:root {
    --body: #ffeec4;   /* darker cream */
    --panel: #fff7dc;
    --muted: #5a616b;

    /* Darkened Pastel Colors */
    --yellow: #ffe08a;   /* darker yellow */
    --pink:   #f2a9ce;   /* darker pink */
    --blue:   #a9d3ff;   /* darker blue */
    --orange: #ff965a;   /* darker orange */

    --key-shadow: rgba(33,50,80,0.12);

    --lcd-bg: linear-gradient(#e6edf4,#dfe7ef);
    --lcd-text: #0b2130;

    font-family: "Inter", sans-serif;
}

body {
    margin: 0;
    background: #e8e4f0;
    display: flex;
    justify-content: center;
    padding: 20px;
}

.calc {
    background: var(--body);
    width: 100%;
    max-width: 360px;
    border-radius: 26px;
    padding: 18px;
    box-shadow: 0 10px 35px rgba(0,0,0,0.1);
}

/* LCD SCREEN */
.screen {
    background: #fdfdfd;
    border: 2px solid #dcdcdc;
    border-radius: 12px;
    padding: 10px;
    margin-bottom: 16px;
}

.lcd {
    background: var(--lcd-bg);
    height: 60px;
    border-radius: 12px;
    padding: 10px;
    font-family: "Courier New", monospace;
    font-size: 32px;
    text-align: right;
    color: var(--lcd-text);
    display: flex;
    align-items: center;
    justify-content: flex-end;
    letter-spacing: 2px;
    overflow: hidden;
}

/* KEYS GRID */
.keys {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 14px;
}

.btn {
    aspect-ratio: 1/1;
    border-radius: 50%;
    border: none;
    font-size: 17px;
    display: flex;
    justify-content: center;
    align-items: center;
    box-shadow: 0 6px 14px var(--key-shadow), inset 0 -6px 10px rgba(255,255,255,0.6);
    cursor: pointer;
    font-weight: 500;
    transition: 0.1s;
}

.btn:active {
    transform: translateY(4px);
    box-shadow: none;
}

/* Dark Pastel Colors */
.y { background: var(--yellow); }
.p { background: var(--pink); }
.b { background: var(--blue); }
.o { background: var(--orange); }

/* Wide zero button */
.span2 {
    grid-column: span 2;
    aspect-ratio: unset;
    height: 56px;
    border-radius: 30px;
}