body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: transparent;
    color: #2c3e50;
    line-height: 1.6;
    margin: 0;
    padding: 0;
    overflow-x: hidden;
}
.dna-bg {
    position: fixed;
    top: 0; left: 0; width: 100vw; height: 100vh;
    z-index: -1;
    background: #f4f7fa;
    overflow: hidden;
}
.helix-wrapper {
    position: absolute;
    top: 100%;
    transform-style: preserve-3d;
    perspective: 1000px;
    animation: floatUp linear infinite;
}
.helix-inner {
    transform-style: preserve-3d;
}
.dna-3d {
    position: relative;
    transform-style: preserve-3d;
    animation: rotateDNA 30s linear infinite;
}
@keyframes rotateDNA {
    0% { transform: rotateZ(45deg) rotateX(20deg) rotateY(0deg); }
    100% { transform: rotateZ(45deg) rotateX(20deg) rotateY(360deg); }
}
@keyframes floatUp {
    0% { transform: translateY(200px) scale(var(--s)); opacity: 0; }
    10% { opacity: 0.35; }
    90% { opacity: 0.35; }
    100% { transform: translateY(-120vh) scale(var(--s)); opacity: 0; }
}
.rung {
    position: absolute;
    left: -80px;
    width: 160px;
    height: 2px;
    transform-style: preserve-3d;
    transform: rotateY(calc(var(--i) * 15deg));
}
.dot {
    position: absolute;
    top: -6px;
    width: 14px; height: 14px;
    border-radius: 50%;
}
.dot-left {
    left: 0;
    background: hsla(var(--hue), 40%, 65%, 0.4);
    box-shadow: 0 0 6px hsla(var(--hue), 40%, 60%, 0.2);
}
.dot-right {
    right: 0;
    background: hsla(calc(var(--hue) + 180), 40%, 65%, 0.4);
    box-shadow: 0 0 6px hsla(calc(var(--hue) + 180), 40%, 60%, 0.2);
}
.line {
    position: absolute;
    top: 0; left: 0; width: 100%; height: 2px;
    background: linear-gradient(90deg, hsla(var(--hue), 40%, 60%, 0.3), hsla(calc(var(--hue) + 180), 40%, 60%, 0.3));
    opacity: 0.3;
    box-shadow: 0 0 4px rgba(255,255,255,0.1);
}