CSS elimina el botón de contorno azul
button {
outline: none;
}
Helpful Hamerkop
button {
outline: none;
}div {
border-bottom-color: coral;
}<style>
.tweet-button {
background-color: rgb(81, 131, 211);
color:white;
border:none;
height: 36px;
width: 75;
font-weight: bold;
border-radius:18px;
margin-right: 8px;
cursor: pointer;
}
<style>