:root {
  --font-body: "Segoe UI Variable Text", "Aptos", "Trebuchet MS", sans-serif;
  --font-display: "Cambria", "Georgia", serif;
  --radius-large: 24px;
  --radius-medium: 16px;
  --radius-small: 10px;
  --shadow-soft: 0 22px 60px rgba(24, 38, 47, 0.12);
  --shadow-line: 0 0 0 1px rgba(24, 38, 47, 0.08);
  --background: #f3efe6;
  --background-accent: #efe3d2;
  --panel: rgba(255, 250, 243, 0.88);
  --panel-strong: #fff8ef;
  --panel-muted: #f8efe3;
  --text-main: #1f2a33;
  --text-soft: #5f6d76;
  --text-inverse: #fefaf3;
  --border: rgba(31, 42, 51, 0.12);
  --primary: #b7844d;
  --primary-strong: #9e6e39;
  --success: #2f7a59;
  --danger: #a64545;
  --chip: rgba(183, 132, 77, 0.14);
  --overlay: rgba(26, 34, 40, 0.52);
}

body.theme-dark {
  --background: #141a1f;
  --background-accent: #1c242c;
  --panel: rgba(25, 33, 41, 0.9);
  --panel-strong: #1d2730;
  --panel-muted: #182028;
  --text-main: #f4eee5;
  --text-soft: #b6c0c6;
  --text-inverse: #10202a;
  --border: rgba(244, 238, 229, 0.12);
  --primary: #d4a161;
  --primary-strong: #e1b47d;
  --success: #6eb68c;
  --danger: #df8181;
  --chip: rgba(212, 161, 97, 0.16);
  --overlay: rgba(4, 7, 10, 0.7);
  --shadow-soft: 0 22px 60px rgba(0, 0, 0, 0.34);
  --shadow-line: 0 0 0 1px rgba(255, 250, 243, 0.06);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  min-height: 100%;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font-body);
  color: var(--text-main);
  background:
    radial-gradient(circle at top left, rgba(212, 161, 97, 0.22), transparent 28%),
    radial-gradient(circle at bottom right, rgba(47, 122, 89, 0.12), transparent 24%),
    linear-gradient(180deg, var(--background) 0%, var(--background-accent) 100%);
}

button,
input,
select {
  font: inherit;
}

button {
  cursor: pointer;
}

.app-shell {
  width: min(1180px, calc(100% - 32px));
  margin: 0 auto;
  padding: 28px 0 40px;
}

.topbar,
.panel,
.session-screen,
.modal-card {
  backdrop-filter: blur(10px);
}

.topbar {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: flex-start;
  padding: 20px 24px;
  border-radius: var(--radius-large);
  background: var(--panel);
  box-shadow: var(--shadow-soft), var(--shadow-line);
}

.eyebrow {
  margin: 0 0 6px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  font-size: 0.75rem;
  color: var(--text-soft);
}

h1,
h2 {
  margin: 0;
  font-family: var(--font-display);
}

h1 {
  font-size: clamp(2rem, 4vw, 3rem);
}

h2 {
  font-size: clamp(1.45rem, 3vw, 2rem);
}

.topbar-status,
.panel-header p,
.status-message,
.import-copy,
.session-meta p,
.collection-meta,
.empty-state,
.table-note {
  margin: 0;
  color: var(--text-soft);
}

.main-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin: 18px 0;
}

.nav-chip,
.button,
.icon-button {
  border: 0;
  border-radius: 999px;
  transition: transform 160ms ease, background-color 160ms ease, color 160ms ease, opacity 160ms ease;
}

.nav-chip {
  padding: 12px 18px;
  background: var(--chip);
  color: var(--text-main);
}

.nav-chip:hover,
.button:hover,
.icon-button:hover,
.flashcard:hover {
  transform: translateY(-1px);
}

.nav-chip.is-active {
  background: var(--primary);
  color: var(--text-inverse);
}

.panel,
.session-screen {
  border-radius: var(--radius-large);
  background: var(--panel);
  box-shadow: var(--shadow-soft), var(--shadow-line);
  padding: 24px;
}

.main-layout {
  display: grid;
  gap: 20px;
}

.panel-header,
.session-topbar,
.session-progress,
.summary-actions,
.modal-actions {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: center;
}

.collection-grid {
  display: grid;
  gap: 18px;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  margin-top: 20px;
}

.collection-card,
.stats-card,
.import-card,
.settings-card,
.flashcard,
.summary-grid > article {
  border-radius: var(--radius-medium);
  background: var(--panel-strong);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-line);
}

.collection-card,
.import-card,
.settings-card {
  padding: 18px;
}

.collection-card {
  display: grid;
  gap: 14px;
}

.collection-card-header {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: flex-start;
}

.collection-card-header h3 {
  margin: 0;
  font-size: 1.15rem;
}

.tag-row,
.collection-actions,
.stats-overview,
.summary-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.tag,
.pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 12px;
  border-radius: 999px;
  background: var(--chip);
  color: var(--text-main);
  font-size: 0.9rem;
}

.collection-actions .button,
.summary-actions .button,
.modal-actions .button {
  min-width: 132px;
}

.stats-overview {
  margin-top: 20px;
}

.stats-card,
.summary-grid > article {
  flex: 1 1 180px;
  padding: 18px;
}

.stats-card strong,
.summary-grid strong {
  display: block;
  margin-top: 10px;
  font-size: 2rem;
  font-family: var(--font-display);
}

.stats-table-wrap {
  margin-top: 22px;
  overflow-x: auto;
}

.stats-table {
  width: 100%;
  border-collapse: collapse;
  min-width: 720px;
}

.stats-table th,
.stats-table td {
  padding: 14px 12px;
  border-bottom: 1px solid var(--border);
  text-align: left;
}

.stats-table th {
  font-size: 0.85rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--text-soft);
}

.import-card,
.settings-card {
  display: grid;
  gap: 18px;
  margin-top: 20px;
}

.inline-code {
  padding: 12px 14px;
  border-radius: var(--radius-small);
  background: var(--panel-muted);
  overflow-wrap: anywhere;
  font-family: Consolas, "Courier New", monospace;
}

.theme-toggle-group {
  margin: 0;
  padding: 0;
  border: 0;
  display: grid;
  gap: 14px;
}

.radio-line,
.checkbox-line {
  display: flex;
  gap: 10px;
  align-items: center;
}

.with-inline-input {
  flex-wrap: wrap;
}

.inline-number,
.select-field {
  min-height: 42px;
  padding: 10px 12px;
  border-radius: var(--radius-small);
  border: 1px solid var(--border);
  background: var(--panel-muted);
  color: var(--text-main);
}

.button {
  padding: 12px 18px;
}

.button-small {
  min-width: 0;
  padding: 8px 14px;
}

.button:disabled {
  opacity: 0.45;
  cursor: not-allowed;
  transform: none;
}

.button-primary {
  background: var(--primary);
  color: var(--text-inverse);
}

.button-secondary {
  background: var(--panel-muted);
  color: var(--text-main);
}

.button-success {
  background: var(--success);
  color: var(--text-inverse);
}

.button-danger {
  background: var(--danger);
  color: var(--text-inverse);
}

.session-screen {
  display: grid;
  gap: 18px;
}

.session-meta {
  display: grid;
  gap: 6px;
}

.session-meta p:first-child {
  color: var(--text-main);
  font-weight: 600;
}

.session-progress {
  padding: 0 4px;
}

.flashcard {
  min-height: 340px;
  display: grid;
  place-items: center;
  text-align: center;
  padding: 28px;
  gap: 16px;
}

.flashcard-wordclass {
  margin: 0;
  font-size: 0.95rem;
  color: var(--text-soft);
}

.flashcard-term-group,
.flashcard-answer {
  display: grid;
  gap: 8px;
}

.flashcard-answer[hidden] {
  display: none;
}

.flashcard.is-revealed .flashcard-term-group {
  display: none;
}

.flashcard-term {
  margin: 0;
  font-size: clamp(2.2rem, 6vw, 4.5rem);
  line-height: 1.05;
}

.flashcard-translation {
  margin: 0;
  font-size: clamp(1.6rem, 3vw, 2.4rem);
  font-weight: 600;
}

.flashcard-note {
  margin: 10px auto 0;
  max-width: 60ch;
  color: var(--text-soft);
}

.session-actions {
  display: flex;
  justify-content: center;
  gap: 14px;
  flex-wrap: wrap;
}

.session-summary {
  display: grid;
  gap: 18px;
  padding-top: 10px;
}

.modal {
  position: fixed;
  inset: 0;
  display: grid;
  place-items: center;
  padding: 20px;
  background: var(--overlay);
}

.modal-card {
  width: min(840px, 100%);
  max-height: min(88vh, 900px);
  overflow: auto;
  padding: 22px;
  border-radius: var(--radius-large);
  background: var(--panel);
  box-shadow: var(--shadow-soft), var(--shadow-line);
  position: relative;
}

.icon-button {
  position: absolute;
  top: 14px;
  right: 14px;
  width: 42px;
  height: 42px;
  background: var(--panel-muted);
  color: var(--text-main);
  font-size: 1.6rem;
}

.modal-grid {
  display: grid;
  gap: 18px;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  margin: 22px 0;
}

.modal-grid fieldset {
  margin: 0;
  border: 1px solid var(--border);
  border-radius: var(--radius-medium);
  padding: 16px;
  display: grid;
  gap: 12px;
  min-width: 0;
}

.category-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  max-height: 200px;
  overflow: auto;
}

.category-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.category-list .checkbox-line {
  align-items: flex-start;
  min-width: 0;
}

.category-list .checkbox-line span {
  overflow-wrap: anywhere;
}

.is-hidden {
  display: none !important;
}

.empty-state {
  padding: 28px;
  text-align: center;
  border-radius: var(--radius-medium);
  background: var(--panel-strong);
  border: 1px dashed var(--border);
}

@media (max-width: 760px) {
  .app-shell {
    width: min(100% - 20px, 1180px);
    padding-top: 18px;
  }

  .topbar,
  .panel,
  .session-screen,
  .modal-card {
    padding: 18px;
  }

  .topbar,
  .panel-header,
  .session-topbar,
  .session-progress,
  .summary-actions,
  .modal-actions {
    flex-direction: column;
    align-items: stretch;
  }

  .flashcard {
    min-height: 280px;
  }

  .category-actions .button {
    flex: 1 1 0;
  }
}

@media (min-width: 761px) {
  .category-list {
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  }
}