/* ===== 上野裕太郎 Blog — sakana.ai風レイアウト（本体サイトと同トーン） ===== */

:root {
  --bg: #ffffff;
  --bg-alt: #f6f6f4;
  --ink: #14140f;
  --ink-soft: #55554d;
  --ink-faint: #8a8a80;
  --line: #e6e6e0;
  --accent: #c8503c;
  --accent-soft: #f3e4df;
  --max: 1000px;
  --pad: clamp(20px, 5vw, 40px);
  --font-jp: "Noto Sans JP", "Inter", system-ui, sans-serif;
  --font-en: "Inter", "Noto Sans JP", system-ui, sans-serif;
  color-scheme: light;
}

:root[data-theme="dark"] {
  --bg: #141412;
  --bg-alt: #1e1e1b;
  --ink: #f2f1ec;
  --ink-soft: #bdbcb3;
  --ink-faint: #8a897f;
  --line: #302f2a;
  --accent: #e0715c;
  --accent-soft: #3a2420;
  color-scheme: dark;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-jp);
  color: var(--ink);
  background: var(--bg);
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  transition: background-color .3s ease, color .3s ease;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; height: auto; }

/* ===== Header (centered wordmark band, sakana-style) ===== */
.blog-header {
  position: relative;
  border-bottom: 1px solid var(--line);
  background: var(--bg-alt);
  padding: 52px var(--pad);
  text-align: center;
}

/* ===== Theme toggle ===== */
.theme-toggle {
  position: absolute;
  top: 24px;
  right: var(--pad);
  width: 38px; height: 38px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--line);
  border-radius: 50%;
  background: transparent;
  color: var(--ink-soft);
  cursor: pointer;
  transition: color .2s, border-color .2s;
}
.theme-toggle:hover { color: var(--accent); border-color: var(--accent); }
.theme-toggle svg { width: 18px; height: 18px; }
.theme-toggle .icon-sun { display: none; fill: none; stroke: currentColor; stroke-width: 2; stroke-linecap: round; }
.theme-toggle .icon-moon { display: block; fill: currentColor; }
:root[data-theme="dark"] .theme-toggle .icon-sun { display: block; }
:root[data-theme="dark"] .theme-toggle .icon-moon { display: none; }
.blog-logo {
  font-size: clamp(38px, 7vw, 60px);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--ink);
  display: inline-block;
  line-height: 1.05;
}

/* ===== Category nav ===== */
.category-nav {
  max-width: var(--max);
  margin: 40px auto 8px;
  padding: 0 var(--pad);
  display: flex;
  flex-wrap: wrap;
  gap: 26px;
  font-size: 15px;
}
.category-nav a {
  color: var(--ink-faint);
  padding-bottom: 4px;
  transition: color .15s;
}
.category-nav a:hover { color: var(--ink); }
.category-nav a.is-active {
  color: var(--ink);
  border-bottom: 1.5px solid var(--accent);
}

/* ===== Post list ===== */
.post-list {
  max-width: var(--max);
  margin: 24px auto 90px;
  padding: 0 var(--pad);
}
.post {
  padding: 44px 0;
  border-bottom: 1px solid var(--line);
}
.post:first-child { padding-top: 24px; }
.post__title {
  font-size: clamp(22px, 3.4vw, 30px);
  font-weight: 700;
  letter-spacing: -0.01em;
  line-height: 1.35;
  color: var(--ink);
  transition: color .15s;
}
.post__title:hover { color: var(--accent); }
.post__meta {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-top: 10px;
  font-size: 14px;
  color: var(--ink-faint);
}
.post__cat { color: var(--accent); font-weight: 600; }
.post__thumb {
  display: block;
  width: 100%;
  border-radius: 8px;
  margin-top: 24px;
  overflow: hidden;
  border: 1px solid var(--line);
}
.post__thumb img { display: block; width: 100%; height: auto; }
.post__excerpt {
  margin-top: 18px;
  font-size: 16px;
  color: var(--ink-soft);
  max-width: 760px;
}
.post__more {
  display: inline-block;
  margin-top: 18px;
  font-size: 15px;
  color: var(--accent);
  font-weight: 600;
}
.post__more::after { content: " →"; }
.post-empty { color: var(--ink-faint); padding: 40px 0; }

/* ===== Footer (sakana-style bar) ===== */
.blog-footer {
  border-top: 1px solid var(--line);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 20px var(--pad);
}
.blog-footer__left {
  font-family: var(--font-en);
  font-size: 13px;
  color: var(--ink-faint);
}
.blog-footer__social { display: flex; align-items: center; gap: 16px; }
.blog-footer__social a {
  display: inline-flex;
  color: var(--ink-faint);
  transition: color .2s, transform .2s;
}
.blog-footer__social a:hover { color: var(--accent); transform: translateY(-2px); }
.blog-footer__social svg { width: 18px; height: 18px; fill: currentColor; }

/* ===== Article page ===== */
.article {
  max-width: 760px;
  margin: 0 auto;
  padding: 56px var(--pad) 90px;
}
.article__back {
  font-family: var(--font-en);
  font-size: 14px;
  color: var(--ink-faint);
  transition: color .2s;
}
.article__back:hover { color: var(--accent); }
.article__title {
  font-size: clamp(28px, 5vw, 38px);
  font-weight: 700;
  line-height: 1.3;
  letter-spacing: -0.01em;
  margin-top: 20px;
}
.article__meta {
  margin-top: 14px;
  font-size: 14px;
  color: var(--ink-faint);
}
.article__hero {
  margin: 36px 0;
  border-radius: 8px;
  overflow: hidden;
  border: 1px solid var(--line);
}
.article__hero img { display: block; width: 100%; }
.article__body h2 {
  font-size: 24px;
  font-weight: 700;
  margin: 42px 0 14px;
}
.article__body h3 {
  font-size: 19px;
  font-weight: 600;
  margin: 32px 0 10px;
}
.article__body p {
  margin: 16px 0;
  font-size: 17px;
  color: var(--ink-soft);
}
.article__body ul,
.article__body ol {
  margin: 16px 0 16px 24px;
  font-size: 17px;
  color: var(--ink-soft);
}
.article__body li { margin: 6px 0; }
.article__body a { color: var(--accent); text-decoration: underline; }
.article__body strong { color: var(--ink); font-weight: 600; }
.article__body blockquote {
  margin: 20px 0;
  padding: 8px 20px;
  border-left: 3px solid var(--accent);
  color: var(--ink-soft);
  background: var(--bg-alt);
}
.article__body img {
  display: block;
  max-width: 100%;
  height: auto;
  margin: 24px 0;
  border: 1px solid var(--line);
  border-radius: 8px;
}