* { 
  box-sizing: border-box; 
  font-family: system-ui, -apple-system, sans-serif; 
}

.calculator-container { 
  display: flex; 
  flex-direction: column;
  justify-content: center; 
  align-items: center; 
  min-height: 80vh; 
  padding: 20px; 
}

.calculator { 
  background: #fff; 
  padding: 20px; 
  border-radius: 12px; 
  box-shadow: 0 4px 15px rgba(0,0,0,0.1); 
  width: 100%;
  max-width: 360px; 
}

#display { 
  width: 100%; 
  height: 50px; 
  font-size: 1.3rem; 
  text-align: right; 
  padding: 10px; 
  border: 1px solid #ccc; 
  border-radius: 6px; 
  margin-bottom: 15px; 
  outline: none; 
  background-color: #fcfcfc;
}

.grid { 
  display: grid; 
  grid-template-columns: repeat(4, 1fr); 
  gap: 8px; 
}

button { 
  padding: 12px 5px; 
  font-size: 0.95rem; 
  border: none; 
  background: #e0e0e0; 
  border-radius: 6px; 
  cursor: pointer; 
  transition: background 0.2s; 
  font-weight: 500; 
}

button:hover { 
  background: #d0d0d0; 
}

button.op { 
  background: #ff9500; 
  color: white; 
}

button.op:hover { 
  background: #e08500; 
}

button.func { 
  background: #5ac8fa; 
  color: white; 
}

button.func:hover { 
  background: #32ade6; 
}

button.clear { 
  background: #ff3b30; 
  color: white; 
}

button.clear:hover {
  background: #d32f2f;
}

/* Panduan Sintaks / Tutorial Styling */
.tutorial-card {
  background: #ffffff;
  margin-top: 20px;
  padding: 18px 20px;
  border-radius: 12px;
  box-shadow: 0 4px 15px rgba(0,0,0,0.05);
  width: 100%;
  max-width: 360px;
  font-size: 0.88rem;
  color: #333;
}

.tutorial-card h3 {
  margin-top: 0;
  margin-bottom: 10px;
  font-size: 1rem;
  color: #111;
  border-bottom: 2px solid #f0f0f0;
  padding-bottom: 6px;
}

.tutorial-card ul {
  margin: 0;
  padding-left: 18px;
}

.tutorial-card li {
  margin-bottom: 6px;
  line-height: 1.35;
}

.tutorial-card code {
  background: #f0f0f5;
  padding: 2px 6px;
  border-radius: 4px;
  font-family: monospace;
  color: #d63384;
  font-weight: bold;
}