<div id="app">
  <form>
    <input type="range" min='10' value='50' max='80'  v-model="scoopedCornersSize" @input="change">
    <label for='r'>--r: <output for='r'>{{ scoopedCornersSize }}</output></label>
  </form>
  <scooped-corners :scooped-corners-size= scoopedCornersSize>
    <h3>The Amur Leopard</h3>
	
    <p>The Amur leopard has some very distinguishing features. The hairs of its summer pelt are 2.5 cm long, but in winter they are replaced by 7 cm long ones.</p>

    <p>Apart from its long winter coat, which is a light colour in the winter, and more reddish-yellow in the summer, the Amur leopard is easily told apart from other leopard subspecies by its widely spaced rosettes with thick borders. It also has longer legs, probably an adaptation for walking through snow.</p>
  </scooped-corners>
</div>

<template id="scooped-corners">
  <div class="scooped-corners" :style="{'--scoopedCornersSize': changeCornersSize}">
    <slot></slot>
  </div>
</template>
$theme-dark: #262626;
$theme-light: invert($theme-dark);
$theme-orange: #f90;
$theme-tomato: #b53;
$theme-purple: #95a;

:root { --scoopedCornersSize: 50px }

.scooped-corners { /* these are all the essential styles */
	overflow: hidden;
	position: relative;
	margin: .5em auto 0;
	padding: var(--scoopedCornersSize);
 	width: calc(100% - 2*var(--scoopedCornersSize) - 1em);
	max-width: 47em;
  min-height: 10em;
	border-radius: 1em;
	color: #fff;
	
	&:before {
    position: absolute;
		z-index: -1;
		top: 0; left: 0;
		margin: calc(-1 * var(--scoopedCornersSize));
    padding: inherit;
		border-radius: 50%;
		box-shadow: 0 0 0 85em rgba(#95a, .875);
    content: ''
  }
}

/* JUST PRETTYFYING STUFF, NOT ESSENTIAL FOR A WORKING DEMO */

//* slider variables */
$track-w: 90vw;
$track-h: .25em;
$thumb-d: 1.5em;

//* slider mixins */
@mixin track() {
	box-sizing: border-box;
	border: none;
	width: 100%; height: $track-h;
	border-radius: $track-h;
	background: $theme-light
}

@mixin thumb() {
	box-sizing: border-box;
	border: none;
	width: $thumb-d; height: $thumb-d;
	border-radius: 50%;
	background: currentcolor
}

* {
	margin: 0;
	color: inherit;
	font: inherit
}

html {
	$over-c: rgba($theme-light, .5);
	min-width: 10em; height: 100%;
	background: 
		linear-gradient($over-c, $over-c), 
		url(https://images.unsplash.com/photo-1510920018318-3b4dfe979e4d?ixlib=rb-0.3.5&q=80&fm=jpg&crop=entropy&cs=tinysrgb&w=1080&fit=max&ixid=eyJhcHBfaWQiOjE0NTg5fQ&s=76eda3022d9860f69a7fc7a94e46c3e6) 0 0/ cover;
	font: 1em/ 1.25 trebuchet ms, verdana, arial, sans-serif
}

h3 {
	font: 700 2em/ 1.5 kalam, cursive;
	text-align: center
}

p { padding: .75em 0 }

em {
	display: block;
	font-style: italic;
	text-align: right
}

a { color: lighten($theme-orange, 15%) }

form {
	padding: .75em;
	background: $theme-dark;
	color: $theme-light;
	font: 1em/ 2 consolas, monaco, monospace
}

[type='range'] {
	&, &::-webkit-slider-thumb {
		-webkit-appearance: none
	}
	
	display: block;
	margin: 0 auto 1em;
	padding: 0;
	width: $track-w; height: $thumb-d;
	background: transparent;
	cursor: pointer;
	
	&::-webkit-slider-runnable-track {
		@include track
	}
	&::-moz-range-track { @include track }
	&::-ms-track { @include track }
	
	&::-webkit-slider-thumb {
		margin-top: .5*($track-h - $thumb-d);
		@include thumb
	}
	&::-moz-range-thumb { @include thumb }
	&::-ms-thumb {
		margin-top: 0;
		@include thumb
	}
	
	&::-ms-tooltip { display: none }
	
	&:focus {
		outline: solid 1px transparent;
		color: $theme-orange;
		
		+ label output { color: $theme-orange }
	}
}

label { display: block }

output:after { content: 'px' }
View Compiled
Vue.component('scooped-corners',{
  template: '#scooped-corners',
  props: ['scoopedCornersSize'],
  computed: {
    changeCornersSize: function () {
      return this.scoopedCornersSize + 'px'
    }
  }
})

let app = new Vue({
  el: '#app',
  data () {
    return {
      scoopedCornersSize: '50'
    }
  },
  methods: {
    change: function (e) {
      this.scoopedCornersSize = e.target.value
      console.log(this.scoopedCornersSize)
    }
  }
})
View Compiled

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

  1. https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.13/vue.min.js