How to achieve curved top pointer - html

Question

Can anyone please help with this? How to achieve the attached button with CSS only(no image)?
This is my code so far:
.triangle-up {
width: 0;
height: 0;
border-left: 25px solid transparent;
border-right: 25px solid transparent;
border-bottom: 50px solid #555;
}
<div class="triangle-up"></div>

Answer 1

Use pseudo element where you apply a radial-gradient:
.box {
margin:60px 10px 0;
display:inline-block;
color:#fff;
text-align:center;
padding:10px 30px;
background:green;
border-radius:50px;
position:relative;
}
.box:before {
content:"";
position:absolute;
bottom:100%;
left:50%;
width:60px;
height:25px;
transform:translateX(-50%);
background:
radial-gradient(farthest-side at top left , transparent 98%,green 100%) left,
radial-gradient(farthest-side at top right, transparent 98%,green 100%) right;
background-size:50.2% 100%;
background-repeat:no-repeat;
}
body {
background:pink;
}
<div class="box">text here</div>
<div class="box">more and more text here</div>
<div class="box">2 lines <br>of text</div>
Another idea in case you want any kind of coloration:
.box {
margin:60px 10px 0;
display:inline-block;
color:#fff;
text-align:center;
padding:10px 30px;
background-image:linear-gradient(60deg,yellow,purple,green,blue);
background-size:100% calc(100% + 25px);
background-position:bottom;
border-radius:50px;
position:relative;
z-index:0;
}
.box:before {
content:"";
position:absolute;
z-index:-1;
bottom:0;
left:0;
right:0;
height:calc(100% + 25px);
background-image:inherit;
-webkit-mask:
radial-gradient(farthest-side at top left , transparent 98%,#fff 100%) left,
radial-gradient(farthest-side at top right, transparent 98%,#fff 100%) right;
mask:
radial-gradient(farthest-side at top left , transparent 98%,#fff 100%) left,
radial-gradient(farthest-side at top right, transparent 98%,#fff 100%) right;
-webkit-mask-size:30px 25px;
mask-size:30px 25px;
-webkit-mask-position:calc(50% - 15px) 0,calc(50% + 15px) 0;
mask-position:calc(50% - 15px) 0,calc(50% + 15px) 0;
-webkit-mask-repeat:no-repeat;
mask-repeat:no-repeat;
}
body {
background:pink;
}
<div class="box">text here</div>
<div class="box" style="
background-image:linear-gradient(160deg,white,red,black,orange);">more and more text here</div>
<div class="box" style="
background-image:linear-gradient(180deg,blue 20%,violet 20%,black);">2 lines <br>of text</div>

Answer 2

you can use the shadow on both rounded pseudos
.bubble {
position: relative;
background: #00aabb;
border-radius: 0.4em;
width: 200px;
height: 100px;
}
.bubble:after,
.bubble:before {
content: "";
position: absolute;
height: 3em;
width: 3em;
border-radius: 50%;
top: 100%;
margin: -1px;
}
:after {
left: 50%;
box-shadow: -0.8em -1.4em 0 -0.5em #00aabb
}
:before {
right: 50%;
box-shadow: 0.8em -1.4em 0 -0.5em #00aabb;
}
<div class='bubble'></div>
to understand how it works, give a background to the pseudo and another color to the shadows. You'll be able to reproduce for the sides or the top. It's a matter of the circle size and shadow's size and direction.

Answer 3

One option is to create a normal rectangle and then position two circles over it, such that they create a curved point.
In the demo below, this rectangle is represented by the .point div, and the circles are represented by the pseudo-elements ::before and ::after.
.caption {
position: relative;
width: 350px;
margin-top: 40px;
}
.caption>.content {
width: 100%;
height: 100%;
padding: 10px;
box-sizing: border-box;
border-radius: 30px;
background-color: green;
color: white;
text-align: center;
}
.caption>.point {
position: absolute;
left: 50%;
top: -30px;
width: 30%;
height: 30px;
transform: translateX(-50%) translateZ(1px);
overflow: hidden;
background-color: green;
}
.caption>.point::before,
.caption>.point::after {
content: '';
display: block;
width: 100%;
height: 200%;
position: absolute;
top: 0;
left: 0;
border-radius: 100%;
background-color: white;
}
.caption>.point::before {
transform: translateX(-49%) translateY(-50%);
}
.caption>.point::after {
transform: translateX(49%) translateY(-50%);
}
<div class="caption">
<div class="point"></div>
<div class="content">This is some text!</div>
</div>
Here is a more visual demonstration of what the code is actually doing. The ::before and ::after elements are represented by the red circles. I've reduced the transparency of their fill to 50% so you can see which portion of the .point div they're cutting off.
.caption {
position: relative;
width: 350px;
margin-top: 40px;
}
.caption>.content {
width: 100%;
height: 100%;
padding: 10px;
box-sizing: border-box;
border-radius: 30px;
background-color: green;
color: white;
text-align: center;
}
.caption>.point {
position: absolute;
left: 50%;
top: -30px;
width: 30%;
height: 30px;
transform: translateX(-50%) translateZ(1px);
background-color: green;
}
.caption>.point::before,
.caption>.point::after {
content: '';
display: block;
width: 100%;
height: 200%;
position: absolute;
top: 0;
left: 0;
border-radius: 100%;
background-color: rgba(255,255,255,0.5);
border: 1px solid red;
}
.caption>.point::before {
transform: translateX(-49%) translateY(-50%);
}
.caption>.point::after {
transform: translateX(49%) translateY(-50%);
}
<div class="caption">
<div class="point"></div>
<div class="content">This is some text!</div>
</div>