body {
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-image: url('Public/assets/img_2.png');
    background-size: cover;
    background-attachment: fixed;
    background-position: center;
    font-family: 'Segoe UI', 'Helvetica Neue', sans-serif;
    color: white;
}

.calculator-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px;
    width: 100%;
    max-width: 500px;
    padding: 0 20px;
}

.calculator {
    background-color: #121826;
    padding: 30px;
    border-radius: 20px;
    width: 100%;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.5);
}

#display {
    width: calc(100% - 10px);
    height: 100px;
    margin-bottom: 20px;
    padding: 15px;
    font-size: 3em;
    font-weight: 300;
    text-align: right;
    border: none;
    background-color: #1e2a3a;
    color: #4fc3f7;
    border-radius: 12px;
    box-sizing: border-box;
    outline: none;
}

.buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    grid-gap: 12px;
}

button {
    height: 70px;
    font-size: 1.4em;
    font-weight: 600;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    background-color: #2c3e50;
    color: white;
    transition: background-color 0.2s;
}

button:hover {
    background-color: #5c6bc0;
}

button:active {
    background-color: #1a237e;
    transform: scale(0.98);
}

.equals {
    grid-row: span 2;
    background-color: #29b6f6;
}

.equals:hover {
    background-color: #4fc3f7;
}

.equals:active {
    background-color: #0288d1;
}

.zero {
    grid-column: span 2;
    background-color: #37474f;
}

.operator {
    background-color: #5c6bc0;
}

.operator:hover {
    background-color: #7986cb;
}

.operator:active {
    background-color: #3949ab;
}

.info-section {
    text-align: center;
    margin-top: 15px;
    font-size: 0.9em;
    color: #e0e0e0;
}

.github-link {
    margin-top: 10px;
}

.github-link a {
    color: #64b5f6;
    text-decoration: none;
    font-weight: 600;
}

.github-link a:hover {
    text-decoration: underline;
}

.theme-controls {
    margin-top: 15px;
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
    justify-content: center;
}

.theme-controls select,
.theme-controls button {
    padding: 8px 12px;
    border-radius: 6px;
    border: 1px solid #444;
    background-color: #1e2a3a;
    color: white;
    cursor: pointer;
}

.theme-controls select:focus,
.theme-controls button:focus {
    outline: none;
}

details {
    margin-top: 15px;
    background-color: #1e2a3a;
    padding: 12px;
    border-radius: 8px;
    width: 100%;
}

summary {
    font-weight: bold;
    cursor: pointer;
    color: #90caf9;
}

.lab-objective {
    margin-top: 15px;
    background-color: #1e2a3a;
    padding: 12px;
    border-radius: 8px;
    font-size: 0.95em;
    line-height: 1.5;
}