@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600&display=swap');

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', sans-serif;
}

body {
    height: 100vh;
    background: linear-gradient(135deg, #000000 0%, #200000 100%);
    display: flex;
    justify-content: center;
    align-items: center;
}

.game-box {
    width: 400px;
    background: rgba(20,0,0,0.95);
    border-radius: 20px;
    padding: 30px;
    box-shadow:
        0 0 20px rgba(255,0,0,0.2),
        0 20px 50px rgba(100,0,0,0.7);
    display: flex;
    flex-direction: column;
    align-items: center;
    transition: all 0.3s ease;
}

.game-box:hover {
    box-shadow:
        0 0 25px rgba(255,0,0,0.3),
        0 25px 60px rgba(120,0,0,0.8);
}

/* DISPLAY */
#display {
    width: 100%;
    padding: 20px;
    font-size: 24px;
    border-radius: 12px;
    border: none;
    outline: none;
    text-align: right;
    color: #ff9999;
    background: #1a0000;
    margin-bottom: 20px;
    box-shadow: inset 0 0 10px rgba(255,0,0,0.3);
}

/* BUTTON CONTAINER */
.game-box > div {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    grid-gap: 12px;
    width: 100%;
}

/* BUTTONS */
button {
    padding: 20px;
    font-size: 18px;
    font-weight: 600;
    border-radius: 12px;
    border: none;
    cursor: pointer;
    background: linear-gradient(145deg, #7f0000, #c70000);
    color: #fff;
    box-shadow: 
        inset 0 1px 0 rgba(255,255,255,0.1),
        0 6px 15px rgba(100,0,0,0.7);
    transition: all 0.2s ease;
}

button:hover {
    transform: translateY(-3px);
    box-shadow:
        inset 0 1px 0 rgba(255,255,255,0.1),
        0 10px 25px rgba(150,0,0,0.9);
}

button:active {
    transform: translateY(3px);
    box-shadow:
        inset 0 2px 4px rgba(0,0,0,0.6),
        0 4px 10px rgba(100,0,0,0.9);
    background: linear-gradient(145deg, #a60000, #ff0000);
}