:root {
  --bg: #090d16;
  --card-bg: #111827;
  --card-inner: #0b1120;
  --border: #1f293d;
  --border-accent: rgba(56, 189, 248, 0.4);
  --text: #e2e8f0;
  --text-muted: #94a3b8;
  --heading: #f8fafc;
  --accent: #38bdf8;
  --accent-hover: #7dd3fc;
  --accent-green: #10b981;
  --code-bg: #030712;
  --badge-near: #facc15;
  --badge-gap: #f87171;
  --navbar-bg: rgba(9, 13, 22, 0.85);
  --nav-pill-bg: rgba(56, 189, 248, 0.1);
  --nav-pill-border: rgba(56, 189, 248, 0.25);
  --btn-secondary-bg: #111827;
  --btn-secondary-hover: #1e293b;
  --btn-secondary-border: #1f293d;
  --btn-secondary-text: #f8fafc;
  color-scheme: dark;
}

[data-theme="light"] {
  --bg: #f8fafc;
  --card-bg: #ffffff;
  --card-inner: #f1f5f9;
  --border: #e2e8f0;
  --border-accent: rgba(2, 132, 199, 0.4);
  --text: #334155;
  --text-muted: #64748b;
  --heading: #0f172a;
  --accent: #0284c7;
  --accent-hover: #0369a1;
  --accent-green: #059669;
  --code-bg: #0f172a;
  --badge-near: #b45309;
  --badge-gap: #be123c;
  --navbar-bg: rgba(248, 250, 252, 0.88);
  --nav-pill-bg: rgba(2, 132, 199, 0.08);
  --nav-pill-border: rgba(2, 132, 199, 0.25);
  --btn-secondary-bg: #ffffff;
  --btn-secondary-hover: #f1f5f9;
  --btn-secondary-border: #cbd5e1;
  --btn-secondary-text: #0f172a;
  color-scheme: light;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

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

.container {
  max-width: 1040px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Navbar */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--navbar-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  padding: 0.75rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1.5rem;
}

.nav-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-weight: 700;
  font-size: 1.2rem;
  color: var(--heading);
  text-decoration: none;
  flex-shrink: 0;
}
.nav-brand:hover { text-decoration: none; }

.nav-logo {
  width: 30px;
  height: 30px;
  background: linear-gradient(135deg, #38bdf8, #10b981);
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
}

.nav-scroll {
  display: flex;
  align-items: center;
  gap: 1.25rem;
}

.nav-links {
  display: flex;
  gap: 1.25rem;
  align-items: center;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-links a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 500;
  transition: color 0.15s ease;
  white-space: nowrap;
}
.nav-links a:hover, .nav-links a.active { color: var(--heading); text-decoration: none; }

.nav-pill {
  padding: 0.35rem 0.75rem;
  background: var(--nav-pill-bg);
  border: 1px solid var(--nav-pill-border);
  border-radius: 6px;
  color: var(--accent) !important;
  font-weight: 600 !important;
}

/* Theme Toggle */
.theme-toggle {
  background: var(--card-inner);
  border: 1px solid var(--border);
  border-radius: 6px;
  width: 34px;
  height: 34px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  color: var(--heading);
  font-size: 16px;
  flex-shrink: 0;
  transition: all 0.15s ease;
}
.theme-toggle:hover { border-color: var(--accent); }
.theme-icon-system, .theme-icon-sun, .theme-icon-moon { display: none; }
[data-theme-mode="system"] .theme-icon-system { display: inline; }
[data-theme-mode="light"] .theme-icon-sun { display: inline; }
[data-theme-mode="dark"] .theme-icon-moon { display: inline; }
:root:not([data-theme-mode]) .theme-icon-system { display: inline; }

.theme-toggle-mobile { display: flex; }
.theme-toggle-desktop { display: none; }

@media (min-width: 961px) {
  .theme-toggle-mobile { display: none !important; }
  .theme-toggle-desktop { display: flex !important; }
}
@media (max-width: 960px) {
  .navbar {
    padding: 0.6rem 1rem;
    flex-direction: column;
    align-items: stretch;
    gap: 0.5rem;
  }
  .nav-top { width: 100%; }
  .nav-scroll {
    width: 100%;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    padding-bottom: 0.2rem;
    justify-content: flex-start;
  }
  .nav-links { gap: 0.85rem; }
  .theme-toggle-mobile { display: flex !important; }
  .theme-toggle-desktop { display: none !important; }
}

/* Content */
.page-content {
  padding: 3rem 1.5rem;
  min-height: calc(100vh - 180px);
}

.page-content h1 {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--heading);
  letter-spacing: -0.025em;
  margin-bottom: 1.25rem;
}

.page-content h2 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--heading);
  letter-spacing: -0.02em;
  margin-top: 2.5rem;
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border);
  scroll-margin-top: 5rem;
}

.page-content h3 {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--heading);
  margin-top: 2rem;
  margin-bottom: 0.75rem;
  scroll-margin-top: 5rem;
}

.page-content h4 {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--heading);
  margin-top: 1.5rem;
  margin-bottom: 0.5rem;
  scroll-margin-top: 5rem;
}

.page-content p {
  margin-bottom: 1rem;
}

.page-content ul, .page-content ol {
  margin-bottom: 1.25rem;
  padding-left: 1.75rem;
}

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

.page-content hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 2.5rem 0;
}

.page-content blockquote {
  border-left: 3px solid var(--accent);
  padding: 0.6rem 1rem;
  background: var(--card-inner);
  border-radius: 0 6px 6px 0;
  color: var(--text-muted);
  margin-bottom: 1.25rem;
}

/* Tables: a table wider than the screen scrolls inside its own box instead of
   being clipped by the page (body hides horizontal overflow). */
.page-content table {
  display: block;
  max-width: 100%;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  border-collapse: collapse;
  margin: 1.5rem 0;
  font-size: 0.9rem;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
}

.page-content th, .page-content td {
  padding: 0.75rem 1rem;
  border: 1px solid var(--border);
  text-align: left;
}

.page-content th {
  background: var(--card-inner);
  color: var(--heading);
  font-weight: 600;
}

.page-content td code {
  white-space: nowrap;
}

.page-content p, .page-content li, .page-content td {
  overflow-wrap: break-word;
}

.page-content tr:nth-child(even) td {
  background: var(--card-inner);
}

/* Code */
code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
  font-size: 0.88em;
  background: var(--card-inner);
  color: var(--accent);
  padding: 0.15rem 0.35rem;
  border-radius: 4px;
  border: 1px solid var(--border);
}

pre {
  position: relative;
  color: #e2e8f0;
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1rem 1.25rem;
  overflow-x: auto;
  margin: 1.25rem 0;
  line-height: 1.5;
}

/* The code background is dark in both themes, so code text is light in both. */
pre code {
  background: transparent;
  border: none;
  padding: 0;
  color: #e2e8f0;
  font-size: 0.85rem;
  white-space: pre;
}

.page-content .highlighter-rouge { margin: 1.25rem 0; }
.page-content .highlighter-rouge pre { margin: 0; }

/* Rouge token colours (kramdown syntax_highlighter: rouge), on the dark code background */
.highlight .c, .highlight .c1, .highlight .cm, .highlight .cs, .highlight .ch, .highlight .cp { color: #8b9ab0; font-style: italic; }
.highlight .k, .highlight .kd, .highlight .kn, .highlight .kr, .highlight .kt, .highlight .kc { color: #7dd3fc; }
.highlight .s, .highlight .s1, .highlight .s2, .highlight .sb, .highlight .sh, .highlight .se, .highlight .si, .highlight .sx { color: #86efac; }
.highlight .m, .highlight .mi, .highlight .mf, .highlight .mh, .highlight .il { color: #fca5a5; }
.highlight .na, .highlight .nt, .highlight .py, .highlight .nl { color: #fbbf24; }
.highlight .nb, .highlight .nf, .highlight .nc, .highlight .nn { color: #c4b5fd; }
.highlight .o, .highlight .p { color: #cbd5e1; }
.highlight .gd { color: #fca5a5; }
.highlight .gi { color: #86efac; }
.highlight .err { color: #fca5a5; background: transparent; }

@media (max-width: 768px) {
  .page-content { padding: 2rem 1rem; }
  .page-content h1 { font-size: 1.75rem; }
  .page-content h2 { font-size: 1.3rem; }
  .page-content th, .page-content td { padding: 0.55rem 0.7rem; }
  pre { padding: 0.85rem 1rem; }
  pre code { font-size: 0.8rem; }
}

/* Code blocks keep a dark background in both themes, so their text and
   the copy button use fixed light colors rather than theme tokens. */
.copy-wrap {
  position: relative;
}
.copy-wrap > pre { padding-right: 3rem; }
.copy-btn {
  position: absolute;
  top: 0.45rem;
  right: 0.45rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1.9rem;
  height: 1.9rem;
  padding: 0;
  background: rgba(15, 23, 42, 0.85);
  border: 1px solid #334155;
  border-radius: 6px;
  color: #94a3b8;
  cursor: pointer;
  opacity: 0.75;
  transition: opacity 0.15s ease, color 0.15s ease, border-color 0.15s ease;
}
.copy-wrap:hover .copy-btn,
.copy-btn:focus-visible { opacity: 1; }
.copy-btn:hover { color: #e2e8f0; border-color: #64748b; }
.copy-btn:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.copy-btn.copied { color: #34d399; border-color: #34d399; opacity: 1; }
.copy-btn svg { width: 15px; height: 15px; }

/* Footer */
footer {
  border-top: 1px solid var(--border);
  padding: 2.5rem 0;
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-muted);
  background: var(--card-bg);
}

footer a {
  color: var(--accent);
  text-decoration: none;
}
footer a:hover {
  text-decoration: underline;
}