/* Opening Trainer. Club-room palette: baize green, brass, ivory. */

/* Dancing Script, SIL Open Font License 1.1 (fonts/OFL.txt). Used only for the academy name. */
@font-face {
    font-family: "Dancing Script";
    src: url("../fonts/dancing-script-600.woff2") format("woff2");
    font-weight: 600;
    font-style: normal;
    font-display: swap;
}

:root {
    --felt: #0f1c17;
    --felt-raised: #15271f;
    --felt-high: #1d3429;
    --rule: #2b4538;
    --ink: #ebe5d4;
    --ink-dim: #a5af9f;
    --brass: #c9a34e;
    --brass-ink: #19130a;
    --flag: #e3654f;
    --sage: #8cc489;
    --sq-light: #e6d1a7;
    --sq-dark: #a77b4f;
    --serif: "Iowan Old Style", "Palatino Linotype", Palatino, "Book Antiqua", "URW Palladio L", P052, Georgia, serif;
    --sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    --topbar: 56px;
    --gutter: 16px;
    color-scheme: dark;
}

:root[data-theme="light"] {
    --felt: #eef1ec;
    --felt-raised: #ffffff;
    --felt-high: #e0e7de;
    --rule: #c6d1c4;
    --ink: #15241d;
    --ink-dim: #4b5b52;
    --brass: #8a6517;
    --brass-ink: #fffaf0;
    --flag: #b23b28;
    --sage: #2e7838;
    color-scheme: light;
}

*, *::before, *::after { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
    margin: 0;
    background: var(--felt);
    color: var(--ink);
    font-family: var(--sans);
    font-size: 1rem;
    line-height: 1.5;
    min-height: 100dvh;
}

a { color: inherit; }
h1, h2, h3 { font-family: var(--serif); font-weight: 600; line-height: 1.2; margin: 0; }
p { margin: 0; }
button, input, select, textarea { font: inherit; color: inherit; }

:focus-visible { outline: 2px solid var(--brass); outline-offset: 2px; }

.visually-hidden {
    position: absolute !important; width: 1px; height: 1px; padding: 0; margin: -1px;
    overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0;
}
.skip { position: absolute; left: -999px; top: 8px; z-index: 10; background: var(--brass); color: var(--brass-ink); padding: 8px 12px; }
.skip:focus { left: 8px; }
.muted { color: var(--ink-dim); }
.noscript { padding: 24px; }

/* ---------- top bar ---------- */

.topbar {
    position: sticky; top: 0; z-index: 5;
    height: var(--topbar);
    display: flex; align-items: center; justify-content: space-between; gap: 12px;
    padding: 0 var(--gutter);
    padding-left: max(var(--gutter), env(safe-area-inset-left));
    padding-right: max(var(--gutter), env(safe-area-inset-right));
    background: var(--felt);
    border-bottom: 1px solid var(--rule);
}
.brand {
    display: inline-flex; align-items: center; gap: 10px; white-space: nowrap;
    font-family: var(--serif); font-size: 1.1875rem; font-weight: 600; text-decoration: none;
}
.brand-mark { width: 18px; height: 18px; color: var(--brass); }
.topnav { display: flex; gap: 4px; }
.topnav a {
    display: inline-flex; align-items: center; gap: 6px; min-height: 44px; padding: 0 12px;
    text-decoration: none; color: var(--ink-dim); border-radius: 6px;
}
.topnav a:hover { color: var(--ink); background: var(--felt-raised); }
.badge {
    min-width: 22px; height: 22px; padding: 0 6px; border-radius: 11px;
    background: var(--brass); color: var(--brass-ink);
    font-size: 0.8125rem; font-weight: 700; display: inline-flex; align-items: center; justify-content: center;
}
[hidden] { display: none !important; }

@media (max-width: 420px) {
    .topbar { --gutter: 12px; }
    .brand { font-size: 1.0625rem; }
    .topnav a { padding: 0 8px; }
}

main { outline: none; }
.view { padding: 24px var(--gutter) 48px; max-width: 1280px; margin: 0 auto; }

/* ---------- buttons ---------- */

.btn {
    display: inline-flex; align-items: center; justify-content: center; gap: 8px;
    min-height: 44px; padding: 0 16px;
    border: 1px solid var(--rule); border-radius: 6px;
    background: var(--felt-raised); color: var(--ink);
    font-family: var(--sans); font-size: 0.9375rem; font-weight: 500;
    text-decoration: none; cursor: pointer; white-space: nowrap;
}
.btn:hover { border-color: var(--brass); }
.btn:disabled { opacity: 0.4; cursor: default; border-color: var(--rule); }
.btn-primary { background: var(--brass); border-color: var(--brass); color: var(--brass-ink); font-weight: 600; }
.btn-primary:hover { filter: brightness(1.08); }
.btn-small { min-height: 40px; padding: 0 12px; font-size: 0.875rem; }
.btn-icon { width: 52px; padding: 0; font-family: var(--serif); font-size: 1.5rem; line-height: 1; }
.btn-big { flex-direction: column; align-items: flex-start; gap: 0; min-height: 60px; padding: 8px 20px; font-size: 1.0625rem; }
.btn-detail { font-size: 0.8125rem; font-weight: 500; opacity: 0.8; }
.btn-danger { color: var(--flag); border-color: var(--flag); background: transparent; }

/* ---------- board ---------- */

.board-frame { width: 100%; aspect-ratio: 1; touch-action: none; }
.cm-chessboard.ot .board .square.white { fill: var(--sq-light); }
.cm-chessboard.ot .board .square.black { fill: var(--sq-dark); }
.cm-chessboard.ot .board .border { fill: var(--sq-dark); stroke: none; }
.cm-chessboard.ot .coordinates { pointer-events: none; user-select: none; }
.cm-chessboard.ot .coordinates .coordinate { font-family: var(--sans); font-size: 6.5px; font-weight: 600; }
.cm-chessboard.ot .coordinates .coordinate.black { fill: var(--sq-light); }
.cm-chessboard.ot .coordinates .coordinate.white { fill: var(--sq-dark); }

.cm-chessboard .markers .marker.mk-last { fill: #d9b44a; opacity: 0.42; }
.cm-chessboard .markers .marker.mk-input { stroke: #f1d27a; stroke-width: 2px; opacity: 0.9; }
.cm-chessboard .markers .marker.mk-hint { stroke: #3d8d4b; stroke-width: 4px; opacity: 0.85; }
.cm-chessboard .markers .marker.mk-wrong { fill: #d6402a; opacity: 0.55; }
.cm-chessboard .markers .marker.mk-green { stroke: #2f8a43; stroke-width: 4px; opacity: 0.85; }
.cm-chessboard .markers .marker.mk-red { stroke: #c93a26; stroke-width: 4px; opacity: 0.85; }
.cm-chessboard .markers .marker.mk-yellow { stroke: #d9a520; stroke-width: 4px; opacity: 0.9; }
.cm-chessboard .markers .marker.mk-blue { stroke: #2e6fbf; stroke-width: 4px; opacity: 0.85; }
.cm-chessboard .ar-green .arrow-head { fill: #2f8a43; }
.cm-chessboard .ar-green .arrow-line { stroke: #2f8a43; stroke-linecap: round; opacity: 0.8; }
.cm-chessboard .ar-red .arrow-head { fill: #c93a26; }
.cm-chessboard .ar-red .arrow-line { stroke: #c93a26; stroke-linecap: round; opacity: 0.8; }
.cm-chessboard .ar-yellow .arrow-head { fill: #d9a520; }
.cm-chessboard .ar-yellow .arrow-line { stroke: #d9a520; stroke-linecap: round; opacity: 0.85; }
.cm-chessboard .ar-blue .arrow-head { fill: #2e6fbf; }
.cm-chessboard .ar-blue .arrow-line { stroke: #2e6fbf; stroke-linecap: round; opacity: 0.8; }
.cm-chessboard .ar-answer .arrow-head { fill: #2f8a43; }
.cm-chessboard .ar-answer .arrow-line { stroke: #2f8a43; stroke-linecap: round; opacity: 0.9; }

.shake { animation: shake 0.32s ease-in-out; }
@keyframes shake {
    20% { transform: translateX(-6px); }
    40% { transform: translateX(5px); }
    60% { transform: translateX(-4px); }
    80% { transform: translateX(2px); }
}
@media (prefers-reduced-motion: reduce) {
    .shake { animation: none; outline: 3px solid var(--flag); outline-offset: -3px; }
}

.meter { display: inline-block; width: 56px; height: 4px; border-radius: 2px; background: var(--rule); overflow: hidden; }
.meter > span { display: block; height: 100%; background: var(--brass); }
.meter-wide { width: 100%; max-width: 420px; height: 6px; border-radius: 3px; }

/* ---------- home ---------- */

.home {
    display: grid;
    grid-template-columns: minmax(0, 1fr);
    grid-template-areas: "intro" "board" "index";
    gap: 24px;
}
.home-intro { grid-area: intro; max-width: 34rem; }
.home-brand { margin: 0 0 18px; display: grid; gap: 0; }
.home-app { font-family: var(--serif); font-size: 1.125rem; color: var(--ink-dim); }
.academy {
    font-family: "Dancing Script", "Segoe Script", cursive;
    font-weight: 600;
    font-size: clamp(1.875rem, 1.4rem + 1.9vw, 2.625rem);
    line-height: 1.15;
    color: var(--brass);
}
.home-intro h1 { font-size: clamp(1.75rem, 1.1rem + 2.6vw, 2.75rem); letter-spacing: -0.01em; }
.lede { margin-top: 12px; font-family: var(--serif); font-size: 1.1875rem; line-height: 1.55; color: var(--ink-dim); }
.review-strip {
    margin-top: 20px; display: flex; flex-wrap: wrap; align-items: center; gap: 12px 16px;
    padding: 12px 16px; border: 1px solid var(--brass); border-radius: 8px;
}
.home-board { grid-area: board; width: min(100%, 280px); justify-self: center; }
.home-board .board-frame { touch-action: auto; } /* display only: let the page scroll over it */
.board-caption { margin-top: 10px; font-family: var(--serif); font-size: 0.9375rem; color: var(--ink-dim); text-align: center; }
.home-index { grid-area: index; }

.index { list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--rule); }
.opening {
    padding: 20px 0 20px 16px;
    border-bottom: 1px solid var(--rule);
    border-left: 3px solid transparent;
    outline: none;
}
.opening.is-shown { border-left-color: var(--brass); }
.op-head { display: flex; align-items: baseline; justify-content: space-between; gap: 12px; }
.op-head h2 { font-size: 1.625rem; }
.eco { font-size: 0.8125rem; color: var(--ink-dim); font-variant-numeric: tabular-nums; }
.op-moves { margin-top: 4px; font-family: var(--serif); font-size: 1.0625rem; }
.op-summary { margin-top: 6px; color: var(--ink-dim); max-width: 38rem; }
.stats-note { margin-top: 24px; max-width: 40rem; font-size: 0.8125rem; color: var(--ink-dim); }
.op-courses { margin-top: 14px; display: flex; flex-wrap: wrap; gap: 8px; }
.course-link {
    display: inline-flex; align-items: center; gap: 10px;
    min-height: 44px; padding: 0 14px;
    border: 1px solid var(--rule); border-radius: 6px; background: var(--felt-raised);
    text-decoration: none; font-weight: 500;
}
a.course-link:hover { border-color: var(--brass); }
.course-link.is-soon { color: var(--ink-dim); background: transparent; border-style: dashed; }
.course-meta { font-size: 0.8125rem; color: var(--ink-dim); }
.side-chip { width: 14px; height: 14px; border-radius: 50%; border: 1.5px solid var(--ink-dim); flex: none; }
.puzzle-chip {
    width: 16px; height: 16px; border-radius: 4px; flex: none;
    display: inline-flex; align-items: center; justify-content: center;
    background: var(--brass); color: var(--brass-ink);
    font-family: var(--serif); font-size: 0.75rem; font-weight: 700; line-height: 1;
}
.course-link.is-soon .puzzle-chip { background: transparent; color: var(--ink-dim); border: 1.5px solid var(--ink-dim); }
.side-chip.white { background: #f4efe2; border-color: #f4efe2; }
.side-chip.black { background: #1b1b1b; border-color: #8a8a8a; }

@media (min-width: 900px) {
    .home {
        grid-template-columns: minmax(300px, 0.9fr) minmax(0, 1.1fr);
        grid-template-areas: "board intro" "board index";
        grid-template-rows: auto 1fr;
        column-gap: 48px;
        align-items: start;
    }
    .home-board { position: sticky; top: calc(var(--topbar) + 24px); width: 100%; max-width: 560px; justify-self: stretch; }
    .board-caption { text-align: left; }
}

/* ---------- course ---------- */

.course { max-width: 1000px; margin: 0 auto; }
.settings { max-width: 860px; margin: 0 auto; }
.backbar { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 20px; }
.btn-back { gap: 6px; padding-left: 10px; max-width: 100%; overflow: hidden; text-overflow: ellipsis; }
.btn-back > span { font-family: var(--serif); font-size: 1.375rem; line-height: 1; margin-top: -3px; }
.tp-head .backbar { margin-bottom: 12px; }
/* Previous / next idea or puzzle, under the back buttons. */
.stepbar { display: flex; justify-content: space-between; gap: 8px; margin-bottom: 12px; }
.btn-step { gap: 6px; min-width: 0; max-width: 50%; }
.btn-step > span[aria-hidden] { font-family: var(--serif); font-size: 1.375rem; line-height: 1; margin-top: -3px; }
.step-text { min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.empty .backbar { margin-bottom: 0; }
.course-head h1 { font-size: clamp(2rem, 1.4rem + 2.4vw, 2.75rem); }
.course-side { margin-top: 6px; font-size: 1.0625rem; }
.course-summary { margin-top: 10px; max-width: 40rem; font-family: var(--serif); font-size: 1.125rem; line-height: 1.6; color: var(--ink-dim); }
.course-actions { margin-top: 24px; display: flex; flex-wrap: wrap; align-items: stretch; gap: 12px; }
.course-stats { margin-top: 20px; display: grid; gap: 8px; color: var(--ink-dim); font-size: 0.9375rem; }

.ideas-list { margin-top: 32px; }
.ideas-list h2 { font-size: 1.3125rem; }
.ideas-list p { margin-top: 4px; font-size: 0.9375rem; }
.ideas-list ol { margin: 12px 0 0; padding-left: 1.5rem; display: grid; gap: 6px; font-family: var(--serif); font-size: 1.125rem; }
.ideas-list a { text-decoration-color: color-mix(in srgb, var(--brass) 60%, transparent); text-underline-offset: 3px; }
.ideas-list a:hover { color: var(--brass); }

/* Puzzle list: a grid of position cards */
.puzzles { max-width: 1000px; margin: 0 auto; }
.puzzle-grid {
    list-style: none; margin: 28px 0 0; padding: 0;
    display: grid; grid-template-columns: repeat(auto-fill, minmax(160px, 1fr)); gap: 16px;
}
.puzzle-card {
    display: grid; gap: 4px; padding: 10px; height: 100%;
    border: 1px solid var(--rule); border-radius: 8px; background: var(--felt-raised);
    text-decoration: none; color: inherit;
}
.puzzle-card .board-frame { touch-action: auto; margin-bottom: 6px; }
.puzzle-card:hover, .puzzle-card:focus-visible { border-color: var(--brass); }
.puzzle-num { font-family: var(--serif); font-size: 1.0625rem; font-weight: 600; }
.puzzle-meta { font-size: 0.8125rem; color: var(--ink-dim); }
.puzzle-status { font-size: 0.8125rem; font-weight: 600; color: var(--ink-dim); }
.puzzle-card.is-solved { border-color: color-mix(in srgb, var(--sage) 70%, transparent); }
.puzzle-card.is-solved .puzzle-status { color: var(--sage); }
.puzzle-card.is-missed { border-color: color-mix(in srgb, var(--flag) 70%, transparent); }
.puzzle-card.is-missed .puzzle-status { color: var(--flag); }
.cm-entry.is-hint .cm-move { color: var(--brass); }
@media (max-width: 420px) {
    .puzzle-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 10px; }
    .puzzle-card { padding: 8px; }
}

.further { margin-top: 40px; padding-top: 16px; border-top: 1px solid var(--rule); }
.extra .further { margin-top: 16px; }
.further h3 { font-family: var(--serif); font-size: 1.125rem; }
.further p { margin-top: 4px; font-size: 0.875rem; }
.further ul { list-style: none; margin: 10px 0 0; padding: 0; display: grid; gap: 8px; }
.further li { display: grid; gap: 1px; }
.further a { font-family: var(--serif); font-size: 1rem; text-underline-offset: 3px; }
.further a:hover { color: var(--brass); }
.further-by { font-size: 0.8125rem; color: var(--ink-dim); }
.commentary p + p { margin-top: 10px; }

/* "Traps": the heading where a course's trap chapters begin. */
.section-title { margin-top: 48px; padding-bottom: 8px; border-bottom: 2px solid currentColor; font-size: 1.75rem; }
.section-title.is-trap { color: var(--flag); }
.section-title + .chapter { margin-top: 24px; }

/* Each chapter: board on the left, heading and lines on the right. */
.chapter {
    margin-top: 40px;
    display: grid;
    grid-template-columns: 112px minmax(0, 1fr);
    grid-template-areas: "board head" "lines lines";
    column-gap: 16px;
    align-items: start;
}
.chapter-board { grid-area: board; display: block; text-decoration: none; color: inherit; }
.chapter-board .board-frame { touch-action: auto; }
a.chapter-board:hover .board-frame, a.chapter-board:focus-visible .board-frame { outline: 2px solid var(--brass); outline-offset: 3px; }
a.chapter-board:focus-visible { outline: none; }
.chapter-board-caption { display: block; margin-top: 6px; font-family: var(--serif); font-size: 0.875rem; color: var(--ink-dim); text-align: center; }
.chapter-head { grid-area: head; }
.chapter .lines { grid-area: lines; }

@media (min-width: 760px) {
    .chapter {
        grid-template-columns: 240px minmax(0, 1fr);
        grid-template-areas: "board head" "board lines";
        column-gap: 32px;
    }
    .chapter-board { position: sticky; top: calc(var(--topbar) + 16px); }
    .chapter-board-caption { font-size: 0.9375rem; }
}
.chapter h2 { font-size: 1.3125rem; display: flex; align-items: baseline; gap: 10px; }
.tag {
    font-family: var(--sans); font-size: 0.75rem; font-weight: 600;
    padding: 2px 8px; border-radius: 4px; border: 1px solid var(--flag); color: var(--flag);
}
.chapter-intro { margin-top: 6px; max-width: 40rem; color: var(--ink-dim); font-family: var(--serif); font-size: 1.0625rem; }
.chapter-share { margin-top: 6px; display: flex; align-items: center; gap: 10px; font-size: 0.875rem; color: var(--ink-dim); font-variant-numeric: tabular-nums; }
.share-bar { flex: none; width: 96px; height: 6px; border-radius: 3px; background: var(--felt-high); overflow: hidden; }
.share-bar > span { display: block; height: 100%; min-width: 2px; background: var(--brass); }
.chapter-trap .share-bar > span { background: var(--flag); }
.lines { list-style: none; margin: 12px 0 0; padding: 0; border-top: 1px solid var(--rule); }
.line-row {
    display: flex; align-items: center; justify-content: space-between; gap: 12px;
    padding: 12px 0; border-bottom: 1px solid var(--rule);
}
.line-name { display: grid; gap: 2px; min-width: 0; }
.line-name > span:first-child {
    font-family: var(--serif); font-size: 1.125rem;
    display: flex; align-items: center; gap: 10px;
}
.line-name > span:first-child::before {
    content: ""; width: 10px; height: 10px; border-radius: 50%; flex: none;
    border: 1.5px solid var(--ink-dim);
}
.line-row.is-learning .line-name > span:first-child::before { border-color: var(--brass); background: linear-gradient(90deg, var(--brass) 50%, transparent 50%); }
.line-row.is-review .line-name > span:first-child::before { border-color: var(--brass); background: var(--brass); }
.line-row.is-known .line-name > span:first-child::before { border-color: var(--sage); background: var(--sage); }
.line-row.is-due .line-name > span:first-child::before { box-shadow: 0 0 0 3px color-mix(in srgb, var(--brass) 35%, transparent); }
.line-meta { font-size: 0.8125rem; color: var(--ink-dim); padding-left: 20px; }
.line-actions { display: flex; gap: 8px; flex: none; }

/* ---------- trainer ---------- */

.view:has(.trainer) { padding-top: 16px; }
.trainer {
    display: grid;
    grid-template-columns: minmax(0, 1fr);
    grid-template-areas: "head" "board" "controls" "commentary" "extra" "sheet";
    gap: 14px;
}
.trainer-panel { display: contents; }
.tp-head { grid-area: head; }
.trainer-board { grid-area: board; }
.controls { grid-area: controls; }
.commentary { grid-area: commentary; }
.extra { grid-area: extra; }
.scoresheet { grid-area: sheet; }

.trainer-board .board-frame { margin: 0 auto; max-width: 640px; }
.tp-title { margin-top: 4px; font-size: 1.5rem; }
.tp-sub { margin-top: 2px; font-family: var(--serif); color: var(--ink-dim); font-size: 1.0625rem; }

.controls { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 10px; }
.nav-buttons, .more-buttons { display: flex; flex-wrap: wrap; gap: 8px; }
.prompt { font-weight: 600; }

.commentary { min-height: 5.5rem; }
.cm-entry + .cm-entry { margin-top: 12px; padding-top: 12px; border-top: 1px solid var(--rule); }
.cm-move { font-size: 1.25rem; display: flex; flex-wrap: wrap; align-items: baseline; gap: 4px 10px; }
.cm-who { font-family: var(--sans); font-size: 0.8125rem; font-weight: 500; color: var(--ink-dim); }
.commentary p { margin-top: 6px; font-family: var(--serif); font-size: 1.0625rem; line-height: 1.6; max-width: 38rem; }
.cm-entry.is-wrong .cm-move { color: var(--flag); }
.cm-entry.is-you .cm-who, .cm-entry.is-fixed .cm-who { color: var(--sage); }
.cm-entry.is-alt .cm-move { color: var(--brass); }

.banner { padding: 10px 12px; border-left: 3px solid var(--brass); background: var(--felt-raised); display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 8px; }
.alts { margin-top: 12px; }
.alts h3 { font-family: var(--sans); font-size: 0.875rem; font-weight: 600; color: var(--ink-dim); }
.alts ul { list-style: none; margin: 6px 0 0; padding: 0; display: grid; gap: 6px; }
.alts li { display: flex; align-items: baseline; gap: 10px; }
.alt-move {
    flex: none; min-height: 36px; padding: 0 10px; border-radius: 6px;
    border: 1px solid var(--rule); background: var(--felt-raised); cursor: pointer;
    font-family: var(--serif); font-size: 1.0625rem;
}
.alt-move:hover { border-color: var(--brass); }
.alt-note { font-size: 0.875rem; color: var(--ink-dim); }
.alt-row { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 6px; }
.puzzle-action { display: flex; flex-wrap: wrap; align-items: center; gap: 10px; }
.extra .banner + .banner, .extra .result + .banner { margin-top: 10px; }

.result { padding: 12px 14px; border: 1px solid var(--rule); border-radius: 8px; background: var(--felt-raised); }
.result h2 { font-size: 1.25rem; }
.result p { margin-top: 4px; }
.result-score { font-variant-numeric: tabular-nums; }
.result.is-clean { border-color: var(--sage); }
.result.is-failed { border-color: var(--flag); }

.scoresheet {
    border: 1px solid var(--rule); border-radius: 8px; background: var(--felt-raised);
    padding: 6px 0; overflow-y: auto;
    /* Fifteen moves fit before the sheet scrolls: each row is 1.5rem of text, 12px of padding and a 1px rule. */
    max-height: calc(15 * (1.5rem + 13px) + 12px);
    font-family: var(--serif); font-variant-numeric: tabular-nums;
}
.sheet-row { display: grid; grid-template-columns: 3rem 1fr 1fr; align-items: stretch; }
.sheet-row + .sheet-row { border-top: 1px solid color-mix(in srgb, var(--rule) 60%, transparent); }
.sheet-num { padding: 0 0 0 12px; color: var(--ink-dim); font-size: 0.9375rem; align-self: center; }
.sheet-move {
    display: block; width: 100%; text-align: left; padding: 6px 10px; line-height: 1.5rem;
    font-family: var(--serif); font-size: 1.0625rem; background: none; border: 0; border-radius: 4px; color: inherit;
}
button.sheet-move { cursor: pointer; }
button.sheet-move:hover { background: var(--felt-high); }
.sheet-move.is-current { background: var(--brass); color: var(--brass-ink); }
.sheet-move.is-missed { text-decoration: underline wavy var(--flag); text-underline-offset: 4px; }
/* Puzzle follow-up: moves after the last one the solver had to find. */
.sheet-move.is-after:not(.is-current) { color: var(--ink-dim); font-style: italic; }
.sheet-empty { padding: 6px 12px; color: var(--ink-dim); }

@media (min-width: 900px) and (min-aspect-ratio: 1/1) {
    .trainer {
        grid-template-columns: minmax(0, 1fr) minmax(320px, 400px);
        grid-template-areas: none;
        column-gap: 32px;
        align-items: start;
    }
    .trainer-board { grid-area: auto; }
    .trainer-board .board-frame { width: min(100%, calc(100dvh - var(--topbar) - 48px)); max-width: none; }
    .trainer-panel {
        display: flex; flex-direction: column; gap: 16px;
        max-height: calc(100dvh - var(--topbar) - 32px);
        position: sticky; top: calc(var(--topbar) + 16px);
        overflow-y: auto; overscroll-behavior: contain;
    }
    /* Long notes scroll inside the panel instead of being squeezed; the buttons stay in view. */
    .trainer-panel > * { flex-shrink: 0; }
    .tp-head, .controls, .commentary, .extra, .scoresheet { grid-area: auto; }
    .scoresheet { order: 1; max-height: calc(15 * (1.5rem + 7px) + 12px); }
    .sheet-move { padding-top: 3px; padding-bottom: 3px; }
    .controls { position: sticky; bottom: 0; z-index: 1; padding: 10px 0 2px; background: var(--felt); }
    .tp-head { order: 0; }
    .commentary { order: 2; }
    .extra { order: 3; }
    .controls { order: 4; }
}

/* ---------- empty, settings ---------- */

.empty { max-width: 34rem; margin: 48px auto; display: grid; gap: 14px; justify-items: start; }
.empty h1 { font-size: 2rem; }

.settings h1 { font-size: 2.25rem; }
.settings-group { margin-top: 32px; padding-top: 20px; border-top: 1px solid var(--rule); display: grid; gap: 14px; }
.settings-group h2 { font-size: 1.3125rem; }
.settings-group h3 { font-size: 1.0625rem; margin-top: 6px; }
.field { border: 0; margin: 0; padding: 0; display: grid; gap: 8px; }
.field legend { padding: 0; margin-bottom: 8px; font-weight: 600; }
label.field { font-weight: 600; }
label.field select { font-weight: 400; max-width: 10rem; min-height: 44px; padding: 0 10px; border: 1px solid var(--rule); border-radius: 6px; background: var(--felt-raised); }
.segmented { display: flex; flex-wrap: wrap; gap: 8px; }
.segmented label { position: relative; }
.segmented input { position: absolute; opacity: 0; inset: 0; margin: 0; cursor: pointer; }
.segmented span {
    display: inline-flex; align-items: center; min-height: 44px; padding: 0 14px;
    border: 1px solid var(--rule); border-radius: 6px; background: var(--felt-raised);
}
.segmented input:checked + span { border-color: var(--brass); box-shadow: inset 0 0 0 1px var(--brass); font-weight: 600; }
.segmented input:focus-visible + span { outline: 2px solid var(--brass); outline-offset: 2px; }
.row { display: flex; flex-wrap: wrap; gap: 8px; }
textarea.code {
    width: 100%; padding: 10px; border: 1px solid var(--rule); border-radius: 6px; background: var(--felt-raised);
    font-family: ui-monospace, "Cascadia Mono", Consolas, monospace; font-size: 0.8125rem; resize: vertical;
}
.form-status:empty { display: none; }
.form-status { padding: 8px 12px; border-left: 3px solid var(--brass); background: var(--felt-raised); }
.credits { margin: 0; padding-left: 20px; color: var(--ink-dim); display: grid; gap: 4px; }
.about p { max-width: 40rem; }