JSFiddle - React, Tailwind, and code Playground

HTML

<form class="choose-game" action="?" method="get">
				<fieldset>
					<select name="game" id="game" required>
						<option value="battlefield 4">Battlefield 4</option>
						<option value="call of duty ghosts">Call Of Duty: Ghosts</option>
						<option value="fifa 2014">FIFA 2014</option>
						<option value="league of legends">League of Legends</option>
						<option value="need for speed rivals">Need For Speed: Rivals</option>
					</select>
					<input type="submit" value="Wybierz">
				</fieldset>
			</form>

CSS

* { margin: 0; padding: 0; -moz-box-sizing: border-box; -webkit-box-sizing: border-box; box-sizing: border-box; }
fieldset { border: 0; }
.choose-game select, .choose-game input[type="submit"] { border: 5px solid #3498db; padding: 10px; font: 18px Arial, Verdana, sans-serif; transition: border-color, background-color .3s, .3s; }
.choose-game select {  }
.choose-game input[type="submit"] { background-color: #3498db; color: #fff; cursor: pointer; }