fix(theme): searchbar should have normal size input (#2545)

Usually you want the searchbox to have the same font size (at least) as your body text. Otherwise it'll look awkardly small without other styling.

Also fixed a typo in `appearance`

before|after
---|---

meanwhile deduplicate

width is also already in normal style

src/css/theme/_search-box.scss

@@ -1,15 +1,13 @@
 .ais-search-box {
   display: inline-block;
   position: relative;
-  max-width: 300px;
-  width: 100%;
   height: 46px;
   white-space: nowrap;
-  box-sizing: border-box;
   font-size: 14px;
 
   &--input {
-    appearence: none;
+    appearance: none;
+    font: inherit;
     background: $white;
     display: inline-block;
     border: 1px solid #D4D8E3;