index.css

body {
  font: 16px Consolas
}
/*
Copied from persus project
*/
.math-input-buttons.absolute {
  left: -2px;
  position: absolute;
  top: 50px;
  z-index: 101;
}
.tex-button {
  display: block;
  float: left;
  width: 42px;
  height: 42px;
  margin: 2px;
  border: 1px solid #1c758a;
  background-color: white;
  border-radius: 5px;
}
.tex-button:hover {
  cursor: pointer;
  background-color: #f0f0f0;
}
.tex-button:focus {
  border: 2px solid #1c758a;
outline: none;
}
.tex-button-row {
margin: 5px 0;
}
.tex-button-row:first-child {
margin-top: 0;
}
.tex-button-row:last-child {
margin-bottom: 0;
}
/*
end of styles copied from perseus
*/


.math-buttons-current-panel {
    margin-top: 10px;
    width: 475px;
    float: left;
}
.fm-button-light {
  border: 2px solid transparent;
  display: inline-block;
  margin: 2px;
  padding: 0px 8px 0px 8px;
  background-color: white;
  font-size: 12px;
  font-weight: 600;
  color: #212121;
  border-radius: 15px;
}

.fm-button-light:hover {
  cursor: pointer;
  background-color: #f2f2f2;
}
.fm-button-light:focus {
  border: 2px solid #ffa535;
  outline: none;
}

.fm-button-light:disabled {
  background-color: #eaeaea;
}

.fm-button-grey {
  border: 2px solid transparent;
  padding: 4px 8px;
  margin: 4px;
  background-color: gray;
  color: #f1f1f1;
  border-radius: 15px;
  font-size: 12px;
  font-weight: 600;
}

.fm-button-grey:disabled {
  background-color: #eaeaea;
  color: #212121;
}

a.fm-button-grey:hover
{
  cursor: pointer;
  background-color: #3b3b3b;
  color: #f1f1f1;
}

.fm-button-grey:hover:enabled
{
  cursor: pointer;
  background-color: #3b3b3b;
}

.fm-button-grey:focus {
  border: 2px solid #ffa535;
  outline:0;
}

.fm-button-grey:active {
  transform: scale(0.99);
}

.fm-button-with-icon {
    height: 58px;
    width: 52px
}

.fm-button-icon {
    margin-top: 3px;
    height: 30px
}

.fm-button {
  border: 2px solid transparent;
  padding: 4px 6px;
  margin: 4px;
  background-color: #0d57bf;
  color: #f1f1f1;
  border-radius: 15px;
  font-size: 12px;
  font-weight: 600;
}

.fm-button:disabled {
  background-color: #eaeaea;
  color: #212121;
}

.fm-button-green:hover:enabled
{
  cursor: pointer;
  background-color: #052d66;
}


a.fm-button:hover
{
  cursor: pointer;
  background-color: #052d66;
  color: #f1f1f1;
}

.fm-button:hover:enabled
{
  cursor: pointer;
  background-color: #052d66;
}

.fm-button:focus {
  border: 2px solid #ffa535;
  outline:0;
}

.fm-button:active {
  transform: scale(0.99);
}

.fm-button-green {
    background-color: #008000
}

.fm-button-green:hover:enabled
{
  cursor: pointer;
  background-color: #005000
}

.fm-button-left {
  border: 2px solid transparent;
  padding: 4px 4px 4px 8px;
  margin-left: 1px;
  margin-right: 0px;
  color: #111111;
  border-top-left-radius: 15px;
  border-bottom-left-radius: 15px;
  border-top-right-radius: 0px;
  border-bottom-right-radius: 0px;
  font-size: 12px;
  font-weight: 600;
}

.fm-button-left:focus {
  border-left: 2px solid #ffa535;
  border-top: 2px solid #ffa535;
  border-top: 2px solid #ffa535;
  outline:0;
}

.fm-button-right {
  border: 2px solid transparent;
  padding: 4px 8px 4px 4px;
  margin-right: 1px;
  margin-left: 0px;
  color: #111111;
  border-top-right-radius: 15px;
  border-bottom-right-radius: 15px;
  border-top-left-radius: 0px;
  border-bottom-left-radius: 0px;
  font-size: 12px;
  font-weight: 600;
}

.fm-tab {
  background-color: #e1e1e1
}

.fm-tab:hover:enabled {
  background-color: #919191
}

.fm-tab-selected {
  background-color: #b1b1b1
}


.fm-button-selected {
  background-color: #052d66
}

.fm-button-selected:hover {
  background-color: #011024
}

.fm-close-button {
  border: 2px solid transparent;
  float: right;
  display: inline-block;
  height: 20px;
  margin: 2px;
  padding: 3px 6px 20px 6px;
  background-color: white;
  border: 1px solid #d1d1d1;
  color: #414141;
  border-radius: 3px;
}
.fm-close-button:hover {
  cursor: pointer;
  background-color: #e0e0e0;
}
.fm-close-button:focus {
  border: 2px solid #ffa535;
  outline: none;
}

.wide-tex-button {
    width:90px
}

@media (max-width: 640px) {
    .math-input-buttons {
        background-color: rgba(245, 245, 245, 0.9);
        border-radius: 5px;
        border: 1px solid #ddd;
        box-sizing: border-box;
        margin-top: 5px;
        padding: 10px;
        width: 601px;
    }
    .matrix-end-caps-and-buttons {
        max-width: 100px
    }

    .math-buttons-current-panel {
        width: 400px;
    }
    .math-input-buttons.absolute {
      left: -60px;
      right: -200px;
      position: absolute;
      top: -3px;
      z-index: 101;
    }
}

@media (min-width: 641px) {
    .math-input-buttons {
        background-color: rgba(245, 245, 245, 0.9);
        border-radius: 5px;
        border: 1px solid #ddd;
        box-sizing: border-box;
        margin-top: 5px;
        padding: 10px;
        width: 641px;
    }
}

/* https://www.w3schools.com/howto/howto_js_snackbar.asp */
.snackbar {
  width: 250px;
  margin-left: -125px;
  background-color: #333;
  color: #fff;
  text-align: center;
  font: 18px Verdana;
  padding: 16px;
  position: fixed;
  z-index: 1;
  left: 50%;
  bottom: 0;
}