:root {
  --ink: #0f1412;
  --panel: #171e1b;
  --panel-2: #1e2723;
  --line: #2c3933;
  --muted: #93a59b;
  --text: #e7efe9;
  --accent: #c8f26a;
  --accent-dim: #8fb83f;
  --prompt: #7fd4c3;
  --warn: #ffb454;
  --radius: 6px;
  --max: 920px;
  --font-display: "Syne", sans-serif;
  --font-body: "IBM Plex Sans", system-ui, sans-serif;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--text);
  font-family: var(--font-body);
  font-size: 1.05rem;
  line-height: 1.65;
  background: var(--ink);
}

.page-bg {
  position: fixed;
  inset: 0;
  z-index: -1;
  background:
    radial-gradient(ellipse 80% 50% at 10% -10%, rgba(200, 242, 106, 0.12), transparent 55%),
    radial-gradient(ellipse 60% 40% at 100% 20%, rgba(127, 212, 195, 0.08), transparent 50%),
    linear-gradient(180deg, #121916 0%, var(--ink) 40%, #0c100e 100%);
}

.page-bg::after {
  content: "";
  position: absolute;
  inset: 0;
  opacity: 0.35;
  background-image:
    linear-gradient(rgba(200, 242, 106, 0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(200, 242, 106, 0.03) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.55), transparent 70%);
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 0.75rem 1.25rem;
  backdrop-filter: blur(14px);
  background: rgba(15, 20, 18, 0.82);
  border-bottom: 1px solid var(--line);
}

.brand-mark {
  flex: 0 0 auto;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1rem;
  letter-spacing: 0.08em;
  color: var(--ink);
  background: var(--accent);
  padding: 0.35rem 0.55rem;
  border-radius: 4px;
  text-decoration: none;
}

.section-nav {
  display: flex;
  gap: 0.35rem;
  overflow-x: auto;
  scrollbar-width: none;
  -ms-overflow-style: none;
}

.section-nav::-webkit-scrollbar {
  display: none;
}

.section-nav a {
  flex: 0 0 auto;
  color: var(--muted);
  font-size: 0.82rem;
  font-weight: 500;
  padding: 0.4rem 0.65rem;
  border-radius: 999px;
  text-decoration: none;
  transition: color 0.2s ease, background 0.2s ease;
}

.section-nav a:hover,
.section-nav a.is-active {
  color: var(--ink);
  background: var(--accent);
  text-decoration: none;
}

main {
  width: min(100% - 2rem, var(--max));
  margin: 0 auto;
  padding-bottom: 4rem;
}

.hero {
  padding: clamp(3.5rem, 10vw, 6.5rem) 0 2.5rem;
  animation: rise 0.7s ease both;
}

.hero-meta {
  margin: 0 0 1rem;
  color: var(--muted);
  font-size: 0.95rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.hero h1 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(2.6rem, 9vw, 5rem);
  line-height: 0.95;
  letter-spacing: -0.03em;
  color: var(--text);
}

.hero-lead {
  max-width: 38rem;
  margin: 1.5rem 0 0;
  color: #c5d4cb;
  font-size: 1.12rem;
}

.hero-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 2rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.8rem 1.15rem;
  border-radius: var(--radius);
  font-weight: 600;
  font-size: 0.95rem;
  text-decoration: none;
  transition: transform 0.2s ease, background 0.2s ease, color 0.2s ease;
}

.btn:hover {
  transform: translateY(-1px);
  text-decoration: none;
}

.btn-primary {
  background: var(--accent);
  color: var(--ink);
}

.btn-primary:hover {
  background: #d7f88a;
}

.btn-ghost {
  border: 1px solid var(--line);
  color: var(--text);
  background: transparent;
}

.btn-ghost:hover {
  border-color: var(--accent-dim);
  color: var(--accent);
}

.how-to {
  padding: 1.5rem 0 2.5rem;
  border-top: 1px solid var(--line);
  animation: rise 0.7s ease 0.1s both;
}

.how-to h2,
.block h2,
.checklist h2 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.5rem, 3vw, 2rem);
  letter-spacing: -0.02em;
}

.how-to p {
  margin: 0.85rem 0 0;
  max-width: 42rem;
  color: #c5d4cb;
}

.prompt-chip,
.prompt {
  color: var(--prompt);
  font-style: italic;
}

.block {
  padding: 2.75rem 0;
  border-top: 1px solid var(--line);
  animation: rise 0.6s ease both;
}

.block-head {
  display: flex;
  align-items: baseline;
  gap: 0.85rem;
  margin-bottom: 1rem;
}

.block-num {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 0.95rem;
  color: var(--accent);
  letter-spacing: 0.08em;
}

.block-intro {
  margin: 0 0 1.5rem;
  color: #c5d4cb;
  max-width: 42rem;
}

.block h3 {
  margin: 2rem 0 0.75rem;
  font-family: var(--font-display);
  font-size: 1.15rem;
  font-weight: 700;
}

.callout,
.answer-box,
.example,
.formula-panel {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.15rem 1.25rem;
  margin: 1rem 0;
}

.callout {
  border-left: 3px solid var(--accent);
}

.callout-label,
.answer-label,
.example-label {
  margin: 0 0 0.4rem;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
}

.callout p:last-child,
.answer-box p:last-child,
.example p:last-child {
  margin: 0;
}

.example {
  background: transparent;
  border-style: dashed;
}

.probe-list,
.rules-list {
  margin: 0;
  padding-left: 1.2rem;
  color: #c5d4cb;
}

.probe-list li,
.rules-list li {
  margin: 0.45rem 0;
}

.probe-list li::marker {
  content: "→ ";
  color: var(--accent);
}

.priority-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.75rem;
  margin: 0 0 1.5rem;
}

.priority-grid article {
  background: var(--panel-2);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1rem;
}

.priority-grid strong {
  display: block;
  margin-bottom: 0.35rem;
  font-family: var(--font-display);
  font-size: 0.95rem;
}

.priority-grid p {
  margin: 0;
  color: var(--muted);
  font-size: 0.92rem;
}

.table-wrap {
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
}

table {
  width: 100%;
  border-collapse: collapse;
  min-width: 640px;
  font-size: 0.95rem;
}

th,
td {
  padding: 0.85rem 1rem;
  text-align: left;
  vertical-align: top;
  border-bottom: 1px solid var(--line);
}

th {
  background: var(--panel-2);
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

tr:last-child td {
  border-bottom: none;
}

.total-row td {
  font-weight: 700;
  background: rgba(200, 242, 106, 0.04);
}

.rule {
  margin: 1.25rem 0 0;
  padding: 0.9rem 1rem;
  border-radius: var(--radius);
  background: rgba(255, 180, 84, 0.08);
  border: 1px solid rgba(255, 180, 84, 0.25);
  color: #f0d8b0;
}

.rule strong {
  color: var(--warn);
}

.math {
  font-family: var(--font-display);
  font-size: 1.35rem;
  letter-spacing: 0.02em;
  color: var(--accent);
  margin: 0.5rem 0 1rem;
}

.checklist {
  margin-top: 1rem;
  padding: 2rem 1.35rem;
  border: 1px solid var(--line);
  border-radius: calc(var(--radius) + 2px);
  background:
    linear-gradient(135deg, rgba(200, 242, 106, 0.08), transparent 45%),
    var(--panel);
}

.checklist ul {
  list-style: none;
  margin: 1.25rem 0 0;
  padding: 0;
}

.checklist li {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  margin: 0.7rem 0;
  color: #d5e2d9;
}

.box {
  flex: 0 0 auto;
  width: 1.1rem;
  height: 1.1rem;
  margin-top: 0.3rem;
  border: 1.5px solid var(--accent);
  border-radius: 3px;
  background: rgba(200, 242, 106, 0.08);
}

.checklist-outro {
  margin: 1.5rem 0 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--accent);
}

.site-footer {
  width: min(100% - 2rem, var(--max));
  margin: 0 auto 3rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.95rem;
}

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

@keyframes rise {
  from {
    opacity: 0;
    transform: translateY(14px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 800px) {
  .priority-grid {
    grid-template-columns: 1fr;
  }

  .site-header {
    flex-direction: column;
    align-items: flex-start;
  }

  .section-nav {
    width: 100%;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .hero,
  .how-to,
  .block,
  .btn {
    animation: none;
    transition: none;
  }
}