:root {
  --ink-blue: #071b34;
  --blueprint-bg: #0c2b4e;
  --grid-line: rgba(133, 196, 255, 0.16);
  --grid-line-strong: rgba(133, 196, 255, 0.32);
  --linework: #7fc1ff;
  --paper: #f3f1e9;
  --paper-dark: #e7e3d6;
  --ink: #10141a;
  --ink-soft: #4b5561;
  --stamp: #ff6b45;
  --stamp-dark: #d8502d;
  --ok: #4fd1a5;
  --error: #e5484d;
}
* {
  box-sizing: border-box;
}
html,
body {
  margin: 0;
  padding: 0;
}
body {
  background: var(--ink-blue);
  color: var(--paper);
  font-family: 'IBM Plex Sans', sans-serif;
  min-height: 100vh;
  min-height: 100dvh;
  -webkit-tap-highlight-color: transparent;
}
::selection {
  background: var(--stamp);
  color: var(--paper);
}
@media (prefers-reduced-motion: reduce) {
  * {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
  }
}

/* ---------- layout ---------- */
.app {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  min-height: 100dvh;
}

header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 16px max(28px, env(safe-area-inset-left)) 16px
    max(28px, env(safe-area-inset-right));
  border-bottom: 1px solid var(--grid-line-strong);
  background: linear-gradient(var(--ink-blue), var(--ink-blue));
  position: relative;
  z-index: 5;
}
.brand {
  display: flex;
  align-items: baseline;
  gap: 10px;
  min-width: 0;
}
.brand .mark {
  font-family: 'IBM Plex Mono', monospace;
  font-weight: 700;
  font-size: 20px;
  letter-spacing: 0.08em;
  color: var(--paper);
  white-space: nowrap;
}
.brand .mark span {
  color: var(--linework);
}
.brand .tagline {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11px;
  color: #9fc3e8;
  letter-spacing: 0.02em;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.stamp-badge {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 10px;
  letter-spacing: 0.08em;
  color: var(--stamp);
  border: 1px solid var(--stamp);
  padding: 3px 8px;
  border-radius: 2px;
  transform: rotate(-2deg);
  text-transform: uppercase;
  white-space: nowrap;
  flex-shrink: 0;
}
@media (max-width: 460px) {
  header {
    padding: 14px 16px;
  }
  .brand .tagline {
    display: none;
  }
}

main {
  flex: 1;
  display: flex;
  gap: 0;
  min-height: 0;
}
@media (max-width: 880px) {
  main {
    flex-direction: column;
  }
}

/* ---------- controls (paper panel) ---------- */
.controls {
  width: 360px;
  flex-shrink: 0;
  background: var(--paper);
  color: var(--ink);
  padding: 22px 22px 22px;
  overflow-y: auto;
  border-right: 1px solid #00000022;
  display: flex;
  flex-direction: column;
}
@media (max-width: 880px) {
  .controls {
    width: 100%;
    border-right: none;
    border-bottom: 1px solid #00000022;
    max-height: none;
  }
}
@media (max-width: 460px) {
  .controls {
    padding: 16px 16px 16px;
  }
}

.field-group {
  margin-bottom: 24px;
}
.field-group + .field-group {
  padding-top: 20px;
  border-top: 1px dashed #c9c4b4;
}
.field-label {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 10.5px;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--ink-soft);
  display: flex;
  align-items: center;
  gap: 6px;
  margin-bottom: 10px;
}
.field-label .idx {
  color: var(--stamp-dark);
}
.field-sub {
  font-size: 11.5px;
  color: var(--ink-soft);
  margin: -4px 0 10px;
  line-height: 1.5;
}

/* mode toggle reuses segmented look but 2-up */
.mode-toggle {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6px;
}

/* dropzone */
.dropzone-pair {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}
@media (max-width: 420px) {
  .dropzone-pair {
    grid-template-columns: 1fr;
  }
}
.dz-caption {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 10px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--ink-soft);
  margin-bottom: 6px;
}
.dropzone {
  border: 1.5px dashed #b9b2a0;
  border-radius: 6px;
  padding: 22px 14px;
  text-align: center;
  cursor: pointer;
  transition:
    border-color 0.15s ease,
    background 0.15s ease;
  background: var(--paper-dark);
}
.dropzone:hover,
.dropzone.drag {
  border-color: var(--stamp);
  background: #efe2d9;
}
.dropzone svg {
  margin-bottom: 8px;
  opacity: 0.6;
}
.dropzone .dz-title {
  font-weight: 600;
  font-size: 13.5px;
}
.dropzone .dz-sub {
  font-size: 11.5px;
  color: var(--ink-soft);
  margin-top: 4px;
}
.dropzone.has-image {
  padding: 10px;
}
.dropzone.has-image img {
  max-width: 100%;
  max-height: 90px;
  border-radius: 4px;
  display: block;
  margin: 0 auto;
}
.dropzone .swap-label {
  font-size: 11px;
  color: var(--ink-soft);
  margin-top: 6px;
}
input[type='file'] {
  display: none;
}

/* divider row for "or capture from a URL" */
.divider-row {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 16px 0 12px;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 10.5px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--ink-soft);
}
.divider-row::before,
.divider-row::after {
  content: '';
  flex: 1;
  height: 1px;
  background: #c9c4b4;
}

.url-capture-row {
  display: flex;
  gap: 8px;
}
.url-capture-row .text-input {
  flex: 1;
  min-width: 0;
}

.btn-secondary {
  font-family: 'IBM Plex Mono', monospace;
  font-weight: 600;
  font-size: 12px;
  letter-spacing: 0.02em;
  padding: 9px 14px;
  background: var(--ink);
  color: var(--paper);
  border: 1px solid var(--ink);
  border-radius: 5px;
  cursor: pointer;
  white-space: nowrap;
  flex-shrink: 0;
  min-height: 38px;
}
.btn-secondary:hover {
  background: #262c36;
}
.btn-secondary:disabled {
  background: #c9c4b4;
  border-color: #c9c4b4;
  cursor: not-allowed;
}

details.advanced-details {
  margin-top: 10px;
}
details.advanced-details summary {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11px;
  color: var(--ink-soft);
  cursor: pointer;
  user-select: none;
}
details.advanced-details summary:hover {
  color: var(--ink);
}
.advanced-body {
  margin-top: 10px;
}
.advanced-body p {
  font-size: 11.5px;
  color: var(--ink-soft);
  line-height: 1.5;
  margin: 0 0 8px;
}
.advanced-body a {
  color: var(--stamp-dark);
}

.capture-status {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11.5px;
  margin-top: 10px;
  line-height: 1.5;
  min-height: 0;
}
.capture-status.error {
  color: var(--error);
}
.capture-status.success {
  color: #2e9e7c;
}
.capture-status.loading {
  color: var(--ink-soft);
}
.capture-status:empty {
  display: none;
}

/* segmented control */
.segmented {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 6px;
}
.segmented.cols-3 {
  grid-template-columns: repeat(3, 1fr);
}
.seg-btn {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 10px;
  letter-spacing: 0.02em;
  padding: 9px 4px;
  background: var(--paper-dark);
  border: 1px solid #c9c4b4;
  border-radius: 5px;
  cursor: pointer;
  color: var(--ink);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 5px;
  transition: all 0.12s ease;
  min-height: 44px;
}
.seg-btn svg {
  width: 20px;
  height: 20px;
}
.seg-btn:hover {
  border-color: var(--ink);
}
.seg-btn.active {
  background: var(--ink);
  color: var(--paper);
  border-color: var(--ink);
}

.text-input {
  width: 100%;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 14px;
  padding: 9px 10px;
  border: 1px solid #c9c4b4;
  border-radius: 5px;
  background: #fff;
  color: var(--ink);
}
.text-input:focus,
.seg-btn:focus-visible,
.swatch:focus-visible,
button:focus-visible,
.dropzone:focus-visible {
  outline: 2px solid var(--stamp);
  outline-offset: 1px;
}

.toggle-row {
  display: flex;
  gap: 6px;
}
.toggle-row .seg-btn {
  flex: 1;
}

.swatch-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.swatch {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  border: 2px solid rgba(0, 0, 0, 0.12);
  cursor: pointer;
  position: relative;
  flex-shrink: 0;
}
.swatch.active::after {
  content: '';
  position: absolute;
  inset: -5px;
  border: 2px solid var(--stamp);
  border-radius: 50%;
}
.swatch.transparent {
  background-image:
    linear-gradient(45deg, #ccc 25%, transparent 25%),
    linear-gradient(-45deg, #ccc 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, #ccc 75%),
    linear-gradient(-45deg, transparent 75%, #ccc 75%);
  background-size: 8px 8px;
  background-position:
    0 0,
    0 4px,
    4px -4px,
    -4px 0;
  background-color: #fff;
}
.swatch.custom-color {
  display: flex;
  align-items: center;
  justify-content: center;
  background: #fff;
  overflow: hidden;
}
.swatch.custom-color input {
  width: 150%;
  height: 150%;
  border: none;
  cursor: pointer;
  padding: 0;
}

.slider-row {
  display: flex;
  align-items: center;
  gap: 10px;
}
.slider-row input[type='range'] {
  flex: 1;
  accent-color: var(--stamp);
  min-height: 24px;
}
.slider-val {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11.5px;
  width: 38px;
  text-align: right;
  color: var(--ink-soft);
  flex-shrink: 0;
}

.export-block {
  margin-top: 6px;
}
.btn-primary {
  width: 100%;
  background: var(--stamp);
  color: #fff;
  border: none;
  font-family: 'IBM Plex Mono', monospace;
  font-weight: 600;
  font-size: 13px;
  letter-spacing: 0.03em;
  padding: 13px;
  border-radius: 6px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  transition: background 0.12s ease;
  min-height: 46px;
}
.btn-primary:hover {
  background: var(--stamp-dark);
}
.btn-primary:disabled {
  background: #c9c4b4;
  cursor: not-allowed;
}
.export-scale {
  display: flex;
  gap: 6px;
  margin-top: 8px;
}
.export-scale .seg-btn {
  flex: 1;
  padding: 7px 4px;
  min-height: 38px;
}
.export-note {
  font-size: 11px;
  color: var(--ink-soft);
  margin-top: 8px;
  line-height: 1.5;
}
.export-note.error {
  color: var(--error);
}

/* sticky export on small / short viewports so it's always reachable */
@media (max-width: 880px) {
  .export-block {
    position: sticky;
    bottom: 0;
    background: var(--paper);
    margin: 20px -22px -22px;
    padding: 14px 22px calc(14px + env(safe-area-inset-bottom));
    border-top: 1px solid #00000022;
  }
}
@media (max-width: 460px) {
  .export-block {
    margin: 20px -16px -16px;
    padding: 14px 16px calc(14px + env(safe-area-inset-bottom));
  }
}

/* ---------- canvas stage (blueprint) ---------- */
.stage {
  flex: 1;
  position: relative;
  overflow: auto;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 40px;
  background-image:
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px),
    linear-gradient(var(--grid-line-strong) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line-strong) 1px, transparent 1px);
  background-size:
    16px 16px,
    16px 16px,
    80px 80px,
    80px 80px;
  background-color: var(--blueprint-bg);
}
@media (max-width: 880px) {
  .stage {
    padding: 28px 16px;
    min-height: 280px;
  }
}
.stage-inner {
  position: relative;
  max-width: 100%;
}
.dim-label {
  position: absolute;
  font-family: 'IBM Plex Mono', monospace;
  font-size: 11px;
  color: var(--linework);
  letter-spacing: 0.03em;
  white-space: nowrap;
}
.dim-label.top {
  top: -26px;
  left: 50%;
  transform: translateX(-50%);
}
.corner {
  position: absolute;
  width: 18px;
  height: 18px;
  border-color: var(--linework);
  border-style: solid;
  opacity: 0.85;
}
.corner.tl {
  top: -10px;
  left: -10px;
  border-width: 2px 0 0 2px;
}
.corner.tr {
  top: -10px;
  right: -10px;
  border-width: 2px 2px 0 0;
}
.corner.bl {
  bottom: -10px;
  left: -10px;
  border-width: 0 0 2px 2px;
}
.corner.br {
  bottom: -10px;
  right: -10px;
  border-width: 0 2px 2px 0;
}

#outputCanvas {
  display: block;
  max-width: 100%;
  height: auto;
}

.empty-note {
  font-family: 'IBM Plex Mono', monospace;
  color: #9fc3e8;
  font-size: 13px;
  text-align: center;
  max-width: 300px;
  line-height: 1.6;
}
.empty-note b {
  color: var(--paper);
}

.footnote {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 10.5px;
  color: #7fa0c4;
  text-align: center;
  padding: 10px max(10px, env(safe-area-inset-left));
  border-top: 1px solid var(--grid-line-strong);
}

/* visibility toggles driven by data-mode on .app */
.app[data-mode='single'] .pair-only {
  display: none !important;
}
.app[data-mode='pair'] .single-only {
  display: none !important;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}