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

/* ---- Top-level layout ---- */
#app {
  display: grid;
  grid-template-columns: 1fr 220px;
  grid-template-rows: auto 1fr auto;
  grid-template-areas:
    "pattern  sidebar"
    "middle   sidebar"
    "explain  sidebar";
  height: 100vh;
  overflow: hidden;
}

/* ---- Pattern section ---- */
#pattern-section {
  grid-area: pattern;
  padding: 6px 8px;
  display: flex;
  flex-direction: column;
  gap: 4px;
  border-bottom: 1px solid var(--sz-color-button-shadow);
  background: var(--sz-color-button-face);
}

.pattern-row {
  display: flex;
  align-items: center;
  gap: 4px;
}

/* Intentional regex delimiter color */
.pattern-delim {
  font-family: 'Lucida Console', Consolas, monospace;
  font-size: 14px;
  font-weight: bold;
  color: #cc3333;
}

#regex-input {
  flex: 1;
  font-family: 'Lucida Console', Consolas, monospace;
  font-size: 12px;
  padding: 2px 4px;
  border: 2px inset;
  border-color: var(--sz-color-button-shadow) var(--sz-color-button-highlight) var(--sz-color-button-highlight) var(--sz-color-button-shadow);
  background: var(--sz-color-window);
  color: var(--sz-color-window-text);
}

.flags-row {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

.flags-row label {
  display: flex;
  align-items: center;
  gap: 2px;
  cursor: default;
  font-size: 10px;
}

.flags-row input[type="checkbox"] { margin: 0; }

.subst-row {
  display: flex;
  align-items: center;
  gap: 4px;
}

.subst-row label {
  font-size: 10px;
  font-weight: bold;
  white-space: nowrap;
}

#subst-input {
  flex: 1;
  font-family: 'Lucida Console', Consolas, monospace;
  font-size: 12px;
  padding: 2px 4px;
  border: 2px inset;
  border-color: var(--sz-color-button-shadow) var(--sz-color-button-highlight) var(--sz-color-button-highlight) var(--sz-color-button-shadow);
  background: var(--sz-color-window);
  color: var(--sz-color-window-text);
}

.error-bar {
  color: #cc0000;
  font-size: 10px;
  min-height: 12px;
  font-family: 'Lucida Console', Consolas, monospace;
}

/* ---- Middle section (test + matches + table) ---- */
#middle-section {
  grid-area: middle;
  display: grid;
  grid-template-columns: 1fr 4px 200px;
  grid-template-rows: 1fr;
  gap: 0;
  overflow: hidden;
  min-height: 0;
}

/* Splitters */
#splitter-h {
  grid-column: 2;
  grid-row: 1;
  cursor: col-resize;
  background: var(--sz-color-button-face);
  border-left: 1px solid var(--sz-color-button-shadow);
  border-right: 1px solid var(--sz-color-button-shadow);
}

#splitter-v {
  grid-column: 1 / -1;
  grid-row: 2;
  cursor: row-resize;
  background: var(--sz-color-button-face);
  border-top: 1px solid var(--sz-color-button-shadow);
  border-bottom: 1px solid var(--sz-color-button-shadow);
  display: none;
}

#splitter-v.visible { display: block; }

/* Test string area */
#test-area {
  grid-column: 1;
  grid-row: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

#test-area-label {
  padding: 2px 8px;
  font-weight: bold;
  font-size: 10px;
  background: var(--sz-color-button-face);
  border-bottom: 1px solid var(--sz-color-button-shadow);
}

#test-wrap {
  flex: 1;
  position: relative;
  overflow: hidden;
}

#test-highlight {
  position: absolute;
  inset: 0;
  padding: 4px 4px 4px 36px;
  font-family: 'Lucida Console', Consolas, monospace;
  font-size: 12px;
  line-height: 1.5;
  white-space: pre-wrap;
  word-wrap: break-word;
  overflow-y: auto;
  color: transparent;
  background: var(--sz-color-window);
  pointer-events: none;
}

#test-input {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  padding: 4px 4px 4px 36px;
  font-family: 'Lucida Console', Consolas, monospace;
  font-size: 12px;
  line-height: 1.5;
  border: none;
  resize: none;
  background: transparent;
  color: var(--sz-color-window-text);
  caret-color: var(--sz-color-window-text);
  outline: none;
  white-space: pre-wrap;
  word-wrap: break-word;
  overflow-y: auto;
  user-select: text;
  -webkit-user-select: text;
}

#line-numbers {
  position: absolute;
  top: 0;
  left: 0;
  width: 32px;
  padding: 4px 4px 4px 2px;
  font-family: 'Lucida Console', Consolas, monospace;
  font-size: 12px;
  line-height: 1.5;
  text-align: right;
  color: var(--sz-color-gray-text);
  background: var(--sz-color-button-face);
  border-right: 1px solid var(--sz-color-button-shadow);
  overflow: hidden;
  pointer-events: none;
  white-space: pre;
}

/* Match highlights -- intentional regex match colors */
.hl-match { background: #ffff99; border-radius: 1px; }
.hl-group1 { background: #aaddff; border-radius: 1px; }
.hl-group2 { background: #ffccaa; border-radius: 1px; }
.hl-group3 { background: #ccffcc; border-radius: 1px; }
.hl-group4 { background: #ffaaff; border-radius: 1px; }
.hl-group5 { background: #aaffff; border-radius: 1px; }

/* Match details panel */
#match-panel {
  grid-column: 3;
  grid-row: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

#match-panel-header {
  padding: 2px 6px;
  font-weight: bold;
  font-size: 10px;
  background: var(--sz-color-button-face);
  border-bottom: 1px solid var(--sz-color-button-shadow);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

#match-count {
  font-weight: normal;
  color: var(--sz-color-gray-text);
}

#match-list {
  flex: 1;
  overflow-y: auto;
  padding: 4px;
  background: var(--sz-color-window);
  font-size: 10px;
}

.match-item {
  margin-bottom: 6px;
  padding: 3px 4px;
  border: 1px solid var(--sz-color-button-shadow);
  background: var(--sz-color-button-face);
}

.match-item-header {
  font-weight: bold;
  margin-bottom: 2px;
  color: var(--sz-color-button-text);
}

/* Intentional match highlight color */
.match-item-text {
  font-family: 'Lucida Console', Consolas, monospace;
  background: #ffff99;
  padding: 0 2px;
  word-break: break-all;
}

.match-item-pos {
  color: var(--sz-color-gray-text);
  font-size: 9px;
}

.match-group {
  margin-top: 2px;
  padding-left: 8px;
  font-size: 9px;
}

.match-group-label {
  font-weight: bold;
  color: var(--sz-color-gray-text);
}

.match-group-value {
  font-family: 'Lucida Console', Consolas, monospace;
  padding: 0 2px;
  word-break: break-all;
}

/* Replace result */
#replace-section {
  border-top: 1px solid var(--sz-color-button-shadow);
  padding: 4px;
  background: var(--sz-color-window);
  max-height: 60px;
  overflow-y: auto;
  display: none;
}

#replace-section.visible { display: block; }

#replace-label {
  font-weight: bold;
  font-size: 9px;
  color: var(--sz-color-gray-text);
  margin-bottom: 2px;
}

#replace-result {
  font-family: 'Lucida Console', Consolas, monospace;
  font-size: 11px;
  white-space: pre-wrap;
  word-break: break-all;
  user-select: text;
  -webkit-user-select: text;
}

/* Match table */
#match-table-section {
  grid-column: 1 / -1;
  grid-row: 3;
  display: none;
  flex-direction: column;
  overflow: hidden;
}

#match-table-section.visible { display: flex; }

#match-table-header {
  padding: 2px 6px;
  font-weight: bold;
  font-size: 10px;
  background: var(--sz-color-button-face);
  border-bottom: 1px solid var(--sz-color-button-shadow);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.match-table-export {
  display: flex;
  gap: 2px;
}

.match-table-export .copy-btn {
  display: inline;
  width: auto;
  padding: 0 4px;
}

.export-btn::before {
  content: '';
  display: inline-block;
  width: 9px;
  height: 9px;
  margin-right: 2px;
  vertical-align: text-bottom;
  background: currentColor;
  -webkit-mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16'%3E%3Cpath fill-rule='evenodd' d='M1 0h11l3 3v12H1V0zm3 1v4h7V1zm0 8v6h8V9z'/%3E%3C/svg%3E") center / contain no-repeat;
  mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16'%3E%3Cpath fill-rule='evenodd' d='M1 0h11l3 3v12H1V0zm3 1v4h7V1zm0 8v6h8V9z'/%3E%3C/svg%3E") center / contain no-repeat;
}

#match-table-wrap {
  flex: 1;
  overflow: auto;
  background: var(--sz-color-window);
}

#match-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 9px;
  font-family: 'Lucida Console', Consolas, monospace;
}

#match-table th {
  position: sticky;
  top: 0;
  background: var(--sz-color-button-face);
  border: 1px solid var(--sz-color-button-shadow);
  padding: 1px 3px;
  font-size: 9px;
  text-align: left;
  white-space: nowrap;
}

#match-table td {
  border: 1px solid var(--sz-color-button-shadow);
  padding: 1px 3px;
  word-break: break-all;
}

/* ---- Explanation section ---- */
#explain-section {
  grid-area: explain;
  border-top: 1px solid var(--sz-color-button-shadow);
  max-height: 100px;
  overflow-y: auto;
  padding: 4px 8px;
  background: var(--sz-color-window);
  font-size: 10px;
  line-height: 1.4;
}

#explain-section:empty::before {
  content: 'Enter a regex pattern above to see an explanation.';
  color: var(--sz-color-gray-text);
  font-style: italic;
}

.explain-token {
  display: inline;
}

/* Intentional regex token styling */
.explain-token code {
  font-family: 'Lucida Console', Consolas, monospace;
  background: var(--sz-color-button-face);
  padding: 0 2px;
  border: 1px solid var(--sz-color-button-shadow);
  font-size: 10px;
  color: #cc3333;
}

.explain-token .desc {
  color: var(--sz-color-window-text);
}

.explain-sep::before {
  content: ' \2192 ';
  color: var(--sz-color-gray-text);
}

/* ---- Sidebar ---- */
#sidebar {
  grid-area: sidebar;
  display: flex;
  flex-direction: column;
  border-left: 1px solid var(--sz-color-button-shadow);
  background: var(--sz-color-button-face);
  overflow-y: auto;
  overflow-x: hidden;
}

.sidebar-group {
  border-bottom: 1px solid var(--sz-color-button-shadow);
}

.sidebar-group-header {
  padding: 3px 6px;
  font-weight: bold;
  font-size: 10px;
  cursor: default;
  background: linear-gradient(to bottom, var(--sz-color-button-highlight), var(--sz-color-button-face));
  border-bottom: 1px solid var(--sz-color-button-shadow);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.sidebar-group-header .toggle {
  font-size: 9px;
  color: var(--sz-color-gray-text);
}

.sidebar-group-body {
  padding: 2px 6px 4px;
  font-size: 9px;
  display: none;
  background: var(--sz-color-window);
}

.sidebar-group.open .sidebar-group-body { display: block; }
.sidebar-group.open .toggle::after { content: '\25B2'; }
.sidebar-group:not(.open) .toggle::after { content: '\25BC'; }

.ref-row {
  display: flex;
  justify-content: space-between;
  padding: 1px 0;
  gap: 4px;
}

/* Intentional regex reference color */
.ref-row code {
  font-family: 'Lucida Console', Consolas, monospace;
  color: #cc3333;
  white-space: nowrap;
  font-size: 9px;
}

.ref-row span {
  color: var(--sz-color-window-text);
  text-align: right;
  flex: 1;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* Common patterns */
.pattern-btn {
  display: block;
  width: 100%;
  text-align: left;
  padding: 2px 4px;
  font-size: 9px;
  font-family: inherit;
  background: transparent;
  border: 1px solid transparent;
  cursor: default;
  color: var(--sz-color-button-text);
}

.pattern-btn:hover {
  background: var(--sz-color-highlight);
  color: var(--sz-color-highlight-text);
  border-color: var(--sz-color-highlight);
}

/* Copy-as section */
.copy-section {
  padding: 2px 6px 4px;
  background: var(--sz-color-window);
}

.copy-btn {
  display: block;
  width: 100%;
  text-align: left;
  padding: 2px 4px;
  font-size: 9px;
  font-family: inherit;
  background: transparent;
  border: 1px solid transparent;
  cursor: default;
  color: var(--sz-color-button-text);
}

.copy-btn:hover {
  background: var(--sz-color-highlight);
  color: var(--sz-color-highlight-text);
  border-color: var(--sz-color-highlight);
}

/* History */
.history-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1px 4px;
  border: 1px solid transparent;
  cursor: default;
  gap: 4px;
}

.history-item:hover {
  background: var(--sz-color-highlight);
  color: var(--sz-color-highlight-text);
  border-color: var(--sz-color-highlight);
}

.history-item code {
  font-family: 'Lucida Console', Consolas, monospace;
  font-size: 9px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  flex: 1;
}

.history-item .history-del {
  font-size: 8px;
  color: var(--sz-color-gray-text);
  cursor: default;
  flex-shrink: 0;
}

.history-item:hover .history-del { color: inherit; }