.lab-background {
    width: 100%;
    min-height: 250px;
    max-height: 600px;
    background: linear-gradient(135deg, #ffb347 0%, #ff7e5f 50%, #ff6a00 100%);
    position: relative;
    overflow: hidden;
    box-shadow: 0 10px 30px rgba(0,0,0,0.3);
}

/* CO2 分子動畫 */
.molecules {
    position: absolute;
    width: 100%;
    height: 100%;
}

.molecule {
    position: absolute;
    width: 8px;
    height: 8px;
    background: #ffb347;
    border-radius: 50%;
    animation: float 4s ease-in-out infinite;
    box-shadow: 0 0 8px #ff7e5f, 0 0 16px #ffb347;
}

.molecule:nth-child(1) { left: 50px; top: 100px; animation-delay: 0s; }
.molecule:nth-child(2) { top: 150px; right: 150px; animation-delay: 1s; }
.molecule:nth-child(3) { right: 250px; bottom: 80px; animation-delay: 2s; }
.molecule:nth-child(4) { bottom: 350px; left: 200px; animation-delay: 0.5s; }
.molecule:nth-child(5) { left: 450px; top: 120px; animation-delay: 1.5s; }
.molecule:nth-child(6) { top: 300px; right: 100px; animation-delay: 2.5s; }
.molecule:nth-child(7) { right: 300px; bottom: 200px; animation-delay: 3s; }
.molecule:nth-child(8) { bottom: 400px; left: 50px; animation-delay: 1s; }

@keyframes float {
    0%, 100% { transform: translateY(0px) rotate(0deg); opacity: 0.7; }
    50% { transform: translateY(-20px) rotate(180deg); opacity: 1; }
}

/* 科技感光效 */
.tech-glow {
    position: absolute;
    width: 100px;
    height: 100px;
    background: radial-gradient(circle, rgba(255, 183, 77, 0.4), transparent);
    border-radius: 50%;
    animation: pulse 3s ease-in-out infinite;
}

.tech-glow:nth-child(1) { left: 100px; top: 100px; animation-delay: 0s; }
.tech-glow:nth-child(2) { right: 200px; top: 200px; animation-delay: 1s; }
.tech-glow:nth-child(3) { left: 400px; bottom: 100px; animation-delay: 2s; }

@keyframes pulse {
    0%, 100% { transform: scale(1); opacity: 0.5; }
    50% { transform: scale(1.2); opacity: 0.8; }
}

/* 標題覆蓋 */
.overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(45deg, rgba(255,140,0,0.25), rgba(255,94,98,0.10));
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    text-align: center;
    backdrop-filter: blur(3px);
}

.lab-title {
    z-index: 10;
}

.lab-title h1 {
    font-size: 3rem;
    font-weight: bold;
    padding: 1rem;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.5);
}

.lab-title p {
    font-size: 1.3rem;
    margin-bottom: 0;
    padding: 1rem;
    text-shadow: 1px 1px 2px rgba(0,0,0,0.5);
}

.download-info {
    margin-top: 30px;
    padding: 20px;
    background: rgba(255,255,255,0.1);
    border-radius: 10px;
    text-align: center;
    color: white;
}