/* Reset */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Instrument Sans', sans-serif;
  font-weight: 200;
}

body {
  background-color: #d2d2d2;
  display: grid;
  place-items: center;
  min-height: 100vh;
}

/* Calculator Frame */
.calculator {
  height: 36rem;
  width: 26rem;
  padding: 1rem;
  border-radius: 1rem;
  background-color: #caa4a4;
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}

/* Top Bar */
.top-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
}

#theme-toggle,
#camera-btn {
  width: 3rem;
  height: 3rem;
}

#mode-btn {
  font-size: 1.1rem;
  font-weight: 600;
  width: 9rem;
  height: 3rem;
}

/* Base Button */
.btn {
  cursor: pointer;
  border: none;
  border-radius: 1rem;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 2px 2px 0 #2b2b2b;
  transition: all 0.1s ease;
}

.btn:active {
  transform: translate(3px, 3px);
  box-shadow: 2px 2px 0 #a9a9a9;
}

/* Color Variants */
.gray-btn {
  background-color: #ececec;
}
.gray-btn:hover {
  background-color: #ddd;
}

.accent-btn {
  background-color: #CF0A0A; /* red accent */
  color: white;
}
.accent-btn:hover {
  background-color: #e24848;
}

.dark-btn {
  background-color: #000;
  color: white;
}
.dark-btn:hover {
  background-color: #343434;
}

/* Icon Buttons */
#theme-toggle img,
#camera-btn img {
  width: 1.5rem;
  height: 1.5rem;
}

/* Display */
.display {
  height: 7rem;
  width: 100%;
  background-color: #fff;
  border: 0.1rem solid #eee;
  border-radius: 0.5rem;
  margin-bottom: 1rem;
  padding: 1rem;
  text-align: right;
  font-size: 2rem;
  overflow: hidden;
}
#expression {
  color: #888;
  font-size: 1.5rem;
}
#result {
  color: #333;
  font-size: 2rem;
}

/* Buttons Grid */
.buttons {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.5rem;
}
.buttons button {
  height: 4rem;
  font-size: 1.5rem;
  border-radius: 2rem;
}