/* ============================================================
   Arnesia — Site Stylesheet
   ============================================================ */

/* --- Design tokens --- */
:root {
  /* Color */
  --bg-base: #F7F5EF;
  --bg-surface: #FFFFFF;
  --bg-subtle: #EFEBE0;
  --text-primary: #1A1A1A;
  --text-secondary: #5C5C5C;
  --text-muted: #8A8A8A;
  --border: #E2DDD0;
  --border-strong: #1A1A1A;
  --primary: #1A1A1A;
  --primary-hover: #000000;
  --accent: #2D5A8F;
  --accent-hover: #1F3F66;

  /* Typography */
  --font-display: 'Fraunces', 'Noto Serif JP', Georgia, serif;
  --font-body: 'Inter Tight', 'Noto Sans JP', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', Menlo, monospace;

  /* Spacing scale */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 1rem;
  --space-4: 1.5rem;
  --space-5: 2rem;
  --space-6: 3rem;
  --space-7: 4rem;
  --space-8: 6rem;
  --space-9: 8rem;

  /* Layout */
  --max-width: 1120px;
  --max-width-narrow: 720px;
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.7;
  color: var(--text-primary);
  background: var(--bg-base);
  /* Subtle dot grid for engineering character */
  background-image: radial-gradient(circle at 1px 1px, rgba(26, 26, 26, 0.04) 1px, transparent 0);
  background-size: 32px 32px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  font-feature-settings: 'palt' 1, 'kern' 1;
  text-rendering: optimizeLegibility;
}

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

ul,
ol {
  list-style: none;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.15s ease;
}

a:hover {
  color: var(--accent-hover);
}

/* --- Layout --- */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-5);
}

.container-narrow {
  max-width: var(--max-width-narrow);
  margin: 0 auto;
  padding: 0 var(--space-5);
}

/* --- Typography --- */
h1,
h2,
h3,
h4 {
  color: var(--text-primary);
  letter-spacing: -0.02em;
  line-height: 1.25;
  font-weight: 500;
}

h1 {
  font-family: var(--font-display);
  font-size: clamp(2.25rem, 5.5vw, 4rem);
  font-weight: 400;
  letter-spacing: -0.03em;
  line-height: 1.15;
}

h2 {
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 3vw, 2.25rem);
  font-weight: 400;
  letter-spacing: -0.025em;
  margin-bottom: var(--space-4);
}

h3 {
  font-family: var(--font-body);
  font-size: 1.125rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  margin-bottom: var(--space-2);
}

h4 {
  font-family: var(--font-body);
  font-size: 0.875rem;
  font-weight: 600;
  letter-spacing: 0;
}

p {
  color: var(--text-secondary);
  margin-bottom: var(--space-3);
}

p:last-child {
  margin-bottom: 0;
}

.eyebrow {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: var(--space-4);
}

.lead {
  font-size: 1.125rem;
  line-height: 1.75;
  color: var(--text-secondary);
  max-width: 52ch;
}

/* --- Header --- */
.site-header {
  border-bottom: 1px solid var(--border);
  background: var(--bg-base);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 1.25rem;
  padding-bottom: 1.25rem;
}

.brand {
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 500;
  color: var(--text-primary);
  letter-spacing: -0.01em;
}

.brand:hover {
  color: var(--text-primary);
}

.nav {
  display: flex;
  gap: var(--space-5);
  align-items: center;
}

.nav a {
  color: var(--text-primary);
  font-size: 0.95rem;
  font-weight: 400;
  position: relative;
}

.nav a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  right: 0;
  height: 1px;
  background: var(--text-primary);
  transform: scaleX(0);
  transition: transform 0.2s ease;
  transform-origin: left;
}

.nav a:hover {
  color: var(--text-primary);
}

.nav a:hover::after,
.nav a[aria-current='page']::after {
  transform: scaleX(1);
}

/* --- Hero --- */
.hero {
  padding: var(--space-9) 0 var(--space-8);
  border-bottom: 1px solid var(--border);
}

.hero h1 {
  margin-bottom: var(--space-5);
  max-width: 18ch;
}

.hero .lead {
  margin-bottom: var(--space-5);
}

/* --- Section base --- */
section {
  padding: var(--space-8) 0;
}

section + section {
  border-top: 1px solid var(--border);
}

.section-header {
  margin-bottom: var(--space-7);
  max-width: 60ch;
}

/* --- Buttons --- */
.btn {
  display: inline-block;
  padding: 0.875rem 1.5rem;
  background: var(--primary);
  color: var(--bg-base);
  font-family: var(--font-body);
  font-size: 0.95rem;
  font-weight: 500;
  border: 1px solid var(--primary);
  cursor: pointer;
  transition: background 0.15s ease, color 0.15s ease, transform 0.15s ease;
}

.btn:hover {
  background: var(--primary-hover);
  color: var(--bg-base);
}

.btn-outline {
  background: transparent;
  color: var(--text-primary);
}

.btn-outline:hover {
  background: var(--primary);
  color: var(--bg-base);
}

/* --- Product cards --- */
.product-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-4);
}

.product-card {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  padding: var(--space-6);
  display: flex;
  flex-direction: column;
  transition: border-color 0.15s ease, transform 0.15s ease;
}

.product-card:hover {
  border-color: var(--border-strong);
}

.product-card .product-tag {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: var(--space-3);
}

.product-card .product-name {
  font-family: var(--font-display);
  font-size: 1.875rem;
  font-weight: 400;
  letter-spacing: -0.02em;
  margin-bottom: var(--space-2);
  color: var(--text-primary);
}

.product-card .product-tagline {
  font-size: 0.95rem;
  color: var(--text-primary);
  margin-bottom: var(--space-3);
  font-weight: 500;
}

.product-card p {
  flex-grow: 1;
  font-size: 0.95rem;
}

.product-card .product-link {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  margin-top: var(--space-4);
  color: var(--text-primary);
  font-weight: 500;
  font-size: 0.95rem;
  align-self: flex-start;
}

.product-card .product-link::after {
  content: '→';
  transition: transform 0.15s ease;
}

.product-card .product-link:hover {
  color: var(--text-primary);
}

.product-card .product-link:hover::after {
  transform: translateX(4px);
}

/* --- Two-column layout --- */
.two-col {
  display: grid;
  grid-template-columns: 1fr 2fr;
  gap: var(--space-7);
  align-items: start;
}

/* --- Definition list (about info) --- */
.info-list {
  border-top: 1px solid var(--border);
}

.info-list > div {
  display: grid;
  grid-template-columns: 14ch 1fr;
  gap: var(--space-4);
  padding: var(--space-4) 0;
  border-bottom: 1px solid var(--border);
  align-items: baseline;
}

.info-list dt {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.info-list dd {
  font-size: 0.95rem;
  color: var(--text-primary);
}

/* --- Empty state --- */
.empty-state {
  padding: var(--space-8) 0;
  text-align: center;
  border: 1px dashed var(--border);
  background: var(--bg-surface);
}

.empty-state p {
  color: var(--text-muted);
}

/* --- Legal pages prose --- */
.prose h2 {
  font-family: var(--font-body);
  font-size: 1.25rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  margin-top: var(--space-6);
  margin-bottom: var(--space-3);
  padding-top: var(--space-5);
  border-top: 1px solid var(--border);
}

.prose h2:first-of-type {
  margin-top: 0;
  padding-top: 0;
  border-top: none;
}

.prose h3 {
  font-size: 1rem;
  margin-top: var(--space-4);
  margin-bottom: var(--space-2);
}

.prose p,
.prose li {
  color: var(--text-primary);
  font-size: 0.95rem;
  line-height: 1.8;
}

.prose ul,
.prose ol {
  padding-left: 1.5rem;
  margin-bottom: var(--space-3);
}

.prose ul {
  list-style: disc;
}

.prose ol {
  list-style: decimal;
}

.prose li {
  margin-bottom: var(--space-2);
}

.prose strong {
  font-weight: 600;
}

/* --- Footer --- */
.site-footer {
  border-top: 1px solid var(--border);
  padding: var(--space-7) 0 var(--space-5);
  margin-top: var(--space-9);
  background: var(--bg-subtle);
}

.site-footer .container {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--space-6);
}

.footer-brand .brand {
  display: inline-block;
  margin-bottom: var(--space-3);
}

.footer-brand p {
  font-size: 0.875rem;
  color: var(--text-muted);
  max-width: 32ch;
}

.site-footer h4 {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 500;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: var(--space-3);
}

.site-footer ul {
  list-style: none;
}

.site-footer li {
  margin-bottom: 0.5rem;
}

.site-footer a {
  color: var(--text-secondary);
  font-size: 0.875rem;
}

.site-footer a:hover {
  color: var(--text-primary);
}

.footer-bottom {
  border-top: 1px solid var(--border);
  padding-top: var(--space-4);
  margin-top: var(--space-5);
  font-size: 0.8rem;
  color: var(--text-muted);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-3);
}

.footer-bottom .container {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-3);
  grid-template-columns: none;
}

/* --- Responsive --- */
@media (max-width: 768px) {
  .product-grid {
    grid-template-columns: 1fr;
  }

  .two-col {
    grid-template-columns: 1fr;
    gap: var(--space-5);
  }

  .site-footer .container {
    grid-template-columns: 1fr 1fr;
  }

  .info-list > div {
    grid-template-columns: 1fr;
    gap: var(--space-1);
  }

  .hero {
    padding: var(--space-7) 0 var(--space-6);
  }

  section {
    padding: var(--space-7) 0;
  }
}

@media (max-width: 600px) {
  .site-header .container {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.75rem;
  }

  .nav {
    width: 100%;
    flex-wrap: wrap;
    gap: 0.75rem 1.25rem;
  }

  .nav a {
    font-size: 0.875rem;
  }

  .site-footer .container {
    grid-template-columns: 1fr;
    gap: var(--space-5);
  }

  .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
  }
}

/* ============================================================
   Blog: Card list (blog index)
   ============================================================ */

.blog-card-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-4);
}

.blog-card {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  padding: var(--space-5);
  display: flex;
  flex-direction: column;
  text-decoration: none;
  transition: border-color 0.15s ease, transform 0.15s ease;
}

.blog-card:hover {
  border-color: var(--border-strong);
  color: inherit;
}

.blog-card .blog-card-meta {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: var(--space-3);
}

.blog-card .blog-card-title {
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 400;
  letter-spacing: -0.02em;
  color: var(--text-primary);
  margin-bottom: var(--space-2);
  line-height: 1.3;
}

.blog-card .blog-card-excerpt {
  font-size: 0.95rem;
  color: var(--text-secondary);
  flex-grow: 1;
}

@media (max-width: 768px) {
  .blog-card-grid {
    grid-template-columns: 1fr;
  }
}

/* ============================================================
   Blog: Article (single post)
   ============================================================ */

.article {
  max-width: var(--max-width-narrow);
  margin: 0 auto;
  padding: 0 var(--space-5);
}

.article-header {
  padding: var(--space-7) 0 var(--space-5);
  border-bottom: 1px solid var(--border);
  margin-bottom: var(--space-6);
}

.article-meta {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: var(--space-3);
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
}

.article-meta .article-meta-item {
  display: inline-flex;
  align-items: center;
}

.article-title {
  font-family: var(--font-display);
  font-size: clamp(1.875rem, 4vw, 2.75rem);
  font-weight: 400;
  letter-spacing: -0.025em;
  line-height: 1.2;
  color: var(--text-primary);
  margin-bottom: 0;
}

/* Article body */
.article-body {
  font-size: 1rem;
  line-height: 1.85;
  color: var(--text-primary);
}

.article-body h2 {
  font-family: var(--font-body);
  font-size: 1.5rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  margin-top: var(--space-7);
  margin-bottom: var(--space-3);
  padding-top: var(--space-3);
}

.article-body h3 {
  font-family: var(--font-body);
  font-size: 1.125rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  margin-top: var(--space-5);
  margin-bottom: var(--space-2);
}

.article-body p {
  color: var(--text-primary);
  margin-bottom: var(--space-4);
}

.article-body ul,
.article-body ol {
  margin-bottom: var(--space-4);
  padding-left: 1.5rem;
}

.article-body ul {
  list-style: disc;
}

.article-body ol {
  list-style: decimal;
}

.article-body li {
  margin-bottom: var(--space-2);
  color: var(--text-primary);
}

.article-body a {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.article-body strong {
  font-weight: 600;
}

.article-body blockquote {
  border-left: 3px solid var(--border-strong);
  padding-left: var(--space-4);
  margin: var(--space-5) 0;
  color: var(--text-secondary);
  font-style: italic;
}

.article-body img {
  width: 100%;
  height: auto;
  margin: var(--space-5) 0;
  border: 1px solid var(--border);
}

.article-body hr {
  border: 0;
  border-top: 1px solid var(--border);
  margin: var(--space-6) 0;
}

/* Inline code */
.article-body :not(pre) > code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background: var(--bg-subtle);
  padding: 0.15em 0.4em;
  border: 1px solid var(--border);
  border-radius: 3px;
  color: var(--text-primary);
}

/* ============================================================
   Blog: Share buttons
   ============================================================ */

.article-share {
  margin-top: var(--space-7);
  padding-top: var(--space-5);
  border-top: 1px solid var(--border);
}

.article-share-label {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: var(--space-3);
}

.article-share-list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.article-share-list a,
.article-share-list button {
  display: inline-block;
  padding: 0.5rem 1rem;
  background: transparent;
  color: var(--text-primary);
  border: 1px solid var(--border-strong);
  font-family: var(--font-body);
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  text-decoration: none;
  transition: background 0.15s ease, color 0.15s ease;
}

.article-share-list a:hover,
.article-share-list button:hover {
  background: var(--primary);
  color: var(--bg-base);
}

/* ============================================================
   Blog: Article navigation (back to list)
   ============================================================ */

.article-nav {
  margin-top: var(--space-6);
  padding-top: var(--space-5);
  border-top: 1px solid var(--border);
}

.article-nav a {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--text-primary);
  font-weight: 500;
  text-decoration: none;
}

.article-nav a::before {
  content: '←';
}

.article-nav a:hover {
  color: var(--text-primary);
  text-decoration: underline;
}

/* ============================================================
   Prism.js: code block (dark theme override)
   ============================================================ */

.article-body pre[class*="language-"] {
  background: #1A1A1A !important;
  color: #F7F5EF;
  padding: var(--space-4);
  margin: var(--space-5) 0;
  border-radius: 0;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.875rem;
  line-height: 1.6;
  border: none;
}

.article-body pre[class*="language-"] code {
  background: transparent;
  border: none;
  padding: 0;
  color: inherit;
  font-family: inherit;
  font-size: inherit;
}