:root {
  --bg: #fdfdfc;
  --bg-elevated: #f5f5f3;
  --bg-overlay: rgba(253, 253, 252, 0.78);
  --fg: #18181b;
  --fg-soft: #27272a;
  --muted: #71717a;
  --subtle: #a1a1aa;
  --accent: #00677F;
  --accent-soft: rgba(0, 103, 127, 0.12);
  --border: #ececec;
  --border-strong: #d4d4d8;
  --selection: rgba(0, 103, 127, 0.18);
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.04);

  --max-width: 700px;
  --radius: 12px;
  --transition: 0.22s cubic-bezier(0.4, 0, 0.2, 1);

  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  color-scheme: light;
}

[data-theme="dark"] {
  --bg: #0b0b0d;
  --bg-elevated: #131316;
  --bg-overlay: rgba(11, 11, 13, 0.78);
  --fg: #fafafa;
  --fg-soft: #e4e4e7;
  --muted: #a1a1aa;
  --subtle: #71717a;
  --accent: #5EC5D6;
  --accent-soft: rgba(94, 197, 214, 0.16);
  --border: #1f1f23;
  --border-strong: #2e2e33;
  --selection: rgba(94, 197, 214, 0.25);
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.4);

  color-scheme: dark;
}

* { box-sizing: border-box; }

::selection { background: var(--selection); color: var(--fg); }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  font-feature-settings: "cv02", "cv03", "cv04", "cv11";
  transition: background-color var(--transition), color var(--transition);
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

main.container { flex: 1; }

a {
  color: inherit;
  text-decoration: none;
  transition: color var(--transition), opacity var(--transition);
}

a:hover { opacity: 0.7; }

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
  width: 100%;
}

/* ---------- Header ---------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--bg-overlay);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid var(--border);
  padding: 0.9rem 0;
  margin-bottom: 3rem;
}

.site-header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.site-title {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  font-weight: 600;
  font-size: 0.95rem;
  letter-spacing: -0.015em;
  color: var(--fg);
}

.site-title-mark {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 4px var(--accent-soft);
  flex-shrink: 0;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.site-nav a {
  color: var(--muted);
  font-size: 0.875rem;
  font-weight: 500;
}

.site-nav a:hover { color: var(--fg); opacity: 1; }

/* ---------- Theme toggle ---------- */

.theme-toggle {
  appearance: none;
  background: transparent;
  border: 0;
  padding: 0;
  margin: 0;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  color: var(--fg);
  font: inherit;
}

.theme-toggle-track {
  position: relative;
  display: inline-flex;
  align-items: center;
  width: 48px;
  height: 26px;
  background: var(--bg-elevated);
  border: 1px solid var(--border-strong);
  border-radius: 999px;
  transition: background-color var(--transition), border-color var(--transition);
}

.theme-toggle-icons {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 6px;
  pointer-events: none;
  color: var(--subtle);
}

.theme-toggle-icons .icon {
  width: 12px;
  height: 12px;
  transition: color var(--transition), opacity var(--transition);
}

.theme-toggle-icons .icon-sun { color: var(--fg); }
.theme-toggle-icons .icon-moon { color: var(--subtle); }

[data-theme="dark"] .theme-toggle-icons .icon-sun { color: var(--subtle); }
[data-theme="dark"] .theme-toggle-icons .icon-moon { color: var(--fg); }

.theme-toggle-thumb {
  position: absolute;
  top: 50%;
  left: 3px;
  transform: translateY(-50%);
  width: 20px;
  height: 20px;
  background: var(--bg);
  border: 1px solid var(--border-strong);
  border-radius: 50%;
  box-shadow: var(--shadow);
  transition: left var(--transition), background-color var(--transition);
  pointer-events: none;
}

[data-theme="dark"] .theme-toggle-thumb {
  left: calc(100% - 23px);
}

.theme-toggle:hover .theme-toggle-track {
  border-color: var(--accent);
}

.theme-toggle:focus-visible .theme-toggle-track {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* ---------- Hero ---------- */

.hero {
  position: relative;
  text-align: center;
  padding: 3rem 0 4rem;
  margin-bottom: 3rem;
  border-bottom: 1px solid var(--border);
}

.hero::before {
  content: "";
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 320px;
  height: 220px;
  background: radial-gradient(closest-side, var(--accent-soft), transparent);
  pointer-events: none;
  z-index: -1;
}

.hero-logo {
  margin: 0 auto 2rem;
  max-width: 200px;
  width: 100%;
}

.hero-logo svg {
  width: 100%;
  height: auto;
  color: var(--fg);
}

.hero-tagline {
  font-size: 1.5rem;
  font-weight: 700;
  line-height: 1.25;
  margin: 0 0 0.85rem;
  letter-spacing: -0.025em;
  color: var(--fg);
}

.hero-description {
  color: var(--muted);
  margin: 0 auto;
  max-width: 44ch;
  font-size: 1rem;
  line-height: 1.65;
}

/* ---------- Section title ---------- */

.section-title {
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--subtle);
  margin: 0 0 1.5rem;
  font-weight: 600;
}

/* ---------- Post list ---------- */

.post-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.post-item {
  padding: 1.65rem 0;
  border-bottom: 1px solid var(--border);
  transition: padding var(--transition);
}

.post-item:last-child { border-bottom: 0; }

.post-item-meta {
  display: flex;
  align-items: baseline;
  gap: 0.5rem;
  margin: 0 0 0.55rem;
  color: var(--subtle);
  font-size: 0.72rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-family: var(--font-mono);
}

.post-item-date,
.post-item-author {
  color: inherit;
}

.post-item-sep {
  color: var(--border-strong);
}

.post-item-title {
  margin: 0 0 0.5rem;
  font-size: 1.25rem;
  font-weight: 700;
  line-height: 1.3;
  letter-spacing: -0.02em;
}

.post-item-title a {
  color: var(--fg);
  background-image: linear-gradient(var(--accent), var(--accent));
  background-repeat: no-repeat;
  background-size: 0% 2px;
  background-position: 0 100%;
  transition: background-size var(--transition), color var(--transition), opacity var(--transition);
  padding-bottom: 2px;
}

.post-item-title a:hover {
  opacity: 1;
  background-size: 100% 2px;
  color: var(--fg);
}

.post-item-excerpt {
  color: var(--muted);
  font-size: 0.95rem;
  line-height: 1.65;
  margin: 0;
}

.empty {
  color: var(--muted);
  font-size: 0.95rem;
}

/* ---------- Archive ---------- */

.archive-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.archive-item {
  display: flex;
  align-items: baseline;
  gap: 1.5rem;
  padding: 0.9rem 0;
  border-bottom: 1px solid var(--border);
}

.archive-item:last-child { border-bottom: 0; }

.archive-item time {
  color: var(--subtle);
  font-size: 0.8rem;
  font-family: var(--font-mono);
  min-width: 6.5rem;
  flex-shrink: 0;
}

.archive-item a {
  color: var(--fg);
  font-weight: 500;
}

.archive-item a:hover { color: var(--accent); opacity: 1; }

/* ---------- Post ---------- */

.post { padding-top: 0.5rem; }

.post-header {
  margin-bottom: 2.75rem;
  padding-bottom: 1.75rem;
  border-bottom: 1px solid var(--border);
}

.post-title {
  font-size: 2.15rem;
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.03em;
  margin: 0 0 0.85rem;
}

.post-meta {
  color: var(--subtle);
  font-size: 0.8rem;
  font-family: var(--font-mono);
  margin: 0;
  display: flex;
  align-items: baseline;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.post-meta-sep {
  color: var(--border-strong);
}

.post-meta-author {
  color: var(--muted);
}

.post-content {
  font-size: 1.04rem;
  line-height: 1.78;
  color: var(--fg-soft);
}

.post-content h2 {
  font-size: 1.45rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin: 2.75rem 0 1rem;
  color: var(--fg);
}

.post-content h3 {
  font-size: 1.15rem;
  font-weight: 600;
  margin: 2rem 0 0.75rem;
  color: var(--fg);
}

.post-content p { margin: 0 0 1.25rem; }

.post-content strong { color: var(--fg); font-weight: 600; }

.post-content a {
  color: var(--accent);
  border-bottom: 1px solid var(--accent-soft);
}

.post-content a:hover {
  opacity: 1;
  border-bottom-color: var(--accent);
}

.post-content blockquote {
  margin: 1.75rem 0;
  padding: 0.25rem 0 0.25rem 1.25rem;
  border-left: 2px solid var(--accent);
  color: var(--muted);
  font-style: italic;
}

.post-content code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  padding: 0.12em 0.4em;
  border-radius: 5px;
}

.post-content pre {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem 1.15rem;
  overflow-x: auto;
  font-size: 0.875rem;
  line-height: 1.6;
  margin: 1.75rem 0;
}

.post-content pre code {
  background: transparent;
  border: 0;
  padding: 0;
  font-size: inherit;
}

.post-content img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius);
  margin: 1.75rem 0;
}

.post-content hr {
  border: 0;
  border-top: 1px solid var(--border);
  margin: 2.75rem 0;
}

.post-content ul,
.post-content ol {
  padding-left: 1.25rem;
  margin: 0 0 1.25rem;
}

.post-content li { margin-bottom: 0.35rem; }

.back-link {
  margin: 3.5rem 0 0;
  font-size: 0.9rem;
}

.back-link a {
  color: var(--muted);
  font-weight: 500;
}

.back-link a:hover { color: var(--accent); opacity: 1; }

/* ---------- Footer ---------- */

.site-footer {
  margin-top: 5rem;
  padding: 2rem 0;
  border-top: 1px solid var(--border);
}

.site-footer p {
  color: var(--subtle);
  font-size: 0.825rem;
  margin: 0;
  text-align: center;
}

/* ---------- Responsive ---------- */

@media (max-width: 540px) {
  .site-nav { gap: 1rem; }
  .site-nav a { font-size: 0.825rem; }
  .hero { padding: 1.5rem 0 3rem; margin-bottom: 2rem; }
  .hero-tagline { font-size: 1.2rem; }
  .post-title { font-size: 1.7rem; }
  .archive-item { flex-direction: column; gap: 0.15rem; }
  .archive-item time { min-width: 0; }
}