:root {
  --bg: #eef4f6;
  --surface: #ffffff;
  --surface-2: #f1f5f7;
  --border: #d8e0e6;
  --border-strong: #b8c4cc;
  --text: #0f172a;
  --text-dim: #64748b;
  --accent: #6366f1;
  --accent-hover: #4f46e5;
  --accent-soft: #eef2ff;
  --success: #059669;
  --danger: #dc2626;
  --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.05);
  --shadow-md: 0 4px 14px rgba(15, 23, 42, 0.08);
  --shadow-lg: 0 12px 32px rgba(15, 23, 42, 0.10);
  --diff-add-color: #065f46;
  --diff-add-bg: rgba(16, 185, 129, 0.14);
  --diff-del-color: #991b1b;
  --diff-del-bg: rgba(220, 38, 38, 0.10);
  --backdrop: rgba(15, 23, 42, 0.35);
}

[data-theme="dark"] {
  --bg: #0b1220;
  --surface: #131a2a;
  --surface-2: #1c2438;
  --border: #2a3450;
  --border-strong: #3d4a6a;
  --text: #e7eaf3;
  --text-dim: #93a0bf;
  --accent: #818cf8;
  --accent-hover: #a5b4fc;
  --accent-soft: rgba(129, 140, 248, 0.16);
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.35);
  --shadow-md: 0 4px 14px rgba(0, 0, 0, 0.40);
  --shadow-lg: 0 12px 32px rgba(0, 0, 0, 0.50);
  --diff-add-color: #6ee7b7;
  --diff-add-bg: rgba(16, 185, 129, 0.18);
  --diff-del-color: #fca5a5;
  --diff-del-bg: rgba(248, 113, 113, 0.16);
  --backdrop: rgba(0, 0, 0, 0.55);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica,
    Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji";
  font-size: 14px;
  line-height: 1.5;
}

body {
  display: grid;
  grid-template-columns: 240px 1fr;
  height: 100vh;
  overflow: hidden;
}

/* ---------- Sidebar ---------- */
.sidebar {
  background: var(--surface);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  padding: 16px 0;
  position: sticky;
  top: 0;
  height: 100vh;
}

.brand {
  display: flex;
  align-items: center;
  gap: 9px;
  padding: 6px 18px 18px;
  font-size: 18px;
  font-weight: 650;
  letter-spacing: -0.1px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 10px;
  color: var(--text);
  text-decoration: none;
  transition: color 0.12s ease;
}

.brand:hover { color: var(--accent); }

.brand-icon { font-size: 20px; }

.nav {
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 8px;
  flex: 1;
  overflow-y: auto;
  scrollbar-width: none;
}
.nav::-webkit-scrollbar { display: none; }

.nav a {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 9px 12px;
  border-radius: 8px;
  color: var(--text-dim);
  text-decoration: none;
  font-size: 14px;
  font-weight: 550;
  transition: background 0.12s ease, color 0.12s ease;
}

.nav-label { flex: 1 1 auto; }

.nav-chevron {
  font-size: 16px;
  line-height: 1;
  color: var(--text-dim);
  transition: transform 0.15s ease, color 0.15s ease;
}

.nav a.active .nav-chevron {
  transform: rotate(90deg);
  color: var(--text);
}

.nav a:hover {
  background: var(--surface-2);
  color: var(--text);
}

.nav a.active {
  background: var(--accent-soft);
  color: var(--text);
  font-weight: 600;
}

.nav-sub {
  display: flex;
  flex-direction: column;
  gap: 1px;
  margin: 2px 0 8px 16px;
  padding-left: 10px;
  border-left: 1px solid var(--border);
}

.nav-sub-section {
  font-size: 10px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-dim);
  padding: 8px 6px 2px;
}

.nav-sub-btn {
  background: transparent;
  border: none;
  text-align: left;
  padding: 4px 8px;
  font-size: 12.5px;
  color: var(--text-dim);
  cursor: pointer;
  border-radius: 6px;
  font-family: inherit;
  line-height: 1.35;
  transition: background 0.1s ease, color 0.1s ease;
}

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

.nav-sub-btn:active {
  background: var(--accent-soft);
}

.nav-icon {
  width: 18px;
  text-align: center;
  font-size: 14px;
}

.sidebar-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  color: var(--text-dim);
  font-size: 12px;
  padding: 10px 14px 10px 18px;
  border-top: 1px solid var(--border);
}

.theme-toggle {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text-dim);
  border-radius: 6px;
  width: 28px;
  height: 28px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: 14px;
  line-height: 1;
  padding: 0;
  transition: background 0.12s ease, color 0.12s ease, border-color 0.12s ease;
}

.theme-toggle:hover {
  background: var(--surface-2);
  color: var(--text);
  border-color: var(--border-strong);
}

.theme-toggle-icon { display: none; }
.theme-toggle [data-icon-light] { display: inline; }
[data-theme="dark"] .theme-toggle [data-icon-light] { display: none; }
[data-theme="dark"] .theme-toggle [data-icon-dark] { display: inline; }

/* ---------- Main ---------- */
.main {
  padding: 24px 28px;
  width: 100%;
  height: 100vh;
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.page-header {
  margin-bottom: 14px;
  flex: 0 0 auto;
}

.page-title {
  margin: 0 0 4px;
  font-size: 22px;
  font-weight: 600;
}

.page-subtitle {
  margin: 0;
  color: var(--text-dim);
}

/* ---------- Feature shared ---------- */
#feature-root {
  flex: 1 1 auto;
  min-height: 0;
  display: flex;
  flex-direction: column;
}

.editor {
  display: flex;
  flex-direction: column;
  gap: 12px;
  flex: 1 1 auto;
  min-height: 0;
}

.textarea-wrap {
  position: relative;
  flex: 1 1 auto;
  min-height: 0;
  display: flex;
}

textarea.tw-textarea {
  width: 100%;
  flex: 1 1 auto;
  resize: none;
  background: var(--surface);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 14px 16px;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 13.5px;
  line-height: 1.55;
  outline: none;
  box-shadow: var(--shadow-sm);
  transition: border-color 0.12s ease, box-shadow 0.12s ease,
    background 0.12s ease;
  white-space: pre;
  overflow: auto;
}

textarea.tw-textarea::placeholder {
  color: var(--text-dim);
  opacity: 0.7;
}

textarea.tw-textarea:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.18);
}

textarea.tw-textarea.is-placeholder {
  color: var(--text-dim);
  font-style: italic;
}

.textarea-wrap.is-drag-over textarea.tw-textarea {
  border-color: var(--accent);
  background: rgba(99, 102, 241, 0.08);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.20);
}

.drop-hint {
  position: absolute;
  inset: 0;
  display: none;
  align-items: center;
  justify-content: center;
  border-radius: 10px;
  background: rgba(99, 102, 241, 0.10);
  border: 2px dashed var(--accent);
  color: var(--accent-hover);
  font-weight: 600;
  font-size: 15px;
  pointer-events: none;
  z-index: 2;
}

.textarea-wrap.is-drag-over .drop-hint { display: flex; }

.button-row {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 8px;
  max-height: 45vh;
  overflow-y: auto;
  scrollbar-width: none;
}
.button-row::-webkit-scrollbar { display: none; }

.btn-section {
  flex-basis: 100%;
  color: var(--text-dim);
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.6px;
  margin: 8px 0 0;
  padding-top: 6px;
  border-top: 1px solid var(--border);
}
.btn-section:first-child {
  margin-top: 0;
  padding-top: 0;
  border-top: none;
}

.btn {
  background: var(--surface);
  color: var(--text);
  border: 1px solid var(--border);
  padding: 8px 14px;
  border-radius: 8px;
  cursor: pointer;
  font-size: 13px;
  font-weight: 500;
  transition: background 0.12s ease, border-color 0.12s ease,
    transform 0.05s ease;
}

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

.btn:active { transform: translateY(1px); }

.btn-primary {
  background: var(--accent);
  border-color: var(--accent);
  color: white;
}

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

.btn-ghost {
  background: transparent;
}

.toolbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.toolbar-left, .toolbar-right {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.stats {
  color: var(--text-dim);
  font-size: 12px;
}

.toast {
  position: fixed;
  bottom: 20px;
  right: 20px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  color: var(--text);
  padding: 10px 14px;
  border-radius: 8px;
  font-size: 13px;
  box-shadow: var(--shadow-md);
  opacity: 0;
  transform: translateY(10px);
  transition: opacity 0.18s ease, transform 0.18s ease;
  pointer-events: none;
  z-index: 1000;
}

.toast.show {
  opacity: 1;
  transform: translateY(0);
}

/* ---------- Whitespace options ---------- */
.options {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  padding: 12px 14px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
}

.option {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  color: var(--text-dim);
  cursor: pointer;
  user-select: none;
}

.option input { accent-color: var(--accent); }

.option:hover { color: var(--text); }

/* ---------- Diff ---------- */
.diff-layout {
  display: flex;
  flex-direction: column;
  gap: 10px;
  flex: 1 1 auto;
  min-height: 0;
}

.diff-panes {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  flex: 1 1 auto;
  min-height: 0;
}

.diff-pane {
  display: flex;
  flex-direction: column;
  min-height: 0;
}

.diff-pane-label {
  font-size: 12px;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 4px;
}

.diff-pane textarea {
  flex: 1 1 auto;
  min-height: 0;
}

.diff-toolbar {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
}

.diff-output {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 10px 14px;
  margin: 0;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 13px;
  line-height: 1.55;
  white-space: pre;
  overflow: auto;
  flex: 1 1 33%;
  min-height: 120px;
  max-height: 40vh;
}

.diff-output span { display: block; }
.diff-add  { color: var(--diff-add-color); background: var(--diff-add-bg); }
.diff-del  { color: var(--diff-del-color); background: var(--diff-del-bg); }
.diff-same { color: var(--text-dim); }
.diff-empty { color: var(--text-dim); font-style: italic; }

@media (max-width: 760px) {
  .diff-panes { grid-template-columns: 1fr; }
}

/* ---------- Save dialog ---------- */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background: var(--backdrop);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 2000;
  opacity: 0;
  transition: opacity 0.12s ease;
}

.modal-backdrop.show { opacity: 1; }

.modal {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  width: min(440px, 92vw);
  padding: 18px 20px 16px;
  box-shadow: var(--shadow-lg);
}

.modal h2 {
  margin: 0 0 14px;
  font-size: 16px;
  font-weight: 600;
}

.modal-row {
  display: flex;
  gap: 8px;
  margin-bottom: 14px;
}

.modal-row .tw-input {
  flex: 1 1 auto;
}

.modal-fields {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 14px;
}

.modal-field {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.modal-field-label {
  font-size: 12px;
  color: var(--text-dim);
}

.btn[disabled] {
  opacity: 0.4;
  cursor: not-allowed;
}
.btn[disabled]:hover {
  background: var(--surface);
  border-color: var(--border);
}

.tw-input, .tw-select {
  background: var(--surface-2);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 8px 10px;
  font-size: 13.5px;
  font-family: inherit;
  outline: none;
  transition: border-color 0.12s ease, box-shadow 0.12s ease;
}

.tw-input:focus, .tw-select:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.18);
}

.tw-select { padding-right: 28px; }

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

/* ---------- Standalone legal pages (privacy.html etc.) ---------- */
.legal-body {
  display: block;
  height: auto;
  overflow: auto;
  padding: 32px 20px 80px;
}

.legal {
  max-width: 720px;
  margin: 0 auto;
  color: var(--text);
  font-size: 15px;
  line-height: 1.65;
}

.legal h1 {
  font-size: 28px;
  font-weight: 650;
  margin: 0 0 6px;
}
.legal h2 { font-size: 18px; margin: 28px 0 8px; }
.legal h3 { font-size: 15px; margin: 18px 0 4px; }

.legal .legal-meta {
  color: var(--text-dim);
  font-size: 13px;
  margin: 0 0 24px;
}

.legal a { color: var(--accent); }
.legal a:hover { color: var(--accent-hover); }

.legal-back {
  display: inline-block;
  margin-bottom: 16px;
  color: var(--text-dim);
  text-decoration: none;
  font-size: 13px;
}
.legal-back:hover { color: var(--text); }

.legal code {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 1px 5px;
  font-size: 0.9em;
}

.legal ul { padding-left: 22px; }
.legal li { margin: 4px 0; }

/* ---------- Sidebar footer privacy link ---------- */
.sidebar-footer .footer-link {
  color: var(--text-dim);
  text-decoration: none;
  font-size: 12px;
}
.sidebar-footer .footer-link:hover { color: var(--text); }

/* ---------- Responsive ---------- */
@media (max-width: 760px) {
  body {
    grid-template-columns: 1fr;
    height: auto;
    overflow: auto;
  }
  .sidebar {
    position: static;
    height: auto;
    border-right: none;
    border-bottom: 1px solid var(--border);
  }
  .main {
    padding: 16px;
    height: auto;
  }
  .textarea-wrap { min-height: 50vh; }
}