body {
    margin: 0;
    padding: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background: url('assets/images/big background.png') no-repeat center center fixed;
    font-family: 'Arial', sans-serif;
    overflow: hidden;
    position: relative;
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
}

#game-container {
    position: relative;
    box-shadow: 0 0 30px rgba(255, 215, 0, 0.7), 0 0 50px rgba(255, 255, 255, 0.3);
    border-radius: 20px;
    overflow: hidden;
    background: rgba(0, 0, 0, 0.4);
    backdrop-filter: blur(10px);
    border: 3px solid rgba(255, 215, 0, 0.5);
    z-index: 1;
    padding: 10px;
    animation: containerGlow 3s ease infinite;
}

@keyframes containerGlow {
    0% { box-shadow: 0 0 30px rgba(255, 215, 0, 0.7), 0 0 50px rgba(255, 255, 255, 0.3); }
    50% { box-shadow: 0 0 40px rgba(255, 215, 0, 0.9), 0 0 60px rgba(255, 255, 255, 0.5); }
    100% { box-shadow: 0 0 30px rgba(255, 215, 0, 0.7), 0 0 50px rgba(255, 255, 255, 0.3); }
}

#gameCanvas {
    border: 5px solid rgba(255, 215, 0, 0.5);
    border-radius: 15px;
    background: transparent;
    box-shadow: inset 0 0 20px rgba(255, 215, 0, 0.3), 0 0 20px rgba(255, 215, 0, 0.5);
}

#canvas-background {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: url('assets/images/container background1.png') no-repeat center center;
    background-size: cover;
    z-index: -1;
    transition: background-image 1s ease-in-out;
    border-radius: 15px;
    opacity: 0.6;
}

#score {
    position: absolute;
    top: 20px;
    left: 20px;
    color: #FFD700;
    font-size: 32px;
    font-weight: bold;
    text-shadow: 3px 3px 6px rgba(0, 0, 0, 0.8), 0 0 10px rgba(255, 215, 0, 0.8);
    background: linear-gradient(145deg, rgba(0, 0, 0, 0.6), rgba(0, 0, 0, 0.4));
    padding: 15px 25px;
    border-radius: 15px;
    border: 2px solid rgba(255, 215, 0, 0.5);
    box-shadow: 0 0 15px rgba(255, 215, 0, 0.5);
    animation: scoreGlow 2s ease infinite;
    z-index: 2;
    display: flex;
    align-items: center;
    justify-content: center;
    /* background-image: url('assets/images/gold_texture.jpg'); */ /* Removed due to missing file */
    background-size: cover;
    background-position: center;
    color: #FFF;
    text-shadow: 3px 3px 6px rgba(0, 0, 0, 0.8), 0 0 10px rgba(255, 215, 0, 0.8), 0 0 20px rgba(255, 215, 0, 0.6);
}

@keyframes scoreGlow {
    0% { text-shadow: 3px 3px 6px rgba(0, 0, 0, 0.8), 0 0 10px rgba(255, 215, 0, 0.8); }
    50% { text-shadow: 3px 3px 6px rgba(0, 0, 0, 0.8), 0 0 20px rgba(255, 215, 0, 0.9), 0 0 30px rgba(255, 215, 0, 0.6); }
    100% { text-shadow: 3px 3px 6px rgba(0, 0, 0, 0.8), 0 0 10px rgba(255, 215, 0, 0.8); }
}

/* 添加游戏标题 */
#game-title {
    position: absolute;
    top: 20px;
    right: 20px;
    color: #FFFFFF;
    font-size: 36px;
    font-weight: bold;
    text-shadow: 3px 3px 8px rgba(0, 0, 0, 0.8), 0 0 15px rgba(255, 255, 255, 0.5);
    background: linear-gradient(145deg, rgba(0, 0, 0, 0.6), rgba(0, 0, 0, 0.4));
    padding: 10px 20px;
    border-radius: 15px;
    border: 2px solid rgba(255, 215, 0, 0.3);
    animation: titlePulse 3s ease infinite;
    z-index: 2;
    display: flex;
    align-items: center;
    justify-content: center;
    /* background-image: url('assets/images/metal_texture.jpg'); */ /* Removed due to missing file */
    background-size: cover;
    background-position: center;
    color: #FFD700;
    text-shadow: 3px 3px 8px rgba(0, 0, 0, 0.8), 0 0 15px rgba(255, 215, 0, 0.5);
}

@keyframes titlePulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.05); }
    100% { transform: scale(1); }
}

/* 添加背景遮罩以增强对比度 */
body::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.3);
    z-index: 0;
}

/* 添加游戏控制说明 */
#game-controls {
    position: absolute;
    bottom: 20px;
    left: 20px;
    color: #FFFFFF;
    font-size: 18px;
    font-weight: bold;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.8), 0 0 10px rgba(255, 255, 255, 0.5);
    background: linear-gradient(145deg, rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0.3));
    padding: 10px 20px;
    border-radius: 10px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    z-index: 2;
    display: none; /* 初始隐藏，游戏开始后显示 */
}

#game-controls p {
    margin: 5px 0;
}

/* 添加游戏状态显示 */
#game-status {
    position: absolute;
    bottom: 20px;
    right: 20px;
    color: #FFD700;
    font-size: 20px;
    font-weight: bold;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.8), 0 0 10px rgba(255, 215, 0, 0.5);
    background: linear-gradient(145deg, rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0.3));
    padding: 10px 20px;
    border-radius: 10px;
    border: 2px solid rgba(255, 215, 0, 0.3);
    z-index: 2;
    display: none; /* 初始隐藏，游戏结束后显示 */
}

/* 添加游戏开始按钮 */
#start-button {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: #FFFFFF;
    font-size: 30px;
    font-weight: bold;
    text-shadow: 3px 3px 8px rgba(0, 0, 0, 0.8), 0 0 15px rgba(255, 255, 255, 0.5);
    background: linear-gradient(145deg, #FF4500, #FF6347);
    padding: 20px 40px;
    border-radius: 15px;
    border: 3px solid rgba(255, 255, 255, 0.5);
    cursor: pointer;
    z-index: 3;
    animation: startButtonPulse 2s ease infinite;
    display: none; /* 初始隐藏，游戏加载完成后显示 */
}

@keyframes startButtonPulse {
    0% { transform: translate(-50%, -50%) scale(1); }
    50% { transform: translate(-50%, -50%) scale(1.1); }
    100% { transform: translate(-50%, -50%) scale(1); }
}

/* 添加游戏结束提示框 */
#game-over {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: #FFD700;
    font-size: 40px;
    font-weight: bold;
    text-shadow: 4px 4px 10px rgba(0, 0, 0, 0.9), 0 0 20px rgba(255, 215, 0, 0.8);
    background: linear-gradient(145deg, rgba(0, 0, 0, 0.7), rgba(0, 0, 0, 0.5));
    padding: 30px 60px;
    border-radius: 20px;
    border: 3px solid rgba(255, 215, 0, 0.5);
    box-shadow: 0 0 30px rgba(255, 215, 0, 0.7);
    z-index: 3;
    display: none; /* 初始隐藏，游戏结束后显示 */
    animation: gameOverAppear 1s ease;
    text-align: center;
}

@keyframes gameOverAppear {
    0% { opacity: 0; transform: translate(-50%, -50%) scale(0.5); }
    100% { opacity: 1; transform: translate(-50%, -50%) scale(1); }
}

#game-over p {
    margin: 10px 0;
    font-size: 24px;
}

#challenge-result-detail,
#challenge-win-count {
    font-size: 24px;
    margin: 10px 0;
}

#restart-button,
#return-to-menu-button,
#open-upgrade-panel-button-gameover {
    color: #FFFFFF;
    font-size: 24px;
    font-weight: bold;
    text-shadow: 2px 2px 5px rgba(0, 0, 0, 0.8), 0 0 10px rgba(255, 255, 255, 0.5);
    background: linear-gradient(145deg, #FF4500, #FF6347);
    padding: 10px 30px;
    border-radius: 10px;
    border: 2px solid rgba(255, 255, 255, 0.5);
    cursor: pointer;
    margin-top: 20px;
    margin-left: auto;
    margin-right: auto;
    display: block;
    animation: restartButtonPulse 2s ease infinite;
}

#game-over button + button {
    margin-top: 12px;
}

@keyframes restartButtonPulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.05); }
    100% { transform: scale(1); }
}

/* --- 强化面板样式 --- */
#upgrade-panel {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 600px; /* 或者使用百分比，例如 70vw */
    max-height: 80vh;
    overflow-y: auto;
    background-color: rgba(30, 30, 50, 0.95); /* 深蓝紫色背景 */
    color: #FFF;
    border: 3px solid rgba(255, 215, 0, 0.7); /* 金色边框 */
    border-radius: 15px;
    padding: 20px;
    box-shadow: 0 0 25px rgba(255, 215, 0, 0.5);
    z-index: 100; /* 确保在最上层 */
    font-family: 'Arial', sans-serif;
    /* 🚀 增强动画效果 */
    animation: slideInFromTop 0.5s cubic-bezier(0.4, 0, 0.2, 1);
    backdrop-filter: blur(10px);
}

#upgrade-panel h2 {
    text-align: center;
    color: #FFD700; /* 金色标题 */
    margin-top: 0;
    margin-bottom: 20px;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.7);
}

#upgrade-panel h3 {
    color: #ADD8E6; /* 淡蓝色副标题 */
    border-bottom: 1px solid rgba(255, 215, 0, 0.5);
    padding-bottom: 5px;
    margin-top: 25px;
    margin-bottom: 15px;
}

#upgrade-panel p#currency-display { /* 给显示总积分的p一个特定id，方便样式 */
    text-align: center;
    font-size: 1.2em;
    margin-bottom: 20px;
    color: #FFD700;
}

#upgrade-panel .upgrade-category {
    margin-bottom: 20px;
}

#upgrade-panel .upgrade-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px 5px;
    margin-bottom: 8px;
    background-color: rgba(0, 0, 0, 0.2);
    border-radius: 5px;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

#upgrade-panel .upgrade-item span {
    margin: 0 5px;
}

#upgrade-panel .item-name {
    flex-basis: 30%; /* 调整名称宽度占比 */
    font-weight: bold;
}
#upgrade-panel .item-level {
    flex-basis: 15%;
    text-align: center;
}
#upgrade-panel .item-effect {
    flex-basis: 25%;
    font-size: 0.9em;
    color: #ccc;
}
#upgrade-panel .item-cost {
    flex-basis: 15%;
    text-align: right;
    color: #FFD700;
}


#upgrade-panel button {
    background: linear-gradient(145deg, #FF8C00, #FFD700); /* 橙色到金色渐变 */
    color: #000; /* 黑色文字 */
    border: 2px solid #FFF;
    padding: 8px 15px;
    border-radius: 8px;
    cursor: pointer;
    font-weight: bold;
    text-shadow: 1px 1px 2px rgba(255,255,255,0.3);
    transition: background 0.3s ease, transform 0.1s ease;
}

#upgrade-panel button:hover {
    background: linear-gradient(145deg, #FFA500, #FFFF00); /* 悬停时更亮 */
    transform: scale(1.05);
}

#upgrade-panel button:disabled {
    background: #555;
    color: #888;
    cursor: not-allowed;
    border-color: #777;
}


#upgrade-panel #close-upgrade-panel-button {
    position: absolute;
    top: 15px;
    right: 15px;
    padding: 5px 10px;
    background: linear-gradient(145deg, #8B0000, #FF4500); /* 红色系关闭按钮 */
    color: white;
}
#upgrade-panel #close-upgrade-panel-button:hover {
    background: linear-gradient(145deg, #A52A2A, #FF6347);
}

/* 确保强化面板内的文本可选择，如果需要 */
#upgrade-panel {
    user-select: text;
}

/* 黄金飞机相关样式 */
#golden-fighter-container {
    margin-bottom: 20px;
}

#golden-fighter-container .upgrade-item {
    display: flex;
    align-items: center;
    padding: 10px;
    border-radius: 10px;
    background: linear-gradient(145deg, rgba(0, 0, 0, 0.6), rgba(0, 0, 0, 0.4));
    border: 2px solid rgba(255, 215, 0, 0.7);
    box-shadow: 0 0 15px rgba(255, 215, 0, 0.4);
    margin-bottom: 10px;
    transition: all 0.3s ease;
}

#golden-fighter-container .upgrade-item:hover {
    box-shadow: 0 0 20px rgba(255, 215, 0, 0.7);
    transform: translateY(-2px);
}

#golden-fighter-container img {
    margin-right: 15px;
    border-radius: 5px;
    box-shadow: 0 0 10px rgba(255, 215, 0, 0.6);
}

#golden-fighter-container .item-name {
    color: gold;
    font-size: 20px;
    font-weight: bold;
    text-shadow: 0 0 5px rgba(255, 215, 0, 0.7);
    display: block;
    margin-bottom: 5px;
}

#golden-fighter-container .item-effect {
    color: #FFFFFF;
    font-size: 14px;
    margin: 5px 0;
}

#golden-fighter-status {
    margin-top: 10px;
    display: flex;
    flex-direction: column;
    gap: 5px;
}

#golden-fighter-status button {
    background: linear-gradient(145deg, #FFD700, #FFA500);
    color: #000;
    border: none;
    padding: 8px 12px;
    border-radius: 5px;
    cursor: pointer;
    font-weight: bold;
    transition: all 0.2s ease;
    margin-top: 5px;
}

#golden-fighter-status button:hover {
    transform: scale(1.05);
    box-shadow: 0 0 10px rgba(255, 215, 0, 0.8);
}

#golden-fighter-status button:disabled {
    background: linear-gradient(145deg, #555, #333);
    color: #888;
    cursor: not-allowed;
    box-shadow: none;
}

.using-golden-fighter {
    position: absolute;
    top: 10px;
    left: 10px;
    background: linear-gradient(145deg, rgba(255, 215, 0, 0.8), rgba(255, 165, 0, 0.8));
    color: #000;
    padding: 5px 10px;
    border-radius: 5px;
    font-weight: bold;
    font-size: 14px;
    z-index: 10;
    box-shadow: 0 0 10px rgba(255, 215, 0, 0.7);
    animation: pulseGolden 2s infinite;
}

@keyframes pulseGolden {
    0% { box-shadow: 0 0 10px rgba(255, 215, 0, 0.7); }
    50% { box-shadow: 0 0 20px rgba(255, 215, 0, 0.9); }
    100% { box-shadow: 0 0 10px rgba(255, 215, 0, 0.7); }
}

/* --- 作弊面板样式 --- */
#cheat-panel {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    padding: 20px;
    background: rgba(30, 30, 50, 0.95);
    color: #fff;
    border: 3px solid rgba(255, 215, 0, 0.7);
    border-radius: 15px;
    box-shadow: 0 0 25px rgba(255, 215, 0, 0.5);
    z-index: 110;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

#cheat-panel button {
    background: linear-gradient(145deg, #FF8C00, #FFD700);
    color: #000;
    border: none;
    padding: 8px 15px;
    border-radius: 8px;
    cursor: pointer;
    font-weight: bold;
    transition: background 0.3s ease;
}

#cheat-panel button:hover {
    background: linear-gradient(145deg, #FFA500, #FFFF00);
}

/* Boss关挑战按钮 */
#boss-start-button {
    position: absolute;
    top: calc(50% + 100px); /* 位于开始按钮正下方约100px */
    left: 50%;
    transform: translate(-50%, -50%);
    color: #FFFFFF;
    font-size: 26px;
    font-weight: bold;
    text-shadow: 3px 3px 8px rgba(0, 0, 0, 0.8), 0 0 15px rgba(173, 216, 230, 0.8);
    background: linear-gradient(145deg, #1E90FF, #00BFFF); /* 蓝色系渐变与普通开始按钮区分 */
    padding: 18px 38px;
    border-radius: 15px;
    border: 3px solid rgba(255, 255, 255, 0.5);
    cursor: pointer;
    z-index: 3;
    animation: bossButtonPulse 2s ease infinite;
    display: none; /* 初始隐藏，JS 控制显示 */
}

#challenge-start-button {
    position: absolute;
    top: calc(50% + 180px);
    left: 50%;
    transform: translate(-50%, -50%);
    color: #FFFFFF;
    font-size: 24px;
    font-weight: bold;
    text-shadow: 3px 3px 8px rgba(0, 0, 0, 0.8), 0 0 15px rgba(147, 112, 219, 0.8);
    background: linear-gradient(145deg, #7B68EE, #6A5ACD);
    padding: 16px 34px;
    border-radius: 15px;
    border: 3px solid rgba(255, 255, 255, 0.4);
    cursor: pointer;
    z-index: 3;
    animation: bossButtonPulse 2.2s ease infinite;
    display: none;
}

#challenge-rules {
    position: absolute;
    top: calc(50% + 240px);
    left: 50%;
    transform: translate(-50%, -50%);
    color: #FFFFFF;
    font-size: 16px;
    font-weight: bold;
    text-shadow: 2px 2px 5px rgba(0, 0, 0, 0.8);
    background: rgba(45, 45, 70, 0.85);
    padding: 10px 18px;
    border-radius: 12px;
    border: 2px solid rgba(147, 112, 219, 0.8);
    z-index: 3;
    display: none;
}

#challenge-win-display {
    position: absolute;
    top: 90px;
    left: 20px;
    color: #FFD700;
    font-size: 20px;
    font-weight: bold;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.8);
    background: linear-gradient(145deg, rgba(0, 0, 0, 0.6), rgba(0, 0, 0, 0.4));
    padding: 8px 16px;
    border-radius: 12px;
    border: 2px solid rgba(255, 215, 0, 0.4);
    box-shadow: 0 0 12px rgba(255, 215, 0, 0.4);
    display: none;
}

@keyframes bossButtonPulse {
    0% { transform: translate(-50%, -50%) scale(1); }
    50% { transform: translate(-50%, -50%) scale(1.08); }
    100% { transform: translate(-50%, -50%) scale(1); }
}

/* ============================================================================
   UI 视觉反馈增强样式 - 从 ui-enhancements.css 合并
   主要改进：按钮动画、渐变效果、响应式交互
   ============================================================================ */

/* 🎨 按钮悬停动画增强 */
button {
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    overflow: hidden;
}

button::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;
}

button:hover::before {
    left: 100%;
}

button:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.3);
}

button:active {
    transform: translateY(0px);
    transition: transform 0.1s;
}

/* 🚀 升级面板增强动画 - 与原有样式合并 */

@keyframes slideInFromTop {
    0% {
        opacity: 0;
        transform: translate(-50%, -60%);
    }
    100% {
        opacity: 1;
        transform: translate(-50%, -50%);
    }
}

/* 🎯 升级项目悬停效果增强 */
.upgrade-item {
    transition: all 0.3s ease;
}

.upgrade-item:hover {
    background-color: rgba(255, 215, 0, 0.1);
    border-color: rgba(255, 215, 0, 0.3);
    transform: translateX(5px);
    box-shadow: 0 4px 15px rgba(255, 215, 0, 0.2);
}

.upgrade-item:hover .item-name {
    color: #FFD700;
    text-shadow: 0 0 8px rgba(255, 215, 0, 0.6);
}

/* ✨ 进度条动画效果 */
.progress-bar {
    position: relative;
    overflow: hidden;
    border-radius: 10px;
    background: rgba(0, 0, 0, 0.6);
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, #FF6B35, #F7931E);
    border-radius: 10px;
    transition: width 0.8s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    overflow: hidden;
}

.progress-fill::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(
        90deg,
        transparent 0%,
        rgba(255, 255, 255, 0.4) 50%,
        transparent 100%
    );
    animation: shimmer 2s infinite;
}

@keyframes shimmer {
    0% {
        transform: translateX(-100%);
    }
    100% {
        transform: translateX(100%);
    }
}

/* 🎪 成功/错误提示动画 */
.notification {
    position: fixed;
    top: 20px;
    right: 20px;
    padding: 15px 25px;
    border-radius: 8px;
    color: white;
    font-weight: bold;
    z-index: 1000;
    animation: slideInRight 0.5s ease, fadeOut 0.5s ease 2.5s forwards;
}

.notification.success {
    background: linear-gradient(135deg, #4CAF50, #45a049);
    box-shadow: 0 4px 15px rgba(76, 175, 80, 0.3);
}

.notification.error {
    background: linear-gradient(135deg, #f44336, #da190b);
    box-shadow: 0 4px 15px rgba(244, 67, 54, 0.3);
}

.notification.info {
    background: linear-gradient(135deg, #2196F3, #1976D2);
    box-shadow: 0 4px 15px rgba(33, 150, 243, 0.3);
}

@keyframes slideInRight {
    0% {
        opacity: 0;
        transform: translateX(100%);
    }
    100% {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes fadeOut {
    0% {
        opacity: 1;
    }
    100% {
        opacity: 0;
        transform: translateX(100%);
    }
}

/* 🌟 分数增长动画增强 */
#score.score-increase {
    animation: scoreGrowth 0.6s ease;
}

@keyframes scoreGrowth {
    0% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.15);
        text-shadow: 
            3px 3px 6px rgba(0, 0, 0, 0.8), 
            0 0 25px rgba(255, 215, 0, 1),
            0 0 35px rgba(255, 255, 255, 0.8);
    }
    100% {
        transform: scale(1);
    }
}

/* ⚡ 护盾条脉冲效果 */
.shield-bar {
    position: relative;
    border-radius: 3px;
    overflow: hidden;
}

.shield-bar.low-shield {
    animation: shieldPulse 1s infinite;
}

@keyframes shieldPulse {
    0%, 100% {
        box-shadow: 0 0 5px rgba(0, 191, 255, 0.5);
    }
    50% {
        box-shadow: 0 0 15px rgba(0, 191, 255, 0.8);
    }
}

/* 🔥 Boss血条危险状态 */
.boss-health.critical {
    animation: criticalPulse 0.8s infinite;
}

@keyframes criticalPulse {
    0%, 100% {
        border-color: #ff3333;
        box-shadow: 0 0 8px rgba(255, 51, 51, 0.4);
    }
    50% {
        border-color: #ff6666;
        box-shadow: 0 0 20px rgba(255, 51, 51, 0.8);
    }
}

/* 🎨 道具发光效果 */
.power-up {
    animation: powerUpGlow 2s infinite ease-in-out;
}

@keyframes powerUpGlow {
    0%, 100% {
        filter: drop-shadow(0 0 5px currentColor);
    }
    50% {
        filter: drop-shadow(0 0 15px currentColor);
    }
}

/* 💫 暴击文字效果 */
.critical-text {
    animation: criticalBounce 0.8s ease;
    color: #ff4444;
    font-weight: bold;
}

@keyframes criticalBounce {
    0% {
        transform: scale(0.5) rotate(-5deg);
        opacity: 0;
    }
    30% {
        transform: scale(1.3) rotate(5deg);
        opacity: 1;
    }
    60% {
        transform: scale(0.9) rotate(-2deg);
    }
    100% {
        transform: scale(1) rotate(0deg);
        opacity: 1;
    }
}

/* 🌈 彩虹文字效果（用于特殊奖励）*/
.rainbow-text {
    background: linear-gradient(
        45deg,
        #ff0000, #ff8000, #ffff00, #80ff00,
        #00ff00, #00ff80, #00ffff, #0080ff,
        #0000ff, #8000ff, #ff00ff, #ff0080
    );
    background-size: 400% 400%;
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    animation: rainbowShift 3s ease infinite;
}

@keyframes rainbowShift {
    0%, 100% {
        background-position: 0% 50%;
    }
    50% {
        background-position: 100% 50%;
    }
}

/* 📱 响应式调整 */
@media (max-width: 768px) {
    #upgrade-panel {
        width: 90vw;
        max-height: 70vh;
    }
    
    button {
        padding: 12px 20px;
        font-size: 16px;
    }
    
    .upgrade-item {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .upgrade-item span {
        margin: 2px 0;
    }
}

/* 🎪 加载动画 */
.loading-spinner {
    border: 3px solid rgba(255, 215, 0, 0.3);
    border-top: 3px solid #FFD700;
    border-radius: 50%;
    width: 30px;
    height: 30px;
    animation: spin 1s linear infinite;
    display: inline-block;
    margin-left: 10px;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}