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

:root {
  --bg: #09090b;
  --surface: #141416;
  --surface-hover: #1e1e22;
  --border: rgba(255, 255, 255, 0.06);
  --text: #f4f4f5;
  --text-secondary: #a1a1aa;
  --accent: #fafafa;
  --radius: 12px;
}

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    Oxygen, Ubuntu, Cantarell, "Open Sans", "Helvetica Neue", sans-serif;
  line-height: 1.7;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

a {
  color: inherit;
  text-decoration: none;
  transition: color 0.15s ease;
}

a:hover {
  color: var(--text-secondary);
}

p {
  color: var(--text-secondary);
  line-height: 1.7;
}

h1, h2, h3 {
  color: var(--text);
  font-weight: 600;
  letter-spacing: -0.02em;
}

/* ── Header ────────────────────────────────────────── */

body > header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(9, 9, 11, 0.8);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  padding: 0 1.5rem;
}

body > header > div {
  max-width: 720px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 56px;
}

.logo a {
  font-size: 1.05rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--text);
}

.logo a:hover {
  color: var(--text);
  opacity: 0.8;
}

nav {
  display: flex;
  gap: 0.25rem;
}

nav a {
  padding: 6px 14px;
  border-radius: 8px;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: background 0.15s ease, color 0.15s ease;
}

nav a:hover {
  background: var(--surface-hover);
  color: var(--text);
}

/* ── Main ──────────────────────────────────────────── */

main {
  flex: 1;
  padding: 4rem 1.5rem 6rem;
}

/* ── Footer ────────────────────────────────────────── */

body > footer {
  border-top: 1px solid var(--border);
  padding: 2rem 1.5rem;
  text-align: center;
}

body > footer p {
  font-size: 0.8125rem;
  margin-bottom: 0.5rem;
}

body > footer a {
  color: var(--text-secondary);
}

body > footer a:hover {
  color: var(--text);
}

/* ── Container ─────────────────────────────────────── */

.container {
  max-width: 720px;
  margin: 0 auto;
}

.container-narrow {
  max-width: 640px;
  margin: 0 auto;
}

/* ── Homepage Hero ─────────────────────────────────── */

.hero {
  text-align: center;
  padding: 2rem 0 3rem;
}

.hero img {
  width: 96px;
  height: 96px;
  border-radius: 50%;
  margin-bottom: 1.5rem;
  border: 2px solid var(--border);
}

.hero h1 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
  letter-spacing: -0.03em;
}

.hero-role {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  margin-bottom: 1rem;
}

.hero p {
  max-width: 480px;
  margin: 0 auto 1.5rem;
  font-size: 1.05rem;
}

.hero .social {
  display: flex;
  justify-content: center;
  gap: 0.5rem;
}

.hero .social a {
  padding: 6px 16px;
  border-radius: 8px;
  font-size: 0.875rem;
  font-weight: 500;
  background: var(--surface);
  color: var(--text-secondary);
  transition: background 0.15s ease, color 0.15s ease;
}

.hero .social a:hover {
  background: var(--surface-hover);
  color: var(--text);
}

/* ── Section Cards ─────────────────────────────────── */

.section {
  margin-bottom: 3rem;
}

.section-title {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-secondary);
  margin-bottom: 1rem;
}

.card-list {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.card {
  display: block;
  padding: 1rem 1.25rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: background 0.15s ease, border-color 0.15s ease;
}

.card:hover {
  background: var(--surface-hover);
  border-color: rgba(255, 255, 255, 0.1);
}

.card-row {
  display: flex;
  align-items: flex-start;
  gap: 0.5rem;
}

.card-title {
  font-weight: 600;
  font-size: 0.9375rem;
  color: var(--text);
  flex: 1;
}

.card-desc {
  font-size: 0.8125rem;
  margin-top: 0.375rem;
}

.card-tag {
  display: inline-block;
  font-size: 0.6875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 2px 8px;
  border-radius: 4px;
  white-space: nowrap;
  flex-shrink: 0;
}

.tag-ongoing {
  background: rgba(250, 204, 21, 0.12);
  color: #facc15;
}

.tag-published {
  background: rgba(74, 222, 128, 0.12);
  color: #4ade80;
}

/* ── Blog List ─────────────────────────────────────── */

.blog-header {
  margin-bottom: 2rem;
}

.blog-header h1 {
  font-size: 1.75rem;
}

.blog-list {
  list-style: none;
  display: flex;
  flex-direction: column;
}

.blog-list li {
  border-bottom: 1px solid var(--border);
  padding: 1.25rem 0;
}

.blog-list li:first-child {
  padding-top: 0;
}

.blog-list a {
  font-size: 1.05rem;
  font-weight: 600;
  display: block;
  margin-bottom: 0.25rem;
}

.blog-list time {
  font-size: 0.8125rem;
  color: var(--text-secondary);
}

/* ── Article (Post) ────────────────────────────────── */

article {
  padding-top: 1rem;
}

article > header {
  margin-bottom: 2.5rem;
}

article > header h1 {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  margin-bottom: 0.5rem;
}

article > header time {
  font-size: 0.875rem;
  color: var(--text-secondary);
}

article > header .author {
  color: var(--text-secondary);
  font-size: 0.875rem;
}

article h1,
article h2,
article h3 {
  margin-top: 2rem;
  margin-bottom: 0.75rem;
}

article h1 { font-size: 1.75rem; }
article h2 { font-size: 1.35rem; }
article h3 { font-size: 1.1rem; }

article p {
  margin-bottom: 1.25rem;
}

article ul,
article ol {
  margin-bottom: 1.25rem;
  padding-left: 1.5rem;
  color: var(--text-secondary);
}

article li {
  margin-bottom: 0.5rem;
}

article table {
  color: var(--text-secondary);
}

article table th {
  color: var(--text);
  font-weight: 600;
}

mjx-container {
  color: var(--text);
  overflow-x: auto;
  overflow-y: hidden;
  max-width: 100%;
}

mjx-container[display="true"] {
  margin: 1.25rem 0;
}

article blockquote {
  border-left: 2px solid var(--border);
  padding-left: 1rem;
  margin: 1.5rem 0;
  color: var(--text-secondary);
  font-style: italic;
}

article code {
  background: var(--surface);
  padding: 0.15em 0.4em;
  border-radius: 4px;
  font-size: 0.875em;
  font-family: "SF Mono", "Fira Code", "Fira Mono", Menlo, Consolas, monospace;
  color: var(--text);
}

article pre {
  background: var(--surface);
  padding: 1rem 1.25rem;
  border-radius: var(--radius);
  overflow-x: auto;
  margin-bottom: 1.25rem;
  border: 1px solid var(--border);
}

article pre code {
  background: none;
  padding: 0;
  font-size: 0.8125rem;
}

article img {
  max-width: 100%;
  border-radius: var(--radius);
  margin: 1.5rem 0;
}

article hr {
  margin: 2.5rem 0;
  border: 0;
  border-top: 1px solid var(--border);
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
  font-size: 0.875rem;
  color: var(--text-secondary);
  margin-bottom: 2rem;
  transition: color 0.15s ease;
}

.back-link:hover {
  color: var(--text);
}

/* ── 404 ───────────────────────────────────────────── */

.error-page {
  text-align: center;
  padding-top: 3rem;
}

.error-page h1 {
  font-size: 4rem;
  font-weight: 700;
  letter-spacing: -0.04em;
  margin-bottom: 0.5rem;
}

.error-page p {
  font-size: 1.05rem;
  margin-bottom: 2rem;
}

.error-page a {
  padding: 10px 24px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-weight: 500;
  font-size: 0.875rem;
  transition: background 0.15s ease;
}

.error-page a:hover {
  background: var(--surface-hover);
  color: var(--text);
}

/* ── Responsive ────────────────────────────────────── */

@media (max-width: 640px) {
  body > header {
    padding: 0 1rem;
  }

  body > header > div {
    height: 52px;
  }

  .logo a {
    font-size: 0.9375rem;
  }

  nav {
    gap: 0;
  }

  nav a {
    padding: 5px 10px;
    font-size: 0.8125rem;
  }

  main {
    padding: 2.5rem 1rem 4rem;
  }

  .hero {
    padding: 1rem 0 2rem;
  }

  .hero h1 {
    font-size: 1.5rem;
  }

  .hero-role {
    font-size: 0.875rem;
  }

  .hero p {
    font-size: 0.9375rem;
    max-width: 100%;
  }

  .hero .social {
    flex-wrap: wrap;
  }

  .hero .social a {
    font-size: 0.8125rem;
    padding: 5px 14px;
  }

  .section-title {
    font-size: 0.6875rem;
  }

  .card {
    padding: 0.875rem 1rem;
  }

  .card-title {
    font-size: 0.875rem;
  }

  .card-row {
    flex-wrap: wrap;
    gap: 0.375rem;
  }

  .card-tag {
    font-size: 0.625rem;
    padding: 2px 6px;
  }

  .card-desc {
    font-size: 0.75rem;
  }

  .blog-header h1 {
    font-size: 1.5rem;
  }

  .blog-list a {
    font-size: 0.9375rem;
  }

  article > header h1 {
    font-size: 1.35rem;
  }

  article h1 { font-size: 1.35rem; }
  article h2 { font-size: 1.1rem; }
  article h3 { font-size: 1rem; }

  article p {
    font-size: 0.9375rem;
  }

  article table {
    display: block;
    overflow-x: auto;
    white-space: nowrap;
    -webkit-overflow-scrolling: touch;
    font-size: 0.75rem;
  }

  article pre {
    padding: 0.75rem 1rem;
    font-size: 0.75rem;
  }

  article pre code {
    font-size: 0.75rem;
  }

  article code {
    font-size: 0.8125em;
  }

  article hr {
    margin: 2rem 0;
  }

  body > footer {
    padding: 1.5rem 1rem;
    font-size: 0.75rem;
  }

  .error-page h1 {
    font-size: 3rem;
  }

  mjx-container {
    font-size: 0.9375rem;
  }
}

@media (max-width: 400px) {
  .logo a {
    font-size: 0.875rem;
  }

  nav a {
    padding: 4px 8px;
    font-size: 0.75rem;
  }

  .hero h1 {
    font-size: 1.35rem;
  }

  .hero p {
    font-size: 0.875rem;
  }

  article > header h1 {
    font-size: 1.2rem;
  }
}