/* ============================================================
   stars.css — drifting starfield + colour wash backdrop
   Pure CSS. Three parallax layers of box-shadow stars.
   ============================================================ */

.sky {
  position: absolute;
  inset: 0;
  overflow: hidden;
  pointer-events: none;
  z-index: 0;
}

/* ── Star layers ────────────────────────────────────────── */
.sky__layer {
  position: absolute;
  top: 0;
  left: 0;
  border-radius: 50%;
  background: transparent;
}

/* Far layer — tiny, slow, dense */
.sky__layer--far {
  width: 1px;
  height: 1px;
  opacity: 0.5;
  animation: skyDrift 190s linear infinite;
  box-shadow:
    /* white */
    12vw 8vh var(--star), 27vw 22vh var(--star), 41vw 5vh var(--star),
    58vw 31vh var(--star), 73vw 14vh var(--star), 88vw 27vh var(--star),
    34vw 47vh var(--star), 19vw 61vh var(--star), 63vw 55vh var(--star),
    92vw 68vh var(--star), 7vw 79vh var(--star), 48vw 88vh var(--star),
    76vw 92vh var(--star), 22vw 36vh var(--star), 55vw 73vh var(--star),
    /* blue */
    15vw 18vh var(--star-blue), 69vw 41vh var(--star-blue),
    39vw 66vh var(--star-blue), 84vw 12vh var(--star-blue),
    8vw 52vh var(--star-blue), 96vw 45vh var(--star-blue),
    /* cyan */
    31vw 12vh var(--star-cyan), 60vw 25vh var(--star-cyan),
    45vw 82vh var(--star-cyan), 81vw 74vh var(--star-cyan),
    3vw 33vh var(--star-cyan), 25vw 95vh var(--star-cyan);
}

/* Mid layer — medium, moderate speed */
.sky__layer--mid {
  width: 1.5px;
  height: 1.5px;
  opacity: 0.62;
  animation: skyDrift 130s linear infinite;
  box-shadow:
    9vw 13vh var(--star), 36vw 9vh var(--star-blue), 52vw 38vh var(--star),
    78vw 21vh var(--star), 21vw 44vh var(--star-cyan), 65vw 62vh var(--star),
    4vw 71vh var(--star), 88vw 57vh var(--star-blue), 43vw 84vh var(--star),
    30vw 27vh var(--star), 71vw 88vh var(--star-cyan), 95vw 33vh var(--star),
    17vw 55vh var(--star-blue), 57vw 16vh var(--star), 8vw 91vh var(--star-cyan),
    48vw 49vh var(--star);
}

/* Near layer — brightest, fastest, sparse */
.sky__layer--near {
  width: 2px;
  height: 2px;
  opacity: 0.82;
  animation: skyDrift 85s linear infinite;
  box-shadow:
    24vw 17vh var(--star), 61vw 33vh var(--star-blue), 82vw 71vh var(--star),
    13vw 48vh var(--star-cyan), 44vw 62vh var(--star), 91vw 24vh var(--star),
    33vw 91vh var(--star-blue), 68vw 8vh var(--star), 6vw 39vh var(--star-cyan),
    53vw 79vh var(--star);
}

/* Bright stars get an occasional twinkle */
.sky__layer--near::after {
  content: "";
  position: absolute;
  width: 2.5px;
  height: 2.5px;
  border-radius: 50%;
  box-shadow:
    24vw 17vh rgba(255, 255, 255, 0.95),
    61vw 33vh rgba(160, 200, 255, 0.95),
    82vw 71vh rgba(255, 255, 255, 0.9),
    13vw 48vh rgba(150, 194, 255, 0.95);
  animation: skyTwinkle 5.5s var(--ease) infinite;
}

@keyframes skyDrift {
  from { transform: translate3d(0, 0, 0); }
  to   { transform: translate3d(-6vw, -5vh, 0); }
}

@keyframes skyTwinkle {
  0%, 100% { opacity: 0.25; }
  50%      { opacity: 1; }
}

/* ── Colour washes ──────────────────────────────────────── */
.sky__aurora {
  position: absolute;
  inset: -10%;
  background:
    radial-gradient(ellipse 46% 38% at 20% 14%, var(--accent-dim), transparent 62%),
    radial-gradient(ellipse 42% 34% at 80% 24%, rgba(58, 111, 216, 0.13), transparent 64%),
    radial-gradient(ellipse 50% 40% at 50% 88%, rgba(77, 141, 255, 0.1), transparent 66%),
    radial-gradient(ellipse 32% 26% at 72% 74%, rgba(109, 160, 255, 0.09), transparent 68%);
  animation: auroraShift 26s ease-in-out infinite alternate;
}

@keyframes auroraShift {
  0%   { transform: translate3d(0, 0, 0) scale(1); }
  100% { transform: translate3d(0, -2.5%, 0) scale(1.06); }
}

/* ── Shooting star ──────────────────────────────────────── */
.sky__shoot {
  position: absolute;
  top: 18%;
  left: 12%;
  width: 2px;
  height: 2px;
  border-radius: 50%;
  background: #fff;
  box-shadow: 0 0 6px 1px rgba(160, 210, 255, 0.7);
  opacity: 0;
  animation: shoot 14s linear infinite;
}

.sky__shoot::before {
  content: "";
  position: absolute;
  top: 50%;
  right: 0;
  width: 130px;
  height: 1px;
  transform: translateY(-50%);
  background: linear-gradient(to left, rgba(255, 255, 255, 0.75), transparent);
}

@keyframes shoot {
  0%      { transform: translate3d(0, 0, 0); opacity: 0; }
  3%      { opacity: 1; }
  16%     { transform: translate3d(52vw, 34vh, 0); opacity: 0; }
  100%    { transform: translate3d(52vw, 34vh, 0); opacity: 0; }
}

/* ── Reduced motion ─────────────────────────────────────── */
@media (prefers-reduced-motion: reduce) {
  .sky__layer,
  .sky__layer--near::after,
  .sky__aurora,
  .sky__shoot {
    animation: none;
  }
  .sky__shoot { opacity: 0; }
}

/* ── Performance: trim layers on small screens ──────────── */
@media (max-width: 560px) {
  .sky__layer--far { opacity: 0.38; }
  .sky__layer--mid { opacity: 0.45; }
  .sky__shoot { display: none; }
}

/* ── Devices that dislike heavy paint ───────────────────── */
@media (prefers-reduced-transparency: reduce) {
  .sky__aurora { opacity: 0.5; }
}