* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    background-color: #f0f8ff;
    width: 100%;
    height: 100dvh;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    user-select: none;
    -webkit-user-select: none;
    touch-action: none;
}

.hub-grid {
    display: flex;
    flex-wrap: wrap;
    gap: 30px;
    justify-content: center;
    align-items: center;
    padding: 40px;
    width: 100%;
    max-width: 800px;
}

.hub-card {
    width: 160px;
    height: 160px;
    background: white;
    border-radius: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 90px;
    text-decoration: none;
    box-shadow: 0 15px 35px rgba(0,0,0,0.08);
    transition: transform 0.2s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    border: 6px solid #fff;
    -webkit-tap-highlight-color: transparent;
}

.hub-card:active {
    transform: scale(0.9);
}

.hub-card.balloon { 
    border-color: #ff9aa2; 
    background-color: #fff0f1;
}
.hub-card.xylophone { 
    border-color: #fff9c4; 
    background-color: #fffdf0;
}
.hub-card.apple { 
    border-color: #a5d6a7; 
    background-color: #f1f8f1;
}

@media (max-width: 500px) {
    .hub-card {
        width: 130px;
        height: 130px;
        font-size: 70px;
    }
    .hub-grid { gap: 20px; }
}