@media screen and (max-width: 420px) {
  body {
    width: 100%;
    max-height: 100vh;
    overflow: hidden;
  }
  .main-container {
    display: flex;
    flex-direction: column;
    justify-content: flex-start;
    width: 100%;
    height: 100%;
    padding: 10px;
    border-radius: 0 !important;
  }
}

* {
  padding: 0;
  margin: 0;
  box-sizing: border-box;
  font-family: "Times New Roman", Times, serif;
}

body {
  width: 100%;
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
}

.main-container {
  padding: 20px;
  padding-top: 40px;
  border-radius: 10px;
  background-color: #17153b;
}

.input-box {
  width: 100%;
  display: flex;
  flex-direction: column;
  box-shadow: inset 0px 0px 10px rgba(255, 255, 255, 0.1);
  border-radius: 10px;
}

.input-pre {
  height: 40px;
  font-size: 16px;
  border: none;
  text-align: right;
  padding: 10px 20px 10px 10px;
  font-weight: bold;
  border-radius: 8px 8px 0 0;
  background-color: transparent;
  color: rgba(255, 255, 255, 0.8);
}

.input-nex {
  height: 60px;
  border: none;
  font-weight: bold;
  font-size: 24px;
  text-align: end;
  padding: 10px 20px 10px 10px;
  border-radius: 0 0 8px 8px;
  background-color: transparent;
  color: #fff;
}

.row {
  width: 100%;
  display: flex;
}

.numbers {
  padding: 0;
  margin: 0;
}

.buttons {
  margin-top: 30px;
}

.btn,
.delete,
.operator,
.clear {
  background-color: #f0f0f0;
  width: 40%;
  height: 80px;
  border: 1px solid rgba(0, 0, 0, 0.1);
  font-size: 16px;
  font-weight: bold;
  transition: background-color 0.2s ease;
}

.btn:hover,
.delete:hover,
.operator:hover,
.clear:hover {
  cursor: pointer;
}

.btn:active {
  background-color: rgba(240, 240, 240, 0.8);
}

.delete:active,
.clear:active {
  background-color: rgba(204, 204, 204, 0.8);
}

.equal:active {
  background-color: rgba(0, 0, 255, 0.8);
}

.operator:active {
  background-color: rgba(254, 146, 65, 0.8);
}

.equal {
  width: 80%;
  height: 80px;
  background-color: #0000ff;
  border: 1px solid rgba(0, 0, 0, 0.1);
  color: #fff;
  font-size: 20px;
  font-weight: bold;
}

.operator {
  background-color: #fe9241;
  font-size: 18px;
  font-weight: 700;
  color: #fff;
}

.delete {
  background-color: #ccc;
  border: 1px solid rgba(0, 0, 0, 0.1);
}

.clear {
  background-color: #ccc;
  border: 1px solid rgba(0, 0, 0, 0.1);
  font-size: 16px;
  font-weight: bold;
}