@import url('https://fonts.googleapis.com/css2?family=Space+Mono:wght@400;700&family=Syncopate:wght@400;700&display=swap');

/* ============================================================
   CSS 变量 & 重置
   ============================================================ */
:root {
  --c-black: #000000;
  --c-white: #ffffff;
  --c-accent: #000000;
  --c-gray-100: #f5f5f5;
  --c-gray-200: #e8e8e8;
  --c-gray-400: #999999;
  --c-gray-600: #555555;
  --c-bar: #000000;

  --nav-w: 240px;
  --base: 8px;
  --font-sans: 'Space Mono', 'Courier New', monospace;
  --font-display: 'Syncopate', 'Arial Black', sans-serif;

  --radius: 4px;
  --transition: 0.2s ease;
}

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.7;
  color: var(--c-black);
  background: var(--c-white);
  overflow-x: hidden;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--c-black);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

ol, ul {
  list-style: none;
}

/* ============================================================
   布局骨架：左侧固定导航 + 主内容区
   ============================================================ */
.site-wrap {
  display: flex;
  min-height: 100vh;
}

.main-wrap {
  flex: 1;
  margin-left: var(--nav-w);
  min-width: 0;
  display: flex;
  flex-direction: column;
}

/* ============================================================
   侧边导航
   ============================================================ */
.sidenav {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--nav-w);
  height: 100vh;
  background: var(--c-black);
  color: var(--c-white);
  display: flex;
  flex-direction: column;
  z-index: 100;
  overflow-y: auto;
  border-right: 2px solid var(--c-black);
}

.sidenav-brand {
  padding: calc(var(--base) * 3) calc(var(--base) * 2);
  border-bottom: 1px solid rgba(255,255,255,0.15);
}

.brand-link {
  display: flex;
  align-items: center;
  gap: calc(var(--base) * 1);
  color: var(--c-white);
  text-decoration: none;
}

.brand-mark {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.4rem;
  line-height: 1;
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 2px solid var(--c-white);
  flex-shrink: 0;
}

.brand-text {
  font-family: var(--font-display);
  font-size: 0.65rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  line-height: 1.3;
  text-transform: uppercase;
}

.sidenav-search {
  padding: calc(var(--base) * 2);
  border-bottom: 1px solid rgba(255,255,255,0.1);
}

.sidenav-search form {
  display: flex;
  gap: 4px;
}

.sidenav-search input {
  flex: 1;
  background: rgba(255,255,255,0.1);
  border: 1px solid rgba(255,255,255,0.25);
  color: var(--c-white);
  padding: 6px 10px;
  font-family: var(--font-sans);
  font-size: 0.75rem;
  border-radius: var(--radius);
  min-width: 0;
}

.sidenav-search input::placeholder {
  color: rgba(255,255,255,0.4);
}

.sidenav-search button {
  background: var(--c-white);
  border: none;
  color: var(--c-black);
  padding: 6px 10px;
  cursor: pointer;
  font-size: 0.8rem;
  border-radius: var(--radius);
  flex-shrink: 0;
  min-height: 40px;
  min-width: 40px;
}

.sidenav-list {
  padding: calc(var(--base) * 2) 0;
  flex: 1;
}

.sidenav-list li {
  border-bottom: 1px solid rgba(255,255,255,0.06);
}

.sidenav-list li a {
  display: block;
  padding: calc(var(--base) * 1.5) calc(var(--base) * 2);
  color: rgba(255,255,255,0.85);
  font-size: 0.75rem;
  letter-spacing: 0.04em;
  transition: background var(--transition), color var(--transition);
  min-height: 44px;
  display: flex;
  align-items: center;
}

.sidenav-list li a:hover,
.sidenav-list li a[aria-current="page"] {
  background: rgba(255,255,255,0.12);
  color: var(--c-white);
  text-decoration: none;
}

/* 汉堡按钮（移动端） */
.nav-toggle {
  display: none;
  position: fixed;
  top: calc(var(--base) * 2);
  left: calc(var(--base) * 2);
  z-index: 200;
  background: var(--c-black);
  border: 2px solid var(--c-white);
  width: 44px;
  height: 44px;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  cursor: pointer;
  border-radius: var(--radius);
}

.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--c-white);
  transition: transform var(--transition), opacity var(--transition);
}

.nav-toggle[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}
.nav-toggle[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
}
.nav-toggle[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ============================================================
   Hero — 首页
   ============================================================ */
.hero {
  position: relative;
  min-height: 70vh;
  display: flex;
  align-items: flex-end;
  overflow: hidden;
  background: var(--c-black);
}

.hero-media {
  position: absolute;
  inset: 0;
}

.hero-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.45;
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(0,0,0,0.7) 0%, rgba(0,0,0,0.2) 100%);
}

.hero-slant {
  position: absolute;
  bottom: -2px;
  left: 0;
  right: 0;
  height: 80px;
  background: var(--c-white);
  clip-path: polygon(0 100%, 100% 100%, 100% 40%, 0 100%);
}

.hero-body {
  position: relative;
  z-index: 2;
  padding: calc(var(--base) * 8) calc(var(--base) * 6) calc(var(--base) * 12);
  max-width: 720px;
}

.hero-eyebrow {
  display: inline-block;
  font-family: var(--font-display);
  font-size: 0.65rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.7);
  border: 1px solid rgba(255,255,255,0.4);
  padding: 4px 12px;
  margin-bottom: calc(var(--base) * 2);
}

.hero-h1 {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.8rem, 5vw, 3.5rem);
  line-height: 1.1;
  letter-spacing: 0.05em;
  color: var(--c-white);
  margin-bottom: calc(var(--base) * 2);
}

.hero-sub {
  font-size: 1rem;
  color: rgba(255,255,255,0.8);
  line-height: 1.6;
  margin-bottom: calc(var(--base) * 4);
  max-width: 480px;
}

.hero-badge {
  position: absolute;
  top: calc(var(--base) * 8);
  right: calc(var(--base) * 6);
  background: var(--c-white);
  color: var(--c-black);
  font-family: var(--font-display);
  font-size: 0.6rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  padding: 8px 14px;
  text-transform: uppercase;
  border: 2px solid var(--c-black);
}

/* ============================================================
   Hero — 内页变体
   ============================================================ */
.topic-hero,
.tag-hero,
.inner-hero {
  background: var(--c-black);
  color: var(--c-white);
  padding: calc(var(--base) * 8) calc(var(--base) * 6) calc(var(--base) * 10);
  position: relative;
  overflow: hidden;
}

.topic-hero-slant {
  position: absolute;
  bottom: -1px;
  left: 0;
  right: 0;
  height: 60px;
  background: var(--c-white);
  clip-path: polygon(0 100%, 100% 100%, 100% 60%, 0 100%);
}

.inner-hero--sm {
  padding: calc(var(--base) * 6) calc(var(--base) * 6) calc(var(--base) * 8);
}

.topic-hero h1,
.tag-hero h1,
.inner-hero h1 {
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 4vw, 2.8rem);
  font-weight: 700;
  letter-spacing: 0.06em;
  line-height: 1.15;
  margin-bottom: calc(var(--base) * 2);
}

.topic-hero-desc {
  color: rgba(255,255,255,0.75);
  font-size: 1rem;
  max-width: 560px;
}

.eyebrow {
  display: inline-block;
  font-family: var(--font-display);
  font-size: 0.6rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.55);
  border: 1px solid rgba(255,255,255,0.3);
  padding: 3px 10px;
  margin-bottom: calc(var(--base) * 2);
}

/* ============================================================
   面包屑
   ============================================================ */
.breadcrumb {
  padding: calc(var(--base) * 2) calc(var(--base) * 6);
  background: var(--c-gray-100);
  border-bottom: 1px solid var(--c-gray-200);
}

.breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  gap: 0 calc(var(--base) * 1);
  list-style: none;
}

.breadcrumb li {
  font-size: 0.75rem;
  color: var(--c-gray-600);
  letter-spacing: 0.02em;
}

.breadcrumb li + li::before {
  content: '›';
  margin-right: calc(var(--base) * 1);
  color: var(--c-gray-400);
}

.breadcrumb li a {
  color: var(--c-gray-600);
}

.breadcrumb li a:hover {
  color: var(--c-black);
}

/* ============================================================
   内容 + Aside 双栏
   ============================================================ */
.content-aside-wrap {
  display: grid;
  grid-template-columns: 1fr 260px;
  gap: calc(var(--base) * 5);
  padding: calc(var(--base) * 6) calc(var(--base) * 6);
  max-width: 1200px;
  width: 100%;
  flex: 1;
}

/* main > article > section 结构 */
.topic-main,
.article-main,
.tag-main,
.about-main,
.privacy-main {
  min-width: 0;
}

.content-section {
  margin-bottom: calc(var(--base) * 6);
}

.content-inner {
  max-width: 720px;
}

/* ============================================================
   正文内容样式
   ============================================================ */
.art-content h2,
.content-inner h2 {
  font-family: var(--font-display);
  font-size: 1.3rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  margin-top: calc(var(--base) * 5);
  margin-bottom: calc(var(--base) * 2);
  padding-bottom: calc(var(--base) * 1);
  border-bottom: 2px solid var(--c-black);
}

.art-content h3,
.content-inner h3 {
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  margin-top: calc(var(--base) * 4);
  margin-bottom: calc(var(--base) * 1.5);
}

.art-content p,
.content-inner p {
  margin-bottom: calc(var(--base) * 2.5);
  font-size: 1rem;
  line-height: 1.8;
}

.art-content ul,
.art-content ol,
.content-inner ul,
.content-inner ol {
  margin: calc(var(--base) * 2) 0 calc(var(--base) * 3);
  padding-left: calc(var(--base) * 3);
}

.art-content ul { list-style: disc; }
.art-content ol { list-style: decimal; }
.content-inner ul { list-style: disc; }
.content-inner ol { list-style: decimal; }

.art-content li,
.content-inner li {
  margin-bottom: calc(var(--base) * 1);
  font-size: 1rem;
  line-height: 1.7;
}

.art-content a,
.content-inner a {
  color: var(--c-black);
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* ============================================================
   文章页头
   ============================================================ */
.art-header-section {
  margin-bottom: calc(var(--base) * 5);
  padding-bottom: calc(var(--base) * 4);
  border-bottom: 2px solid var(--c-black);
}

.art-meta {
  display: flex;
  flex-wrap: wrap;
  gap: calc(var(--base) * 2);
  align-items: center;
  margin-bottom: calc(var(--base) * 2);
}

.art-date {
  font-size: 0.75rem;
  color: var(--c-gray-600);
  letter-spacing: 0.04em;
}

.art-cat {
  font-family: var(--font-display);
  font-size: 0.65rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  border: 1px solid var(--c-black);
  padding: 3px 10px;
  color: var(--c-black);
}

.art-h1 {
  font-family: var(--font-display);
  font-size: clamp(1.4rem, 3.5vw, 2.4rem);
  font-weight: 700;
  letter-spacing: 0.05em;
  line-height: 1.15;
  margin-bottom: calc(var(--base) * 2);
}

.art-lead {
  font-size: 1.05rem;
  color: var(--c-gray-600);
  line-height: 1.7;
  margin-bottom: calc(var(--base) * 3);
}

.art-hero-wrap {
  margin-top: calc(var(--base) * 3);
  border-radius: var(--radius);
  overflow: hidden;
}

.art-hero-img {
  width: 100%;
  max-height: 420px;
  object-fit: cover;
}

/* ============================================================
   Section ヘッダー
   ============================================================ */
.section-header {
  margin-bottom: calc(var(--base) * 4);
  padding-bottom: calc(var(--base) * 2);
  border-bottom: 2px solid var(--c-black);
}

.section-header h2 {
  font-family: var(--font-display);
  font-size: 1.4rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  margin-bottom: calc(var(--base) * 1);
}

/* h2 + p.subtitle パターン */
h2 + .subtitle,
h2 + p.subhead,
h2 + p.desc,
h2 + p.lead {
  font-size: 0.9rem;
  color: var(--c-gray-600);
  letter-spacing: 0.02em;
  margin-top: calc(var(--base) * -0.5);
  margin-bottom: calc(var(--base) * 2);
  line-height: 1.6;
}

.subtitle {
  font-size: 0.9rem;
  color: var(--c-gray-600);
  letter-spacing: 0.02em;
  line-height: 1.6;
}

/* ============================================================
   首页 Topic カード
   ============================================================ */
.home-content {
  padding: calc(var(--base) * 6) calc(var(--base) * 6) 0;
}

.topics-section {
  padding: calc(var(--base) * 6) calc(var(--base) * 6);
}

.topics-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: calc(var(--base) * 3);
}

.topic-card {
  border: 1px solid var(--c-gray-200);
  border-radius: var(--radius);
  padding: calc(var(--base) * 3);
  position: relative;
  background: var(--c-white);
  transition: border-color var(--transition), transform var(--transition);
}

.topic-card:hover {
  border-color: var(--c-black);
  transform: translateY(-2px);
}

.tc-head {
  display: flex;
  align-items: baseline;
  gap: calc(var(--base) * 1.5);
  margin-bottom: calc(var(--base) * 1.5);
}

.tc-num {
  font-family: var(--font-display);
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--c-gray-400);
  letter-spacing: 0.08em;
  flex-shrink: 0;
}

.tc-head h2 {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  line-height: 1.3;
}

.tc-head h2 a {
  color: var(--c-black);
}

.tc-head h2 + .subtitle,
.topic-card .subtitle {
  font-size: 0.82rem;
  color: var(--c-gray-600);
  line-height: 1.6;
  margin-bottom: calc(var(--base) * 2);
}

.tc-links {
  margin-bottom: calc(var(--base) * 3);
}

.tc-links li {
  font-size: 0.8rem;
  border-top: 1px solid var(--c-gray-100);
  padding: 6px 0;
}

.tc-links li a {
  color: var(--c-gray-600);
  letter-spacing: 0.02em;
}

.tc-links li a:hover {
  color: var(--c-black);
  text-decoration: none;
}

.tc-bar,
.card-bar {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--c-bar);
  border-radius: 0 0 var(--radius) var(--radius);
}

/* ============================================================
   子ページ カード（topic / tag）
   ============================================================ */
.child-list-section,
.tag-list-section {
  margin-top: calc(var(--base) * 4);
}

/* section > article×n 構造 */
.child-list-section,
.tag-list-section {
  display: block;
}

.child-card {
  display: flex;
  flex-direction: column;
  border: 1px solid var(--c-gray-200);
  border-radius: var(--radius);
  overflow: hidden;
  position: relative;
  margin-bottom: calc(var(--base) * 2.5);
  transition: border-color var(--transition);
}

.child-card:hover {
  border-color: var(--c-black);
}

.card-thumb {
  overflow: hidden;
  max-height: 180px;
}

.card-thumb img {
  width: 100%;
  height: 180px;
  object-fit: cover;
  transition: transform 0.4s ease;
}

.child-card:hover .card-thumb img {
  transform: scale(1.03);
}

.card-body {
  padding: calc(var(--base) * 2.5);
  flex: 1;
}

.card-index {
  font-family: var(--font-display);
  font-size: 0.65rem;
  font-weight: 700;
  color: var(--c-gray-400);
  letter-spacing: 0.12em;
  display: block;
  margin-bottom: calc(var(--base) * 1);
}

.card-body h3 {
  font-family: var(--font-display);
  font-size: 0.95rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  line-height: 1.3;
  margin-bottom: calc(var(--base) * 1);
}

.card-body h3 a {
  color: var(--c-black);
}

.card-body h3 a:hover {
  text-decoration: underline;
}

.card-body p {
  font-size: 0.82rem;
  color: var(--c-gray-600);
  line-height: 1.6;
  margin-bottom: calc(var(--base) * 1);
}

.card-date {
  font-size: 0.72rem;
  color: var(--c-gray-400);
  letter-spacing: 0.04em;
}

/* ============================================================
   関連記事
   ============================================================ */
.related-section {
  margin-top: calc(var(--base) * 6);
  padding-top: calc(var(--base) * 4);
  border-top: 2px solid var(--c-black);
}

.related-section h2 {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  margin-bottom: calc(var(--base) * 1);
}

.rel-card {
  border: 1px solid var(--c-gray-200);
  border-radius: var(--radius);
  margin-bottom: calc(var(--base) * 2);
  position: relative;
  transition: border-color var(--transition);
}

.rel-card:hover {
  border-color: var(--c-black);
}

.rel-card a {
  display: flex;
  flex-direction: column;
  padding: calc(var(--base) * 2.5);
  gap: calc(var(--base) * 0.5);
}

.rel-title {
  font-family: var(--font-display);
  font-size: 0.9rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--c-black);
}

.rel-desc {
  font-size: 0.8rem;
  color: var(--c-gray-600);
  line-height: 1.5;
}

/* ============================================================
   Aside サイドバー
   ============================================================ */
.content-aside,
.global-aside {
  min-width: 0;
}

.global-aside {
  position: sticky;
  top: calc(var(--base) * 3);
  align-self: start;
  padding: calc(var(--base) * 6) calc(var(--base) * 3) calc(var(--base) * 6) 0;
  grid-column: 2;
}

.aside-block {
  border: 1px solid var(--c-gray-200);
  border-radius: var(--radius);
  padding: calc(var(--base) * 3);
  margin-bottom: calc(var(--base) * 3);
  position: relative;
}

.aside-block::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 3px;
  height: 100%;
  background: var(--c-black);
  border-radius: var(--radius) 0 0 var(--radius);
}

.aside-block h2 {
  font-family: var(--font-display);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-bottom: calc(var(--base) * 0.5);
}

.aside-block h2 + .subtitle {
  font-size: 0.75rem;
  margin-bottom: calc(var(--base) * 2);
}

.aside-links {
  list-style: none;
}

.aside-links li {
  border-top: 1px solid var(--c-gray-100);
  padding: 6px 0;
}

.aside-links li:first-child {
  border-top: none;
}

.aside-links li a {
  font-size: 0.8rem;
  color: var(--c-gray-600);
  letter-spacing: 0.02em;
  display: block;
  min-height: 36px;
  display: flex;
  align-items: center;
}

.aside-links li a:hover {
  color: var(--c-black);
  text-decoration: none;
}

.tag-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: calc(var(--base) * 1);
  margin-top: calc(var(--base) * 1.5);
}

.tag-link {
  display: inline-flex;
  align-items: center;
  font-family: var(--font-display);
  font-size: 0.65rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  border: 1px solid var(--c-black);
  padding: 5px 12px;
  min-height: 32px;
  transition: background var(--transition), color var(--transition);
  border-radius: var(--radius);
}

.tag-link:hover {
  background: var(--c-black);
  color: var(--c-white);
  text-decoration: none;
}

/* ============================================================
   About Stats
   ============================================================ */
.about-stats {
  margin-top: calc(var(--base) * 6);
  padding-top: calc(var(--base) * 4);
  border-top: 2px solid var(--c-black);
}

.about-stats h2 {
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  margin-bottom: calc(var(--base) * 1);
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: calc(var(--base) * 2);
  margin-top: calc(var(--base) * 3);
}

.stat-item {
  border: 1px solid var(--c-gray-200);
  border-radius: var(--radius);
  padding: calc(var(--base) * 3);
  text-align: center;
  position: relative;
}

.stat-item::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--c-black);
  border-radius: 0 0 var(--radius) var(--radius);
}

.stat-num {
  display: block;
  font-family: var(--font-display);
  font-size: 1.8rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  line-height: 1;
  margin-bottom: calc(var(--base) * 1);
}

.stat-label {
  font-size: 0.75rem;
  color: var(--c-gray-600);
  letter-spacing: 0.04em;
}

/* ============================================================
   Privacy 注意事項
   ============================================================ */
.privacy-note {
  margin-top: calc(var(--base) * 6);
  padding: calc(var(--base) * 4);
  border: 1px solid var(--c-gray-200);
  border-radius: var(--radius);
  border-left: 4px solid var(--c-black);
}

.privacy-note h2 {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  margin-bottom: calc(var(--base) * 1);
}

.notice-list {
  margin-top: calc(var(--base) * 2);
  padding-left: calc(var(--base) * 2);
  list-style: disc;
}

.notice-list li {
  font-size: 0.9rem;
  line-height: 1.7;
  margin-bottom: calc(var(--base) * 1);
}

/* ============================================================
   ボタン
   ============================================================ */
.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-display);
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  background: var(--c-black);
  color: var(--c-white);
  padding: 14px 28px;
  min-height: 48px;
  border-radius: var(--radius);
  transition: background var(--transition), transform var(--transition);
  text-decoration: none;
}

.btn-primary:hover {
  background: #333;
  text-decoration: none;
  transform: translateY(-1px);
}

.btn-outline {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-display);
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  background: transparent;
  color: var(--c-black);
  border: 2px solid var(--c-black);
  padding: 12px 24px;
  min-height: 44px;
  border-radius: var(--radius);
  transition: background var(--transition), color var(--transition);
  text-decoration: none;
}

.btn-outline:hover {
  background: var(--c-black);
  color: var(--c-white);
  text-decoration: none;
}

/* ============================================================
   フッター
   ============================================================ */
.site-footer {
  background: var(--c-black);
  color: var(--c-white);
  margin-top: auto;
}

.footer-cta {
  padding: calc(var(--base) * 8) calc(var(--base) * 6);
  border-bottom: 1px solid rgba(255,255,255,0.12);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: calc(var(--base) * 4);
  flex-wrap: wrap;
}

.footer-cta p {
  font-size: 1rem;
  color: rgba(255,255,255,0.8);
  line-height: 1.5;
}

.footer-cta .btn-primary {
  background: var(--c-white);
  color: var(--c-black);
  flex-shrink: 0;
}

.footer-cta .btn-primary:hover {
  background: var(--c-gray-200);
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: calc(var(--base) * 4);
  padding: calc(var(--base) * 6);
  border-bottom: 1px solid rgba(255,255,255,0.1);
}

.footer-col {
  display: flex;
  flex-direction: column;
  gap: calc(var(--base) * 1.5);
}

.footer-col strong {
  font-family: var(--font-display);
  font-size: 0.65rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.5);
  margin-bottom: calc(var(--base) * 0.5);
}

.footer-col a {
  font-size: 0.82rem;
  color: rgba(255,255,255,0.75);
  letter-spacing: 0.02em;
  min-height: 28px;
  display: flex;
  align-items: center;
  transition: color var(--transition);
}

.footer-col a:hover {
  color: var(--c-white);
  text-decoration: none;
}

.footer-nav {
  padding: calc(var(--base) * 3) calc(var(--base) * 6);
  border-bottom: 1px solid rgba(255,255,255,0.08);
}

.footer-nav ol {
  display: flex;
  flex-wrap: wrap;
  gap: calc(var(--base) * 3);
  list-style: none;
}

.footer-nav ol li a {
  font-size: 0.75rem;
  color: rgba(255,255,255,0.5);
  letter-spacing: 0.04em;
  min-height: 40px;
  display: inline-flex;
  align-items: center;
  transition: color var(--transition);
}

.footer-nav ol li a:hover {
  color: var(--c-white);
  text-decoration: none;
}

.footer-copy {
  padding: calc(var(--base) * 3) calc(var(--base) * 6);
  text-align: center;
}

.footer-copy p {
  font-size: 0.72rem;
  color: rgba(255,255,255,0.4);
  letter-spacing: 0.04em;
  line-height: 1.6;
}

/* ============================================================
   Scroll Reveal アニメ
   ============================================================ */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

@media (prefers-reduced-motion: reduce) {
  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
}

/* ============================================================
   レスポンシブ：タブレット
   ============================================================ */
@media (max-width: 1024px) {
  :root {
    --nav-w: 200px;
  }

  .topics-grid {
    grid-template-columns: 1fr;
  }

  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* ============================================================
   レスポンシブ：モバイル
   ============================================================ */
@media (max-width: 768px) {
  :root {
    --nav-w: 0px;
  }

  .sidenav {
    transform: translateX(-100%);
    transition: transform 0.3s ease;
    width: 280px;
  }

  .sidenav.is-open {
    transform: translateX(0);
  }

  .nav-toggle {
    display: flex;
  }

  .main-wrap {
    margin-left: 0;
    padding-top: 60px;
  }

  .content-aside-wrap {
    grid-template-columns: 1fr;
    padding: calc(var(--base) * 4) calc(var(--base) * 3);
    gap: calc(var(--base) * 4);
  }

  .content-aside {
    order: -1;
  }

  .global-aside {
    padding: calc(var(--base) * 4) calc(var(--base) * 3) 0;
    position: static;
  }

  .hero-body {
    padding: calc(var(--base) * 6) calc(var(--base) * 3) calc(var(--base) * 10);
  }

  .hero-badge {
    top: calc(var(--base) * 3);
    right: calc(var(--base) * 3);
    font-size: 0.55rem;
    padding: 6px 10px;
  }

  .hero-slant {
    height: 50px;
  }

  .topic-hero,
  .tag-hero,
  .inner-hero {
    padding: calc(var(--base) * 5) calc(var(--base) * 3) calc(var(--base) * 8);
  }

  .home-content,
  .topics-section {
    padding: calc(var(--base) * 4) calc(var(--base) * 3);
  }

  .footer-cta {
    padding: calc(var(--base) * 5) calc(var(--base) * 3);
    flex-direction: column;
    align-items: flex-start;
    gap: calc(var(--base) * 3);
  }

  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
    padding: calc(var(--base) * 4) calc(var(--base) * 3);
    gap: calc(var(--base) * 3);
  }

  .footer-nav,
  .footer-copy {
    padding-left: calc(var(--base) * 3);
    padding-right: calc(var(--base) * 3);
  }

  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: calc(var(--base) * 2);
  }

  .stat-num {
    font-size: 1.4rem;
  }

  .breadcrumb {
    padding: calc(var(--base) * 2) calc(var(--base) * 3);
  }

  .art-meta {
    gap: calc(var(--base) * 1.5);
  }
}

@media (max-width: 480px) {
  .footer-grid {
    grid-template-columns: 1fr;
  }

  .topics-grid {
    grid-template-columns: 1fr;
  }

  .hero-h1 {
    font-size: 1.6rem;
  }
}