:root {
  --bg-light: linear-gradient(135deg, #f9c5d1, #f6e7f7);
  --calc-bg: white;
  --btn-bg: #ffe6f2;
  --btn-hover: #ffcce1;
  --operator-bg: #d6b3ff;
  --operator-hover: #b48aff;
  --equal-bg: #90e0ef;
  --equal-hover: #48cae4;
  --clear-bg: #ffb3b3;
  --clear-hover: #ff8080;
  --text-color: #555;
  --title-color: #d63384;
}

body.dark {
  --bg-light: linear-gradient(135deg, #2e2b4f, #1a1a2e);
  --calc-bg: #22223b;
  --btn-bg: #39375b;
  --btn-hover: #4a4e69;
  --operator-bg: #7b2cbf;
  --operator-hover: #9d4edd;
  --equal-bg: #00b4d8;
  --equal-hover: #0077b6;
  --clear-bg: #ef476f;
  --clear-hover: #d90429;
  --text-color: #fff;
  --title-color: #fcbf49;
}

body {
  background: var(--bg-light);
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  margin: 0;
  font-family: "Poppins", sans-serif;
  transition: background 0.5s ease;
}

/* Calculator Container */
.calculator {
  background: var(--calc-bg);
  border-radius: 25px;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
  padding: 25px;
  width: 320px;
  text-align: center;
  transition: 0.3s ease;
}

.calculator:hover {
  transform: translateY(-5px);
  box-shadow: 0 15px 30px rgba(0, 0, 0, 0.15);
}

h1 {
  color: var(--title-color);
  font-weight: 700;
  margin-bottom: 20px;
}

input {
  width: 100%;
  height: 60px;
  border: none;
  border-radius: 15px;
  background: #f9f9f9;
  margin-bottom: 15px;
  font-size: 1.5rem;
  text-align: right;
  padding-right: 15px;
  box-shadow: inset 0 2px 5px rgba(0, 0, 0, 0.05);
  outline: none;
}

/* Buttons Layout */
.buttons {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
}

button {
  height: 60px;
  border: none;
  border-radius: 15px;
  background: var(--btn-bg);
  font-size: 1.2rem;
  font-weight: 600;
  cursor: pointer;
  color: var(--text-color);
  transition: all 0.2s ease;
}

button:hover {
  background: var(--btn-hover);
  transform: scale(1.05);
}

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

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

.equal {
  background: var(--equal-bg);
  color: white;
  grid-column: span 2;
}

.equal:hover {
  background: var(--equal-hover);
}

.clear {
  background: var(--clear-bg);
  color: white;
}

.clear:hover {
  background: var(--clear-hover);
}

/* Toggle Button */
.toggle {
  position: absolute;
  top: 20px;
  right: 20px;
  background: var(--calc-bg);
  border-radius: 20px;
  width: 55px;
  height: 28px;
  display: flex;
  align-items: center;
  cursor: pointer;
  padding: 4px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
  transition: all 0.4s ease;
}

.toggle-ball {
  width: 20px;
  height: 20px;
  background: var(--title-color);
  border-radius: 50%;
  transition: transform 0.3s ease;
}

body.dark .toggle-ball {
  transform: translateX(28px);
}