:root {
  --bg: #302e2b;
  --panel: #262522;
  --panel2: #21201d;
  --line: #3d3a36;
  --text: #ebe9e6;
  --muted: #a39f9a;
  --green: #81b64c;
  --green-dark: #6a9a3c;
  --light-sq: #eeeed2;
  --dark-sq: #769656;
  --hl: rgba(255, 241, 110, 0.55);
  --sq: 64px;

  --c-book: #8a8681;
  --c-brilliant: #1baca6;
  --c-best: #26c2a3;
  --c-great: #5a9bd5;
  --c-excellent: #96bc4b;
  --c-good: #a3ad8e;
  --c-inaccuracy: #f7c631;
  --c-mistake: #ffa459;
  --c-blunder: #fa412d;
}

* { box-sizing: border-box; }

/* Must beat the display values set on .loading/.app/.promo/.gameover/etc. */
[hidden] { display: none !important; }

html, body {
  margin: 0;
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font: 14px/1.45 "Segoe UI", system-ui, -apple-system, Roboto, Helvetica, Arial, sans-serif;
}

/* ---------- loading ---------- */
.loading {
  position: fixed; inset: 0; z-index: 999;
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  gap: 18px; background: var(--bg);
}
.spinner {
  width: 42px; height: 42px; border-radius: 50%;
  border: 4px solid var(--line); border-top-color: var(--green);
  animation: spin 0.9s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }
.loading p { color: var(--muted); margin: 0; }

/* ---------- layout ---------- */
.app { display: flex; flex-direction: column; min-height: 100%; }

.topbar {
  display: flex; align-items: center; justify-content: space-between;
  gap: 16px; flex-wrap: wrap;
  padding: 10px 18px; background: var(--panel2);
  border-bottom: 1px solid var(--line);
}
.brand { font-size: 17px; font-weight: 700; letter-spacing: .2px; }
.brand .logo { color: var(--green); font-size: 22px; vertical-align: -2px; }

.controls { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; }
.ctl { display: flex; align-items: center; gap: 6px; font-size: 12px; color: var(--muted); }
.ctl select {
  background: var(--panel); color: var(--text); border: 1px solid var(--line);
  border-radius: 5px; padding: 5px 7px; font-size: 12px;
}

.btn {
  background: var(--panel); color: var(--text); border: 1px solid var(--line);
  border-radius: 6px; padding: 7px 13px; font-size: 13px; font-weight: 600; cursor: pointer;
}
.btn:hover { background: #33312d; }
.btn-primary { background: var(--green); border-color: var(--green); color: #1b2410; }
.btn-primary:hover { background: var(--green-dark); border-color: var(--green-dark); }
.btn:disabled { opacity: .45; cursor: default; }

.main {
  display: flex; gap: 22px; align-items: flex-start;
  padding: 20px; flex: 1; flex-wrap: wrap;
}

.board-col { display: flex; flex-direction: column; gap: 8px; }

/* ---------- player strips (captured pieces + material) ---------- */
.player {
  display: flex; align-items: center; gap: 10px;
  margin-left: 32px; min-height: 40px;
}
.pavatar {
  width: 34px; height: 34px; border-radius: 5px; flex: none;
  display: flex; align-items: center; justify-content: center;
  font-size: 22px; line-height: 1;
}
.pavatar.w { background: #e8e6e1; color: #4a4a4a; }
.pavatar.b { background: #4a4743; color: #16150f; }
.pinfo { display: flex; flex-direction: column; gap: 1px; min-width: 0; }
.pname { font-size: 14px; font-weight: 700; }
.ptaken { display: flex; align-items: center; gap: 4px; min-height: 15px; }
.takengroup { display: inline-flex; align-items: center; margin-right: 5px; }
.taken { width: 17px; height: 17px; display: block; margin-right: -7px; opacity: .85; }
.taken.txt { font-size: 15px; width: auto; height: auto; margin-right: -4px; }
.padv { font-size: 12px; font-weight: 700; color: var(--muted); margin-left: 4px; }
.pclock {
  margin-left: auto; font-size: 20px; font-weight: 700;
  font-variant-numeric: tabular-nums; color: var(--muted);
  background: var(--panel2); border-radius: 5px; padding: 4px 12px;
}
.pclock.active { color: var(--text); background: #3b4a2b; }
.pclock.low { color: #fa412d; }
.board-row { display: flex; gap: 10px; align-items: stretch; }

/* ---------- eval bar ---------- */
.evalbar {
  position: relative; width: 22px; border-radius: 4px; overflow: hidden;
  background: #3a3734; flex: none;
}
.evalbar-fill {
  position: absolute; left: 0; right: 0; bottom: 0; height: 50%;
  background: #f0f0ee; transition: height .35s ease;
}
.evalbar-label {
  position: absolute; left: 0; right: 0; top: 4px;
  text-align: center; font-size: 9px; font-weight: 700; color: var(--muted);
}

/* ---------- board ---------- */
.board-wrap { position: relative; flex: none; }
.board {
  display: grid;
  grid-template-columns: repeat(8, var(--sq));
  grid-template-rows: repeat(8, var(--sq));
  border-radius: 5px; overflow: hidden;
  box-shadow: 0 8px 30px rgba(0,0,0,.45);
  touch-action: none; user-select: none;
}
.sq { position: relative; display: flex; align-items: center; justify-content: center; }
.sq::after { transition: background .12s ease; }
.sq.light { background: var(--light-sq); }
.sq.dark  { background: var(--dark-sq); }
.sq.hl::after {
  content: ""; position: absolute; inset: 0; background: var(--hl); pointer-events: none;
}
.sq.sel::after {
  content: ""; position: absolute; inset: 0; background: rgba(255,241,110,.65); pointer-events: none;
}
.sq.check::before {
  content: ""; position: absolute; inset: 0; pointer-events: none;
  background: radial-gradient(circle, rgba(255,60,40,.95) 12%, rgba(255,60,40,.5) 45%, transparent 72%);
}
.coord {
  position: absolute; font-size: 9px; font-weight: 700; opacity: .65; pointer-events: none;
}
.coord.file { right: 3px; bottom: 1px; }
.coord.rank { left: 3px; top: 1px; }
.sq.light .coord { color: var(--dark-sq); }
.sq.dark .coord  { color: var(--light-sq); }

.piece {
  width: 94%; height: 94%; display: block;
  cursor: grab; pointer-events: none;
  position: relative; z-index: 2;
  will-change: transform;
  filter: drop-shadow(0 1px 1px rgba(0,0,0,.28));
}
/* Text fallback if the sprite can't be fetched. */
.piece.txt {
  font-size: calc(var(--sq) * 0.82); line-height: 1; text-align: center;
  width: auto; height: auto; filter: none;
}
.piece.txt.w { color: #fff; -webkit-text-stroke: calc(var(--sq) * 0.022) #2c2c2c; }
.piece.txt.b { color: #2b2825; -webkit-text-stroke: calc(var(--sq) * 0.014) #000; }

.dot {
  position: absolute; width: 30%; height: 30%; border-radius: 50%;
  background: rgba(20,20,20,.28); pointer-events: none; z-index: 1;
}
.ring {
  position: absolute; inset: 4%; border-radius: 50%;
  border: calc(var(--sq) * 0.08) solid rgba(20,20,20,.25); pointer-events: none; z-index: 1;
}

.floating {
  position: fixed; z-index: 500; pointer-events: none;
  width: calc(var(--sq) * 1.08); height: calc(var(--sq) * 1.08);
  transform: translate(-50%, -50%);
  line-height: 1; text-align: center;
  filter: drop-shadow(0 6px 10px rgba(0,0,0,.45));
}

.arrows { position: absolute; inset: 0; pointer-events: none; z-index: 3; }

/* ---------- promotion + game over ---------- */
.promo {
  position: absolute; inset: 0; z-index: 400;
  background: rgba(0,0,0,.55);
  display: flex; align-items: center; justify-content: center; gap: 8px;
}
.promo button {
  width: calc(var(--sq) * 1.1); height: calc(var(--sq) * 1.1);
  display: flex; align-items: center; justify-content: center; padding: 4%;
  background: #f4f4f0; border: 2px solid var(--green); border-radius: 8px;
  cursor: pointer; color: #2b2825; font-size: calc(var(--sq) * 0.7); line-height: 1;
}
.promopiece { width: 100%; height: 100%; display: block; }
.promo button:hover { background: #fff; }

.gameover {
  position: absolute; inset: 0; z-index: 400;
  background: rgba(0,0,0,.62);
  display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 12px;
  border-radius: 5px; text-align: center; padding: 20px;
}
.gameover h2 { margin: 0; font-size: 26px; }
.gameover p { margin: 0; color: var(--muted); max-width: 340px; }

.status {
  background: var(--panel); border: 1px solid var(--line); border-radius: 6px;
  padding: 9px 12px; color: var(--muted); font-size: 13px;
}
.status b { color: var(--text); }

/* ---------- panel ---------- */
.panel {
  flex: 1 1 330px; min-width: 300px; max-width: 460px;
  background: var(--panel); border: 1px solid var(--line); border-radius: 8px;
  display: flex; flex-direction: column; overflow: hidden;
  align-self: stretch;
}
.tabs { display: flex; border-bottom: 1px solid var(--line); }
.tab {
  flex: 1; background: none; border: none; color: var(--muted);
  padding: 11px 8px; font-size: 13px; font-weight: 600; cursor: pointer;
  border-bottom: 2px solid transparent;
}
.tab.active { color: var(--text); border-bottom-color: var(--green); background: var(--panel2); }
.tabpane { padding: 12px; overflow-y: auto; flex: 1; }

.accrow { display: flex; gap: 8px; margin-bottom: 12px; }
.accbox {
  flex: 1; background: var(--panel2); border-radius: 6px; padding: 8px 10px;
  display: flex; flex-direction: column; gap: 2px;
}
.acclabel { font-size: 10px; text-transform: uppercase; letter-spacing: .6px; color: var(--muted); }
.accvalue { font-size: 21px; font-weight: 700; color: var(--green); }
.accvalue.small { font-size: 17px; color: var(--text); }

/* ---------- review card ---------- */
.review {
  background: var(--panel2); border: 1px solid var(--line);
  border-radius: 8px; padding: 12px; margin-bottom: 12px;
}
.review-head { display: flex; gap: 11px; align-items: center; margin-bottom: 10px; }
.badge {
  width: 34px; height: 34px; border-radius: 7px; flex: none;
  display: flex; align-items: center; justify-content: center;
  font-size: 18px; font-weight: 700; color: #16180f;
}
.review-title { font-size: 15px; font-weight: 700; }
.review-sub { font-size: 12px; color: var(--muted); }
.review-sub b { color: var(--text); }

.best-label {
  font-size: 10px; text-transform: uppercase; letter-spacing: .6px;
  color: var(--muted); margin: 10px 0 5px;
}
.best-list { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 4px; }
.best-list li {
  display: flex; align-items: baseline; gap: 8px;
  background: var(--panel); border-radius: 5px; padding: 6px 9px; font-size: 13px;
}
.best-list .mv { font-weight: 700; min-width: 52px; }
.best-list .ev { color: var(--green); font-variant-numeric: tabular-nums; min-width: 46px; }
.best-list .ln { color: var(--muted); font-size: 11px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

.reason {
  background: var(--panel); border-left: 3px solid var(--green);
  border-radius: 4px; padding: 7px 10px; font-size: 12px; color: var(--text); margin-top: 8px;
}

.evalgraph {
  width: 100%; height: 66px; display: block;
  background: #34312d; border-radius: 5px; margin-bottom: 10px;
}

.chips { display: flex; flex-wrap: wrap; gap: 6px; }
.chip {
  display: inline-flex; align-items: center; gap: 5px;
  background: var(--panel); border-radius: 20px; padding: 3px 9px; font-size: 11px;
}
.chip i { width: 8px; height: 8px; border-radius: 2px; display: inline-block; }

.reason.answer { border-left-color: var(--c-best); }
.hidden-answer {
  background: var(--panel); border: 1px dashed var(--line); border-radius: 5px;
  padding: 9px 11px; font-size: 12px; color: var(--muted); margin-top: 10px;
}

/* ---------- settings ---------- */
.setrow {
  display: flex; align-items: center; gap: 12px;
  padding: 10px 0; border-bottom: 1px solid var(--line);
}
.setlabel { flex: 1; font-size: 13px; display: flex; flex-direction: column; gap: 2px; }
.setnote { font-size: 11px; color: var(--muted); }
.setrow select {
  background: var(--panel2); color: var(--text); border: 1px solid var(--line);
  border-radius: 5px; padding: 5px 7px; font-size: 12px;
}
.setrow input[type="checkbox"] { width: 17px; height: 17px; accent-color: var(--green); }

.review-actions { display: flex; gap: 8px; margin-top: 12px; }
.review-actions .btn { flex: 1; }

/* ---------- move list ---------- */
.movelist { display: flex; flex-direction: column; }
.mrow { display: grid; grid-template-columns: 34px 1fr 1fr; align-items: center; font-size: 13px; }
.mrow:nth-child(odd) { background: var(--panel2); }
.mno { color: var(--muted); font-size: 11px; padding: 5px 6px; }
.mcell { padding: 5px 7px; display: flex; align-items: center; gap: 5px; }
.mcell .san { font-weight: 600; }
.tag { width: 9px; height: 9px; border-radius: 2px; flex: none; }

/* ---------- progress ---------- */
.ptitle { font-size: 12px; text-transform: uppercase; letter-spacing: .6px; color: var(--muted); margin: 0 0 8px; }
.gamerow {
  display: grid; grid-template-columns: 1fr auto auto; gap: 10px; align-items: center;
  padding: 8px 10px; background: var(--panel2); border-radius: 6px; margin-bottom: 6px; font-size: 13px;
}
.gamerow .date { color: var(--muted); font-size: 11px; }
.gamerow .acc { font-weight: 700; color: var(--green); font-variant-numeric: tabular-nums; }
.bars { display: flex; align-items: flex-end; gap: 4px; height: 90px; margin: 4px 0 16px; }
.bars .bar { flex: 1; background: var(--green); border-radius: 3px 3px 0 0; min-height: 3px; }
.empty { color: var(--muted); font-size: 13px; padding: 16px 4px; }

/* ---------- touch + safe areas ---------- */
.board, .player, .topbar { -webkit-user-select: none; -webkit-touch-callout: none; }
.btn, .tab, select, input { touch-action: manipulation; }
.topbar { padding-top: calc(10px + env(safe-area-inset-top, 0px)); }
.main { padding-bottom: calc(20px + env(safe-area-inset-bottom, 0px)); }

/* ---------- tablet ---------- */
@media (max-width: 900px) {
  .main { flex-direction: column; align-items: center; }
  .panel { max-width: none; width: 100%; }
}

/* ---------- phone ---------- */
@media (max-width: 700px) {
  .main { padding: 8px; gap: 10px; align-items: stretch; }
  .board-col { gap: 6px; align-items: center; }

  /* The board fills the width; everything else scrolls under it. */
  .board { box-shadow: 0 4px 16px rgba(0,0,0,.4); }
  .board-row { gap: 6px; }
  .evalbar { width: 18px; }
  .evalbar-label { font-size: 8px; }

  .player { margin-left: 0; width: 100%; min-height: 34px; gap: 8px; }
  .pavatar { width: 28px; height: 28px; font-size: 18px; }
  .pname { font-size: 13px; }
  .pclock { font-size: 17px; padding: 3px 10px; }

  /* Topbar: no wordmark, and everything visible on two rows — nothing to scroll
     for, because New game must never be off-screen. */
  .topbar { padding: 8px 8px; padding-top: calc(8px + env(safe-area-inset-top, 0px)); gap: 6px; }
  .brand { display: none; }
  .controls { width: 100%; flex-wrap: wrap; gap: 6px; overflow: visible; }
  .ctl { flex: 1 1 28%; font-size: 0; gap: 0; min-width: 0; }   /* label hidden, control kept */
  .ctl select { width: 100%; font-size: 12px; padding: 7px 6px; }
  .btn { flex: 1 1 45%; padding: 9px 10px; font-size: 13px; white-space: nowrap; }

  .panel { width: 100%; border-radius: 6px; }
  .tabpane { padding: 10px; }
  .tab { padding: 10px 4px; font-size: 12px; }
  .accvalue { font-size: 19px; }
  .status { font-size: 12px; padding: 8px 10px; width: 100%; }
  .review-actions { flex-direction: column; }
  .best-list .ln { display: none; }                   /* lines don't fit; evals still do */
  .gamerow { grid-template-columns: 1fr auto; }
}

/* ---------- boot failure ---------- */
.booterr {
  max-width: 420px; text-align: center; display: flex; flex-direction: column;
  align-items: center; gap: 12px; padding: 0 20px;
}
.booterr h2 { margin: 0; font-size: 20px; }
.booterr p { margin: 0; color: var(--muted); font-size: 13px; line-height: 1.6; }
.booterr .why {
  background: var(--panel2); border-left: 3px solid var(--c-blunder);
  border-radius: 4px; padding: 8px 11px; color: var(--text);
  font-family: ui-monospace, Menlo, monospace; font-size: 12px; text-align: left; width: 100%;
}
.booterr code { background: var(--panel2); padding: 1px 5px; border-radius: 3px; }

/* ---------- weakness report ---------- */
.wrow {
  display: flex; flex-direction: column; gap: 4px;
  padding: 9px 0; border-bottom: 1px solid var(--line);
}
.wtop { display: flex; align-items: baseline; justify-content: space-between; }
.wlabel { font-size: 13px; font-weight: 600; }
.wlabel em {
  font-style: normal; font-size: 10px; text-transform: uppercase; letter-spacing: .5px;
  color: var(--c-mistake); background: rgba(255,164,89,.12);
  border-radius: 3px; padding: 1px 5px; margin-left: 7px;
}
.wval { font-size: 15px; font-weight: 700; color: var(--green); font-variant-numeric: tabular-nums; }
.wbar { display: block; height: 5px; background: var(--panel2); border-radius: 3px; overflow: hidden; }
.wbar i { display: block; height: 100%; background: var(--green); border-radius: 3px; }
.wrow.weak .wbar i { background: var(--c-mistake); }
.wrow.weak .wval { color: var(--c-mistake); }
.wsub { font-size: 11px; color: var(--muted); }
.wnone { font-size: 11px; color: var(--muted); }
.wfoot { font-size: 11px; color: var(--muted); margin: 10px 0 0; }
.gamerow.retired { opacity: .5; }
.setnote.ok  { color: var(--green); }
.setnote.bad { color: var(--c-blunder); }

/* ---------- opening trainer ---------- */
.trainbar { height: 5px; background: var(--panel); border-radius: 3px; overflow: hidden; margin: 8px 0 4px; }
.trainbar i { display: block; height: 100%; background: var(--green); transition: width .25s ease; }
.reason.bad-move { border-left-color: var(--c-mistake); }
.perfect {
  font-size: 10px; text-transform: uppercase; letter-spacing: .5px;
  color: var(--c-best); background: rgba(38,194,163,.13);
  border-radius: 3px; padding: 1px 5px; margin-left: 6px;
}
.wbar i.theme { background: var(--c-mistake); }

/* ---------- walkthrough ---------- */
.lessonstep {
  background: var(--panel); border-radius: 5px; padding: 9px 11px;
  font-size: 13px; margin-top: 8px; line-height: 1.5;
}
.lessonstep.finished { border-left: 3px solid var(--c-best); }
.lessonstep .who {
  display: block; font-size: 10px; text-transform: uppercase; letter-spacing: .6px;
  color: var(--muted); margin-bottom: 2px;
}
.rowbtns { display: flex; gap: 6px; }
.setrow input[type="text"] {
  background: var(--panel2); color: var(--text); border: 1px solid var(--line);
  border-radius: 5px; padding: 6px 9px; font-size: 12px; width: 140px;
}
.best-list li.pickable { cursor: pointer; transition: background .12s ease; }
.best-list li.pickable:hover { background: #33312d; }
.best-list li.pickable::after {
  content: "›"; margin-left: auto; color: var(--muted); font-size: 16px; line-height: 1;
}

/* ---------- puzzle categories ---------- */
.catgrid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 8px; }
.catcard {
  display: flex; flex-direction: column; gap: 2px; text-align: left;
  background: var(--panel2); border: 1px solid var(--line); border-radius: 7px;
  padding: 10px 12px; cursor: pointer; color: var(--text);
}
.catcard:hover { background: #33312d; border-color: var(--green); }
.catname { font-size: 13px; font-weight: 600; }
.catmeta { font-size: 11px; color: var(--muted); }
.muted-sm { font-size: 11px; color: var(--muted); font-weight: 400; }
@media (max-width: 700px) { .catgrid { grid-template-columns: 1fr 1fr; } }