:root {
  --ink: #1a1a1a;
  --muted: #5c5c5c;
  --paper: #f7f4ef;
  --wash: #ebe4d8;
  --accent: #c45c26;
  --accent-dark: #9a4518;
  --line: #d4cbb8;
  --error: #b42318;
  --shadow: 0 18px 50px rgba(40, 28, 12, 0.08);
  --font-jp: "Shippori Mincho", "Noto Sans JP", "Noto Sans SC", serif;
  --font-ui: "Noto Sans JP", "Noto Sans SC", sans-serif;
}

body.lang-zh {
  --font-jp: "Noto Sans SC", "Noto Sans JP", sans-serif;
  --font-ui: "Noto Sans SC", "Noto Sans JP", sans-serif;
}

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

html,
body {
  margin: 0;
  min-height: 100%;
}

body {
  font-family: var(--font-ui);
  color: var(--ink);
  background:
    radial-gradient(ellipse 80% 50% at 50% -10%, #fff8ee 0%, transparent 55%),
    linear-gradient(165deg, #f3eee5 0%, var(--paper) 40%, #e8e0d2 100%);
  background-attachment: fixed;
}

.page {
  width: min(640px, calc(100% - 2rem));
  margin: 0 auto;
  padding: 2.5rem 0 3.5rem;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  gap: 1.75rem;
}

.page[hidden],
.lang-picker[hidden] {
  display: none !important;
}

.lang-picker {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 2rem 1rem;
}

.lang-picker-inner {
  width: min(560px, 100%);
  text-align: center;
}

.lang-choices {
  margin-top: 2rem;
  display: grid;
  gap: 1rem;
}

.lang-choice {
  appearance: none;
  display: block;
  font: inherit;
  color: inherit;
  text-decoration: none;
  cursor: pointer;
  text-align: left;
  padding: 1.35rem 1.4rem;
  border: 1px solid var(--line);
  background: rgba(255, 252, 247, 0.85);
  box-shadow: var(--shadow);
  transition:
    border-color 0.2s ease,
    transform 0.15s ease;
}

.lang-choice:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}

.lang-choice-native {
  display: block;
  font-family: var(--font-jp);
  font-size: 1.8rem;
  font-weight: 700;
  line-height: 1.2;
}

.lang-choice-name {
  display: block;
  margin-top: 0.35rem;
  color: var(--muted);
  font-size: 1rem;
}

.brand-row {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1rem;
}

.brand-mark {
  margin: 0;
  font-family: var(--font-jp);
  font-size: clamp(1.85rem, 5vw, 2.4rem);
  font-weight: 700;
  letter-spacing: 0.02em;
  line-height: 1.2;
}

.brand-sub {
  margin: 0.35rem 0 0;
  color: var(--muted);
  font-size: 0.95rem;
}

.db-stats {
  margin: 0.75rem 0 0;
  font-size: 0.9rem;
  color: var(--ink);
  letter-spacing: 0.01em;
}

.db-stats strong {
  font-weight: 700;
  color: var(--accent-dark);
}

.generate-status {
  margin: 0.4rem 0 0;
  font-size: 0.85rem;
  color: var(--muted);
}

.mode-tabs {
  display: flex;
  gap: 0.5rem;
  border-bottom: 1px solid var(--line);
  padding-bottom: 0.25rem;
}

.mode-tab {
  appearance: none;
  border: 0;
  background: transparent;
  font: inherit;
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--muted);
  text-decoration: none;
  padding: 0.55rem 0.9rem;
  cursor: pointer;
  position: relative;
  transition: color 0.2s ease;
}

.mode-tab:hover {
  color: var(--ink);
}

.mode-tab.is-active {
  color: var(--accent-dark);
}

.mode-tab.is-active::after {
  content: "";
  position: absolute;
  left: 0.9rem;
  right: 0.9rem;
  bottom: -0.3rem;
  height: 2px;
  background: var(--accent);
  border-radius: 1px;
}

.level-tabs {
  display: flex;
  gap: 0.5rem;
  margin-top: -0.75rem;
}

.level-tab {
  appearance: none;
  border: 1px solid var(--line);
  background: rgba(255, 252, 247, 0.7);
  font: inherit;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--muted);
  text-decoration: none;
  padding: 0.4rem 0.85rem;
  cursor: pointer;
  transition:
    color 0.2s ease,
    border-color 0.2s ease,
    background 0.2s ease;
}

.level-tab:hover {
  color: var(--ink);
  border-color: var(--accent);
}

.level-tab.is-active {
  color: var(--accent-dark);
  border-color: var(--accent);
  background: rgba(196, 92, 38, 0.08);
}

.card-stage {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
}

.card-stage[hidden],
.grammar-panel[hidden],
.flashcard[hidden],
.grammar-detail[hidden],
.grammar-empty[hidden],
.generate-status[hidden],
.error[hidden],
.loading[hidden] {
  display: none !important;
}

.grammar-panel {
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.grammar-toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: 0.85rem;
}

.grammar-filters {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  gap: 0.75rem;
}

.grammar-filter {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  font-size: 0.85rem;
  color: var(--muted);
}

.grammar-filter select,
.grammar-filter input {
  min-width: 12rem;
  font: inherit;
  color: var(--ink);
  padding: 0.55rem 0.7rem;
  border: 1px solid var(--line);
  background: #fff;
}

.grammar-filter-text input {
  min-width: 14rem;
}

.grammar-layout {
  display: block;
  width: 100%;
}

.grammar-panel.is-reading .grammar-toolbar,
.grammar-panel.is-reading .grammar-layout {
  display: none !important;
}

.grammar-list-wrap {
  border: 1px solid var(--line);
  background: rgba(255, 252, 247, 0.72);
  padding: 0.75rem;
}

.grammar-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.grammar-item {
  appearance: none;
  width: 100%;
  text-align: left;
  border: 1px solid transparent;
  background: transparent;
  font: inherit;
  cursor: pointer;
  padding: 0.7rem 0.75rem;
  color: var(--ink);
  transition:
    background 0.15s ease,
    border-color 0.15s ease;
}

.grammar-item:hover {
  background: rgba(255, 255, 255, 0.8);
  border-color: var(--line);
}

.grammar-item.is-active {
  background: #fff;
  border-color: var(--accent);
}

.grammar-item-subject {
  display: block;
  font-size: 0.75rem;
  color: var(--muted);
  margin-bottom: 0.2rem;
}

.grammar-item-pattern {
  display: block;
  font-family: var(--font-jp);
  font-size: 1.05rem;
  font-weight: 700;
}

.grammar-empty {
  margin: 1rem 0.5rem;
  color: var(--muted);
  font-size: 0.95rem;
}

.grammar-pager {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
  margin-top: 0.75rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--line);
}

.pager-btn {
  appearance: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font: inherit;
  font-size: 0.9rem;
  padding: 0.45rem 0.85rem;
  border: 1px solid var(--line);
  background: #fff;
  color: var(--ink);
  text-decoration: none;
  cursor: pointer;
}

.pager-btn:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

.pager-label {
  font-size: 0.9rem;
  color: var(--muted);
}

.grammar-detail {
  position: fixed;
  inset: 0;
  z-index: 40;
  width: 100%;
  min-height: 100vh;
  margin: 0;
  border: 0;
  background:
    radial-gradient(ellipse 80% 50% at 50% -10%, #fff8ee 0%, transparent 55%),
    linear-gradient(165deg, #f3eee5 0%, var(--paper) 40%, #e8e0d2 100%);
  padding: 1.5rem clamp(1rem, 4vw, 3rem) 3rem;
  overflow-y: auto;
  animation: rise 0.3s ease;
}

.grammar-detail-top,
.grammar-detail-subject,
.grammar-pattern-row,
.grammar-langs,
.grammar-example {
  max-width: 720px;
  margin-left: auto;
  margin-right: auto;
}

.grammar-detail-top {
  margin-bottom: 1.25rem;
}

.grammar-detail-subject {
  margin: 0;
  font-size: 0.85rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--accent-dark);
  text-align: center;
}

.grammar-pattern-row {
  margin-top: 0.45rem;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.85rem;
  text-align: center;
}

.grammar-detail-pattern {
  margin: 0;
  font-family: var(--font-jp);
  font-size: clamp(2rem, 6vw, 2.8rem);
  font-weight: 700;
  line-height: 1.3;
  text-align: center;
}

.grammar-pattern-row .icon-btn {
  flex-shrink: 0;
}

.grammar-hl {
  background: rgba(196, 92, 38, 0.18);
  color: var(--accent-dark);
  font-weight: 700;
  padding: 0 0.12em;
  border-radius: 0.15em;
  box-decoration-break: clone;
  -webkit-box-decoration-break: clone;
}

.grammar-langs {
  margin-top: 1.75rem;
  display: grid;
  gap: 1.35rem;
}

.grammar-langs h3,
.grammar-example h3 {
  margin: 0 0 0.35rem;
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--muted);
}

.grammar-langs p {
  margin: 0;
  line-height: 1.7;
  white-space: pre-wrap;
  font-size: 1.02rem;
}

.grammar-example {
  margin-top: 1.35rem;
  padding-top: 1.1rem;
  border-top: 1px solid var(--line);
}

.example-ja {
  margin: 0;
  font-family: var(--font-jp);
  font-size: 1.25rem;
  font-weight: 700;
}

.example-romaji {
  margin: 0.35rem 0 0;
  color: var(--muted);
}

.example-tr {
  margin: 0.55rem 0 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem 0.65rem;
}

.flashcard {
  width: 100%;
  text-align: center;
  padding: 2.5rem 1.5rem 2rem;
  background: rgba(255, 252, 247, 0.72);
  border: 1px solid var(--line);
  box-shadow: var(--shadow);
  animation: rise 0.35s ease;
}

@keyframes rise {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.word-type {
  margin: 0 0 0.75rem;
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent-dark);
}

.word-type.is-missing {
  color: var(--error);
  text-transform: none;
  letter-spacing: 0.02em;
}

.japanese {
  margin: 0;
  font-family: var(--font-jp);
  font-size: clamp(2.4rem, 8vw, 3.6rem);
  font-weight: 700;
  line-height: 1.35;
  letter-spacing: 0.04em;
}

.romaji {
  margin: 0.85rem 0 0;
  font-size: 1.15rem;
  color: var(--muted);
  letter-spacing: 0.04em;
}

.translations {
  margin-top: 1.6rem;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: baseline;
  gap: 0.55rem 0.75rem;
  font-size: 1.05rem;
}

.english,
.vietnamese {
  margin: 0;
}

.sep {
  color: var(--line);
  font-weight: 700;
}

.actions {
  margin-top: 2.25rem;
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 1rem;
}

.icon-btn,
.next-btn {
  appearance: none;
  font: inherit;
  cursor: pointer;
  border: 1px solid var(--line);
  transition:
    background 0.2s ease,
    color 0.2s ease,
    border-color 0.2s ease,
    transform 0.15s ease;
}

.icon-btn {
  width: 3rem;
  height: 3rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background: #fff;
  color: var(--ink);
}

.icon-btn:hover:not(:disabled) {
  border-color: var(--accent);
  color: var(--accent-dark);
}

.icon-btn:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

.icon-btn.is-speaking {
  color: var(--accent);
  border-color: var(--accent);
  animation: pulse 1s ease infinite;
}

@keyframes pulse {
  50% {
    transform: scale(1.06);
  }
}

.next-btn {
  min-width: 7.5rem;
  height: 3rem;
  padding: 0 1.4rem;
  border-radius: 999px;
  background: var(--ink);
  color: #fff;
  border-color: var(--ink);
  font-weight: 500;
}

.next-btn:hover:not(:disabled) {
  background: var(--accent-dark);
  border-color: var(--accent-dark);
}

.next-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.loading {
  margin: 0;
  color: var(--muted);
  font-size: 1rem;
}

.error {
  width: 100%;
  margin: 0 0 1rem;
  padding: 0.85rem 1rem;
  color: var(--error);
  background: #fef3f2;
  border: 1px solid #fecdca;
  text-align: left;
  font-size: 0.95rem;
  line-height: 1.45;
}

.success {
  width: 100%;
  margin: 0 0 1rem;
  padding: 0.85rem 1rem;
  color: #027a48;
  background: #ecfdf3;
  border: 1px solid #abefc6;
  text-align: left;
  font-size: 0.95rem;
  line-height: 1.45;
}

.auth-box {
  text-align: left;
}

.auth-box .brand-mark,
.auth-box .brand-sub {
  text-align: center;
}

.auth-form {
  margin-top: 1.5rem;
  display: grid;
  gap: 1rem;
}

.auth-label {
  display: grid;
  gap: 0.4rem;
  font-size: 0.9rem;
  color: var(--muted);
  text-align: left;
}

.auth-input {
  font: inherit;
  color: var(--ink);
  padding: 0.75rem 0.9rem;
  border: 1px solid var(--line);
  background: rgba(255, 252, 247, 0.95);
  width: 100%;
}

.auth-input:focus {
  outline: 2px solid color-mix(in srgb, var(--accent) 45%, transparent);
  outline-offset: 1px;
  border-color: var(--accent);
}

.auth-submit {
  width: 100%;
  margin-top: 0.25rem;
}

.auth-nav {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
  justify-content: flex-end;
}

.auth-nav-home {
  justify-content: center;
  margin-bottom: 1.25rem;
}

.auth-user {
  font-size: 0.9rem;
  color: var(--muted);
  margin-right: 0.25rem;
}

.admin-panel {
  padding: 1.25rem 0;
  border-top: 1px solid var(--line);
}

.admin-heading {
  margin: 0 0 1rem;
  font-size: 1.1rem;
  font-weight: 600;
}

.admin-create {
  margin-top: 0;
}

.users-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.95rem;
}

.users-table th,
.users-table td {
  text-align: left;
  padding: 0.65rem 0.4rem;
  border-bottom: 1px solid var(--line);
  vertical-align: middle;
}

.users-table th {
  color: var(--muted);
  font-weight: 500;
  font-size: 0.85rem;
}

.inline-form {
  display: inline;
  margin: 0;
}

.danger-btn {
  color: var(--error);
  border-color: #fecdca;
}

@media (max-width: 480px) {
  .page {
    padding-top: 1.75rem;
  }

  .flashcard {
    padding: 2rem 1rem 1.5rem;
  }

  .translations {
    flex-direction: column;
    gap: 0.35rem;
  }

  .sep {
    display: none;
  }

  .grammar-toolbar {
    flex-direction: column;
    align-items: stretch;
  }

  .grammar-filters {
    flex-direction: column;
    align-items: stretch;
  }

  .grammar-filter select,
  .grammar-filter input {
    width: 100%;
    min-width: 0;
  }
}