:root {
  color-scheme: dark;
  --bg: #14161a;
  --bg-alt: #1c1f26;
  --panel: #21242c;
  --border: #333844;
  --text: #e8eaed;
  --text-dim: #9aa0ab;
  --accent: #5b8cff;
  --accent-dim: #2e3f6b;
  --danger: #e0596b;
  --error: #ff8080;
  --radius: 8px;
}

* { box-sizing: border-box; }

[hidden] { display: none !important; }

html, body {
  margin: 0;
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: "Segoe UI", system-ui, -apple-system, sans-serif;
  font-size: 14px;
}

button, input, select {
  font-family: inherit;
  font-size: 14px;
  color: var(--text);
  background: var(--bg-alt);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 6px 10px;
}

button {
  cursor: pointer;
}

button:hover {
  border-color: var(--accent);
}

button.danger:hover {
  border-color: var(--danger);
  color: var(--danger);
}

button.primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

.error {
  color: var(--error);
  min-height: 1.2em;
  margin: 4px 0 0;
  font-size: 13px;
}

/* --- login --- */
.overlay {
  position: fixed;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg);
  z-index: 10;
}

.login-box {
  display: flex;
  flex-direction: column;
  gap: 10px;
  width: 280px;
}

.login-box h1 {
  text-align: center;
  margin: 0 0 10px;
}

/* --- generic modal (replaces window.prompt/confirm) --- */
.modal-box {
  display: flex;
  flex-direction: column;
  gap: 10px;
  width: 320px;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px;
}

.modal-box p {
  margin: 0;
}

.modal-actions {
  display: flex;
  justify-content: flex-end;
  gap: 8px;
}

/* --- app layout --- */
#app {
  display: flex;
  height: 100vh;
}

#sidebar {
  width: 280px;
  flex-shrink: 0;
  background: var(--bg-alt);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  overflow-y: auto;
}

#sidebar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px;
}

#sidebar-header h1 {
  font-size: 18px;
  margin: 0;
}

#sidebar-actions {
  display: flex;
  gap: 6px;
  padding: 0 12px 12px;
  flex-wrap: wrap;
}

#sidebar-actions button {
  flex: 1;
  font-size: 12px;
  padding: 6px 4px;
}

#tree {
  flex: 1;
  padding: 4px 8px 20px;
}

.tree-folder, .tree-item {
  border-radius: var(--radius);
}

.tree-folder-header {
  display: flex;
  align-items: center;
  gap: 4px;
  padding: 6px 6px;
  cursor: pointer;
  border-radius: var(--radius);
}

.tree-folder-header:hover, .tree-item:hover {
  background: var(--panel);
}

.tree-folder-header.dragging,
.tree-item.dragging {
  opacity: 0.4;
}

.tree-folder-header.drag-over {
  outline: 1px dashed var(--accent);
  outline-offset: -1px;
}

.tree-folder-children {
  margin-left: 14px;
  border-left: 1px solid var(--border);
  padding-left: 6px;
}

.tree-item {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 6px 8px;
  cursor: pointer;
  font-size: 13px;
}

.tree-item.active {
  background: var(--accent-dim);
}

.tree-item .kind-badge {
  font-size: 10px;
  color: var(--text-dim);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 1px 4px;
}

.tree-row-actions {
  margin-left: auto;
  display: none;
  gap: 4px;
}

.tree-folder-header:hover .tree-row-actions,
.tree-item:hover .tree-row-actions {
  display: flex;
}

.tree-row-actions button {
  padding: 2px 6px;
  font-size: 11px;
}

/* --- main --- */
#main {
  flex: 1;
  overflow-y: auto;
  padding: 24px 32px;
}

#empty-state {
  color: var(--text-dim);
  text-align: center;
  margin-top: 100px;
}

.view {
  max-width: 760px;
  margin: 0 auto;
}

.view-header {
  display: flex;
  gap: 8px;
  align-items: center;
  margin-bottom: 20px;
}

.name-input {
  flex: 1;
  font-size: 18px;
  font-weight: 600;
}

/* --- lock button --- */
#calc-lock-toggle.locked {
  background: var(--accent-dim);
  border-color: var(--accent);
}

/* --- calculator lines (edit / unlocked view) --- */
.calc-line {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 8px;
  background: var(--panel);
}

.calc-line.role-input {
  border-color: var(--accent-dim);
}

.calc-line.role-output {
  border-color: #3f6b4a;
}

.calc-line.dragging {
  opacity: 0.4;
}

.calc-line.drag-over {
  border-color: var(--accent);
  border-style: dashed;
}

.drag-handle {
  cursor: grab;
  color: var(--text-dim);
  padding: 0 2px;
  flex-shrink: 0;
  user-select: none;
  line-height: 1;
}

.drag-handle:active {
  cursor: grabbing;
}

.calc-line math-field {
  flex: 1;
  min-width: 0;
  --contains-highlight-background-color: var(--accent-dim);
}

.calc-line .line-result {
  min-width: 70px;
  text-align: right;
  color: var(--accent);
  font-variant-numeric: tabular-nums;
  font-size: 13px;
}

.calc-line .line-result.line-error {
  color: var(--error);
  font-size: 12px;
}

.calc-line .role-select {
  font-size: 12px;
  padding: 4px 6px;
  flex-shrink: 0;
}

.calc-line .role-label-input {
  width: 110px;
  flex-shrink: 0;
  font-size: 13px;
}

.calc-line .role-var-input {
  width: 60px;
  flex-shrink: 0;
  font-size: 13px;
}

.calc-line label.hidden-check {
  display: flex;
  align-items: center;
  gap: 4px;
  font-size: 12px;
  color: var(--text-dim);
  flex-shrink: 0;
  white-space: nowrap;
}

.calc-line .line-actions {
  display: flex;
  gap: 2px;
  flex-shrink: 0;
}

.calc-line .line-actions button {
  padding: 4px 6px;
  font-size: 12px;
}

#calc-add-line {
  margin-top: 4px;
}

/* --- locked / clean view --- */
.locked-item {
  display: flex;
  flex-direction: column;
  gap: 6px;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 16px;
  margin-bottom: 10px;
}

.locked-item.locked-output {
  border-color: #3f6b4a;
}

.locked-item.locked-input {
  border-color: var(--accent-dim);
}

.locked-label {
  color: var(--text-dim);
  font-size: 13px;
}

.locked-input math-field {
  font-size: 20px;
  padding: 8px 10px;
}

.locked-output-value {
  font-size: 26px;
  font-weight: 600;
  color: var(--accent);
}

.locked-output-value.line-error {
  font-size: 14px;
  color: var(--error);
  font-weight: normal;
}

.locked-plain-line {
  display: flex;
  align-items: center;
  gap: 10px;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 8px;
  margin-bottom: 8px;
}

.locked-plain-line math-field {
  flex: 1;
  min-width: 0;
}

.locked-plain-line .line-result {
  min-width: 70px;
  text-align: right;
  color: var(--accent);
  font-size: 13px;
}

math-field {
  display: block;
  background: var(--bg-alt);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
}