:root {
  --bg: #090c14;
  --panel: #10152444;
  --line: #232a3d;
  --text: #eef1f7;
  --text-muted: #8a92ab;
  --amber: #e8b657;
  --teal: #4fc7a3;
  --rose: #b56271;
  --green-bright: #5edb8a;
  --green-dim: #1a3a2a;

  --font-display: "Fraunces", serif;
  --font-mono: "IBM Plex Mono", monospace;
  --font-body: "Inter", sans-serif;
}

* { box-sizing: border-box; }

@media (prefers-reduced-motion: reduce) {
  * { animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; }
}

html, body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  scroll-behavior: smooth;
}

/* ---------- Fixed starfield ---------- */

#stage {
  position: fixed;
  inset: 0;
  z-index: 0;
}

#sky {
  width: 100%;
  height: 100%;
}

.dot {
  fill: #3a4054;
  transition: fill 0.6s ease, opacity 0.6s ease, r 0.6s ease;
}

.dot.predicted {
  fill: var(--amber);
}

.dot.correct {
  fill: var(--teal);
}

.dot.false-alarm {
  fill: #3a4054;
  opacity: 0.35;
}

.axis-label {
  position: absolute;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.04em;
  color: var(--text-muted);
  text-transform: uppercase;
}

#axis-x-label, #axis-y-label { display: none; }

/* ---------- Mission log rail ---------- */

#log {
  position: fixed;
  top: 2.5rem;
  right: 3rem;
  z-index: 5;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  min-width: 15rem;
}

.log-heading {
  color: var(--text-muted);
  letter-spacing: 0.12em;
  margin-bottom: 0.9rem;
  font-size: 0.68rem;
}

.log-row {
  display: grid;
  grid-template-columns: 1.6rem 1fr auto;
  gap: 0.6rem;
  align-items: baseline;
  padding: 0.5rem 0;
  border-top: 1px solid var(--line);
  color: var(--text-muted);
  transition: color 0.4s ease;
}

.log-row.active {
  color: var(--text);
}

.log-index { color: #4a5170; }
.log-row.active .log-index { color: var(--amber); }
.log-row[data-row="2"].active .log-index { color: var(--teal); }

.log-count {
  font-variant-numeric: tabular-nums;
  color: var(--text);
}

/* ---------- Scroll steps ---------- */

main {
  position: relative;
  z-index: 2;
}

.step, .step-end {
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding: 0 3rem;
}

.card {
  max-width: 30rem;
  background: linear-gradient(180deg, rgba(9,12,20,0.92), rgba(9,12,20,0.75));
  backdrop-filter: blur(6px);
  border-left: 2px solid var(--amber);
  padding: 1.8rem 2rem;
}

.card-wide {
  max-width: 42rem;
}

.step[data-step="2"] .card { border-left-color: var(--teal); }
.step[data-step="3"] .card { border-left-color: var(--green-bright); }
.step[data-step="4"] .card { border-left-color: var(--text-muted); }

.eyebrow {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin: 0 0 0.8rem;
}

h1 {
  font-family: var(--font-display);
  font-weight: 500;
  font-size: clamp(1.8rem, 3.4vw, 2.6rem);
  line-height: 1.15;
  margin: 0 0 1rem;
}

.lede {
  font-size: 1rem;
  line-height: 1.6;
  color: var(--text-muted);
  margin: 0;
}

.lede strong {
  color: var(--text);
}

.step-end .card { border-left-color: var(--line); }

.step-intro .card { border-left-color: var(--text-muted); }

.lede code {
  font-family: var(--font-mono);
  font-size: 0.82em;
  padding: 0.1rem 0.4rem;
  background: rgba(255,255,255,0.06);
  border-radius: 3px;
  color: var(--amber);
  word-break: break-all;
}

/* ---------- Detail boxes ---------- */

.detail-box {
  margin-top: 1.2rem;
  padding: 1rem 1.2rem;
  background: rgba(255, 255, 255, 0.03);
  border-left: 2px solid var(--line);
  border-radius: 0 4px 4px 0;
}

.detail-title {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--amber);
  margin: 0 0 0.4rem;
}

.detail-text {
  font-size: 0.88rem;
  line-height: 1.55;
  color: var(--text-muted);
  margin: 0;
}

.detail-text em {
  color: var(--text);
  font-style: normal;
  font-weight: 500;
}

/* ---------- Code blocks ---------- */

.code-block {
  margin-top: 1.2rem;
  border: 1px solid var(--line);
  border-radius: 6px;
  overflow: hidden;
}

.code-header {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-muted);
  padding: 0.5rem 1rem;
  background: rgba(255,255,255,0.03);
  border-bottom: 1px solid var(--line);
}

.code-block pre {
  margin: 0;
  padding: 1rem;
  overflow-x: auto;
  background: rgba(0,0,0,0.25);
}

.code-block code {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  line-height: 1.65;
  color: var(--text-muted);
  white-space: pre;
}

/* ---------- Feature tags ---------- */

.feature-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 1.2rem;
}

.feature-tag {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.04em;
  padding: 0.35rem 0.7rem;
  border: 1px solid var(--line);
  border-radius: 3px;
  color: var(--text-muted);
  transition: border-color 0.3s ease, color 0.3s ease;
}

.feature-tag:hover {
  border-color: var(--amber);
  color: var(--amber);
}

.tag-var {
  color: var(--amber);
  margin-right: 0.3rem;
  font-weight: 500;
}

/* ---------- Confusion Matrix ---------- */

.matrix-container {
  margin-top: 1.5rem;
}

.matrix-axis-label {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-muted);
  text-align: center;
}

.matrix-axis-top {
  margin-bottom: 0.6rem;
}

.matrix-wrapper {
  display: flex;
  align-items: center;
  gap: 0.8rem;
}

.matrix-axis-left,
.matrix-axis-right {
  writing-mode: vertical-rl;
  text-orientation: mixed;
  transform: rotate(180deg);
  white-space: nowrap;
  font-size: 0.6rem;
}

.matrix-axis-right {
  writing-mode: vertical-lr;
  transform: none;
}

.matrix-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  grid-template-rows: 1fr 1fr;
  gap: 4px;
  flex: 1;
  max-width: 320px;
}

.matrix-cell {
  position: relative;
  aspect-ratio: 1.3;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  border-radius: 4px;
  cursor: pointer;
  transition: transform 0.25s ease, box-shadow 0.25s ease, filter 0.25s ease;
}

.matrix-cell:hover {
  transform: scale(1.06);
  z-index: 2;
  box-shadow: 0 0 20px rgba(0,0,0,0.5);
}

.matrix-value {
  font-family: var(--font-mono);
  font-size: 1.6rem;
  font-weight: 600;
  color: var(--text);
  line-height: 1;
}

.matrix-label {
  font-family: var(--font-mono);
  font-size: 0.55rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.6);
  margin-top: 0.3rem;
  text-align: center;
}

/* Cell colors */
.matrix-cell.tn {
  background: rgba(26, 58, 42, 0.6);
  border: 1px solid rgba(79, 199, 163, 0.15);
}
.matrix-cell.tp {
  background: rgba(79, 199, 163, 0.25);
  border: 1px solid rgba(79, 199, 163, 0.5);
}
.matrix-cell.fp {
  background: rgba(232, 182, 87, 0.15);
  border: 1px solid rgba(232, 182, 87, 0.35);
}
.matrix-cell.fn {
  background: rgba(181, 98, 113, 0.15);
  border: 1px solid rgba(181, 98, 113, 0.35);
}

.matrix-cell.tn:hover { background: rgba(26, 58, 42, 0.9); }
.matrix-cell.tp:hover { background: rgba(79, 199, 163, 0.4); }
.matrix-cell.fp:hover { background: rgba(232, 182, 87, 0.3); }
.matrix-cell.fn:hover { background: rgba(181, 98, 113, 0.3); }

/* Tooltips */
.matrix-tooltip {
  position: absolute;
  bottom: calc(100% + 10px);
  left: 50%;
  transform: translateX(-50%);
  width: 220px;
  padding: 0.8rem 1rem;
  background: rgba(16, 21, 36, 0.96);
  backdrop-filter: blur(8px);
  border: 1px solid var(--line);
  border-radius: 6px;
  font-family: var(--font-body);
  font-size: 0.78rem;
  line-height: 1.5;
  color: var(--text-muted);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s ease, transform 0.2s ease;
  transform: translateX(-50%) translateY(4px);
  z-index: 10;
}

.matrix-tooltip strong {
  color: var(--text);
  display: block;
  margin-bottom: 0.3rem;
}

.matrix-cell:hover .matrix-tooltip {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* Bottom row tooltips flip below */
.matrix-cell.fn .matrix-tooltip,
.matrix-cell.tp .matrix-tooltip {
  bottom: auto;
  top: calc(100% + 10px);
}

/* ---------- Metrics row ---------- */

.metric-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1rem;
  margin-top: 1.5rem;
}

.metric {
  text-align: center;
  padding: 0.8rem 0.4rem;
  border-top: 1px solid var(--line);
}

.metric-value {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text);
  font-variant-numeric: tabular-nums;
}

.metric-label {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--amber);
  margin-top: 0.2rem;
}

.metric-detail {
  font-size: 0.72rem;
  line-height: 1.4;
  color: var(--text-muted);
  margin-top: 0.3rem;
}

/* ---------- Pipeline ---------- */

.pipeline {
  margin-top: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 0;
}

.pipeline-step {
  display: flex;
  gap: 1rem;
  align-items: flex-start;
}

.pipeline-number {
  flex-shrink: 0;
  width: 2rem;
  height: 2rem;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  border: 1.5px solid var(--amber);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--amber);
}

.pipeline-content h3 {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text);
  margin: 0.2rem 0 0.3rem;
}

.pipeline-content p {
  font-size: 0.85rem;
  line-height: 1.5;
  color: var(--text-muted);
  margin: 0;
}

.pipeline-content code {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  padding: 0.1rem 0.35rem;
  background: rgba(255,255,255,0.06);
  border-radius: 3px;
  color: var(--amber);
}

.pipeline-connector {
  width: 1.5px;
  height: 1.2rem;
  background: var(--line);
  margin-left: 0.95rem;
}

/* ---------- Animations ---------- */

@keyframes fadeSlideUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

.matrix-cell {
  opacity: 0;
  animation: fadeSlideUp 0.5s ease forwards;
}

.matrix-cell.tn { animation-delay: 0.1s; }
.matrix-cell.fp { animation-delay: 0.25s; }
.matrix-cell.fn { animation-delay: 0.4s; }
.matrix-cell.tp { animation-delay: 0.55s; }

.metric {
  opacity: 0;
  animation: fadeSlideUp 0.4s ease forwards;
}

.metric:nth-child(1) { animation-delay: 0.6s; }
.metric:nth-child(2) { animation-delay: 0.72s; }
.metric:nth-child(3) { animation-delay: 0.84s; }
.metric:nth-child(4) { animation-delay: 0.96s; }

/* ---------- Mobile ---------- */

@media (max-width: 720px) {
  #log { display: none; }
  .step, .step-end { padding: 0 1.2rem; }
  .card { max-width: none; }
  .card-wide { max-width: none; }
  #axis-x-label, #axis-y-label { display: none; }

  .metric-row {
    grid-template-columns: repeat(2, 1fr);
  }

  .matrix-grid {
    max-width: 260px;
  }

  .matrix-value {
    font-size: 1.2rem;
  }

  .matrix-tooltip {
    width: 180px;
    font-size: 0.72rem;
  }

  .matrix-axis-left,
  .matrix-axis-right {
    display: none;
  }
}