:root {
  --bg: #eef1e3;
  --bg-panel: #f9fbf3;
  --ink: #2b3324;
  --ink-soft: #626f52;
  --line: #d9e0c6;
  --accent: #6f8a4c;
  --accent-soft: #dde6c9;
  --board-light: #eef1e1;
  --board-dark: #8ba06c;
  --board-dark-2: #7c8564;
  --sq-select: #d9c26a;
  --sq-target: rgba(140, 148, 115, 0.55);
  --sq-last: rgba(111, 138, 76, 0.4);
  --blunder: #9c3b3b;
  --blunder-bg: #f6e3e0;
  --mistake: #a4691f;
  --mistake-bg: #f7ead4;
  --inaccuracy: #3d6e8c;
  --inaccuracy-bg: #dfebf1;
  --good: #4c7a4f;
  --shadow: 0 1px 2px rgba(43, 51, 36, 0.06), 0 8px 24px rgba(43, 51, 36, 0.07);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #171c12;
    --bg-panel: #212819;
    --ink: #e9eede;
    --ink-soft: #a3ae90;
    --line: #333f27;
    --accent: #9bbf6e;
    --accent-soft: #2f3b21;
    --board-light: #d9e2c4;
    --board-dark: #5c6b41;
    --board-dark-2: #505c38;
    --sq-select: #b6902f;
    --sq-target: rgba(155, 191, 110, 0.35);
    --sq-last: rgba(155, 191, 110, 0.28);
    --blunder: #e08585;
    --blunder-bg: #3a2422;
    --mistake: #e0ac5f;
    --mistake-bg: #3a2f1c;
    --inaccuracy: #8fc0dd;
    --inaccuracy-bg: #1f2f37;
    --good: #8fce93;
    --shadow: 0 1px 2px rgba(0, 0, 0, 0.3), 0 8px 24px rgba(0, 0, 0, 0.3);
  }
}

* { box-sizing: border-box; -webkit-tap-highlight-color: transparent; }

/* [hidden] has the same specificity as e.g. `.solve-controls{display:flex}`,
   so without this, elements toggled via `.hidden = true` on a flex/grid
   container would silently stay visible. */
[hidden] { display: none !important; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  font-size: 15px;
  line-height: 1.5;
  -webkit-text-size-adjust: 100%;
  overscroll-behavior-y: none;
}

h1, h2, h3 { font-family: 'Fraunces', Georgia, serif; font-weight: 600; margin: 0; }

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px 24px;
  padding: 20px 40px;
  padding-top: max(20px, env(safe-area-inset-top));
  border-bottom: 1px solid var(--line);
  background: var(--bg-panel);
  position: sticky;
  top: 0;
  z-index: 10;
}

.brand { display: flex; align-items: center; gap: 10px; }
.brand-mark { font-size: 24px; color: var(--accent); }
.brand-name { font-family: 'Fraunces', Georgia, serif; font-size: 20px; font-weight: 600; letter-spacing: 0.01em; }

.tabs { display: flex; gap: 4px; }
.tab-btn {
  background: none;
  border: none;
  font-family: inherit;
  font-size: 14px;
  color: var(--ink-soft);
  padding: 8px 16px;
  border-radius: 999px;
  cursor: pointer;
  touch-action: manipulation;
  transition: background 0.15s, color 0.15s;
}
.tab-btn:hover { background: var(--accent-soft); color: var(--ink); }
.tab-btn.active { background: var(--ink); color: var(--bg-panel); }

.nav-select { display: none; }

main { max-width: 1080px; margin: 0 auto; padding: 40px; }

.view { display: none; animation: fadein 0.25s ease; }
.view.active { display: block; }
@keyframes fadein { from { opacity: 0; transform: translateY(4px); } to { opacity: 1; transform: none; } }

.panel {
  background: var(--bg-panel);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 28px;
  margin-bottom: 24px;
  box-shadow: var(--shadow);
}

.intro-panel { background: none; border: none; box-shadow: none; padding: 0 4px 8px; }
.page-title { font-size: 34px; letter-spacing: -0.01em; }
.page-title.small { font-size: 26px; margin-bottom: 20px; }
.page-sub { color: var(--ink-soft); max-width: 560px; margin-top: 10px; }

.field-row { margin-bottom: 18px; }
.field-row label { display: block; font-size: 13px; color: var(--ink-soft); margin-bottom: 6px; }
.field-row-split { display: flex; gap: 20px; }
.field-col { flex: 1; }

input[type="text"], input[type="password"], select, input:not([type]) {
  width: 100%;
  font-family: inherit;
  /* 16px minimum keeps iOS Safari from auto-zooming the page on focus */
  font-size: 16px;
  padding: 10px 12px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--bg);
  color: var(--ink);
}
input:focus, select:focus { outline: 2px solid var(--accent-soft); outline-offset: 1px; }

.actions-row { display: flex; gap: 10px; margin-top: 22px; margin-bottom: 0; }

.btn {
  font-family: inherit;
  font-size: 14px;
  font-weight: 500;
  padding: 10px 20px;
  border-radius: 999px;
  border: 1px solid transparent;
  cursor: pointer;
  touch-action: manipulation;
  transition: transform 0.1s, background 0.15s, opacity 0.15s;
}
.btn:active { transform: scale(0.97); }
.btn-primary { background: var(--ink); color: var(--bg-panel); }
.btn-primary:hover { opacity: 0.85; }
.btn-ghost { background: transparent; border-color: var(--line); color: var(--ink); }
.btn-ghost:hover { background: var(--accent-soft); }
.btn-ghost.danger { color: var(--blunder); border-color: var(--blunder-bg); }
.btn-ghost.danger:hover { background: var(--blunder-bg); }
.btn-ghost.active { background: var(--accent-soft); border-color: transparent; }
.btn.small { padding: 7px 14px; font-size: 13px; }
.btn:disabled { opacity: 0.5; cursor: default; }

.link-btn { background: none; border: none; padding: 0; color: var(--accent); text-decoration: underline; cursor: pointer; font: inherit; }

.progress-panel { }
.progress-line { font-size: 14px; margin-bottom: 8px; }
.progress-line.small { font-size: 12px; color: var(--ink-soft); }
.progress-bar-track { height: 8px; border-radius: 999px; background: var(--line); overflow: hidden; margin-bottom: 10px; }
.progress-bar-fill { height: 100%; background: var(--accent); width: 0%; transition: width 0.2s ease; }
.import-log { list-style: none; margin: 12px 0 0; padding: 0; max-height: 220px; overflow-y: auto; font-size: 13px; color: var(--ink-soft); border-top: 1px solid var(--line); padding-top: 10px; }
.import-log li { padding: 3px 0; }

/* Library */
.library-header { margin-bottom: 8px; }
.library-title-row { display: flex; align-items: baseline; justify-content: space-between; gap: 12px; margin-bottom: 14px; }
.library-title-row .page-title { margin-bottom: 0; }
.filter-bar { display: flex; flex-direction: column; gap: 12px; }
.filter-group { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }
.filter-group select { width: auto; }
.label-filter-group { min-height: 0; }

.chip {
  font-family: inherit;
  font-size: 13px;
  padding: 6px 14px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: var(--bg-panel);
  color: var(--ink-soft);
  cursor: pointer;
  touch-action: manipulation;
  transition: all 0.15s;
}
.chip.active { border-color: transparent; }
.chip-sev.blunder.active { background: var(--blunder-bg); color: var(--blunder); }
.chip-sev.mistake.active { background: var(--mistake-bg); color: var(--mistake); }
.chip-sev.inaccuracy.active { background: var(--inaccuracy-bg); color: var(--inaccuracy); }
.chip-toggle.active { background: var(--accent-soft); color: var(--ink); border-color: transparent; }
.chip-label { background: var(--bg); }
.chip-label.active { background: var(--ink); color: var(--bg-panel); }
.chip-remove { margin-left: 6px; cursor: pointer; opacity: 0.6; }
.chip-remove:hover { opacity: 1; }

.empty-state { text-align: center; padding: 60px 20px; color: var(--ink-soft); }
.session-setup { text-align: left; max-width: 640px; margin: 28px auto 0; }
.session-setup .filter-bar { margin-bottom: 4px; }
.inline-label { font-size: 13px; color: var(--ink-soft); }

.puzzle-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); gap: 18px; margin-top: 20px; }
.puzzle-card {
  background: var(--bg-panel);
  border: 1px solid var(--line);
  border-radius: 14px;
  overflow: hidden;
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
  transition: transform 0.15s;
}
.puzzle-card:hover { transform: translateY(-2px); }
.puzzle-card .board-mount { width: 100%; }
.puzzle-card-body { padding: 14px 16px 16px; display: flex; flex-direction: column; gap: 8px; flex: 1; }
.card-top-row { display: flex; align-items: center; justify-content: space-between; }
.card-status-dot { width: 8px; height: 8px; border-radius: 50%; display: inline-block; margin-right: 6px; }
.card-status-dot.unsolved { background: var(--ink-soft); opacity: 0.4; }
.card-status-dot.solved { background: var(--good); }
.card-status-dot.failed { background: var(--blunder); opacity: 0.7; }
.card-meta { font-size: 12px; color: var(--ink-soft); }
.card-labels { display: flex; flex-wrap: wrap; gap: 5px; }
.card-labels .chip { padding: 3px 9px; font-size: 11px; }
.card-actions { display: flex; gap: 6px; margin-top: auto; padding-top: 8px; }
.star-btn { background: none; border: none; font-size: 16px; cursor: pointer; color: var(--ink-soft); }
.star-btn.active { color: var(--accent); }
.icon-btn { background: none; border: none; cursor: pointer; font-size: 14px; color: var(--ink-soft); padding: 4px; }
.icon-btn:hover { color: var(--blunder); }

.strategy-hint-box {
  margin-top: 14px; padding: 14px 16px; border-radius: 12px;
  background: var(--accent-soft); font-size: 14px; line-height: 1.55;
  white-space: pre-wrap;
}

.load-more-row { display: flex; justify-content: center; margin-top: 24px; }

/* Board */
.board-mount { position: relative; }
.board { position: relative; display: grid; grid-template-columns: repeat(8, 1fr); grid-template-rows: repeat(8, 1fr); width: 100%; aspect-ratio: 1 / 1; border-radius: 6px; overflow: hidden; border: 1px solid var(--line); }
.board-arrow-layer { position: absolute; inset: 0; width: 100%; height: 100%; pointer-events: none; z-index: 5; }
.board-arrow-line { stroke-width: 2.2; stroke-linecap: round; opacity: 0.88; }
.board-arrow-head { opacity: 0.88; }
.board-arrow-line.arrow-last, .board-arrow-head.arrow-last { stroke: var(--accent); fill: var(--accent); }
.board-arrow-line.arrow-wrong, .board-arrow-head.arrow-wrong { stroke: var(--blunder); fill: var(--blunder); }
.board-arrow-line.arrow-threat, .board-arrow-head.arrow-threat { stroke: var(--blunder); fill: var(--blunder); stroke-dasharray: 4 3; }
.board-arrow-line.arrow-best, .board-arrow-head.arrow-best { stroke: var(--good); fill: var(--good); }
.square { position: relative; display: flex; align-items: center; justify-content: center; touch-action: manipulation; user-select: none; }
.square.light { background: var(--board-light); }
.square.dark { background: var(--board-dark); }
.square.last-move { box-shadow: inset 0 0 0 999px var(--sq-last); }
.square.selected { box-shadow: inset 0 0 0 999px var(--sq-select); opacity: 0.9; }
.square.legal-target::after {
  content: '';
  position: absolute;
  width: 28%;
  height: 28%;
  border-radius: 50%;
  background: var(--sq-target);
}
.piece { width: 82%; height: 82%; user-select: none; cursor: pointer; pointer-events: none; filter: drop-shadow(0 1px 1px rgba(0,0,0,0.25)); will-change: transform; }
.coord { position: absolute; font-size: 9px; color: rgba(0,0,0,0.35); font-weight: 600; }
.coord-file { bottom: 2px; right: 3px; }
.coord-rank { top: 2px; left: 3px; }

.board-large { max-width: 480px; }

/* Solve view */
.solve-layout { display: flex; gap: 32px; align-items: flex-start; }
.solve-board-col { flex: 0 0 auto; width: 480px; }
.eval-row { display: flex; align-items: center; gap: 10px; margin-bottom: 10px; }
.eval-bar {
  flex: 1;
  height: 18px;
  border-radius: 6px;
  overflow: hidden;
  border: 1px solid var(--line);
  display: flex;
  flex-direction: row;
  box-shadow: var(--shadow);
}
.eval-bar-white { background: #f4f4ef; flex: 0 0 50%; transition: flex-basis 0.45s ease; }
.eval-bar-black { background: #2b2b28; flex: 1; transition: flex-basis 0.45s ease; }
.eval-label { font-size: 12px; font-weight: 600; color: var(--ink-soft); font-variant-numeric: tabular-nums; white-space: nowrap; min-width: 34px; text-align: right; }
.solve-side-col { flex: 1; min-width: 260px; padding-top: 4px; }
.solve-controls { display: flex; gap: 8px; margin-top: 14px; flex-wrap: wrap; align-items: center; }
.hint-label { min-height: 1.2em; }
#liveControls .btn, #branchControls .btn, #strategyHintControls .btn, #puzzleNavControls .btn { min-width: 148px; text-align: center; }
.move-nav { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 14px; }
.move-nav-chip {
  font-family: inherit;
  font-size: 12px;
  padding: 4px 10px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: var(--bg-panel);
  color: var(--ink-soft);
  cursor: pointer;
}
.move-nav-chip:hover { background: var(--accent-soft); }
.move-nav-chip.active { background: var(--ink); color: var(--bg-panel); border-color: transparent; }
.move-nav-chip.is-live::after { content: ' •'; }

.branch-section { border-top: 1px solid var(--line); margin-top: 18px; padding-top: 16px; }
.branch-section label { display: block; font-size: 13px; color: var(--ink-soft); margin-bottom: 8px; }
.branch-list { display: flex; flex-direction: column; gap: 6px; }
.branch-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 6px 6px 6px 12px;
}
.branch-view-btn {
  background: none;
  border: none;
  font-family: inherit;
  font-size: 13px;
  color: var(--ink);
  cursor: pointer;
  text-align: left;
  flex: 1;
  padding: 4px 0;
}
.branch-view-btn:hover { color: var(--accent); }
.branch-view-btn .branch-line { color: var(--ink-soft); font-size: 12px; display: block; }

.solve-meta { display: flex; align-items: center; gap: 10px; margin-bottom: 14px; }
.solve-meta .chip { cursor: default; }
.solve-prompt { font-size: 18px; font-family: 'Fraunces', Georgia, serif; margin-bottom: 6px; }
.solve-progress { color: var(--ink-soft); font-size: 13px; margin-top: 0; }
.solve-feedback {
  min-height: 24px;
  font-weight: 600;
  margin: 10px 0 0;
  padding: 0 2px;
  transition: color 0.15s;
}
.solve-feedback.correct { color: var(--good); }
.solve-feedback.wrong { color: var(--blunder); }
.solve-feedback.solved { color: var(--good); }
.solve-feedback:empty { min-height: 0; margin: 0; }
.solve-actions-row { display: flex; gap: 8px; margin: 16px 0; }
.label-editor { border-top: 1px solid var(--line); padding-top: 16px; margin-top: 8px; }
.label-editor label { display: block; font-size: 13px; color: var(--ink-soft); margin-bottom: 8px; }
.label-chips { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 10px; min-height: 20px; }
.label-add-row { display: flex; gap: 8px; }
.label-add-row input { flex: 1; }
.label-quickadd { margin-top: 10px; margin-bottom: 0; }
.game-link { margin-top: 20px; font-size: 13px; }
.game-link a { color: var(--accent); }
.muted { color: var(--ink-soft); font-size: 13px; }

@media (max-width: 820px) {
  .solve-layout { flex-direction: column; }
  .solve-board-col { width: 100%; max-width: 480px; }
  main { padding: 24px 18px; }
  .topbar { padding: 16px 20px; }
}

/* Stats */
.stats-summary { display: grid; grid-template-columns: repeat(auto-fit, minmax(140px, 1fr)); gap: 14px; margin-bottom: 24px; }
.stat-card { background: var(--bg-panel); border: 1px solid var(--line); border-radius: 14px; padding: 18px; text-align: center; box-shadow: var(--shadow); }
.stat-num { font-family: 'Fraunces', Georgia, serif; font-size: 30px; display: block; }
.stat-label { font-size: 12px; color: var(--ink-soft); text-transform: uppercase; letter-spacing: 0.04em; }
.stats-columns { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
.panel-title { font-size: 16px; margin-bottom: 14px; }
.bar-row { display: flex; align-items: center; gap: 10px; margin-bottom: 10px; font-size: 13px; }
.bar-row .bar-label { width: 100px; flex-shrink: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.bar-track { flex: 1; height: 8px; background: var(--line); border-radius: 999px; overflow: hidden; }
.bar-fill { height: 100%; }
.bar-row .bar-count { width: 46px; text-align: right; color: var(--ink-soft); flex-shrink: 0; }
.activity-list { list-style: none; padding: 0; margin: 0; }
.activity-list li { display: flex; justify-content: space-between; padding: 8px 0; border-bottom: 1px solid var(--line); font-size: 13px; }
.activity-list li:last-child { border-bottom: none; }
.activity-list li.clickable { cursor: pointer; border-radius: 8px; transition: background 0.15s; }
.activity-list li.clickable:hover { background: var(--accent-soft); padding-left: 6px; padding-right: 6px; }

@media (max-width: 700px) {
  .stats-columns { grid-template-columns: 1fr; }
}

.toast {
  position: fixed;
  bottom: max(24px, calc(env(safe-area-inset-bottom) + 12px));
  left: 50%;
  transform: translateX(-50%);
  background: var(--ink);
  color: var(--bg-panel);
  padding: 12px 20px;
  border-radius: 10px;
  font-size: 14px;
  box-shadow: var(--shadow);
  z-index: 100;
  max-width: calc(100vw - 32px);
  text-align: center;
}
.toast.error { background: var(--blunder); }

/* Phone layout (iPhone 14 Pro and similar: ~390-430px wide) */
@media (max-width: 480px) {
  .topbar {
    padding: 12px 14px;
    padding-top: max(12px, env(safe-area-inset-top));
  }
  .brand-name { font-size: 17px; }
  .brand-mark { font-size: 20px; }
  /* A full row of tab buttons costs a lot of vertical space on a phone —
     swap to a single compact dropdown instead. */
  .tabs { display: none; }
  .nav-select {
    display: block;
    width: auto;
    font-size: 13px;
    font-weight: 600;
    padding: 8px 30px 8px 14px;
    border-radius: 999px;
    background-color: var(--ink);
    color: var(--bg-panel);
    border-color: transparent;
  }

  main { padding: 16px 14px; padding-bottom: max(16px, env(safe-area-inset-bottom)); }

  .page-title { font-size: 26px; }
  .page-title.small { font-size: 21px; margin-bottom: 14px; }
  .page-sub { font-size: 14px; }

  .panel { padding: 18px; border-radius: 14px; }

  .field-row-split { flex-direction: column; gap: 16px; }

  .actions-row { flex-wrap: wrap; }
  .actions-row .btn { flex: 1 1 auto; }

  .library-title-row { flex-wrap: wrap; }

  .filter-group { gap: 6px; }
  .chip { padding: 6px 11px; font-size: 12px; }

  .puzzle-grid { grid-template-columns: 1fr; gap: 14px; }

  .solve-side-col { min-width: 0; }
  .solve-prompt { font-size: 16px; }
  .solve-controls .btn.small { flex: 1 1 auto; }

  .stat-card { padding: 14px; }
  .stat-num { font-size: 24px; }

  .bar-row .bar-label { width: 76px; }
}