/* ────────────────────────────────────────────────────
   Design tokens
   ──────────────────────────────────────────────────── */
:root {
  --bg:           #F6F7FB;
  --surface:      #FFFFFF;
  --surface-2:    #F0F2F7;
  --border:       #D6DAE6;
  --border-2:     #B8BDCB;
  --text-1:       #1B1D26;
  --text-2:       #5B6275;
  --text-3:       #9299A8;
  --accent:       #3A5FBA;
  --accent-hover: #2A4A9A;
  --accent-light: #EBF0FB;
  --sidebar-w:    304px;
  --radius:       0px;        /* no border-radius — precision tool aesthetic */
}

/* ────────────────────────────────────────────────────
   Reset
   ──────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html, body { height: 100%; }

body {
  font-family: 'IBM Plex Sans', system-ui, -apple-system, sans-serif;
  font-size: 13px;
  line-height: 1.5;
  color: var(--text-1);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* hidden attribute always wins */
[hidden] { display: none !important; }

/* ────────────────────────────────────────────────────
   App shell: sidebar + preview
   ──────────────────────────────────────────────────── */
#app {
  display: grid;
  grid-template-columns: var(--sidebar-w) 1fr;
  height: 100vh;
  overflow: hidden;
}

/* ────────────────────────────────────────────────────
   Sidebar
   ──────────────────────────────────────────────────── */
#sidebar {
  display: flex;
  flex-direction: column;
  overflow: hidden;
  background: var(--surface);
  border-right: 1px solid var(--border);
}

#sidebar-header {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 14px 16px;
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
  background: var(--surface);
  position: sticky;
  top: 0;
  z-index: 1;
}

#app-name {
  font-size: 13px;
  font-weight: 600;
  color: var(--text-1);
  letter-spacing: 0.02em;
}

/* ────────────────────────────────────────────────────
   Tab strip
   ──────────────────────────────────────────────────── */
#sidebar-tabs {
  display: flex;
  flex-shrink: 0;
  border-bottom: 1px solid var(--border);
  background: var(--surface);
}

.tab-btn {
  flex: 1;
  padding: 8px 2px;
  font-family: 'IBM Plex Sans', system-ui, sans-serif;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--text-3);
  background: transparent;
  border: none;
  border-bottom: 2px solid transparent;
  cursor: pointer;
  transition: color 0.1s, border-bottom-color 0.1s;
  margin-bottom: -1px;
}

.tab-btn.active {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

.tab-btn:hover:not(.active) {
  color: var(--text-2);
}

/* ────────────────────────────────────────────────────
   Tab panels
   ──────────────────────────────────────────────────── */
.tab-panel {
  display: none;
  flex-direction: column;
  flex: 1;
  min-height: 0;
  padding: 14px 16px;
  overflow-y: auto;
  scrollbar-width: thin;
  scrollbar-color: var(--border) transparent;
}

.tab-panel.active {
  display: flex;
}

/* Sub-section label within a tab panel (e.g. "Calibration", "Presets" in Print) */
.group-label {
  font-size: 11px;
  font-weight: 600;
  color: var(--text-3);
  letter-spacing: 0.03em;
  margin-bottom: 8px;
}

/* ────────────────────────────────────────────────────
   Panels (legacy — kept for .subsection border utility)
   ──────────────────────────────────────────────────── */
.panel {
  padding: 12px 16px 14px;
  border-bottom: 1px solid var(--border);
}

.panel-title {
  font-size: 11px;
  font-weight: 600;
  color: var(--text-3);
  letter-spacing: 0.03em;
  margin-bottom: 10px;
  padding-bottom: 6px;
  border-bottom: 1px solid var(--border);
}

/* ────────────────────────────────────────────────────
   Field rows: label + input grid
   ──────────────────────────────────────────────────── */
.field {
  display: grid;
  grid-template-columns: 68px 1fr;
  gap: 8px;
  align-items: center;
  margin-bottom: 5px;
}

.field > label {
  font-size: 12px;
  color: var(--text-2);
  text-align: right;
  white-space: nowrap;
  user-select: none;
  line-height: 1.4;
}

/* input+unit composite */
.input-unit {
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: stretch;
  border: 1px solid var(--border);
  background: var(--surface);
  transition: border-color 0.1s;
}

.input-unit:focus-within {
  border-color: var(--accent);
  outline: 1px solid var(--accent);
  outline-offset: -1px;
}

.input-unit input {
  border: none;
  background: transparent;
  outline: none;
  padding: 4px 6px;
  width: 100%;
  font-family: 'IBM Plex Mono', 'Menlo', monospace;
  font-size: 12px;
  color: var(--text-1);
}

.unit {
  display: flex;
  align-items: center;
  padding: 0 7px 0 2px;
  font-size: 11px;
  color: var(--text-3);
  user-select: none;
  pointer-events: none;
}

/* standalone inputs and selects in .field */
.field > input[type="number"],
.field > select {
  width: 100%;
  padding: 4px 6px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text-1);
  font-size: 12px;
  transition: border-color 0.1s;
}

.field > input[type="number"] {
  font-family: 'IBM Plex Mono', 'Menlo', monospace;
}

.field > select {
  font-family: 'IBM Plex Sans', system-ui, sans-serif;
  appearance: none;
  -webkit-appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg width='8' height='5' viewBox='0 0 8 5' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M0 0l4 5 4-5z' fill='%239299A8'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 8px center;
  padding-right: 22px;
  cursor: pointer;
}

.field > input:focus,
.field > select:focus {
  outline: 2px solid var(--accent);
  outline-offset: -1px;
  border-color: var(--accent);
}

/* Color picker pair */
.color-pair {
  display: flex;
  gap: 6px;
  align-items: center;
}

.color-pair input[type="color"] {
  width: 36px;
  height: 26px;
  border: 1px solid var(--border);
  background: none;
  padding: 2px;
  cursor: pointer;
  transition: border-color 0.1s;
}

.color-pair input[type="color"]:hover { border-color: var(--border-2); }
.color-pair input[type="color"]:focus { outline: 2px solid var(--accent); outline-offset: -1px; }

/* ────────────────────────────────────────────────────
   Color swatches
   ──────────────────────────────────────────────────── */
.swatch-save-row {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 5px;
  margin-bottom: 6px;
}

.swatch-save-row input[type="text"] {
  font-family: 'IBM Plex Sans', system-ui, sans-serif;
  font-size: 12px;
  padding: 4px 6px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text-1);
}

.swatch-save-row input[type="text"]::placeholder { color: var(--text-3); }

.swatch-save-row input[type="text"]:focus {
  outline: 2px solid var(--accent);
  outline-offset: -1px;
  border-color: var(--accent);
}

.swatch-save-row button {
  font-family: 'IBM Plex Sans', system-ui, sans-serif;
  font-size: 12px;
  font-weight: 600;
  padding: 4px 10px;
  background: var(--accent);
  color: #ffffff;
  border: 1px solid var(--accent);
  cursor: pointer;
  white-space: nowrap;
}

.swatch-save-row button:hover { background: var(--accent-hover); border-color: var(--accent-hover); }

#swatch-list:empty::after {
  content: 'No saved palettes';
  display: block;
  font-size: 11px;
  color: var(--text-3);
  padding: 2px 0;
}

.swatch-item {
  display: flex;
  align-items: center;
  gap: 7px;
  width: 100%;
  padding: 4px 4px 4px 4px;
  margin-bottom: 3px;
  border: 1px solid var(--border);
  background: var(--surface);
  cursor: pointer;
  font-family: inherit;
  text-align: left;
  transition: border-color 0.1s;
}

.swatch-item:hover { border-color: var(--accent); }

.swatch-pair {
  display: flex;
  width: 30px;
  height: 16px;
  flex-shrink: 0;
  border: 1px solid rgba(27, 29, 38, 0.12);
}

.swatch-fg,
.swatch-accent {
  flex: 1;
}

.swatch-name {
  flex: 1;
  font-family: 'IBM Plex Mono', 'Menlo', monospace;
  font-size: 11px;
  color: var(--text-2);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  min-width: 0;
}

.swatch-delete {
  flex-shrink: 0;
  background: none;
  border: none;
  padding: 0 2px;
  font-size: 14px;
  line-height: 1;
  color: var(--text-3);
  cursor: pointer;
  transition: color 0.1s;
}

.swatch-delete:hover { color: #C0392B; }

/* ────────────────────────────────────────────────────
   Checkbox rows
   ──────────────────────────────────────────────────── */
.check-row {
  display: flex;
  align-items: center;
  gap: 7px;
  cursor: pointer;
  padding: 3px 0;
  font-size: 12px;
  color: var(--text-1);
  user-select: none;
}

.check-row input[type="checkbox"] {
  width: 13px;
  height: 13px;
  margin: 0;
  flex-shrink: 0;
  accent-color: var(--accent);
  cursor: pointer;
}

/* Pair of checkboxes side by side */
.check-pair {
  display: flex;
  gap: 18px;
  margin-bottom: 4px;
}

/* Pair of fields side by side */
.field-pair {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6px;
  margin-bottom: 5px;
}

.field-pair .field {
  grid-template-columns: auto 1fr;
  gap: 4px;
  margin-bottom: 0;
}

.field-pair .field > label { text-align: left; }

/* ────────────────────────────────────────────────────
   Rule-type subsections
   ──────────────────────────────────────────────────── */
.subsection {
  margin-top: 8px;
  padding-top: 8px;
  border-top: 1px solid var(--border);
}

.tab-panel > .subsection:first-child,
.tab-panel > section:first-child {
  border-top: none;
  padding-top: 0;
  margin-top: 0;
}

.tab-panel .unit-toggle {
  margin-bottom: 5px;
  margin-right: auto;
}

/* ────────────────────────────────────────────────────
   Export buttons
   ──────────────────────────────────────────────────── */
.export-btn {
  display: block;
  width: 100%;
  padding: 7px 12px;
  margin-bottom: 4px;
  font-family: 'IBM Plex Sans', system-ui, sans-serif;
  font-size: 12px;
  font-weight: 600;
  text-align: center;
  cursor: pointer;
  border: 1px solid var(--border-2);
  background: transparent;
  color: var(--text-2);
  transition: background 0.1s, color 0.1s, border-color 0.1s;
}

.export-btn:hover {
  background: var(--surface-2);
  color: var(--text-1);
  border-color: var(--border-2);
}

.export-btn--primary {
  background: var(--accent);
  color: #ffffff;
  border-color: var(--accent);
}

.export-btn--primary:hover {
  background: var(--accent-hover);
  color: #ffffff;
  border-color: var(--accent-hover);
}

/* ────────────────────────────────────────────────────
   Presets
   ──────────────────────────────────────────────────── */
.preset-save-row {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 5px;
  margin-bottom: 7px;
}

.preset-save-row input[type="text"] {
  font-family: 'IBM Plex Sans', system-ui, sans-serif;
  font-size: 12px;
  padding: 5px 7px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text-1);
}

.preset-save-row input[type="text"]::placeholder { color: var(--text-3); }

.preset-save-row input[type="text"]:focus {
  outline: 2px solid var(--accent);
  outline-offset: -1px;
  border-color: var(--accent);
}

.preset-save-row button {
  font-family: 'IBM Plex Sans', system-ui, sans-serif;
  font-size: 12px;
  font-weight: 600;
  padding: 5px 10px;
  background: var(--accent);
  color: #ffffff;
  border: 1px solid var(--accent);
  cursor: pointer;
  white-space: nowrap;
}

.preset-save-row button:hover { background: var(--accent-hover); border-color: var(--accent-hover); }

.preset-select {
  display: block;
  width: 100%;
  font-family: 'IBM Plex Sans', system-ui, sans-serif;
  font-size: 12px;
  padding: 5px 22px 5px 7px;
  border: 1px solid var(--border);
  background: var(--surface);
  background-image: url("data:image/svg+xml,%3Csvg width='8' height='5' viewBox='0 0 8 5' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M0 0l4 5 4-5z' fill='%239299A8'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 7px center;
  color: var(--text-1);
  margin-bottom: 6px;
  appearance: none;
  -webkit-appearance: none;
  cursor: pointer;
}

.preset-select:focus {
  outline: 2px solid var(--accent);
  outline-offset: -1px;
  border-color: var(--accent);
}

.preset-actions {
  display: flex;
  gap: 4px;
  margin-bottom: 4px;
}

.btn-ghost {
  flex: 1;
  padding: 5px 6px;
  background: transparent;
  color: var(--text-2);
  border: 1px solid var(--border);
  font-family: 'IBM Plex Sans', system-ui, sans-serif;
  font-size: 11px;
  font-weight: 400;
  text-align: center;
  cursor: pointer;
  transition: background 0.1s, color 0.1s;
}

.btn-ghost:hover {
  background: var(--surface-2);
  color: var(--text-1);
}

.btn-ghost--danger {
  color: #C0392B;
  border-color: #E8C0BC;
}

.btn-ghost--danger:hover {
  background: #FEF2F2;
  color: #991B1B;
}

/* ────────────────────────────────────────────────────
   Preview area
   ──────────────────────────────────────────────────── */
#preview-area {
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg);
  padding: 32px;
  overflow: hidden;
  min-width: 0;
}

#preview-wrap {
  display: flex;
  align-items: flex-start;
  gap: 24px;
}

.preview-side {
  display: flex;
  flex-direction: column;
  align-items: center;
  flex-shrink: 0;
}

.preview-side canvas {
  display: block;
  box-shadow:
    0 1px 2px rgba(27, 29, 38, 0.06),
    0 4px 16px rgba(27, 29, 38, 0.12),
    0 0 0 1px rgba(27, 29, 38, 0.05);
}

.preview-label {
  display: block;
  margin-top: 7px;
  font-family: 'IBM Plex Mono', 'Menlo', monospace;
  font-size: 10px;
  color: var(--text-3);
  letter-spacing: 0.04em;
  line-height: 1;
  user-select: none;
}

/* ────────────────────────────────────────────────────
   Calibration guide disclosure
   ──────────────────────────────────────────────────── */
.cal-guide {
  margin-top: 6px;
}

.cal-guide__toggle {
  display: flex;
  align-items: center;
  gap: 5px;
  cursor: pointer;
  list-style: none;
  font-size: 11px;
  font-weight: 600;
  color: var(--text-3);
  letter-spacing: 0.03em;
  user-select: none;
  padding: 2px 0;
}

.cal-guide__toggle::-webkit-details-marker { display: none; }

.cal-guide__toggle::before {
  content: '+';
  font-size: 13px;
  font-weight: 400;
  line-height: 1;
  color: var(--text-3);
  width: 10px;
  flex-shrink: 0;
}

.cal-guide[open] .cal-guide__toggle::before { content: '−'; }

.cal-guide__toggle:hover { color: var(--text-2); }

.cal-guide__body {
  padding: 8px 0 4px 15px;
  border-left: 1px solid var(--border);
  margin-left: 4px;
  margin-top: 4px;
}

.cal-guide__section {
  font-size: 11px;
  font-weight: 600;
  color: var(--text-1);
  margin-top: 8px;
  margin-bottom: 3px;
}

.cal-guide__section:first-child { margin-top: 0; }

.cal-guide__text {
  font-size: 11px;
  color: var(--text-2);
  line-height: 1.5;
  margin-bottom: 4px;
}

.cal-guide__steps {
  padding-left: 14px;
  margin: 0;
}

.cal-guide__steps li {
  font-size: 11px;
  color: var(--text-2);
  line-height: 1.5;
  margin-bottom: 3px;
}

.cal-guide__steps li b {
  font-weight: 600;
  color: var(--text-1);
}

/* ── Unit toggle ─────────────────────────────────────── */
.unit-toggle {
  display: flex;
  border: 1px solid var(--border);
}

.unit-toggle__btn {
  padding: 2px 8px;
  font-family: 'IBM Plex Sans', system-ui, sans-serif;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.03em;
  color: var(--text-3);
  background: transparent;
  border: none;
  cursor: pointer;
  line-height: 1.6;
}

.unit-toggle__btn:first-child {
  border-right: 1px solid var(--border);
}

.unit-toggle__btn.active {
  color: var(--accent);
  background: var(--accent-light);
}

.unit-toggle__btn:hover:not(.active) {
  color: var(--text-2);
  background: var(--surface-2);
}