/* Calculator Single Color Design */

.calculator-wrapper {
  /* The "Right half white, left half black" concept applied to the container or grid ? 
       Visual interpretation: 
       Maybe the background of the calculator itself? 
       Let's try a gradient background for the calculator container.
    */
  background: #000000; /* Solid Black */
  padding: 20px;
  border-radius: var(--radius-lg);
  box-shadow: 0 0 50px rgba(0, 0, 0, 0.5); /* Deep shadow */
  width: 320px; /* Fixed width */
  max-width: 100%;
  border: 1px solid #333;
}

.calculator {
  display: flex;
  flex-direction: column;
  gap: 15px;
  /* Ensure content sits on top correctly */
  position: relative;
  z-index: 1;
}

.display {
  background: #111;
  padding: 15px;
  border-radius: var(--radius-sm);
  border: 1px solid #333;
  margin-bottom: 5px;
}

#myInput {
  width: 100%;
  background: transparent;
  border: none;
  color: #fff; /* Always white text on black display */
  font-size: 2.5rem;
  text-align: right;
  font-family: "JetBrains Mono", monospace;
  outline: none;
}

.keys {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
}

/* Button Styling for Single Color Contrast */
button {
  padding: 15px;
  font-size: 1.2rem;
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-family: "JetBrains Mono", monospace;
  transition: all 0.2s;
  font-weight: bold;
}

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

.number-btn {
  background: #1a1a1a;
  color: #fff;
  box-shadow: 0 4px 0 #000;
  border: 1px solid #333;
}

.number-btn:hover {
  background: #222;
  border-color: var(--accent-color);
}

.operator-btn {
  background: #1a1a1a;
  color: var(--accent-color);
  box-shadow: 0 4px 0 #000;
  border: 1px solid #333;
}

.operator-btn:hover {
  background: #222;
  color: #fff;
}

.function-btn {
  background: #222;
  color: #aaa;
  box-shadow: 0 4px 0 #000;
  border: 1px solid #333;
}

.function-btn:hover {
  background: #333;
  color: #fff;
}

.equals-btn {
  background: var(--accent-color);
  color: #000;
  grid-column: span 2;
  box-shadow: 0 4px 0 #009900;
}

.equals-btn:hover {
  opacity: 0.9;
}

/* Zero button - default span (1 col) */
.zero-btn {
  grid-column: span 1;
}