage:   https://github.com/loopy750/Twitch-Dark-Theme-Restorer
    Twitch:   https://www.twitch.tv/loopy750

*/

/* ----------------- */
/* --- Site-wide --- */
/* ----------------- */
/* Main headers: Reduce font size */
h1,
.tw-font-size-2 {
    font-size: 3rem !important
}

/* Top navigation menu: Reduce font size */
.tw-font-size-4 {
    font-size: 1.65rem !important;
    font-weight: normal !important
}

/* Stream title & viewer count */
.tw-mg-r-1 .live-time,
.tw-animated-number.tw-animated-number--monospaced,
.tw-ellipsis.tw-font-size-5.tw-line-clamp-2.tw-strong.tw-word-break-word {
    font-size: 1.5rem !important;
    font-weight: normal !important
}

/* Semibold fonts: Transform to normal */
.tw-c-text-alt,
.tw-c-text-alt-2,
.tw-semibold {
    font-weight: normal !important
}

/* Live asset icon: Position */
.tw-svg__asset.tw-svg__asset--account.tw-svg__asset--live {
    margin-right: 1px !important
}

/* Buttons: Lighten/Darken (obsolete in new design) */
.chat-viewers__filter {
    filter: invert(12%) !important
}

/* Channel information bar: Adjust padding */
div.tw-block.tw-full-width .channel-banner.channel-banner--open {
    padding-bottom: 0.5rem !important
}

/* Channel information bar avatar: Adjust padding */
.tw-full-height.tw-full-width .tw-align-items-center .tw-align-items-center.tw-pd-x-1 {
    padding-top: 0.1rem !important
}

/* Channel status: Adjust margin */
div.side-nav-card__live-status.tw-flex-shrink-0.tw-mg-l-05,
div.tw-mg-l-05 .tw-c-text-alt.tw-font-size-6 {
    margin-top: 0.7rem !important;
    color: rgb(140, 150, 152) !important
}

/* Video player menu: Make transparent */
.simplebar-content .tw-c-background-base.tw-c-text-base,
.tw-absolute.tw-balloon .tw-border-radius-large.tw-c-background-base.tw-c-text-inherit.tw-elevation-3 {
    opacity: 0.9 !important
}
/*[[smooth-chat-scroll]]*/
/* ------------------- */
/* --- Light Theme --- */
/* ------------------- */
/* Buttons: Fix background colour */
.tw-root--hover .follow-btn__follow-btn-container,
.tw-root--hover .follow-btn__notification-toggle-container {
    filter: invert(10%) !important
}

/* Chat room: Darken background */
.tw-root--hover body,
.tw-root--hover .carousel-player-nav-arrow__container,
.tw-root--hover .chat-room,
.tw-root--hover .chat-room textarea.tw-block,
.tw-root--hover .tw-search-input {
    background-color: #F1F1EF !important
}

/* Browse: Darken background */
.tw-root--hover .directory-header-new__banner-cover {
    background: linear-gradient(0deg, #F1F1EF, rgba(255, 255, 255, .25)), linear-gradient(90deg, #E7E7E4, rgba(255, 255, 255, .25)) !important
}

/* Top navigation menu: Darken background */
.tw-root--hover .top-nav__menu.tw-c-background-base,
.tw-root--hover .top-nav__menu.tw-c-background-base .tw-avatar.tw-avatar--size-30 {
    background-color: #E7E7E4 !important
}

/* Side navigation menu: Darken background */
.tw-root--hover .side-nav__overlay-wrapper,
.tw-root--hover .side-nav {
    background-color: #E6E9E9 !important
}

/* Channel header, Channel information bar: Darken background */
.tw-root--hover .channel-header,
.tw-root--hover .channel-info-bar {
    background-color: #E7E7E4 !important;
    border-left: 1px ridge #DADED9 !important
}

/* Chat room header: Fix background colour */
.tw-root--hover .stream-chat-header,
.tw-root--hover .rooms-header.tw-align-items-center.tw-pd-r-1,
.tw-root--hover .channel-leaderboard-header-rotating.tw-block.tw-relative {
    background-color: #E7E7E4 !important
}

/* Users in chat list: Darken background */
.tw-root--hover div.chat-viewers__pane.tw-absolute.tw-bottom-0.tw-flex.tw-flex-column.tw-flex-nowrap {
    background-color: #F1F1EF !important
}

/* Sign up division: Darken background */
.tw-border-radius-large.tw-c-background-base.tw-elevation-1.tw-flex.tw-flex-column.tw-mg-1.tw-pd-2 {
    background-color: #F6F9F9 !important
}

/* ------------------ */
/* --- Dark Theme --- */
/* ------------------ */
/* Buttons: Fix background colour */
.tw-root--hover.tw-root--theme-dark .follow-btn__follow-btn-container,
.tw-root--hover.tw-root--theme-dark .follow-btn__notification-toggle-container {
    filter: invert(3%) !important
}

/* Chat room: Lighten background */
.tw-root--hover.tw-root--theme-dark body,
.tw-root--hover.tw-root--theme-dark .carousel-player-nav-arrow__container,
.tw-root--hover.tw-root--theme-dark .chat-room,
.tw-root--hover.tw-root--theme-dark .chat-room textarea.tw-block,
.tw-root--hover.tw-root--theme-dark .tw-search-input {
    background-color: #0F0E11 !important
}

/* Browse: Lighten background */
.tw-root--hover.tw-root--theme-dark .directory-header-new__banner-cover {
    background: linear-gradient(0deg, #0F0E11, rgba(0, 0, 0, .25)), linear-gradient(90deg, #37266D, rgba(0, 0, 0, .25)) !important
}
/*[[top-nav-purple]]*/
/* Side navigation menu: Lighten background */
.tw-root--hover.tw-root--theme-dark .side-nav__overlay-wrapper,
.tw-root--hover.tw-root--theme-dark .side-nav {
    background-color: #19171C !important
}

/* Channel header, Channel information bar: Lighten background */
.tw-root--hover.tw-root--theme-dark .channel-header,
.tw-root--hover.tw-root--theme-dark .channel-info-bar {
    background-color: #18181B !important;
    border-left: 1px ridge #252126 !important
}
/*[[channel-info-bar]]*/
/* Chat room header: Fix background colour */
.tw-root--hover.tw-root--hover.tw-root--theme-dark .stream-chat-header,
.tw-root--hover.tw-root--hover.tw-root--theme-dark .rooms-header.tw-align-items-center.tw-pd-r-1,
.tw-root--hover.tw-root--hover.tw-root--theme-dark .channel-leaderboard-header-rotating.tw-block.tw-relative {
    background-color: #18181B !important
}

/* Users in chat list: Lighten background */
.tw-root--hover.tw-root--theme-dark div.chat-viewers__pane.tw-absolute.tw-bottom-0.tw-flex.tw-flex-column.tw-flex-nowrap {
    background-color: #0F0E11 !important
}

/* Sign up division: Darken background */
.tw-root--hover.tw-root--theme-dark .tw-border-radius-large.tw-c-background-base.tw-elevation-1.tw-flex.tw-flex-column.tw-mg-1.tw-pd-2 {
    background-color: #151518 !important
}
}

Twitch Dark Theme Restorer

Modifies the current Twitch.tv dark theme to resemble its older dark theme.

Using the 'Stylus' or similar browser add-on, enter the code for URL www.twitch.tv, or for advanced Firefox users, userContent.css, for those who prefer to not use an add-on.