/* ===== Reset & Base ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  /* Typography */
  --font-sans: 'Noto Serif SC', 'Hiragino Mincho ProN', 'Yu Mincho', 'Source Han Serif SC', Georgia, serif;
  --font-ui: system-ui, -apple-system, 'Segoe UI', Helvetica, Arial, sans-serif;
  --font-mono: 'JetBrains Mono', 'Courier New', monospace;

  /* Color palette — warm jade / cream TCM health theme */
  --color-bg: #fdfaf5;
  --color-bg-subtle: #f5f0e7;
  --color-surface: #ffffff;
  --color-text: #1c1a16;
  --color-text-secondary: #3d3828;
  --color-muted: #7c7260;
  --color-border: #e2d9c8;
  --color-border-strong: #cdc3b0;
  --color-accent: #2d6b4f;
  --color-accent-hover: #1e4d37;
  --color-accent-light: #eef6f1;
  --color-accent-subtle: #d4ebe0;
  --color-amber: #c47c2e;
  --color-amber-light: #fdf3e3;
  --color-tag-bg: #ede8df;
  --color-tag-text: #3d3828;
  --color-code-bg: #faf7f0;
  --color-focus-ring: rgba(45, 107, 79, 0.15);

  /* Header */
  --color-header-bg: #1a3a28;
  --color-header-text: #f0ebe0;
  --color-header-muted: rgba(240,235,224,0.65);
  --color-header-border: rgba(255,255,255,0.10);
  --color-header-tag-bg: rgba(255,255,255,0.12);
  --color-header-tag-hover: rgba(255,255,255,0.22);

  /* Shadows */
  --shadow-xs: 0 1px 2px rgba(0,0,0,0.06);
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.10), 0 1px 2px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.10), 0 2px 4px rgba(0,0,0,0.06);

  /* Layout */
  --max-width: 920px;
  --nav-height: 3.75rem;

  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3.5rem;

  /* Radius */
  --radius-sm: 0.25rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
}

/* ===== Mobile-first Base ===== */
html {
  font-size: 100%;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  font-size: 1rem;
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.85;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* ===== Typography ===== */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-sans);
  font-weight: 700;
  line-height: 1.35;
  margin-bottom: var(--spacing-md);
  color: var(--color-text);
  letter-spacing: 0.02em;
}
h1 { font-size: 1.75rem; }
h2 { font-size: 1.25rem; margin-top: var(--spacing-lg); }
h3 { font-size: 1.0625rem; margin-top: var(--spacing-md); }
h4, h5, h6 { font-size: 1rem; margin-top: var(--spacing-md); }

@media (min-width: 640px) {
  body { font-size: 1.0625rem; }
  h1 { font-size: 2.25rem; }
  h2 { font-size: 1.5rem; margin-top: var(--spacing-xl); }
  h3 { font-size: 1.25rem; margin-top: var(--spacing-lg); }
}

p { margin-bottom: var(--spacing-md); }

a { color: var(--color-accent); text-decoration: none; }
a:hover { color: var(--color-accent-hover); text-decoration: underline; }

ul, ol { margin-left: var(--spacing-lg); margin-bottom: var(--spacing-md); }
li { margin-bottom: var(--spacing-xs); }

blockquote {
  border-left: 3px solid var(--color-accent);
  padding: var(--spacing-sm) var(--spacing-md);
  margin: var(--spacing-lg) 0;
  background: var(--color-accent-light);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--color-text-secondary);
  font-style: italic;
  font-size: 0.9375rem;
}

code {
  font-family: var(--font-mono);
  background: var(--color-code-bg);
  border: 1px solid var(--color-border);
  padding: 0.1em 0.35em;
  border-radius: var(--radius-sm);
  font-size: 0.875em;
  color: var(--color-text);
  word-break: break-word;
}

pre {
  background: #1a2f20;
  border: 1px solid #2d4a38;
  border-radius: var(--radius-md);
  padding: var(--spacing-md);
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  margin-bottom: var(--spacing-lg);
  font-size: 0.8125rem;
  color: #d4e8d8;
}
pre code { background: none; border: none; padding: 0; font-size: inherit; word-break: normal; color: inherit; }

hr { border: none; border-top: 1px solid var(--color-border); margin: var(--spacing-xl) 0; }

/* Responsive tables */
table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: var(--spacing-lg);
  display: block;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
}
th, td {
  padding: var(--spacing-sm) var(--spacing-md);
  border: 1px solid var(--color-border);
  text-align: left;
  font-size: 0.875rem;
  white-space: nowrap;
}
th { background: var(--color-bg-subtle); font-weight: 600; }

@media (min-width: 640px) {
  table { display: table; }
  th, td { white-space: normal; font-size: 0.9375rem; }
}

img { max-width: 100%; height: auto; border-radius: var(--radius-md); }

/* ===== Layout ===== */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--spacing-md);
  flex: 1;
}

@media (min-width: 640px) {
  .container { padding: var(--spacing-lg); }
}

/* ===== Header & Nav — deep jade dark header ===== */
.site-header {
  background: var(--color-header-bg);
  border-bottom: 1px solid var(--color-header-border);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 8px rgba(0,0,0,0.18);
}

.nav {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  padding: 0 var(--spacing-md);
  min-height: var(--nav-height);
}

/* Logo mark: 元 icon + brand name */
.site-title {
  font-family: var(--font-ui);
  font-size: 0.9375rem;
  font-weight: 700;
  color: var(--color-header-text);
  text-decoration: none;
  flex-shrink: 0;
  padding: 0.625rem 0;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  letter-spacing: 0.02em;
  transition: opacity 0.2s;
}
.site-title::before {
  content: '元';
  font-family: var(--font-sans);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1.75rem;
  height: 1.75rem;
  background: var(--color-accent);
  color: #fff;
  border-radius: var(--radius-sm);
  font-size: 0.9375rem;
  flex-shrink: 0;
  line-height: 1;
  box-shadow: 0 1px 3px rgba(0,0,0,0.25);
}
.site-title:hover { opacity: 0.85; text-decoration: none; color: var(--color-header-text); }

/* Hamburger toggle */
.nav-toggle {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  cursor: pointer;
  padding: 0.5rem;
  margin-left: auto;
  background: none;
  border: 1px solid var(--color-header-border);
  border-radius: var(--radius-sm);
  color: var(--color-header-text);
  line-height: 1;
  transition: border-color 0.2s, background 0.2s;
}
.nav-toggle:hover { border-color: rgba(255,255,255,0.35); background: rgba(255,255,255,0.08); }

.nav-toggle span {
  display: block;
  width: 18px;
  height: 2px;
  background: currentColor;
  border-radius: 2px;
  transition: transform 0.25s, opacity 0.25s;
}
.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; transform: scaleX(0); }
.nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* Collapsible drawer */
.nav-collapse {
  display: none;
  width: 100%;
  flex-direction: column;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) 0 var(--spacing-md);
  border-top: 1px solid var(--color-header-border);
}
.nav-collapse.is-open { display: flex; }

.nav-links {
  display: flex;
  list-style: none;
  gap: var(--spacing-xs) var(--spacing-sm);
  margin: 0;
  flex-wrap: wrap;
  align-items: center;
}

.nav-links a {
  font-family: var(--font-ui);
  font-size: 0.875rem;
  color: var(--color-header-muted);
  transition: color 0.2s;
  text-decoration: none;
  font-weight: 500;
}
.nav-links a:hover { color: var(--color-header-text); text-decoration: none; }

/* Tag pills in nav */
.nav-tag-group {
  display: flex;
  gap: var(--spacing-xs);
  align-items: center;
  flex-wrap: wrap;
}
.nav-tag {
  font-family: var(--font-ui);
  font-size: 0.7rem;
  padding: 0.15em 0.6em;
  background: var(--color-header-tag-bg);
  color: var(--color-header-text);
  border-color: transparent;
  transition: background 0.2s, color 0.2s;
}
.nav-tag:hover { background: var(--color-header-tag-hover); color: #fff; border-color: transparent; }

/* Search */
.nav-search { width: 100%; }

.search-form {
  display: flex;
  align-items: center;
  border: 1px solid rgba(255,255,255,0.2);
  border-radius: var(--radius-md);
  overflow: hidden;
  background: rgba(255,255,255,0.08);
  width: 100%;
  transition: border-color 0.2s, box-shadow 0.2s;
}
.search-form:focus-within {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(45,107,79,0.25);
  background: rgba(255,255,255,0.14);
}

.search-input {
  flex: 1;
  border: none;
  background: transparent;
  font-family: var(--font-ui);
  font-size: 0.9375rem;
  padding: 0.5em 0.75em;
  color: var(--color-header-text);
  outline: none;
  min-width: 0;
}
.search-input::placeholder { color: var(--color-header-muted); }

.search-btn {
  background: transparent;
  border: none;
  cursor: pointer;
  padding: 0.5em 0.75em;
  color: var(--color-header-muted);
  display: flex;
  align-items: center;
  transition: color 0.2s;
  flex-shrink: 0;
}
.search-btn:hover, .search-btn:active { color: var(--color-header-text); }

/* Desktop nav */
@media (min-width: 640px) {
  .nav {
    flex-wrap: nowrap;
    padding: 0 var(--spacing-lg);
    min-height: 0;
    height: var(--nav-height);
    gap: var(--spacing-md);
  }
  .site-title { padding: 0; }
  .nav-toggle { display: none; }

  .nav-collapse {
    display: flex !important;
    flex-direction: row;
    align-items: center;
    flex: 1;
    width: auto;
    border-top: none;
    padding: 0;
    gap: var(--spacing-md);
  }

  .nav-links { flex-wrap: nowrap; gap: var(--spacing-md); }
  .nav-search { width: auto; margin-left: auto; flex-shrink: 0; }
  .search-form { width: auto; border-radius: var(--radius-md); }
  .search-input { width: 160px; font-size: 0.8125rem; padding: 0.3em 0.6em; }
  .search-btn { padding: 0.35em 0.5em; }
}

@media (min-width: 860px) {
  .search-input { width: 220px; }
}

/* ===== Footer ===== */
.site-footer {
  background: var(--color-header-bg);
  border-top: 1px solid var(--color-header-border);
  padding: var(--spacing-lg);
  text-align: center;
  font-family: var(--font-ui);
  font-size: 0.8125rem;
  color: var(--color-header-muted);
}
.site-footer a { color: var(--color-header-muted); transition: color 0.2s; }
.site-footer a:hover { color: var(--color-header-text); text-decoration: none; }
.footer-powered { margin-top: var(--spacing-xs); font-size: 0.75rem; }
.support-link { margin-top: var(--spacing-xs); }
.support-link a { color: var(--color-amber); }

/* ===== Home Page ===== */
.home-hero {
  padding: var(--spacing-lg) 0 var(--spacing-md);
  border-bottom: 1px solid var(--color-border);
  margin-bottom: var(--spacing-lg);
}
@media (min-width: 640px) {
  .home-hero { padding: 3.5rem 0 var(--spacing-lg); }
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
  background: var(--color-accent-light);
  color: var(--color-accent);
  border: 1px solid var(--color-accent-subtle);
  border-radius: 999px;
  font-family: var(--font-ui);
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 0.25em 0.875em;
  margin-bottom: var(--spacing-md);
}

.home-hero h1 {
  font-size: 2rem;
  letter-spacing: 0.04em;
  color: var(--color-text);
  line-height: 1.25;
}
@media (min-width: 640px) {
  .home-hero h1 { font-size: 3rem; }
}

.hero-ja {
  font-size: 1rem;
  color: var(--color-muted);
  margin-top: 0.25rem;
  letter-spacing: 0.05em;
  font-style: italic;
}
@media (min-width: 640px) {
  .hero-ja { font-size: 1.25rem; }
}

.home-tagline {
  font-size: 0.9375rem;
  color: var(--color-text-secondary);
  max-width: 560px;
  margin-top: var(--spacing-sm);
  line-height: 1.75;
}
@media (min-width: 640px) {
  .home-tagline { font-size: 1.0625rem; }
}

.tagline-en {
  font-size: 0.8125rem;
  color: var(--color-muted);
  margin-top: var(--spacing-xs);
  font-style: italic;
}

/* ===== Recent Notes section ===== */
.recent-posts { margin-top: var(--spacing-lg); }
.recent-posts h2, .sections-nav h2 { margin-top: 0; }

/* ===== Section Cards ===== */
.sections-nav {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-sm);
  margin-top: var(--spacing-lg);
  padding-top: var(--spacing-lg);
  border-top: 1px solid var(--color-border);
}
@media (min-width: 640px) {
  .sections-nav {
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-xl);
    padding-top: var(--spacing-xl);
  }
}

.section-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-md);
  box-shadow: var(--shadow-xs);
  transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
}
.section-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-sm);
  border-color: var(--color-accent);
}
.section-card a { color: var(--color-text); display: block; text-decoration: none; }
.section-card a:hover { text-decoration: none; color: var(--color-text); }
.card-icon { font-size: 1.5rem; margin-bottom: var(--spacing-xs); display: block; line-height: 1; }
.section-card h3 { margin-top: 0; margin-bottom: 0.25rem; font-size: 1rem; letter-spacing: 0.03em; }
.card-label-ja { font-size: 0.7rem; color: var(--color-muted); display: block; margin-bottom: var(--spacing-xs); }
.section-card p { color: var(--color-muted); font-size: 0.8125rem; margin: 0; line-height: 1.5; }

.view-all {
  display: inline-flex;
  align-items: center;
  gap: 0.3em;
  margin-top: var(--spacing-md);
  font-family: var(--font-ui);
  font-size: 0.875rem;
  color: var(--color-accent);
  font-weight: 500;
  transition: gap 0.2s;
}
.view-all:hover { gap: 0.5em; text-decoration: none; }

/* ===== Post List ===== */
.post-list { list-style: none; margin: 0; padding: 0; }
.post-item { padding: var(--spacing-md) 0; border-bottom: 1px solid var(--color-border); }
.post-date { font-family: var(--font-mono); font-size: 0.75rem; color: var(--color-muted); display: block; margin-bottom: 0.2rem; }
.post-item > a {
  font-weight: 600;
  font-size: 1rem;
  display: block;
  color: var(--color-text);
  letter-spacing: 0.02em;
  transition: color 0.15s;
}
.post-item > a:hover { color: var(--color-accent); text-decoration: none; }
.post-tags { margin-top: var(--spacing-xs); }

@media (min-width: 640px) {
  .post-item {
    display: grid;
    grid-template-columns: auto 1fr;
    grid-template-rows: auto auto;
    gap: 0 var(--spacing-md);
    align-items: start;
  }
  .post-date { font-size: 0.8rem; white-space: nowrap; grid-row: 1; display: inline; margin-bottom: 0; }
  .post-item > a { font-size: 1.0625rem; display: inline; grid-row: 1; }
  .post-tags { grid-column: 2; grid-row: 2; }
}

/* ===== Tags ===== */
.tag {
  display: inline-block;
  background: var(--color-tag-bg);
  color: var(--color-tag-text);
  padding: 0.15em 0.6em;
  border-radius: var(--radius-sm);
  font-family: var(--font-ui);
  font-size: 0.7rem;
  font-weight: 500;
  margin-right: var(--spacing-xs);
  margin-bottom: var(--spacing-xs);
  text-decoration: none;
  border: 1px solid var(--color-border);
  transition: background 0.15s, color 0.15s, border-color 0.15s;
}
.tag:hover { background: var(--color-accent); color: #fff; border-color: var(--color-accent); text-decoration: none; }
.tag-lg { font-size: 0.875rem; padding: 0.2em 0.8em; margin: var(--spacing-xs); }
.tag-count { color: var(--color-muted); }
.tag-cloud { display: flex; flex-wrap: wrap; gap: var(--spacing-xs); padding: var(--spacing-md) 0; }

/* ===== Page Header ===== */
.page-header {
  padding: var(--spacing-lg) 0;
  border-bottom: 1px solid var(--color-border);
  margin-bottom: var(--spacing-lg);
}
@media (min-width: 640px) {
  .page-header { padding: var(--spacing-xl) 0 var(--spacing-lg); }
}
.page-header h1 { margin-bottom: 0; }
.page-desc { color: var(--color-muted); margin-top: var(--spacing-sm); font-size: 0.9375rem; }

/* ===== Article / Single Post ===== */
.post-header {
  padding: var(--spacing-lg) 0;
  border-bottom: 1px solid var(--color-border);
  margin-bottom: var(--spacing-lg);
}
@media (min-width: 640px) {
  .post-header { padding: var(--spacing-xl) 0 var(--spacing-lg); margin-bottom: var(--spacing-xl); }
}

.post-title-ja {
  font-size: 1rem;
  color: var(--color-muted);
  font-style: italic;
  margin-top: 0.25rem;
  margin-bottom: 0;
  letter-spacing: 0.04em;
}
.post-title-en {
  font-size: 0.875rem;
  color: var(--color-muted);
  margin-top: 0.1rem;
  margin-bottom: 0;
  font-style: italic;
}

.post-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--spacing-sm);
  margin-top: var(--spacing-sm);
  color: var(--color-muted);
  font-size: 0.8125rem;
  font-family: var(--font-mono);
}
.post-content { max-width: 72ch; }
.post-content h2 { border-bottom: 1px solid var(--color-border); padding-bottom: var(--spacing-sm); }

/* ===== Diagrams / Excalidraw ===== */
.diagram, .excalidraw-diagram {
  margin: var(--spacing-lg) 0;
  text-align: center;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}
.diagram img, .excalidraw-diagram .excalidraw-img {
  border: 1px solid var(--color-border);
  max-width: 100%;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
}
.diagram figcaption, .excalidraw-diagram figcaption {
  font-family: var(--font-ui);
  font-size: 0.75rem;
  color: var(--color-muted);
  margin-top: var(--spacing-xs);
}
.excalidraw-frame {
  width: 100%;
  min-height: 480px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
}

/* ===== Callout boxes ===== */
.callout {
  padding: var(--spacing-md);
  border-radius: var(--radius-md);
  margin: var(--spacing-lg) 0;
  border-left: 4px solid var(--color-accent);
  background: var(--color-accent-light);
}
.callout.amber {
  border-left-color: var(--color-amber);
  background: var(--color-amber-light);
}
.callout-title {
  font-family: var(--font-ui);
  font-weight: 700;
  font-size: 0.8125rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-accent);
  margin-bottom: var(--spacing-xs);
}
.callout.amber .callout-title { color: var(--color-amber); }

/* ===== Search Page ===== */
.search-page { margin-top: var(--spacing-lg); }
.search-page-form {
  display: flex;
  align-items: center;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--color-bg-subtle);
  width: 100%;
  max-width: 600px;
  margin: 0 auto;
  box-shadow: var(--shadow-xs);
  transition: border-color 0.2s, box-shadow 0.2s;
}
.search-page-form:focus-within {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px var(--color-focus-ring);
  background: var(--color-bg);
}
.search-page-input {
  flex: 1;
  border: none;
  background: transparent;
  font-family: var(--font-ui);
  font-size: 1rem;
  padding: 0.875em 1.125em;
  color: var(--color-text);
  outline: none;
  min-width: 0;
}
.search-page-input::placeholder { color: var(--color-muted); }
.search-btn-lg { padding: 0.875em 1em; color: var(--color-muted); }
.search-btn-lg:hover { color: var(--color-accent); }
.search-results { margin-top: var(--spacing-lg); }
.search-msg { font-family: var(--font-ui); color: var(--color-muted); font-size: 0.875rem; margin-bottom: var(--spacing-md); text-align: center; }
.search-summary { font-family: var(--font-ui); font-size: 0.8125rem; color: var(--color-muted); margin: var(--spacing-xs) 0 0; }