:root {
  --bg: #0b0d11;
  --bg-soft: #0f1116;
  --fg: #e8ecef;
  --fg-mid: #a6adb5;
  --fg-dim: #6b7079;
  --fg-faint: #383c44;
  --border: #1b1e24;
  --border-bright: #2a2e36;
  --accent: #ffffff;
  --code-bg: #0f1218;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

html,
body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: "JetBrains Mono", "Noto Sans Mono", ui-monospace, SFMono-Regular,
    Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
  font-weight: 400;
  font-size: 15px;
  line-height: 1.7;
  letter-spacing: 0.01em;
}

body {
  min-height: 100vh;
  overflow-x: hidden;
}

#topology {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  opacity: 0.35;
}

main {
  position: relative;
  z-index: 1;
}

/* ---------------------------------------------------------------- topbar */

.topbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 10;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 28px;
  font-size: 11px;
  letter-spacing: 0.22em;
  color: var(--fg-dim);
  background: linear-gradient(
    180deg,
    rgba(11, 13, 17, 0.92) 0%,
    rgba(11, 13, 17, 0.6) 70%,
    rgba(11, 13, 17, 0)
  );
  pointer-events: none;
}

.topbar-left,
.topbar-right {
  pointer-events: auto;
}

.lang-btn {
  background: none;
  border: none;
  color: var(--fg-dim);
  font: inherit;
  letter-spacing: 0.22em;
  padding: 4px 6px;
  cursor: pointer;
  transition: color 0.2s ease;
}

.lang-btn:hover,
.lang-btn[aria-current="true"] {
  color: var(--fg);
}

.lang-btn[aria-current="true"] {
  text-decoration: underline;
  text-underline-offset: 4px;
}

.sep {
  color: var(--fg-faint);
  padding: 0 2px;
}

/* ---------------------------------------------------------------- hero */

.hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 96px 28px 48px;
  text-align: center;
  position: relative;
}

.ascii-art {
  margin: 0 0 40px;
  font-size: 10px;
  line-height: 1.1;
  color: var(--fg-mid);
  letter-spacing: 0;
  white-space: pre;
  font-variant-ligatures: none;
  user-select: none;
  pointer-events: none;
  opacity: 0.85;
  text-shadow: 0 0 12px rgba(255, 255, 255, 0.04);
}

@media (min-width: 900px) {
  .ascii-art {
    font-size: 11px;
  }
}

.hero-text {
  max-width: 760px;
}

.hero-text .title {
  margin: 0 0 14px;
  font-size: 38px;
  font-weight: 500;
  letter-spacing: 0.28em;
  color: var(--fg);
  line-height: 1;
}

.hero-text .subtitle {
  margin: 0 0 28px;
  font-size: 13px;
  letter-spacing: 0.32em;
  color: var(--fg-mid);
  text-transform: uppercase;
}

.hero-text .hook {
  margin: 0 auto 22px;
  max-width: 720px;
  font-size: 19px;
  line-height: 1.55;
  color: var(--fg);
  font-weight: 400;
  letter-spacing: 0.01em;
}

.hero-text .tagline {
  margin: 0 auto 36px;
  max-width: 640px;
  font-size: 14px;
  color: var(--fg-mid);
  line-height: 1.75;
}

@media (min-width: 900px) {
  .hero-text .hook {
    font-size: 22px;
  }
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  justify-content: center;
  align-items: center;
}

.cta-row-end {
  margin-top: 36px;
  justify-content: flex-start;
}

.cta {
  display: inline-block;
  padding: 12px 22px;
  border: 1px solid var(--border-bright);
  color: var(--fg);
  text-decoration: none;
  letter-spacing: 0.18em;
  font-size: 12px;
  transition: border-color 0.2s ease, background 0.2s ease, color 0.2s ease;
  background: rgba(0, 0, 0, 0.4);
  white-space: nowrap;
}

.cta:hover {
  border-color: var(--fg);
  color: var(--fg);
  background: rgba(255, 255, 255, 0.04);
}

.cta-secondary {
  background: transparent;
  border-color: var(--border);
  color: var(--fg-mid);
}

.cta-secondary:hover {
  color: var(--fg);
  border-color: var(--border-bright);
}

.scroll-hint {
  margin-top: 56px;
  font-size: 11px;
  letter-spacing: 0.3em;
  color: var(--fg-faint);
}

/* ---------------------------------------------------------------- section */

.section {
  max-width: 820px;
  margin: 0 auto;
  padding: 120px 28px 80px;
}

.section-meta {
  display: flex;
  gap: 16px;
  align-items: baseline;
  color: var(--fg-dim);
  font-size: 11px;
  letter-spacing: 0.28em;
  margin-bottom: 8px;
}

.section-num {
  color: var(--fg);
}

.section-label::before {
  content: "//  ";
  color: var(--fg-faint);
}

.section-title {
  margin: 0 0 36px;
  font-size: 22px;
  font-weight: 500;
  letter-spacing: 0.18em;
  color: var(--fg);
}

.prose p {
  margin: 0 0 16px;
  color: var(--fg);
}

.prose p.dim {
  color: var(--fg-mid);
}

.prose .highlight {
  color: var(--fg);
  border-bottom: 1px solid var(--border-bright);
  padding-bottom: 1px;
}

/* ---------------------------------------------------------------- kv list (loop steps) */

.kv-list {
  list-style: none;
  padding: 0;
  margin: 0;
  border-top: 1px solid var(--border);
}

.kv-list li {
  display: grid;
  grid-template-columns: 110px 1fr;
  gap: 20px;
  padding: 14px 0;
  border-bottom: 1px solid var(--border);
}

.kv-list .k {
  color: var(--fg-mid);
  letter-spacing: 0.16em;
  font-size: 13px;
}

.kv-list .v {
  color: var(--fg);
}

@media (max-width: 640px) {
  .kv-list li {
    grid-template-columns: 1fr;
    gap: 4px;
  }
}

/* ---------------------------------------------------------------- rules / invariants list */

.rule-list {
  list-style: none;
  padding: 0;
  margin: 0;
  counter-reset: rule;
}

.rule-list li {
  padding: 18px 0;
  border-bottom: 1px solid var(--border);
}

.rule-list li:first-child {
  border-top: 1px solid var(--border);
}

.rule-list .rule-head {
  color: var(--fg);
  margin-bottom: 6px;
}

.rule-list .rule-body {
  color: var(--fg-mid);
  padding-left: 16px;
}

.rule-list .rule-body div {
  padding: 2px 0;
}

.callout {
  margin-top: 28px;
  padding: 18px 20px;
  border: 1px solid var(--border-bright);
  background: rgba(255, 255, 255, 0.015);
}

.callout-head {
  color: var(--fg);
  margin-bottom: 6px;
  letter-spacing: 0.14em;
  font-size: 12px;
}

.callout-body {
  color: var(--fg-mid);
  font-size: 13px;
  line-height: 1.7;
}

.callout-link {
  display: inline-block;
  margin-top: 14px;
  color: var(--fg);
  text-decoration: none;
  font-size: 12px;
  letter-spacing: 0.14em;
  border-bottom: 1px solid var(--border-bright);
  padding-bottom: 2px;
}

.callout-link:hover {
  border-bottom-color: var(--fg);
}

/* ---------------------------------------------------------------- allocation (v1.0 stats) */

.allocation-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
  margin-bottom: 28px;
}

.allocation-cell {
  border: 1px solid var(--border);
  padding: 22px 20px;
  background: rgba(255, 255, 255, 0.01);
}

.allocation-key {
  color: var(--fg-mid);
  font-size: 11px;
  letter-spacing: 0.22em;
  margin-bottom: 14px;
  text-transform: uppercase;
}

.allocation-value {
  color: var(--fg);
  font-size: 36px;
  font-weight: 500;
  letter-spacing: 0.02em;
  margin-bottom: 14px;
  line-height: 1;
}

.allocation-note {
  color: var(--fg-mid);
  font-size: 12px;
  line-height: 1.6;
}

.allocation-summary {
  color: var(--fg-mid);
  font-size: 13px;
  line-height: 1.8;
  margin: 0;
}

@media (max-width: 640px) {
  .allocation-grid {
    grid-template-columns: 1fr;
  }
}

/* ---------------------------------------------------------------- get started / code */

.submit-intro {
  color: var(--fg-mid);
  margin: 0 0 28px;
  font-size: 14px;
  line-height: 1.75;
}

.code-caption {
  color: var(--fg-dim);
  font-size: 12px;
  letter-spacing: 0.14em;
  margin: 24px 0 8px;
  text-transform: uppercase;
}

.code-caption::before {
  content: "//  ";
  color: var(--fg-faint);
}

.code-block {
  margin: 0;
  padding: 16px 18px;
  background: var(--code-bg);
  border: 1px solid var(--border);
  color: var(--fg);
  font-family: inherit;
  font-size: 13px;
  line-height: 1.65;
  overflow-x: auto;
  white-space: pre;
}

.code-block code {
  font: inherit;
  color: inherit;
}

/* ---------------------------------------------------------------- footer */

.footer {
  border-top: 1px solid var(--border);
  margin-top: 40px;
  padding: 28px 28px 36px;
  position: relative;
  z-index: 1;
}

.footer-row {
  max-width: 820px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
  color: var(--fg-dim);
  font-size: 11px;
  letter-spacing: 0.22em;
}

@media (max-width: 640px) {
  .footer-row {
    flex-direction: column;
  }
}