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

body {
    font-family: 'Microsoft YaHei', Arial, sans-serif;
    background-color: #000;
    color: #fff;
    overflow: hidden;
}

#game-container {
    position: relative;
    width: 100vw;
    height: 100vh;
    background: linear-gradient(to bottom, #001133, #000000);
}

#game-canvas {
    display: block;
    background-color: transparent;
}

/* UI元素 */
#ui {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 10;
}

#score {
    position: absolute;
    top: 20px;
    left: 20px;
    font-size: 24px;
    font-weight: bold;
}

#level {
    position: absolute;
    top: 20px;
    right: 20px;
    font-size: 24px;
    font-weight: bold;
}

#wave {
    position: absolute;
    top: 60px;
    right: 20px;
    font-size: 24px;
    font-weight: bold;
}

#lives {
    position: absolute;
    top: 60px;
    left: 20px;
    font-size: 20px;
}

#hp-bar {
    position: absolute;
    top: 100px;
    left: 20px;
    width: 200px;
    height: 20px;
    background-color: #333;
    border-radius: 10px;
    overflow: hidden;
}

#hp-fill {
    height: 100%;
    background-color: #00ff00;
    transition: width 0.3s ease;
}

#energy-bar {
    position: absolute;
    top: 140px;
    left: 20px;
    width: 200px;
    height: 20px;
    background-color: #333;
    border-radius: 10px;
    overflow: hidden;
}

#energy-fill {
    height: 100%;
    background-color: #0066ff;
    transition: width 0.3s ease;
}

#game-over {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
    background-color: rgba(0, 0, 0, 0.8);
    padding: 40px;
    border-radius: 10px;
    pointer-events: auto;
    display: none;
}

#game-over h2 {
    font-size: 36px;
    margin-bottom: 20px;
}

#final-score {
    font-size: 24px;
    margin-bottom: 20px;
}

.button {
    padding: 15px 30px;
    font-size: 20px;
    font-weight: bold;
    background-color: #ff6600;
    color: #fff;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    margin: 10px;
    pointer-events: auto;
    transition: background-color 0.3s ease;
}

.button:hover {
    background-color: #ff8800;
}

#start-screen {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.9);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    pointer-events: auto;
}

#start-screen h1 {
    font-size: 48px;
    margin-bottom: 40px;
    color: #ff6600;
}

#difficulty-selector {
    margin-bottom: 30px;
}

.difficulty-btn {
    padding: 10px 20px;
    font-size: 18px;
    margin: 0 10px;
    border: 2px solid #fff;
    background-color: transparent;
    color: #fff;
    border-radius: 5px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.difficulty-btn:hover {
    background-color: #fff;
    color: #000;
}

.difficulty-btn.selected {
    background-color: #ff6600;
    border-color: #ff6600;
    color: #fff;
}

#pause-menu {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
    background-color: rgba(0, 0, 0, 0.8);
    padding: 40px;
    border-radius: 10px;
    pointer-events: auto;
    display: none;
}

#skill-btn {
    position: absolute;
    bottom: 20px;
    right: 20px;
    width: 80px;
    height: 80px;
    border-radius: 50%;
    background-color: rgba(0, 102, 255, 0.8);
    color: #fff;
    border: 2px solid #fff;
    font-size: 24px;
    font-weight: bold;
    cursor: pointer;
    pointer-events: auto;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: all 0.3s ease;
}

#skill-btn:hover {
    background-color: rgba(0, 102, 255, 1);
    transform: scale(1.1);
}

#skill-btn:disabled {
    background-color: rgba(100, 100, 100, 0.5);
    cursor: not-allowed;
    transform: none;
}