/* 基础样式重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* 页面主体样式 */
body {
    font-family: 'Arial', sans-serif;
    background: linear-gradient(135deg, #0c0c2e 0%, #1a1a3e 50%, #2d1b69 100%);
    overflow: hidden;
    height: 100vh;
    position: relative;
}

/* 星空背景样式 - 增强效果 */
.stars {
    position: absolute;
    width: 100%;
    height: 100%;
    background: transparent;
    z-index: 1;
}

.star {
    position: absolute;
    background: white;
    border-radius: 50%;
    animation: twinkle 2s infinite alternate;
    box-shadow: 0 0 6px rgba(255,255,255,0.8);
}

    .star:nth-child(3n) {
        animation-duration: 3s;
        background: #87CEEB;
    }

    .star:nth-child(5n) {
        animation-duration: 1.5s;
        background: #FFE4B5;
    }

@keyframes twinkle {
    0% {
        opacity: 0.2;
        transform: scale(0.8);
    }

    100% {
        opacity: 0.8;
        transform: scale(1.2);
    }
}

/* 滚动背景 - 增强渐变效果 */
.scrolling-bg {
    position: absolute;
    width: 100%;
    height: 200%;
    background: radial-gradient(circle at 20% 30%, rgba(74, 144, 226, 0.08) 0%, transparent 50%), radial-gradient(circle at 80% 70%, rgba(255, 100, 100, 0.08) 0%, transparent 50%), radial-gradient(circle at 40% 80%, rgba(100, 255, 100, 0.08) 0%, transparent 50%), radial-gradient(circle at 60% 20%, rgba(255, 255, 100, 0.05) 0%, transparent 50%);
    z-index: 1;
    animation: scrollBackground 25s linear infinite;
}

@keyframes scrollBackground {
    0% {
        transform: translateY(-50%);
    }

    100% {
        transform: translateY(0%);
    }
}

/* 游戏容器 */
.game-container {
    position: relative;
    width: 100vw;
    height: 100vh;
    overflow: hidden;
    z-index: 2;
}

.game-canvas {
    width: 100%;
    height: 100%;
    display: block;
    background: transparent;
}

/* UI覆盖层 */
.ui-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 3;
}

/* 分数面板 - 优化设计 */
.score-board {
    position: absolute;
    top: 20px;
    left: 20px;
    color: white;
    font-size: 18px;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.8);
    pointer-events: auto;
    padding: 15px;
    border-radius: 15px;
    border: 1px solid rgba(255,255,255,0.2);
}

.score-item {
    margin: 8px 0;
    display: flex;
    align-items: center;
    gap: 10px;
    transition: all 0.3s ease;
}

    .score-item:hover {
        transform: translateX(5px);
    }

.crown-display {
    color: #ffd700;
    font-size: 22px;
    text-shadow: 0 0 15px #ffd700;
    animation: crownGlow 2s ease-in-out infinite alternate;
}

@keyframes crownGlow {
    0% {
        text-shadow: 0 0 15px #ffd700;
    }

    100% {
        text-shadow: 0 0 25px #ffd700, 0 0 35px #ffd700;
    }
}

.difficulty-display {
    background: rgba(255,255,255,0.15);
    padding: 8px 12px;
    border-radius: 20px;
    backdrop-filter: blur(8px);
    border: 1px solid rgba(255,255,255,0.3);
    margin-top: 10px;
    transition: all 0.3s ease;
}

.power-display {
    background: rgba(255,165,0,0.25);
    padding: 8px 12px;
    border-radius: 20px;
    backdrop-filter: blur(8px);
    border: 1px solid rgba(255,165,0,0.6);
    margin-top: 5px;
    color: #ffa500;
    box-shadow: 0 0 10px rgba(255,165,0,0.3);
}

.shield-display {
    background: rgba(0,191,255,0.25);
    padding: 8px 12px;
    border-radius: 20px;
    backdrop-filter: blur(8px);
    border: 1px solid rgba(0,191,255,0.6);
    margin-top: 5px;
    color: #00bfff;
    box-shadow: 0 0 10px rgba(0,191,255,0.3);
}

.auto-fire-display {
    background: rgba(255,255,255,0.15);
    padding: 8px 12px;
    border-radius: 20px;
    backdrop-filter: blur(8px);
    border: 1px solid rgba(255,255,255,0.4);
    margin-top: 5px;
    color: #ffffff;
    box-shadow: 0 0 10px rgba(255,255,255,0.2);
}

.boss-count-display {
    background: rgba(255,0,0,0.25);
    padding: 8px 12px;
    border-radius: 20px;
    backdrop-filter: blur(8px);
    border: 1px solid rgba(255,0,0,0.6);
    margin-top: 5px;
    color: #ff4444;
    box-shadow: 0 0 10px rgba(255,0,0,0.3);
}

/* 血条系统 - 优化设计 */
.health-bar {
    position: absolute;
    top: 20px;
    right: 20px;
    width: 220px;
    height: 25px;
    background: rgba(0,0,0,0.4);
    border: 2px solid rgba(255,255,255,0.6);
    border-radius: 15px;
    overflow: hidden;
    backdrop-filter: blur(10px);
    box-shadow: 0 4px 15px rgba(0,0,0,0.3);
}

.health-fill {
    height: 100%;
    background: linear-gradient(90deg, #ff4444, #ffaa44, #44ff44);
    transition: width 0.3s ease;
    width: 100%;
    box-shadow: inset 0 2px 4px rgba(255,255,255,0.3);
}

/* 双人模式血条 */
.health-bar-dual {
    position: absolute;
    top: 20px;
    right: 20px;
    width: 220px;
    height: 60px;
    background: rgba(0,0,0,0.4);
    border: 2px solid rgba(255,255,255,0.6);
    border-radius: 15px;
    overflow: hidden;
    display: none;
    backdrop-filter: blur(10px);
    box-shadow: 0 4px 15px rgba(0,0,0,0.3);
    padding: 5px;
}

.health-bar-p1, .health-bar-p2 {
    width: 100%;
    height: 20px;
    background: rgba(255,255,255,0.2);
    border-radius: 8px;
    overflow: hidden;
    margin: 2px 0;
    border: 1px solid rgba(255,255,255,0.3);
}

.health-fill-p1, .health-fill-p2 {
    height: 100%;
    background: linear-gradient(90deg, #ff4444, #ffaa44, #44ff44);
    transition: width 0.3s ease;
    width: 100%;
    box-shadow: inset 0 2px 4px rgba(255,255,255,0.3);
}

.player-label {
    position: absolute;
    left: -60px;
    top: 50%;
    transform: translateY(-50%);
    color: white;
    font-size: 12px;
    font-weight: bold;
    text-shadow: 1px 1px 2px rgba(0,0,0,0.8);
}

/* 炸弹系统 - 优化设计 */
.bomb-counter {
    position: absolute;
    top: 95px;
    right: 20px;
    color: white;
    font-size: 16px;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.8);
    background: rgba(255,100,100,0.3);
    padding: 8px 15px;
    border-radius: 15px;
    border: 1px solid rgba(255,100,100,0.6);
    backdrop-filter: blur(10px);
    box-shadow: 0 4px 15px rgba(255,100,100,0.2);
}

.bomb-cooldown {
    position: absolute;
    top: 145px;
    right: 20px;
    color: #ff6666;
    font-size: 16px;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.8);
    background: rgba(255,100,100,0.4);
    padding: 8px 15px;
    border-radius: 15px;
    border: 1px solid rgba(255,100,100,0.8);
    display: none;
    backdrop-filter: blur(10px);
    box-shadow: 0 4px 15px rgba(255,100,100,0.3);
}

/* 暂停按钮 - 优化设计 */
.pause-btn {
    position: absolute;
    top: 20px;
    left: 50%;
    transform: translateX(-50%);
    background: rgba(255,255,255,0.25);
    border: 2px solid rgba(255,255,255,0.6);
    color: white;
    width: 55px;
    height: 55px;
    border-radius: 50%;
    font-size: 20px;
    cursor: pointer;
    transition: all 0.3s ease;
    backdrop-filter: blur(15px);
    pointer-events: auto;
    box-shadow: 0 4px 15px rgba(255,255,255,0.2);
}

    .pause-btn:hover {
        background: rgba(255,255,255,0.4);
        transform: translateX(-50%) scale(1.1);
        box-shadow: 0 6px 20px rgba(255,255,255,0.3);
    }

/* Boss血条 - 优化设计 */
.boss-health-bar {
    position: absolute;
    top: 70px;
    left: 50%;
    transform: translateX(-50%);
    width: 350px;
    height: 30px;
    background: rgba(0,0,0,0.5);
    border: 3px solid #ff0000;
    border-radius: 20px;
    overflow: hidden;
    display: none;
    backdrop-filter: blur(10px);
    box-shadow: 0 4px 20px rgba(255,0,0,0.4);
}

.boss-health-fill {
    height: 100%;
    background: linear-gradient(90deg, #ff0000, #ff6600, #ffaa00);
    transition: width 0.3s ease;
    width: 100%;
    box-shadow: inset 0 2px 4px rgba(255,255,255,0.3);
}

/* Boss警告 - 增强效果 */
.boss-warning {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: #ff0000;
    font-size: 3em;
    font-weight: bold;
    text-shadow: 0 0 30px #ff0000, 0 0 60px #ff0000;
    animation: bossWarning 2s ease-in-out;
    z-index: 15;
    pointer-events: none;
    background: rgba(0, 0, 0, 0.9);
    padding: 40px 60px;
    border-radius: 25px;
    border: 4px solid #ff0000;
    backdrop-filter: blur(15px);
    text-align: center;
    min-width: 450px;
    box-shadow: 0 0 50px rgba(255,0,0,0.5), inset 0 0 30px rgba(255,0,0,0.1);
}

    .boss-warning .boss-subtitle {
        font-size: 0.4em;
        color: #ffaa00;
        margin-top: 15px;
        text-shadow: 0 0 15px #ffaa00, 0 0 30px #ffaa00;
        font-weight: normal;
    }

@keyframes bossWarning {
    0% {
        opacity: 0;
        transform: translate(-50%, -50%) scale(0.5);
    }

    20% {
        opacity: 1;
        transform: translate(-50%, -50%) scale(1.1);
    }

    80% {
        opacity: 1;
        transform: translate(-50%, -50%) scale(1);
    }

    100% {
        opacity: 0;
        transform: translate(-50%, -50%) scale(0.8);
    }
}

/* 游戏界面 - 优化背景 */
.intro-screen, .game-over-screen, .difficulty-screen, .pause-screen {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: radial-gradient(circle at 30% 20%, rgba(74, 144, 226, 0.1) 0%, transparent 50%), radial-gradient(circle at 70% 80%, rgba(255, 100, 100, 0.1) 0%, transparent 50%), rgba(0,0,0,0.92);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    color: white;
    text-align: center;
    z-index: 10;
    pointer-events: auto;
    backdrop-filter: blur(5px);
}

.pause-screen {
    display: none;
}

.intro-screen h1 {
    font-size: 3.5em;
    margin-bottom: 40px;
    text-shadow: 0 0 30px #4a90e2, 0 0 60px #4a90e2;
    animation: glow 2s ease-in-out infinite alternate;
    background: linear-gradient(45deg, #4a90e2, #87CEEB, #4a90e2);
    background-size: 200% 200%;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: glow 2s ease-in-out infinite alternate, gradientShift 3s ease-in-out infinite;
}

@keyframes glow {
    from {
        text-shadow: 0 0 30px #4a90e2, 0 0 60px #4a90e2;
        filter: brightness(1);
    }

    to {
        text-shadow: 0 0 40px #4a90e2, 0 0 80px #4a90e2, 0 0 120px #4a90e2;
        filter: brightness(1.2);
    }
}

@keyframes gradientShift {
    0% {
        background-position: 0% 50%;
    }

    50% {
        background-position: 100% 50%;
    }

    100% {
        background-position: 0% 50%;
    }
}

/* 难度选择界面布局 - 优化设计 */
.difficulty-screen {
    display: grid;
    grid-template-columns: 1fr 350px;
    gap: 50px;
    padding: 50px;
    align-items: start;
    justify-items: center;
    z-index: 10;
}

.difficulty-main {
    display: flex;
    flex-direction: column;
    align-items: center;
    max-width: 900px;
}

    .difficulty-main h1 {
        font-size: 3.5em;
        margin-bottom: 40px;
        text-shadow: 0 0 30px #4a90e2, 0 0 60px #4a90e2;
        animation: glow 2s ease-in-out infinite alternate;
        background: linear-gradient(45deg, #4a90e2, #87CEEB, #4a90e2);
        background-size: 200% 200%;
        -webkit-background-clip: text;
        -webkit-text-fill-color: transparent;
        background-clip: text;
        animation: glow 2s ease-in-out infinite alternate, gradientShift 3s ease-in-out infinite;
    }

.difficulty-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 25px;
    margin: 30px 0;
    width: 100%;
}

.difficulty-card {
    background: rgba(255,255,255,0.12);
    padding: 25px;
    border-radius: 20px;
    backdrop-filter: blur(15px);
    border: 2px solid rgba(255,255,255,0.25);
    cursor: pointer;
    transition: all 0.4s ease;
    text-align: center;
    position: relative;
    overflow: hidden;
}

    .difficulty-card::before {
        content: '';
        position: absolute;
        top: 0;
        left: -100%;
        width: 100%;
        height: 100%;
        background: linear-gradient(90deg, transparent, rgba(255,255,255,0.1), transparent);
        transition: left 0.5s ease;
    }

    .difficulty-card:hover::before {
        left: 100%;
    }

    .difficulty-card:hover {
        border-color: #4a90e2;
        transform: translateY(-8px);
        box-shadow: 0 15px 35px rgba(74, 144, 226, 0.4);
        background: rgba(255,255,255,0.18);
    }

    .difficulty-card.selected {
        border-color: #4a90e2;
        background: rgba(74, 144, 226, 0.25);
        box-shadow: 0 10px 30px rgba(74, 144, 226, 0.3);
    }

    .difficulty-card h4 {
        color: #4a90e2;
        margin-bottom: 15px;
        font-size: 1.4em;
        text-shadow: 0 0 10px currentColor;
    }

.difficulty-easy h4 {
    color: #44ff44;
    text-shadow: 0 0 15px #44ff44;
}

.difficulty-normal h4 {
    color: #ffaa44;
    text-shadow: 0 0 15px #ffaa44;
}

.difficulty-hard h4 {
    color: #ff4444;
    text-shadow: 0 0 15px #ff4444;
}

.difficulty-nightmare h4 {
    color: #ff00ff;
    text-shadow: 0 0 15px #ff00ff;
}

.difficulty-fun h4 {
    color: #00ffff;
    text-shadow: 0 0 15px #00ffff;
}

.difficulty-dual h4 {
    color: #ff8800;
    text-shadow: 0 0 15px #ff8800;
}

/* 右侧历史最高分区域 - 优化设计 */
.high-score-sidebar {
    background: rgba(255,215,0,0.15);
    padding: 35px 25px;
    border-radius: 25px;
    backdrop-filter: blur(20px);
    border: 2px solid rgba(255,215,0,0.4);
    width: fit-content;
    height: fit-content;
    position: absolute;
    top: 100px;
    right: 80px;
    overflow: hidden;
    box-shadow: 0 10px 30px rgba(255,215,0,0.2);
}

    .high-score-sidebar::before {
        content: '';
        position: absolute;
        top: 0;
        left: 0;
        right: 0;
        bottom: 0;
        background: radial-gradient(circle at 20% 20%, rgba(255,215,0,0.15) 0%, transparent 50%), radial-gradient(circle at 80% 80%, rgba(255,255,255,0.08) 0%, transparent 50%);
        pointer-events: none;
    }

    .high-score-sidebar h3 {
        color: #ffd700;
        margin-bottom: 25px;
        text-shadow: 0 0 20px #ffd700, 0 0 40px #ffd700;
        font-size: 1.6em;
        text-align: center;
        position: relative;
        z-index: 1;
    }

.high-score-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin: 18px 0;
    padding: 12px 18px;
    background: rgba(255,215,0,0.15);
    border-radius: 15px;
    border: 1px solid rgba(255,215,0,0.4);
    color: #ffd700;
    position: relative;
    z-index: 1;
    transition: all 0.4s ease;
    backdrop-filter: blur(5px);
}

    .high-score-item:hover {
        background: rgba(255,215,0,0.25);
        transform: translateX(8px);
        box-shadow: 0 5px 15px rgba(255,215,0,0.3);
    }

    .high-score-item .difficulty-name {
        font-weight: bold;
        text-shadow: 0 0 10px currentColor;
    }

    .high-score-item .score-value {
        font-family: 'Courier New', monospace;
        font-weight: bold;
        font-size: 1.1em;
    }

/* 控制说明 - 优化设计 */
.controls {
    background: rgba(255,255,255,0.12);
    padding: 25px;
    border-radius: 20px;
    margin: 25px;
    backdrop-filter: blur(15px);
    border: 1px solid rgba(255,255,255,0.25);
    max-width: 550px;
    text-align: left;
    box-shadow: 0 8px 25px rgba(0,0,0,0.2);
}

    .controls h3 {
        margin-bottom: 20px;
        color: #4a90e2;
        text-shadow: 0 0 15px #4a90e2;
        font-size: 1.3em;
    }

.control-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin: 12px 0;
    padding: 8px 0;
    border-bottom: 1px solid rgba(255,255,255,0.1);
    transition: all 0.3s ease;
}

    .control-item:hover {
        padding-left: 10px;
        color: #87CEEB;
    }

/* 游戏介绍页面滚动 */
.intro-screen {
    overflow-y: auto;
    padding: 30px;
    justify-content: flex-start;
    align-items: center;
}

.intro-content {
    max-width: 900px;
    width: 100%;
    margin: 0 auto;
    align-items: center;
}

    .intro-content h1 {
        position: sticky;
        top: 0;
        padding: 25px 0;
        z-index: 5;
        margin-bottom: 30px;
        backdrop-filter: blur(10px);
    }

.intro-section {
    margin-bottom: 40px;
    width: 100%;
    display: flex;
    justify-content: center;
}

/* 按钮样式 - 优化设计 */
.btn {
    background: linear-gradient(45deg, #4a90e2, #357abd);
    border: none;
    color: white;
    padding: 18px 35px;
    font-size: 18px;
    border-radius: 30px;
    cursor: pointer;
    transition: all 0.4s ease;
    box-shadow: 0 6px 20px rgba(74, 144, 226, 0.4);
    margin: 12px;
    position: relative;
    z-index: 100;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1px;
    overflow: hidden;
}

    .btn::before {
        content: '';
        position: absolute;
        top: 0;
        left: -100%;
        width: 100%;
        height: 100%;
        background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
        transition: left 0.5s ease;
    }

    .btn:hover::before {
        left: 100%;
    }

    .btn:hover {
        transform: translateY(-3px);
        box-shadow: 0 10px 30px rgba(74, 144, 226, 0.6);
        background: linear-gradient(45deg, #5ba0f2, #4a90e2);
    }

    .btn:disabled {
        opacity: 0.5;
        cursor: not-allowed;
        transform: none;
    }

.btn-danger {
    background: linear-gradient(45deg, #e74c3c, #c0392b);
    box-shadow: 0 6px 20px rgba(231, 76, 60, 0.4);
}

    .btn-danger:hover {
        box-shadow: 0 10px 30px rgba(231, 76, 60, 0.6);
        background: linear-gradient(45deg, #f75c4c, #e74c3c);
    }

.btn-warning {
    background: linear-gradient(45deg, #f39c12, #e67e22);
    box-shadow: 0 6px 20px rgba(243, 156, 18, 0.4);
}

    .btn-warning:hover {
        box-shadow: 0 10px 30px rgba(243, 156, 18, 0.6);
        background: linear-gradient(45deg, #ffac22, #f39c12);
    }

/* 移动端控制 - 优化设计 */
.mobile-controls {
    position: absolute;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    display: none;
    pointer-events: auto;
}

.mobile-btn {
    background: rgba(255,255,255,0.25);
    border: 2px solid rgba(255,255,255,0.6);
    color: white;
    width: 65px;
    height: 65px;
    border-radius: 50%;
    margin: 8px;
    font-size: 22px;
    cursor: pointer;
    transition: all 0.3s ease;
    backdrop-filter: blur(15px);
    box-shadow: 0 4px 15px rgba(255,255,255,0.2);
}

    .mobile-btn:active {
        background: rgba(255,255,255,0.4);
        transform: scale(0.95);
    }

    .mobile-btn:disabled {
        opacity: 0.5;
        cursor: not-allowed;
        transform: none;
    }

.bomb-btn {
    background: rgba(255, 165, 0, 0.35);
    border-color: rgba(255, 165, 0, 0.8);
    width: 75px;
    height: 75px;
    font-size: 22px;
    box-shadow: 0 4px 15px rgba(255, 165, 0, 0.3);
}

    .bomb-btn:disabled {
        background: rgba(100, 100, 100, 0.3);
        border-color: rgba(100, 100, 100, 0.7);
    }

/* 暂停界面特殊样式 */
.pause-screen h1 {
    font-size: 3.5em;
    margin-bottom: 40px;
    text-shadow: 0 0 30px #4a90e2, 0 0 60px #4a90e2;
    animation: glow 2s ease-in-out infinite alternate;
    background: linear-gradient(45deg, #4a90e2, #87CEEB, #4a90e2);
    background-size: 200% 200%;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: glow 2s ease-in-out infinite alternate, gradientShift 3s ease-in-out infinite;
}

.pause-screen .controls {
    margin: 25px 0;
    text-align: center;
}

    .pause-screen .controls p {
        font-size: 16px;
        line-height: 1.8;
        color: #cccccc;
    }

.pause-buttons {
    display: flex;
    gap: 25px;
    margin-top: 40px;
    flex-wrap: wrap;
    justify-content: center;
}

/* 特效样式 - 增强效果 */
.explosion {
    position: absolute;
    pointer-events: none;
    z-index: 5;
    border-radius: 50%;
    box-shadow: 0 0 20px currentColor;
}

.powerup {
    position: absolute;
    animation: powerupFloat 2s ease-in-out infinite alternate;
    filter: drop-shadow(0 0 10px currentColor);
}

@keyframes powerupFloat {
    0% {
        transform: translateY(0px) rotate(0deg);
    }

    100% {
        transform: translateY(-15px) rotate(10deg);
    }
}

.bomb-explosion {
    position: absolute;
    pointer-events: none;
    z-index: 8;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(255,255,255,0.9) 0%, rgba(255,165,0,0.7) 30%, rgba(255,0,0,0.5) 60%, transparent 100%);
    animation: bombBlast 0.6s ease-out;
    box-shadow: 0 0 50px rgba(255,165,0,0.8);
}

@keyframes bombBlast {
    0% {
        transform: scale(0);
        opacity: 1;
    }

    50% {
        opacity: 0.8;
    }

    100% {
        transform: scale(12);
        opacity: 0;
    }
}

/* 星空动画增强 */
.menu-stars {
    position: absolute;
    width: 100%;
    height: 100%;
    overflow: hidden;
    z-index: -1;
}

.shooting-star {
    position: absolute;
    width: 3px;
    height: 3px;
    background: white;
    border-radius: 50%;
    animation: shootingStar 4s linear infinite;
    box-shadow: 0 0 10px white;
}

@keyframes shootingStar {
    0% {
        transform: translateX(-100px) translateY(-100px);
        opacity: 0;
    }

    10% {
        opacity: 1;
    }

    90% {
        opacity: 1;
    }

    100% {
        transform: translateX(100vw) translateY(100vh);
        opacity: 0;
    }
}

.nebula {
    position: absolute;
    border-radius: 50%;
    filter: blur(50px);
    animation: nebulaPulse 10s ease-in-out infinite alternate;
}

@keyframes nebulaPulse {
    0% {
        transform: scale(1) rotate(0deg);
        opacity: 0.3;
    }

    100% {
        transform: scale(1.3) rotate(180deg);
        opacity: 0.7;
    }
}

/* 黑洞样式 - 增强效果 */
.blackhole {
    position: absolute;
    pointer-events: none;
    z-index: 6;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(0,0,0,0.95) 0%, rgba(75,0,130,0.7) 30%, rgba(138,43,226,0.4) 60%, transparent 100%);
    animation: blackholeRotate 4s linear infinite;
    box-shadow: 0 0 30px rgba(138,43,226,0.6);
}

@keyframes blackholeRotate {
    0% {
        transform: rotate(0deg);
    }

    100% {
        transform: rotate(360deg);
    }
}

/* 陨石样式 - 增强效果 */
.meteor {
    position: absolute;
    background: radial-gradient(circle at 30% 30%, #8B4513, #654321, #2F1B14);
    border-radius: 50%;
    animation: meteorSpin 2s linear infinite;
    box-shadow: 0 0 20px rgba(139, 69, 19, 0.8), inset -8px -8px 15px rgba(0,0,0,0.6);
}

@keyframes meteorSpin {
    0% {
        transform: rotate(0deg);
    }

    100% {
        transform: rotate(360deg);
    }
}

/* 响应式设计 */
@media (max-width: 768px) {
    .difficulty-screen {
        grid-template-columns: 1fr;
        gap: 25px;
        padding: 25px;
    }

    .difficulty-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }

    .high-score-sidebar {
        order: -1;
        margin-bottom: 25px;
    }

    .mobile-controls {
        display: flex;
        flex-wrap: wrap;
        justify-content: center;
        align-items: center;
    }

    .score-board {
        font-size: 14px;
        top: 15px;
        left: 15px;
        padding: 12px;
    }

    .health-bar {
        width: 140px;
        top: 15px;
        right: 15px;
    }

    .bomb-counter {
        top: 45px;
        right: 15px;
        font-size: 14px;
    }

    .bomb-cooldown {
        top: 75px;
        right: 15px;
        font-size: 12px;
    }

    .pause-btn {
        top: 15px;
        width: 45px;
        height: 45px;
        font-size: 18px;
    }

    .boss-health-bar {
        width: 280px;
        top: 65px;
    }

    .intro-screen h1, .difficulty-main h1, .pause-screen h1 {
        font-size: 2.5em;
    }

    .controls {
        margin: 15px;
        padding: 20px;
    }

    .pause-buttons {
        flex-direction: column;
        align-items: center;
        gap: 20px;
    }

    .btn {
        width: 280px;
        text-align: center;
    }

    .boss-warning {
        font-size: 2.2em;
        min-width: 320px;
        padding: 25px 35px;
    }
}