:root {
  --board-bg: #3d2b1f;
  --line-color: #2a1c12;
  --cell-light: #f0e4c9;
  --cell-dark: #b08d57;
  --accent: #7c3aed;
  --accent2: #b8860b;
  --grad: linear-gradient(120deg, var(--accent), var(--accent2));
  --btn-c1: var(--accent);
  --btn-c2: var(--accent2);
  --btn-grad: linear-gradient(120deg, var(--btn-c1), var(--btn-c2));
  --bg: #f7f3ea;
  --text: #2b2620;
  --card-bg: #ffffff;
  --card-border: #e6ddc9;
  --muted: #7a6f5c;
  --danger: #c0392b;
  --hero-grid: rgba(60, 40, 10, 0.05);
  --p1-color: #2563eb;
  --p2-color: #db2777;
  --p3-color: #16a34a;
  --p4-color: #d97706;
}

:root[data-theme="dark"] {
  --board-bg: #241a12;
  --line-color: #140d08;
  --cell-light: #4a4038;
  --cell-dark: #2c241d;
  --accent: #a78bfa;
  --accent2: #e0b24d;
  /* ボタンの塗りは文字用のaccentよりトーンを落として、暗い背景で発光しすぎないようにする */
  --btn-c1: #7c3aed;
  --btn-c2: #b8860b;
  --bg: #14110d;
  --text: #f0ece2;
  --card-bg: #201b15;
  --card-border: #362d22;
  --muted: #b3a690;
  --danger: #ff8d7d;
  --hero-grid: rgba(255, 255, 255, 0.05);
  --p1-color: #60a5fa;
  --p2-color: #f472b6;
  --p3-color: #4ade80;
  --p4-color: #fbbf24;
}
:root[data-theme="dark"] .ad-slot {
  background: repeating-linear-gradient(45deg, #1c1c20, #1c1c20 10px, #232328 10px, #232328 20px);
  color: #9a9aa2;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Hiragino Sans", "Yu Gothic", "Meiryo", sans-serif;
  background-color: var(--bg);
  background-image:
    radial-gradient(circle, var(--hero-grid) 1px, transparent 1px),
    radial-gradient(900px circle at 15% -10%, color-mix(in srgb, var(--accent) 12%, transparent), transparent 55%),
    radial-gradient(800px circle at 100% 10%, color-mix(in srgb, var(--accent2) 9%, transparent), transparent 55%);
  background-size: 22px 22px, auto, auto;
  background-attachment: fixed;
  color: var(--text);
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  align-items: center;
}

.site-header {
  text-align: center;
  padding: 1.2rem 1rem 0.4rem;
}

.site-header h1 {
  margin: 0;
  font-size: 1.8rem;
  font-weight: 800;
  letter-spacing: -0.01em;
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.subtitle {
  margin: 0.3rem 0 0;
  color: var(--muted);
  font-size: 0.95rem;
}

.ad-slot {
  width: 100%;
  max-width: 720px;
  min-height: 60px;
  margin: 0.8rem auto;
  display: flex;
  align-items: center;
  justify-content: center;
  background: repeating-linear-gradient(45deg, #eee, #eee 10px, #e2e2e2 10px, #e2e2e2 20px);
  color: #999;
  font-size: 0.8rem;
  border-radius: 6px;
}

main {
  width: 100%;
  max-width: 720px;
  padding: 0 1rem 2rem;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.hidden {
  display: none !important;
}

.game-area {
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.setup-screen {
  width: 100%;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 12px;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.06);
  padding: 1.5rem 1.2rem;
  margin-bottom: 1rem;
  text-align: center;
}

.setup-screen h2 {
  margin-top: 0;
  font-size: 1.15rem;
}

.mode-buttons {
  display: flex;
  flex-direction: column;
  gap: 0.7rem;
  max-width: 320px;
  margin: 1rem auto 0;
}

.mode-btn {
  padding: 0.8rem 1rem;
  border: none;
  border-radius: 8px;
  background: var(--btn-grad);
  color: #fff;
  font-size: 1rem;
  font-weight: bold;
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.mode-btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 6px 16px color-mix(in srgb, var(--btn-c1) 35%, transparent);
}

.mode-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

.link-btn {
  border: none;
  background: none;
  color: var(--accent);
  font-size: 0.85rem;
  cursor: pointer;
  text-decoration: underline;
  padding: 0.3rem;
}

.online-choice {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
  margin-top: 1rem;
}

.join-row {
  display: flex;
  gap: 0.5rem;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
}

.join-row input,
.name-input {
  padding: 0.6rem 0.7rem;
  border: 1px solid var(--card-border);
  border-radius: 6px;
  background: var(--card-bg);
  color: var(--text);
  font-size: 1rem;
}

.join-row input {
  width: 130px;
  text-align: center;
  text-transform: uppercase;
  letter-spacing: 0.15em;
}

.name-input {
  width: min(100%, 260px);
  display: block;
  margin: 0.5rem auto 1rem;
  text-align: center;
}

.host-wait {
  margin-top: 1.2rem;
  padding-top: 1rem;
  border-top: 1px solid var(--card-border);
}

.room-code {
  font-size: 2rem;
  font-weight: bold;
  letter-spacing: 0.2em;
  color: var(--accent);
  margin: 0.5rem 0;
}

.online-status {
  color: var(--muted);
  font-size: 0.9rem;
  margin: 0.5rem 0 0;
}

.online-error {
  color: var(--danger);
  font-size: 0.9rem;
  margin-top: 0.8rem;
}

#online-connection-status {
  width: 100%;
  text-align: center;
  margin: 0 0 0.6rem;
}

#quit-online-btn {
  margin-top: 0.8rem;
}

.connection-health {
  position: sticky;
  top: 0.5rem;
  z-index: 20;
  margin: 0 0 0.7rem;
  padding: 0.7rem 1rem;
  width: 100%;
  border: 1px solid color-mix(in srgb, var(--danger) 45%, transparent);
  border-radius: 0.6rem;
  background: color-mix(in srgb, var(--danger) 12%, var(--card-bg));
  color: var(--danger);
  font-weight: 700;
  text-align: center;
}

/* 座席設定・オンラインロビーの席割り当て(このゲーム固有の新規コンポーネント。billiardsのクラス名を踏襲) */
.seat-editor {
  display: grid;
  gap: 0.55rem;
  margin: 1rem 0;
  text-align: left;
}
.seat-row {
  display: grid;
  grid-template-columns: 90px minmax(100px, 1.4fr) minmax(92px, 1fr);
  align-items: center;
  gap: 0.5rem;
  padding: 0.6rem 0.7rem;
  border: 1px solid var(--card-border);
  border-radius: 9px;
  background: color-mix(in srgb, var(--accent) 5%, var(--card-bg));
}
.seat-label {
  font-weight: 800;
  color: var(--accent);
  font-size: 0.9rem;
}
.seat-row select,
.seat-row input {
  padding: 0.5rem 0.6rem;
  border: 1px solid var(--card-border);
  border-radius: 7px;
  background: var(--card-bg);
  color: var(--text);
  font: inherit;
}
.seat-team {
  font-size: 0.82rem;
  color: var(--muted);
  text-align: right;
}
.seat-row.p1 .seat-label { color: var(--p1-color); }
.seat-row.p2 .seat-label { color: var(--p2-color); }
.seat-row.p3 .seat-label { color: var(--p3-color); }
.seat-row.p4 .seat-label { color: var(--p4-color); }

.roster {
  list-style: none;
  padding: 0;
  margin: 0.6rem auto;
  max-width: 420px;
  text-align: left;
}
.roster li {
  margin: 0.35rem 0;
  padding: 0.5rem 0.7rem;
  border-left: 5px solid var(--muted);
  border-radius: 7px;
  background: color-mix(in srgb, var(--accent) 8%, var(--card-bg));
  font-weight: 700;
}
.roster li.p1 { border-color: var(--p1-color); }
.roster li.p2 { border-color: var(--p2-color); }
.roster li.p3 { border-color: var(--p3-color); }
.roster li.p4 { border-color: var(--p4-color); }

/* 配置フェーズ(このゲーム固有の新規コンポーネント) */
.placement-layout {
  display: flex;
  flex-wrap: wrap;
  gap: 1.2rem;
  justify-content: center;
  align-items: flex-start;
  margin-top: 1rem;
}
.arm-grid {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  grid-template-rows: repeat(5, 1fr);
  gap: 2px;
  width: 260px;
  aspect-ratio: 7 / 5;
  background: var(--board-bg);
  border: 3px solid var(--line-color);
  border-radius: 6px;
  padding: 2px;
  flex-shrink: 0;
}
.arm-cell {
  position: relative;
  border: 1px solid var(--card-border);
  border-radius: 2px;
  background: var(--cell-light);
  color: var(--text);
  font-weight: 800;
  font-size: 0.85rem;
  cursor: pointer;
  padding: 0;
  overflow: hidden;
}
.arm-cell .piece-icon { inset: 5%; }
.arm-cell.filled { background: color-mix(in srgb, var(--accent) 22%, var(--cell-light)); }
.arm-cell:disabled { cursor: default; opacity: 0.7; }
/* 最後に配置した駒が動けるマスのプレビュー(配置フェーズ固有) */
.arm-cell.reachable::after {
  content: "";
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 26%;
  height: 26%;
  border-radius: 50%;
  background: color-mix(in srgb, var(--accent) 55%, transparent);
  pointer-events: none;
}

.placement-controls {
  flex: 1 1 220px;
  min-width: 220px;
  text-align: left;
}
.piece-palette {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin: 0.6rem 0;
}
.palette-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.45rem 0.65rem;
  border: 1px solid var(--card-border);
  border-radius: 8px;
  background: var(--card-bg);
  color: var(--text);
  font-size: 0.85rem;
  cursor: pointer;
}
.palette-btn .piece-icon {
  position: relative;
  inset: auto;
  width: 2rem;
  height: 2rem;
  flex: 0 0 2rem;
}
.palette-btn.armed { border-color: var(--accent); background: color-mix(in srgb, var(--accent) 15%, var(--card-bg)); font-weight: 700; }
.palette-btn:disabled { opacity: 0.4; cursor: not-allowed; }
.formation-buttons { align-items: flex-start; margin: 0.6rem 0 0; }

.status-bar {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.6rem;
  gap: 0.6rem;
  flex-wrap: wrap;
}

.turn-indicator {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: bold;
}

.team-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  font-size: 0.75rem;
  font-weight: 800;
  color: #fff;
}
.team-badge.team-a { background: var(--accent); }
.team-badge.team-b { background: var(--accent2); }

/* 4人の陣営(誰が味方か)を常時表示する */
.team-roster {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin: 0.6rem 0 0;
}
.team-roster-group {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.3rem;
  padding: 0.3rem 0.5rem;
  border-radius: 8px;
  background: color-mix(in srgb, var(--accent) 6%, var(--card-bg));
  border: 1px solid var(--card-border);
}
.team-roster-group.team-b { background: color-mix(in srgb, var(--accent2) 6%, var(--card-bg)); }
.team-roster-label {
  font-size: 0.72rem;
  font-weight: 800;
  color: var(--muted);
  margin-right: 0.1rem;
}
.team-roster-chip {
  font-size: 0.78rem;
  font-weight: 700;
  padding: 0.15rem 0.55rem;
  border-radius: 999px;
  border: 1px solid currentColor;
  white-space: nowrap;
}
.team-roster-chip.p1 { color: var(--p1-color); }
.team-roster-chip.p2 { color: var(--p2-color); }
.team-roster-chip.p3 { color: var(--p3-color); }
.team-roster-chip.p4 { color: var(--p4-color); }
.team-roster-chip.eliminated { opacity: 0.4; text-decoration: line-through; }

/* 王手(ストップザミュージック)演出。.hidden(display:none!important)は使わず、独自の.visible
   トグルでmax-height/opacityを変化させることでポップイン/アウトを表現する */
.check-banner {
  margin: 0 0 0;
  padding: 0 0.9rem;
  border-radius: 8px;
  background: color-mix(in srgb, var(--danger) 15%, var(--card-bg));
  border-width: 0;
  border-style: solid;
  border-color: var(--danger);
  color: var(--danger);
  font-weight: 800;
  text-align: center;
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  transition: max-height 0.25s ease, opacity 0.2s ease, margin 0.25s ease, padding 0.25s ease;
}
.check-banner.visible {
  margin: 0.6rem 0 0;
  padding: 0.5rem 0.9rem;
  border-width: 1px;
  max-height: 80px;
  opacity: 1;
}
.check-banner .check-sub {
  display: block;
  font-weight: 600;
  font-size: 0.8rem;
  opacity: 0.85;
}

.reset-btn {
  padding: 0.5rem 1rem;
  border: none;
  border-radius: 6px;
  background: var(--btn-grad);
  color: #fff;
  font-size: 0.9rem;
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.reset-btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 6px 16px color-mix(in srgb, var(--btn-c1) 35%, transparent);
}

.stats-bar {
  width: 100%;
  display: flex;
  gap: 1.2rem;
  justify-content: center;
  margin-bottom: 0.8rem;
  font-size: 0.9rem;
  color: var(--muted);
}

.board-wrapper {
  width: 100%;
  display: flex;
  justify-content: center;
}

/* 盤面「グランドクロス」(gomoku-othelloの単色盤とは違い、このゲーム固有の市松模様17x17マス・
   十字形に必要な無効マスの表現が新規コンポーネント) */
.board {
  position: relative;
  display: grid;
  grid-template-columns: repeat(17, 1fr);
  grid-template-rows: repeat(17, 1fr);
  background: var(--board-bg);
  border: 3px solid var(--line-color);
  border-radius: 6px;
  width: 100%;
  max-width: 680px;
  aspect-ratio: 1 / 1;
  touch-action: manipulation;
  overflow: hidden;
}

.board.thinking {
  opacity: 0.7;
  pointer-events: none;
}

/* 直前の手の駒が移動元から移動先へ滑るように動く演出(盤の回転後の実際の画面位置を基準にするため
   getBoundingClientRectの差分をtransformで表現する。手番のたびに1回だけ再生する) */
.move-ghost {
  position: absolute;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: clamp(0.5rem, 1.9vw, 0.85rem);
  pointer-events: none;
  z-index: 5;
  transition: transform 0.35s ease;
}
.move-ghost.wide { font-size: clamp(0.35rem, 1.3vw, 0.6rem); }
.move-ghost.p1 { color: var(--p1-color); }
.move-ghost.p2 { color: var(--p2-color); }
.move-ghost.p3 { color: var(--p3-color); }
.move-ghost.p4 { color: var(--p4-color); }
.move-ghost.piece-rot-90 > .piece-icon,
.move-ghost.piece-rot-90 > .piece-glyph { transform: rotate(90deg); }
.move-ghost.piece-rot-180 > .piece-icon,
.move-ghost.piece-rot-180 > .piece-glyph { transform: rotate(180deg); }
.move-ghost.piece-rot-270 > .piece-icon,
.move-ghost.piece-rot-270 > .piece-glyph { transform: rotate(270deg); }

.piece-icon {
  position: absolute;
  inset: 10%;
  z-index: 1;
  display: block;
  background-image: var(--piece-icon);
  background-size: contain;
  background-repeat: no-repeat;
  background-position: center;
  isolation: isolate;
  pointer-events: none;
}
.piece-icon.p1 { color: var(--p1-color); }
.piece-icon.p2 { color: var(--p2-color); }
.piece-icon.p3 { color: var(--p3-color); }
.piece-icon.p4 { color: var(--p4-color); }
@supports (((-webkit-mask-image: linear-gradient(#000, #000)) or (mask-image: linear-gradient(#000, #000))) and (mix-blend-mode: multiply)) {
  .piece-icon::after {
    content: "";
    position: absolute;
    inset: 0;
    background-color: currentColor;
    -webkit-mask-image: var(--piece-icon);
    mask-image: var(--piece-icon);
    -webkit-mask-size: contain;
    mask-size: contain;
    -webkit-mask-repeat: no-repeat;
    mask-repeat: no-repeat;
    -webkit-mask-position: center;
    mask-position: center;
    mix-blend-mode: multiply;
    opacity: 0.7; /* チーム色の重ねが濃くなりすぎないよう少し薄める */
    pointer-events: none;
  }
}
/* ルール説明の駒アイコンはチーム所属を持たないので、色重ねはせず素の画像をそのまま見せる
   (周囲のテキスト色を拾って真っ黒に見えてしまう不具合の修正も兼ねる) */
.piece-move-diagrams .piece-icon::after {
  content: none;
}
.piece-glyph { display: inline-block; }

.cell {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  border: none;
  padding: 0;
  font-size: clamp(0.5rem, 1.9vw, 0.85rem);
  font-weight: 800;
  cursor: pointer;
}
.cell.wide { font-size: clamp(0.35rem, 1.3vw, 0.6rem); }
/* 将棋盤のように市松模様(チェス盤風)ではなく単色の木目調にし、マス目は罫線で区切る */
.cell.light, .cell.dark { background: var(--cell-dark); }
.cell.invalid { background: transparent; cursor: default; }
.cell:not(.invalid) { border: 1px solid color-mix(in srgb, var(--line-color) 45%, transparent); }
.cell:disabled { cursor: default; }

.cell.p1 { color: var(--p1-color); }
.cell.p2 { color: var(--p2-color); }
.cell.p3 { color: var(--p3-color); }
.cell.p4 { color: var(--p4-color); }

/* 将棋のように、駒の持ち主の向き(盤中央側)に文字が向くよう回転させる */
.cell.piece-rot-90 { transform: rotate(90deg); }
.cell.piece-rot-180 { transform: rotate(180deg); }
.cell.piece-rot-270 { transform: rotate(270deg); }

/* 直前の手(移動元・移動先)を示す。CPU/相手の手も含め、どの駒がどこへ動いたか一目で分かるように */
.cell.last-move {
  box-shadow: inset 0 0 0 999px color-mix(in srgb, var(--accent2) 30%, transparent);
}

.cell.selected::after {
  content: "";
  position: absolute;
  inset: 3px;
  z-index: 2;
  border: 3px solid var(--accent);
  border-radius: 4px;
  pointer-events: none;
}
.cell.legal-move::before {
  content: "";
  position: absolute;
  z-index: 2;
  width: 26%;
  height: 26%;
  border-radius: 50%;
  background: color-mix(in srgb, var(--accent) 55%, transparent);
  pointer-events: none;
}
.cell.legal-move.has-piece::before {
  width: 100%;
  height: 100%;
  border-radius: 0;
  background: color-mix(in srgb, var(--danger) 30%, transparent);
}

.overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.55);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
}

.overlay.hidden {
  display: none;
}

.overlay-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 12px;
  padding: 1.5rem 2rem;
  text-align: center;
  max-width: 90%;
  width: 380px;
  position: relative;
  z-index: 1001;
}

.result-title {
  font-size: 1.4rem;
  font-weight: bold;
  margin: 0 0 0.5rem;
}
.result-meta {
  margin: 0.2rem 0 1rem;
  color: var(--muted);
  font-size: 0.92rem;
}
.result-scoreboard {
  list-style: none;
  padding: 0;
  margin: 0 auto 1rem;
  max-width: 300px;
  text-align: left;
}
.result-scoreboard li {
  margin: 0.3rem 0;
  padding: 0.45rem 0.7rem;
  border-radius: 7px;
  background: color-mix(in srgb, var(--accent) 8%, var(--card-bg));
  font-weight: 700;
}

.result-actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.7rem;
  margin-top: 0.5rem;
}
.secondary-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.7rem 1rem;
  border: 1px solid var(--accent);
  border-radius: 8px;
  background: transparent;
  color: var(--accent);
  font-weight: 700;
  text-decoration: none;
  cursor: pointer;
  font: inherit;
}
.secondary-btn:hover {
  transform: translateY(-1px);
}

.howto {
  width: 100%;
  margin-top: 2rem;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  padding: 1rem 1.2rem;
  border-radius: 8px;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.06);
}

.howto h2 {
  margin-top: 0;
  font-size: 1.2rem;
}

.howto ul {
  padding-left: 1.2rem;
  line-height: 1.6;
}
.howto .disclaimer {
  color: var(--muted);
  font-size: 0.88rem;
  line-height: 1.6;
}
.howto h3 {
  margin: 1.2rem 0 0.3rem;
  font-size: 1rem;
}

/* ルール説明の駒の動き図。logic.jsのPIECE_SPECSから生成される(script.jsのbuildMoveDiagram)。 */
.piece-move-diagrams {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(110px, 1fr));
  gap: 0.8rem;
  margin-top: 0.8rem;
}
.move-diagram-card {
  background: var(--bg);
  border: 1px solid var(--card-border);
  border-radius: 10px;
  padding: 0.6rem;
  text-align: center;
}
.move-diagram-label {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.35rem;
  margin: 0 0 0.5rem;
  font-size: 0.8rem;
  font-weight: 700;
}
.move-diagram-label .piece-icon {
  position: relative;
  inset: auto;
  width: 1.65rem;
  height: 1.65rem;
  flex: 0 0 1.65rem;
}
.move-diagram-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  grid-template-rows: repeat(5, 1fr);
  gap: 2px;
  aspect-ratio: 1 / 1;
  max-width: 120px;
  margin: 0 auto;
  background: var(--board-bg);
  border-radius: 4px;
  padding: 2px;
}
.move-diagram-cell {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--cell-light);
  border-radius: 2px;
  font-size: 0.75rem;
  font-weight: 800;
  color: var(--accent2);
}
.move-diagram-cell.piece {
  background: var(--cell-dark);
  color: var(--accent);
  font-size: 0.6rem;
}
.move-diagram-cell.piece .piece-icon { inset: 7%; }
.move-diagram-cell.piece.wide { font-size: 0.4rem; }
.move-diagram-cell.target::before {
  content: "";
  width: 32%;
  height: 32%;
  border-radius: 50%;
  background: color-mix(in srgb, var(--accent) 55%, transparent);
}
.move-diagram-note {
  margin: 0.5rem 0 0;
  font-size: 0.72rem;
  color: var(--muted);
  line-height: 1.4;
  text-align: left;
}

.error {
  color: var(--danger);
  min-height: 1.2em;
}

.site-footer {
  margin-top: auto;
  padding: 1rem;
  color: var(--muted);
  font-size: 0.8rem;
}

@media (max-width: 480px) {
  .site-header h1 {
    font-size: 1.4rem;
  }
  .overlay-card {
    padding: 1.2rem 1rem;
  }
  .seat-row {
    grid-template-columns: 1fr;
    text-align: left;
  }
  .seat-team {
    text-align: left;
  }
  .placement-layout {
    flex-direction: column;
    align-items: center;
  }
  .arm-grid {
    width: 100%;
    max-width: 260px;
  }
}

.site-nav {
  width: 100%;
  padding: 0.6rem 1rem;
  font-size: 0.85rem;
  box-sizing: border-box;
}
.site-nav a {
  display: inline-flex;
  align-items: center;
  color: var(--text);
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 999px;
  padding: 0.35rem 0.9rem;
  text-decoration: none;
  transition: border-color 0.15s ease, transform 0.15s ease;
}
.site-nav a:hover {
  border-color: var(--accent);
  transform: translateY(-1px);
}