Widen freeform foreground/background entry fields

also tweaks the left/right padding, so the format indicator doesn't overlap.
this new size should accommodate rgba with 3 digit r, g, b values and an alpha with 2 decimals.

Closes #65

src/views/css/main.css

@@ -71,7 +71,7 @@ section#background-color .buttons {
 section#foreground-color .container,
 section#background-color .container {
  position: relative;
- width: 18rem;
+ width: 24rem;
  margin: auto;
  display: flex;
  justify-content: center;
@@ -84,7 +84,7 @@ section#background-color input.free-value {
  appearance: none;
  -webkit-appearance: none;
  border: 1px #cccccc dashed;
- padding: 0.2rem 2.5rem;
+ padding: 0.2rem 4.5rem;
  background: transparent;
  text-align: center;
  font-size: 1.4rem;