@font-face {
    font-family: DS-DIGIB;
    src: url(DS-DIGIB.woff) format('woff');
}

body {
    margin: 0;
    font-family: Arial, sans-serif;
    background: url('https://www.shutterstock.com/image-vector/blue-background-data-flow-binary-600nw-2477227605.jpg') no-repeat center fixed;
    background-size: cover;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
}

.calculator {
    background: linear-gradient(to bottom right, #23032c, #430d80);
    border-radius: 1rem 1rem 1rem 1rem;
    padding: 20px;
    width: 350px;
    box-shadow: 7px 7px 5px #141414;
}
/* Header */
.calculator-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 10px;
}

.calculator-header span {
    font-size: 14px;
    letter-spacing: 2px;
    color: #ffffff;
}

.led-indicator {
    width: 20px;
    height: 12px;
    background: #dbdbe0;
    border-radius: 4px;
    box-shadow: inset 0 0 4px #0c0c0c;
}
.display {
   width: 100%;
    margin: 0.8rem 0;
    padding-top: 1rem;
    padding-right: 2px;
    padding-bottom: 1rem;
    padding-left: 2px;
    font-size: 24px;
    font-family: "DS-DIGIB", monospace;
    text-align: right;
    background: #afe0f1;
    border: 3px solid #1b1b1b;
    border-radius: 10px;
    color: #1a1818;
}

.buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 8px;
}

.btn {
    padding: 18px;
    font-size: 18px;
    border: none;
    border-radius: 50px;
    background: black;
    color: white;
    cursor: pointer;
    transition: background 0.2s, transform 0.1s;
}

.btn:hover {
    transform: scale(1.05);
    background: #5b439c;
}
.btn:active {
    transform: scale(0.95);
}

.btn.action {
    background: linear-gradient(to right, #7a289b, #c069b1);
   color: rgb(19, 18, 18);
     font-weight: 700;
}
.btn.backspace{
    background: linear-gradient(to right, #7a289b, #c069b1);
    color: rgb(19, 18, 18);
    font-weight: 700;
}
.btn.operator {
   background: #e3c1e7;
    color: #141313;
    font-weight: 700;
}
.btn.equal {
    background: linear-gradient(to right, #7a289b, #c069b1);
    color: #000;
    font-family: 'Source Sans Pro', sans-serif;
    font-weight: 700;
}

/* Accessibility */
button.btn:focus {
    outline: 2px solid #f8f3f7;
    outline-offset: 2px;
}

@media (max-width: 400px) {
    .calculator {
        width: 95%;
    }
    .btn {
        font-size: 16px;
        padding: 12px;
    }
}