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

body {
    font-family: 'Courier New', monospace;
    background: #0a0a1a;
    color: #fff;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow: hidden;
}

#game {
    width: 100%;
    max-width: 480px;
    height: 640px;
    background: #0a0a1a;
    border: 4px solid #00ff88;
    border-radius: 8px;
    position: relative;
    overflow: hidden;
}

.screen {
    display: none;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    width: 100%;
    height: 100%;
}

.screen.active {
    display: flex;
}

/* Title Screen */
#title-screen {
    background: linear-gradient(180deg, #0a0a1a 0%, #1a1a3a 100%);
    text-align: center;
}

#title-screen h1 {
    font-size: 2.5em;
    color: #00ff88;
    text-shadow: 0 0 20px #00ff88, 0 0 40px #00ff88;
    margin-bottom: 10px;
    letter-spacing: 4px;
}

.subtitle {
    color: #888;
    margin-bottom: 40px;
    font-size: 1em;
}

#start-btn, #restart-btn {
    background: #00ff88;
    color: #0a0a1a;
    border: none;
    padding: 15px 40px;
    font-size: 1.2em;
    font-family: 'Courier New', monospace;
    cursor: pointer;
    border-radius: 4px;
    font-weight: bold;
    transition: all 0.2s;
}

#start-btn:hover, #restart-btn:hover {
    background: #00cc6a;
    transform: scale(1.05);
    box-shadow: 0 0 20px #00ff88;
}

.controls-hint {
    margin-top: 40px;
    color: #666;
    font-size: 0.9em;
    line-height: 1.8;
}

/* Game Screen */
#game-screen {
    padding: 0;
}

#game-canvas {
    width: 100%;
    height: 100%;
    display: block;
    image-rendering: pixelated;
}

#hud {
    position: absolute;
    top: 10px;
    left: 10px;
    right: 10px;
    display: flex;
    justify-content: space-between;
    font-size: 0.9em;
    color: #00ff88;
    text-shadow: 0 0 10px #00ff88;
    pointer-events: none;
}

#height-display {
    position: absolute;
    bottom: 10px;
    right: 10px;
    font-size: 1em;
    color: #00ff88;
    text-shadow: 0 0 10px #00ff88;
    pointer-events: none;
}

/* Game Over Screen */
#gameover-screen {
    background: linear-gradient(180deg, #0a0a1a 0%, #2a1a1a 100%);
    text-align: center;
}

#gameover-screen h2 {
    font-size: 2em;
    color: #ff4444;
    text-shadow: 0 0 20px #ff4444;
    margin-bottom: 30px;
}

#final-score, #final-height, #final-enemies {
    font-size: 1.2em;
    margin: 10px 0;
    color: #00ff88;
}

#restart-btn {
    margin-top: 30px;
}