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

body {
  background-color: #8bc6ec;
  min-height: 100vh;
  display: flex;
  justify-content: center;
}

.container {
  background: #000000;
  padding: 15px;
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.calc-text {
  margin-bottom: 15px;
  padding-left: 10px;
}

.calc-text p {
  width: 100%;
  font-size: 3rem;
  text-align: right;
  background: transparent;
  color: #fff;
  border: none;
  outline: none;
  word-wrap: break-word;
  word-break: break-all;
}

button {
  background: #333333;
  color: #fff;
  font-size: 1.3rem;
  border: none;
  border-radius: 50%;
  cursor: pointer;
  height: 50px;
  width: 50px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto;
}

button:active {
  filter: brightness(140%);
}

.calc-keys {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    grid-row-gap: 12px;
    grid-column-gap: 8px;
    width: 100%;
}

.key-zero {
    grid-column: span 2;
    width: 100%;
    border-radius: 25px;
    justify-content: flex-start;
    padding-left: 20px;
}

.key-operate {
    background: #ff9501;
}

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