r · CSS
/*
  protostar.css - styles for the animated protostar background (home page only).
  Load after main_style.css.
*/
 
/* Lets body#home's background (the HL Tau image) sit underneath the canvas
   so it can act as the fallback. Remove if you ever style html's background. */
html { background: none; }
 
#protostar-bg {
    position: fixed;
    inset: 0;
    width: 100%;
    height: 100%;
    display: block;
    z-index: -1;
    transition: opacity 3s ease;
}
#protostar-bg.faded { opacity: 0; }
 
/* During the intro, the animation has the stage; caption and scroll hint fade in after. */
#HL-Tau-Caption,
.scroll-hint { transition: opacity 1.5s ease, visibility 1.5s; }
body.protostar-intro #HL-Tau-Caption,
body.protostar-intro .scroll-hint { opacity: 0; }
 
/* Caption: show the one that matches what's on screen */
#HL-Tau-Caption .caption-sim { display: none; }
body[data-hero="sim"] #HL-Tau-Caption .caption-sim { display: block; }
body[data-hero="sim"] #HL-Tau-Caption .caption-image { display: none; }
 
/* Skip / Replay button: sits on the first screen and scrolls away with it */
#protostar-ctrl {
    position: absolute;
    left: 30px;
    top: calc(100dvh - 70px);
    z-index: 5;
    padding: 7px 16px;
    font: 13px Georgia, 'Times New Roman', serif;
    letter-spacing: 0.04em;
    color: rgba(255, 255, 255, 0.85);
    background: rgba(0, 0, 0, 0.35);
    border: 1px solid rgba(255, 255, 255, 0.25);
    border-radius: 999px;
    cursor: pointer;
    backdrop-filter: blur(4px);
}
#protostar-ctrl:hover { color: #3399ff; border-color: #3399ff; }
 
/* Name + quick links on the first screen */
.intro-title {
    position: absolute;
    top: 0;
    left: 6vw;
    right: 6vw;
    height: 100dvh;
    box-sizing: border-box;
    padding-bottom: 16vh;
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
    z-index: 2;
    pointer-events: none;
    color: #ffffff;
}
.intro-title h1 {
    margin: 0 0 0.3em;
    font-weight: normal;
    font-size: clamp(2.2rem, 5.5vw, 4.6rem);
    letter-spacing: 0.02em;
    text-shadow: 0 0 30px rgba(0, 0, 0, 0.8);
}
.intro-title p {
    margin: 0 0 1.5em;
    font-size: clamp(0.8rem, 1.2vw, 1rem);
    letter-spacing: 0.12em;
    text-transform: uppercase;
    opacity: 0.8;
    text-shadow: 0 0 20px rgba(0, 0, 0, 0.9);
}
.intro-title .intro-links { display: flex; flex-wrap: wrap; gap: 0.6em 2em; pointer-events: auto; }
.intro-title .intro-links a {
    color: #ffffff;
    text-decoration: none;
    font-size: clamp(0.95rem, 1.3vw, 1.15rem);
    letter-spacing: 0.05em;
    padding-bottom: 3px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.35);
}
.intro-title .intro-links a:hover { color: #3399ff; border-color: #3399ff; }
 
/* Staggered fade-in: name, then subtitle, then links */
.intro-title h1,
.intro-title p,
.intro-title .intro-links { transition: opacity 1.8s ease, transform 1.8s ease; }
.intro-title p   { transition-delay: 0.5s; }
.intro-title .intro-links { transition-delay: 1s; }
body.protostar-intro .intro-title h1,
body.protostar-intro .intro-title p,
body.protostar-intro .intro-title .intro-links {
    opacity: 0;
    transform: translateY(14px);
    transition-delay: 0s;
    transition-duration: 0s;
}
body.protostar-intro .intro-title .intro-links { pointer-events: none; }
 
/* Phones: leave room for the caption at the bottom */
@media (max-width: 700px) {
    .intro-title { padding-bottom: 30vh; }
}