:root {
  --c-bg: #f3f3f1;
  --c-surface: #ffffff;
  --c-text: #191919;
  --c-muted: #666666;
  --c-border: #d8d8d4;
  --c-accent: #191919;
  --c-accent-soft: #eeeeeb;
  --c-control-text: #444444;
  --c-control-active: #666666;
  --c-control-fill: #e6e6e2;
  --c-warning: #3f3f3f;
  --c-warning-soft: #f4f4f2;
  --radius: 0;
  --container: 1360px;
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.85rem;
  --space-xl: 3.25rem;
  --space-2xl: 5rem;
  --font-body: "Shippori Mincho", "Hiragino Mincho ProN", "Yu Mincho", "YuMincho", serif;
}

* {
  box-sizing: border-box;
}

[hidden] {
  display: none !important;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--c-bg);
  color: var(--c-text);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.7;
  letter-spacing: 0.02em;
}

a {
  color: inherit;
  text-decoration: none;
}

button,
input {
  font: inherit;
}

button {
  min-height: 44px;
  cursor: pointer;
}

:focus-visible {
  outline: 2px solid rgba(25, 25, 25, 0.4);
  outline-offset: 3px;
}

.skip-link {
  position: absolute;
  left: 1rem;
  top: 1rem;
  z-index: 10;
  transform: translateY(-140%);
  border-radius: var(--radius);
  background: var(--c-text);
  color: #fff;
  padding: 0.75rem 1rem;
}

.skip-link:focus {
  transform: translateY(0);
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 5;
  background: var(--c-bg);
  background-color: var(--c-bg);
  border-bottom: 1px solid var(--c-border);
  opacity: 1;
  transition: transform 180ms ease;
}

.top-nav {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  max-width: var(--container);
  margin: 0 auto;
  padding: 0.72rem clamp(0.9rem, 2.5vw, 1.75rem);
}

.header-logo {
  display: inline-flex;
  align-items: center;
  flex: 0 0 auto;
}

.header-logo img {
  display: block;
  height: 28px;
  width: auto;
}

.header-divider {
  width: 1px;
  height: 24px;
  background: var(--c-border);
  flex: 0 0 auto;
}

.brand {
  font-weight: 600;
  line-height: 1.3;
  margin-right: auto;
  white-space: nowrap;
}

.header-nav {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  margin-left: auto;
  color: var(--c-muted);
  font-size: 0.88rem;
}

.header-nav a {
  color: var(--c-muted);
}

.header-nav a:hover,
.header-nav-cta {
  color: var(--c-text);
}

main {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 clamp(1rem, 2.5vw, 1.75rem) clamp(1rem, 2.5vw, 1.75rem);
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  max-width: 760px;
  margin-bottom: var(--space-md);
  font-size: clamp(2rem, 5vw, 4.3rem);
  line-height: 1.16;
  letter-spacing: 0;
}

h2 {
  margin-bottom: var(--space-xs);
  font-size: clamp(1.35rem, 2vw, 2rem);
  line-height: 1.35;
  letter-spacing: 0;
}

h3 {
  margin-bottom: var(--space-sm);
  font-size: 1rem;
  line-height: 1.45;
  letter-spacing: 0;
}

.lead {
  max-width: 620px;
  margin-bottom: 0;
  color: var(--c-muted);
  font-size: clamp(1rem, 1.4vw, 1.18rem);
}

.search-panel,
.word-card,
.title-card,
 .tab-button {
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  background: var(--c-surface);
}

.search-panel {
  flex: 0 1 470px;
  margin-left: auto;
  padding: var(--space-md);
}

.search-panel label {
  display: block;
  margin-bottom: var(--space-sm);
  color: var(--c-muted);
  font-size: 0.9rem;
  font-weight: 600;
}

.search-row {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-sm);
}

.search-row input {
  min-height: 48px;
  width: 100%;
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  padding: 0.75rem 0.9rem;
  color: var(--c-text);
}

.search-row button,
.filter-button {
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  background: var(--c-control-fill);
  color: var(--c-control-text);
  font-weight: 500;
}

.search-row button {
  padding: 0.75rem 1rem;
}

.search-row button:hover,
.filter-button:hover {
  border-color: var(--c-control-active);
  color: var(--c-text);
}

.dictionary-section {
  padding: var(--space-md) 0 calc(var(--space-2xl) / 2);
}

.dictionary-controls {
  position: sticky;
  top: 44px;
  z-index: 4;
  background: var(--c-bg);
  background-color: var(--c-bg);
  margin: 0 calc(clamp(1rem, 2.5vw, 1.75rem) * -1) var(--space-md);
  padding: var(--space-md) clamp(1rem, 2.5vw, 1.75rem);
  opacity: 1;
  transition: transform 180ms ease;
}

body.is-scrolling-down .site-header {
  transform: translateY(-100%);
}

body.is-scrolling-down .dictionary-controls {
  transform: translateY(calc(-100% - 44px));
}

body.is-scrolling-up .site-header,
body.is-scrolling-up .dictionary-controls {
  transform: translateY(0);
  opacity: 1;
}

.filter-section {
  padding: var(--space-sm) 0 0;
}

.section-heading {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
  margin-bottom: var(--space-md);
}

.section-heading p {
  margin-bottom: 0;
  color: var(--c-muted);
}

.with-count {
  gap: var(--space-md);
}

.tabs-row {
  display: flex;
  align-items: center;
  justify-content: flex-start;
  gap: var(--space-md);
  margin-bottom: var(--space-sm);
}

.tabs {
  display: flex;
  gap: var(--space-sm);
}

.tab-button {
  min-width: 120px;
  min-height: 38px;
  padding: 0.42rem 0.9rem;
  color: var(--c-control-text);
  font-weight: 500;
}

.tab-button.is-active {
  border-color: var(--c-control-active);
  background: var(--c-control-active);
  color: #fff;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

.filters {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

.filter-toggle {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  min-height: 36px;
  border: 1px solid var(--c-border);
  background: var(--c-control-fill);
  color: var(--c-control-text);
  padding: 0.38rem 0.76rem;
  font-weight: 500;
}

.filter-toggle:hover {
  border-color: var(--c-control-active);
  color: var(--c-text);
}

.filter-toggle__icon {
  font-size: 0.78rem;
  line-height: 1;
}

.filter-toggle[aria-expanded="true"] .filter-toggle__icon {
  transform: rotate(180deg);
}

.controls-row {
  display: flex;
  align-items: flex-start;
  gap: var(--space-lg);
  margin-top: var(--space-sm);
}

.word-filters,
.title-filters {
  flex: 1 1 auto;
}

.filter-button {
  min-height: 36px;
  padding: 0.38rem 0.76rem;
}

.filter-button.is-active,
.title-filter-button.is-active {
  border-color: var(--c-control-active);
  background: var(--c-control-active);
  color: #fff;
}

.title-filter-button {
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  background: var(--c-control-fill);
  color: var(--c-control-text);
  font-weight: 500;
  min-height: 36px;
  padding: 0.38rem 0.76rem;
}

.title-filter-button:hover {
  border-color: var(--c-control-active);
  color: var(--c-text);
}

.title-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--space-lg);
}

.word-grid {
  display: grid;
  gap: var(--space-xl);
}

.word-category {
  display: grid;
  gap: var(--space-md);
}

.word-category__header {
  display: grid;
  gap: var(--space-sm);
  background: transparent;
  padding: var(--space-sm) 0 0;
}

.word-category__header h3 {
  margin: 0;
  padding-bottom: var(--space-sm);
  border-bottom: 1px solid var(--c-border);
  font-size: clamp(1.25rem, 1.8vw, 1.75rem);
  font-weight: 600;
}

.category-meta {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: var(--space-md);
  margin: 0;
}

.category-meta dt {
  color: var(--c-muted);
  font-size: 0.78rem;
  font-weight: 600;
}

.category-meta dd {
  margin: 0.18rem 0 0;
}

.category-word-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: var(--space-md);
}

@media (min-width: 980px) {
  .category-word-grid,
  .title-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.word-card,
.title-card {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
  padding: var(--space-xl);
}

.word-card {
  min-height: 190px;
  padding: var(--space-lg);
}

.title-card {
  min-height: 250px;
}

.title-card__top {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: var(--space-md);
}

.word-card__word,
.title-card__title {
  margin: 0;
  font-size: clamp(1.45rem, 2vw, 2rem);
  font-weight: 600;
  line-height: 1.25;
  letter-spacing: 0;
}

.title-card__title {
  font-size: clamp(1.1rem, 1.4vw, 1.45rem);
  line-height: 1.55;
}

.meta-list {
  display: grid;
  gap: var(--space-sm);
  margin: 0;
}

.meta-row {
  display: grid;
  gap: 0.15rem;
}

.meta-row dt {
  color: var(--c-muted);
  font-size: 0.78rem;
  font-weight: 600;
}

.meta-row dd {
  margin: 0;
}

.example {
  margin: auto 0 0;
  border-left: 3px solid var(--c-accent);
  padding-left: var(--space-md);
  color: var(--c-text);
  font-weight: 600;
}

.reason {
  margin: 0;
  color: var(--c-muted);
}

.caution {
  border-radius: var(--radius);
  background: var(--c-warning-soft);
  color: var(--c-warning);
  padding: 0.9rem;
  font-size: 0.88rem;
}

.empty-state {
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  background: var(--c-surface);
  padding: var(--space-lg);
  color: var(--c-muted);
}

.site-footer {
  max-width: var(--container);
  margin: 0 auto;
  padding: var(--space-xl) clamp(1rem, 4vw, 2rem);
  color: var(--c-muted);
}

.site-footer p {
  margin-bottom: 0;
}

@media (min-width: 680px) {
  .search-row {
    grid-template-columns: 1fr auto;
  }

  .section-heading,
  .with-count {
    flex-direction: row;
    align-items: end;
    justify-content: space-between;
  }

  .usage-list {
    grid-template-columns: repeat(3, 1fr);
  }
}

@media (max-width: 620px) {
  .top-nav {
    align-items: flex-start;
    flex-direction: column;
  }

  .nav-links {
    width: 100%;
    overflow-x: auto;
    padding-bottom: 0.1rem;
    white-space: nowrap;
  }

  .word-card {
    min-height: auto;
  }

  .category-meta {
    grid-template-columns: 1fr;
  }

  .tabs-row {
    align-items: stretch;
    flex-direction: column;
  }

  .controls-row {
    flex-direction: column;
  }

  .search-panel {
    flex: none;
    width: 100%;
    margin-left: 0;
  }

  .tabs {
    display: grid;
    grid-template-columns: 1fr 1fr;
  }
}

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