*,
*::before,
*::after {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
}

body {
  display: flex;
  justify-content: center;
  align-items: center;
  background: radial-gradient(circle at 10% 20%, #020617, #000);
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "SF Pro Text",
    "Segoe UI", sans-serif;
  color: #e5e7eb;
  overflow: hidden;
}

.space {
  position: relative;
  width: 100vw;
  height: min(100vmin, 1280px);
  border-radius: 24px;
  background: radial-gradient(circle at 20% 0%, #1f2937, #020617 70%);
  box-shadow:
    0 22px 60px rgba(15, 23, 42, 0.9),
    0 0 0 1px rgba(148, 163, 184, 0.08);
  overflow: hidden;
}

/* Starfield layers */
.stars {
  position: absolute;
  inset: -50%;
  background-image:
    radial-gradient(2px 2px at 20% 20%, rgba(248, 250, 252, 0.7), transparent),
    radial-gradient(1.5px 1.5px at 80% 30%, rgba(191, 219, 254, 0.8), transparent),
    radial-gradient(1.4px 1.4px at 40% 70%, rgba(219, 234, 254, 0.7), transparent),
    radial-gradient(1.6px 1.6px at 70% 80%, rgba(248, 250, 252, 0.5), transparent);
  opacity: 0.5;
  animation: drift 60s linear infinite;
}

.stars--layer2 {
  filter: blur(1px);
  opacity: 0.35;
  animation-duration: 90s;
}

.stars--layer3 {
  filter: blur(2px);
  opacity: 0.2;
  animation-duration: 130s;
}

@keyframes drift {
  from { transform: translate3d(0, 0, 0); }
  to   { transform: translate3d(-6%, -4%, 0); }
}

/* Sun + glow */
.sun-glow {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 200px;
  height: 200px;
  transform: translate(-50%, -50%);
  background:
    radial-gradient(circle, rgba(251, 191, 36, 0.9), transparent 55%),
    radial-gradient(circle, rgba(248, 250, 252, 0.6), transparent 60%);
  filter: blur(40px);
  opacity: 0.9;
  mix-blend-mode: screen;
  pointer-events: none;
}

.sun {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 96px;
  height: 96px;
  transform: translate(-50%, -50%);
  border-radius: 50%;
  background:
    radial-gradient(circle at 30% 20%, #fef3c7, #facc15 40%, #f97316 70%, #b45309 100%);
  box-shadow:
    0 0 50px rgba(253, 224, 71, 0.85),
    0 0 120px rgba(251, 191, 36, 0.7);
}

.orbits {
  position: absolute;
  inset: 0;
}

/* Orbit path - elliptical with accurate eccentricities */
.orbit {
  position: absolute;
  top: 50%;
  left: 50%;
  width: calc(var(--orbit-semi-major, 210px) * 2);
  height: calc(var(--orbit-semi-minor, 210px) * 2);
  transform: translate(calc(-50% + var(--orbit-offset-x, 0px)), -50%);
  border-radius: 50%;
  border: 1px dashed rgba(148, 163, 184, 0.35);
  box-shadow:
    0 0 32px rgba(15, 23, 42, 0.9),
    inset 0 0 18px rgba(15, 23, 42, 0.8);
}

.orbit__body {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 100%;
  height: 100%;
  transform: translate(-50%, -50%);
  transform-origin: 50% 50%;
  animation: orbit-spin var(--orbit-duration, 18s) linear infinite;
}

@keyframes orbit-spin {
  from { transform: translate(-50%, -50%) rotate(0deg); }
  to   { transform: translate(-50%, -50%) rotate(360deg); }
}

.planet {
  position: absolute;
  top: 50%;
  left: 100%;
  width: var(--planet-size, 40px);
  height: var(--planet-size, 40px);
  transform: translate(-50%, -50%);
  border-radius: 50%;
  background: radial-gradient(circle at 40% 30%, #fff, #94a3b8 70%, #1f2937 100%);
  box-shadow:
    0 0 24px rgba(148, 163, 184, 0.6),
    0 0 42px rgba(148, 163, 184, 0.35);
}

.orbit--mercury {
  --orbit-semi-major: 80px;
  --orbit-semi-minor: 78.3px;  /* e=0.2056 */
  --orbit-offset-x: 16.4px;     /* focal offset */
  --orbit-duration: 6s;
}

.planet--mercury {
  --planet-size: 16px;
  background:
    radial-gradient(circle at 35% 30%, #f8fafc, #e2e8f0 45%, #64748b 70%, #1e293b 100%);
  box-shadow:
    0 0 12px rgba(148, 163, 184, 0.6),
    0 0 24px rgba(148, 163, 184, 0.35);
}

.orbit--venus {
  --orbit-semi-major: 115px;
  --orbit-semi-minor: 114.9px;   /* e=0.0068 */
  --orbit-offset-x: 0.78px;     /* focal offset */
  --orbit-duration: 10s;
}

.planet--venus {
  --planet-size: 24px;
  background:
    radial-gradient(circle at 35% 30%, #fef9c3, #facc15 45%, #eab308 70%, #78350f 100%);
  box-shadow:
    0 0 18px rgba(234, 179, 8, 0.65),
    0 0 32px rgba(217, 119, 6, 0.45);
}

.orbit--earth {
  --orbit-semi-major: 155px;
  --orbit-semi-minor: 154.8px;  /* e=0.0167 */
  --orbit-offset-x: 2.6px;        /* focal offset */
  --orbit-duration: 12s;
}

.planet--earth {
  --planet-size: 28px;
  background:
    radial-gradient(circle at 30% 25%, #e0f2fe, #38bdf8 45%, #0369a1 70%, #0b1120 100%);
  box-shadow:
    0 0 24px rgba(56, 189, 248, 0.8),
    0 0 42px rgba(59, 130, 246, 0.6);
}

.orbit--mars {
  --orbit-semi-major: 200px;
  --orbit-semi-minor: 198.3px;  /* e=0.0934 */
  --orbit-offset-x: 18.7px;     /* focal offset */
  --orbit-duration: 15s;
}

.planet--mars {
  --planet-size: 22px;
  background:
    radial-gradient(circle at 30% 25%, #fcd34d, #f97316 45%, #b45309 70%, #7c2d12 100%);
  box-shadow:
    0 0 20px rgba(249, 115, 22, 0.6),
    0 0 36px rgba(234, 88, 12, 0.45);
}

.orbit--jupiter {
  --orbit-semi-major: 270px;
  --orbit-semi-minor: 269.0px;  /* e=0.0487 */
  --orbit-offset-x: 13.2px;     /* focal offset */
  --orbit-duration: 20s;
}

.planet--jupiter {
  --planet-size: 46px;
  background:
    radial-gradient(circle at 35% 30%, #ffedd5, #fcd34d 40%, #f97316 65%, #92400e 100%);
  box-shadow:
    0 0 26px rgba(253, 186, 116, 0.7),
    0 0 48px rgba(248, 113, 113, 0.4);
}

.orbit--saturn {
  --orbit-semi-major: 345px;
  --orbit-semi-minor: 343.9px;  /* e=0.0520 */
  --orbit-offset-x: 17.9px;     /* focal offset */
  --orbit-duration: 24s;
}

.planet--saturn {
  --planet-size: 40px;
  background:
    radial-gradient(circle at 35% 30%, #fefce8, #fde68a 40%, #fbbf24 65%, #d97706 100%);
  box-shadow:
    0 0 24px rgba(251, 191, 36, 0.7),
    0 0 44px rgba(217, 119, 6, 0.45);
}

.planet--saturn .planet__ring {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 120%;
  height: 45%;
  border: 2px solid rgba(250, 204, 21, 0.55);
  border-left-color: transparent;
  border-right-color: transparent;
  border-radius: 50%;
  transform: translate(-50%, -50%) rotate(-18deg);
  box-shadow: 0 0 18px rgba(251, 191, 36, 0.35);
  mix-blend-mode: screen;
}

.orbit--uranus {
  --orbit-semi-major: 420px;
  --orbit-semi-minor: 419.3px;  /* e=0.0472 */
  --orbit-offset-x: 19.8px;     /* focal offset */
  --orbit-duration: 30s;
}

.planet--uranus {
  --planet-size: 32px;
  background:
    radial-gradient(circle at 35% 30%, #e0f2f1, #5eead4 45%, #14b8a6 70%, #115e59 100%);
  box-shadow:
    0 0 24px rgba(20, 184, 166, 0.65),
    0 0 40px rgba(45, 212, 191, 0.45);
}

.orbit--neptune {
  --orbit-semi-major: 490px;
  --orbit-semi-minor: 489.8px;  /* e=0.0086 */
  --orbit-offset-x: 4.2px;      /* focal offset */
  --orbit-duration: 36s;
}

.planet--neptune {
  --planet-size: 30px;
  background:
    radial-gradient(circle at 35% 30%, #dbeafe, #60a5fa 45%, #2563eb 70%, #1e3a8a 100%);
  box-shadow:
    0 0 26px rgba(96, 165, 250, 0.7),
    0 0 46px rgba(59, 130, 246, 0.5);
}

/* Info panel */
.info {
  position: absolute;
  bottom: 24px;
  left: 24px;
  transform: none;
  width: min(55vw, 520px);
  display: flex;
  flex-direction: column;
  align-items: stretch;
  gap: 14px;
  text-align: left;
  font-size: 14px;
  letter-spacing: 0.015em;
  color: #e2e8f0;
}

.info__line {
  margin: 0;
  color: inherit;
  opacity: 0.95;
}

.info__line:first-child {
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: rgba(148, 163, 184, 0.85);
}

.info__line strong {
  color: #bfdbfe;
  font-weight: 600;
}

.info__grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, max-content));
  column-gap: 32px;
  row-gap: 12px;
  align-items: center;
  justify-content: start;
  width: 100%;
  padding: 18px 24px;
  text-transform: uppercase;
  font-size: 11px;
  letter-spacing: 0.1em;
}

.info__grid span {
  color: rgba(148, 163, 184, 0.9);
  font-weight: 600;
}

.info__grid strong {
  color: #f8fafc;
  font-weight: 600;
  letter-spacing: 0.04em;
  padding: 4px 12px;
  border-radius: 999px;
  /* background: linear-gradient(135deg, rgba(59, 130, 246, 0.35), rgba(96, 165, 250, 0.22)); */
  box-shadow: 0 8px 18px -10px rgba(37, 99, 235, 0.8);
}

.info__note {
  color: rgba(148, 163, 184, 0.8);
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

/* Responsive scaling for smaller screens */
@media (max-width: 1200px) {
  .orbit--mercury { --orbit-semi-major: 65px; --orbit-semi-minor: 63.6px; --orbit-offset-x: 13.4px; }
  .orbit--venus { --orbit-semi-major: 95px; --orbit-semi-minor: 94.9px; --orbit-offset-x: 0.65px; }
  .orbit--earth { --orbit-semi-major: 128px; --orbit-semi-minor: 127.8px; --orbit-offset-x: 2.1px; }
  .orbit--mars { --orbit-semi-major: 165px; --orbit-semi-minor: 163.5px; --orbit-offset-x: 15.4px; }
  .orbit--jupiter { --orbit-semi-major: 220px; --orbit-semi-minor: 219.1px; --orbit-offset-x: 10.7px; }
  .orbit--saturn { --orbit-semi-major: 280px; --orbit-semi-minor: 278.9px; --orbit-offset-x: 14.6px; }
  .orbit--uranus { --orbit-semi-major: 340px; --orbit-semi-minor: 339.4px; --orbit-offset-x: 16.0px; }
  .orbit--neptune { --orbit-semi-major: 395px; --orbit-semi-minor: 394.8px; --orbit-offset-x: 3.4px; }
}

@media (max-width: 900px) {
  .sun { width: 70px; height: 70px; }
  .sun-glow { width: 150px; height: 150px; }
  
  .orbit--mercury { --orbit-semi-major: 50px; --orbit-semi-minor: 48.9px; --orbit-offset-x: 10.3px; }
  .orbit--venus { --orbit-semi-major: 72px; --orbit-semi-minor: 71.9px; --orbit-offset-x: 0.49px; }
  .orbit--earth { --orbit-semi-major: 98px; --orbit-semi-minor: 97.8px; --orbit-offset-x: 1.6px; }
  .orbit--mars { --orbit-semi-major: 128px; --orbit-semi-minor: 126.9px; --orbit-offset-x: 12.0px; }
  .orbit--jupiter { --orbit-semi-major: 170px; --orbit-semi-minor: 169.3px; --orbit-offset-x: 8.3px; }
  .orbit--saturn { --orbit-semi-major: 215px; --orbit-semi-minor: 214.2px; --orbit-offset-x: 11.2px; }
  .orbit--uranus { --orbit-semi-major: 260px; --orbit-semi-minor: 259.5px; --orbit-offset-x: 12.3px; }
  .orbit--neptune { --orbit-semi-major: 300px; --orbit-semi-minor: 299.8px; --orbit-offset-x: 2.6px; }
  
  .planet--mercury { --planet-size: 12px; }
  .planet--venus { --planet-size: 18px; }
  .planet--earth { --planet-size: 20px; }
  .planet--mars { --planet-size: 16px; }
  .planet--jupiter { --planet-size: 34px; }
  .planet--saturn { --planet-size: 30px; }
  .planet--uranus { --planet-size: 24px; }
  .planet--neptune { --planet-size: 22px; }
}

@media (max-width: 700px) {
  .sun { width: 50px; height: 50px; }
  .sun-glow { width: 110px; height: 110px; }
  
  .orbit--mercury { --orbit-semi-major: 38px; --orbit-semi-minor: 37.2px; --orbit-offset-x: 7.8px; }
  .orbit--venus { --orbit-semi-major: 55px; --orbit-semi-minor: 54.9px; --orbit-offset-x: 0.37px; }
  .orbit--earth { --orbit-semi-major: 75px; --orbit-semi-minor: 74.9px; --orbit-offset-x: 1.3px; }
  .orbit--mars { --orbit-semi-major: 98px; --orbit-semi-minor: 97.1px; --orbit-offset-x: 9.2px; }
  .orbit--jupiter { --orbit-semi-major: 130px; --orbit-semi-minor: 129.5px; --orbit-offset-x: 6.3px; }
  .orbit--saturn { --orbit-semi-major: 165px; --orbit-semi-minor: 164.4px; --orbit-offset-x: 8.6px; }
  .orbit--uranus { --orbit-semi-major: 200px; --orbit-semi-minor: 199.6px; --orbit-offset-x: 9.4px; }
  .orbit--neptune { --orbit-semi-major: 230px; --orbit-semi-minor: 229.8px; --orbit-offset-x: 2.0px; }
  
  .planet--mercury { --planet-size: 10px; }
  .planet--venus { --planet-size: 14px; }
  .planet--earth { --planet-size: 16px; }
  .planet--mars { --planet-size: 12px; }
  .planet--jupiter { --planet-size: 26px; }
  .planet--saturn { --planet-size: 22px; }
  .planet--uranus { --planet-size: 18px; }
  .planet--neptune { --planet-size: 16px; }
  
  .info {
    width: min(85vw, 420px);
    font-size: 12px;
  }
  
  .info__grid {
    font-size: 10px;
    padding: 14px 18px;
    column-gap: 20px;
    row-gap: 10px;
  }
  
  .info__note {
    font-size: 10px;
  }
}

@media (max-width: 500px) {
  .sun { width: 40px; height: 40px; }
  .sun-glow { width: 90px; height: 90px; }
  
  .orbit--mercury { --orbit-semi-major: 30px; --orbit-semi-minor: 29.4px; --orbit-offset-x: 6.2px; }
  .orbit--venus { --orbit-semi-major: 44px; --orbit-semi-minor: 43.9px; --orbit-offset-x: 0.3px; }
  .orbit--earth { --orbit-semi-major: 60px; --orbit-semi-minor: 59.9px; --orbit-offset-x: 1.0px; }
  .orbit--mars { --orbit-semi-major: 78px; --orbit-semi-minor: 77.3px; --orbit-offset-x: 7.3px; }
  .orbit--jupiter { --orbit-semi-major: 104px; --orbit-semi-minor: 103.6px; --orbit-offset-x: 5.1px; }
  .orbit--saturn { --orbit-semi-major: 132px; --orbit-semi-minor: 131.5px; --orbit-offset-x: 6.9px; }
  .orbit--uranus { --orbit-semi-major: 160px; --orbit-semi-minor: 159.7px; --orbit-offset-x: 7.6px; }
  .orbit--neptune { --orbit-semi-major: 184px; --orbit-semi-minor: 183.9px; --orbit-offset-x: 1.6px; }
  
  .planet--mercury { --planet-size: 8px; }
  .planet--venus { --planet-size: 12px; }
  .planet--earth { --planet-size: 13px; }
  .planet--mars { --planet-size: 10px; }
  .planet--jupiter { --planet-size: 22px; }
  .planet--saturn { --planet-size: 18px; }
  .planet--uranus { --planet-size: 15px; }
  .planet--neptune { --planet-size: 14px; }
  
  .planet--saturn .planet__ring {
    border-width: 1.5px;
  }
  
  .info {
    width: min(90vw, 360px);
    font-size: 11px;
    bottom: 16px;
    left: 16px;
  }
  
  .info__grid {
    font-size: 9px;
    padding: 12px 14px;
    column-gap: 16px;
    row-gap: 8px;
  }
  
  .info__grid strong {
    padding: 3px 8px;
  }
  
  .info__note {
    font-size: 9px;
  }
  
  .info__line:first-child {
    font-size: 9px;
  }
}