:root {
  --color-ink: #37352f;
  --color-paper: #f7f6f3;
  --color-hover-grey: #efedea;
  --color-hairline: #e9e7e4;
  --color-link-blue: #2eaadc;
  --color-marker-red: #eb5757;
  --font-sans: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", sans-serif;
  --text-display: 32px;
  --leading-display: 1.2;
  --tracking-display: -0.01em;
  --text-heading: 24px;
  --leading-heading: 1.3;
  --text-subheading: 20px;
  --leading-subheading: 1.4;
  --text-body-lg: 16px;
  --leading-body-lg: 1.6;
  --text-body: 14px;
  --leading-body: 1.6;
  --text-label: 12px;
  --leading-label: 1.4;
  --tracking-label: 0.02em;
  --font-weight-regular: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --spacing-4: 4px;
  --spacing-8: 8px;
  --spacing-12: 12px;
  --spacing-16: 16px;
  --spacing-24: 24px;
  --spacing-32: 32px;
  --spacing-48: 48px;
  --spacing-64: 64px;
  --spacing-96: 96px;
  --page-max-width: 708px;
  --section-gap: 48px;
  --card-padding: 16px;
  --element-gap: 8px;
  --radius-cards: 4px;
  --radius-buttons: 4px;
  --radius-inputs: 4px;
  --radius-pills: 999px;
  --surface-paper: #f7f6f3;
  --surface-white-page: #ffffff;
  --surface-hover-grey: #efedea;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--color-paper);
  color: var(--color-ink);
  font-family: var(--font-sans);
  font-size: var(--text-body);
  line-height: var(--leading-body);
  font-weight: var(--font-weight-regular);
}

a { color: var(--color-link-blue); text-decoration: none; }
a:hover { text-decoration: underline; }

audio { width: 100%; height: 40px; }

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--spacing-16);
  padding: var(--spacing-8) var(--spacing-24);
  border-bottom: 1px solid var(--color-hairline);
  background: var(--color-paper);
  position: sticky;
  top: 0;
  z-index: 10;
}

.wordmark {
  color: var(--color-ink);
  font-size: var(--text-body-lg);
  font-weight: var(--font-weight-semibold);
  letter-spacing: var(--tracking-display);
}
.wordmark:hover { text-decoration: none; }

.topnav { display: flex; gap: var(--spacing-4); flex-wrap: wrap; }

.shell {
  display: flex;
  gap: var(--spacing-48);
  align-items: flex-start;
  padding: var(--spacing-32) var(--spacing-24) var(--spacing-96);
  max-width: 1100px;
  margin: 0 auto;
}

.sidebar {
  width: 240px;
  flex: 0 0 240px;
  position: sticky;
  top: 64px;
}

.column {
  width: 100%;
  max-width: var(--page-max-width);
  min-width: 0;
}

.label {
  font-size: var(--text-label);
  line-height: var(--leading-label);
  letter-spacing: var(--tracking-label);
  font-weight: var(--font-weight-medium);
  text-transform: uppercase;
  opacity: 0.6;
  margin: 0 0 var(--spacing-8);
}

.sidebar-label { margin-top: var(--spacing-32); }

.steps { list-style: none; margin: 0; padding: 0; }
.plain-list { list-style: none; margin: 0; padding: 0; }
.plain-list li { padding: var(--spacing-4) var(--spacing-8); opacity: 0.75; }

.step-num {
  display: inline-block;
  min-width: 18px;
  font-weight: var(--font-weight-semibold);
}

.block-row {
  display: flex;
  align-items: baseline;
  gap: var(--spacing-8);
  padding: var(--spacing-4) var(--spacing-8);
  border-radius: var(--radius-cards);
  background: transparent;
  transition: background-color 150ms ease;
}
.block-row:hover { background: var(--color-hover-grey); }

.handle {
  width: 16px;
  flex: 0 0 16px;
  text-align: center;
  opacity: 0;
  transition: opacity 150ms ease;
  user-select: none;
}
.block-row:hover .handle, .block-row:focus-within .handle { opacity: 0.45; }

.display {
  font-size: var(--text-display);
  line-height: var(--leading-display);
  letter-spacing: var(--tracking-display);
  font-weight: var(--font-weight-semibold);
  margin: 0 0 var(--spacing-16);
}

.heading {
  font-size: var(--text-heading);
  line-height: var(--leading-heading);
  font-weight: var(--font-weight-semibold);
  margin: 0 0 var(--spacing-16);
  padding-bottom: var(--spacing-8);
  border-bottom: 1px solid var(--color-hairline);
}

.body-lg { font-size: var(--text-body-lg); line-height: var(--leading-body-lg); margin: 0 0 var(--spacing-24); max-width: 80ch; }
.body-text { margin: 0 0 var(--spacing-16); }
.muted { opacity: 0.65; }
.hint { font-size: var(--text-label); line-height: var(--leading-label); opacity: 0.6; margin: var(--spacing-8) 0 0; }

.section { margin-top: var(--section-gap); }
.intro { margin-top: var(--spacing-8); }

.callout {
  display: flex;
  gap: var(--spacing-8);
  background: var(--color-hover-grey);
  border-radius: var(--radius-cards);
  padding: var(--spacing-12) var(--spacing-16);
}
.callout p { margin: 0; }
.callout-mark { flex: 0 0 8px; }

.ghost-btn {
  appearance: none;
  background: transparent;
  border: none;
  border-radius: var(--radius-buttons);
  color: var(--color-ink);
  font-family: inherit;
  font-size: 13px;
  font-weight: var(--font-weight-medium);
  padding: var(--spacing-4) var(--spacing-8);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: background-color 150ms ease;
  text-decoration: none;
}
.ghost-btn:hover { background: var(--color-hover-grey); text-decoration: none; }
.ghost-btn:active { background: #e3e1db; }

.primary-btn {
  appearance: none;
  background: var(--color-ink);
  border: none;
  border-radius: var(--radius-buttons);
  color: var(--color-paper);
  font-family: inherit;
  font-size: var(--text-body);
  font-weight: var(--font-weight-medium);
  padding: var(--spacing-8) var(--spacing-16);
  cursor: pointer;
  transition: background-color 150ms ease;
  display: inline-block;
  text-decoration: none;
}
.primary-btn:hover { background: #4a473f; text-decoration: none; }
.primary-btn:disabled { opacity: 0.35; cursor: not-allowed; }

.dropzone {
  background: var(--surface-white-page);
  border: 1px solid var(--color-hairline);
  border-radius: var(--radius-cards);
  padding: var(--spacing-32) var(--spacing-16);
  text-align: left;
  cursor: pointer;
  transition: background-color 150ms ease;
}
.dropzone:hover, .dropzone.dragging { background: var(--color-hover-grey); }
.drop-title { font-size: var(--text-body-lg); font-weight: var(--font-weight-medium); margin: 0 0 var(--spacing-4); }
.drop-sub { margin: 0; opacity: 0.6; font-size: var(--text-label); line-height: var(--leading-label); }

.row-actions { margin-top: var(--spacing-12); display: flex; gap: var(--spacing-8); flex-wrap: wrap; }

.file-row { margin-top: var(--spacing-12); background: var(--surface-white-page); border: 1px solid var(--color-hairline); }
.file-name { font-weight: var(--font-weight-medium); word-break: break-all; }

.pill {
  border: 1px solid var(--color-hairline);
  border-radius: var(--radius-pills);
  padding: 0 var(--spacing-8);
  font-size: var(--text-label);
  line-height: 20px;
  white-space: nowrap;
}

.error-box {
  margin-top: var(--spacing-12);
  background: var(--color-hover-grey);
  border-left: 2px solid var(--color-marker-red);
  border-radius: var(--radius-cards);
  padding: var(--spacing-12) var(--spacing-16);
  color: var(--color-ink);
}
.error-box strong { color: var(--color-marker-red); }

.preview-label { margin-top: var(--spacing-16); }

.preset-list { display: flex; flex-direction: column; gap: var(--spacing-4); margin-bottom: var(--spacing-24); }

.preset-row {
  appearance: none;
  text-align: left;
  font-family: inherit;
  font-size: var(--text-body);
  line-height: var(--leading-body);
  color: var(--color-ink);
  background: transparent;
  border: 1px solid transparent;
  border-radius: var(--radius-cards);
  padding: var(--spacing-12) var(--spacing-16);
  cursor: pointer;
  transition: background-color 150ms ease;
  width: 100%;
}
.preset-row:hover { background: var(--color-hover-grey); }
.preset-row.selected { background: var(--surface-white-page); border-color: var(--color-hairline); }
.preset-head { display: flex; align-items: center; gap: var(--spacing-8); flex-wrap: wrap; margin-bottom: var(--spacing-4); }
.preset-name { font-weight: var(--font-weight-semibold); font-size: var(--text-body-lg); }
.preset-desc { opacity: 0.7; margin: 0; }

.controls { display: grid; grid-template-columns: 1fr 1fr; gap: var(--spacing-24); margin-bottom: var(--spacing-24); }
.seed-row { display: flex; gap: var(--spacing-8); align-items: center; }

.inline-input {
  background: transparent;
  border: none;
  border-bottom: 1px solid transparent;
  border-radius: 0;
  padding: var(--spacing-4) var(--spacing-8);
  font-family: inherit;
  font-size: var(--text-body);
  color: var(--color-ink);
  width: 100%;
  min-width: 0;
}
.inline-input::placeholder { color: var(--color-ink); opacity: 0.6; }
.inline-input:focus { outline: none; border-bottom: 1px solid var(--color-hairline); }

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

.config { border-top: 1px solid var(--color-hairline); }
.config-row {
  display: flex;
  justify-content: space-between;
  gap: var(--spacing-16);
  padding: var(--spacing-8);
  border-bottom: 1px solid var(--color-hairline);
}
.config-key { opacity: 0.6; }
.config-val { font-weight: var(--font-weight-medium); text-align: right; }

.progress { margin-top: var(--spacing-16); }
.progress-track { height: 4px; background: var(--color-hover-grey); border-radius: var(--radius-pills); overflow: hidden; }
.progress-fill { height: 100%; width: 0%; background: var(--color-ink); transition: width 150ms ease; }

.stage-list { list-style: none; margin: var(--spacing-16) 0 0; padding: 0; }
.stage-status { margin-left: auto; font-size: var(--text-label); letter-spacing: var(--tracking-label); text-transform: uppercase; opacity: 0.55; white-space: nowrap; }
.stage-row.running .stage-status { opacity: 1; }
.stage-row.done .stage-status { opacity: 0.85; }
.stage-row.failed .stage-status { color: var(--color-marker-red); opacity: 1; }

.stats {
  margin-top: var(--spacing-24);
  background: var(--surface-white-page);
  border: 1px solid var(--color-hairline);
  border-radius: var(--radius-cards);
  padding: var(--card-padding);
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(110px, 1fr));
  gap: var(--spacing-16);
}
.stat-value { font-size: var(--text-subheading); line-height: var(--leading-subheading); font-weight: var(--font-weight-semibold); display: block; }
.stat-key { font-size: var(--text-label); opacity: 0.6; }

.mapping { display: flex; flex-direction: column; }
.map-arrow { opacity: 0.45; }
.pipeline-note { margin-top: var(--spacing-16); }

.download-btn[aria-disabled="true"] { opacity: 0.35; pointer-events: none; }

.footer {
  margin-top: var(--spacing-64);
  padding-top: var(--spacing-16);
  border-top: 1px solid var(--color-hairline);
  display: flex;
  justify-content: space-between;
  gap: var(--spacing-16);
  flex-wrap: wrap;
  font-size: var(--text-label);
  opacity: 0.65;
}

:focus-visible { outline: 1px solid var(--color-ink); outline-offset: 2px; }

@media (max-width: 900px) {
  .shell { flex-direction: column; gap: var(--spacing-24); padding: var(--spacing-24) var(--spacing-16) var(--spacing-64); }
  .sidebar { position: static; width: 100%; flex: none; }
  .steps { display: grid; grid-template-columns: 1fr 1fr; }
  .controls { grid-template-columns: 1fr; }
  .topbar { padding: var(--spacing-8) var(--spacing-16); }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { transition: none; }
}