/* ============================================================
   lab-notes — design tokens
   A researcher's notebook: pale graph-paper background, ink-navy
   text, an amber "highlighter" accent, and a teal "signal" accent
   borrowed from an EEG trace (used once, as the scroll indicator).
   ============================================================ */

:root{
  --bg:        #f4f3ef;
  --paper:     #ffffff;
  --ink:       #24231f;
  --ink-soft:  #5b5a54;
  --ink-faint: #8b8a82;
  --accent:    #b9791f;   /* highlighter amber — links, tags, active states */
  --accent-soft: #b9791f1a;
  --signal:    #217f77;   /* EEG-trace teal — used once, deliberately */
  --signal-soft: #217f7724;
  --line:      #e3e2db;
  --code-bg:   #24231f;
  --code-fg:   #ece9df;
  --code-accent: #7fd6c9;
  --shadow:    0 1px 0 rgba(22,33,43,0.06);
  --radius:    3px;
  --page-max:  90rem;
  --font-display: 'Roboto', ui-sans-serif, system-ui, -apple-system, sans-serif;
  --font-body:    'Roboto', ui-sans-serif, system-ui, -apple-system, sans-serif;
  --font-mono:    'IBM Plex Mono', ui-monospace, 'SFMono-Regular', Menlo, monospace;
}

[data-theme="dark"]{
  --bg:        #262624;
  --paper:     #2f2f2c;
  --ink:       #f7f6f2;
  --ink-soft:  #b9b7ad;
  --ink-faint: #83817a;
  --accent:    #e0a94c;
  --accent-soft: #e0a94c22;
  --signal:    #58c6ba;
  --signal-soft: #58c6ba24;
  --line:      #3d3d39;
  --code-bg:   #1c1c1a;
  --code-fg:   #ece9df;
  --code-accent: #7fd6c9;
  --shadow:    0 1px 0 rgba(0,0,0,0.3);
}

*{ box-sizing: border-box; }
html{ scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce){
  html{ scroll-behavior: auto; }
  *{ animation-duration: 0.001ms !important; transition-duration: 0.001ms !important; }
}

body{
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

a{ color: var(--accent); text-decoration-thickness: 1px; text-underline-offset: 2px; }
a:hover{ color: var(--ink); }

::selection{ background: var(--accent-soft); }

/* ---------- masthead ---------- */

.masthead{
  position: sticky; top: 0; z-index: 20;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(6px);
  border-bottom: 1px solid var(--line);
}
.masthead-row{
  max-width: var(--page-max); margin: 0 auto;
  padding: 0.85rem 1.25rem 0.7rem;
  display: flex; align-items: baseline; gap: 1rem; justify-content: space-between;
}
.wordmark{
  font-family: var(--font-mono); font-size: 0.95rem; font-weight: 500;
  color: var(--ink); text-decoration: none; letter-spacing: 0.02em;
  display: inline-flex; align-items: baseline; gap: 0.4em;
}
.wordmark .glyph{ color: var(--signal); }
.wordmark .sub{ color: var(--ink-faint); font-size: 0.78em; font-weight: 400; }
.masthead-tools{ display: flex; align-items: center; gap: 0.9rem; }

.theme-toggle{
  font-family: var(--font-mono); font-size: 0.78rem; color: var(--ink-soft);
  background: transparent; border: 1px solid var(--line); border-radius: var(--radius);
  padding: 0.3em 0.6em; cursor: pointer;
}
.theme-toggle:hover{ border-color: var(--ink-soft); color: var(--ink); }

/* signature element: the EEG scroll-trace */
.trace-wrap{ height: 26px; max-width: var(--page-max); margin: 0 auto; padding: 0 1.25rem; }
.trace-wrap svg{ width: 100%; height: 100%; display: block; }
.trace-bg{ stroke: var(--line); stroke-width: 1.2; fill: none; }
.trace-fg{ stroke: var(--signal); stroke-width: 1.6; fill: none;
  filter: drop-shadow(0 0 3px var(--signal-soft)); }

/* ---------- index page ---------- */

.wrap{ max-width: var(--page-max); margin: 0 auto; padding: 2.25rem 1.25rem 6rem; }

.lede{ max-width: 56rem; margin: 0 0 1.9rem; }
.lede h1{ font-family: var(--font-display); font-weight: 600; font-size: 1.85rem;
  margin: 0 0 0.35rem; letter-spacing: -0.01em; }
.lede p{ color: var(--ink-soft); margin: 0; font-size: 1.02rem; }

.controls{ display: flex; flex-wrap: wrap; gap: 0.6rem; align-items: center;
  margin: 0 0 1.6rem; }
.search{
  font-family: var(--font-mono); font-size: 0.85rem; color: var(--ink);
  background: var(--paper); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 0.5em 0.75em; min-width: 15rem; flex: 1 1 15rem;
}
.search::placeholder{ color: var(--ink-faint); }
.search:focus, .theme-toggle:focus, .tag-chip:focus, a:focus, button:focus{
  outline: 2px solid var(--signal); outline-offset: 2px;
}

.tags{ display: flex; flex-wrap: wrap; gap: 0.4rem; margin: 0 0 2rem; }
.tag-chip{
  font-family: var(--font-mono); font-size: 0.74rem; color: var(--ink-soft);
  background: transparent; border: 1px solid var(--line); border-radius: 999px;
  padding: 0.3em 0.75em; cursor: pointer;
}
.tag-chip:hover{ border-color: var(--accent); color: var(--accent); }
.tag-chip[aria-pressed="true"]{
  background: var(--accent-soft); border-color: var(--accent); color: var(--ink);
}

.note-list{ list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--line); }
.note-item{ border-bottom: 1px solid var(--line); }
.note-item a{
  display: block; padding: 1.1rem 0.1rem; text-decoration: none; color: inherit;
}
.note-item a:hover .note-title{ color: var(--accent); }
.note-meta{
  font-family: var(--font-mono); font-size: 0.74rem; color: var(--ink-faint);
  display: flex; gap: 0.9rem; margin-bottom: 0.3rem;
}
.note-title{
  font-family: var(--font-display); font-size: 1.28rem; font-weight: 600;
  color: var(--ink); margin: 0 0 0.3rem; line-height: 1.3;
}
.note-excerpt{ color: var(--ink-soft); margin: 0; font-size: 0.96rem; }
.note-tags{ margin-top: 0.5rem; display: flex; gap: 0.5rem; flex-wrap: wrap; }
.note-tags span{
  font-family: var(--font-mono); font-size: 0.7rem; color: var(--signal);
  background: var(--signal-soft); padding: 0.15em 0.55em; border-radius: 999px;
}
.empty-state{ padding: 2.5rem 0.1rem; color: var(--ink-faint); font-family: var(--font-mono);
  font-size: 0.88rem; }

/* ---------- note page ---------- */

.note-layout{
  max-width: var(--page-max); margin: 0 auto; padding: 2.25rem 1.5rem 8rem;
}
.note-header{ margin-bottom: 0.5rem; }
.back-link{
  font-family: var(--font-mono); font-size: 0.78rem; color: var(--ink-soft);
  text-decoration: none; display: inline-flex; align-items: center; gap: 0.4em;
}
.back-link:hover{ color: var(--accent); }
.note-header-meta{
  font-family: var(--font-mono); font-size: 0.76rem; color: var(--ink-faint);
  margin: 1.1rem 0 0.25rem; display: flex; gap: 0.9rem; flex-wrap: wrap;
}
.note-header h1{
  font-family: var(--font-display); font-weight: 600; font-size: 2.15rem;
  line-height: 1.2; letter-spacing: -0.01em; margin: 0.2rem 0 0.9rem;
}

.note-toc{
  font-family: var(--font-mono); font-size: 0.78rem;
  border: 1px solid var(--line); border-radius: var(--radius);
  padding: 0.9rem 1.1rem; margin: 0.5rem 0 2.2rem; background: var(--paper);
}
.note-toc-label{ color: var(--ink-faint); text-transform: uppercase; letter-spacing: 0.08em;
  font-size: 0.68rem; margin-bottom: 0.6rem; }
.note-toc ol{
  list-style: none; margin: 0; padding: 0;
  display: flex; flex-wrap: wrap; gap: 0.35rem 1.4rem;
}
.note-toc li{ margin: 0; }
.note-toc a{
  display: inline-block; padding: 0.15rem 0; color: var(--ink-soft); text-decoration: none;
  border-bottom: 1px solid transparent;
}
.note-toc a[data-level="3"]{ font-size: 0.73rem; opacity: 0.85; }
.note-toc a[data-level="3"]::before{ content: '› '; opacity: 0.6; }
.note-toc a:hover{ color: var(--ink); }
.note-toc a.active{ color: var(--signal); border-bottom-color: var(--signal); }

.note-body{ font-size: 1.4rem; }
.note-body > *:first-child{ margin-top: 0; }
.note-body h2, .note-body h3{
  font-family: var(--font-display); font-weight: 600; color: var(--ink);
  scroll-margin-top: 5.5rem;
}
.note-body h2{ font-size: 1.65rem; margin: 2.4rem 0 0.9rem; padding-top: 0.4rem;
  border-top: 1px solid var(--line); }
.note-body h2:first-of-type{ border-top: none; padding-top: 0; margin-top: 1.4rem; }
.note-body h3{ font-size: 1.14rem; margin: 1.8rem 0 0.6rem; }
.note-body p{ margin: 0 0 1.05rem; color: var(--ink); }
.note-body ul, .note-body ol{ margin: 0 0 1.05rem; padding-left: 1.3rem; }
.note-body li{ margin: 0.3rem 0; }
.note-body li::marker{ color: var(--ink-faint); }
.note-body strong{ color: var(--ink); font-weight: 700; }
.note-body blockquote{
  margin: 1.3rem 0; padding: 0.3rem 1rem; border-left: 3px solid var(--signal);
  color: var(--ink-soft); background: var(--signal-soft); border-radius: 0 var(--radius) var(--radius) 0;
}
.note-body hr{ border: none; border-top: 1px solid var(--line); margin: 2.2rem 0; }
.note-body code{
  font-family: var(--font-mono); font-size: 0.87em; background: var(--accent-soft);
  color: var(--ink); padding: 0.12em 0.4em; border-radius: var(--radius);
}
.note-body pre{
  background: var(--code-bg); color: var(--code-fg); padding: 1rem 1.1rem;
  border-radius: var(--radius); overflow-x: auto; margin: 1.2rem 0; font-size: 0.86rem;
  box-shadow: var(--shadow);
}
.note-body pre code{ background: none; padding: 0; color: inherit; }
.note-body table{ width: 100%; border-collapse: collapse; margin: 1.2rem 0; font-size: 0.92rem; }
.note-body th, .note-body td{ border: 1px solid var(--line); padding: 0.5em 0.7em; text-align: left; }
.note-body th{ font-family: var(--font-mono); font-size: 0.76rem; color: var(--ink-soft);
  text-transform: uppercase; letter-spacing: 0.04em; }
.note-body img{ max-width: 100%; border-radius: var(--radius); }
.note-body .katex-display{ margin: 1.4rem 0; overflow-x: auto; overflow-y: hidden; padding-bottom: 2px; }
.note-body .katex{ font-size: 1.04em; }
.heading-anchor{
  opacity: 0; margin-left: 0.5em; color: var(--ink-faint); text-decoration: none;
  font-family: var(--font-mono); font-size: 0.8em;
}
.note-body h2:hover .heading-anchor, .note-body h3:hover .heading-anchor{ opacity: 1; }

.note-footer{
  margin-top: 3.5rem; padding-top: 1.3rem; border-top: 1px solid var(--line);
  font-family: var(--font-mono); font-size: 0.78rem; color: var(--ink-faint);
  display: flex; justify-content: space-between; flex-wrap: wrap; gap: 0.6rem;
}

.loading, .error{
  font-family: var(--font-mono); font-size: 0.86rem; color: var(--ink-faint);
  padding: 3rem 0.1rem;
}
.error{ color: #b5482f; }