:root 
{
    --chassis: #252527;
    --lcd: #a3b1a3;
    --saffron: #ff9933;
    --green: #138808;
    --btn-num: #ffffff;
}

body 
{
    background: #050505;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    font-family: 'Segoe UI', Arial, sans-serif;
    overflow: hidden;
}

.casio-body 
{
    background: linear-gradient(145deg, #3a3a3c, #1a1a1c);
    width: 380px;
    padding: 30px 20px;
    border-radius: 40px;
    border: 3px solid #444;
    box-shadow: 0 30px 60px rgba(0,0,0,0.8);
    position: relative;
    user-select: none;
}

.casio-header
{ 
    display: flex; 
    justify-content: space-between; 
    align-items: center; 
    color: white; 
    margin-bottom: 15px; 
}


.left-brand
{ 
    font-size: 24px; 
    font-weight: 900; 
    letter-spacing: 1px; 
}

.edition
{ 
    font-size: 11px; 
    color: var(--saffron); 
    font-weight: bold; 
}




.solar-strip 
{
    background: #111;
    width: 110px;
    height: 28px;
    margin: 0 0 15px auto;
    display: flex;
    border: 2px solid #000;
}

.solar-strip .cell
{ 
    flex: 1; 
    border-right: 1px solid #333; 
}

.lcd-screen 
{
    background: var(--lcd);
    background-image: radial-gradient(#94a394 1px, transparent 0);
    background-size: 3px 3px;
    border: 6px solid #111;
    border-radius: 8px;
    padding: 15px;
    box-shadow: inset 0 0 20px rgba(0,0,0,0.5);
    margin-bottom: 25px;
    position: relative;
}

.lcd-top
{ 
    display: flex; 
    justify-content: space-between; 
    font-size: 10px; 
    font-weight: bold; 
    color: #333; 
}




#display 
{
    width: 100%; 
    background: transparent; 
    border: none; 
    text-align: right;
    font-family: 'Courier New', monospace; 
    font-size: 30px; 
    font-weight: bold;
    color: #111; 
    outline: none; 
    margin-top: 5px;
}



#error-msg 
{ 
    height: 14px; 
    color: #8b0000; 
    font-size: 10px; 
    font-weight: bold; 
}

.keypad 
{ 
    display: grid; 
    grid-template-columns: repeat(4, 1fr); 
    gap: 12px; 
    min-height: 320px; 
}

button 
{
    padding: 16px 0; 
    border-radius: 12px; 
    border: none; 
    font-weight: bold;
    cursor: pointer; 
    box-shadow: 0 5px 0 #000; 
    transition: 0.1s;
}

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

.btn-num 
{ 
    background: var(--btn-num); 
    color: #000; 
    font-size: 18px; 
}

.btn-op 
{ 
    background: #444; 
    color: #fff; 
}

.btn-sci 
{ 
    background: #333; 
    color: #fff; 
    font-size: 12px; 
}

.btn-mode
{ 
    background: var(--saffron); 
    color: #000; 
    font-size: 20px; 
}

.btn-eq
{ 
    background: var(--green); 
    color: #fff; 
}

.btn-back 
{ 
    background: #b91c1c; 
    color: #fff; 
}


.developer-tag 
{ 
    text-align: center; 
    color: #fbbf24; 
    font-size: 12px; 
    font-weight: bold; 
    margin-top: 20px; 
    letter-spacing: 2px; 
}



.nested-input 
{ 
    background: #222; 
    color: var(--saffron); 
    border: 1px solid #444; 
    width: 100%; 
    text-align: center; 
    padding: 10px; 
    border-radius: 5px; 
    grid-column: span 4; 
    margin-bottom: 5px; 
}