:root {
  --bg: #1f2428;
  --panel: #2b3136;
  --panel-2: #353c42;
  --text: #eef1f2;
  --muted: #aeb7bd;
  --accent: #8db35d;
  --accent-2: #c49a42;
  --danger: #d66b5f;
  --light-square: #f0d9b5;
  --dark-square: #b58863;
  --selected: rgba(255, 214, 102, 0.72);
  --target: rgba(141, 179, 93, 0.58);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--text);
  background:
    linear-gradient(135deg, rgba(196, 154, 66, 0.13), transparent 38%),
    linear-gradient(180deg, rgba(141, 179, 93, 0.08), transparent 46%),
    var(--bg);
}

button,
input,
select,
textarea {
  font: inherit;
}

button {
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 6px;
  color: var(--text);
  background: var(--panel-2);
  cursor: pointer;
  min-height: 38px;
  padding: 0 12px;
}

button:hover,
button.active {
  border-color: rgba(141, 179, 93, 0.75);
  background: #405039;
}

.primary {
  background: var(--accent);
  color: #16210f;
  font-weight: 700;
}

.app-shell {
  width: min(1440px, 100%);
  min-height: 100vh;
  margin: 0 auto;
  display: grid;
  grid-template-columns: minmax(520px, 1fr) minmax(360px, 460px);
  gap: 18px;
  padding: 18px;
}

.study-panel,
.side-panel {
  background: rgba(43, 49, 54, 0.94);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 8px;
}

.study-panel {
  display: grid;
  grid-template-rows: auto 1fr;
  min-height: calc(100vh - 36px);
}

.topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  padding: 18px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

h1,
h2,
p {
  margin: 0;
}

h1 {
  font-size: clamp(26px, 4vw, 46px);
  line-height: 1;
}

h2 {
  font-size: 17px;
  margin-bottom: 8px;
}

.topbar p,
.field span,
.status-box,
.commentary,
.move-list,
.opening-card p {
  color: var(--muted);
}

.mode-switch,
.tabs,
.move-tools {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.board-zone {
  display: grid;
  align-content: start;
  justify-items: center;
  gap: 14px;
  padding: 18px;
}

.board-layout {
  width: 100%;
  display: grid;
  grid-template-columns: minmax(180px, 260px) minmax(360px, min(78vh, 760px));
  justify-content: center;
  align-items: start;
  gap: 14px;
}

.board-commentary {
  position: sticky;
  top: 18px;
  align-self: start;
  min-height: 130px;
  margin: 0;
}

.board-commentary p {
  color: var(--text);
  line-height: 1.45;
}

.piece-img,
.piece {
  position: relative;
  z-index: 1;
  transition:
    transform 0.2s ease,
    opacity 0.2s ease;
}

.piece-img.moving,
.piece.moving {
  transform: scale(1.08);
}

.piece-img.arriving {
  opacity: 0;
}

.board-wrap {
  position: relative;
  width: min(78vh, 100%);
  max-width: 760px;
  aspect-ratio: 1;
  box-shadow: 0 24px 70px rgba(0, 0, 0, 0.36);
}

.board {
  display: grid;
  grid-template-columns: repeat(8, 1fr);
  grid-template-rows: repeat(8, 1fr);
  width: 100%;
  height: 100%;
  border-radius: 6px;
  overflow: hidden;
}

.square {
  position: relative;
  display: grid;
  place-items: center;
  border: 0;
  border-radius: 0;
  min-height: 0;
  padding: 0;
  font-size: clamp(28px, 7.4vmin, 72px);
  line-height: 1;
}

.square.light {
  background: var(--light-square);
}

.square.dark {
  background: var(--dark-square);
}

.square.selected::after,
.square.legal::after,
.square.last::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
}

.square.selected::after {
  background: var(--selected);
}

.square.legal::after {
  width: 24%;
  height: 24%;
  place-self: center;
  border-radius: 999px;
  background: rgba(45, 68, 38, 0.45);
}

.square.last::after {
  border: 4px solid rgba(196, 154, 66, 0.55);
}

.piece-img {
  z-index: 1;
  width: 82%;
  height: 82%;
  object-fit: contain;
  user-select: none;
  pointer-events: none;
}

.piece {
  z-index: 1;
  text-shadow: 0 2px 2px rgba(0, 0, 0, 0.35);
}

.black-piece {
  color: #202020;
}

.white-piece {
  color: #fff8ec;
}

.coord {
  position: absolute;
  left: 5px;
  bottom: 4px;
  z-index: 2;
  font-size: 11px;
  font-weight: 700;
  color: rgba(0, 0, 0, 0.68);
  pointer-events: none;
  text-shadow: 0 1px 2px rgba(255, 255, 255, 0.58);
}

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

.moving-piece {
  position: absolute;
  z-index: 5;
  width: 10.25%;
  height: 10.25%;
  object-fit: contain;
  pointer-events: none;
  user-select: none;
  transform: translate(-50%, -50%);
  transition:
    left 240ms ease,
    top 240ms ease;
  filter: drop-shadow(0 10px 14px rgba(0, 0, 0, 0.28));
}

.moving-piece.in-flight {
  left: var(--target-left);
  top: var(--target-top);
}

.arrow {
  position: absolute;
  height: 12px;
  transform-origin: left center;
  background: rgba(214, 107, 95, 0.78);
  border-radius: 999px;
  filter: drop-shadow(0 2px 3px rgba(0, 0, 0, 0.35));
}

.arrow::after {
  content: "";
  position: absolute;
  right: -15px;
  top: -9px;
  border-left: 22px solid rgba(214, 107, 95, 0.78);
  border-top: 15px solid transparent;
  border-bottom: 15px solid transparent;
}

.arrow.pulse {
  animation: pulse-arrow 0.7s ease-in-out infinite alternate;
}

@keyframes pulse-arrow {
  from {
    opacity: 0.45;
  }
  to {
    opacity: 1;
  }
}

.side-panel {
  padding: 14px;
  min-height: calc(100vh - 36px);
  overflow: auto;
}

.tabs {
  margin-bottom: 14px;
}

.tabs button {
  flex: 1;
}

.continue-button {
  margin-left: auto;
}

.tab-page {
  display: none;
}

.tab-page.active {
  display: block;
}

.catalog-browser {
  display: grid;
  gap: 10px;
  margin-bottom: 14px;
}

.catalog-heading {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.catalog-heading h2 {
  margin: 0;
}

.catalog-heading span {
  color: var(--muted);
  font-size: 13px;
}

.catalog-filters {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(112px, 1fr));
  gap: 6px;
}

.catalog-filters button {
  min-height: 34px;
  padding: 0 8px;
  font-size: 13px;
}

.catalog-list {
  display: grid;
  gap: 6px;
  max-height: 260px;
  overflow: auto;
  padding-right: 4px;
}

.catalog-item {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 10px;
  align-items: center;
  min-height: 54px;
  padding: 8px 10px;
  text-align: left;
}

.catalog-item span {
  display: grid;
  gap: 3px;
  min-width: 0;
}

.catalog-item strong,
.catalog-item small {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.catalog-item small,
.catalog-item em {
  color: var(--muted);
  font-size: 12px;
  font-style: normal;
}

.catalog-item.active em {
  color: var(--text);
}

.field {
  display: grid;
  gap: 7px;
  margin-bottom: 12px;
}

.field span {
  font-size: 13px;
}

.group-training {
  display: grid;
  gap: 8px;
  padding: 12px;
  margin-bottom: 12px;
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 8px;
  background: rgba(32, 38, 42, 0.5);
}

.group-training .field {
  margin: 0;
}

.group-training small {
  color: var(--muted);
  line-height: 1.35;
}

input,
select,
textarea {
  width: 100%;
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 6px;
  color: var(--text);
  background: #20262a;
  min-height: 40px;
  padding: 8px 10px;
}

textarea {
  resize: vertical;
  line-height: 1.45;
}

.settings-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

.settings-grid .field:first-child {
  grid-column: 1 / -1;
}

.status-box,
.commentary,
.opening-card {
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 8px;
  background: rgba(32, 38, 42, 0.76);
  padding: 12px;
  margin: 12px 0;
}

#progressText {
  color: var(--text);
  font-weight: 700;
  margin-bottom: 4px;
}

.move-list {
  display: grid;
  gap: 5px;
  padding-left: 24px;
}

.move-list li {
  padding: 5px 8px;
  border-radius: 5px;
}

.move-list li.current {
  color: var(--text);
  background: rgba(141, 179, 93, 0.2);
}

.opening-cards {
  display: grid;
  gap: 10px;
}

.library-filters {
  margin-bottom: 12px;
}

.opening-card {
  margin: 0;
}

.opening-card header {
  display: flex;
  justify-content: space-between;
  gap: 8px;
  align-items: center;
  margin-bottom: 8px;
}

.badge {
  border-radius: 999px;
  padding: 3px 8px;
  font-size: 12px;
  color: #141914;
  background: var(--accent-2);
}

.editor-form {
  display: grid;
}

.pgn-import {
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  margin-top: 18px;
  padding-top: 16px;
}

@media (max-width: 980px) {
  .app-shell {
    grid-template-columns: 1fr;
  }

  .study-panel,
  .side-panel {
    min-height: auto;
  }

  .board-wrap {
    width: min(92vw, 720px);
  }

  .board-layout {
    grid-template-columns: 1fr;
    justify-items: center;
  }

  .board-commentary {
    position: static;
    width: min(92vw, 720px);
  }
}

@media (max-width: 560px) {
  .app-shell {
    padding: 8px;
  }

  .topbar {
    align-items: flex-start;
    flex-direction: column;
  }

  .settings-grid {
    grid-template-columns: 1fr;
  }

  .catalog-filters {
    grid-template-columns: 1fr 1fr;
  }
}