:root {
  --color-main: #3b4664;
  --color-white: #ffffff;

  --bg-main: #181f32;
  --bg-buttons: rgba(37, 45, 68, 0.6);

  --num: #eae3db;
  --number-color: #484b5a;
  --number-border: #b3a599;
  --button-secondary: #647299;
  --border-secondary: #404d70;
  --button-tertiary: #d13f30;
  --border-tertiary: #922417;
  --radio-color: #cf3f34;
}

body[data-theme="light"] {
  --color-main: #e6e6e6;
  --color-white: #3a3a32;

  --bg-main: #eeeeee;
  --bg-buttons: #d3cdcd;

  --num: #e5e4e0;
  --number-color: #3a3a32;
  --number-border: #a69c93;
  --button-secondary: #388187;
  --border-secondary: #1a5d66;
  --button-tertiary: #c85401;
  --border-tertiary: #873a02;
}

body[data-theme="purple"] {
  --color-main: #17062a;
  --color-white: #ffe43b;

  --bg-main: #1e0836;
  --bg-buttons: #1e0836;

  --num: #331b4d;
  --number-color: #ffe537;
  --number-border: #85219b;
  --button-secondary: #56077c;
  --border-secondary: #bf15f4;
  --button-tertiary: #00decf;
  --border-tertiary: #6dfaf1;
  --radio-color: #00e8d8;
}

*,
*::after,
*::before {
  margin: 0;
  padding: 0;
  box-sizing: inherit;
}

html {
  font-size: 62.5%;
}

@media screen and (max-width: 550px) {
  html {
    font-size: 50%;
  }
}

body {
  box-sizing: border-box;
  background-color: var(--color-main);
  color: var(--color-white);

  transition: background-color 0.5s;
}

/* LAYOUT */

.container {
  display: grid;
  justify-content: center;
  align-content: center;
  min-height: 100vh;

  grid-template-columns: repeat(4, 12rem);
  grid-template-rows: 7rem minmax(12rem, auto) auto;
}

.theme {
  grid-row: 2;
  grid-column: 4;

  display: grid;
  grid-template-rows: repeat(2, 1fr);

  justify-items: right;
}

/* HEADER */

.header {
  grid-column: 1/-1;
  align-items: center;

  /* display: flex; */
  /* justify-content: space-between; */

  display: grid;
  grid-template-columns: repeat(4, 1fr);
  grid-template-rows: repeat(2, 1fr);
}

.header h4 {
  grid-row: 2;
  font-size: 3rem;
  margin-bottom: -1.2rem;
}

.header p {
  font-size: 1.2rem;
  font-weight: 800;

  margin-left: 1.5rem;

  grid-row: 2;
  grid-column: 3;

  display: flex;
  align-self: flex-end;
  justify-self: right;
  margin-bottom: 3px;
  margin-right: -5rem;
}

/* DISPLAY */

.display {
  grid-column: 1/-1;

  background-color: var(--bg-main);
  border-radius: 5px;
  padding: 10px;
  margin-top: 1.5rem;

  display: flex;
  flex-direction: column;
  align-items: flex-end;
  justify-content: space-around;

  word-wrap: break-word;
  word-break: break-all;

  margin-bottom: 1.3rem;
}

.display .previousOperand {
  font-size: 2rem;
}

.display .currentOperand {
  font-size: 3rem;
}

/* BUTTONS */

.buttons {
  background-color: var(--bg-buttons);
  grid-column: 1 / -1;

  display: grid;
  grid-gap: 1.5rem;
  border-radius: 5px;

  justify-items: center;
  justify-content: center;

  grid-template-columns: repeat(4, 100px);

  padding: 3rem;
}

.span-2 {
  width: 100%;
  grid-column: span 2;
}

button {
  outline: none;
  cursor: pointer;

  width: 100%;
  padding-top: 0.5rem;
  padding-bottom: 0.5rem;

  background-color: var(--num);
  color: var(--number-color);
  font-size: 3.3rem;
  font-weight: 900;
  border: none;
  border-radius: 10px;

  box-shadow: 0 4px var(--number-border);
}

button:active {
  box-shadow: 0 2px var(--number-border);
}

@media screen and (max-width: 550px) {
  .buttons {
    grid-template-columns: repeat(4, 80px);
  }
  button {
    padding: 0;
    border-radius: 8px;
  }
}

@media screen and (max-width: 415px) {
  .container {
    grid-template-columns: repeat(4, 10rem);
  }
  .buttons {
    grid-template-columns: repeat(4, 65px);
  }
  button {
    padding: 0;
  }

  .radio {
    width: 55% !important;
  }

  .header p {
    margin-right: -4rem;
  }
}
@media screen and (max-width: 370px) {
  .container {
    grid-template-columns: repeat(4, 9rem);
  }
  .buttons {
    grid-template-columns: repeat(4, 55px);
  }
  .radio {
    width: 60% !important;
  }
  .header p {
    margin-right: -3rem;
  }
  button {
    padding: 0;
    border-radius: 8px;
  }
  .blue {
    font-size: 1.8rem !important;
  }
}

.blue {
  background-color: var(--button-secondary);
  color: #ffffff;
  font-size: 2.2rem;
  padding: 1.3rem;
  box-shadow: 0 4px var(--border-secondary);
}

.blue:active {
  box-shadow: 0 2px var(--border-secondary);
}

.red {
  background-color: var(--button-tertiary);
  color: #ffffff;
  font-size: 2.2rem;
  box-shadow: 0 4px var(--border-tertiary);
}

.red:active {
  box-shadow: 0 2px var(--border-tertiary);
}

/* radio */

.radio {
  background-color: var(--bg-buttons);
  padding: 0.4rem 0.4rem 0.3rem 0.3rem;
  border-radius: 0.9rem;

  grid-row: 2;
  grid-column: 1/-1;
  width: 46%;
}

input[type="radio"] {
  -webkit-appearance: none;
  -moz-appearance: none;
  appearance: none;
  opacity: 0;
  cursor: pointer;
  width: 1rem;
  height: 1rem;
  border-radius: 1rem;
  margin-left: 0.4rem;
}
input[type="radio"]:checked {
  display: inline-block;

  opacity: 1;
  background-color: var(--radio-color);
  border-color: var(--radio-color);
}

.labels {
  grid-column: 1/-1;

  letter-spacing: 0.35rem;
  font-size: 1.4rem;
}