/* 四子棋 — 由地端模型 Qwen3.8-27B-ROCmFP4-FAST 撰寫
   手機優先：直向 375px 內完整顯示棋盤與面板，不產生橫向捲軸。 */

:root {
  --bg: #0f172a;
  --panel: #1e293b;
  --panel-border: #334155;
  --text: #e2e8f0;
  --muted: #94a3b8;
  --accent: #38bdf8;
  --accent-contrast: #06263a;
  --red: #e5484d;
  --yellow: #ffd23f;
  --win: #4ade80;
  --lose: #f87171;
  --draw: #c4b5fd;
  --focus: #7dd3fc;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  width: 100%;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: "PingFang TC", "Microsoft JhengHei", "Noto Sans TC",
               system-ui, -apple-system, sans-serif;
  line-height: 1.5;
  /* 手機直向不允許橫向捲動 */
  overflow-x: hidden;
}

#board-wrap,
canvas,
img,
select,
button { max-width: 100%; }

#board-wrap {
  width: min(92vw, 460px);
  margin: 0 auto;
}

canvas#board {
  display: block;
  width: 100%;
  aspect-ratio: 7 / 6;
  touch-action: manipulation;
  border-radius: 12px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.45);
  cursor: pointer;
}

/* ---------- 版面 ---------- */
.app-header {
  text-align: center;
  padding: 14px 12px 4px;
}

.app-header h1 {
  margin: 0;
  font-size: clamp(1.35rem, 4vw, 1.9rem);
  letter-spacing: 0.06em;
}

.app-header .subtitle {
  font-size: 0.62em;
  color: var(--muted);
  font-weight: 400;
}

.credit {
  margin: 4px 0 0;
  font-size: 0.8rem;
  color: var(--accent);
}

/* ---------- 狀態列 ---------- */
#status {
  text-align: center;
  margin: 10px auto 8px;
  min-height: 1.6em;
  font-size: clamp(1.05rem, 3.4vw, 1.3rem);
  font-weight: 700;
  padding: 6px 14px;
  width: fit-content;
  max-width: 92vw;
  border-radius: 999px;
  background: var(--panel);
  border: 1px solid var(--panel-border);
}

#status[data-state="play"]      { color: var(--accent); }
#status[data-state="thinking"]  { color: var(--yellow); }
#status[data-state="win"]       { color: var(--win); }
#status[data-state="lose"]      { color: var(--lose); }
#status[data-state="draw"]      { color: var(--draw); }

#last-move {
  text-align: center;
  color: var(--muted);
  font-size: 0.85rem;
  margin: 6px 0 12px;
}

/* ---------- 比分板 ---------- */
#scoreboard {
  display: flex;
  justify-content: center;
  gap: 8px;
  flex-wrap: wrap;
  padding: 0 12px 4px;
}

.score {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  min-width: 88px;
  padding: 8px 10px;
  background: var(--panel);
  border: 1px solid var(--panel-border);
  border-radius: 10px;
}

.score-name {
  font-size: 0.78rem;
  color: var(--muted);
  white-space: nowrap;
}

.score-value {
  font-size: 1.35rem;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
}

/* ---------- 操作面板 ---------- */
#controls {
  margin: 12px auto 8px;
  width: min(92vw, 460px);
  padding: 12px;
  background: var(--panel);
  border: 1px solid var(--panel-border);
  border-radius: 12px;
  display: grid;
  gap: 10px;
}

.field {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  flex-wrap: wrap;
}

.field label {
  font-size: 0.9rem;
  color: var(--text);
  font-weight: 600;
}

select {
  appearance: none;
  background: var(--bg);
  color: var(--text);
  border: 2px solid var(--panel-border);
  border-radius: 8px;
  padding: 8px 12px;
  font-size: 0.95rem;
  min-width: 150px;
  flex: 1;
}

.btn-row {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  justify-content: center;
}

button {
  background: var(--accent);
  color: var(--accent-contrast);
  border: 2px solid transparent;
  border-radius: 8px;
  padding: 10px 16px;
  font-size: 0.95rem;
  font-weight: 700;
  cursor: pointer;
  flex: 1 1 auto;
  min-width: 104px;
  text-align: center;
}

button:disabled {
  background: var(--panel-border);
  color: var(--muted);
  cursor: not-allowed;
}

button.secondary {
  background: transparent;
  color: var(--text);
  border-color: var(--panel-border);
}

/* 清楚的 focus 狀態（鍵盤可及） */
button:focus-visible,
select:focus-visible,
canvas:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 2px;
}

/* 觸控目標至少 44px */
button, select { min-height: 44px; }

.app-footer {
  text-align: center;
  color: var(--muted);
  font-size: 0.78rem;
  padding: 10px 12px 18px;
}

/* ---------- 寬螢幕：棋盤與面板並排，仍不橫向溢出 ---------- */
@media (min-width: 860px) {
  body {
    display: flex;
    justify-content: center;
    align-items: flex-start;
    min-height: 100vh;
  }

  #c4-root {
    display: grid;
    grid-template-columns: minmax(360px, 560px) 340px;
    gap: 20px;
    align-items: start;
    max-width: 1000px;
  }

  .app-header { grid-column: 1 / -1; }

  #board-wrap { width: 100%; }

  #controls {
    width: 100%;
    position: sticky;
    top: 16px;
  }
}