/* Body and calculator wrapper */
body {
    margin: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background: linear-gradient(135deg, #09203f, #537895);
    padding: 10px;
    box-sizing: border-box;
}

/* Calculator container */
#calculator {
    font-family: 'Segoe UI', sans-serif;
    background-color: #1c1c1c;
    border-radius: 20px;
    max-width: 350px;
    width: 100%;
    box-shadow: 0 0 20px rgba(0, 0, 0, 0.6);
    overflow: hidden;
}

#calculator h1 {
    display: flex;
    justify-content: center;
    color: white;
    padding: 15px 0;
    font-size: 1.5rem;
}

/* Display */
#display {
    width: 100%;
    padding: 20px;
    font-size: 2.5rem;
    text-align: right;
    border: none;
    background-color: #2e2e2e;
    color: white;
    box-sizing: border-box;
}

/* Grid for keys */
#keys {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    padding: 20px;
    gap: 15px;
}

/* Base button styles */
button {
    height: 60px;
    width: 100%;
    border: none;
    border-radius: 50%;
    background-color: #333;
    color: white;
    font-size: 1.5rem;
    font-weight: bold;
    cursor: pointer;
    transition: background-color 0.2s ease, transform 0.1s ease;
    box-shadow: 0 4px 6px rgba(0,0,0,0.2);
}

button:hover {
    background-color: #444;
}

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

/* Special button styles */
.top {
    background-color: #a5a5a5;
    color: black;
}

.top:hover {
    background-color: #bcbcbc;
}

.top:active {
    background-color: #e0e0e0;
}

/* Operation buttons */
.right {
    background-color: #ff9500;
    color: white;
}

.right:hover {
    background-color: #e08600;
}

.right:active {
    background-color: #cc7700;
}

/* Wide zero button */
button.zero {
    grid-column: span 2;
    border-radius: 30px;
}

/* Toggle switch styling */
.toggle-container {
    display: flex;
    align-items: center;
    justify-content: flex-end;
    padding: 15px 20px 0;
    gap: 10px;
    color: white;
}

.switch {
    position: relative;
    display: inline-block;
    width: 50px;
    height: 25px;
}

.switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.slider {
    position: absolute;
    cursor: pointer;
    top: 0; left: 0;
    right: 0; bottom: 0;
    background-color: #ccc;
    transition: .4s;
    border-radius: 25px;
}

.slider:before {
    position: absolute;
    content: "";
    height: 20px; width: 20px;
    left: 5px; bottom: 3.5px;
    background-color: white;
    transition: .4s;
    border-radius: 50%;
}

input:checked + .slider {
    background-color: #2196F3;
}

input:checked + .slider:before {
    transform: translateX(24px);
}

/* Light mode theme */
.light-mode body {
    background: linear-gradient(135deg, #ffffff, #d0e2f5);
}

.light-mode .toggle-container {
    color: black;
}

.light-mode #calculator h1 {
    color: black;
}

.light-mode #calculator {
    background-color: #f2f2f2;
    box-shadow: 0 0 20px rgba(0, 0, 0, 0.1);
    color: black;
}

.light-mode #display {
    background-color: #e0e0e0;
    color: black;
}

.light-mode .top {
    background-color: #d3d3d3;
    color: black;
}

.light-mode .right {
    background-color: #ff9500;
    color: white;
}

.light-mode button {
    background-color: #f0f0f0;
    color: black;
    box-shadow: 0 5px 7px rgba(0,0,0,0.1);
    border: 1px solid #ccc;

}

.light-mode button:hover {
    background-color: #ccc;
}

.light-mode .mode-label {
    color: black;
}