body {
    font-family: Arial, Helvetica, sans-serif;
    background: #000000;
    margin: 0;
    padding: 10px;
    min-height: 100vh;
    -webkit-text-size-adjust: 100%;
    -webkit-tap-highlight-color: transparent;
}

.game-container {
    max-width: 600px;
    margin: 0 auto;
    text-align: center;
    padding: 0 5px;
}

h1 {
    color: #ffffff;
    font-size: 2.5em;
    margin-bottom: 10px;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.5);
}

.subtitle {
    color: #cccccc;
    font-size: 1.2em;
    margin-bottom: 30px;
}

.game-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 15px;
    margin: 30px 0;
    padding: 20px;
    background: rgba(255,255,255,0.1);
    border-radius: 20px;
    backdrop-filter: blur(10px);
}

.completed-category {
    grid-column: 1 / -1;
    background: linear-gradient(135deg, #4CAF50, #45a049);
    color: white;
    padding: 20px;
    border-radius: 15px;
    font-weight: bold;
    font-size: 1.1em;
    text-align: center;
    margin-bottom: 10px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.2);
    animation: slideIn 0.5s ease-out;
}

.completed-category .icons {
    font-size: 1.8em;
    margin-top: 10px;
    display: flex;
    justify-content: center;
    gap: 15px;
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.icon-card {
    background: white;
    border: 3px solid #ddd;
    border-radius: 15px;
    padding: 20px;
    font-size: 3em;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
    user-select: none;
}

.icon-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.2);
}

.icon-card.selected {
    border-color: #FFD700;
    border-width: 5px;
    background: #FFF9C4;
    transform: scale(1.1);
    box-shadow: 0 0 20px rgba(255, 215, 0, 0.8);
}

.controls {
    margin: 20px 0;
}

.btn {
    color: white;
    border: none;
    padding: 15px 30px;
    font-size: 1.2em;
    border-radius: 25px;
    cursor: pointer;
    margin: 0 10px;
    transition: all 0.3s ease;
    font-family: inherit;
    font-weight: bold;
}

.btn:hover {
    transform: translateY(-2px);
}

.btn:disabled {
    background: #666 !important;
    cursor: not-allowed;
    transform: none;
}

/* "Make a Group" button - Red */
#groupBtn {
    background: red;
}

#groupBtn:hover:not(:disabled) {
    background: #cc0000;
}

/* "Clear Selection" button - Orange */
#clearBtn {
    background: #FF9800;
}

#clearBtn:hover {
    background: #F57C00;
}

/* "New Game" button - Blue */
.new-game-btn {
    background: blue;
}

.new-game-btn:hover {
    background: #0000cc;
}

.feedback {
    margin: 20px 0;
    font-size: 1.3em;
    font-weight: bold;
    min-height: 30px;
}

.success { color: #4CAF50; }
.error { color: #f44336; }

/* Mobile Responsive Design */
@media (max-width: 768px) {
    body {
        padding: 5px;
    }

    .game-container {
        padding: 0;
    }

    h1 {
        font-size: 1.8em;
        margin-bottom: 5px;
        line-height: 1.2;
    }

    .subtitle {
        font-size: 1em;
        margin-bottom: 15px;
    }

    .game-grid {
        grid-template-columns: repeat(4, 1fr);
        gap: 8px;
        margin: 15px 0;
        padding: 10px;
        border-radius: 15px;
    }

    .icon-card {
        padding: 12px;
        font-size: 2.2em;
        border-radius: 12px;
        border-width: 2px;
        min-height: 60px;
        display: flex;
        align-items: center;
        justify-content: center;
    }

    .icon-card:hover {
        transform: none;
    }

    .icon-card:active {
        transform: scale(0.95);
    }

    .completed-category {
        padding: 15px;
        border-radius: 12px;
        font-size: 1em;
        margin-bottom: 8px;
    }

    .completed-category .icons {
        font-size: 1.5em;
        margin-top: 8px;
        gap: 10px;
    }

    .controls {
        margin: 20px 0;
        display: flex;
        flex-direction: column;
        gap: 20px;
        align-items: center;
    }

    .btn {
        padding: 20px 35px;
        font-size: 1.3em;
        border-radius: 30px;
        margin: 0;
        width: auto;
        min-width: 280px;
        max-width: 90%;
        min-height: 70px;
    }

    .btn:hover {
        transform: none;
    }

    .btn:active {
        transform: scale(0.98);
    }

    .feedback {
        margin: 15px 0;
        font-size: 1.1em;
        min-height: 25px;
        padding: 0 10px;
    }

    .new-game-btn {
        margin-top: 30px;
        min-height: 70px;
    }
}

@media (max-width: 480px) {
    h1 {
        font-size: 1.5em;
    }

    .subtitle {
        font-size: 0.9em;
    }

    .game-grid {
        gap: 6px;
        padding: 8px;
    }

    .icon-card {
        padding: 8px;
        font-size: 1.8em;
        min-height: 50px;
    }

    .btn {
        font-size: 1.2em;
        padding: 18px 30px;
        min-width: 260px;
        min-height: 65px;
    }

    .feedback {
        font-size: 1em;
    }
}

@media (max-width: 360px) {
    .icon-card {
        font-size: 1.6em;
        padding: 6px;
        min-height: 45px;
    }

    .game-grid {
        gap: 4px;
        padding: 6px;
    }

    .btn {
        min-width: 240px;
        font-size: 1.1em;
        min-height: 60px;
    }
}