body {
    font-family: 'Courier New', Courier, monospace;
    background-color: #000;
    color: #fff;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    overflow: hidden; /* Prevent scrollbars */
}

#game-container {
    width: 90%;
    max-width: 800px;
    border: 2px solid #fff;
    padding: 20px;
    position: relative;
    box-shadow: 0 0 15px #0f0;
}

#ui-container {
    display: flex;
    justify-content: space-between;
    align-items: center; /* Align items vertically */
    margin-bottom: 10px;
    font-size: 1.5em;
}

#level-up-message {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 3em;
    color: #ffd700; /* Gold color */
    text-shadow: 2px 2px 5px #000;
    z-index: 20;
}

#game-area {
    height: 500px;
    position: relative;
    overflow: hidden;
    border: 1px solid #333;
}

#ufo {
    position: absolute;
    top: 10px; /* Appear near the top */
    color: #ff0000; /* Bright red */
    font-size: 1.3em;
    font-weight: bold;
    white-space: nowrap;
    padding: 5px 10px;
    background-color: #333;
    border: 1px solid #ff0000;
    z-index: 10;
    transition: left 10s linear; /* Slow, steady movement */
}

.hidden {
    display: none;
}

.invader {
    position: absolute;
    color: #0f0; /* Classic green */
    font-size: 1.2em;
    white-space: nowrap; /* Prevent word wrapping */
    transition: transform 0.5s ease-out; /* Smooth movement */
}

#input-box {
    width: 100%;
    padding: 10px;
    margin-top: 10px;
    box-sizing: border-box;
    background-color: #222;
    border: 2px solid #fff;
    color: #fff;
    font-size: 1.2em;
    text-align: center;
}

#input-box:focus {
    outline: none;
    border-color: #0f0;
    box-shadow: 0 0 10px #0f0;
}