:root {
  --primary-color: #3498db;
  --secondary-color: #2ecc71;
  --dark-color: #2c3e50;
  --light-color: #ecf0f1;
  --danger-color: #e74c3c;
  --warning-color: #f39c12;
  --info-color: #1abc9c;
  --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
  --border-radius: 8px;
  --transition: all 0.2s ease;
}

[data-theme="light"] {
  --bg-color: #f8f9fa;
  --text-color: #212529;
  --calculator-bg: #ffffff;
  --btn-bg: #f8f9fa;
  --btn-hover: #e9ecef;
  --display-bg: #f8f9fa;
  --scientific-btn: #e3f2fd;
  --programmer-btn: #fff8e1;
  --primary-color: #3498db;
  --secondary-color: #2ecc71;
  --danger-color: #e74c3c;
  --warning-color: #f39c12;
  --info-color: #1abc9c;
  --error-color: #dc3545;
}

[data-theme="dark"] {
  --bg-color: #343a40;
  --text-color: #f8f9fa;
  --calculator-bg: #495057;
  --btn-bg: #6c757d;
  --btn-hover: #5a6268;
  --display-bg: #343a40;
  --scientific-btn: #1e3a8a;
  --programmer-btn: #78350f;
  --primary-color: #5dade2;
  --secondary-color: #58d68d;
  --danger-color: #ec7063;
  --warning-color: #f5b041;
  --info-color: #48c9b0;
  --error-color: #ff6b6b;
}

[data-theme="professional"] {
  --bg-color: #f0f2f5;
  --text-color: #333;
  --calculator-bg: #ffffff;
  --btn-bg: #f8f9fa;
  --btn-hover: #e9ecef;
  --display-bg: #f8f9fa;
  --primary-color: #2c3e50;
  --secondary-color: #1abc9c;
  --scientific-btn: #dbeafe;
  --programmer-btn: #fef3c7;
  --danger-color: #e74c3c;
  --warning-color: #f39c12;
  --info-color: #3498db;
  --error-color: #dc3545;
}

[data-theme="vibrant"] {
  --bg-color: #1a1a2e;
  --text-color: #ffffff;
  --calculator-bg: #16213e;
  --btn-bg: #0f3460;
  --btn-hover: #533483;
  --display-bg: #1a1a2e;
  --primary-color: #e94560;
  --secondary-color: #00b894;
  --scientific-btn: #6c5ce7;
  --programmer-btn: #fd79a8;
  --danger-color: #d63031;
  --warning-color: #fdcb6e;
  --info-color: #0984e3;
  --error-color: #ff7675;
}

body {
  background-color: var(--bg-color);
  color: var(--text-color);
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0;
  padding: 20px;
  transition: var(--transition);
}

.calculator-container {
  width: 100%;
  max-width: 600px;
  background-color: var(--calculator-bg);
  border-radius: var(--border-radius);
  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.15);
  padding-bottom: 15px;
  border: 1px solid rgba(0, 0, 0, 0.1);
}

.calculator-header {
  padding: 1rem;
  background: linear-gradient(135deg, var(--primary-color), var(--info-color));
  color: white;
  text-align: center;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.calculator-header h1 {
  margin: 0;
  font-size: 1.8rem;
}

.calculator-controls {
  display: flex;
  justify-content: space-between;
  margin-top: 10px;
  flex-wrap: wrap;
  gap: 5px;
}

.theme-switcher, .mode-switcher {
  display: flex;
  gap: 5px;
  flex-wrap: wrap;
}

.calculator-display {
  padding: 1.5rem;
  text-align: right;
  background-color: var(--display-bg);
  border-bottom: 1px solid rgba(0, 0, 0, 0.1);
  min-height: 100px;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  position: relative;
}

.previous-operand {
  min-height: 24px;
  font-size: 1rem;
  color: rgba(0, 0, 0, 0.7);
  opacity: 0.8;
}

.current-operand {
  font-size: 2.5rem;
  font-weight: 500;
  overflow: hidden;
  text-overflow: ellipsis;
  margin-top: 5px;
}

.current-operand.error {
  color: var(--error-color);
}

.memory-indicator {
  position: absolute;
  top: 10px;
  left: 10px;
  font-size: 0.8rem;
  color: var(--warning-color);
  font-weight: bold;
}

.angle-indicator {
  position: absolute;
  top: 10px;
  right: 10px;
  font-size: 0.8rem;
  color: var(--info-color);
  font-weight: bold;
}

.calculator-buttons {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 8px;
  padding: 1rem;
}

.basic-mode {
  grid-template-columns: repeat(4, 1fr);
}

.programmer-mode {
  grid-template-columns: repeat(4, 1fr);
}

.btn-calculator {
  padding: 1rem;
  font-size: 1.1rem;
  border: none;
  border-radius: var(--border-radius);
  background-color: var(--btn-bg);
  color: var(--text-color);
  cursor: pointer;
  transition: var(--transition);
  box-shadow: var(--shadow);
  border: 1px solid rgba(0, 0, 0, 0.1);
}

.btn-calculator:hover {
  background-color: var(--btn-hover);
  transform: translateY(-2px);
}

.btn-calculator:active {
  transform: translateY(0);
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.btn-operation {
  background-color: var(--primary-color);
  color: white;
}

.btn-operation:hover {
  filter: brightness(1.1);
}

.btn-scientific {
  background-color: var(--scientific-btn);
  color: var(--text-color);
}

.btn-scientific:hover {
  filter: brightness(0.95);
}

.btn-programmer {
  background-color: var(--programmer-btn);
  color: var(--text-color);
}

.btn-programmer:hover {
  filter: brightness(0.95);
}

.btn-equals {
  background-color: var(--secondary-color);
  color: white;
}

.btn-equals:hover {
  filter: brightness(1.1);
}

.btn-zero {
  grid-column: span 2;
}

.btn-number {
  background-color: var(--btn-bg);
}

.btn-number:hover {
  background-color: var(--btn-hover);
}

.memory-buttons {
  display: flex;
  justify-content: center;
  gap: 8px;
  padding: 0 1rem 1rem;
}

.btn-memory {
  padding: 0.5rem 1rem;
  font-size: 0.9rem;
  border: none;
  border-radius: var(--border-radius);
  background-color: var(--warning-color);
  color: white;
  cursor: pointer;
  transition: var(--transition);
  box-shadow: var(--shadow);
}

.btn-memory:hover {
  filter: brightness(1.1);
  transform: translateY(-2px);
}

.scientific-mode, .programmer-mode {
  display: none;
}

.active-mode {
  display: grid;
}

.active {
  background-color: var(--primary-color) !important;
  color: white !important;
  box-shadow: 0 0 0 2px var(--calculator-bg), 0 0 0 4px var(--primary-color);
}

.btn-danger {
  background-color: var(--danger-color) !important;
  color: white !important;
}

.btn-warning {
  background-color: var(--warning-color) !important;
  color: white !important;
}

.btn-info {
  background-color: var(--info-color) !important;
  color: white !important;
}

.btn-secondary {
  background-color: var(--secondary-color) !important;
  color: white !important;
}

@media (max-width: 768px) {
  .calculator-buttons {
      grid-template-columns: repeat(4, 1fr);
  }
  
  .scientific-mode, .programmer-mode {
      grid-template-columns: repeat(4, 1fr);
  }
  
  .calculator-controls {
      flex-direction: column;
      align-items: center;
  }
}

@media (max-width: 480px) {
  .calculator-buttons {
      grid-template-columns: repeat(4, 1fr);
      gap: 6px;
  }
  
  .btn-zero {
      grid-column: span 1;
  }
  
  .calculator-header h1 {
      font-size: 1.5rem;
  }
  
  .btn-calculator {
      padding: 0.8rem;
      font-size: 1rem;
  }
  
  .current-operand {
      font-size: 2rem;
  }
}