/* ===== SCROLL CONFIGURATION ===== */
html {
    scroll-behavior: smooth;
}

main {
    position: relative;
    width: 100%;
    height: 200vh;
    z-index: 5; /* ensure main/site content sits above video and small overlays */
}

/* Logo central de la section intro */
#circle-logo {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    z-index: 4;
    width: 460px !important;
    height: auto !important;
    will-change: transform, filter, opacity;
    pointer-events: none;
    user-select: none;
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    transform-origin: center center;
    backface-visibility: hidden;
    -webkit-backface-visibility: hidden;
}

#circle-logo * {
    pointer-events: none;
    user-select: none;
}

/* Vidéo de fond de la section intro */
#circle-video {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    object-fit: cover;
    z-index: 0; /* video sits at the bottom */
}

#video-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: radial-gradient(circle, var(--video-overlay-start) 0%, var(--video-overlay-end) 20%);
    mix-blend-mode: soft-light;
    z-index: 1; 
    opacity: 0.8;
    backdrop-filter: grayscale(1) brightness(0.5) saturate(0.5);
    pointer-events: none;
    will-change: opacity;
}

#vignette-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: radial-gradient(circle, var(--vignette-overlay-start) 0%, var(--vignette-overlay-end) 100%);
    -webkit-mask-image: radial-gradient(circle, transparent 160px, white 161px);
    -webkit-mask-size: auto;
    -webkit-mask-repeat: no-repeat;
    -webkit-mask-position: center;
    mask-image: radial-gradient(circle, transparent 160px, white 161px);
    mask-size: auto;
    mask-repeat: no-repeat;
    mask-position: center;
    pointer-events: none;
    z-index: 2; /* vignette above video but below main content */
    will-change: -webkit-mask-image, mask-image, opacity;
}

#vignette-overlay::after {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: 
        linear-gradient(white 1px, transparent 1px),
        linear-gradient(90deg, white 1px, transparent 1px);
    background-size: 80px 80px;
    opacity: 0.05;
    -webkit-mask-image: inherit;
    -webkit-mask-size: inherit;
    -webkit-mask-repeat: inherit;
    -webkit-mask-position: inherit;
    mask-image: inherit;
    mask-size: inherit;
    mask-repeat: inherit;
    mask-position: inherit;
    animation: moveGrid 2s linear infinite;
    will-change: background-position;
}


@keyframes moveGrid {
    from { background-position: 0 0; }
    to   { background-position: 80px 80px; }
}