:root {
  --bg: #f4f1ea;
  --panel: #ffffff;
  --ink: #23201c;
  --muted: #7d766c;
  --faint: #b3aca1;
  --rule: #e2ddd3;
  --accent: #4a7c59;
  --accent-dark: #3c6549;
  --variation: #8a5a2b;
  --hilite: #dcead0;
  --danger: #a8402c;
  --radius: 8px;
  --shadow: 0 1px 2px rgba(0,0,0,.05), 0 6px 18px rgba(0,0,0,.05);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 14px/1.5 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}

h2 { font-size: 15px; margin: 0; }
.dim { color: var(--muted); }
.small { font-size: 12px; }
.hidden { display: none !important; }

/* ---------------------------------------------------------------- topbar */

.topbar {
  display: flex; align-items: center; gap: 20px;
  padding: 12px 20px;
  background: var(--panel);
  border-bottom: 1px solid var(--rule);
  flex-wrap: wrap;
}

.brand { font-weight: 650; font-size: 16px; display: flex; align-items: center; gap: 9px; }
.brand .mark {
  font-size: 20px; color: var(--accent);
  background: var(--hilite); border-radius: 6px;
  width: 30px; height: 30px; display: grid; place-items: center;
}

.loader { display: flex; gap: 8px; flex: 1; min-width: 320px; }
.loader input {
  flex: 1; padding: 8px 12px; font-size: 14px;
  border: 1px solid var(--rule); border-radius: var(--radius);
  background: #fdfcfa; color: var(--ink);
}
.loader input:focus { outline: 2px solid var(--accent); border-color: transparent; }

.token-row {
  display: flex; gap: 12px; align-items: center; flex-wrap: wrap;
  padding: 10px 20px; background: #fffdf7;
  border-bottom: 1px solid var(--rule);
}
.token-row input {
  padding: 7px 11px; min-width: 340px;
  border: 1px solid var(--rule); border-radius: var(--radius);
}
.hint { font-size: 12px; color: var(--muted); }
.hint a { color: var(--accent); }

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

button, .ghost {
  font: inherit; cursor: pointer;
  padding: 8px 14px; border-radius: var(--radius);
  border: 1px solid var(--rule); background: var(--panel); color: var(--ink);
  transition: background .12s, border-color .12s;
}
button:hover { background: #f6f3ec; }
button.primary {
  background: var(--accent); border-color: var(--accent); color: #fff; font-weight: 600;
}
button.primary:hover { background: var(--accent-dark); }
button:disabled { opacity: .45; cursor: default; }
.ghost { background: transparent; }
.block { display: block; width: 100%; text-align: center; margin-top: 8px; text-decoration: none; }
.small-btn { padding: 4px 10px; font-size: 12px; }

.status {
  margin: 14px 20px; padding: 11px 15px;
  border-radius: var(--radius); background: #fff4f0;
  border: 1px solid #f0d5cc; color: var(--danger);
  white-space: pre-wrap; font-size: 13px;
}
.status.info { background: #f1f6f2; border-color: #d5e5d9; color: var(--accent-dark); }

/* ------------------------------------------------------------------ grid */

.app {
  display: grid;
  grid-template-columns: 250px minmax(420px, 1fr) minmax(320px, 460px);
  gap: 16px; padding: 16px 20px 28px;
  align-items: start;
}
@media (max-width: 1150px) {
  .app { grid-template-columns: 1fr; }
}

.chapters, .movepanel, .boardarea {
  background: var(--panel); border: 1px solid var(--rule);
  border-radius: 10px; box-shadow: var(--shadow);
}

.panel-head { padding: 13px 15px; border-bottom: 1px solid var(--rule); }
.panel-head.row { display: flex; justify-content: space-between; align-items: center; }
.panel-foot { padding: 12px 15px; border-top: 1px solid var(--rule); }

/* -------------------------------------------------------------- chapters */

.chapter-list { list-style: none; margin: 0; padding: 6px; max-height: 58vh; overflow-y: auto; }
.chapter-list li {
  padding: 8px 10px; border-radius: 6px; cursor: pointer; font-size: 13px;
  display: flex; justify-content: space-between; gap: 8px;
}
.chapter-list li:hover { background: #f6f3ec; }
.chapter-list li.active { background: var(--hilite); font-weight: 600; }
.chapter-list .count { color: var(--faint); font-size: 11px; flex: none; }

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

.boardarea { padding: 16px; }
.board-wrap { display: flex; gap: 10px; align-items: stretch; justify-content: center; }

.board {
  width: min(60vh, 100%); height: auto; aspect-ratio: 1;
  border-radius: 4px; display: block;
}

.evalbar {
  position: relative; width: 18px; flex: none;
  background: #3a3a3a; border-radius: 3px; overflow: hidden;
  border: 1px solid #cfc9bf;
}
.evalfill {
  position: absolute; left: 0; right: 0; bottom: 0;
  height: 50%; background: #f2f2f2; transition: height .18s ease;
}
.evaltext {
  position: absolute; left: 0; right: 0; top: 2px;
  text-align: center; font-size: 9px; font-weight: 700;
  color: #f0f0f0; text-shadow: 0 0 2px rgba(0,0,0,.6);
}

.controls {
  display: flex; gap: 7px; justify-content: center;
  margin-top: 14px; flex-wrap: wrap;
}
.controls .wide { min-width: 118px; }
/* Chapter jumps sit at the two ends of the row, quieter than the move keys. */
.controls .chapbtn { font-size: 12px; padding: 8px 10px; color: var(--muted); }
.controls .chapbtn:hover:not(:disabled) { color: var(--ink); }

.meta { margin-top: 14px; text-align: center; }
.move-label { font-size: 22px; font-weight: 680; letter-spacing: -.2px; }
/* --side-ink is set per sideline; the brown is the main-line fallback. */
.move-label.variation { color: var(--side-ink, var(--variation)); }

.side-chip { padding: 2px 0; border-radius: 7px; }
.side-chip.side {
  background: var(--side-tint); border-left: 4px solid var(--side-rule);
  padding: 7px 11px;
}
.side-chip.side .dim { color: var(--side-ink); }

.comment {
  margin: 12px auto 0; max-width: 620px; text-align: left;
  padding: 11px 14px; border-left: 3px solid var(--accent);
  background: #f8f6f2; border-radius: 0 6px 6px 0;
  font-size: 13.5px; min-height: 0;
}
.comment:empty { display: none; }

.graph-wrap { margin-top: 16px; }
.evalgraph {
  width: 100%; height: 74px; display: block;
  background: #faf8f4; border: 1px solid var(--rule); border-radius: 6px;
  cursor: crosshair;
}

/* ------------------------------------------------------------ move panel */

.moves {
  padding: 12px 14px; max-height: 74vh; overflow-y: auto;
  font-size: 13.5px; line-height: 1.85;
}

.mv {
  display: inline-block; padding: 1px 4px; border-radius: 4px;
  cursor: pointer; white-space: nowrap;
}
.mv:hover { background: #eef2e8; }
.mv.current { background: var(--hilite); outline: 1px solid var(--accent); font-weight: 700; }
.mv.d0 { font-weight: 600; }
.mv.var { color: var(--side-ink, var(--variation)); font-weight: 400; }

.cmt { color: #5c564d; font-style: italic; font-size: 12.5px; }
.blk { margin: 3px 0; }
.blk[data-depth="1"] { margin-left: 14px; padding-left: 9px; border-left: 2px solid #ece5da; }
.blk[data-depth="2"] { margin-left: 28px; padding-left: 9px; border-left: 2px solid #f0eae0; }
.blk[data-depth="3"], .blk[data-depth="4"], .blk[data-depth="5"] {
  margin-left: 42px; padding-left: 9px; border-left: 2px solid #f3eee6;
}
/* One colour per sideline: the wash groups its moves, the bar bounds them.
   Must follow the [data-depth] rules -- same specificity, source order wins. */
.blk.side {
  background: var(--side-tint);
  border-left: 3px solid var(--side-rule);
  border-radius: 0 5px 5px 0;
  padding: 2px 6px 2px 9px;
}
.stag {
  font-size: 10px; font-weight: 700; letter-spacing: .2px;
  color: var(--side-ink); opacity: .8; margin-right: 1px;
}
.dot { color: var(--faint); font-size: 10px; vertical-align: super; }

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

.home {
  max-width: 1000px; margin: 22px auto 40px; padding: 0 18px;
}
.home-head { margin-bottom: 12px; }
.home-head h2 { font-size: 17px; }
.home-head p { margin: 3px 0 0; }

.home-section { margin-top: 16px; }
.home-section h3 {
  font-size: 11px; font-weight: 700; letter-spacing: .08em;
  text-transform: uppercase; color: var(--faint);
  margin: 0 0 7px; padding-bottom: 5px; border-bottom: 1px solid var(--rule);
}

.home-list { display: block; }
.card-row {
  display: grid; gap: 9px;
  grid-template-columns: repeat(auto-fill, minmax(268px, 1fr));
}

.study-card {
  display: flex; flex-direction: column; gap: 4px; align-items: flex-start;
  text-align: left; width: 100%; cursor: pointer;
  padding: 11px 13px; border: 1px solid var(--rule); border-radius: var(--radius);
  background: var(--panel); box-shadow: var(--shadow); font: inherit;
  transition: border-color .12s ease, transform .12s ease;
}
.study-card:hover {
  border-color: var(--accent); transform: translateY(-1px);
}
.card-name {
  font-size: 14px; font-weight: 620; color: var(--ink); line-height: 1.35;
}
.card-meta { font-size: 11.5px; color: var(--muted); }
.badge {
  display: inline-block; margin-left: 6px; padding: 0 5px;
  border-radius: 4px; background: var(--hilite); color: var(--accent-dark);
  font-size: 10px; font-weight: 700; letter-spacing: .03em;
}

.home-empty {
  padding: 18px; border: 1px dashed var(--rule); border-radius: var(--radius);
  color: var(--muted); background: var(--panel);
}

/* ---------------------------------------------------------------- dialog */

.dialog {
  position: fixed; inset: 0; background: rgba(30,26,22,.42);
  display: grid; place-items: center; z-index: 40; padding: 20px;
}
.dialog-card {
  background: var(--panel); border-radius: 12px; padding: 22px 24px;
  width: min(560px, 100%); box-shadow: 0 18px 50px rgba(0,0,0,.22);
  max-height: 90vh; overflow-y: auto;
}
.dialog-card h2 { margin-bottom: 16px; font-size: 17px; }

.field { display: block; margin-bottom: 14px; }
.field span { display: block; font-size: 12px; color: var(--muted); margin-bottom: 5px; }
.field select {
  width: 100%; padding: 8px 10px; font: inherit;
  border: 1px solid var(--rule); border-radius: var(--radius); background: #fdfcfa;
}

.checks { display: grid; gap: 7px; margin: 14px 0 18px; font-size: 13px; }
.checks label { display: flex; gap: 8px; align-items: center; cursor: pointer; }

.dialog-actions { display: flex; gap: 9px; justify-content: flex-end; }
.note { font-size: 12px; color: var(--muted); margin: 8px 0 0; }
.note.warn { color: #97622a; }

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

.board-box {
  position: relative;
  width: min(60vh, 100%);
  aspect-ratio: 1;
}
.board-box .board { width: 100%; height: 100%; }

.squares {
  position: absolute; inset: 0;
  display: grid;
  grid-template-columns: repeat(8, 1fr);
  grid-template-rows: repeat(8, 1fr);
}
.sq { position: relative; cursor: pointer; }
.sq.pickable::after {
  content: ""; position: absolute; inset: 0;
  box-shadow: inset 0 0 0 3px rgba(74, 124, 89, .55);
  border-radius: 2px;
}
.sq.selected::after {
  content: ""; position: absolute; inset: 0;
  background: rgba(74, 124, 89, .34);
}
.sq.target::after {
  content: ""; position: absolute;
  left: 50%; top: 50%; width: 30%; height: 30%;
  transform: translate(-50%, -50%);
  background: rgba(20, 20, 20, .28);
  border-radius: 50%;
}
.sq.target.capture::after {
  width: 86%; height: 86%; background: none;
  box-shadow: inset 0 0 0 5px rgba(20, 20, 20, .26);
  border-radius: 50%;
}

.free-banner {
  display: flex; align-items: center; gap: 12px; justify-content: center;
  margin-bottom: 12px; padding: 8px 14px;
  background: #fff6e8; border: 1px solid #f0dcbe;
  border-radius: var(--radius); font-size: 13px; color: #8a5a2b;
}

.engine-line { margin-top: 4px; font-variant-numeric: tabular-nums; }

/* --------------------------------------------------- hover preview */

.preview {
  position: fixed; z-index: 60; pointer-events: none;
  padding: 5px; background: var(--panel);
  border: 1px solid var(--rule); border-radius: 8px;
  box-shadow: 0 10px 28px rgba(0,0,0,.18);
}
.preview img { display: block; width: 208px; height: 208px; }

.mv.playable { border-bottom: 1px dotted transparent; }