/* ── Reset & Base ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg:          #0f1117;
  --bg-card:     #1a1d27;
  --bg-code:     #12151e;
  --bg-code-alt: rgba(255,255,255,0.02);
  --border:      #2a2d3e;
  --accent:      #f97316;
  --accent-dim:  #7c3a0e;
  --text:        #e2e4ef;
  --text-muted:  #6b7299;
  --text-code:   #a8d8a8;
  --keyword:     #c792ea;
  --string:      #c3e88d;
  --comment:     #546e7a;
  --fn:          #82aaff;
  --tag:         #f07178;
  --nu:          #f78c6c;
  --nav-bg:      rgba(15, 17, 23, 0.92);
  --nav-h:       56px;
  --radius:      8px;
  --gap:         1.5rem;
}

[data-theme="light"] {
  --bg:          #f4f5f7;
  --bg-card:     #ffffff;
  --bg-code:     #eceef2;
  --bg-code-alt: rgba(0,0,0,0.025);
  --border:      #d0d4de;
  --accent:      #d4600a;
  --accent-dim:  #fde4cc;
  --text:        #1a1d27;
  --text-muted:  #5a6080;
  --text-code:   #2d6e2d;
  --keyword:     #7c3aad;
  --string:      #357a1e;
  --comment:     #7a8a9a;
  --fn:          #1a52c4;
  --tag:         #b02020;
  --nu:          #c2410c;
  --nav-bg:      rgba(244, 245, 247, 0.92);
}

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
  font-size: 14px;
  line-height: 1.6;
}

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

/* ── Nav ── */
header {
  position: sticky;
  top: 0;
  z-index: 100;
}

nav {
  background: var(--nav-bg);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
  height: var(--nav-h);
  display: flex;
  align-items: center;
  padding: 0 1.5rem;
  gap: 1rem;
}

.nav-brand {
  font-weight: 700;
  font-size: 1rem;
  color: var(--accent);
  white-space: nowrap;
  letter-spacing: 0.02em;
  flex-shrink: 0;
}

.nav-brand span { color: var(--text); font-weight: 700; }

.nav-links {
  display: flex;
  flex-wrap: nowrap;
  gap: 0.25rem;
  overflow-x: auto;
  scrollbar-width: none;
  list-style: none;
}

.nav-links::-webkit-scrollbar { display: none; }

.nav-links a {
  color: var(--text-muted);
  font-size: 0.78rem;
  padding: 0.3rem 0.6rem;
  border-radius: 4px;
  white-space: nowrap;
  transition: color 0.15s, background 0.15s;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--text);
  background: var(--border);
  text-decoration: none;
}

.nav-links a.active {
  color: var(--accent);
}

/* ── Burger button ── */
.burger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.4rem;
  flex-shrink: 0;
}

.burger span {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--text-muted);
  border-radius: 2px;
  transition: transform 0.22s ease, opacity 0.22s ease;
}

.burger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.burger.open span:nth-child(2) { opacity: 0; transform: scaleX(0); }
.burger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ── Theme toggle ── */
.theme-toggle {
  margin-left: auto;
  flex-shrink: 0;
  background: var(--bg-code);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 0.3rem 0.75rem;
  font-size: 0.78rem;
  color: var(--text-muted);
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.4rem;
  transition: color 0.15s, background 0.15s, border-color 0.15s;
  white-space: nowrap;
}

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

.theme-toggle .toggle-icon { font-size: 0.9rem; }

/* ── Anchor copy button ── */
.anchor-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  margin-left: 0.4rem;
  padding: 0.15rem 0.35rem;
  background: none;
  border: 1px solid transparent;
  border-radius: 4px;
  color: var(--text-muted);
  cursor: pointer;
  font-size: 0.78rem;
  opacity: 0;
  transition: opacity 0.15s, color 0.15s, border-color 0.15s, background 0.15s;
  vertical-align: middle;
  flex-shrink: 0;
}

.section-title:hover .anchor-btn,
.anchor-btn:focus {
  opacity: 1;
}

.anchor-btn:hover {
  color: var(--accent);
  border-color: var(--border);
  background: var(--bg-code);
}

.anchor-btn.copied {
  opacity: 1;
  color: var(--string);
  border-color: var(--border);
  background: var(--bg-code);
}

/* ── Layout ── */
.wrapper {
  max-width: 1280px;
  margin: 0 auto;
  padding: 2rem 1.5rem 4rem;
}

.hero {
  text-align: center;
  padding: 2.5rem 0 2rem;
}

.hero h1 {
  font-size: clamp(1.6rem, 4vw, 2.4rem);
  font-weight: 700;
  color: var(--text);
}

.hero h1 em {
  color: var(--accent);
  font-style: normal;
}

.hero p {
  color: var(--text-muted);
  margin-top: 0.5rem;
  font-size: 0.9rem;
}

/* ── Grid ── */
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(min(100%, 560px), 1fr));
  gap: var(--gap);
  margin-top: var(--gap);
}

.grid-wide {
  grid-column: 1 / -1;
}

.grid-sub {
  margin-top: 1rem;
}

/* ── Section ── */
section {
  scroll-margin-top: calc(var(--nav-h) + 1rem);
  margin-top: 3rem;
}

section:first-of-type {
  margin-top: 0;
}

.section-title {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--accent);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.section-title .icon {
  font-size: 1.1rem;
}

/* ── Card ── */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.card-title {
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--accent);
  margin-bottom: -0.25rem;
}

/* ── Code Block ── */
pre {
  background: var(--bg-code);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem 1.1rem;
  overflow-x: auto;
  font-family: 'Cascadia Code', 'Fira Code', 'Consolas', monospace;
  font-size: 0.82rem;
  line-height: 1.7;
}

code {
  font-family: inherit;
}

.kw  { color: var(--keyword); }
.str { color: var(--string); }
.fn  { color: var(--fn); }
.cm  { color: var(--comment); font-style: italic; }
.tg  { color: var(--tag); }
.ac  { color: var(--accent); }
.nu  { color: var(--nu); }

/* ── Card description ── */
.card-desc {
  font-size: 0.82rem;
  color: var(--text-muted);
  margin-bottom: 0.25rem;
}

/* ── Inline code ── */
p code, li code, td code {
  background: var(--bg-code);
  border: 1px solid var(--border);
  border-radius: 3px;
  padding: 0.1em 0.35em;
  font-size: 0.85em;
  color: var(--text-code);
}

/* ── Table ── */
.table-wrap { overflow-x: auto; }

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.82rem;
}

th, td {
  border: 1px solid var(--border);
  padding: 0.55rem 0.75rem;
  text-align: left;
  vertical-align: top;
}

th {
  background: var(--bg-code);
  color: var(--accent);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-weight: 600;
}

tr:nth-child(even) td { background: var(--bg-code-alt); }

/* ── List ── */
ul.clean { list-style: none; display: flex; flex-direction: column; gap: 0.4rem; }
ul.clean li::before { content: '›'; color: var(--accent); margin-right: 0.5rem; }

/* ── Tag Pills ── */
.pills { display: flex; flex-wrap: wrap; gap: 0.4rem; }
.pill {
  background: var(--bg-code);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 0.2rem 0.65rem;
  font-size: 0.75rem;
  color: var(--text-muted);
  font-family: monospace;
}
.pill.accent { border-color: var(--accent-dim); color: var(--accent); }

/* ── Note / Tip ── */
.note {
  background: rgba(249, 115, 22, 0.08);
  border-left: 3px solid var(--accent);
  border-radius: 0 4px 4px 0;
  padding: 0.6rem 0.9rem;
  font-size: 0.82rem;
  color: var(--text-muted);
}

.note strong { color: var(--text); }

/* ── Description list ── */
dl { display: grid; grid-template-columns: auto 1fr; gap: 0.35rem 1rem; font-size: 0.83rem; }
dt { color: var(--fn); font-family: monospace; white-space: nowrap; padding-top: 0.05rem; }
dd { color: var(--text-muted); }

/* ── Back to top ── */
.back-to-top {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  z-index: 99;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--text-muted);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s, color 0.15s, border-color 0.15s, background 0.15s;
}

.back-to-top.visible {
  opacity: 1;
  pointer-events: auto;
}

.back-to-top:hover {
  color: var(--accent);
  border-color: var(--accent);
  background: var(--bg-code);
}

/* ── Footer ── */
footer {
  text-align: center;
  margin-top: 3rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 0.78rem;
}

/* ── Responsive ── */
@media (max-width: 640px) {
  :root { --gap: 1rem; }
  .wrapper { padding: 1.25rem 1rem 3rem; }
  .nav-brand span { display: none; }
  .hero { padding: 1.5rem 0 1rem; }
}

@media (max-width: 768px) {
  .burger { display: flex; }

  .nav-links {
    position: absolute;
    top: var(--nav-h);
    left: 0;
    right: 0;
    flex-direction: column;
    flex-wrap: wrap;
    gap: 0.15rem;
    background: var(--bg-card);
    border-bottom: 1px solid var(--border);
    padding: 0;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.28s ease, padding 0.28s ease;
  }

  .nav-links.open {
    max-height: 480px;
    padding: 0.6rem 0.75rem;
  }

  .nav-links a {
    font-size: 0.85rem;
    padding: 0.5rem 0.6rem;
    border-radius: 6px;
  }

  .theme-toggle .toggle-label { display: none; }
}