:root {
    --blue: #0088ff;
    --white: #ffffff;
    --light-blue: #e1e4e7;
    --shadow: rgba(0, 0, 0, 0.2);
}

body {
    background-color: var(--light-blue);
    font-family: Arial, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
}

.calculator {
    background-color: var(--white);
    padding: 20px;
    border-radius: 15px;
    box-shadow: 0 4px 15px var(--shadow);
    width: 300px;
}

#display {
    width: 100%;
    height: 50px;
    font-size: 1.5rem;
    margin-bottom: 15px;
    text-align: right;
    padding: 10px;
    border: none;
    border-radius: 8px;
    background: var(--light-blue);
}

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

button {
    padding: 15px;
    font-size: 1.2rem;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: 0.2s;
}

button:hover {
    transform: scale(1.05);
}

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

.btn.function {
    background-color: #ff4d4d;
    color: var(--white);
}

.btn.equal {
    background-color: green;
    color: var(--white);
    grid-row: span 2;
}

.zero {
    grid-column: span 2;
}

footer {
  background-color: #007bff; /* Bleu */
  color: white;
  text-align: center;
  padding: 10px;
  font-size: 14px;
  position: fixed;
  bottom: 0;
  left: 0;
  width: 100%;
}

body {
  margin-bottom: 50px; /* éviter que le footer cache le contenu */
}