/* ============================================================
   JS Notes — stylesheet
   Design: "the margin notes" — a warm, highlighter-amber accent
   on an ink-navy reading surface, built for long-form learning.
   ============================================================ */

:root{
  --font-display: 'Space Grotesk', sans-serif;
  --font-body: 'Source Serif 4', Georgia, serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  --radius: 10px;
  --header-h: 64px;
  --sidebar-w: 280px;
  --toc-w: 240px;
  --max-content: 760px;
}

[data-theme="dark"]{
  --bg: #0F1420;
  --bg-raised: #161D2E;
  --bg-inset: #0A0E17;
  --border: #262f45;
  --text: #E9E6DE;
  --text-dim: #A7ADBE;
  --text-mute: #6E7789;
  --accent: #E8A33D;
  --accent-ink: #1B1300;
  --accent-2: #4FD1C5;
  --danger: #E8735B;
  --shadow: 0 10px 30px rgba(0,0,0,.35);
  --code-bg: #0A0E17;
}

[data-theme="white"]{
  --bg: #FFFFFF;
  --bg-raised: #F7F7F7;
  --bg-inset: #EFEFEF;
  --border: #DEDEDE;
  --text: #111111;
  --text-dim: #444444;
  --text-mute: #888888;
  --accent: #B5760A;
  --accent-ink: #FFF8EE;
  --accent-2: #0E8074;
  --danger: #C24328;
  --shadow: 0 10px 30px rgba(0,0,0,.10);
  --code-bg: #1A1A1A;
}

[data-theme="darker"]{
  --bg: #1A1A1A;
  --bg-raised: #242424;
  --bg-inset: #111111;
  --border: #333333;
  --text: #E8E8E8;
  --text-dim: #AAAAAA;
  --text-mute: #666666;
  --accent: #E8A33D;
  --accent-ink: #1B1300;
  --accent-2: #4FD1C5;
  --danger: #E8735B;
  --shadow: 0 10px 30px rgba(0,0,0,.5);
  --code-bg: #111111;
}

[data-theme="pink"]{
  --bg: #FDF0F5;
  --bg-raised: #FFF5F8;
  --bg-inset: #F9E3EC;
  --border: #F0C4D8;
  --text: #2D1520;
  --text-dim: #6B3A4E;
  --text-mute: #B07090;
  --accent: #C4286A;
  --accent-ink: #FFF0F5;
  --accent-2: #9B27AF;
  --danger: #D03030;
  --shadow: 0 10px 30px rgba(180,60,100,.12);
  --code-bg: #1A0B12;
}

*{ box-sizing: border-box; }
html{ scroll-behavior: smooth; }
body{
  margin:0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
a{ color: var(--accent-2); text-decoration: none; }
a:hover{ text-decoration: underline; }
img{ max-width:100%; }
::selection{ background: var(--accent); color: var(--accent-ink); }

/* ---------- Themed scrollbars (Firefox + WebKit) ---------- */
*{
  scrollbar-width: thin;
  scrollbar-color: var(--border) transparent;
}
::-webkit-scrollbar{ width: 11px; height: 11px; }
::-webkit-scrollbar-track{ background: transparent; }
::-webkit-scrollbar-corner{ background: transparent; }
::-webkit-scrollbar-thumb{
  background-color: var(--border);
  border-radius: 8px;
  border: 3px solid var(--bg);
  background-clip: padding-box;
}
::-webkit-scrollbar-thumb:hover{
  background-color: var(--text-mute);
  background-clip: padding-box;
}
/* Panels with a different surface color need a matching thumb border */
#sidebar::-webkit-scrollbar-thumb,
#toc::-webkit-scrollbar-thumb{ border-color: var(--bg); }
pre::-webkit-scrollbar{ height: 9px; }
pre::-webkit-scrollbar-thumb{
  background-color: var(--border);
  border: 2px solid var(--code-bg);
  background-clip: padding-box;
}
pre{ scrollbar-color: var(--border) transparent; }

/* ---------- Scroll progress ---------- */
#scroll-progress{
  position: fixed; top:0; left:0; height:3px; width:0%;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  z-index: 200; transition: width .1s linear;
}

/* ---------- Header ---------- */
#site-header{
  position: sticky; top:0; z-index: 150;
  height: var(--header-h);
  display:flex; align-items:center; gap:16px;
  padding: 0 20px;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.brand{
  display:flex; align-items:center; gap:10px;
  font-family: var(--font-display); font-weight:700; font-size:1.05rem;
  color: var(--text); white-space:nowrap;
}
.brand .mark{
  width:28px; height:28px; border-radius:8px;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  display:flex; align-items:center; justify-content:center;
  color:#0A0E17; font-weight:800; font-family: var(--font-mono); font-size:.85rem;
}
#menu-toggle{
  display:none; background:none; border:1px solid var(--border); border-radius:8px;
  width:36px; height:36px; color:var(--text); cursor:pointer;
}

#search-box{ position:relative; flex:1; max-width: 420px; margin-left: 8px; }
#search-input{
  width:100%; padding:9px 12px 9px 36px; border-radius:8px;
  border:1px solid var(--border); background: var(--bg-inset); color:var(--text);
  font-family: var(--font-body); font-size:.92rem;
}
#search-box::before{
  content:"⌕"; position:absolute; left:12px; top:50%; transform:translateY(-50%);
  color:var(--text-mute); font-size:1rem; pointer-events:none;
}
.kbd-hint{
  position:absolute; right:8px; top:50%; transform:translateY(-50%);
  font-family: var(--font-mono); font-size:.72rem; color:var(--text-mute);
  border:1px solid var(--border); border-radius:5px; padding:1px 5px;
  background: var(--bg-raised);
}
#search-results{
  display:none; position:absolute; top:calc(100% + 8px); left:0; right:0;
  background: var(--bg-raised); border:1px solid var(--border); border-radius:10px;
  box-shadow: var(--shadow); max-height: 340px; overflow:auto; z-index:100;
}
#search-results.show{ display:block; }
.search-hit{ display:flex; justify-content:space-between; gap:10px; padding:10px 14px; color:var(--text); border-bottom:1px solid var(--border); }
.search-hit:last-child{ border-bottom:none; }
.search-hit:hover{ background: var(--bg-inset); text-decoration:none; }
.hit-title{ font-family: var(--font-display); font-size:.9rem; }
.hit-cat{ font-size:.75rem; color: var(--text-mute); white-space:nowrap; }
.search-empty{ padding:14px; color:var(--text-mute); font-size:.85rem; }

.header-actions{ display:flex; align-items:center; gap:10px; margin-left:auto; }
#theme-toggle{
  width:38px; height:38px; border-radius:9px; border:1px solid var(--border);
  background: var(--bg-raised); color: var(--text); cursor:pointer; font-size:1rem;
  display:flex; align-items:center; justify-content:center;
}
#theme-toggle::after{ content:"🌙"; }
[data-theme="white"] #theme-toggle::after{ content:"☀️"; }
[data-theme="darker"] #theme-toggle::after{ content:"🌑"; }
[data-theme="pink"] #theme-toggle::after{ content:"🌸"; }

/* ---------- Layout ---------- */
#layout{
  display:grid;
  grid-template-columns: var(--sidebar-w) minmax(0,1fr) var(--toc-w);
  max-width: 1440px; margin:0 auto;
}
#sidebar{
  border-right: 1px solid var(--border);
  height: calc(100vh - var(--header-h));
  position: sticky; top: var(--header-h);
  overflow-y:auto; padding: 22px 14px;
}
.nav-cat{ margin-bottom: 4px; }
.nav-cat-toggle{
  width:100%; display:flex; align-items:center; justify-content:space-between;
  background:none; border:none; color: var(--text-dim); cursor:pointer;
  font-family: var(--font-display); font-size:.8rem; letter-spacing:.04em;
  text-transform: uppercase; padding: 10px 8px;
}
.nav-cat-toggle:hover{ color: var(--text); }
.chev{ transition: transform .18s ease; }
.nav-cat.open .chev{ transform: rotate(180deg); }
.nav-list{ list-style:none; margin:0; padding:0; max-height:0; overflow:hidden; }
.nav-cat.open .nav-list{ max-height: 900px; }
.nav-item{ font-size:.9rem; }
.nav-item a{
  display:block; color: var(--text-dim); padding:7px 10px 7px 14px;
  border-left: 2px solid transparent; border-radius: 0 6px 6px 0;
}
.nav-item a:hover{ color: var(--text); text-decoration:none; background: var(--bg-inset); }
.nav-item.active a{
  color: var(--accent); border-left-color: var(--accent);
  background: color-mix(in srgb, var(--accent) 10%, transparent);
  font-weight:600;
}
.nav-item.soon{
  display:flex; justify-content:space-between; padding:7px 10px 7px 14px;
  color: var(--text-mute); font-size:.87rem;
}
.tag{
  font-family: var(--font-mono); font-size:.65rem; border:1px solid var(--border);
  border-radius:4px; padding:1px 5px; color: var(--text-mute);
}

main{ min-width:0; padding: 40px clamp(20px,4vw,56px) 80px; }
#breadcrumb{ font-size:.85rem; color: var(--text-mute); margin-bottom: 18px; }
#breadcrumb a{ color: var(--text-mute); }
#breadcrumb .current{ color: var(--text); }
#breadcrumb .sep{ margin: 0 6px; }

#toc{
  border-left: 1px solid var(--border);
  height: calc(100vh - var(--header-h));
  position: sticky; top: var(--header-h);
  padding: 26px 20px; overflow-y:auto;
}
#toc.empty{ visibility:hidden; }
#toc h4{ font-family: var(--font-display); font-size:.78rem; text-transform:uppercase; letter-spacing:.05em; color: var(--text-mute); margin: 0 0 10px; }
#toc-list{ list-style:none; margin:0; padding:0; border-left:1px solid var(--border); }
#toc-list li a{
  display:block; font-size:.85rem; color: var(--text-dim); padding:6px 0 6px 14px;
}
#toc-list li a:hover{ color: var(--accent); text-decoration:none; }
#reading-time{
  display:block; margin-top: 20px; padding-top:16px; border-top:1px solid var(--border);
  font-size:.78rem; color: var(--text-mute);
}

/* ---------- Article typography ---------- */
article#content{ max-width: var(--max-content); }
#content h1{
  font-family: var(--font-display); font-size: clamp(1.9rem, 3vw, 2.5rem);
  margin: 0 0 6px; line-height:1.15;
}
.lede{ color: var(--text-dim); font-size:1.1rem; margin: 0 0 30px; }
#content h2{
  font-family: var(--font-display); font-size:1.4rem; margin: 46px 0 14px;
  padding-bottom:8px; border-bottom: 1px dashed var(--border);
  scroll-margin-top: calc(var(--header-h) + 16px);
}
#content h3{ font-family: var(--font-display); font-size:1.12rem; margin: 26px 0 10px; color: var(--text); }
#content p{ margin: 0 0 16px; color: var(--text); }
#content ul, #content ol{ margin: 0 0 16px; padding-left: 22px; }
#content li{ margin-bottom:6px; }
#content strong{ color: var(--accent); font-weight:700; }

/* callouts */
.callout{
  border-radius: var(--radius); padding: 14px 16px; margin: 18px 0;
  border: 1px solid var(--border); background: var(--bg-raised); font-size:.95rem;
}
.callout-title{ font-family: var(--font-display); font-weight:700; font-size:.85rem; text-transform:uppercase; letter-spacing:.03em; margin-bottom:6px; display:flex; align-items:center; gap:6px;}
.callout.tip{ border-left:3px solid var(--accent-2); }
.callout.tip .callout-title{ color: var(--accent-2); }
.callout.warn{ border-left:3px solid var(--danger); }
.callout.warn .callout-title{ color: var(--danger); }
.callout.note{ border-left:3px solid var(--accent); }
.callout.note .callout-title{ color: var(--accent); }

/* analogy / visual boxes */
.analogy{
  background: var(--bg-inset); border-radius: var(--radius); padding: 16px 18px; margin: 18px 0;
  border: 1px dashed var(--border);
}
.analogy .callout-title{ color: var(--text-dim); }

/* code */
/* Code blocks: the copy button lives in its own toolbar strip above the
   scrollable code, so it can never sit on top of (or get covered by) code
   or comments, no matter how long a line is or how far it's scrolled. */
.code-block{
  background: var(--code-bg); border-radius: var(--radius);
  margin: 14px 0; border:1px solid var(--border); overflow:hidden;
}
.code-toolbar{
  display:flex; align-items:center; justify-content:flex-end;
  padding: 7px 10px; gap:8px;
  background: color-mix(in srgb, var(--code-bg) 80%, white 6%);
  border-bottom: 1px solid color-mix(in srgb, var(--border) 60%, transparent);
}
.code-block pre{
  background: transparent; border-radius:0; padding: 16px 18px 18px;
  overflow-x:auto; margin:0; border:none;
}
/* Fallback: a bare <pre> not (yet) wrapped by JS still looks correct */
pre{
  background: var(--code-bg); border-radius: var(--radius); padding: 18px 18px 16px;
  overflow-x:auto; margin: 14px 0; border:1px solid var(--border);
}
code{ font-family: var(--font-mono); font-size:.86rem; }
:not(pre) > code{
  background: var(--bg-inset); padding: 2px 6px; border-radius:5px; color: var(--accent);
  border:1px solid var(--border);
}
pre code{ color:#E9E6DE; line-height:1.65; display:block; }
.copy-btn{
  flex-shrink:0; background: var(--bg-raised);
  color: var(--text-dim); border:1px solid var(--border); border-radius:6px;
  font-family: var(--font-mono); font-size:.7rem; padding:5px 10px; cursor:pointer;
  display:inline-flex; align-items:center; gap:5px; line-height:1;
  transition: background .15s ease, color .15s ease, border-color .15s ease;
}
.copy-btn:hover{ background: var(--bg-inset); color: var(--text); border-color: var(--text-mute); }
.copy-btn:active{ transform: translateY(1px); }
.copy-btn.copied{ color: var(--accent-2); border-color: var(--accent-2); }
/* minimal syntax highlight via span classes used in examples */
.tok-kw{ color:#E8A33D; } .tok-str{ color:#8FD19E; } .tok-com{ color:#6E7789; font-style:italic;}
.tok-num{ color:#4FD1C5; } .tok-fn{ color:#7FB0FF; }

/* explain-line breakdown blocks */
.line-breakdown{ list-style:none; margin: 10px 0 20px; padding:0; border-left:2px solid var(--accent); }
.line-breakdown li{ padding: 4px 0 4px 14px; font-size:.92rem; color: var(--text-dim); }
.line-breakdown code{ color: var(--accent); }

/* tables */
table{ width:100%; border-collapse:collapse; margin:16px 0; font-size:.92rem; }
th, td{ text-align:left; padding:9px 12px; border-bottom:1px solid var(--border); }
th{ font-family: var(--font-display); color: var(--text-dim); font-weight:600; }

/* quiz / exercise / challenge */
.exercise, .quiz, .challenge{
  border: 1px solid var(--border); border-radius: var(--radius); padding: 18px 20px; margin: 20px 0;
  background: var(--bg-raised);
}
.exercise h4, .quiz h4, .challenge h4{
  margin:0 0 10px; font-family: var(--font-display); font-size:.95rem;
  display:flex; align-items:center; gap:8px;
}
details.qa{ border-top:1px dashed var(--border); margin-top:10px; padding-top:10px; }
details.qa summary{ cursor:pointer; color: var(--accent-2); font-size:.9rem; }
details.qa p{ margin-top:8px; }

.related-list{ display:flex; flex-wrap:wrap; gap:8px; margin:10px 0 0; padding:0; list-style:none; }
.related-list a{
  display:inline-block; border:1px solid var(--border); border-radius:20px; padding:6px 14px;
  font-size:.85rem; color: var(--text-dim);
}
.related-list a:hover{ color:var(--accent); border-color: var(--accent); text-decoration:none; }

.mdn-ref{
  font-size:.82rem; color: var(--text-mute); margin-top:8px; padding-top:10px; border-top:1px solid var(--border);
}

/* prev/next pager */
#pager{ display:grid; grid-template-columns: 1fr 1fr; gap:14px; margin-top: 50px; }
.pager-btn{
  border:1px solid var(--border); border-radius: var(--radius); padding: 14px 16px;
  display:flex; flex-direction:column; gap:4px; color: var(--text);
}
.pager-btn:hover{ border-color: var(--accent); text-decoration:none; }
.pager-btn.next{ text-align:right; align-items:flex-end; }
.pager-label{ font-size:.72rem; color: var(--text-mute); font-family: var(--font-mono); }
.pager-title{ font-family: var(--font-display); font-size:.92rem; }

/* back to top */
#back-to-top{
  position: fixed; bottom: 26px; right: 26px; width:44px; height:44px; border-radius:50%;
  background: var(--accent); color: var(--accent-ink); border:none; font-size:1.1rem;
  cursor:pointer; opacity:0; pointer-events:none; transition: opacity .2s ease, transform .2s ease;
  box-shadow: var(--shadow); z-index:120;
}
#back-to-top.show{ opacity:1; pointer-events:auto; }
#back-to-top:hover{ transform: translateY(-3px); }

/* ---------- Home page ---------- */
.hero{ padding: 64px clamp(20px,5vw,80px) 30px; max-width:1100px; margin:0 auto; }
.hero .eyebrow{
  font-family: var(--font-mono); font-size:.8rem; color: var(--accent);
  text-transform:uppercase; letter-spacing:.08em; margin-bottom:14px; display:block;
}
.hero h1{ font-family: var(--font-display); font-size: clamp(2.4rem,5vw,3.6rem); line-height:1.08; margin:0 0 18px; max-width: 14ch; }
.hero p.sub{ font-size:1.15rem; color: var(--text-dim); max-width: 60ch; margin:0 0 30px; }
.hero-actions{ display:flex; gap:14px; flex-wrap:wrap; }
.btn{
  font-family: var(--font-display); font-weight:600; padding: 12px 22px; border-radius:9px;
  display:inline-block; border:1px solid var(--border);
}
.btn.primary{ background: var(--accent); color: var(--accent-ink); border-color:var(--accent); }
.btn.primary:hover{ text-decoration:none; filter:brightness(1.06); }
.btn.ghost{ color: var(--text); }
.btn.ghost:hover{ text-decoration:none; border-color: var(--accent); }

#progress-summary{ max-width: 460px; margin: 26px 0 0; }
.progress-track{ height:8px; border-radius:5px; background: var(--bg-inset); overflow:hidden; border:1px solid var(--border);}
.progress-fill{ height:100%; background: linear-gradient(90deg, var(--accent), var(--accent-2)); }
#progress-summary p{ font-size:.85rem; color: var(--text-mute); margin: 8px 0 0; }

.home-grid{
  max-width:1100px; margin: 30px auto 80px; padding: 0 clamp(20px,5vw,80px);
  display:grid; grid-template-columns: repeat(auto-fit, minmax(260px,1fr)); gap:18px;
}
.cat-card{
  border:1px solid var(--border); border-radius: 14px; padding:22px; background: var(--bg-raised);
}
.cat-card h3{ font-family: var(--font-display); margin:0 0 6px; font-size:1.05rem; }
.cat-card p{ color: var(--text-mute); font-size:.85rem; margin:0 0 14px; }
.cat-card .count{ font-family: var(--font-mono); font-size:.75rem; color: var(--accent); }

.feature-strip{
  max-width:1100px; margin:0 auto 70px; padding: 0 clamp(20px,5vw,80px);
  display:grid; grid-template-columns: repeat(auto-fit,minmax(200px,1fr)); gap:16px;
}
.feature{ padding:18px; border-left:2px solid var(--accent); }
.feature h4{ font-family: var(--font-display); margin:0 0 6px; font-size:.95rem; }
.feature p{ color: var(--text-mute); font-size:.85rem; margin:0; }

footer.site-footer{
  text-align:center; padding: 30px; color: var(--text-mute); font-size:.82rem;
  border-top:1px solid var(--border);
}

/* ---------- Responsive ---------- */
@media (max-width: 1100px){
  #layout{ grid-template-columns: var(--sidebar-w) minmax(0,1fr); }
  #toc{ display:none; }
}
@media (max-width: 860px){
  #menu-toggle{ display:flex; align-items:center; justify-content:center; }
  #layout{ grid-template-columns: 1fr; }
  #sidebar{
    position: fixed; left:0; top:var(--header-h); bottom:0; width: 84vw; max-width:320px;
    background: var(--bg); z-index: 140; transform: translateX(-100%); transition: transform .22s ease;
    box-shadow: var(--shadow);
  }
  #sidebar.open{ transform: translateX(0); }
  #search-box{ display:none; }
  main{ padding: 28px 18px 70px; }
  #pager{ grid-template-columns: 1fr; }
}