<select>
  <option selected value="0">Pure CSS Select</option>
  <option value="1">No Wrapper</option>
  <option value="2">No JS</option>
  <option value="3">Nice!</option>
</select>

:root {
  --arrow-bg: rgba(255, 255, 255, 0.3);
  --arrow-icon: url(https://upload.wikimedia.org/wikipedia/commons/9/9d/Caret_down_font_awesome_whitevariation.svg);
  --option-bg: white;
  --select-bg: rgba(255, 255, 255, 0.2);
}
* {
  box-sizing: border-box;
}
body {
  display: grid;
  place-items: center;
  min-height: 100vh;
  background: linear-gradient(35deg, red, purple);
}
/* <select> styles */
select {
  /* Reset */
  appearance: none;
  border: 0;
  outline: 0;
  font: inherit;
  /* Personalize */
  width: 20rem;
  padding: 1rem 4rem 1rem 1rem;
  background: var(--arrow-icon) no-repeat right 0.8em center / 1.4em,
    linear-gradient(to left, var(--arrow-bg) 3em, var(--select-bg) 3em);
  color: white;
  border-radius: 0.25em;
  box-shadow: 0 0 1em 0 rgba(0, 0, 0, 0.2);
  cursor: pointer;
  /* Remove IE arrow */
  &::-ms-expand {
    display: none;
  }
  /* Remove focus outline */
  &:focus {
    outline: none;
  }
  /* <option> colors */
  option {
    color: inherit;
    background-color: var(--option-bg);
  }
}

/*
  Pure CSS Select 2.0
  - No wrapper version
  - SVG icon
  - Glass style
*/