/* Lesson 9 - Subtract by crossing out */

.cross-container {
    display: flex;
    flex-wrap: wrap;
    gap: 20px;
    justify-content: center;
    margin: 30px 0;
    padding: 20px;
    background-color: #f9f9f9;
    border-radius: 15px;
    border: 3px dashed #ccc;
    position: relative;
    transition: all 0.4s;
}

.cross-container.completed {
    border-color: #34c759;
    background-color: #f0fdf4;
}

.crossable-item {
    font-size: 4.5rem;
    cursor: pointer;
    position: relative;
    user-select: none;
    transition: transform 0.2s, opacity 0.3s;
    -webkit-tap-highlight-color: transparent;
}

.crossable-item:hover {
    transform: scale(1.1);
}

.crossable-item.crossed {
    opacity: 0.4;
}

.crossable-item.crossed::after {
    content: "❌";
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 4.5rem;
    z-index: 2;
    opacity: 1;
    pointer-events: none;
}

.eq-group-locked {
    opacity: 0.3;
    pointer-events: none;
    transition: opacity 0.5s;
    filter: grayscale(100%);
}

.eq-group-unlocked {
    opacity: 1;
    pointer-events: auto;
    filter: none;
}

.lock-msg {
    text-align: center;
    color: #ff9500;
    font-weight: bold;
    font-size: 1.2rem;
    margin-top: -10px;
    margin-bottom: 20px;
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0% { opacity: 0.6; }
    50% { opacity: 1; }
    100% { opacity: 0.6; }
}