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

body {
    background: #0a0a1a;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    overflow: hidden;
}

#game-container {
    position: relative;
    width: 900px;
    height: 700px;
}

#gameCanvas {
    display: block;
    background: radial-gradient(ellipse at center, #1a1a3a 0%, #0a0a1a 100%);
    border: 2px solid #3a3a6a;
    border-radius: 8px;
    box-shadow: 0 0 30px rgba(100, 100, 255, 0.3);
}

#ui-overlay {
    position: absolute;
    top: 10px;
    left: 10px;
    right: 10px;
    display: flex;
    justify-content: space-between;
    color: #fff;
    font-size: 18px;
    text-shadow: 0 0 10px rgba(100, 200, 255, 0.8);
    pointer-events: none;
}

#ui-overlay > div {
    background: rgba(0, 0, 0, 0.5);
    padding: 8px 16px;
    border-radius: 4px;
    border: 1px solid rgba(100, 200, 255, 0.3);
}

.screen {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background: rgba(10, 10, 30, 0.95);
    padding: 40px 60px;
    border-radius: 16px;
    border: 2px solid #4a4a8a;
    text-align: center;
    color: #fff;
    box-shadow: 0 0 50px rgba(100, 100, 255, 0.4);
}

.screen h1 {
    font-size: 36px;
    margin-bottom: 20px;
    text-shadow: 0 0 20px rgba(100, 200, 255, 0.8);
}

.screen p {
    font-size: 18px;
    margin-bottom: 15px;
    color: #aaa;
}

.screen ul {
    text-align: left;
    margin: 20px 0;
    padding-left: 20px;
}

.screen li {
    margin: 10px 0;
    color: #ccc;
    font-size: 14px;
}

.screen button {
    background: linear-gradient(135deg, #4a4aff, #2a2a8a);
    color: #fff;
    border: none;
    padding: 15px 40px;
    font-size: 20px;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    margin-top: 20px;
    text-transform: uppercase;
    letter-spacing: 2px;
}

.screen button:hover {
    background: linear-gradient(135deg, #6a6aff, #4a4aaa);
    transform: scale(1.05);
    box-shadow: 0 0 20px rgba(100, 100, 255, 0.6);
}

.hidden {
    display: none !important;
}

#final-score, #final-wave, #next-wave {
    color: #6af;
    font-weight: bold;
}