.background-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    overflow: hidden;
    background-color: #f0f7ff;
}

/* 太阳元素 */
.sun {
    position: absolute;
    top: 50px;
    right: 35%;
    width: 60px;
    height: 60px;
    background: radial-gradient(circle, #ffeb3b 30%, #ff9800 70%);
    border-radius: 50%;
    box-shadow: 0 0 40px rgba(255, 152, 0, 0.6);
    z-index: 0;
    animation: sun-pulse 8s ease-in-out infinite;
}

/* 蓝色云元素 */
.cloud {
    position: absolute;
    background: rgba(135, 206, 250, 0.8);
    border-radius: 50px;
    box-shadow: 0 8px 15px rgba(0, 0, 0, 0.1);
    z-index: -1;
}

.cloud-1 {
    top: 120px;
    left: -150px;
    width: 120px;
    height: 40px;
    animation: cloud-float 15s linear infinite;
}

.cloud-2 {
    top: 180px;
    right: -150px;
    width: 160px;
    height: 50px;
    animation: cloud-float 20s linear infinite reverse;
}

.cloud-3 {
    top: 60px;
    left: -100px;
    width: 100px;
    height: 35px;
    animation: cloud-float 12s linear infinite;
}

/* 云朵的伪元素，创建更自然的形状 */
.cloud::before,
.cloud::after {
    content: '';
    position: absolute;
    background: rgba(135, 206, 250, 0.8);
    border-radius: 50%;
}

.cloud::before {
    width: 50px;
    height: 50px;
    top: -20px;
    left: 15px;
}

.cloud::after {
    width: 60px;
    height: 60px;
    top: -30px;
    right: 15px;
}

@keyframes sun-pulse {
    0%, 100% {
        transform: scale(1);
        box-shadow: 0 0 40px rgba(255, 152, 0, 0.6);
    }
    50% {
        transform: scale(1.1);
        box-shadow: 0 0 60px rgba(255, 152, 0, 0.8);
    }
}

@keyframes cloud-float {
    0% {
        transform: translateX(-150px);
    }
    100% {
        transform: translateX(calc(100vw + 150px));
    }
}

.modern-gradient {
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: linear-gradient(
        135deg,
        rgba(24, 144, 255, 0.6) 0%,
        rgba(64, 169, 255, 0.5) 20%,
        rgba(135, 208, 255, 0.4) 40%,
        rgba(255, 175, 64, 0.4) 60%,
        rgba(255, 122, 69, 0.5) 80%,
        rgba(245, 85, 65, 0.6) 100%
    );
    animation: gradient-flow 25s ease-in-out infinite;
    border-radius: 40% 60% 60% 40% / 40% 40% 60% 60%;
    filter: blur(30px);
}

.modern-gradient::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: radial-gradient(
        circle at 25% 65%,
        rgba(24, 144, 255, 0.6) 0%,
        transparent 60%
    ), radial-gradient(
        circle at 75% 35%,
        rgba(245, 85, 65, 0.5) 0%,
        transparent 60%
    );
    animation: pulse-effect 18s ease-in-out infinite alternate;
    border-radius: 40% 60% 60% 40% / 40% 40% 60% 60%;
    filter: blur(20px);
}

@keyframes gradient-flow {
    0%, 100% {
        transform: rotate(0deg) scale(1);
        opacity: 0.8;
    }
    25% {
        transform: rotate(90deg) scale(1.1);
        opacity: 0.6;
    }
    50% {
        transform: rotate(180deg) scale(0.9);
        opacity: 0.9;
    }
    75% {
        transform: rotate(270deg) scale(1.05);
        opacity: 0.7;
    }
}

@keyframes pulse-effect {
    0% {
        transform: scale(1) rotate(0deg);
        opacity: 0.5;
    }
    50% {
        transform: scale(1.2) rotate(180deg);
        opacity: 0.8;
    }
    100% {
        transform: scale(1) rotate(360deg);
        opacity: 0.6;
    }
}

/* 手机端背景优化 */
@media (max-width: 768px) {
    .modern-gradient {
        animation-duration: 25s;
    }
    
    .modern-gradient::before {
        animation-duration: 18s;
    }
}

/* 减少动画以节省电池 */
@media (prefers-reduced-motion: reduce) {
    .modern-gradient,
    .modern-gradient::before {
        animation: none;
    }
    
    .modern-gradient {
        background: linear-gradient(
            135deg,
            rgba(64, 169, 255, 0.3) 0%,
            rgba(255, 175, 64, 0.2) 50%,
            rgba(255, 122, 69, 0.25) 100%
        );
    }
}