:root {
  /* STATIC SCROLLBAR */
  --scrollbar-theme0: black;
  --scrollbar-thumb-theme0: #6649b8;

  /* STATIC NAVBAR */
  --bg-navbar: #23232e;
  --bg-navbar-logo: #16161d;
  --bg-navbar-hover: #141418;
  --text-navbar: #ececec;
  --text-logo-hover: #ebe6ee;
  --text-theme-hover: white;
  --text-theme: white;
  --theme-logo-primary: #df49a6;
  --theme-logo-secondary: #df49a6;
  --nav-icon-summer: #f4a261;
  ;
  --nav-icon-cool: #457b9d;
  ;
  --nav-icon-dirt: #9c6644;
  ;

  /* TRANSITION SPEEDS */
  --transition-keys: 200ms ease-in-out;
  --transition-navbar: 600ms ease-in-out;
  --transition: 500ms ease-in-out;
}

/* THEMES */
.theme-default {
  --bg-app: linear-gradient(to right, rgb(21, 3, 22), rgb(61, 10, 65));
  --bg-calculator: hsl(0, 3%, 14%);

  --display-text: #ececec;
  --display-brackets: #b6b6b6;
  --keyboard: #333742;
  --operator: hsl(7, 100%, 68%);
  --action: hsl(153, 71%, 59%);
  --key-text: hsl(0, 2%, 75%);
  --key-bg: #262933;
  --glow: rgb(224, 75, 224);
}

.theme-summer {
  /* THEME1 */
  --bg-app: linear-gradient(to right, rgb(21, 3, 22), rgb(216, 145, 51));
  --bg-calculator: hsl(0, 0%, 14%);

  --display-text: #fff6f6;
  --display-brackets: #264653;
  --keyboard: #f4a261;
  --operator: #e76f51;
  --action: #e9c46a;
  --key-text: hsl(0, 0%, 100%);
  --key-bg: #2a9d8f;
  --glow: rgb(59, 211, 231);
}

.theme-cool {
  /* THEME2 */
  --bg-app: linear-gradient(to right, rgb(21, 3, 22), #1d3557);
  --bg-calculator: hsl(0, 0%, 14%);

  --display-text: #ececec;
  --display-brackets: #f1faee;
  --operator: #e63946;
  --action: #a8dadc;
  --key-text: hsl(0, 2%, 75%);
  --key-bg: #457b9d;
  --glow: rgb(142, 223, 243);
}

.theme-dirt {
  /* THEME3 */
  --bg-app: linear-gradient(to right, rgb(21, 3, 22), #7f5539);
  --bg-calculator: hsl(0, 0%, 14%);

  --display-text: #ede0d4;
  --display-brackets: #e6ccb2;
  --operator: #9c6644;
  --action: #ddb892;
  --key-text: hsl(0, 2%, 75%);
  --key-bg: #b08968;
  --glow: rgb(235, 160, 74);
}

* {
  box-sizing: border-box;
  font-family: sans-serif;
}

body {
  margin: 0;
  padding: 0;
  transition: background 500ms ease-in-out, color 1000ms ease-in-out;
}

main {
  margin-left: 5rem;
  padding: 1rem;
}

/* supercool color animation */
@keyframes color-rotate {
  from {
    filter: hue-rotate(0deg);
  }

  to {
    filter: hue-rotate(360deg);
  }
}

.logo:hover {
  animation: color-rotate 1s;
  animation-iteration-count: infinate;
  animation-direction: alternate;
}

.logo-text:hover {
  animation: color-rotate 1s;
  animation-iteration-count: infinate;
  animation-direction: alternate;
}

/* super cool flexible polygon for user */
/* header{
  padding: 1em;
  background: red;
  margin-bottom: 1em;
  padding-bottom: 3.5em;
  clip-path: polygon(50% 0%, 100% 0, 50% 100%, 0 65%, 0 0);
} */

/* Scrollbar */
body::-webkit-scrollbar {
  width: 0.25rem;
}

body::-webkit-scrollbar-track {
  background: var(--scrollbar-theme0);
}

body::-webkit-scrollbar-thumb {
  background: var(--scrollbar-thumb-theme0);
}

/* Navigation menu */
.navbar {
  position: fixed;
  background-color: var(--bg-navbar);
  transition: width var(--transition-navbar);
}

.navbar-nav {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  height: 100%;
}

.nav-item {
  width: 100%;
}

.nav-item:last-child {
  margin-top: auto;
}

.nav-link {
  display: flex;
  align-items: center;
  height: 5rem;
  color: var(--text-navbar);
  text-decoration: none;
  filter: grayscale(100%) opacity(0.7);
  transition: var(--transition-navbar);
}

.nav-link:hover {
  filter: grayscale(0%) opacity(1);
  background: var(--bg-navbar-hover);
  color: var(--text-theme-hover);
  font-size: 1.2rem;
}

.link-text {
  display: none;
  margin-left: 1rem;
}

.nav-link svg {
  width: 2rem;
  min-width: 2rem;
  margin: 0 1.5rem;
}

.fa-primary {
  color: var(--theme-logo-primary);
}

.fa-secondary {
  color: var(--theme-logo-secondary);
}

.fa-primary,
.fa-secondary {
  transition: var(--transition-navbar);
}

.nav-theme-summer {
  color: var(--nav-icon-summer);
}

.nav-theme-cool {
  color: var(--nav-icon-cool);
}

.nav-theme-dirt {
  color: var(--nav-icon-dirt);
}

.logo {
  font-weight: bold;
  text-transform: uppercase;
  margin: 0;
  text-align: center;
  color: var(--text-theme);
  background: var(--bg-navbar-logo);
  font-size: 1.5rem;
  letter-spacing: 0.3ch;
  width: 100%;
}

.logo svg {
  transform: rotate(0deg);
  transition: var(--transition-navbar);
  /* margin-left: 10px; */
}

.logo-text {
  display: inline;
  position: absolute;
  left: -999px;
  transition: var(--transition);
}

.navbar:hover .logo svg {
  transform: rotate(-180deg);
}

/* NAVBAR - Small screens */
@media only screen and (max-width: 600px) {
  .navbar {
    bottom: 0;
    width: 100vw;
    height: 5rem;
  }

  .logo {
    display: none;
  }

  .navbar-nav {
    flex-direction: row;
  }

  .nav-link {
    justify-content: center;
  }

  .calculator {
    margin-bottom: 3rem;
  }
}

/* NAVBAR - Large screens */
@media only screen and (min-width: 600px) {
  .navbar {
    top: 0;
    width: 7rem;
    height: 100vh;
  }

  .navbar:hover {
    width: 18rem;
  }

  .navbar:hover .link-text {
    display: inline;
  }

  .navbar:hover .logo svg {
    margin-left: 12.5rem;
  }

  .navbar:hover .logo-text {
    left: 0px;
  }
}

/* basically  just the view */
.app {
  transition: background 500ms ease-in-out, color 1000ms ease-in-out;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  background: var(--bg-app);
}

.calculator {
  background-color: var(--bg-calculator);
  width: 100%;
  max-width: 375px;
  min-height: 640px;
  display: flex;
  flex-direction: column;
  border-radius: 1.5rem;
  overflow: hidden;
}

/* Display in calculator */
.display {
  min-height: 200px;
  padding: 1.5 rem;
  display: flex;
  justify-content: flex-end;
  align-items: flex-end;
  color: var(--display-text);
  text-align: right;
  flex: 1 1 0%;
}

.display .input {
  font-size: 1.25rem;
  margin-bottom: 0.5rem;

}

.display .output {
  font-size: 3rem;
  font-weight: 700;
  width: 100%;
  max-width: 100%;
  overflow: auto;
}

.display .operator {
  color: var(--operator);
}

.display .brackets {
  color: var(--display-brackets);
}

/* calculator keys */
.keys {
  background-color: var(--keyboard);
  padding: 1.5rem;
  border-radius: 1.5rem 1.5rem 0 0;

  display: grid;
  grid-template-columns: repeat(4, 1fr);
  grid-template-rows: repeat(5, 1fr);
  grid-gap: 1rem;
  box-shadow: 0px -2px 16px var(--glow);
}

.keys .key {
  position: relative;
  cursor: pointer;
  display: block;
  height: 0;
  padding-top: 100%;
  background-color: var(--key-bg);
  border-radius: 1rem;
  transition: .5s;
  user-select: none;

}

.keys .key span {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);

  font-size: 2rem;
  font-weight: 700;
  color: var(--key-text);
}

.keys .key:hover {
  box-shadow: 0px 0px 8px var(--glow);
  transition: var(--transition-keys);
}

.keys .key.operator span {
  color: var(--operator);
}

.keys .key.action span {
  color: var(--action);
}

/* Hidden menus */
.collapsible {
  background-color: #5e8576;
  color: var(--operator-theme0);
  cursor: pointer;
  padding: 1px;
  width: 100%;
  border: none;
  text-align: center;
  outline: none;
  font-size: 15px;
}

/* ARROW KEYS Use in combo with > in HTML */
.arrow {
  border: solid black;
  border-width: 0 3px 3px 0;
  display: inline-block;
  padding: 3px;
}

.right {
  transform: rotate(-45deg);
  -webkit-transform: rotate(-45deg);
}

.down {
  transform: rotate(45deg);
  -webkit-transform: rotate(45deg);
}

.left {
  transform: rotate(-180deg);
  -webkit-transform: rotate(-225deg);
}

.up {
  transform: rotate(-135deg);
  -webkit-transform: rotate(-135deg);
}