* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: Arial, sans-serif;
}

body {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background: #f2f2f2;
}

.calculator {
    background: #111;
    padding: 25px;
    border-radius: 15px;
    width: 320px;
    box-shadow: 0px 5px 15px rgba(0,0,0,0.4);
}

.calculator h2 {
    color: black;
    text-align: center;
    margin-bottom: 15px;
}

.calculator h3 {
    color: black;
    font-style: italic;
    font-size: 10px;
    text-align: center;
    margin-top: 5px;
}

/* Light Mode Default */
.calculator, .history {
    background: white;
    color: black;
}


#display {
    width: 100%;
    height: 60px;
    font-size: 22px;
    padding: 10px;
    border: none;
    outline: none;
    border-radius: 10px;
    margin-bottom: 10px;
    text-align: right;
    background: #f2f2f2;
    color: black;

    overflow-x: auto;
    white-space: nowrap;
}

/* Dark Mode */
body.dark-mode {
    background: #0d1117;
}

body.dark-mode .calculator {
    background: dimgray;
}

body.dark-mode .calculator h2 {
    color: white;
    text-align: center;
    margin-bottom: 15px;
}

body.dark-mode .calculator h3 {
    color: white;
    text-align: center;
    margin-bottom: 5px;
}

body.dark-mode #display {
    background: #222;
    color: white;
}

.sci-buttons {
    display: grid;
    grid-template-columns: repeat(6, 1fr);
    gap: 12px;
}

.buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 9px;
}


.btn {
    padding: 8px;
    font-size: 12px;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    background: #333;
    color: white;
    transition: 0.2s;
}

.btn:hover {
    background: #444;
}

.btn-sci {
    background: #4b3fd8;
    padding: 5px;
    font-size: 12px;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    color: white;
    margin-bottom: 5px;
    transition: 0.2s;
}

.btn-sci:hover {
    background: #4b3fd8;
}

.btn-mem {
    background: #fdcb6e;
    padding: 5px;
    font-size: 12px;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    color: black;
    font-weight: bold;
    margin-bottom: 5px;
    transition: 0.2s;
}

.btn-mem:hover {
    background: #e1b44c;
}

.operator {
    background: #00b894;
}

.operator:hover {
    background: #019874;
}

.clear {
    background: crimson;
}

.clear:hover {
    background: darkred;
}

.equal {
    background: darkorange;
    grid-column: span 2; /* Equals button takes two columns */
}

.equal:hover {
    background: orange;
}

.delete {
    background: #333;
    color: white;
    grid-column: span 2; /* Delete button takes two columns */
}

.delete:hover {
    background: #555;
}

.copy-btn {
    background: darkorange;
    grid-column: span 2; /* Copy button takes two columns */
}

.copy-btn:hover {
    background: orange;
}

.dot {
    background: #333;
    color: white;
}

.dot:hover {
    background: #555;
}

.calculator-container {
    display: flex;
    gap: 20px;
    align-items: flex-start;
}

.top-bar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
}

.theme-btn {
    border: none;
    background: #00b894;
    color: white;
    padding: 8px 12px;
    border-radius: 10px;
    cursor: pointer;
    font-size: 16px;
}

.theme-btn:hover {
    background: #019874;
}

#historyList li:hover {
    background: #333;
}

@media (max-width: 768px) {
    .calculator-container {
        flex-direction: column;
        align-items: center;
    }
}