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

:root {
  --bg: #14161b;
  --panel: #1b1e20;
  --text: #eef2f0;
  --text-soft: rgba(238, 242, 240, 0.78);
  --muted: rgba(238, 242, 240, 0.54);
  --faint: rgba(238, 242, 240, 0.46);
  --line: rgba(238, 242, 240, 0.11);
  --line-strong: rgba(238, 242, 240, 0.17);
  --accent: #8ed7c5;
  --accent-blue: #75f7ff;
  --accent-green: #8ff0a4;
  --brand-blue: rgba(117, 247, 255, 0.78);
  --brand-green: rgba(143, 240, 164, 0.82);
  --accent-soft: rgba(142, 215, 197, 0.18);
  --font-sans: "Inter", "Hiragino Sans", "Yu Gothic", "Yu Gothic UI", "Noto Sans JP", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "Cascadia Code", Menlo, Consolas, monospace;
  --font-serif: "Hiragino Mincho ProN", "Hiragino Mincho Pro", "Yu Mincho", "Noto Serif JP", serif;
}

html {
  background: var(--bg);
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  line-height: 1.8;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

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

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

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

/* Shared chrome */

.home-wrap,
.article-wrap {
  width: min(100% - 40px, 680px);
  margin: 0 auto;
  padding: 44px 0 96px;
}

.article-wrap {
  width: min(100% - 40px, 700px);
}

.site-header {
  margin-bottom: 46px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--line);
}

.site-header-top {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 18px;
}

.site-name {
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 18px;
  font-weight: 500;
  letter-spacing: 0.01em;
}

.brand-m,
.brand-star {
  color: var(--brand-blue);
}

.brand-two {
  color: var(--brand-green);
}

.site-nav-links {
  display: flex;
  gap: 18px;
  color: var(--muted);
  font-size: 14px;
}

.site-nav-links a {
  transition: color 0.16s ease;
}

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

.header-language {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  margin-left: 2px;
  padding-left: 14px;
  border-left: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 11px;
}

.header-language .is-active {
  color: var(--accent);
}

.header-language a {
  color: var(--faint);
}

html[data-lang-preference="en"] [data-lang-row="ja"],
html:not([data-lang-preference="en"]) [data-lang-row="en"] {
  display: none;
}

.site-bio {
  max-width: 31rem;
  margin-top: 12px;
  color: var(--muted);
  font-size: 15px;
}

/* Index pages */

.home-section {
  margin-top: 38px;
}

.section-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 14px;
}

.section-label {
  margin: 0 0 14px;
  color: var(--faint);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.section-head .section-label {
  margin: 0;
}

.view-all {
  color: var(--faint);
  font-family: var(--font-mono);
  font-size: 12px;
  transition: color 0.16s ease;
}

.view-all:hover {
  color: var(--accent);
}

.connect-section p {
  max-width: 34rem;
  color: var(--text-soft);
  font-size: 15px;
  line-height: 1.8;
}

.connect-section a {
  color: var(--text);
  text-decoration: underline;
  text-decoration-color: rgba(238, 242, 240, 0.36);
  text-underline-offset: 0.18em;
}

.connect-section a:hover {
  color: var(--accent);
  text-decoration-color: rgba(142, 215, 197, 0.52);
}

.post-list,
.topic-index {
  display: flex;
  flex-direction: column;
  border-top: 1px solid var(--line);
}

.post-row,
.topic-row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  padding: 12px 0;
  border-bottom: 1px solid var(--line);
}

.post-main {
  display: flex;
  align-items: baseline;
  gap: 9px;
  min-width: 0;
}

.post-title,
.topic-name {
  color: var(--text-soft);
  font-size: 15px;
  transition: color 0.16s ease;
}

.title-number {
  color: inherit;
}

.post-title .title-number,
.article-header h1 .title-number {
  margin-right: 0.26em;
}

.post-row:hover .post-title,
.topic-row:hover .topic-name {
  color: var(--text);
}

.post-row time,
.topic-count,
.post-topic {
  color: var(--faint);
  font-family: var(--font-mono);
  font-size: 12px;
  white-space: nowrap;
}

.post-topic {
  font-size: 11px;
}

/* Article */

.article-header {
  margin-bottom: 46px;
  padding-bottom: 28px;
  border-bottom: 1px solid var(--line);
}

.article-topics {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 14px;
}

.article-topics a {
  color: var(--faint);
  font-family: var(--font-mono);
  font-size: 11px;
  transition: color 0.16s ease;
}

.article-topic-separator {
  color: var(--faint);
  font-family: var(--font-mono);
  font-size: 11px;
}

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

.article-header h1 {
  max-width: 670px;
  color: rgba(238, 242, 240, 0.88);
  font-size: clamp(28px, 4.5vw, 38px);
  font-weight: 400;
  line-height: 1.34;
}

.article-meta {
  margin-top: 13px;
  color: var(--faint);
  font-family: var(--font-mono);
  font-size: 12px;
}

.article-description {
  max-width: 620px;
  margin-top: 22px;
  color: var(--muted);
  font-size: 16px;
  line-height: 1.85;
}

.article-body {
  color: var(--text-soft);
  font-size: 17px;
  line-height: 1.98;
}

.article-body > * + * {
  margin-top: 1.28em;
}

.article-body h2,
.article-body h3 {
  color: rgba(238, 242, 240, 0.9);
  font-weight: 500;
  line-height: 1.45;
}

/* 見出しに連番は振らない（エッセイの声に合わせ、仕様書的な装飾を外す）。
   節の区切りは罫線でなく、ゆとりのある余白だけで示す。 */
.article-body h2 {
  margin-top: 3.4em;
  font-size: 19px;
}

.article-body h3 {
  margin-top: 2.1em;
  font-size: 18px;
}

.article-body a {
  color: var(--accent);
  text-decoration: underline;
  text-decoration-color: rgba(142, 215, 197, 0.35);
  text-underline-offset: 0.18em;
}

.article-body strong {
  color: var(--text);
  font-weight: 700;
}

.article-body em {
  color: rgba(238, 242, 240, 0.9);
}

.article-body .term-note {
  margin-left: 0.08em;
  color: var(--accent);
  font-size: 0.72em;
  font-weight: 500;
  line-height: 0;
  vertical-align: super;
}

.article-body ul,
.article-body ol {
  padding-left: 1.35rem;
}

.article-body li + li {
  margin-top: 0.36em;
}

.article-body blockquote {
  margin: 1.65em 0;
  padding-left: 1rem;
  border-left: 2px solid rgba(142, 215, 197, 0.52);
  color: var(--muted);
}

.article-body code {
  padding: 0.1em 0.35em;
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.045);
  color: var(--text);
  font-family: var(--font-mono);
  font-size: 0.9em;
}

.article-body pre {
  overflow-x: auto;
  margin: 1.7em 0;
  padding: 1.1rem 1.2rem;
  border: 1px solid var(--line);
  background: rgba(6, 8, 10, 0.32) !important;
  border-radius: 6px;
}

.article-body pre code {
  padding: 0;
  border: 0;
  background: transparent;
}

.article-body figure {
  margin: 2.25em 0;
}

.article-body img {
  display: block;
  width: 100%;
  border: 1px solid var(--line-strong);
  border-radius: 6px;
  background: rgba(255, 255, 255, 0.03);
}

.article-body figcaption {
  margin-top: 0.7rem;
  color: var(--faint);
  font-size: 13px;
  line-height: 1.65;
}

.article-body table {
  width: 100%;
  border-collapse: collapse;
  font-size: 15px;
}

.article-body th,
.article-body td {
  padding: 0.62rem 0.75rem;
  border-bottom: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

.article-body th {
  color: var(--text);
}

.article-body h2:last-of-type:has(+ ol) + ol {
  color: var(--muted);
  font-size: 14px;
  line-height: 1.75;
}

/* データ図を本文幅より広く見せたい時は <figure class="wide">。GIF は通常幅のままでよい。 */
.article-body figure.wide {
  width: min(100vw - 40px, 1000px);
  margin-left: 50%;
  transform: translateX(-50%);
}

/* Series prev/next (連載の前後ナビ) */

.series-nav {
  display: flex;
  align-items: baseline;
  gap: 18px;
  margin-top: 64px;
  padding-top: 26px;
  border-top: 1px solid var(--line);
  font-size: 14px;
  line-height: 1.5;
}

.series-nav a {
  max-width: 47%;
  color: var(--muted);
  transition: color 0.16s ease;
}

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

.series-next {
  margin-left: auto;
  text-align: right;
}

.series-dir {
  color: var(--faint);
  font-family: var(--font-mono);
}

/* Font demo */

.font-demo {
  display: grid;
  gap: 18px;
}

.font-card {
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: rgba(255, 255, 255, 0.025);
}

.font-card.recommended {
  border-color: rgba(142, 215, 197, 0.34);
  background: rgba(142, 215, 197, 0.045);
}

.font-card h2 {
  margin: 0 0 12px;
  padding: 0;
  border: 0;
  color: var(--accent);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.font-sample {
  color: var(--text-soft);
  font-size: 18px;
  line-height: 1.9;
}

.font-sample p + p {
  margin-top: 1em;
}

.font-sample .sample-lead {
  color: var(--text);
  font-size: 20px;
  line-height: 1.72;
}

.font-sample .sample-en {
  color: rgba(238, 242, 240, 0.72);
}

.font-sample.sans {
  font-family: var(--font-sans);
}

.font-sample.paco-sans {
  font-family: "Inter", "Hiragino Sans", "Yu Gothic", "Noto Sans JP", sans-serif;
  font-weight: 400;
}

.font-sample.noto-sans {
  font-family: "Noto Sans JP", "Inter", "Hiragino Sans", "Yu Gothic", sans-serif;
  font-weight: 400;
}

.font-sample.hiragino-mincho {
  font-family: "Hiragino Mincho ProN", "Hiragino Mincho Pro", "Yu Mincho", "Noto Serif JP", serif;
}

.font-sample.noto-serif {
  font-family: "Noto Serif JP", "Hiragino Mincho ProN", "Yu Mincho", serif;
}

.font-sample.newsreader-accent {
  font-family: "Inter", "Hiragino Sans", "Yu Gothic", "Noto Sans JP", sans-serif;
}

.font-sample.newsreader-accent .sample-en {
  font-family: "Newsreader", Georgia, serif;
  font-size: 21px;
  font-style: italic;
  line-height: 1.75;
}

.font-note {
  margin-top: 10px;
  color: var(--faint);
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.6;
}

/* Background demo */

.background-demo-wrap {
  width: min(100% - 40px, 860px);
}

.background-demo {
  display: grid;
  gap: 20px;
}

.bg-swatch {
  display: grid;
  grid-template-columns: minmax(9rem, 0.34fr) minmax(0, 1fr);
  overflow: hidden;
  min-height: 18rem;
  border: 1px solid var(--line);
  background: var(--demo-bg);
}

.bg-meta {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 18px;
  padding: 22px;
  border-right: 1px solid rgba(238, 242, 240, 0.1);
  background: rgba(0, 0, 0, 0.08);
}

.bg-meta span {
  color: rgba(238, 242, 240, 0.86);
  font-size: 15px;
  font-weight: 500;
  line-height: 1.4;
}

.bg-meta code {
  display: block;
  color: rgba(188, 194, 200, 0.72);
  font-size: 12px;
}

.bg-sample {
  padding: 24px 26px;
  background:
    radial-gradient(circle at 50% -18%, rgba(142, 215, 197, 0.045), transparent 24rem),
    var(--demo-bg);
}

.bg-sample h2 {
  margin: 0 0 1.3rem;
  padding: 0 0 1.1rem;
  border-bottom: 1px solid rgba(238, 242, 240, 0.1);
  color: rgba(238, 242, 240, 0.9);
  font-size: 22px;
  font-weight: 500;
  line-height: 1.4;
}

.bg-sample p {
  max-width: 36rem;
  color: rgba(238, 242, 240, 0.76);
  font-size: 16px;
  line-height: 1.92;
}

.bg-sample p + p {
  margin-top: 0.95em;
}

.bg-sample .sample-en {
  color: rgba(188, 194, 200, 0.62);
  font-size: 14px;
}

.bg-note {
  grid-column: 2;
  margin: 0;
  padding: 0 26px 24px;
  color: rgba(188, 194, 200, 0.68);
  font-size: 13px;
  line-height: 1.7;
  background: var(--demo-bg);
}

.bg-recommended {
  border-color: rgba(142, 215, 197, 0.28);
}

@media (max-width: 600px) {
  .home-wrap,
  .article-wrap {
    width: min(100% - 36px, 680px);
    padding-top: 32px;
    padding-bottom: 78px;
  }

  .site-header {
    margin-bottom: 36px;
  }

  .site-header-top {
    align-items: flex-start;
  }

  .site-nav-links {
    gap: 14px;
    font-size: 13px;
  }

  .post-row time {
    display: none;
  }

  .post-main {
    flex-direction: column;
    gap: 2px;
  }

  .article-header {
    margin-bottom: 36px;
  }

  .article-body {
    font-size: 16px;
    line-height: 1.92;
  }

  .background-demo-wrap {
    width: min(100% - 28px, 680px);
  }

  .bg-swatch {
    grid-template-columns: 1fr;
  }

  .bg-meta {
    flex-direction: row;
    align-items: baseline;
    padding: 16px 18px;
    border-right: 0;
    border-bottom: 1px solid rgba(238, 242, 240, 0.1);
  }

  .bg-sample {
    padding: 20px 18px;
  }

  .bg-note {
    grid-column: 1;
    padding: 0 18px 20px;
  }
}