body, html {
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
    background: linear-gradient(to bottom, #9EE7F9 0%, #39B4D2 66%, #0087A9 100%);
    font-family: sans-serif;
}

#controls {
    position: absolute;
    top: 20px;
    left: 20px;
    z-index: 100;
    background: rgba(255, 255, 255, 0.8);
    padding: 10px;
    border-radius: 8px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.upload-btn {
    cursor: pointer;
    font-weight: bold;
    color: #006064;
    padding: 8px 16px;
    border: 2px solid #006064;
    border-radius: 4px;
    display: inline-block;
    transition: all 0.2s;
}

.upload-btn:hover {
    background-color: #006064;
    color: white;
}

#aquarium {
    position: relative;
    width: 100%;
    height: 100%;
}

.fish-container {
    position: absolute;
    width: 150px; /* Fixed container size for collision logic ease */
    height: 150px;
    pointer-events: none;
    user-select: none;
}

.fish {
    width: 100%;
    height: 100%;
    object-fit: contain;
    animation: wobble 2s infinite ease-in-out;
}

@keyframes wobble {
    0%, 100% { transform: rotate(0deg); }
    25% { transform: rotate(5deg); }
    75% { transform: rotate(-5deg); }
}

/* Mobile: smaller fish and decorations */
@media (max-width: 600px) {
    .fish-container {
        width: 80px;
        height: 80px;
    }

    .seaweed {
        max-height: 120px !important;
    }
}