/* SPDX-License-Identifier: GPL-3.0-or-later - the TBOSS project page and manual (scripts/build_site.py). */
:root {
  --bg: #ffffff; --bg-soft: #f6f7fa; --bg-hero: #0b0c12; --text: #1c1f2a; --muted: #5d6476; --line: #e3e6ee;
  --accent: #5446e6; --accent-soft: #eeecfe; --accent-text: #ffffff;
  --try: #0d7d55; --try-bg: #eaf7f1; --why: #3c5a99; --why-bg: #eef3fb; --not: #9a5b00; --not-bg: #fdf5e6;
  --code-bg: #f1f2f6; --shadow: 0 1px 2px rgba(20, 24, 40, .06), 0 4px 16px rgba(20, 24, 40, .06);
  --rainbow: linear-gradient(90deg, #ff3d6e, #ff9a1f, #ffd93d, #3ad686, #2ec4ff, #5b6cff, #b14dff);
  --header: 56px;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0f1117; --bg-soft: #161922; --text: #e6e8ef; --muted: #9ba3b6; --line: #282d3a;
    --accent: #9a90ff; --accent-soft: #221f3f; --accent-text: #0f1117;
    --try: #57d3a4; --try-bg: #10251d; --why: #93b2f0; --why-bg: #141d2e; --not: #f0b452; --not-bg: #2a2012;
    --code-bg: #1d2130; --shadow: 0 1px 2px rgba(0, 0, 0, .3), 0 4px 16px rgba(0, 0, 0, .25);
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #0f1117; --bg-soft: #161922; --text: #e6e8ef; --muted: #9ba3b6; --line: #282d3a;
  --accent: #9a90ff; --accent-soft: #221f3f; --accent-text: #0f1117;
  --try: #57d3a4; --try-bg: #10251d; --why: #93b2f0; --why-bg: #141d2e; --not: #f0b452; --not-bg: #2a2012;
  --code-bg: #1d2130; --shadow: 0 1px 2px rgba(0, 0, 0, .3), 0 4px 16px rgba(0, 0, 0, .25);
  color-scheme: dark;
}

* { box-sizing: border-box; }
html { scroll-padding-top: calc(var(--header) + 16px); -webkit-text-size-adjust: 100%; }
body {
  margin: 0; background: var(--bg); color: var(--text);
  font: 16.5px/1.65 Inter, system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  font-feature-settings: "cv11", "ss01"; -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); text-decoration-thickness: 1px; text-underline-offset: 2px; }
a:hover { text-decoration-thickness: 2px; }
img { max-width: 100%; }
code, pre { font-family: ui-monospace, "Cascadia Mono", "SF Mono", Menlo, Consolas, monospace; font-size: .88em; }
code { background: var(--code-bg); padding: .12em .38em; border-radius: 5px; }
pre { background: var(--code-bg); padding: 14px 16px; border-radius: 10px; overflow-x: auto; line-height: 1.45; }
pre code { background: none; padding: 0; font-size: .86em; }

/* --- header ------------------------------------------------------------------------------- */
.site-header {
  position: sticky; top: 0; z-index: 20; height: var(--header);
  display: flex; align-items: center; gap: 20px; padding: 0 20px;
  background: color-mix(in srgb, var(--bg) 88%, transparent); backdrop-filter: saturate(1.4) blur(10px);
  border-bottom: 1px solid var(--line);
}
.site-header::before { content: ""; position: absolute; left: 0; right: 0; top: 0; height: 3px; background: var(--rainbow); }
.brand { display: flex; align-items: center; gap: 10px; color: var(--text); text-decoration: none; font-weight: 700; letter-spacing: .02em; }
.brand img { width: 30px; height: 30px; border-radius: 7px; flex: none; }
.site-nav { display: flex; gap: 4px; margin-left: auto; align-items: center; }
.site-nav a { color: var(--muted); text-decoration: none; font-weight: 500; font-size: 15px; padding: 6px 10px; border-radius: 8px; }
.site-nav a:hover, .site-nav a[aria-current="page"] { color: var(--text); background: var(--bg-soft); }
.icon-button {
  border: 1px solid var(--line); background: var(--bg); color: var(--muted); border-radius: 8px;
  width: 36px; height: 36px; display: inline-grid; place-items: center; cursor: pointer; font: inherit;
}
.icon-button:hover { color: var(--text); }
.icon-button svg { width: 18px; height: 18px; }
.contents-button { display: none; width: auto; padding: 0 12px; gap: 6px; font-size: 14px; font-weight: 600; }

/* --- buttons ------------------------------------------------------------------------------ */
.button {
  display: inline-flex; align-items: center; gap: 8px; padding: 11px 18px; border-radius: 10px;
  font-weight: 600; font-size: 15.5px; text-decoration: none; border: 1px solid transparent;
}
.button.primary { background: var(--accent); color: var(--accent-text); }
.button.primary:hover { filter: brightness(1.08); }
.button.ghost { color: #f2f3f8; border-color: rgba(255, 255, 255, .28); }
.button.ghost:hover { background: rgba(255, 255, 255, .08); }

/* --- project page --------------------------------------------------------------------------- */
.hero { background: var(--bg-hero); color: #eef0f6; }
.hero-inner {
  max-width: 1080px; margin: 0 auto; padding: 64px 24px 72px;
  display: grid; grid-template-columns: 300px 1fr; gap: 48px; align-items: center;
}
.hero img { width: 300px; height: auto; border-radius: 22px; box-shadow: 0 20px 60px rgba(90, 80, 255, .25); }
.hero h1 { font-size: clamp(30px, 4.2vw, 46px); line-height: 1.12; margin: 0 0 16px; letter-spacing: -.02em; }
.hero h1 .glow { background: var(--rainbow); -webkit-background-clip: text; background-clip: text; color: transparent; }
.hero p { font-size: 18.5px; color: #b9bfd0; margin: 0 0 26px; max-width: 34em; }
.hero .actions { display: flex; flex-wrap: wrap; gap: 12px; }
.hero .button.primary { background: #ffffff; color: #12131a; }
.hero .meta { margin-top: 22px; font-size: 14px; color: #8d94a8; }
.hero .meta strong { color: #d7dbe7; font-weight: 600; }

.section { max-width: 1080px; margin: 0 auto; padding: 56px 24px; }
.section > h2 { font-size: 28px; letter-spacing: -.015em; margin: 0 0 8px; }
.section > .lead { color: var(--muted); margin: 0 0 28px; max-width: 46em; }
.notice {
  max-width: 1080px; margin: 32px auto 0; padding: 0 24px;
}
.notice p {
  margin: 0; padding: 14px 18px; border-radius: 12px; background: var(--bg-soft); border: 1px solid var(--line);
  color: var(--muted); font-size: 15px;
}
.notice strong { color: var(--text); }
.notice.thanks { margin: 0 auto 48px; }
/* The donation card under the community notice: easy to find, still optional */
.donate { max-width: 1080px; margin: 12px auto 0; padding: 0 24px; }
.donate-card {
  position: relative; display: flex; align-items: center; gap: 16px 18px; /* text to button = button to edge */
  padding: 16px 18px 16px 22px; border-radius: 12px; overflow: hidden; background: var(--accent-soft);
  border: 1px solid color-mix(in srgb, var(--accent) 30%, transparent);
}
.donate-card::before { content: ""; position: absolute; left: 0; top: 0; bottom: 0; width: 5px;
  background: linear-gradient(180deg, #ff3d6e, #ff9a1f, #ffd93d, #3ad686, #2ec4ff, #5b6cff, #b14dff); }
.donate-card p { flex: 1; margin: 0; font-size: 15px; color: var(--muted); text-align: justify; } /* ends 18px from the button */
.donate-card strong { color: var(--text); }
.donate-card .button { flex: none; }
.features { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 16px; }
.feature {
  display: block; padding: 20px; border-radius: 14px; background: var(--bg); border: 1px solid var(--line);
  color: var(--text); text-decoration: none; transition: border-color .15s, box-shadow .15s, transform .15s;
}
.feature:hover { border-color: var(--accent); box-shadow: var(--shadow); transform: translateY(-1px); }
.feature h3 { margin: 0 0 6px; font-size: 17px; }
.feature p { margin: 0; color: var(--muted); font-size: 15px; line-height: 1.55; }
.feature .dot { display: block; width: 28px; height: 4px; border-radius: 2px; margin-bottom: 14px; }
.band { background: var(--bg-soft); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.news > :not(h2) { max-width: 46em; }
.news ul { padding-left: 1.2em; }
.news li { margin: 6px 0; }
.more { font-weight: 600; text-decoration: none; }
.steps-home { counter-reset: step; list-style: none; padding: 0; margin: 0; display: grid; gap: 14px; max-width: 760px; }
.steps-home li { counter-increment: step; position: relative; padding-left: 48px; }
.steps-home li::before {
  content: counter(step); position: absolute; left: 0; top: 0; width: 32px; height: 32px; border-radius: 50%;
  display: grid; place-items: center; font-weight: 700; font-size: 15px; background: var(--accent-soft); color: var(--accent);
}
.site-footer { border-top: 1px solid var(--line); color: var(--muted); font-size: 14px; }
.site-footer .inner { max-width: 1080px; margin: 0 auto; padding: 28px 24px 40px; display: flex; flex-wrap: wrap; gap: 8px 24px; }
.site-footer a { color: var(--muted); }

/* --- manual --------------------------------------------------------------------------------- */
.layout { display: grid; grid-template-columns: 290px minmax(0, 1fr); max-width: 1240px; margin: 0 auto; }
.sidebar {
  position: sticky; top: var(--header); height: calc(100vh - var(--header)); overflow-y: auto;
  border-right: 1px solid var(--line); padding: 20px 14px 40px 20px; font-size: 14.5px; overscroll-behavior: contain;
}
.toc-filter {
  width: 100%; padding: 8px 12px; border-radius: 9px; border: 1px solid var(--line); background: var(--bg-soft);
  color: var(--text); font: inherit; margin-bottom: 14px;
}
.toc-filter:focus { outline: 2px solid var(--accent); outline-offset: -1px; }
.toc ul { list-style: none; margin: 0; padding: 0; }
.toc li { margin: 0; }
.toc a {
  display: block; padding: 4px 10px; border-radius: 7px; color: var(--muted); text-decoration: none; line-height: 1.4;
}
.toc a:hover { color: var(--text); background: var(--bg-soft); }
.toc a.active { color: var(--accent); background: var(--accent-soft); font-weight: 600; }
.toc ul ul { margin: 2px 0 6px 10px; padding-left: 8px; border-left: 1px solid var(--line); display: none; font-size: 13.5px; }
.toc li.open > ul, .toc.filtering ul ul { display: block; }
.toc .hidden { display: none; }
.toc .tag, h2 .tag, h3 .tag { font-size: .68em; }

.manual { padding: 32px 48px 120px; min-width: 0; }
.manual article { max-width: 780px; }
.manual h1 { font-size: 38px; letter-spacing: -.02em; line-height: 1.15; margin: 8px 0 18px; }
.manual h2 {
  font-size: 27px; letter-spacing: -.015em; line-height: 1.25; margin: 64px 0 14px; padding-top: 28px;
  border-top: 1px solid var(--line);
}
.manual h3 { font-size: 20.5px; line-height: 1.3; margin: 40px 0 10px; }
.manual h4 { font-size: 17px; margin: 28px 0 8px; }
.manual h2, .manual h3, .manual h4 { position: relative; }
.anchor { position: absolute; left: -1em; width: 1em; color: var(--muted); opacity: 0; text-decoration: none; font-weight: 400; }
h2:hover .anchor, h3:hover .anchor, h4:hover .anchor, .anchor:focus { opacity: .7; }
.tag {
  display: inline-block; vertical-align: middle; margin-left: 8px; padding: 2px 8px; border-radius: 99px;
  font-size: 12px; font-weight: 600; letter-spacing: .02em; text-transform: lowercase;
  background: var(--accent-soft); color: var(--accent); line-height: 1.5;
}
.manual p, .manual li { margin: 0 0 14px; }
.manual li > div > p:last-child, .manual li > p:last-child { margin-bottom: 4px; }
.manual ul, .manual ol { padding-left: 1.4em; margin: 0 0 16px; }
.manual li { margin-bottom: 6px; }
.manual ol.steps { list-style: none; padding-left: 0; }
.manual ol.steps > li { display: grid; grid-template-columns: 2.6em minmax(0, 1fr); align-items: baseline; }
.manual ol.steps > li > .n { font-weight: 700; color: var(--accent); font-variant-numeric: tabular-nums; }
.manual hr { border: 0; border-top: 1px solid var(--line); margin: 32px 0; }
.manual blockquote {
  margin: 0 0 16px; padding: 12px 16px; border-left: 3px solid var(--accent); background: var(--accent-soft); border-radius: 0 10px 10px 0;
}
.manual blockquote p:last-child { margin: 0; }
.table { overflow-x: auto; margin: 0 0 20px; border: 1px solid var(--line); border-radius: 12px; }
.table table { border-collapse: collapse; width: 100%; font-size: 14.5px; line-height: 1.5; }
.table th { text-align: left; font-weight: 600; background: var(--bg-soft); }
.table th, .table td { padding: 9px 14px; border-bottom: 1px solid var(--line); vertical-align: top; }
.table tr:last-child td { border-bottom: 0; }
.table tbody tr:hover { background: color-mix(in srgb, var(--bg-soft) 60%, transparent); }
.note { margin: 0 0 14px; padding: 12px 16px; border-radius: 12px; border: 1px solid transparent; }
.note p { margin: 0; }
.note strong:first-of-type { margin-right: 2px; }
.note.try { background: var(--try-bg); border-color: color-mix(in srgb, var(--try) 25%, transparent); }
.note.try > p > strong:first-child, .note.try > p > a + strong { color: var(--try); }
.note.why { background: var(--why-bg); border-color: color-mix(in srgb, var(--why) 20%, transparent); }
.note.why > p > strong:first-child { color: var(--why); }
.note.whennot { background: var(--not-bg); border-color: color-mix(in srgb, var(--not) 22%, transparent); }
.note.whennot > p > strong:first-child { color: var(--not); }
.note.why + .note.whennot { margin-top: -6px; }
/* the Roadmap chapter */
.note.request { background: var(--accent-soft); border-color: color-mix(in srgb, var(--accent) 25%, transparent); }
.note.request > p > strong:first-child { color: var(--accent); }
.manual p.group { font-weight: 600; margin: 18px 0 6px; }
.manual ul.roadmap { list-style: none; padding-left: 0; }
.manual ul.roadmap li { position: relative; padding-left: 1.6em; margin-bottom: 8px; }
.manual ul.roadmap li::before { position: absolute; left: 0; top: 0; font-weight: 700; }
.manual ul.planned li::before { content: "\25CB"; color: var(--accent); }
.manual ul.ideas li::before { content: "\2022"; color: var(--muted); left: .3em; }
.manual ul.built li::before { content: "\2713"; color: var(--try); }
.manual ul.built li { color: var(--muted); font-size: 15px; }
details.built { margin: 0 0 16px; border: 1px solid var(--line); border-radius: 12px; padding: 0 16px; }
details.built > summary { cursor: pointer; padding: 12px 0; font-weight: 600; color: var(--accent); }
details.built[open] { padding-bottom: 8px; }
.to-top {
  position: fixed; right: 20px; bottom: 20px; z-index: 15; opacity: 0; pointer-events: none; transition: opacity .2s;
  box-shadow: var(--shadow);
}
.to-top.shown { opacity: 1; pointer-events: auto; }

/* --- narrow screens ---------------------------------------------------------------------- */
@media (max-width: 960px) {
  .layout { grid-template-columns: minmax(0, 1fr); }
  .sidebar {
    position: fixed; z-index: 30; left: 0; top: var(--header); width: min(340px, 88vw); background: var(--bg);
    transform: translateX(-102%); transition: transform .2s; box-shadow: var(--shadow);
  }
  .sidebar.open { transform: none; }
  .contents-button { display: inline-flex; }
  .manual { padding: 24px 16px 96px; }
  .anchor { display: none; }
}
@media (max-width: 760px) {
  .site-header { gap: 10px; padding: 0 12px; }
  .site-nav a.optional { display: none; }
  .hero-inner { grid-template-columns: 1fr; gap: 28px; padding: 40px 16px 48px; text-align: left; }
  .hero img { width: 160px; border-radius: 16px; }
  .section { padding: 40px 16px; }
  .notice, .donate { padding: 0 16px; }
  .donate-card { flex-direction: column; align-items: flex-start; }
  .donate-card p { text-align: left; }
  .manual h1 { font-size: 30px; }
  .manual h2 { font-size: 23px; margin-top: 48px; }
  body { font-size: 16px; }
}
@media (max-width: 420px) { .brand span { display: none; } }
@media (prefers-reduced-motion: reduce) { * { transition: none !important; scroll-behavior: auto !important; } }
/* The manual's pad explorer (webapp/tb-explorer.js): the two halves of pads, stacked, with the chord names and notes. */
.pad-explorer { --pe-off: color-mix(in srgb, var(--text) 8%, var(--bg)); margin: 18px 0 26px; padding: 16px;
  border: 1px solid var(--line); border-radius: 14px; background: var(--bg-soft); }
.pe-controls { display: flex; flex-wrap: wrap; gap: 8px 14px; margin-bottom: 14px; }
.pe-controls label { display: grid; gap: 3px; font-size: 12.5px; color: var(--muted); }
.pe-controls select { font: inherit; font-size: 14px; color: var(--text); background: var(--bg); border: 1px solid var(--line);
  border-radius: 8px; padding: 5px 8px; }
.pe-board { display: grid; gap: 12px; overflow-x: auto; }
.pe-title { font-size: 12.5px; font-weight: 600; color: var(--muted); margin-bottom: 5px; }
.pe-grid { display: grid; grid-template-columns: repeat(12, minmax(46px, 1fr)); gap: 4px; min-width: 588px; }
.pe-pad { aspect-ratio: 1.25; min-width: 0; padding: 2px; border: 0; border-radius: 7px; cursor: pointer; font: inherit;
  background: linear-gradient(180deg, color-mix(in srgb, var(--pad) 92%, #fff), color-mix(in srgb, var(--pad) 78%, #000));
  color: #fff; text-shadow: 0 1px 2px rgba(0, 0, 0, .75); display: grid; place-items: center; }
.pe-pad span { font-size: 11px; font-weight: 600; line-height: 1.1; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; max-width: 100%; }
.pe-pad.picked { outline: 3px solid var(--text); outline-offset: 1px; }
.pe-pad:focus-visible { outline: 3px solid var(--accent); outline-offset: 1px; }
.pe-detail { margin-top: 14px; font-size: 14.5px; }
.pe-what { margin-bottom: 8px; }
.pe-was { color: var(--muted); }
.pe-keys { display: block; width: 100%; height: auto; max-height: 90px; border-radius: 6px; }
.pe-keys .w { fill: #fbfbfd; stroke: #9aa0ad; stroke-width: .6; }
.pe-keys .b { fill: #23252c; }
.pe-keys .on { fill: var(--accent); }
.pe-keys .was { fill: color-mix(in srgb, var(--accent) 30%, #fff); }
.pe-keys .b.was { fill: color-mix(in srgb, var(--accent) 45%, #23252c); }
.pe-keys text { font-size: 7px; fill: #6b7280; text-anchor: middle; }
.pe-note { margin: 10px 0 0; font-size: 13px; color: var(--muted); }
.pe-head { margin-bottom: 12px; font-size: 14.5px; color: var(--muted); }
.pe-head strong { color: var(--text); }