gtk2/gtk/gtk-default.css

@define-color fg_color #000;
@define-color bg_color #dcdad5;
@define-color text_color #000;
@define-color base_color #fff;
@define-color selected_bg_color #4b6983;
@define-color selected_fg_color #fff;
@define-color tooltip_bg_color #eee1b3;
@define-color tooltip_fg_color #000;
@define-color placeholder_text_color #808080;

@define-color info_fg_color rgb (181, 171, 156);
@define-color info_bg_color rgb (252, 252, 189);
@define-color warning_fg_color rgb (173, 120, 41);
@define-color warning_bg_color rgb (250, 173, 61);
@define-color question_fg_color rgb (97, 122, 214);
@define-color question_bg_color rgb (138, 173, 212);
@define-color error_fg_color rgb (166, 38, 38);
@define-color error_bg_color rgb (237, 54, 54);

@define-color success_bg_color #4e9a06;

* {
  color: @fg_color;
  border-color: shade (@bg_color, 0.6);
  padding: 2px;
}

GtkWindow, .button, .slider {
  background-color: @bg_color;
}

.expander, GtkTreeView.view.expander {
  color: #fff;
}

.expander:hover,
GtkTreeView.view.expander:selected:hover {
  color: @text_color;
}

*:insensitive {
  border-color: shade (@bg_color, 0.7);
  background-color: shade (@bg_color, 0.9);
  color: shade (@bg_color, 0.7);
}

.entry:selected {
  background-color: shade (@bg_color, 0.9);
  color: @fg_color;
}

.entry:selected:focused {
  background-color: @selected_bg_color;
  color: @selected_fg_color;
}

.view {
  border-width: 0;
  border-radius: 0;
  background-color: @base_color;
  color: @text_color;
}
.view:selected {
  background-color: shade (@bg_color, 0.9);
  color: @fg_color;
}

.view:selected:focused {
  background-color: @selected_bg_color;
  color: @selected_fg_color;
}

.view column:sorted row,
.view column:sorted row:hover {
  background-color: shade (@bg_color, 0.85);
}

.view column:sorted row:nth-child(odd),
.view column:sorted row:nth-child(odd):hover {
  background-color: shade (@bg_color, 0.8);
}

.view row,
.view row:hover {
  background-color: @base_color;
  color: @text_color;
}

.view row:nth-child(odd),
.view row:nth-child(odd):hover {
  background-color: shade (@base_color, 0.93);
}

.view row:selected:focused {
  background-color: @selected_bg_color;
}

.view row:selected {
  background-color: darker (@bg_color);
  color: @selected_fg_color;
}

.view.cell.trough,
.view.cell.trough:hover,
.view.cell.trough:selected,
.view.cell.trough:selected:focused {
  background-color: @bg_color;
  color: @fg_color;
}

.view.cell.progressbar,
.view.cell.progressbar:hover,
.view.cell.progressbar:selected,
.view.cell.progressbar:selected:focused {
  background-color: @selected_bg_color;
  color: @selected_fg_color;
}

.rubberband {
  background-color: alpha (@fg_color, 0.25);
  border-color: @fg_color;
  border-style: solid;
  border-width: 1px;
}

.tooltip,
.tooltip * {
  background-color: @tooltip_bg_color;
  color: @tooltip_fg_color;
  border-color: @tooltip_fg_color;
  border-width: 1px;
  border-style: solid;
}

.button,
.slider {
  border-style: outset;
  border-width: 2px;
}

.button:active {
  background-color: shade (@bg_color, 0.7);
  border-style: inset;
}

.spinbutton.button:hover,
.button:hover,
.slider:hover {
  background-color: @selected_bg_color;
  color: @selected_fg_color;
  border-color: shade (@selected_bg_color, 0.7);
}

.trough {
  background-color: darker (@bg_color);
  border-style: inset;
  border-width: 1px;
  padding: 0;
}

.entry {
  border-style: inset;
  border-width: 2px;
  background-color: @base_color;
  color: @text_color;
}

.entry:insensitive {
  background-color: shade (@base_color, 0.9);
  color: shade (@base_color, 0.7);
}
.entry:active {
  background-color: #c4c2bd;
  color: #000;
}

.progressbar,
.entry.progressbar,
.cell.progressbar {
  background-color: @selected_bg_color;
  border-color: shade (@selected_bg_color, 0.7);
  color: @selected_fg_color;
  border-style: outset;
  border-width: 1px;
}

.level-bar.indicator-discrete {
    margin: 1px;
}

.level-bar.fill-block {
    background-color: @selected_bg_color;
}

.level-bar.fill-block.level-low {
    background-color: @warning_bg_color;
}

.level-bar.fill-block.level-high {
    background-color: @success_bg_color;
}

.level-bar.fill-block.empty-fill-block {
    background-color: @base_color;
}

GtkCheckButton:hover,
GtkCheckButton:selected,
GtkRadioButton:hover,
GtkRadioButton:selected {
  background-color: shade (@bg_color, 1.05);
}

.check, .radio,
.cell.check, .cell.radio,
.cell.check:hover, .cell.radio:hover {
  border-style: solid;
  border-width: 1px;
  background-color: @base_color;
  border-color: @fg_color;
}

.check:active, .radio:active,
.check:hover, .radio:hover {
  background-color: @base_color;
  border-color: @fg_color;
  color: @text_color;
}

.check:selected, .radio:selected {
  background-color: darker (@bg_color);
  color: @selected_fg_color;
  border-color: @selected_fg_color;
}

.check:selected:focused, .radio:selected:focused {
  background-color: @selected_bg_color;
}

.menuitem.check, .menuitem.radio {
  color: @fg_color;
  border-style: none;
  border-width: 0;
}

.popup {
  border-style: outset;
  border-width: 1px;
}

.viewport {
  border-style: inset;
  border-width: 2px;
}

.notebook {
  border-style: outset;
  border-width: 1px;
}

.frame {
  border-style: inset;
  border-width: 1px;
}

GtkScrolledWindow.frame {
  padding: 0;
}

.menu,
.menubar,
.toolbar {
  border-style: outset;
  border-width: 1px;
}

.menu:hover,
.menubar:hover,
.menuitem:hover,
.menuitem.check:hover,
.menuitem.radio:hover {
  background-color: @selected_bg_color;
  color: @selected_fg_color;
}

GtkSpinButton.button {
  border-width: 1px;
}

.scale.slider:hover,
GtkSpinButton.button:hover {
  background-color: shade (@bg_color, 1.05);
  border-color: shade (@bg_color, 0.8);
}

GtkSwitch.trough:active {
  background-color: @selected_bg_color;
  color: @selected_fg_color;
}

GtkToggleButton.button:inconsistent {
  border-style: outset;
  border-width: 1px;
  background-color: shade (@bg_color, 0.9);
  border-color: shade (@bg_color, 0.7);
}

GtkLabel:selected {
  background-color: shade (@bg_color, 0.9);
}

GtkLabel:selected:focused {
  background-color: @selected_bg_color;
}

.info {
  background-color: @info_bg_color;
  color: @info_fg_color;
}

.warning {
  background-color: @warning_bg_color;
  color: @warning_fg_color;
}

.question {
  background-color: @question_bg_color;
  color: @question_fg_color;
}

.error {
  background-color: @error_bg_color;
  color: @error_fg_color;
}

.highlight {
  background-color: @selected_bg_color;
  color: @selected_fg_color;
}

.light-area-focus {
  color: #000;
}

.dark-area-focus {
  color: #fff;
}
GtkCalendar.view {
  border-width: 1px;
  border-style: inset;
  padding: 1px;
}

GtkCalendar.view:inconsistent {
  color: darker (@bg_color);
}

GtkCalendar.header {
  background-color: @bg_color;
  border-style: outset;
  border-width: 2px;
}

GtkCalendar.highlight {
  border-width: 0;
}

GtkCalendar.button {
  background-color: @bg_color;
}

GtkCalendar.button:hover {
  background-color: lighter (@bg_color);
  color: @fg_color;
}

.menu * {
  border-width: 0;
  padding: 2px;
}

@keyframes spinner {
  0% { background-position: 50.00% 0.00%, 89.09% 18.83%, 98.75% 61.13%, 71.69% 95.05%, 28.31% 95.05%, 1.25% 61.13%, 10.91% 18.83%; }
  3.125% { background-position: 59.75% 0.96%, 94.42% 27.05%, 95.64% 70.42%, 62.49% 98.42%, 19.93% 89.95%, 0.02% 51.40%, 17.74% 11.80%; }
  6.25% { background-position: 69.13% 3.81%, 98.05% 36.16%, 90.78% 78.93%, 52.80% 99.92%, 12.72% 83.32%, 0.71% 41.62%, 25.81% 6.24%; }
  9.375% { background-position: 77.78% 8.43%, 99.82% 45.80%, 84.35% 86.33%, 43.01% 99.51%, 6.93% 75.40%, 3.29% 32.17%, 34.82% 2.36%; }
  12.5% { background-position: 85.36% 14.64%, 99.69% 55.60%, 76.60% 92.34%, 33.49% 97.19%, 2.81% 66.51%, 7.66% 23.40%, 44.40% 0.31%; }
  15.625% { background-position: 91.57% 22.22%, 97.64% 65.18%, 67.83% 96.71%, 24.60% 93.07%, 0.49% 56.99%, 13.67% 15.65%, 54.20% 0.18%; }
  18.75% { background-position: 96.19% 30.87%, 93.76% 74.19%, 58.38% 99.29%, 16.68% 87.28%, 0.08% 47.20%, 21.07% 9.22%, 63.84% 1.95%; }
  21.875% { background-position: 99.04% 40.25%, 88.20% 82.26%, 48.60% 99.98%, 10.05% 80.07%, 1.58% 37.51%, 29.58% 4.36%, 72.95% 5.58%; }
  25% { background-position: 100.00% 50.00%, 81.17% 89.09%, 38.87% 98.75%, 4.95% 71.69%, 4.95% 28.31%, 38.87% 1.25%, 81.17% 10.91%; }
  28.125% { background-position: 99.04% 59.75%, 72.95% 94.42%, 29.58% 95.64%, 1.58% 62.49%, 10.05% 19.93%, 48.60% 0.02%, 88.20% 17.74%; }
  31.25% { background-position: 96.19% 69.13%, 63.84% 98.05%, 21.07% 90.78%, 0.08% 52.80%, 16.68% 12.72%, 58.38% 0.71%, 93.76% 25.81%; }
  34.375% { background-position: 91.57% 77.78%, 54.20% 99.82%, 13.67% 84.35%, 0.49% 43.01%, 24.60% 6.93%, 67.83% 3.29%, 97.64% 34.82%; }
  37.5% { background-position: 85.36% 85.36%, 44.40% 99.69%, 7.66% 76.60%, 2.81% 33.49%, 33.49% 2.81%, 76.60% 7.66%, 99.69% 44.40%; }
  40.625% { background-position: 77.78% 91.57%, 34.82% 97.64%, 3.29% 67.83%, 6.93% 24.60%, 43.01% 0.49%, 84.35% 13.67%, 99.82% 54.20%; }
  43.75% { background-position: 69.13% 96.19%, 25.81% 93.76%, 0.71% 58.38%, 12.72% 16.68%, 52.80% 0.08%, 90.78% 21.07%, 98.05% 63.84%; }
  46.875% { background-position: 59.75% 99.04%, 17.74% 88.20%, 0.02% 48.60%, 19.93% 10.05%, 62.49% 1.58%, 95.64% 29.58%, 94.42% 72.95%; }
  50% { background-position: 50.00% 100.00%, 10.91% 81.17%, 1.25% 38.87%, 28.31% 4.95%, 71.69% 4.95%, 98.75% 38.87%, 89.09% 81.17%; }
  53.125% { background-position: 40.25% 99.04%, 5.58% 72.95%, 4.36% 29.58%, 37.51% 1.58%, 80.07% 10.05%, 99.98% 48.60%, 82.26% 88.20%; }
  56.25% { background-position: 30.87% 96.19%, 1.95% 63.84%, 9.22% 21.07%, 47.20% 0.08%, 87.28% 16.68%, 99.29% 58.38%, 74.19% 93.76%; }
  59.375% { background-position: 22.22% 91.57%, 0.18% 54.20%, 15.65% 13.67%, 56.99% 0.49%, 93.07% 24.60%, 96.71% 67.83%, 65.18% 97.64%; }
  62.5% { background-position: 14.64% 85.36%, 0.31% 44.40%, 23.40% 7.66%, 66.51% 2.81%, 97.19% 33.49%, 92.34% 76.60%, 55.60% 99.69%; }
  65.625% { background-position: 8.43% 77.78%, 2.36% 34.82%, 32.17% 3.29%, 75.40% 6.93%, 99.51% 43.01%, 86.33% 84.35%, 45.80% 99.82%; }
  68.75% { background-position: 3.81% 69.13%, 6.24% 25.81%, 41.62% 0.71%, 83.32% 12.72%, 99.92% 52.80%, 78.93% 90.78%, 36.16% 98.05%; }
  71.875% { background-position: 0.96% 59.75%, 11.80% 17.74%, 51.40% 0.02%, 89.95% 19.93%, 98.42% 62.49%, 70.42% 95.64%, 27.05% 94.42%; }
  75% { background-position: 0.00% 50.00%, 18.83% 10.91%, 61.13% 1.25%, 95.05% 28.31%, 95.05% 71.69%, 61.13% 98.75%, 18.83% 89.09%; }
  78.125% { background-position: 0.96% 40.25%, 27.05% 5.58%, 70.42% 4.36%, 98.42% 37.51%, 89.95% 80.07%, 51.40% 99.98%, 11.80% 82.26%; }
  81.25% { background-position: 3.81% 30.87%, 36.16% 1.95%, 78.93% 9.22%, 99.92% 47.20%, 83.32% 87.28%, 41.62% 99.29%, 6.24% 74.19%; }
  84.375% { background-position: 8.43% 22.22%, 45.80% 0.18%, 86.33% 15.65%, 99.51% 56.99%, 75.40% 93.07%, 32.17% 96.71%, 2.36% 65.18%; }
  87.5% { background-position: 14.64% 14.64%, 55.60% 0.31%, 92.34% 23.40%, 97.19% 66.51%, 66.51% 97.19%, 23.40% 92.34%, 0.31% 55.60%; }
  90.625% { background-position: 22.22% 8.43%, 65.18% 2.36%, 96.71% 32.17%, 93.07% 75.40%, 56.99% 99.51%, 15.65% 86.33%, 0.18% 45.80%; }
  93.75% { background-position: 30.87% 3.81%, 74.19% 6.24%, 99.29% 41.62%, 87.28% 83.32%, 47.20% 99.92%, 9.22% 78.93%, 1.95% 36.16%; }
  96.875% { background-position: 40.25% 0.96%, 82.26% 11.80%, 99.98% 51.40%, 80.07% 89.95%, 37.51% 98.42%, 4.36% 70.42%, 5.58% 27.05%; }
  100% { background-position: 50.00% 0.00%, 89.09% 18.83%, 98.75% 61.13%, 71.69% 95.05%, 28.31% 95.05%, 1.25% 61.13%, 10.91% 18.83%; }
}

.spinner {
  background-color: transparent;
  background-image: -gtk-gradient(radial, center center, 0, center center, 0.5, to(currentColor), to(transparent)),
                    -gtk-gradient(radial, center center, 0, center center, 0.5, to(currentColor), to(transparent)),
                    -gtk-gradient(radial, center center, 0, center center, 0.5, to(currentColor), to(transparent)),
                    -gtk-gradient(radial, center center, 0, center center, 0.5, to(currentColor), to(transparent)),
                    -gtk-gradient(radial, center center, 0, center center, 0.5, to(currentColor), to(transparent)),
                    -gtk-gradient(radial, center center, 0, center center, 0.5, to(currentColor), to(transparent)),
                    -gtk-gradient(radial, center center, 0, center center, 0.5, to(currentColor), to(transparent));
  background-position: 50.00% 0.00%, 89.09% 18.83%, 98.75% 61.13%, 71.69% 95.05%, 28.31% 95.05%, 1.25% 61.13%, 10.91% 18.83%;
  background-size: 20% 20%;
  background-repeat: no-repeat;
  transition: background 500ms ease-out;
  animation: spinner 1s infinite linear;
  animation-play-state: paused;
}

.spinner:active {
  background-image: -gtk-gradient(radial, center center, 0, center center, 0.5, to(currentColor), to(transparent)),
                    -gtk-gradient(radial, center center, 0, center center, 0.5, to(alpha(currentColor,0.5)), to(transparent)),
                    -gtk-gradient(radial, center center, 0, center center, 0.5, to(alpha(currentColor,0.5833)), to(transparent)),
                    -gtk-gradient(radial, center center, 0, center center, 0.5, to(alpha(currentColor,0.6667)), to(transparent)),
                    -gtk-gradient(radial, center center, 0, center center, 0.5, to(alpha(currentColor,0.75)), to(transparent)),
                    -gtk-gradient(radial, center center, 0, center center, 0.5, to(alpha(currentColor,0.8333)), to(transparent)),
                    -gtk-gradient(radial, center center, 0, center center, 0.5, to(alpha(currentColor,0.9167)), to(transparent));
  background-size: 25% 25%, 10% 10%, 12.5% 12.5%, 15% 15%, 17.5% 17.5%, 20% 20%, 22.5% 22.5%;
  animation-play-state: running;
  transition: background 500ms ease-out;
}