body {
   margin: 0;
   background: #e0e0e0;
   display: flex;
   flex-direction: column;
   align-items: center;
   justify-content: center;
   text-align:center;
   min-height: 100vh;
   font-family: "Montserrat", sans-serif;
   user-select: none;
}

#calculator {
   background: #232526;
   background: -webkit-linear-gradient(to right, #414345, #232526);
   background: linear-gradient(to right, #414345, #232526);
   width: 420px;
   height: 600px;
   border-radius: 20px;
   box-shadow: 5px 5px 10px #232526;
   display: flex;
   flex-direction: column;
   justify-content: center;
   align-items: center;
}

#calculator #screen {
   background: #a2af77;
   height: 20%;
   width: 85%;
   margin: auto;
   margin-bottom: 0;
   border-radius: 10px;
   -webkit-box-shadow: inset 0px 0px 16px -2px rgba(35, 37, 38, 0.75);
   -moz-box-shadow: inset 0px 0px 16px -2px rgba(35, 37, 38, 0.75);
   box-shadow: inset 0px 0px 16px -2px rgba(35, 37, 38, 0.75);
   box-sizing: border-box;
   padding: 15px;
   font-size: 45px;
   text-align: right;
   vertical-align: middle;
   line-height: 200%;
   font-family: "Montserrat", sans-serif;
   overflow: hidden;
   overflow-x: auto;
   white-space: nowrap;
}

#calculator #branding {
   grid-column: 1/3;
   display: flex;
   flex-direction: column;
   align-items: center;
   text-align: center;
   justify-content: center;
}

#calculator #branding h1,
#calculator #branding small {
   margin: 0;
   padding: 0;
   color: #fff;
   font-family: Montserrat, sans-serif;
   text-shadow: 0px 1px 0px rgba(0, 0, 0, 1);
}

#calculator #buttons {
   /*    background: #000; */
   overflow: visible;
   width: 85%;
   margin: auto;
   display: grid;
   grid-template-columns: repeat(4, 75px);
   grid-gap: 15px;
   justify-content: center;
}

button {
   cursor: pointer;
   border: none;
   color: #fff;
   text-align: center;
   font-size: 30px;
   padding: 5px;
   background: #000;
   border-radius: 5px;
   min-height: 50px;
   box-sizing: border-box;
   box-shadow: 2px 2px 3px 1px #232526;
   position: relative;
   left: 0;
   top: 0;
   transition: all 150ms;
   text-align: center;
   font-family: "Montserrat", sans-serif;
   display: flex;
   text-align: center;
   justify-content: center;
   align-items: center;
}

button:hover {
   left: 2px;
   top: 2px;
   box-shadow: 0px 0px 0px 0px #232526;
}

button:focus {
   outline: none;
}

button.btn-hover {
   left: 2px;
   top: 2px;
   box-shadow: 0px 0px 0px 0px #232526;
}

button.btn-grey {
   background: #5d5d5f;
}

button#backspace-btn {
   grid-column: 4/5;
   background: #f65532;
   background: #000;
   border-radius: 50%;
}

button#zero-btn {
   grid-column: 1/3;
}

button#equals-btn {
   grid-column: 4/5;
   grid-row: 5/7;
   background: #f65532;
}

#screen::-webkit-scrollbar-track {
   -webkit-box-shadow: inset 0 0 6px rgba(0, 0, 0, 0.3);
   background-color: #f5f5f5;
}

#screen::-webkit-scrollbar {
   height: 5px;
   background-color: #f5f5f5;
}

#screen::-webkit-scrollbar-thumb {
   background-color: #000;
   background-image: -webkit-gradient(
      linear,
      0 0,
      0 100%,
      color-stop(0.5, rgba(255, 255, 255, 0.2)),
      color-stop(0.5, transparent),
      to(transparent)
   );
}

.cursor {
   animation-name: blink;
   animation-duration: 1s;
   animation-iteration-count: infinite;
}

@keyframes blink {
   0% {
      opacity: 1;
   }

   50% {
      opacity: 0;
   }

   100% {
      opacity: 1;
   }
}