How to make border inside triangle? - html

Question

i am making block with arrow and border looks like
And i have tried this.
* {
box-sizing: border-box;
}
.block-arr {
background: purple;
margin: 20px;
margin-right: 100px;
position: relative;
}
.block-arr .inner {
min-height: 100px;
display: flex;
padding: 20px;
align-items: center;
position: relative;
}
.block-arr .inner:after {
border-top: 50px solid transparent;
border-bottom: 50px solid transparent;
border-left: 50px solid purple;
content: '';
position: absolute;
left: 100%;
top: 0;
}
.block-arr:after {
border-top: 50px solid transparent;
border-bottom: 50px solid transparent;
border-left: 50px solid purple;
content: '';
position: absolute;
left: 100%;
top: 0;
}
<div class="block-arr">
<div class="inner">
<strong>Main Heading</strong>
<span>Sub Heading</span>
</div>
</div>
How can i make block like image? And can we make this arrow height responsive?

Answer 1

I would consider a mix of skew transformation, inset box-shadow and some linear-gradient:
* {
box-sizing: border-box;
}
.block-arr {
padding: 50px;
margin: 20px;
margin-right: 100px;
position: relative;
background: linear-gradient(#fff, #fff)2px 0/2px 100% no-repeat, purple;
border-left: 2px solid purple;
z-index: 0;
}
.block-arr:before {
content: "";
position: absolute;
top: 0;
bottom: 50%;
left: 0;
right: 0;
background: purple;
border: 5px solid purple;
border-bottom: none;
border-left: none;
box-shadow: -2px 2px 0px #fff inset;
transform: skew(25deg);
transform-origin: top left;
z-index: -1;
}
.block-arr:after {
content: "";
position: absolute;
top: 50%;
bottom: 0;
left: 0;
right: 0;
background: purple;
border: 5px solid purple;
border-top: none;
border-left: none;
box-shadow: -2px -2px 0px #fff inset;
transform: skew(-25deg);
transform-origin: bottom left;
z-index: -1;
}
<div class="block-arr">
<strong>Main Heading</strong>
<span>Sub Heading</span>
</div>
<div class="block-arr">
<strong>Main Heading</strong><br/>
<span>Sub Heading</span>
</div>
<div class="block-arr">
</div>
And here is a more compressed version with some CSS variable to easily handle color. You can also do the same to handle others variables:
* {
box-sizing: border-box;
}
.block-arr {
--c1:purple;
--c2:#fff;
padding: 50px;
margin: 20px;
margin-right: 100px;
position: relative;
background: linear-gradient(var(--c2), var(--c2))2px 0/2px 100% no-repeat, var(--c1);
border-left: 2px solid var(--c1);
z-index: 0;
}
.block-arr:before,
.block-arr:after {
left: 0;
right: 0;
content: "";
position: absolute;
background: var(--c1);
border: 5px solid var(--c1);
border-left: none;
z-index: -1;
}
.block-arr:before {
top: 0;
bottom: 50%;
border-bottom: none;
box-shadow: -2px 2px 0px var(--c2) inset;
transform: skew(25deg);
transform-origin: top left;
}
.block-arr:after {
top: 50%;
bottom: 0;
border-top: none;
box-shadow: -2px -2px 0px var(--c2) inset;
transform: skew(-25deg);
transform-origin: bottom left;
}
<div class="block-arr">
</div>
<div class="block-arr" style="--c1:red;--c2:yellow">
<strong>Main Heading</strong>
<span>Sub Heading</span>
<p>And yes it is reponsive and grow when height grow</p>
</div>
BONUS
Another fancy and more complex way with only linear-gradient:
* {
box-sizing: border-box;
}
.block-arr {
--c1:purple;
--c2:#fff;
padding: 50px;
margin: 20px;
margin-right: 100px;
position: relative;
border:1px solid;
background:
linear-gradient(to top left,transparent calc(50% + 4px),var(--c2) calc(50% + 4px),var(--c2) calc(50% + 6px),transparent 0) 100% 100%/50px 50% no-repeat,
linear-gradient(to bottom left,transparent calc(50% + 4px),var(--c2) calc(50% + 4px),var(--c2) calc(50% + 6px),transparent 0) 100% 0/50px 50% no-repeat,
linear-gradient(var(--c2),var(--c2)) 4px calc(100% - 4px)/calc(100% - 58px) 2px no-repeat,
linear-gradient(var(--c2),var(--c2)) 4px 4px/calc(100% - 58px) 2px no-repeat,
linear-gradient(var(--c2),var(--c2)) 4px 4px/2px calc(100% - 8px) no-repeat,
linear-gradient(to top left ,transparent 50%,var(--c1) 50%) 100% 100%/50px 50% no-repeat,
linear-gradient(to bottom left,transparent 50%,var(--c1) 50%) 100% 0/50px 50% no-repeat,
linear-gradient(var(--c1),var(--c1)) 0 0/calc(100% - 50px) 100% no-repeat;
}
<div class="block-arr">
</div>

Answer 2

Using :after and :before pseudo elements, i have made this design.
Hope it fulfills your requirement.
Thanks
CSS and HTML:
* {
box-sizing: border-box;
}
p { margin:0; }
.block-arr {
background: purple;
margin: 20px;
margin-right: 100px;
position: relative;
}
.block-arr .inner {
min-height: 100px;
/*display: flex;*/
padding: 20px;
align-items: center;
position: relative;
}
.block-arr .inner:after {
border-top: 50px solid transparent;
border-bottom: 50px solid transparent;
border-left: 50px solid purple;
content: '';
position: absolute;
left: 100%;
top: 0;
}
.block-arr:after {
border-top: 50px solid transparent;
border-bottom: 50px solid transparent;
border-left: 50px solid purple;
content: '';
position: absolute;
left: 100%;
top: 0;
}
.bordered { position:relative; border:1px solid #fff; border-right:none; display: flex; align-items: center; padding:20px; }
.bordered:before, .bordered:after {
content: "";
position: absolute;
height: 72%;
width: 1px;
background: #fff;
top: 0;
right: 0;
z-index: 4;
}
.bordered:before {
transform: rotate(45deg);
top: auto;
right: -3.3%;
bottom: -11%;
}
.bordered:after {
transform: rotate(-45deg);
top: -12%;
right: -3.3%;
}
<div class="block-arr">
<div class="inner"><div class="bordered">
<p><strong>Main Heading</strong>
<span>Sub Heading</span></p>
</div></div>
</div>