Coloured tabs for TST

color-tabs.css

@namespace url(http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul);

/* override base tab color */
:root:root {
  --color-100: white;
}

/* Plain */
.tabbrowser-tab {
  --color-main: var(--color-100);
  --color-text: black;
  --color-highlight: var(--color-800);
}

/* Pinned */
.tabbrowser-tab[pinned="true"] {
  --color-main: var(--color-400);
}

/* Selected */
.tabbrowser-tab[visuallyselected="true"] {
  --color-main: var(--color-800);
  --color-text: white;
}

/* Hover */
.tabbrowser-tab:not([visuallyselected="true"]):not([pinned]):hover {
  --color-main: var(--color-600);
  --color-text: white;
}

/* Pinned Hover */
.tabbrowser-tab:not([visuallyselected="true"])[pinned]:not([titlechanged]):hover {
  --color-main: var(--color-600);
  --color-text: white;
}

.tabbrowser-tabs[treestyletab-style~="color"]:not([treestyletab-tabbar-position="top"])
  tab.tabbrowser-tab.tabbrowser-tab.tabbrowser-tab.tabbrowser-tab.tabbrowser-tab {
  background-color: var(--color-main) !important;
  color: var(--color-text) !important;
  border-width: 0px !important;
  min-height: 32px !important;
  -moz-border-bottom-colors: none !important;
  -moz-border-top-colors: none !important;
  -moz-border-left-colors: none !important;
  -moz-border-right-colors: none !important;
  border-left-width: 2px !important;
  border-left-color: var(--color-highlight) !important;
}

.tab-icon-image {
  box-shadow: 0px 0px 3px white !important;
  background-color: white !important;
  min-height: 20px !important;
  min-width: 20px !important;
  padding: 2px !important;
}

.tabbrowser-tabs:not([treestyletab-tabbar-position="top"])
  tab.tabbrowser-tab.tabbrowser-tab.tabbrowser-tab.tabbrowser-tab.tabbrowser-tab[pinned="true"] {
  min-height: 36px !important;
  min-width: 36px !important;
  padding: 4px !important;
  border-color: var(--color-highlight) !important;
  border-top-width: 2px !important;
  border-left-width: 0px !important;
  border-right-width: 0px !important;
}

.tabbrowser-tabs[treestyletab-mode="vertical"]
  .tabbrowser-tab.tabbrowser-tab.tabbrowser-tab.tabbrowser-tab[titlechanged][pinned]:not([visuallyselected="true"]) {
  background-image: none !important;
}

@keyframes blinker {  
  0% { opacity: 0.8; border-radius: 4px; }
  20% { opacity: inherit; border-radius: inherit; }
  80% { opacity: inherit; border-radius: inherit; }
  100% { opacity: 0.8; border-radius: 4px; }
}

.tabbrowser-tabs[treestyletab-mode="vertical"]
  .tabbrowser-tab.tabbrowser-tab.tabbrowser-tab.tabbrowser-tab[titlechanged]:not([pinned]):not([visuallyselected="true"]) {
  box-shadow: 124px 0px 100px -80px var(--color-highlight) inset !important;
}


.tabbrowser-tabs[treestyletab-mode="vertical"]
  .tabbrowser-tab.tabbrowser-tab.tabbrowser-tab.tabbrowser-tab[titlechanged]:not([visuallyselected="true"]) .tab-icon-image {
  animation: blinker 3s linear infinite;
}

.tabbrowser-tabs[treestyletab-mode="vertical"]
  .tabbrowser-tab.tabbrowser-tab.tabbrowser-tab.tabbrowser-tab[pinned][titlechanged]:not([visuallyselected="true"]) .tab-icon-image {
  box-shadow: 0px 0px 16px 8px white !important;
}

.tabbrowser-tabs[treestyletab-mode="vertical"]
  .tabbrowser-tab.tabbrowser-tab.tabbrowser-tab.tabbrowser-tab[pinned][titlechanged]:not([visuallyselected="true"]):hover {
  background-color: white !important;
  color: black !important;
  transition: all 0.2s ease;
}

/* Pending tabs */

.tabbrowser-tab.tabbrowser-tab.tabbrowser-tab.tabbrowser-tab.tabbrowser-tab.tabbrowser-tab.tabbrowser-tab.tabbrowser-tab[pending] {
  font-style: italic;
}

.tabbrowser-tab.tabbrowser-tab.tabbrowser-tab.tabbrowser-tab.tabbrowser-tab.tabbrowser-tab.tabbrowser-tab.tabbrowser-tab[pending]:not(:hover) {
  background-color: #eceff1 !important;
}

.tabbrowser-tab.tabbrowser-tab.tabbrowser-tab.tabbrowser-tab.tabbrowser-tab.tabbrowser-tab.tabbrowser-tab.tabbrowser-tab[pending]:not(:hover) .tab-icon-image {
  background: none !important;
  box-shadow: none !important;
  filter: grayscale(100%);
}

/* Begin themes */

[image*="mail"], [theme="red"] {
  --color-50: #ffebee;
  --color-100: #ffcdd2;
  --color-200: #ef9a9a;
  --color-300: #e57373;
  --color-400: #ef5350;
  --color-500: #f44336;
  --color-600: #e53935;
  --color-700: #d32f2f;
  --color-800: #c62828;
  --color-900: #b71c1c;
  --color-a100: #ff8a80;
  --color-a200: #ff5252;
  --color-a400: #ff1744;
  --color-a700: #d50000;
}

[theme="pink"] {
  --color-50: #fce4ec;
  --color-100: #f8bbd0;
  --color-200: #f48fb1;
  --color-300: #f06292;
  --color-400: #ec407a;
  --color-500: #e91e63;
  --color-600: #d81b60;
  --color-700: #c2185b;
  --color-800: #ad1457;
  --color-900: #880e4f;
  --color-a100: #ff80ab;
  --color-a200: #ff4081;
  --color-a400: #f50057;
  --color-a700: #c51162;
}

[theme="purple"] {
  --color-50: #f3e5f5;
  --color-100: #e1bee7;
  --color-200: #ce93d8;
  --color-300: #ba68c8;
  --color-400: #ab47bc;
  --color-500: #9c27b0;
  --color-600: #8e24aa;
  --color-700: #7b1fa2;
  --color-800: #6a1b9a;
  --color-900: #4a148c;
  --color-a100: #ea80fc;
  --color-a200: #e040fb;
  --color-a400: #d500f9;
  --color-a700: #aa00ff;
}

[theme="deep purple"] {
  --color-50: #ede7f6;
  --color-100: #d1c4e9;
  --color-200: #b39ddb;
  --color-300: #9575cd;
  --color-400: #7e57c2;
  --color-500: #673ab7;
  --color-600: #5e35b1;
  --color-700: #512da8;
  --color-800: #4527a0;
  --color-900: #311b92;
  --color-a100: #b388ff;
  --color-a200: #7c4dff;
  --color-a400: #651fff;
  --color-a700: #6200ea;
}

[image*="facebook"], [theme="indigo"] {
  --color-50: #e8eaf6;
  --color-100: #c5cae9;
  --color-200: #9fa8da;
  --color-300: #7986cb;
  --color-400: #5c6bc0;
  --color-500: #3f51b5;
  --color-600: #3949ab;
  --color-700: #303f9f;
  --color-800: #283593;
  --color-900: #1a237e;
  --color-a100: #8c9eff;
  --color-a200: #536dfe;
  --color-a400: #3d5afe;
  --color-a700: #304ffe;
}

[image*="calendar"], [theme="blue"] {
  --color-50: #e3f2fd;
  --color-100: #bbdefb;
  --color-200: #90caf9;
  --color-300: #64b5f6;
  --color-400: #42a5f5;
  --color-500: #2196f3;
  --color-600: #1e88e5;
  --color-700: #1976d2;
  --color-800: #1565c0;
  --color-900: #0d47a1;
  --color-a100: #82b1ff;
  --color-a200: #448aff;
  --color-a400: #2979ff;
  --color-a700: #2962ff;
}

[image*="messenger"], [theme="light blue"] {
  --color-50: #e1f5fe;
  --color-100: #b3e5fc;
  --color-200: #81d4fa;
  --color-300: #4fc3f7;
  --color-400: #29b6f6;
  --color-500: #03a9f4;
  --color-600: #039be5;
  --color-700: #0288d1;
  --color-800: #0277bd;
  --color-900: #01579b;
  --color-a100: #80d8ff;
  --color-a200: #40c4ff;
  --color-a400: #00b0ff;
  --color-a700: #0091ea;
}

[image*="reddit"], [theme="cyan"] {
  --color-50: #e0f7fa;
  --color-100: #b2ebf2;
  --color-200: #80deea;
  --color-300: #4dd0e1;
  --color-400: #26c6da;
  --color-500: #00bcd4;
  --color-600: #00acc1;
  --color-700: #0097a7;
  --color-800: #00838f;
  --color-900: #006064;
  --color-a100: #84ffff;
  --color-a200: #18ffff;
  --color-a400: #00e5ff;
  --color-a700: #00b8d4;
}

[theme="teal"] {
  --color-50: #e0f2f1;
  --color-100: #b2dfdb;
  --color-200: #80cbc4;
  --color-300: #4db6ac;
  --color-400: #26a69a;
  --color-500: #009688;
  --color-600: #00897b;
  --color-700: #00796b;
  --color-800: #00695c;
  --color-900: #004d40;
  --color-a100: #a7ffeb;
  --color-a200: #64ffda;
  --color-a400: #1de9b6;
  --color-a700: #00bfa5;
}

[theme="green"] {
  --color-50: #e8f5e9;
  --color-100: #c8e6c9;
  --color-200: #a5d6a7;
  --color-300: #81c784;
  --color-400: #66bb6a;
  --color-500: #4caf50;
  --color-600: #43a047;
  --color-700: #388e3c;
  --color-800: #2e7d32;
  --color-900: #1b5e20;
  --color-a100: #b9f6ca;
  --color-a200: #69f0ae;
  --color-a400: #00e676;
  --color-a700: #00c853;
}

[image*="hangouts"], [theme="light green"] {
  --color-50: #f1f8e9;
  --color-100: #dcedc8;
  --color-200: #c5e1a5;
  --color-300: #aed581;
  --color-400: #9ccc65;
  --color-500: #8bc34a;
  --color-600: #7cb342;
  --color-700: #689f38;
  --color-800: #558b2f;
  --color-900: #33691e;
  --color-a100: #ccff90;
  --color-a200: #b2ff59;
  --color-a400: #76ff03;
  --color-a700: #64dd17;
}

[theme="lime"] {
  --color-50: #f9fbe7;
  --color-100: #f0f4c3;
  --color-200: #e6ee9c;
  --color-300: #dce775;
  --color-400: #d4e157;
  --color-500: #cddc39;
  --color-600: #c0ca33;
  --color-700: #afb42b;
  --color-800: #9e9d24;
  --color-900: #827717;
  --color-a100: #f4ff81;
  --color-a200: #eeff41;
  --color-a400: #c6ff00;
  --color-a700: #aeea00;
}

[theme="yellow"] {
  --color-50: #fffde7;
  --color-100: #fff9c4;
  --color-200: #fff59d;
  --color-300: #fff176;
  --color-400: #ffee58;
  --color-500: #ffeb3b;
  --color-600: #fdd835;
  --color-700: #fbc02d;
  --color-800: #f9a825;
  --color-900: #f57f17;
  --color-a100: #ffff8d;
  --color-a200: #ffff00;
  --color-a400: #ffea00;
  --color-a700: #ffd600;
}

[image*="music"], [theme="amber"] {
  --color-50: #fff8e1;
  --color-100: #ffecb3;
  --color-200: #ffe082;
  --color-300: #ffd54f;
  --color-400: #ffca28;
  --color-500: #ffc107;
  --color-600: #ffb300;
  --color-700: #ffa000;
  --color-800: #ff8f00;
  --color-900: #ff6f00;
  --color-a100: #ffe57f;
  --color-a200: #ffd740;
  --color-a400: #ffc400;
  --color-a700: #ffab00;
}

[theme="orange"] {
  --color-50: #fff3e0;
  --color-100: #ffe0b2;
  --color-200: #ffcc80;
  --color-300: #ffb74d;
  --color-400: #ffa726;
  --color-500: #ff9800;
  --color-600: #fb8c00;
  --color-700: #f57c00;
  --color-800: #ef6c00;
  --color-900: #e65100;
  --color-a100: #ffd180;
  --color-a200: #ffab40;
  --color-a400: #ff9100;
  --color-a700: #ff6d00;
}

[theme="deep orange"] {
  --color-50: #fbe9e7;
  --color-100: #ffccbc;
  --color-200: #ffab91;
  --color-300: #ff8a65;
  --color-400: #ff7043;
  --color-500: #ff5722;
  --color-600: #f4511e;
  --color-700: #e64a19;
  --color-800: #d84315;
  --color-900: #bf360c;
  --color-a100: #ff9e80;
  --color-a200: #ff6e40;
  --color-a400: #ff3d00;
  --color-a700: #dd2c00;
}

[theme="brown"] {
  --color-50: #efebe9;
  --color-100: #d7ccc8;
  --color-200: #bcaaa4;
  --color-300: #a1887f;
  --color-400: #8d6e63;
  --color-500: #795548;
  --color-600: #6d4c41;
  --color-700: #5d4037;
  --color-800: #4e342e;
  --color-900: #3e2723;
}

[theme="grey"] {
  --color-50: #fafafa;
  --color-100: #f5f5f5;
  --color-200: #eeeeee;
  --color-300: #e0e0e0;
  --color-400: #bdbdbd;
  --color-500: #9e9e9e;
  --color-600: #757575;
  --color-700: #616161;
  --color-800: #424242;
  --color-900: #212121;
}

[theme="inactive"] {
  --color-50: #fafafa;
  --color-100: #f5f5f5;
  --color-200: #f0f0f0;
  --color-300: #e5e5e5;
  --color-400: #e0e0e0;
  --color-500: #d5d5d5;
  --color-600: #d0d0d0;
  --color-700: #c5c5c5;
  --color-800: #c0c0c0;
  --color-900: #b5b5b5;
}

:root, [theme="blue grey"] {
  --color-50: #eceff1;
  --color-100: #cfd8dc;
  --color-200: #b0bec5;
  --color-300: #90a4ae;
  --color-400: #78909c;
  --color-500: #607d8b;
  --color-600: #546e7a;
  --color-700: #455a64;
  --color-800: #37474f;
  --color-900: #263238;
}

Thanks for the css rules!

TST provide API for other extensions, so instead of css file will be better to provide separate plugin extension for Tree Style Tabs with configurable rules of coloring.

For colorize tabs in Tree Style Tabs extension there are exists fork: https://github.com/meph1570/treestyletab that do this thing, but seems it is abandoned, and better way is provide separate extension, that use TST API instead of fork.

Can you convert your css rules to separate extension and apply this rules dynamically via TST API?