body {
    margin: 0;
    overflow: hidden;
    background-color: #1a1a2e;
    /* Dark premium background */
    color: white;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
}

#game-container {
    position: relative;
    width: 1024px;
    height: 768px;
    /* Glassmorphism effect */
    background: rgba(255, 255, 255, 0.05);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 16px;
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
}

#connections {
    position: absolute;
    top: 0;
    left: 0;
    pointer-events: none;
    /* Let clicks pass through to nodes */
    z-index: 0;
}

.node {
    position: absolute;
    width: 30px;
    height: 30px;
    border-radius: 50%;
    transform: translate(-50%, -50%);
    /* Center based on coordinate */
    cursor: pointer;
    z-index: 1;
    transition: top 0.3s ease, left 0.3s ease, background-color 0.2s;
    box-shadow: 0 0 5px rgba(0, 0, 0, 0.5);
    border: 2px solid rgba(255, 255, 255, 0.2);
}

.node:hover {
    transform: translate(-50%, -50%) scale(1.1);
    box-shadow: 0 0 15px rgba(255, 255, 255, 0.4);
    z-index: 2;
}

#score-display {
    /* Legacy ID, kept if needed, but overridden below */
}

#combo-display {
    position: absolute;
    top: 20px;
    left: 20px;
    /* Moved to left */
    font-size: 24px;
    font-weight: bold;
    color: #FFD740;
    text-shadow: 0 0 10px rgba(255, 215, 64, 0.5);
    pointer-events: none;
    z-index: 10;
}

/* UI Header */
#ui-header {
    position: absolute;
    top: 20px;
    right: 20px;
    text-align: right;
    z-index: 10;
    pointer-events: none;
    font-family: 'Segoe UI', sans-serif;
}

#level-display,
#moves-display,
#score-display {
    font-size: 24px;
    font-weight: bold;
    margin-bottom: 5px;
    color: white;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.5);
    display: block;
    /* Ensure they stack */
    position: static;
    /* Override legacy absolute */
}

/* Message Overlay */
#message-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.85);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 100;
    backdrop-filter: blur(5px);
    transition: opacity 0.3s;
}

#message-title {
    font-size: 48px;
    margin-bottom: 20px;
    color: #00E676;
    text-transform: uppercase;
    letter-spacing: 2px;
    text-shadow: 0 0 20px rgba(0, 230, 118, 0.4);
}

#message-btn {
    padding: 15px 40px;
    font-size: 24px;
    font-weight: bold;
    background: #448AFF;
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: transform 0.2s, background 0.2s, box-shadow 0.2s;
    box-shadow: 0 4px 15px rgba(68, 138, 255, 0.4);
}

#message-btn:hover {
    transform: scale(1.05);
    background: #2979FF;
    box-shadow: 0 6px 20px rgba(41, 121, 255, 0.6);
}

/* Utility */
.hidden {
    display: none !important;
}