:root {
  --bg-dark: #1c2526;
  --button-bg: #2d3839;
  --text-light: #ffffff;
  --operator-color: #ff9500;
  --sci-button-color: #6b7280;
  --button-size: 60px;
  --button-spacing: 10px;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: "Montserrat", Arial, sans-serif;
  background-color: var(--bg-dark);
  color: var(--text-light);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
}

.calculator-container {
  display: flex;
  gap: 20px;
  max-width: 800px;
  width: 100%;
  padding: 20px;
}

.calculator {
  background-color: var(--button-bg);
  padding: 20px;
  border-radius: 20px;
  width: 400px;
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.3);
}

.calculator-title {
  font-size: 24px;
  text-align: center;
  margin-bottom: 20px;
  color: var(--text-light);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
}

.display {
  background-color: rgba(0, 0, 0, 0.2);
  padding: 20px;
  border-radius: 10px;
  margin-bottom: 20px;
  position: relative;
}

.expression {
  font-size: 14px;
  opacity: 0.7;
  min-height: 20px;
  text-align: right;
}

.result {
  font-size: clamp(24px, 5vw, 36px);
  font-weight: bold;
  text-align: right;
  overflow: hidden;
  text-overflow: ellipsis;
}

.buttons {
  display: grid;
  gap: var(--button-spacing);
}

.basic-buttons {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--button-spacing);
}

button {
  width: var(--button-size);
  height: var(--button-size);
  border-radius: 50%;
  border: none;
  background-color: var(--button-bg);
  color: var(--text-light);
  font-size: 20px;
  cursor: pointer;
  transition: transform 0.1s ease, background-color 0.2s;
}

button:hover {
  background-color: rgba(255, 255, 255, 0.1);
}

button:active {
  transform: scale(0.95);
}

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

.equals {
  background-color: var(--operator-color);
}

.wide {
  grid-column: span 2;
  width: calc(var(--button-size) * 2 + var(--button-spacing));
  border-radius: 30px;
}

.scientific-buttons {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--button-spacing);
  margin-top: var(--button-spacing);
  background-color: rgba(0, 0, 0, 0.1);
  padding: var(--button-spacing);
  border-radius: 10px;
}

.sci-op {
  background-color: var(--sci-button-color);
  font-size: 16px;
}

.sci-op:hover {
  background-color: var(--sci-button-color);
  opacity: 0.8;
}

.hidden {
  display: none;
}

.scientific-buttons.hidden {
  display: none;
  opacity: 0;
  transform: translateY(-20px);
}

.scientific-buttons {
  opacity: 1;
  transform: translateY(0);
  transition: opacity 0.3s ease, transform 0.3s ease;
}

.memory-indicator {
  position: absolute;
  top: 10px;
  left: 10px;
  font-size: 12px;
  opacity: 0;
  transition: opacity 0.2s;
}

.memory-active {
  opacity: 1;
}

.history-panel {
  width: 300px;
  background-color: var(--button-bg);
  padding: 20px;
  border-radius: 20px;
}

.history-list {
  list-style: none;
}

.history-list li {
  padding: 10px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
  cursor: pointer;
}

.history-list li:hover {
  background-color: rgba(255, 255, 255, 0.1);
}

.calculator-footer {
  text-align: center;
  margin-top: 20px;
  font-size: 14px;
  color: var(--text-light);
  opacity: 0.7;
  position: fixed;
  bottom: 20px;
  width: 100%;
}

.credit-link {
  color: var(--operator-color);
  text-decoration: none;
  font-weight: 700;
  transition: opacity 0.2s ease;
}

.credit-link:hover {
  opacity: 0.8;
}

@media (max-width: 768px) {
  .calculator-container {
    flex-direction: column;
  }

  .calculator {
    width: 100%;
  }

  :root {
    --button-size: 50px;
  }
}

@media (max-width: 480px) {
  :root {
    --button-size: 45px;
    --button-spacing: 8px;
  }

  .calculator {
    padding: 15px;
  }
}