::-webkit-scrollbar {
  width: 10px;
  border-radius: 10px;
  background-color: #685D9E;
}

::-webkit-scrollbar:hover {
  background-color: #57bff3;
}

::-webkit-scrollbar-thumb {
  background: linear-gradient(45deg, #221c42, #423586);
  border-radius: 10px;
}

::-webkit-scrollbar-thumb:hover {
  background: linear-gradient(45deg, #423586, #221c42);
}
body {
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  background-color: #423586;
  font-family: Arial, sans-serif;
  flex-direction: column;
}
.calculator {
  width: 340px;
  background: #5e5186;
  padding: 20px;
  border-radius: 30px;
  box-shadow: 0px 4px 15px rgba(0, 0, 0, 0.5);
  text-align: center;
  margin-top: 5rem;
  margin-bottom: 20px;
}
#display {
  width: 80%;
  height: 80px;
  text-align: right;
  font-size: 2.5em;
  margin-bottom: 15px;
  border: none;
  background: #423586;
  color: white;
  padding: 10px;
  border-radius: 10px;
}
.buttons {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
}
button {
  padding: 20px;
  font-size: 1.8em;
  cursor: pointer;
  border: none;
  background: #423586;
  color: white;
  border-radius: 50%;
  width: 70px;
  height: 70px;
  transition: background 0.2s;
}
button:hover {
  background: #707070;
}
.operator {
  background: #7f6595;
  color: white;
}
.operator:hover {
  background: #4d3164;
}
.clear {
  background: #a5a5a5;
  color: #fff;
}
.clear:hover {
  background: #584b62;
}
.equal {
  background: #7f6595;
  color: white;
}
.equal:hover {
  background: #4d3164;
}
.zero {
  grid-column: span 2;
  width: 150px;
  border-radius: 35px;
}
.history {
  width: 340px;
  background: #423586;
  padding: 10px;
  border-radius: 10px;
  color: white;
  text-align: left;
  max-height: 200px;
  overflow-y: auto;
}
.history h2 {
  text-align: center;
}
.history p {
  margin: 5px 0;
  font-size: 1.2em;
}

.history {
  width: 340px;
  background: #5E5186;
  padding: 10px;
  border-radius: 10px;
  color: white;
  text-align: left;
  max-height: 200px;
  overflow-y: auto;
}
.history h2 {
  text-align: center;
}
.history p {
  margin: 5px 0;
  font-size: 1.2em;
}

.navbar {
  width: 98%;
  position: absolute;
  top: 0;
  left: 0;
  background: rgba(255, 255, 255, 0.2);
  padding: 15px;
  display: flex;
  justify-content: flex-start;
}

/* Back Button */
.back-button {
  background: #2867f0;
  color: white;
  border: none;
  padding: 10px 20px;
  font-size: 16px;
  border-radius: 6px;
  cursor: pointer;
  transition: all 0.3s ease;
  height: 40px;
}

.back-button:hover {
  background: #0190f6;
  transform: scale(1.05);
}

.toggle-btn {
  position: fixed;
  top: 0;
  right: 20px;
  color: white;
  border: none;
  border-radius: 50%;
  width: 50px;
  height: 50px;
  font-size: 30px;
  cursor: pointer;
  transition: 0.3s;
  z-index: 1000;

  /* Centering the icon */
  display: flex;
  align-items: center;
  justify-content: center;
}

/* Toggle theme style */
#toggleTheme {
  background: transparent;
  box-shadow: none;
  position: absolute;
  transition: transform 0.3s ease, opacity 0.3s ease;
}

/* Click animation (subtle scaling effect) */
#toggleTheme:active {
  transform: scale(0.9);
  opacity: 0.7;
}

/* Dark mode effect */
.dark-mode #toggleTheme {
  background: transparent;
  box-shadow: none;
  transition: transform 0.3s ease, opacity 0.3s ease;
}

/* Click animation in dark mode */
.dark-mode #toggleTheme:active {
  transform: scale(0.9);
  opacity: 0.7;
}

.toggle-btn:hover {
  background: #0056b3;
}
body.dark-mode {
  background: #121212;
  color: #fff;
}

body.dark-mode .calculator,
body.dark-mode .history {
  background: #1e1e1e;
}
body.dark-mode #display,
body.dark-mode .buttons button {
  background: #414141;
}