:root {
  color-scheme: light dark;
  --font: system-ui, -apple-system, "Segoe UI", "Hiragino Sans", "Yu Gothic UI", "Yu Gothic", sans-serif;
  --font-mono: ui-monospace, "Cascadia Code", "SF Mono", Menlo, monospace;

  --bg: #f8f9fc;
  --bg-elevated: #ffffff;
  --bg-soft: #f0f2f7;
  --bg-muted: #e8ebf2;

  --text: #1a1d26;
  --text-secondary: #5c6370;
  --text-muted: #8b929e;

  --border: #e2e6ef;
  --border-strong: #cdd3df;

  --accent: #3d5afe;
  --accent-hover: #2f4be0;
  --accent-soft: rgba(61, 90, 254, 0.1);
  --accent-ring: rgba(61, 90, 254, 0.35);

  --danger: #d9304f;
  --danger-soft: rgba(217, 48, 79, 0.1);

  --shadow-sm: 0 1px 2px rgba(20, 28, 50, 0.06);
  --shadow-md: 0 4px 16px rgba(20, 28, 50, 0.08);
  --shadow-lg: 0 12px 40px rgba(20, 28, 50, 0.12);

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;

  --topbar-h: auto;
  --mobile-save-h: 0px;
  --safe-top: env(safe-area-inset-top, 0px);
  --safe-bottom: env(safe-area-inset-bottom, 0px);
  --safe-left: env(safe-area-inset-left, 0px);
  --safe-right: env(safe-area-inset-right, 0px);

  font-family: var(--font);
}

* { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
}

body {
  margin: 0;
  color: var(--text);
  background: var(--bg);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

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

.layout {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  min-height: 100dvh;
}

.main {
  flex: 1;
  display: flex;
  min-height: 0;
}

/* ---- topbar ---- */

.topbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--bg-elevated);
  border-bottom: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
  padding-top: var(--safe-top);
}

.topbar-row {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  padding: 0.65rem clamp(0.85rem, 3vw, 1.25rem);
}

.topbar-row--primary {
  gap: 0.5rem;
}

.topbar-row--secondary {
  flex-wrap: wrap;
  padding-top: 0;
  padding-bottom: 0.75rem;
  border-top: 1px solid transparent;
}

.app-title {
  font-size: 1.05rem;
  font-weight: 700;
  margin: 0;
  letter-spacing: -0.02em;
}

.app-subtitle {
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--text-muted);
  padding: 0.15rem 0.45rem;
  background: var(--bg-soft);
  border-radius: 999px;
}

.viewer-link {
  margin-left: auto;
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--accent);
  text-decoration: none;
  padding: 0.35rem 0.65rem;
  border-radius: var(--radius-sm);
  transition: background 0.15s;
}
.viewer-link:hover { background: var(--accent-soft); }

.menu-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 2.5rem;
  height: 2.5rem;
  padding: 0;
  border: none;
  background: transparent;
  border-radius: var(--radius-sm);
  cursor: pointer;
}
.menu-toggle:hover { background: var(--bg-soft); }
.menu-toggle-bar {
  display: block;
  width: 1.15rem;
  height: 2px;
  margin: 0 auto;
  background: var(--text);
  border-radius: 1px;
  transition: transform 0.2s, opacity 0.2s;
}
.menu-toggle[aria-expanded="true"] .menu-toggle-bar:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}
.menu-toggle[aria-expanded="true"] .menu-toggle-bar:nth-child(2) { opacity: 0; }
.menu-toggle[aria-expanded="true"] .menu-toggle-bar:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

.list-switcher {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  flex: 1;
  min-width: 0;
}
.list-switcher label {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--text-secondary);
  white-space: nowrap;
}
.list-switcher select {
  flex: 1;
  min-width: 0;
  max-width: 16rem;
}

.topbar-tools {
  display: flex;
  gap: 0.4rem;
  flex-wrap: wrap;
}

/* ---- panes ---- */

.word-table-pane {
  flex: 1 1 42%;
  min-width: 0;
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  background: var(--bg-elevated);
}

.edit-pane {
  flex: 1 1 58%;
  min-width: 0;
  overflow: auto;
  -webkit-overflow-scrolling: touch;
  background: var(--bg);
  padding: 0 clamp(0.85rem, 3vw, 1.25rem) calc(1.5rem + var(--mobile-save-h) + var(--safe-bottom));
}

.edit-pane[hidden] { display: none !important; }

.pane-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
  padding: 0.85rem clamp(0.85rem, 3vw, 1.25rem) 0.6rem;
  position: sticky;
  top: 0;
  background: var(--bg-elevated);
  z-index: 10;
  border-bottom: 1px solid var(--border);
}

.edit-pane .pane-header {
  background: var(--bg);
  margin: 0 calc(-1 * clamp(0.85rem, 3vw, 1.25rem));
  padding-left: clamp(0.85rem, 3vw, 1.25rem);
  padding-right: clamp(0.85rem, 3vw, 1.25rem);
}

.pane-header h2 {
  font-size: 0.95rem;
  font-weight: 650;
  margin: 0;
  letter-spacing: -0.01em;
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.pane-header--edit h2 { flex: 1; }

.pane-header-actions,
.edit-actions {
  display: flex;
  gap: 0.35rem;
  flex-wrap: wrap;
  align-items: center;
}

.back-btn {
  display: none;
  flex-shrink: 0;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent);
  background: var(--accent-soft);
  border: none;
  border-radius: var(--radius-sm);
  padding: 0.4rem 0.65rem;
  cursor: pointer;
}
.back-btn:hover { background: rgba(61, 90, 254, 0.16); }

.desktop-only { display: inline-flex; }

/* ---- word table ---- */

.table-scroll {
  flex: 1;
  overflow: auto;
  -webkit-overflow-scrolling: touch;
}

.word-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}

.word-table th {
  position: sticky;
  top: 0;
  z-index: 2;
  background: var(--bg-soft);
  font-size: 0.72rem;
  font-weight: 650;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-muted);
  padding: 0.55rem 0.85rem;
  border-bottom: 1px solid var(--border);
  text-align: left;
}

.word-table td {
  padding: 0.6rem 0.85rem;
  border-bottom: 1px solid var(--border);
  text-align: left;
  vertical-align: middle;
}

.word-table .col-no {
  width: 3.5rem;
  font-variant-numeric: tabular-nums;
  font-size: 0.82rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

.word-table .col-pron {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--text-secondary);
}

.word-table tbody tr:not(.section-header-row) {
  cursor: pointer;
  transition: background 0.12s;
}
.word-table tbody tr:not(.section-header-row):hover { background: var(--bg-soft); }
.word-table tbody tr.selected { background: var(--accent-soft); }
.word-table tbody tr.selected td:first-child { color: var(--accent); font-weight: 600; }

.word-table tbody tr.branch-row td:nth-child(2) {
  padding-left: 1.5rem;
  color: var(--text-secondary);
}
.word-table tbody tr.branch-row td:nth-child(2)::before {
  content: "└ ";
  color: var(--text-muted);
  font-size: 0.75rem;
}

.word-table tbody tr.section-header-row {
  cursor: default;
  background: var(--bg-soft);
}
.word-table tbody tr.section-header-row td {
  font-weight: 650;
  font-size: 0.78rem;
  color: var(--text-secondary);
  padding: 0.45rem 0.85rem;
  letter-spacing: 0.02em;
}

.empty-msg {
  padding: 2rem 1.25rem;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.9rem;
}

/* ---- buttons & inputs ---- */

button {
  border: 1px solid var(--border-strong);
  background: var(--bg-elevated);
  border-radius: var(--radius-sm);
  padding: 0.45rem 0.85rem;
  cursor: pointer;
  font-size: 0.85rem;
  font-weight: 500;
  font-family: inherit;
  color: var(--text);
  transition: background 0.12s, border-color 0.12s, box-shadow 0.12s;
  min-height: 2.25rem;
  touch-action: manipulation;
}
button:hover { background: var(--bg-soft); }
button:focus-visible {
  outline: 2px solid var(--accent-ring);
  outline-offset: 2px;
}
button:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

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

button.danger { color: var(--danger); border-color: rgba(217, 48, 79, 0.35); }
button.danger:hover { background: var(--danger-soft); }

.btn-ghost {
  background: transparent;
  border-color: transparent;
  color: var(--text-secondary);
}
.btn-ghost:hover {
  background: var(--bg-soft);
  color: var(--text);
}

.btn-compact { padding: 0.45rem 0.65rem; white-space: nowrap; }

input[type="text"],
input[type="number"],
select,
textarea {
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-sm);
  padding: 0.5rem 0.65rem;
  font-size: 1rem;
  font-family: inherit;
  color: var(--text);
  background: var(--bg-elevated);
  transition: border-color 0.15s, box-shadow 0.15s;
  width: 100%;
  min-height: 2.5rem;
}
input:focus-visible,
select:focus-visible,
textarea:focus-visible {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-ring);
}

select { cursor: pointer; }
textarea { resize: vertical; min-height: 4.5rem; line-height: 1.55; }

/* ---- form sections ---- */

.word-form { padding-top: 0.25rem; }

fieldset {
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  margin: 0.85rem 0;
  padding: 0.85rem 1rem 1rem;
  background: var(--bg-elevated);
  box-shadow: var(--shadow-sm);
}

legend {
  font-size: 0.82rem;
  font-weight: 650;
  padding: 0 0.35rem;
  color: var(--text);
}

legend .hint {
  font-weight: 400;
  color: var(--text-muted);
  font-size: 0.72rem;
  margin-left: 0.35rem;
}

.field-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 200px), 1fr));
  gap: 0.75rem;
  margin-top: 0.5rem;
}

.field-row label {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.field-row label .hint {
  font-weight: 400;
  color: var(--text-muted);
  font-size: 0.72rem;
}

.input-with-btn {
  display: flex;
  gap: 0.35rem;
  align-items: stretch;
}
.input-with-btn input { flex: 1; min-width: 0; }
.input-with-btn button {
  flex: 0 0 auto;
  min-width: 2.5rem;
  padding: 0.35rem 0.55rem;
}

/* ---- repeat rows ---- */

.repeat-list { display: flex; flex-direction: column; gap: 0.5rem; }

.repeat-row {
  display: grid;
  gap: 0.4rem;
  align-items: center;
  padding: 0.55rem;
  background: var(--bg-soft);
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
}

.repeat-row.sense-row {
  grid-template-columns: 5.5rem 1fr 9rem auto;
}
.repeat-row.derivative-row {
  grid-template-columns: 5.5rem 1fr 1fr auto;
}
.repeat-row.example-row {
  grid-template-columns: 1fr 1fr 1fr auto;
}

.repeat-row input {
  min-height: 2.35rem;
  font-size: 0.92rem;
  background: var(--bg-elevated);
}

.remove-row-btn {
  color: var(--danger);
  border-color: transparent;
  background: transparent;
  min-width: 2.25rem;
  min-height: 2.25rem;
  padding: 0;
  font-size: 1.1rem;
  line-height: 1;
}
.remove-row-btn:hover { background: var(--danger-soft); }

.add-row-btn {
  margin-top: 0.55rem;
  width: 100%;
  border-style: dashed;
  color: var(--text-secondary);
}
.add-row-btn:hover {
  color: var(--accent);
  border-color: var(--accent);
  background: var(--accent-soft);
}

/* ---- preview & tags ---- */

.preview {
  margin-top: 0.5rem;
  padding: 0.65rem 0.85rem;
  background: var(--bg-soft);
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  min-height: 2rem;
  line-height: 1.55;
  border: 1px solid var(--border);
}
.preview a.ref {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px dotted var(--accent);
}
.preview .ref-missing {
  color: var(--danger);
  border-bottom: 1px dotted var(--danger);
}
.preview mark {
  background: #fff3bf;
  padding: 0 0.15em;
  border-radius: 2px;
}

.tags-row {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  align-items: center;
}

.tag-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.35rem 0.65rem;
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: 999px;
  font-size: 0.82rem;
  font-weight: 500;
  cursor: pointer;
  transition: border-color 0.12s, background 0.12s;
}
.tag-chip:has(input:checked) {
  background: var(--accent-soft);
  border-color: var(--accent);
  color: var(--accent);
}
.tag-chip input { width: auto; min-height: auto; margin: 0; accent-color: var(--accent); }

.tag-select {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.82rem;
  font-weight: 500;
}
.tag-select select { width: auto; min-width: 5rem; }

.custom-tags-label {
  display: block;
  margin-top: 0.65rem;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-secondary);
}
.custom-tags-label input { margin-top: 0.3rem; }

/* ---- mobile save bar ---- */

.mobile-save-bar {
  display: none;
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  padding: 0.65rem clamp(0.85rem, 3vw, 1.25rem) calc(0.65rem + var(--safe-bottom));
  background: var(--bg-elevated);
  border-top: 1px solid var(--border);
  box-shadow: 0 -4px 20px rgba(20, 28, 50, 0.08);
  z-index: 90;
}
.mobile-save-btn { width: 100%; min-height: 2.75rem; font-size: 1rem; }

/* ---- mobile: collapsible topbar menu ---- */

@media (max-width: 768px) {
  .menu-toggle { display: flex; }

  .topbar-row--secondary {
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0.65rem;
    padding-top: 0;
    border-top-color: var(--border);
  }
  .topbar-row--secondary.is-open { display: flex; }

  .list-switcher {
    flex-wrap: wrap;
  }
  .list-switcher select {
    flex: 1 1 100%;
    max-width: none;
  }

  .topbar-tools {
    flex-direction: column;
  }
  .topbar-tools button { width: 100%; }

  /* single-pane mode when editing */
  .layout--editor .word-table-pane { display: none; }
  .layout--editor .edit-pane {
    flex: 1;
    display: flex !important;
    flex-direction: column;
  }

  .back-btn { display: inline-flex; align-items: center; }
  .desktop-only { display: none !important; }

  .pane-header {
    flex-wrap: wrap;
    padding-top: 0.65rem;
    padding-bottom: 0.65rem;
  }
  .pane-header--edit {
    display: grid;
    grid-template-columns: auto 1fr;
    grid-template-rows: auto auto;
    gap: 0.5rem;
  }
  .pane-header--edit .back-btn { grid-row: 1; grid-column: 1; }
  .pane-header--edit h2 { grid-row: 1; grid-column: 2; }
  .pane-header--edit .edit-actions {
    grid-row: 2;
    grid-column: 1 / -1;
    width: 100%;
  }
  .pane-header--edit .edit-actions button { flex: 1; min-width: 0; }

  .pane-header-actions {
    width: 100%;
  }
  .pane-header-actions button { flex: 1; min-width: 0; }

  .word-table .col-pron { display: none; }

  .repeat-row.sense-row,
  .repeat-row.derivative-row,
  .repeat-row.example-row {
    grid-template-columns: 1fr auto;
  }
  .repeat-row .pos { grid-column: 1; }
  .repeat-row .meaning,
  .repeat-row .word,
  .repeat-row .sentence { grid-column: 1; }
  .repeat-row .pronunciation,
  .repeat-row .answer,
  .repeat-row .translation { grid-column: 1; }
  .repeat-row .remove-row-btn {
    grid-column: 2;
    grid-row: 1 / -1;
    align-self: start;
  }

  .mobile-save-bar {
    display: none;
  }
  .layout--editor .mobile-save-bar {
    display: block;
  }
  :root { --mobile-save-h: 4.5rem; }

  .layout--editor .edit-pane {
    padding-bottom: calc(5.5rem + var(--safe-bottom));
  }
}

@media (max-width: 480px) {
  .app-subtitle { display: none; }

  .viewer-link {
    font-size: 0.78rem;
    padding: 0.3rem 0.5rem;
  }

  .pane-header h2 { font-size: 0.88rem; }

  button { font-size: 0.82rem; }
}

/* ---- tablet: stack panes ---- */

@media (max-width: 900px) and (min-width: 769px) {
  .main { flex-direction: column; }
  .word-table-pane {
    flex: none;
    max-height: 45vh;
    border-right: none;
    border-bottom: 1px solid var(--border);
  }
}

/* ---- dark mode ---- */

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #12141a;
    --bg-elevated: #1a1d26;
    --bg-soft: #22262f;
    --bg-muted: #2a2f3a;

    --text: #eceef3;
    --text-secondary: #a8afbd;
    --text-muted: #6e7585;

    --border: #2e3340;
    --border-strong: #3d4454;

    --accent: #6b8aff;
    --accent-hover: #5a7af5;
    --accent-soft: rgba(107, 138, 255, 0.14);
    --accent-ring: rgba(107, 138, 255, 0.35);

    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.25);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.35);
    --shadow-lg: 0 12px 40px rgba(0, 0, 0, 0.45);
  }

  .preview mark { background: #5c4d1a; color: #fff3bf; }
}

/* ---- reduced motion ---- */

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    transition-duration: 0.01ms !important;
  }
}