:root {
  --paper: #f2ede2;
  --paper-dark: #e8e1d2;
  --ink: #1a1714;
  --ink-soft: #4a4138;
  --ink-mute: #8a7f70;
  --rule: #c9bfac;
  --rule-soft: #dcd2be;
  --accent: #b84a2f;
  --accent-soft: #d97a5e;
  --highlight: #e8c547;
  --sans: "IBM Plex Sans", ui-sans-serif, system-ui, sans-serif;
  --serif: "Fraunces", ui-serif, Georgia, serif;
  --mono: "JetBrains Mono", ui-monospace, Consolas, monospace;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html,
body {
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.5;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

body {
  background-image:
    radial-gradient(
      circle at 15% 20%,
      rgba(232, 197, 71, 0.04) 0%,
      transparent 40%
    ),
    radial-gradient(
      circle at 85% 70%,
      rgba(184, 74, 47, 0.04) 0%,
      transparent 50%
    );
  background-attachment: fixed;
}

a:link,
a:visited {
  color: var(--accent);
}

.grain {
  position: fixed;
  inset: 0;
  pointer-events: none;
  opacity: 0.4;
  mix-blend-mode: multiply;
  z-index: 0;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2' stitchTiles='stitch'/%3E%3CfeColorMatrix values='0 0 0 0 0.1 0 0 0 0 0.09 0 0 0 0 0.08 0 0 0 0.3 0'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.35'/%3E%3C/svg%3E");
}

.layout {
  position: relative;
  z-index: 1;
  max-width: 1400px;
  margin: 0 auto;
  padding: clamp(1.5rem, 4vw, 3rem);
}

/* ===== Masthead ===== */

.masthead {
  border-bottom: 2px solid var(--ink);
  padding-bottom: 1.5rem;
  margin-bottom: 2.5rem;
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 2rem;
  align-items: end;
}

.masthead-title {
  font-family: var(--serif);
  font-weight: 400;
  font-size: clamp(2.25rem, 6vw, 4.5rem);
  font-style: italic;
  line-height: 0.95;
  letter-spacing: -0.02em;
  font-variation-settings:
    "opsz" 144,
    "SOFT" 100;
}

.masthead-title em {
  font-style: normal;
  color: var(--accent);
  font-weight: 500;
}

.masthead-meta {
  font-family: var(--mono);
  font-size: 0.75rem;
  color: var(--ink-mute);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  text-align: right;
  line-height: 1.6;
}

.masthead-meta .line {
  display: block;
}

.masthead-meta .accent {
  color: var(--accent);
}

.masthead-tagline {
  grid-column: 1 / -1;
  font-family: var(--serif);
  font-style: italic;
  font-size: 1.125rem;
  color: var(--ink-soft);
  margin-top: 0.5rem;
  max-width: 58ch;
}

/* ===== Grid layout ===== */

.workbench {
  display: grid;
  grid-template-columns: 380px 1fr;
  gap: 2rem;
  align-items: start;
}

@media (max-width: 900px) {
  .workbench {
    grid-template-columns: 1fr;
  }
  .masthead {
    grid-template-columns: 1fr;
  }
  .masthead-meta {
    text-align: left;
  }
}

/* ===== Panels ===== */

.panel {
  background: var(--paper-dark);
  border: 1px solid var(--rule);
  padding: 1.75rem;
  position: relative;
}

.panel::before {
  content: "";
  position: absolute;
  top: -1px;
  left: -1px;
  width: 12px;
  height: 12px;
  border-top: 2px solid var(--ink);
  border-left: 2px solid var(--ink);
}

.panel::after {
  content: "";
  position: absolute;
  bottom: -1px;
  right: -1px;
  width: 12px;
  height: 12px;
  border-bottom: 2px solid var(--ink);
  border-right: 2px solid var(--ink);
}

.panel-label {
  font-family: var(--mono);
  font-size: 0.6875rem;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: var(--ink-mute);
  margin-bottom: 1.25rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.panel-label::before {
  content: "";
  display: inline-block;
  width: 8px;
  height: 8px;
  background: var(--accent);
  border-radius: 50%;
  flex-shrink: 0;
}

.panel-label .num {
  color: var(--accent);
  font-weight: 600;
}

/* ===== Input group ===== */

.input-group {
  margin-bottom: 1.5rem;
}

.input-group:last-child {
  margin-bottom: 0;
}

.input-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: 0.5rem;
  gap: 1rem;
}

.input-label {
  font-family: var(--serif);
  font-size: 1.0625rem;
  font-weight: 500;
  color: var(--ink);
  display: flex;
  align-items: baseline;
  gap: 0.5rem;
}

.input-label .symbol {
  font-family: var(--mono);
  font-size: 0.8125rem;
  color: var(--accent);
  font-weight: 600;
}

.input-label .caption {
  font-family: var(--sans);
  font-size: 0.75rem;
  color: var(--ink-mute);
  font-weight: 400;
}

.input-value {
  font-family: var(--mono);
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--ink);
  background: var(--paper);
  padding: 0.2rem 0.55rem;
  border: 1px solid var(--rule);
  min-width: 5rem;
  text-align: right;
}

.input-slider {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 2px;
  background: var(--rule);
  outline: none;
  margin: 0.5rem 0 0.25rem;
}

.input-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 18px;
  height: 18px;
  background: var(--ink);
  border-radius: 50%;
  cursor: grab;
  transition:
    transform 0.15s,
    background 0.15s;
  border: 3px solid var(--paper);
  box-shadow: 0 0 0 1px var(--ink);
}

.input-slider::-webkit-slider-thumb:hover {
  background: var(--accent);
  box-shadow: 0 0 0 1px var(--accent);
}
.input-slider::-webkit-slider-thumb:active {
  cursor: grabbing;
  transform: scale(1.15);
}

.input-slider::-moz-range-thumb {
  width: 18px;
  height: 18px;
  background: var(--ink);
  border-radius: 50%;
  cursor: grab;
  border: 3px solid var(--paper);
  box-shadow: 0 0 0 1px var(--ink);
}

.input-range {
  display: flex;
  justify-content: space-between;
  font-family: var(--mono);
  font-size: 0.6875rem;
  color: var(--ink-mute);
}

/* ===== Divider ===== */

.section-divider {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-family: var(--mono);
  font-size: 0.6875rem;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: var(--ink-mute);
  margin: 1.75rem 0 1.25rem;
}

.section-divider::before,
.section-divider::after {
  content: "";
  flex: 1;
  height: 1px;
  background: var(--rule);
}

/* ===== Results ===== */

.results-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
  margin-bottom: 1.5rem;
}

.result-cell {
  background: var(--paper);
  border: 1px solid var(--rule);
  padding: 0.875rem 1rem;
}

.result-label {
  font-family: var(--mono);
  font-size: 0.6875rem;
  color: var(--ink-mute);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: 0.2rem;
  display: flex;
  justify-content: space-between;
}

.result-label .symbol {
  color: var(--accent);
  font-weight: 600;
}

.result-value {
  font-family: var(--mono);
  font-size: 1rem;
  font-weight: 500;
  color: var(--ink);
}

/* ===== Code output ===== */

.code-output {
  background: var(--ink);
  color: var(--paper);
  padding: 1.25rem 1.5rem;
  font-family: var(--mono);
  font-size: 0.875rem;
  line-height: 1.7;
  position: relative;
  overflow-x: auto;
  margin-bottom: 1rem;
}

.code-output .prop {
  color: #e8c547;
}
.code-output .fn {
  color: #d97a5e;
}
.code-output .num {
  color: #f2ede2;
}
.code-output .unit {
  color: #b2a48c;
}
.code-output .punc {
  color: #8a7f70;
}

.copy-btn {
  position: absolute;
  top: 0.75rem;
  right: 0.75rem;
  background: transparent;
  border: 1px solid rgba(242, 237, 226, 0.25);
  color: var(--paper);
  font-family: var(--mono);
  font-size: 0.6875rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  padding: 0.375rem 0.625rem;
  cursor: pointer;
  transition: all 0.15s;
}

.copy-btn:hover {
  background: var(--accent);
  border-color: var(--accent);
}

.copy-btn.copied {
  background: var(--highlight);
  border-color: var(--highlight);
  color: var(--ink);
}

.reset-btn {
  background: transparent;
  border: 1px solid var(--rule);
  color: var(--ink-soft);
  font-family: var(--mono);
  font-size: 0.6875rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  padding: 0.625rem 1rem;
  cursor: pointer;
  transition: all 0.15s;
  width: 100%;
}

.reset-btn:hover {
  border-color: var(--ink);
  color: var(--ink);
  background: var(--paper);
}

/* ===== Right column ===== */

.right-column {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

/* ===== Graph ===== */

.graph-wrap {
  padding: 1.75rem;
}

.graph-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: 0.75rem;
}

.graph-title {
  font-family: var(--serif);
  font-size: 1.25rem;
  font-weight: 500;
  font-style: italic;
}

.graph-equation {
  font-family: var(--mono);
  font-size: 0.8125rem;
  color: var(--ink-mute);
  background: var(--paper);
  padding: 0.2rem 0.5rem;
  border: 1px solid var(--rule);
}

.graph-equation .hi {
  color: var(--accent);
  font-weight: 600;
}

.graph-svg {
  width: 100%;
  height: auto;
  display: block;
  background: var(--paper);
  border: 1px solid var(--rule);
}

.graph-legend {
  display: flex;
  gap: 1.5rem;
  margin-top: 0.75rem;
  font-family: var(--mono);
  font-size: 0.6875rem;
  color: var(--ink-mute);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  flex-wrap: wrap;
}

.legend-item {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}
.legend-swatch {
  width: 14px;
  height: 2px;
  background: var(--ink);
}
.legend-swatch.accent {
  background: var(--accent);
}
.legend-swatch.dashed {
  border-top: 2px dashed var(--ink-mute);
  background: transparent;
  height: 0;
}

/* ===== Preview ===== */

.preview-wrap {
  padding: 1.75rem;
}

.preview-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: 1.25rem;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.preview-title {
  font-family: var(--serif);
  font-size: 1.25rem;
  font-weight: 500;
  font-style: italic;
}

.preview-width-display {
  font-family: var(--mono);
  font-size: 0.8125rem;
  color: var(--ink);
  background: var(--paper);
  padding: 0.2rem 0.5rem;
  border: 1px solid var(--rule);
}

.preview-width-display .font {
  color: var(--accent);
  font-weight: 600;
}

.preview-width-control {
  margin-bottom: 1.5rem;
}

.preview-container-wrap {
  background: var(--paper);
  border: 1px solid var(--rule);
  padding: 1.5rem 1rem;
  position: relative;
  overflow: hidden;
}

.preview-ruler {
  position: relative;
  height: 24px;
  margin-bottom: 0.75rem;
}

.preview-container {
  container-type: inline-size;
  background:
    linear-gradient(135deg, rgba(26, 23, 20, 0.85), rgba(74, 65, 56, 0.9)),
    repeating-linear-gradient(
      45deg,
      transparent,
      transparent 14px,
      rgba(255, 255, 255, 0.02) 14px,
      rgba(255, 255, 255, 0.02) 28px
    );
  color: var(--paper);
  padding: clamp(1.25rem, 5cqi, 2.25rem);
  margin: 0 auto;
  transition: width 0.1s linear;
  position: relative;
  min-height: 180px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.06);
}

.preview-container::before,
.preview-container::after {
  content: "";
  position: absolute;
  top: -8px;
  bottom: -8px;
  width: 1px;
  background: var(--accent);
}

.preview-container::before {
  left: 0;
}
.preview-container::after {
  right: 0;
}

.preview-text {
  font-family: var(--serif);
  font-weight: 400;
  line-height: 1.2;
  letter-spacing: -0.01em;
  /* Font size is set via inline style from JS */
}

.preview-text .open-quote,
.preview-text .close-quote {
  color: var(--accent-soft);
}

.preview-byline {
  font-family: var(--sans);
  font-size: 0.875rem;
  color: rgba(242, 237, 226, 0.7);
  margin-top: 1rem;
  letter-spacing: 0.02em;
}

.preview-markers {
  position: relative;
  height: 1rem;
  margin-bottom: 0.5rem;
  font-family: var(--mono);
  font-size: 0.6875rem;
  color: var(--ink-mute);
}

.marker {
  position: absolute;
  transform: translateX(-50%);
  white-space: nowrap;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
}

.marker::before {
  content: "";
  width: 1px;
  height: 6px;
  background: var(--rule);
}

.marker.is-bound {
  color: var(--accent);
}
.marker.is-bound::before {
  background: var(--accent);
}

.preview-slider-wrap {
  position: relative;
  padding: 0 2px;
}

/* ===== Explanation footer ===== */

.explainer {
  margin-top: 3rem;
  border-top: 1px solid var(--rule);
  padding-top: 2rem;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.5rem;
}

.explainer-card {
  padding: 1.25rem;
  border-left: 2px solid var(--accent);
  background: var(--paper-dark);
}

.explainer-card h4 {
  font-family: var(--mono);
  font-size: 0.6875rem;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: var(--accent);
  margin-bottom: 0.5rem;
  font-weight: 600;
}

.explainer-card p {
  font-size: 0.875rem;
  color: var(--ink-soft);
  line-height: 1.55;
}

.explainer-card code {
  font-family: var(--mono);
  font-size: 0.8125rem;
  background: var(--paper);
  padding: 0.05rem 0.3rem;
  color: var(--accent);
}

/* ===== Colophon ===== */

.colophon {
  margin-top: 3rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--rule);
  font-family: var(--mono);
  font-size: 0.6875rem;
  color: var(--ink-mute);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.colophon .accent {
  color: var(--accent);
}

/* Warning when no valid line */
.warn {
  background: #f2c94c;
  color: #1a1714;
  padding: 0.5rem 0.75rem;
  font-family: var(--mono);
  font-size: 0.75rem;
  margin-top: 0.75rem;
  display: none;
}
.warn.show {
  display: block;
}