* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Courier New', monospace;
    background-color: #000;
    color: #0f0;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    overflow: hidden;
}

#gameContainer {
    position: relative;
    border: 2px solid #0f0;
    box-shadow: 0 0 20px #0f0;
}

#gameCanvas {
    background-color: #000;
    display: block;
}

.screen {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    background-color: rgba(0, 0, 0, 0.9);
    text-align: center;
    z-index: 10;
}

.hidden {
    display: none !important;
}

h1 {
    font-size: 3rem;
    margin-bottom: 20px;
    text-shadow: 0 0 10px #0f0;
    letter-spacing: 3px;
}

h3 {
    margin: 20px 0 10px 0;
    font-size: 1.2rem;
}

p {
    margin: 5px 0;
    font-size: 1.1rem;
    max-width: 80%;
}

button {
    background-color: #000;
    color: #0f0;
    border: 2px solid #0f0;
    padding: 15px 30px;
    margin: 20px 0;
    font-family: 'Courier New', monospace;
    font-size: 1.2rem;
    cursor: pointer;
    transition: all 0.3s;
    text-transform: uppercase;
    letter-spacing: 2px;
}

button:hover {
    background-color: #0f0;
    color: #000;
    box-shadow: 0 0 15px #0f0;
}

#instructions {
    margin-top: 30px;
    padding: 20px;
    border: 1px solid #0f0;
}

#gameUI {
    position: absolute;
    top: 10px;
    left: 10px;
    display: flex;
    flex-direction: column;
    gap: 10px;
    font-size: 1.2rem;
    text-shadow: 0 0 5px #0f0;
}

#score, #health, #level, #ammo {
    background-color: rgba(0, 0, 0, 0.7);
    padding: 5px 10px;
    border: 1px solid #0f0;
}