:root {
  --ink: #17181A;
  --ink-soft: #52565B;
  --paper: #FFFFFF;
  --paper-alt: #F2F1ED;
  --border: #DEDCD4;
  --scope-bg: #14171A;
  --scope-grid: #262B30;
  --scope-axis: #3A3F45;
  --scope-label: #8B9096;
  --signal: #37B6A6;
  --alias: #E2574C;
  --sample: #F2B705;
  --ok: #1E8E5A;
  --radius: 6px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: 'IBM Plex Sans', 'IBM Plex Sans Thai', 'Noto Sans Thai',
               'Thonburi', system-ui, sans-serif;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

.mono { font-family: 'IBM Plex Mono', monospace; }

:lang(th) { line-height: 1.75; }

.page {
  max-width: 680px;
  margin: 0 auto;
  padding: 3rem 1.5rem 4rem;
}

.hero { margin-bottom: 2.5rem; }

.hero-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  margin-bottom: 0.5rem;
}

.kicker {
  font-size: 0.8125rem;
  color: var(--ink-soft);
  margin: 0;
}

.lang-switch {
  display: flex;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  flex-shrink: 0;
}

.lang-switch a {
  display: flex;
  align-items: center;
  min-height: 2.25rem;
  padding: 0.25rem 0.875rem;
  font-size: 0.8125rem;
  line-height: 1.4;
  color: var(--ink-soft);
  text-decoration: none;
  background: var(--paper);
  transition: background-color 0.15s ease, color 0.15s ease;
}

.lang-switch a + a { border-left: 1px solid var(--border); }
.lang-switch a:hover { background: var(--paper-alt); color: var(--ink); }

.lang-switch a.is-active {
  background: var(--ink);
  color: var(--paper);
  font-weight: 500;
}

.lang-switch a:focus-visible {
  outline: 2px solid var(--signal);
  outline-offset: -2px;
}

h1 {
  font-size: clamp(1.9rem, 5vw, 2.5rem);
  line-height: 1.15;
  font-weight: 600;
  margin: 0 0 1rem;
}

.lede {
  font-size: 1.0625rem;
  color: var(--ink-soft);
  max-width: 58ch;
  margin: 0;
}

h2 {
  font-size: 1.375rem;
  font-weight: 600;
  margin: 0 0 0.75rem;
}

.scope-section {
  background: var(--paper-alt);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.5rem;
  margin-bottom: 3rem;
}

.controls { display: flex; flex-direction: column; gap: 1.25rem; margin-bottom: 1.5rem; }

.control-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  font-size: 0.9375rem;
  margin-bottom: 0.375rem;
}

.control-row label { color: var(--ink-soft); }

.readout { font-weight: 500; }

input[type="range"] {
  width: 100%;
  accent-color: var(--signal);
}

.scope {
  position: relative;
  background: var(--scope-bg);
  background-image:
    linear-gradient(var(--scope-grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--scope-grid) 1px, transparent 1px);
  background-size: 12.5% 20%;
  border-radius: var(--radius);
  height: 220px;
  overflow: hidden;
}

.scope canvas { position: absolute; inset: 0; width: 100%; height: 100%; display: block; }

.scope-label {
  position: absolute;
  top: 8px;
  left: 10px;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.6875rem;
  color: var(--scope-label);
  z-index: 2;
}

.scope-axis {
  position: absolute;
  bottom: 6px;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.6875rem;
  color: var(--scope-label);
  z-index: 2;
}
.scope-axis-left { left: 10px; }
.scope-axis-right { right: 10px; }

.status-panel {
  margin-top: 1.25rem;
  padding: 0.875rem 1rem;
  background: var(--paper);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.status-row {
  display: flex;
  justify-content: space-between;
  font-size: 0.9375rem;
  margin-bottom: 0.375rem;
  color: var(--ink-soft);
}

.status-msg { font-weight: 500; }
.status-msg.ok { color: var(--ok); }
.status-msg.warn { color: var(--alias); }

.legend {
  display: flex;
  gap: 1.25rem;
  flex-wrap: wrap;
  margin-top: 1rem;
  font-size: 0.8125rem;
  color: var(--ink-soft);
}

.legend-item { display: flex; align-items: center; gap: 6px; }
.legend-alias { display: none; }
.legend-alias.show { display: flex; }

.swatch { width: 14px; height: 2px; display: inline-block; }
.swatch-signal { background: var(--signal); }
.swatch-alias { border-top: 2px dashed var(--alias); }
.swatch-sample { width: 8px; height: 8px; border-radius: 50%; background: var(--sample); }

.reference { margin-bottom: 2.5rem; }
.reference p { color: var(--ink-soft); margin: 0 0 1rem; max-width: 62ch; }

.formula {
  background: var(--paper-alt);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem 1.25rem;
  margin: 1.25rem 0;
}
.formula-line { display: flex; gap: 0.75rem; align-items: baseline; padding: 0.2rem 0; font-size: 0.9375rem; }
.formula-cond { color: var(--ink-soft); font-size: 0.8125rem; }

.examples { list-style: none; padding: 0; margin: 0; display: flex; flex-direction: column; gap: 0.875rem; }
.examples li { color: var(--ink-soft); border-left: 2px solid var(--border); padding-left: 0.875rem; }
.example-term { color: var(--ink); font-weight: 500; }

.consequences {
  list-style: none;
  padding: 0;
  margin: 1.5rem 0 0;
  counter-reset: hw;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.consequences li {
  counter-increment: hw;
  position: relative;
  padding-left: 2.375rem;
}

.consequences li::before {
  content: counter(hw);
  position: absolute;
  left: 0;
  top: 0.125rem;
  width: 1.625rem;
  height: 1.625rem;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.75rem;
  color: var(--ink-soft);
  background: var(--paper-alt);
  border: 1px solid var(--border);
  border-radius: 50%;
}

.consequences h3 {
  font-size: 1rem;
  font-weight: 600;
  line-height: 1.45;
  margin: 0 0 0.375rem;
}

.reference .consequences p { margin: 0; }

.footer {
  border-top: 1px solid var(--border);
  padding-top: 1.25rem;
  font-size: 0.8125rem;
  color: var(--ink-soft);
}

.footer p { margin: 0; }

/* Links back to the site index, so this page is not an island for readers
   or for crawlers. */
.footer-home {
  margin-top: 0.5rem !important;
  font-family: 'IBM Plex Mono', monospace;
}

.footer-home a {
  color: var(--ink-soft);
  text-decoration: none;
}

.footer-home a:hover { color: var(--ink); }

@media (min-width: 720px) {
  .page { padding: 4.5rem 2rem 5rem; }
  .scope { height: 280px; }
}