style.css

body {
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  background-color: white;
}

.text {
  text-align: center;
  font-style: italic;
  font-weight: bolder;
  font-size: 15px;
}

#display {
  display: flex;
}

.inp {
  width: 100%;
  justify-content: center;
  text-align: center;
  align-items: center;
  justify-content: space-around;
  background-color: lightblue;
  top: 0;
  position: fixed;
}

.inp input {
  justify-content: start;
  height: 30px;
  width: 150px;
}
input[type="number"]::-webkit-outer-spin-button,
input[type="number"]::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

button {
  background-color: yellowgreen;
  width: 100px;
  height: 35px;
  color: white;
  font-size: 15px;
  border-radius: 10%;
  border: none;
}

button:hover {
  background-color: darkmagenta;
  color: aqua;
}

#dis {
  display: flex;
}

#container {
  display: flex;
  flex-wrap: wrap;
}

#tab {
  margin-top: 140px;
}

@media (max-width: 768px) {
  body {
    min-height: 100vh;
    display: block;
    justify-content: center;
    align-items: center;
    background-color: white;
  }

  .inp input {
    width: 70px;
  }
  .text {
  text-align: center;
  font-style: italic;
  font-weight: bolder;
  font-size: 15px;
}

  .inp {
   width: 100%;
  justify-content: center;
  text-align: center;
  align-items: center;
  justify-content: space-around;
  background-color: lightblue;
  top: 0;
  position: fixed;
  }

  #display {
    display: block;
  }

  #dis {
    display: block;
  }

  #container {
    display: block;
  }
}