我试图仅在椭圆的左侧应用白色边框，并将其他边保持为透明。但是，边框未应用于左侧的整个部分。需要进行哪些更改才能显示预期的输出？
#ellipsis {
background-color: #3ebede;
height: 25px;
color: #000;
position: relative;
padding: 4px 15px 4px 30px;
width: 200px;
border-radius: 20px;
margin: -4px -25px -4px -4px;
text-align: left;
display: inline-block;
border: solid;
border-color: transparent transparent transparent white
}<body>
<button id="ellipsis"></button>
<button id="ellipsis"></button>
<button id="ellipsis"></button>
</body>考虑box-shadow：
.ellipsis {
background-color: #3ebede;
height: 25px;
color: #000;
position: relative;
padding: 4px 15px 4px 30px;
width: 200px;
border-radius: 20px;
margin: -4px -25px -4px -4px;
text-align: left;
display: inline-block;
box-shadow:-2px 0 0 2px #fff;
border:none;
}<body>
<button class="ellipsis"></button>
<button class="ellipsis"></button>
<button class="ellipsis"></button>
</body>如果你想要透明度，这里有一个radial-gradient的技巧：
.ellipsis {
background-color: #3ebede;
height: 25px;
color: #000;
position: relative;
padding: 4px 15px 4px 30px;
width: 200px;
border-radius: 20px;
margin: -4px -25px -4px -4px;
text-align: left;
display: inline-block;
border:none;
}
.ellipsis:not(:last-child) {
background:radial-gradient(4px 3px at right,transparent 30px,#3ebede 31px);
}
body {
background:#ddd;
}<div>
<button class="ellipsis"></button>
<button class="ellipsis"></button>
<button class="ellipsis"></button>
</div>