/* WillTools shared front-end look -- Panel Analysis's new 前端 today, the
   shell every future tool (Beam Analysis, Connection Analysis) and every
   results page adopts next. Reference: Eriksson Wall's own input dialogs --
   plain engineering software, dense but tidy. Light theme, one accent
   colour, system font stack, no build step, no framework. */

:root {
  --bg: #f3f4f6;
  --panel-bg: #ffffff;
  --border: #d7dae0;
  --border-strong: #b7bcc6;
  --text: #1b1e23;
  --text-muted: #6b7280;
  --text-faint: #9aa1ac;
  --accent: #2f6fed;
  --accent-dark: #1f56c9;
  --accent-contrast: #ffffff;
  --error: #d33333;
  --error-bg: #fdecec;
  --warn: #b45309;
  --warn-bg: #fff7ed;
  --row-stripe: #fafbfc;
  --row-hover: #eef2ff;
  --radius: 4px;
  --focus-ring: 0 0 0 3px rgba(47, 111, 237, 0.28);
  color-scheme: light;
}

* { box-sizing: border-box; }

html, body {
  height: 100%;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: "Segoe UI", -apple-system, BlinkMacSystemFont, "Helvetica Neue", Arial, sans-serif;
  font-size: 13px;
  line-height: 1.45;
}

button, input, select, textarea {
  font: inherit;
  color: inherit;
}

/* --------------------------------------------------------------- layout */

.app-shell {
  display: flex;
  flex-direction: column;
  height: 100vh;
}

.toolbar {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 14px;
  background: var(--panel-bg);
  border-bottom: 1px solid var(--border);
  flex: 0 0 auto;
}

.toolbar-title {
  font-size: 15px;
  font-weight: 600;
}

.pa-mark {
  font-weight: 400;
  color: var(--text-muted);
  margin-left: 6px;
}

.toolbar-spacer { flex: 1 1 auto; }

.btn {
  appearance: none;
  border: 1px solid var(--border-strong);
  background: #fff;
  color: var(--text);
  border-radius: var(--radius);
  padding: 6px 14px;
  font-size: 13px;
  cursor: pointer;
}
.btn:hover { background: #f4f5f7; }
.btn:focus-visible { outline: none; box-shadow: var(--focus-ring); }
.btn-primary {
  background: var(--accent);
  border-color: var(--accent-dark);
  color: var(--accent-contrast);
  font-weight: 600;
}
.btn-primary:hover { background: var(--accent-dark); }

.banner {
  flex: 0 0 auto;
  background: var(--error-bg);
  color: var(--error);
  border-bottom: 1px solid #f3c2c2;
  padding: 8px 14px;
  font-size: 12.5px;
}
.banner[hidden] { display: none; }
/* Two faces, never alike: amber = input still needed (the user's to fill),
   red = something broke (a bug). The bare `.banner` is red so an
   unlabelled failure is loud, never calm. */
.banner.banner--input {
  background: var(--warn-bg);
  color: var(--warn);
  border-bottom-color: #f2d9b6;
}
.banner.banner--crash {
  background: var(--error-bg);
  color: var(--error);
  border-bottom-color: #f3c2c2;
}

.spec-problems {
  flex: 0 0 auto;
  background: var(--warn-bg);
  color: var(--warn);
  border-bottom: 1px solid #f2d9b6;
  padding: 6px 14px;
  font-size: 12px;
}

.tabs {
  display: flex;
  gap: 2px;
  background: var(--panel-bg);
  border-bottom: 1px solid var(--border);
  padding: 0 10px;
  flex: 0 0 auto;
  overflow-x: auto;
}

.tab {
  appearance: none;
  border: none;
  background: transparent;
  padding: 10px 14px;
  font-size: 13px;
  color: var(--text-muted);
  cursor: pointer;
  border-bottom: 3px solid transparent;
  white-space: nowrap;
}
.tab:hover { color: var(--text); }
.tab.active {
  color: var(--text);
  font-weight: 600;
  border-bottom-color: var(--accent);
}

.pages {
  flex: 1 1 auto;
  overflow-y: auto;
  background: var(--bg);
}

.page-panel {
  display: none;
  padding: 18px 20px 60px;
  max-width: 1180px;
  margin: 0 auto;
}
.page-panel.active { display: block; }

/* -------------------------------------------------------------- headings */

h1.pa-h, h2.pa-h, h3.pa-h {
  margin: 18px 0 8px;
  font-weight: 600;
  color: var(--text);
}
h1.pa-h { font-size: 17px; border-bottom: 1px solid var(--border); padding-bottom: 6px; }
h2.pa-h { font-size: 14.5px; margin-top: 20px; }
h3.pa-h { font-size: 13.5px; color: var(--text-muted); }

hr.pa-rule {
  border: none;
  border-top: 1px solid var(--border);
  margin: 14px 0;
}

.pa-space { display: block; }

/* -------------------------------------------------------------- columns */

.pa-columns {
  display: flex;
  gap: 22px;
  align-items: flex-start;
}
.pa-col {
  flex: 1 1 0;
  min-width: 0;
}

/* ---------------------------------------------------------------- field */

.field {
  margin-bottom: 10px;
  max-width: 420px;
}
.field.full-width { max-width: none; }
.field-label-row {
  display: flex;
  align-items: baseline;
  gap: 5px;
  margin-bottom: 3px;
}
.field-label {
  font-size: 12.5px;
  color: var(--text-muted);
}
.field.required .field-label::after {
  content: " *";
  color: var(--error);
}
.field-symbol {
  font-size: 11px;
  color: var(--text-faint);
}
.field-input {
  width: 100%;
  padding: 5px 7px;
  border: 1px solid var(--border-strong);
  border-radius: var(--radius);
  background: #fff;
}
.field-input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: var(--focus-ring);
}
textarea.field-input { resize: vertical; min-height: 44px; }
.field-input.has-error {
  border-color: var(--error);
  background: var(--error-bg);
}
.field-error-msg {
  color: var(--error);
  font-size: 11px;
  margin-top: 2px;
}
.field-check-row {
  display: flex;
  align-items: center;
  gap: 6px;
}
.field-check-row .field-label { margin: 0; }

/* "not used by the solve" (docs/pa-web-spec.md, unused_by_solve) --
   collected only; muted so it can never pass for a live input */
.unused-by-solve .field-input,
tr.unused-by-solve .field-input { opacity: 0.55; }
.unused-by-solve .field-label,
tr.unused-by-solve td:first-child { color: var(--text-muted); }
.unused-tag {
  display: inline-block;
  margin-left: 6px;
  padding: 0 5px;
  border: 1px dashed var(--text-faint);
  border-radius: 3px;
  color: var(--text-muted);
  font-size: 10px;
  line-height: 15px;
  white-space: nowrap;
}

/* row-table empty state + table-level error (issue #22) */
.table-empty-state {
  color: var(--text-muted);
  font-size: 12px;
  font-style: italic;
  margin: 4px 0;
}
.editable-table-wrap.has-error table.pa-editable {
  outline: 2px solid var(--error);
  background: var(--error-bg);
}
.table-error-msg {
  color: var(--error);
  font-size: 11px;
  margin: 2px 0;
}

/* provenance */
.prov-icon {
  display: inline-block;
  width: 13px;
  height: 13px;
  line-height: 13px;
  text-align: center;
  border-radius: 50%;
  font-size: 10px;
  color: var(--accent);
  cursor: help;
  border: 1px solid var(--accent);
}

/* ------------------------------------------------------------ sentence */

.sentence { margin: 6px 0; color: var(--text); }
.sentence.emph { font-weight: 600; }

/* ------------------------------------------------------------------ kv */

table.kv-table { border-collapse: collapse; margin: 6px 0 12px; }
table.kv-table td { padding: 3px 10px 3px 0; vertical-align: top; font-size: 12.5px; }
table.kv-table td:first-child { color: var(--text-muted); white-space: nowrap; }

/* --------------------------------------------------------------- tables */

table.pa-table, table.pa-editable, table.pa-matrix, table.pa-lc {
  border-collapse: collapse;
  width: 100%;
  margin: 6px 0 14px;
  font-size: 12.5px;
}
table.pa-table th, table.pa-table td,
table.pa-editable th, table.pa-editable td,
table.pa-matrix th, table.pa-matrix td,
table.pa-lc th, table.pa-lc td {
  border: 1px solid var(--border);
  padding: 4px 6px;
  text-align: left;
  vertical-align: middle;
}
table.pa-table th, table.pa-editable th, table.pa-matrix th, table.pa-lc th {
  background: #eef1f5;
  font-weight: 600;
  color: var(--text-muted);
  white-space: nowrap;
}
table.pa-table tbody tr:nth-child(even),
table.pa-editable tbody tr:nth-child(even) {
  background: var(--row-stripe);
}
table.pa-table td input.field-input,
table.pa-editable td input.field-input,
table.pa-editable td select.field-input,
table.pa-matrix td input.field-input,
table.pa-matrix td select.field-input,
table.pa-lc td input.field-input {
  padding: 3px 5px;
  min-width: 44px;
}
table.pa-matrix td.na-cell {
  text-align: center;
  color: var(--text-faint);
}
table.pa-matrix th, table.pa-matrix td:first-child {
  white-space: normal;
}
td.row-remove { text-align: center; width: 28px; }
.row-remove-btn, .row-check {
  cursor: pointer;
  color: var(--text-muted);
  border: none;
  background: none;
  font-size: 14px;
}
.row-remove-btn:hover { color: var(--error); }
.add-row-btn {
  margin: 2px 0 14px;
}

/* -------------------------------------------------------------- legend */

.legend {
  display: flex;
  gap: 18px;
  flex-wrap: wrap;
  font-size: 12px;
  color: var(--text-muted);
  margin: 4px 0 10px;
}
.legend-group-title { font-weight: 600; margin-right: 6px; }
.legend-item { display: inline-flex; align-items: center; gap: 4px; }
.legend-glyph { font-size: 13px; }

/* ------------------------------------------------------------- drawing */

.drawing-block {
  margin: 10px 0 16px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--panel-bg);
  padding: 8px 10px;
}
.drawing-caption {
  font-size: 12px;
  color: var(--text-muted);
  margin-bottom: 6px;
}
.drawing-host { width: 100%; }
.drawing-problems {
  font-size: 11px;
  color: var(--warn);
  margin-top: 4px;
}
.drawing-problems:empty { display: none; }

/* -------------------------------------------------------------- details */

details.pa-section {
  margin: 10px 0;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--panel-bg);
}
details.pa-section > summary {
  cursor: pointer;
  padding: 8px 10px;
  font-weight: 600;
  font-size: 13px;
  list-style: none;
}
details.pa-section > summary::-webkit-details-marker { display: none; }
details.pa-section > summary::before {
  content: "▸ ";
  color: var(--text-muted);
}
details.pa-section[open] > summary::before { content: "▾ "; }
details.pa-section > .pa-section-body { padding: 4px 12px 12px; }

details.pa-notes {
  margin: 20px 0 4px;
  border: 1px dashed var(--border-strong);
  border-radius: var(--radius);
  background: #fbfbfc;
}
details.pa-notes > summary {
  cursor: pointer;
  padding: 7px 10px;
  color: var(--text-muted);
  font-size: 12.5px;
  list-style: none;
}
details.pa-notes > summary::-webkit-details-marker { display: none; }
.pa-notes-body { padding: 2px 14px 12px; font-size: 12px; color: var(--text-muted); }
.pa-notes-body h4 { margin: 8px 0 4px; font-size: 11.5px; text-transform: uppercase; letter-spacing: .03em; color: var(--text-faint); }
.pa-notes-body ul { margin: 0 0 6px; padding-left: 18px; }
.pa-notes-body li { margin-bottom: 3px; }

.unknown-block {
  background: #fff3cd;
  border: 1px solid #ffe08a;
  border-radius: var(--radius);
  padding: 6px 10px;
  font-size: 12px;
  margin: 6px 0;
}

#errors {
  position: fixed;
  left: 0; right: 0; bottom: 0;
  max-height: 30vh;
  overflow: auto;
  margin: 0;
  background: #2b0000;
  color: #ffd9d9;
  font-size: 11px;
  padding: 8px 10px;
  z-index: 999;
  white-space: pre-wrap;
}
#errors[hidden] { display: none; }