/* Layout and board styles. Colors come from CSS variables defined
   by the active theme stylesheet (styles/themes/*.css). */

* {
  box-sizing: border-box;
}

/* Author display rules (e.g. flex) must not defeat the hidden attribute. */
[hidden] {
  display: none !important;
}

body {
  margin: 0;
  font-family: "Segoe UI", system-ui, -apple-system, sans-serif;
  background: var(--bg-color);
  color: var(--text-color);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.75rem;
  padding: 0.75rem 1.5rem;
  background: var(--panel-bg);
  border-bottom: 1px solid var(--border-color);
}

.app-title {
  margin: 0;
  font-size: 1.5rem;
}

.app-controls {
  display: flex;
  align-items: flex-end;
  flex-wrap: wrap;
  gap: 1rem;
}

.control-field {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  font-size: 0.9rem;
}

.control-field[hidden] {
  display: none;
}

.control-label {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--muted-text);
}

.control-field select,
.control-field input[type="range"] {
  min-width: 8rem;
  padding: 0.35rem 0.5rem;
  font-size: 0.95rem;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  background: var(--bg-color);
  color: var(--text-color);
}

.control-field input[type="range"] {
  padding: 0;
  accent-color: var(--accent-color);
}

.btn {
  padding: 0.5rem 1rem;
  font-size: 1rem;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  background: var(--accent-color);
  color: var(--accent-text);
  cursor: pointer;
}

.btn:hover {
  filter: brightness(1.1);
}

.btn-icon {
  background: var(--panel-bg);
  color: var(--text-color);
  padding: 0.5rem 0.65rem;
  line-height: 1;
}

.app-main {
  flex: 1;
  display: flex;
  flex-wrap: wrap;
  gap: 1.5rem;
  justify-content: center;
  align-items: flex-start;
  padding: 1.5rem;
}

/* Board */

.board-panel {
  flex: 0 1 auto;
  position: relative;
}

/* Transient center-board announcements (check, game start/end). */

.board-toast {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  pointer-events: none;
  z-index: 20;
}

.board-toast span {
  padding: 0.55em 1.1em;
  border-radius: 12px;
  font-size: clamp(1.3rem, 4.5vw, 2rem);
  font-weight: 700;
  text-align: center;
  max-width: 85%;
  background: var(--panel-bg);
  color: var(--text-color);
  border: 3px solid var(--accent-color);
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.35);
  animation: toast-pop 2000ms ease forwards;
}

.board-toast.check span {
  border-color: #dc2626;
  color: #dc2626;
}

.board-toast.end span {
  border-color: var(--accent-color);
}

.board-toast.start span {
  border-color: #16a34a;
}

@keyframes toast-pop {
  0% {
    opacity: 0;
    transform: scale(0.7);
  }
  8% {
    opacity: 1;
    transform: scale(1.03);
  }
  12% {
    transform: scale(1);
  }
  82% {
    opacity: 1;
  }
  100% {
    opacity: 0;
    transform: scale(0.96);
  }
}

.board {
  position: relative;
  display: grid;
  grid-template-columns: repeat(8, 1fr);
  grid-template-rows: repeat(8, 1fr);
  width: min(88vw, 640px);
  aspect-ratio: 1 / 1;
  border: 4px solid var(--board-border);
  border-radius: 4px;
  user-select: none;
}

.board.locked .square {
  cursor: wait;
}

.square {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: clamp(1.5rem, 8vw, 3.5rem);
  line-height: 1;
  cursor: pointer;
}

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

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

.square.selected {
  outline: 3px solid var(--highlight-selected);
  outline-offset: -3px;
}

.square.legal-move::after {
  content: "";
  position: absolute;
  width: 28%;
  height: 28%;
  border-radius: 50%;
  background: var(--highlight-move);
}

.square.legal-capture::after {
  content: "";
  position: absolute;
  inset: 6%;
  border: 4px solid var(--highlight-move);
  border-radius: 50%;
}

.square.last-move {
  box-shadow: inset 0 0 0 100vmax var(--highlight-last-move);
}

/* King under attack: red glow beneath the piece. */
.square.check::before {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(circle, rgba(220, 38, 38, 0.6) 0%, rgba(220, 38, 38, 0.25) 55%, rgba(220, 38, 38, 0) 75%);
}

.piece {
  z-index: 1;
  pointer-events: none;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  height: 100%;
}

.piece-svg svg {
  display: block;
  width: 94%;
  height: 94%;
}

.piece-text.white {
  color: var(--piece-white);
  text-shadow: 0 0 2px var(--piece-black);
}

.piece-text.black {
  color: var(--piece-black);
  text-shadow: 0 0 2px var(--piece-white);
}

/* Promotion picker */

.promotion-dialog {
  position: absolute;
  z-index: 10;
  width: 12.5%;
  display: flex;
  flex-direction: column;
  background: var(--panel-bg);
  border: 2px solid var(--accent-color);
  border-radius: 6px;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.35);
  overflow: hidden;
}

.promotion-choice {
  aspect-ratio: 1 / 1;
  padding: 4%;
  border: none;
  background: var(--panel-bg);
  font-size: clamp(1.5rem, 6vw, 3rem);
  line-height: 1;
  cursor: pointer;
}

.promotion-choice:hover {
  background: var(--status-bg);
}

.promotion-choice .piece {
  pointer-events: none;
}

/* Online play */

.online-panel {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
  margin-bottom: 1rem;
}

.join-row {
  display: flex;
  gap: 0.5rem;
}

.join-row input {
  flex: 1;
  min-width: 0;
  padding: 0.5rem 0.75rem;
  font-size: 1.1rem;
  letter-spacing: 0.2em;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  background: var(--bg-color);
  color: var(--text-color);
}

.online-hint {
  margin: 0;
  font-size: 0.85rem;
  color: var(--muted-text);
}

.pin-banner {
  margin-bottom: 0.75rem;
  padding: 0.6rem 0.75rem;
  border: 2px dashed var(--accent-color);
  border-radius: 8px;
  text-align: center;
  font-size: 1.1rem;
}

.pin-banner strong {
  font-size: 1.5rem;
  letter-spacing: 0.25em;
  margin-left: 0.4rem;
}

.copy-pin {
  vertical-align: middle;
  margin-left: 0.5rem;
  padding: 0.35rem 0.45rem;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  background: var(--panel-bg);
  color: var(--text-color);
  cursor: pointer;
  line-height: 0;
}

.copy-pin:hover {
  border-color: var(--accent-color);
  color: var(--accent-color);
}

.copy-pin .icon-check {
  display: none;
}

.copy-pin.copied {
  border-color: var(--accent-color);
  color: var(--accent-color);
}

.copy-pin.copied .icon-copy {
  display: none;
}

.copy-pin.copied .icon-check {
  display: inline;
}

/* Draw / rematch offers */

.btn-small {
  padding: 0.35rem 0.7rem;
  font-size: 0.85rem;
}

.btn-secondary {
  background: var(--panel-bg);
  color: var(--text-color);
}

.online-actions {
  display: flex;
  gap: 0.5rem;
  margin-top: 0.6rem;
}

.offer-banner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
  flex-wrap: wrap;
  margin-top: 0.6rem;
  padding: 0.5rem 0.75rem;
  border: 2px dashed var(--accent-color);
  border-radius: 8px;
  font-size: 0.9rem;
}

.offer-actions {
  display: flex;
  gap: 0.4rem;
}

/* Chat */

.chat-panel {
  margin-top: 0.75rem;
}

.chat-messages {
  max-height: 180px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  padding: 0.5rem;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  background: var(--bg-color);
  font-size: 0.9rem;
  overflow-wrap: anywhere;
}

.chat-messages:empty::before {
  content: "Say hi to your opponent…";
  color: var(--muted-text);
}

.chat-msg.you {
  color: var(--text-color);
}

.chat-msg.them {
  color: var(--accent-color);
}

.chat-msg.system {
  color: var(--muted-text);
  font-style: italic;
}

.chat-form {
  display: flex;
  gap: 0.4rem;
  margin-top: 0.5rem;
}

.chat-form input {
  flex: 1;
  min-width: 0;
  padding: 0.4rem 0.6rem;
  /* At least 16px, or iOS Safari zooms the page when the field is focused. */
  font-size: 1rem;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  background: var(--bg-color);
  color: var(--text-color);
}

.control-field select:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

/* Sidebar */

.sidebar {
  flex: 0 1 260px;
  min-width: 220px;
  background: var(--panel-bg);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 1rem;
}

.sidebar-heading {
  margin: 1rem 0 0.5rem;
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.game-status {
  font-weight: 600;
  padding: 0.5rem 0.75rem;
  border-radius: 6px;
  background: var(--status-bg);
}

/* Captured pieces tray */

.captured-panel {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}

.captured-row {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  min-height: 1.9rem;
}

.captured-label {
  flex: 0 0 3.2rem;
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--muted-text);
}

.captured-pieces {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.1rem;
  flex: 1;
}

.captured-pieces:empty::before {
  content: "—";
  color: var(--muted-text);
}

.piece.captured-piece {
  width: 1.6rem;
  height: 1.6rem;
  font-size: 1.3rem;
  pointer-events: auto;
}

.material-lead {
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  color: var(--accent-color);
}

/* Collapsible move list */

.moves-details {
  margin-top: 0.75rem;
}

.moves-details summary {
  cursor: pointer;
  list-style: revert;
}

.move-history {
  margin: 0.4rem 0 0;
  padding-left: 2rem;
  max-height: 220px;
  overflow-y: auto;
  font-variant-numeric: tabular-nums;
}

.move-history li {
  padding: 0.15rem 0;
}

.app-footer {
  text-align: center;
  padding: 0.75rem;
  font-size: 0.85rem;
  color: var(--muted-text);
}

.footer-link {
  color: var(--text-color);
  text-decoration: none;
  border-bottom: 1px solid var(--border-color);
  white-space: nowrap;
}

.footer-link:hover {
  border-bottom-color: var(--accent-color);
}

.github-mark {
  vertical-align: -2px;
  margin-right: 2px;
}

@media (max-width: 720px) {
  .app-main {
    padding: 0.75rem;
  }

  .sidebar {
    flex: 1 1 100%;
  }
}