*{
    margin: 0;
    padding: 0;
}
body{
    background: linear-gradient(135deg, #0a0a0a 0%, #1a1a2e 100%);
    display: grid;
    height: 100vh;
    place-items: center;
    font-family: Consolas, "Lucida Console", Monaco, "Courier New", monospace;
}
.container{
    width: 300px;
    background: rgba(255, 255, 255, 0.08);
    backdrop-filter: blur(10px);
    border: 2px solid rgba(255, 255, 255, 0.15);
    border-radius: 20px;
    overflow: hidden;
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.3);
}

#display{
    padding: 10px 10px;
    background-color: rgba(255, 255, 255, 0.95);
    border: 2px solid rgba(255, 255, 255, 0.3);
    text-align: end;
    font-size: 3rem;
    font-weight: 600;
    color: #333;
    position: relative;
}

#operator-display{
    position: absolute;
    top: 0;
    right: 15px;
    font-size: 1rem;
    color: #74b9ff;
    font-weight: bold;
    min-width: 20px;
}

#keys{
    color: white;
    font-size: 2rem;
    text-align: center;
    user-select: none;
}
table{
    border-collapse: collapse;
    width: 100%;
    height: 350px;
}
td{
    border: 1px solid rgba(212, 175, 55, 0.3);
    background-color: rgba(255, 255, 255, 0.08);
    cursor: pointer;
    color: white;
    font-weight: 600;
    transition: all 0.3s ease;
    width: 25%;
}
td:hover{
    background-color: rgba(212, 175, 55, 0.15);
    box-shadow: inset 0 0 10px rgba(212, 175, 55, 0.2);
}
td:active{
    background-color: rgba(255, 255, 255, 0.35);
    transform: scale(0.98);
}

/* Function buttons (C, DEL) */
td.function{
    border: 1px solid rgba(231, 76, 60, 0.4);
    background-color: rgba(231, 76, 60, 0.15);
    color: #ff6b6b;
}
td.function:hover{
    background-color: rgba(231, 76, 60, 0.25);
    box-shadow: inset 0 0 10px rgba(231, 76, 60, 0.3);
}
td.function:active{
    background-color: rgba(231, 76, 60, 0.35);
}

/* Operator buttons (+, -, *, /) */
td.operator{
    border: 1px solid rgba(52, 152, 219, 0.4);
    background-color: rgba(52, 152, 219, 0.15);
    color: #74b9ff;
}
td.operator:hover{
    background-color: rgba(52, 152, 219, 0.25);
    box-shadow: inset 0 0 10px rgba(52, 152, 219, 0.3);
}
td.operator:active{
    background-color: rgba(52, 152, 219, 0.35);
}

/* Equals button */
td.equals{
    border: 1px solid rgba(39, 174, 96, 0.4);
    background-color: rgba(39, 174, 96, 0.15);
    color: #55efc4;
}
td.equals:hover{
    background-color: rgba(39, 174, 96, 0.25);
    box-shadow: inset 0 0 10px rgba(39, 174, 96, 0.3);
}
td.equals:active{
    background-color: rgba(39, 174, 96, 0.35);
}