body {
    margin: 0;
    padding: 0;
    font-family: 'Arial', sans-serif;
    /* 创建更清晰的透明彩虹背景 */
    background: linear-gradient(135deg, 
        rgba(255, 0, 0, 0.3) 0%, 
        rgba(255, 165, 0, 0.3) 14.28%, 
        rgba(255, 255, 0, 0.3) 28.56%, 
        rgba(0, 255, 0, 0.3) 42.84%, 
        rgba(0, 0, 255, 0.3) 57.12%, 
        rgba(75, 0, 130, 0.3) 71.4%, 
        rgba(148, 0, 211, 0.3) 85.68%, 
        rgba(255, 0, 0, 0.3) 100%);
    background-size: 400% 400%;
    animation: rainbowBackground 10s ease infinite;
    min-height: 100vh;
    overflow: hidden;
}

/* 更明显的彩虹背景动画 */
@keyframes rainbowBackground {
    0% {
        background-position: 0% 50%;
    }
    50% {
        background-position: 100% 50%;
    }
    100% {
        background-position: 0% 50%;
    }
}

.container {
    text-align: center;
    padding: 20px;
}

h1 {
    color: #FF6B6B;
    font-size: 2.5em;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
    margin-bottom: 30px;
}

.balloons-container {
    position: relative;
    width: 100%;
    height: 80vh;
}

.balloon {
    position: absolute;
    width: 100px;
    height: 120px;
    border-radius: 50%;
    cursor: pointer;
    animation: float 10s infinite ease-in-out; /* 从8s延长到10s */
    transition: transform 0.3s ease;
    bottom: -150px;
}

.balloon:before {
    content: "";
    position: absolute;
    bottom: -15px;
    left: 50%;
    transform: translateX(-50%);
    width: 2px;
    height: 50px;
    background-color: rgba(255, 255, 255, 0.7);
}

.balloon:hover {
    transform: scale(1.1);
}

.balloon-text {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: white;
    font-weight: bold;
    font-size: 30px;
    text-shadow: 1px 1px 2px rgba(0,0,0,0.5);
}

/* 不同颜色的气球 */
.balloon:nth-child(1) { background-color: #FF6B6B; left: 10%; animation-delay: 0s; }
.balloon:nth-child(2) { background-color: #4ECDC4; left: 20%; animation-delay: 2s; }
.balloon:nth-child(3) { background-color: #FFE66D; left: 30%; animation-delay: 4s; }
.balloon:nth-child(4) { background-color: #6B5B95; left: 40%; animation-delay: 6s; }
.balloon:nth-child(5) { background-color: #88D8B0; left: 50%; animation-delay: 8s; }
.balloon:nth-child(6) { background-color: #FF9AA2; left: 60%; animation-delay: 10s; }
.balloon:nth-child(7) { background-color: #FFB7B2; left: 70%; animation-delay: 12s; }
.balloon:nth-child(8) { background-color: #FFDAC1; left: 80%; animation-delay: 14s; }
.balloon:nth-child(9) { background-color: #E2F0CB; left: 90%; animation-delay: 16s; }

@keyframes float {
    0% {
        transform: translateY(0) translateX(0);
        bottom: -150px;
    }
    100% {
        transform: translateY(-100vh) translateX(30px);
        bottom: 100vh;
    }
}

/* 消息弹窗样式 */
.message-popup {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.7);
    z-index: 1000;
    justify-content: center;
    align-items: center;
}

.message-content {
    background-color: white;
    padding: 40px;
    border-radius: 20px;
    text-align: center;
    box-shadow: 0 0 30px rgba(255, 107, 107, 0.8);
    animation: popIn 0.5s ease-out;
    background: linear-gradient(135deg, #FFB6C1, #FF69B4);
}

.message-content h2 {
    color: white;
    font-size: 2.5em;
    margin-bottom: 20px;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
}

@keyframes popIn {
    0% {
        transform: scale(0.5);
        opacity: 0;
    }
    100% {
        transform: scale(1);
        opacity: 1;
    }
}

#showPhotoBtn {
    background-color: #4ECDC4;
    color: white;
    border: none;
    padding: 12px 24px;
    font-size: 1.2em;
    border-radius: 50px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 8px rgba(0,0,0,0.2);
}

#showPhotoBtn:hover {
    background-color: #3AAFA9;
    transform: scale(1.05);
}

/* 照片容器样式 */
.photo-container {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.9);
    z-index: 1001;
    justify-content: center;
    align-items: center;
}

.photo-content {
    text-align: center;
    max-width: 90%;
    max-height: 90%;
}

#birthdayPhoto {
    max-width: 80vw;
    max-height: 70vh;
    border-radius: 10px;
    box-shadow: 0 0 30px rgba(255, 255, 255, 0.5);
}

#closePhotoBtn {
    background-color: #FF6B6B;
    color: white;
    border: none;
    padding: 10px 20px;
    font-size: 1em;
    border-radius: 50px;
    cursor: pointer;
    margin-top: 20px;
    transition: all 0.3s ease;
    box-shadow: 0 4px 8px rgba(0,0,0,0.2);
}

#closePhotoBtn:hover {
    background-color: #FF5252;
    transform: scale(1.05);
}