styles.css

* {
  background: linear-gradient(90deg, #8e44ad, #c0392b);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen",
    "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue",
    sans-serif;
}

.calc-div {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
}

.row {
  display: flex;
  background: transparent;
}

button {
  border: 2px solid white;
  background: transparent;
  padding: 10px;
  border-radius: 50px;
  font-size: medium;
  color: white;
  font-weight: bold;
  cursor: pointer;
  margin: 5px;
}

span {
  background: transparent;
}

button:hover {
  background-color: white;
  border: 2px solid black;
  -webkit-border-image: linear-gradient(to right, #8e44ad, #c0392b);
  transition: all 0.3s ease-in-out;
}

button:hover > span {
  color: black;
}

h1 {
  color: white;
  background: transparent;
}

#cal_textfield {
  width: 200px;
  height: 20px;
  font-size: 1.5em;
  background: rgba(256, 256, 256, 0.6);
  border: 2px solid white;
  border-radius: 30px;
  padding: 12px;
}

#cal_textfield:focus {
  box-shadow: none;
  outline: none;
}

.buttons {
  margin: 10px;
  background: transparent;
}

.row-end {
  background: transparent;
  display: flex;
  position: relative;
  left: 5;
}