November 7th, 2022
Let's make these lovely blur and gradient borders with Tailwind.
Final code
 1 <div class="my-20 grid grid-cols-3 text-center gap-12 px-6 text-black"> 2  <div class="relative"> 3    <div class="border border-gray-400 rounded-md bg-white p-16 relative z-20">1</div> 4    <div class="absolute inset-0 rounded-md translate-x-2 -translate-y-2 bg-gradient-to-br from-pink-500 via-cyan-500 to-violet-500 z-10"></div> 5  </div> 6  <div class="relative"> 7    <div class="border border-gray-400 rounded-md bg-white p-16 relative z-20">1</div> 8    <div class="absolute -inset-1 rounded-md bg-gradient-to-br from-pink-500 via-cyan-500 to-violet-500 z-10"></div> 9  </div>10  <div class="relative">11    <div class="border border-gray-400 rounded-md bg-white p-16 relative z-20">1</div>12    <div class="absolute -inset-1 rounded-md blur-md bg-gradient-to-br from-pink-500 via-cyan-500 to-violet-500 z-10"></div>13  </div>14</div>Let's make a grid first with grid grid-cols-3 gap-12, place it on the center horizontally with mx-auto and set max width of the grid  with max-w-xl.
1<div class="max-w-xl mx-auto">2  <div class="my-20 grid grid-cols-3 text-center gap-12 px-6 text-black ">3    <div class="p-16">1</div>4    <div class="p-16">1</div>5    <div class="p-16">1</div>6  </div>7</div>place another div inside of first grid element, position it behind with position absolute inset-0 -z-10 and apply background gradient.
 1<div class="max-w-xl mx-auto"> 2  <div class="my-20 grid grid-cols-3 text-center gap-12 px-6 text-black"> 3    <div class="relative">  4      <div class="border border-gray-400 rounded-md p-16 relative z-20">1</div> 5      <div class="absolute inset-0 z-10 bg-gradient-to-br from-pink-500 via-cyan-500 to-violet-500 rounded-md"></div> 6    </div> 7    <div class="">1</div> 8    <div class="">1</div> 9  </div>10</div> 
    
  move div with bg gradient to the right and above with translate-x-2 -translate-y-2
 1<div class="max-w-xl mx-auto"> 2  <div class="my-20 grid grid-cols-3 text-center gap-12 px-6 text-black"> 3    <div class="relative">  4      <div class="border border-gray-400 rounded-md p-16 relative z-20">1</div> 5      <div class="absolute inset-0 z-10 translate-x-2 -translate-y-2  bg-gradient-to-br from-pink-500 via-cyan-500 to-violet-500 rounded-md"></div> 6    </div> 7    <div class="">1</div> 8    <div class="">1</div> 9  </div>10</div> 
    
  add bg-white to the div in front (currently there is no background set, so it is transparent and you see background color of an element behind it)
 1<div class="max-w-xl mx-auto"> 2  <div class="my-20 grid grid-cols-3 text-center gap-12 px-6 text-black"> 3    <div class="relative">  4      <div class="border border-gray-400 rounded-md bg-white p-16 relative z-20">1</div> 5      <div class="absolute inset-0 z-10 translate-x-2 -translate-y-2  bg-gradient-to-br from-pink-500 via-cyan-500 to-violet-500 rounded-md"></div> 6    </div> 7    <div class="">1</div> 8    <div class="">1</div> 9  </div>10</div> 
    
   1<div class="my-20 grid grid-cols-3 text-center gap-12 px-6 text-black"> 2  <div class="relative"> 3    <div class="border border-gray-400 rounded-md bg-white p-16 relative z-20">1</div> 4    <div class="absolute inset-0 rounded-md translate-x-2 -translate-y-2 bg-gradient-to-br from-pink-500 via-cyan-500 to-violet-500 z-10"></div> 5  </div> 6  <div class="relative">  7    <div class="border border-gray-400 rounded-md bg-white p-16 relative z-20">1</div> 8    <div class="absolute -inset-1 rounded-md bg-gradient-to-br from-pink-500 via-cyan-500 to-violet-500 z-10"></div> 9  </div>10</div> 
    
   1<div class="my-20 grid grid-cols-3 text-center gap-12 px-6 text-black"> 2  <div class="relative"> 3    <div class="border border-gray-400 rounded-md bg-white p-16 relative z-20">1</div> 4    <div class="absolute inset-0 rounded-md translate-x-2 -translate-y-2 bg-gradient-to-br from-pink-500 via-cyan-500 to-violet-500 z-10"></div> 5  </div> 6  <div class="relative"> 7    <div class="border border-gray-400 rounded-md bg-white p-16 relative z-20">1</div> 8    <div class="absolute -inset-1 rounded-md bg-gradient-to-br from-pink-500 via-cyan-500 to-violet-500 z-10"></div> 9  </div>10  <div class="relative"> 11    <div class="border border-gray-400 rounded-md bg-white p-16 relative z-20">1</div>12    <div class="absolute -inset-1 rounded-md blur-md bg-gradient-to-br from-pink-500 via-cyan-500 to-violet-500 z-10"></div>13  </div>14</div>