.kalk-page-wrapper {
  display: flex;
  align-items: center;
  justify-content: center;
}

.kalk-container {
  background: #000000;
  padding: 25px;
  width: 275px;
  border-radius: 10px;
  color: white;
}

.kalk-text {
  display: block;
  margin-bottom: 20px;
  padding-left: 5px;
  width: 100%;
  font-size: 3.5rem;
  line-height: 1;
  text-align: end;
  background: transparent;
  color: #fff;
  border: none;
  outline: none;
}

button {
  background: #333333;
  color: #fff;
  font-size: 1.5rem;
  border: none;
  border-radius: 70%;
  cursor: pointer;
  height: 65px;
  width: 65px;
}

button:active,
button:focus {
  filter: brightness(120%);
}

.kalk-keys {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-row-gap: 15px;
  grid-column-gap: 10px;
}

.key-operate {
  background: #ff9501;
}

.key-others {
  background: #a6a6a6;
  color: #000000;
}

.feilmelding {
  background:red;
  border-radius:10px;
  color:white;
  padding: 10px;
  display: none;
}

.feilmelding.vis {
  display: block;
}

.stackelem {
    padding: 5px 0;
    border-bottom: 1px solid #222;
    font-size: 3.5rem;
    white-space: nowrap;
    overflow-x: auto;
}

stackelem.longnum {
    font-size: 1.2rem;
}

.stackelem:last-child {
    border-bottom: none;
}