:root {
  --black: rgba(#000, 0.4);
}
html {
  --bg: #f5f6f7;
  --color-text: #9c9c9c;
  --color-orange: #ff6a00;
  --color-shadow: -4px -2px 4px 0px #ffffff, 4px 2px 6px 0px #dfe4ea;
  --color-inset-shadow: inset -2px -2px 6px rgba(255, 255, 255, 0.8),
    inset 2px 2px 6px rgba(0, 0, 0, 0.1);
  --color-equal-shadow: -2px -2px 6px rgba(3, 169, 244, 0.1),
    2px 2px 6px rgba(0, 0, 0, 0.3);
  --color-equal-inset-shadow: inset -2px -2px 6px rgba(255, 255, 255, 0.5),
    inset 2px 2px 6px rgba(0, 0, 0, 0.3);
}
html[data-theme="dark"] {
  --bg: #131419;
  --color-text: #ffffff;
  --color-orange: #ff6a00;
  --color-shadow: -3px -3px 10px rgba(255, 255, 255, 0.07),
    3px 3px 15px rgba(0, 0, 0, 0.5);
  --color-inset-shadow: inset -2px -2px 6px rgba(255, 255, 255, 0.01),
    inset 2px 2px 6px rgba(0, 0, 0, 0.8);
  --color-equal-shadow: -2px -2px 6px rgba(3, 169, 244, 0.01),
    2px 2px 6px rgba(0, 0, 0, 0.8);
  --color-equal-inset-shadow: inset -2px -2px 6px rgba(255, 106, 0, 0.2),
    inset 2px 2px 6px rgba(0, 0, 0, 0.5);
}
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
body {
  background: var(--bg);
  font-family: "Poppins", sans-serif;
  height: 100vh;
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
}
.main {
  width: 300px;
  height: 560px;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  border-radius: 10px;
  background: var(--bg);
  box-shadow: var(--color-shadow);
  overflow: hidden;
}
.heading {
  height: 60px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: relative;
  padding: 0px 28px;
}
.heading span {
  color: var(--color-text);
  font-size: 18px;
}
.heading span:nth-child(1),
.heading span:nth-child(3) {
  cursor: pointer;
  font-size: 15px;
}
.heading span:nth-child(2) {
  margin-top: 5px;
}
.heading span:nth-child(2)::after {
  width: 115px;
  content: "";
  position: absolute;
  bottom: -5%;
  border-bottom: 3px solid var(--color-orange);
  z-index: 10;
  left: 30%;
  border-radius: 10px;
}
.result {
  height: 160px;
  position: relative;
  background: var(--bg);
  border-top: 3px solid rgba(0, 0, 0, 0.05);
  border-bottom: 3px solid rgba(0, 0, 0, 0.05);
}
.result input {
  height: 100%;
  width: 100%;
  background: transparent;
  border: none;
  outline: none;
  position: absolute;
  text-align: right;
  bottom: 2%;
  right: 5%;
  font-size: 32px;
  color: var(--color-text);
}
#keyboard {
  padding: 30px 20px;
}
#keyboard input[type="button"] {
  outline: none;
}
.top-section {
  height: auto;
  position: relative;
  display: flex;
  justify-content: space-around;
  padding: 4px 6px;
  border-radius: 30px;
  margin-left: 10px;
  background: var(--bg);
  box-shadow: var(--color-shadow);
}
.top-section input[type="button"] {
  margin-top: 2px;
}
.middle-section {
  position: relative;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  align-items: center;
  border-radius: 30px;
  margin-top: 2px;
  margin-left: 10.4px;
}
.middle-section input[type="button"] {
  margin: 5px 5px;
  color: var(--color-text);
  font-weight: 600;
}
.side-section {
  float: left;
  height: 270px;
  position: relative;
  display: flex;
  flex-direction: column;
  padding: 5px 4px;
  border-radius: 30px;
  justify-content: space-between;
  margin-left: 15px;
  background: var(--bg);
  box-shadow: var(--color-shadow);
}
.side-section input[type="button"] {
  margin-left: 2px;
}
.group {
  width: 185px;
  float: left;
}
input[type="button"] {
  width: 45px;
  height: 45px;
  border-radius: 50%;
  border: none;
  background-color: var(--bg);
  font-weight: 900;
  font-size: 18px;
  cursor: pointer;
  box-shadow: var(--color-shadow);
}
input[type="number"]::-webkit-outer-spin-button,
input[type="number"]::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}
.equal {
  background-color: var(--color-orange) !important;
  color: #fff !important;
  box-shadow: var(--color-equal-shadow) !important;
}
#operator {
  color: var(--color-orange);
}
input[type="button"]:active,
input[type="button"]:hover {
  box-shadow: var(--color-inset-shadow);
}
input[name="btn-equal"]:active,
input[name="btn-equal"]:hover {
  background: var(--color-orange) !important;
  box-shadow: var(--color-equal-inset-shadow) !important;
}
.fas {
  cursor: pointer;
}
label input[type="checkbox"] {
  -webkit-appearance: none;
}
label input[type="checkbox"]:checked ~ .fas {
  color: var(--color-orange);
}