/* History of the Earth ------------------------------------------------ */

:root {
  --ink:        #eef2f7;
  --ink-dim:    #97a2b2;
  --ink-faint:  #5d6879;
  --bg:         #04060a;
  --rule:       rgba(255,255,255,.13);
  --rule-soft:  rgba(255,255,255,.07);
  --accent:     #7fc6ff;
  --era:        #7fa056;      /* live-updated from JS */
  --serif: "Newsreader", ui-serif, Georgia, "Times New Roman", serif;
  --sans:  "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
  --mono:  "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
  --pad: clamp(18px, 3.4vw, 46px);
  --card-w: clamp(300px, 34vw, 430px);
}

* { box-sizing: border-box; }

html { scroll-behavior: auto; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
  overscroll-behavior-y: none;
}

#gl {
  position: fixed;
  inset: 0;
  width: 100vw;
  height: 100vh;
  height: 100dvh;
  display: block;
  z-index: 0;
}

/* Faint film grain so gradients in the atmosphere do not band */
#grain {
  position: fixed;
  inset: -50%;
  z-index: 1;
  pointer-events: none;
  opacity: .16;
  mix-blend-mode: overlay;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='140' height='140'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.9' numOctaves='3'/%3E%3C/filter%3E%3Crect width='140' height='140' filter='url(%23n)' opacity='.55'/%3E%3C/svg%3E");
}

#scroll-track { position: relative; z-index: 2; pointer-events: none; }

/* ---- Opening title -------------------------------------------------- */

#intro {
  position: fixed;
  inset: 0;
  z-index: 12;
  display: grid;
  place-items: center;
  text-align: center;
  padding: var(--pad);
  pointer-events: none;
  background: radial-gradient(ellipse 90% 70% at 50% 50%, rgba(4,6,10,.82) 0%, rgba(4,6,10,.5) 55%, rgba(4,6,10,0) 100%);
}
.intro-inner { max-width: 40rem; }

.kicker {
  font-family: var(--mono);
  font-size: clamp(9px, 1.05vw, 11.5px);
  letter-spacing: .34em;
  text-transform: uppercase;
  color: var(--ink-faint);
  margin: 0 0 clamp(18px, 3vw, 30px);
}

#intro h1 {
  font-family: var(--serif);
  font-weight: 300;
  font-size: clamp(46px, 9.2vw, 116px);
  line-height: .94;
  letter-spacing: -.025em;
  margin: 0 0 clamp(20px, 3.4vw, 34px);
}
#intro h1 em {
  font-style: italic;
  color: #cfe6ff;
  text-shadow: 0 0 60px rgba(126,190,255,.4);
}

#intro .sub {
  font-family: var(--serif);
  font-size: clamp(14.5px, 1.65vw, 19px);
  line-height: 1.62;
  color: var(--ink-dim);
  margin: 0 auto clamp(34px, 6vw, 58px);
  max-width: 33rem;
  text-wrap: balance;
}

.scroll-cue {
  font-family: var(--mono);
  font-size: 10.5px;
  letter-spacing: .26em;
  text-transform: uppercase;
  color: var(--ink-faint);
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  gap: 14px;
}
.cue-line {
  width: 1px; height: 44px;
  background: linear-gradient(180deg, transparent, var(--ink-faint));
  animation: cue 2.6s ease-in-out infinite;
  transform-origin: top;
}
@keyframes cue {
  0%,100% { transform: scaleY(.35); opacity: .35; }
  50%     { transform: scaleY(1);   opacity: 1; }
}

/* ---- HUD ------------------------------------------------------------ */

#hud {
  position: fixed;
  inset: 0;
  z-index: 10;
  pointer-events: none;
  padding: var(--pad);
  transition: opacity .7s ease;
}
.hidden { opacity: 0 !important; }

#clock {
  position: absolute;
  top: var(--pad);
  left: var(--pad);
}
#clock-value {
  display: flex;
  align-items: baseline;
  gap: .5em;
  flex-wrap: wrap;
}
#clock-num {
  font-family: var(--mono);
  font-weight: 300;
  font-size: clamp(30px, 4.6vw, 58px);
  letter-spacing: -.03em;
  line-height: 1;
  font-variant-numeric: tabular-nums;
  color: #fff;
  text-shadow: 0 2px 30px rgba(0,0,0,.85);
}
#clock-unit {
  font-family: var(--mono);
  font-size: clamp(9.5px, 1.05vw, 11.5px);
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--ink-dim);
}
#clock-era {
  display: flex;
  align-items: center;
  gap: 9px;
  margin-top: 13px;
  font-family: var(--mono);
  font-size: clamp(9.5px, 1vw, 11px);
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--ink-dim);
}
#era-swatch {
  width: 9px; height: 9px;
  border-radius: 2px;
  background: var(--era);
  box-shadow: 0 0 14px var(--era);
  transition: background .6s ease, box-shadow .6s ease;
  flex: none;
}

#metrics {
  position: absolute;
  left: var(--pad);
  bottom: var(--pad);
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--rule-soft);
  border: 1px solid var(--rule-soft);
  width: clamp(230px, 23vw, 288px);
  backdrop-filter: blur(7px);
  -webkit-backdrop-filter: blur(7px);
}
.metric {
  background: rgba(4,7,12,.5);
  padding: 8px 11px 9px;
  display: flex;
  flex-direction: column;
  gap: 3px;
}
.m-key {
  font-family: var(--mono);
  font-size: 8.5px;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--ink-faint);
}
.m-key sub { font-size: .78em; }
.m-val {
  font-family: var(--mono);
  font-size: clamp(11px, 1.2vw, 13px);
  color: var(--ink);
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

/* ---- Narrative cards ------------------------------------------------ */

#cards {
  position: fixed;
  inset: 0;
  z-index: 11;
  pointer-events: none;
  transition: opacity .7s ease;
}

.card {
  position: absolute;
  right: var(--pad);
  top: 50%;
  width: var(--card-w);
  transform: translateY(-50%);
  opacity: 0;
  visibility: hidden;
  will-change: opacity, transform;
}

.card-eon {
  font-family: var(--mono);
  font-size: 9.5px;
  letter-spacing: .24em;
  text-transform: uppercase;
  color: var(--card-era, var(--ink-faint));
  margin: 0 0 12px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.card-eon::before {
  content: "";
  width: 16px; height: 1px;
  background: currentColor;
  flex: none;
}

.card-date {
  font-family: var(--mono);
  font-size: clamp(10px, 1.05vw, 11.5px);
  letter-spacing: .1em;
  color: var(--ink-dim);
  margin: 0 0 8px;
}

.card h2 {
  font-family: var(--serif);
  font-weight: 400;
  font-size: clamp(23px, 2.9vw, 35px);
  line-height: 1.12;
  letter-spacing: -.02em;
  margin: 0 0 15px;
  text-wrap: balance;
  text-shadow: 0 2px 34px rgba(0,0,0,.9);
}

.card p.body {
  font-family: var(--serif);
  font-size: clamp(14px, 1.5vw, 17px);
  line-height: 1.66;
  color: #d3dbe6;
  margin: 0;
  text-shadow: 0 1px 22px rgba(0,0,0,.95);
}

.card .foot {
  margin-top: 18px;
  padding-top: 13px;
  border-top: 1px solid var(--rule-soft);
  display: grid;
  gap: 7px;
}
.card .foot div {
  font-family: var(--mono);
  font-size: 9.8px;
  line-height: 1.62;
  color: var(--ink-faint);
  letter-spacing: .02em;
}
.card .foot .lbl {
  color: var(--ink-faint);
  opacity: .72;
  letter-spacing: .18em;
  text-transform: uppercase;
  font-size: 8.2px;
  display: block;
  margin-bottom: 2px;
}

/* Cards sit on a soft scrim so text stays legible over a bright planet */
#cards::after {
  content: "";
  position: absolute;
  inset: 0 0 0 auto;
  width: min(58vw, calc(var(--card-w) + var(--pad) * 3.4));
  background: linear-gradient(270deg, rgba(4,6,10,.74) 0%, rgba(4,6,10,.44) 46%, rgba(4,6,10,0) 100%);
  pointer-events: none;
  z-index: -1;
}

/* ---- Scrubber ------------------------------------------------------- */

#scrubber {
  position: fixed;
  z-index: 13;
  right: calc(var(--pad) * .42);
  top: 50%;
  transform: translateY(-50%);
  height: min(60vh, 520px);
  width: 26px;
  transition: opacity .7s ease;
}
#scrub-track {
  position: relative;
  height: 100%;
  width: 4px;
  margin-left: 11px;
  background: rgba(255,255,255,.06);
}
#scrub-bands { position: absolute; inset: 0; overflow: hidden; }
.band {
  position: absolute;
  left: 0; right: 0;
  opacity: .5;
  transition: opacity .4s ease;
}
.band.on { opacity: 1; }

#scrub-ticks { position: absolute; inset: 0; }
.tick {
  position: absolute;
  right: 8px;
  transform: translateY(-50%);
  font-family: var(--mono);
  font-size: 8.4px;
  letter-spacing: .1em;
  color: var(--ink-faint);
  white-space: nowrap;
  opacity: .6;
}
.tick::after {
  content: "";
  position: absolute;
  right: -8px; top: 50%;
  width: 5px; height: 1px;
  background: currentColor;
}

#scrub-head {
  position: absolute;
  left: -5px; right: -5px;
  height: 2px;
  background: #fff;
  box-shadow: 0 0 12px rgba(255,255,255,.8);
  will-change: top;
}
/* Only on hover: parked permanently it collides with the narrative card,
   and the main clock already shows the date. */
#scrub-head-label {
  position: absolute;
  right: 16px; top: 50%;
  transform: translateY(-50%);
  font-family: var(--mono);
  font-size: 9px;
  color: #fff;
  white-space: nowrap;
  padding: 3px 7px;
  background: rgba(6,9,15,.9);
  border: 1px solid var(--rule-soft);
  opacity: 0;
  transition: opacity .25s ease;
}
#scrubber:hover #scrub-head-label { opacity: 1; }

/* ---- Tools ---------------------------------------------------------- */

#tools {
  position: fixed;
  z-index: 13;
  left: 50%;
  bottom: calc(var(--pad) * .55);
  transform: translateX(-50%);
  display: flex;
  gap: 8px;
  transition: opacity .7s ease;
}
#tools button {
  font-family: var(--mono);
  font-size: 9.6px;
  letter-spacing: .17em;
  text-transform: uppercase;
  color: var(--ink-dim);
  background: rgba(8,12,19,.62);
  border: 1px solid var(--rule-soft);
  padding: 8px 14px;
  cursor: pointer;
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  transition: color .25s, border-color .25s, background .25s;
}
#tools button:hover { color: #fff; border-color: var(--rule); background: rgba(16,22,32,.8); }

/* ---- Methods modal -------------------------------------------------- */

.modal {
  position: fixed;
  inset: 0;
  z-index: 40;
  background: rgba(2,4,7,.9);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  animation: fade .3s ease;
}
.modal[hidden] { display: none; }
@keyframes fade { from { opacity: 0 } to { opacity: 1 } }

.modal-scroll { height: 100%; overflow-y: auto; -webkit-overflow-scrolling: touch; }
.modal-inner {
  max-width: 40rem;
  margin: 0 auto;
  padding: clamp(48px, 9vw, 96px) var(--pad) clamp(60px, 12vw, 120px);
  position: relative;
}
.modal-close {
  position: fixed;
  top: var(--pad); right: var(--pad);
  width: 40px; height: 40px;
  font-size: 22px;
  line-height: 1;
  color: var(--ink-dim);
  background: rgba(10,14,22,.7);
  border: 1px solid var(--rule-soft);
  cursor: pointer;
}
.modal-close:hover { color: #fff; }

.modal h2 {
  font-family: var(--serif);
  font-weight: 400;
  font-size: clamp(28px, 4.4vw, 42px);
  letter-spacing: -.02em;
  margin: 0 0 22px;
}
.modal h3 {
  font-family: var(--mono);
  font-weight: 400;
  font-size: 10px;
  letter-spacing: .24em;
  text-transform: uppercase;
  color: var(--accent);
  margin: 46px 0 16px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--rule-soft);
}
.modal p, .modal li {
  font-family: var(--serif);
  font-size: 16px;
  line-height: 1.72;
  color: #c3ccda;
}
.modal .lede { font-size: 18.5px; color: var(--ink); }
.modal ul { padding-left: 1.15em; margin: 0; }
.modal li { margin-bottom: 14px; }
.modal strong { color: var(--ink); font-weight: 500; }
.modal em { font-style: italic; }
.colophon {
  margin-top: 44px;
  font-family: var(--mono) !important;
  font-size: 10.5px !important;
  line-height: 1.85 !important;
  color: var(--ink-faint) !important;
}

.noscript {
  position: fixed; inset: 0;
  display: grid; place-items: center;
  padding: 2rem; text-align: center;
  font-family: var(--serif); font-size: 18px; color: var(--ink-dim);
  background: var(--bg); z-index: 99;
}

/* ---- Loading -------------------------------------------------------- */

#boot {
  position: fixed;
  inset: 0;
  z-index: 60;
  display: grid;
  place-items: center;
  background: var(--bg);
  transition: opacity .9s ease;
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: .3em;
  text-transform: uppercase;
  color: var(--ink-faint);
}
#boot.done { opacity: 0; pointer-events: none; }

/* ---- Responsive ----------------------------------------------------- */

/* Narrow screens: the readouts move up under the clock and the card takes
   the whole lower half, inset from the scrubber rail on the right. */
@media (max-width: 900px) {
  :root { --pad: clamp(16px, 4vw, 26px); }

  #metrics {
    top: calc(var(--pad) + 84px);
    bottom: auto;
    left: var(--pad);
    right: calc(var(--pad) + 20px);
    width: auto;
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .metric { padding: 6px 9px 7px; }

  .card {
    top: auto;
    bottom: calc(var(--pad) + 42px);
    left: var(--pad);
    right: calc(var(--pad) + 20px);
    width: auto;
    max-height: 56vh;
    overflow: hidden;
    /* Softens the cut only for the rare entry that overruns; a shallower
       fade than this would blur text that actually fits. */
    -webkit-mask-image: linear-gradient(180deg, #000 0, #000 95%, transparent 100%);
    mask-image: linear-gradient(180deg, #000 0, #000 95%, transparent 100%);
  }
  .card h2 { font-size: clamp(21px, 5.8vw, 30px); margin-bottom: 11px; }
  .card p.body { font-size: 14px; line-height: 1.55; }
  .card .foot { display: none; }
  .card-eon { font-size: 8.6px; margin-bottom: 9px; }
  .card-date { font-size: 10px; margin-bottom: 6px; }

  #cards::after {
    inset: auto 0 0 0; width: auto; height: 76vh;
    background: linear-gradient(0deg, rgba(4,6,10,.94) 0%, rgba(4,6,10,.78) 40%, rgba(4,6,10,0) 100%);
  }

  #scrubber { height: 46vh; right: 2px; width: 18px; }
  #scrub-track { margin-left: 7px; width: 3px; }
  #scrub-head-label, .tick { display: none; }

  #clock-num { font-size: clamp(26px, 8vw, 40px); }
  #clock-era { margin-top: 9px; }
  #tools { bottom: 6px; }
  #tools button { font-size: 8.4px; padding: 6px 9px; letter-spacing: .12em; }
}

@media (max-width: 560px) {
  .card p.body { font-size: 13.2px; line-height: 1.52; }
  .card { max-height: 54vh; }
  #metrics { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .metric:nth-child(n+5) { display: none; }   /* keep O2, CO2, surface, day */
}

/* Short landscape phones: there is no room for a metrics panel at all. */
@media (max-height: 520px) and (max-width: 900px) {
  #metrics { display: none; }
  .card { max-height: 62vh; bottom: calc(var(--pad) + 34px); }
}

@media (prefers-reduced-motion: reduce) {
  .cue-line { animation: none; opacity: .7; }
}