/* =========================================================
   主题变量：默认深色，[data-theme="light"] 覆盖为浅色
   ========================================================= */
:root {
  color-scheme: dark;

  --bg: #06090f;
  --text: #e8eef7;
  --muted: #7f8ea6;
  --line: rgba(148, 163, 184, 0.14);
  --accent: #5eead4;

  --topbar-bg: linear-gradient(180deg, #0d1320, #0a0f19);
  --group-bg: rgba(148, 163, 184, 0.07);
  --group-border: rgba(148, 163, 184, 0.1);
  --btn-text: #c4d0e2;
  --btn-hover-bg: rgba(148, 163, 184, 0.16);
  --btn-hover-text: #ffffff;
  --toggle-bg: rgba(94, 234, 212, 0.16);
  --toggle-text: #8ff0df;
  --puzzle-btn-bg: rgba(251, 191, 36, 0.14);
  --puzzle-btn-text: #fcd34d;
  --puzzle-btn-hover-bg: rgba(251, 191, 36, 0.24);
  --puzzle-btn-hover-text: #fde68a;
  --danger-text: #fca5a5;

  --stage-bg: #080c14;
  --hud-bg: rgba(10, 15, 25, 0.62);
  --hud-border: rgba(148, 163, 184, 0.12);
  --hud-text: #8b9cb3;
  --hud-active: #cfe3ff;
  --legend: #52627a;

  --panel-bg: rgba(12, 18, 30, 0.97);
  --panel-border: rgba(148, 163, 184, 0.18);
  --panel-shadow: 0 20px 46px rgba(0, 0, 0, 0.55);
  --divider: rgba(148, 163, 184, 0.12);
  --row-bg: rgba(148, 163, 184, 0.06);
  --row-border: rgba(148, 163, 184, 0.08);
  --row-name: #dbe6f5;
  --row-meta: #7f8ea6;
  --empty-text: #6b7a90;
  --input-bg: rgba(148, 163, 184, 0.06);
  --input-border: rgba(148, 163, 184, 0.18);
  --input-text: #dbe6f5;
  --input-focus: rgba(94, 234, 212, 0.5);
  --input-focus-bg: rgba(94, 234, 212, 0.07);
  --placeholder: #5f6f85;
  --tip-text: #5d6b80;

  --tray-bg:
    radial-gradient(120% 170% at 12% 0%, rgba(94, 234, 212, 0.07), transparent 62%),
    linear-gradient(180deg, #0a0f19, #0d1320);
  --tray-sub: #748498;
  --tray-tip: #65758b;
  --tray-tip-em: #9fb3c8;
  --slot-border: rgba(148, 163, 184, 0.3);
  --slot-bg: rgba(148, 163, 184, 0.045);
  --slot-hover-border: rgba(94, 234, 212, 0.5);
  --slot-hover-bg: rgba(94, 234, 212, 0.08);
  --poly-fill: hsl(190 66% 56%);
  --poly-stroke: #060a12;
  --tray-shadow: 0 6px 10px rgba(0, 0, 0, 0.55);
}

:root[data-theme="light"] {
  color-scheme: light;

  --bg: #eef1f7;
  --text: #1f2937;
  --muted: #64748b;
  --line: rgba(15, 23, 42, 0.1);
  --accent: #0d9488;

  --topbar-bg: linear-gradient(180deg, #ffffff, #f2f5fa);
  --group-bg: rgba(15, 23, 42, 0.045);
  --group-border: rgba(15, 23, 42, 0.07);
  --btn-text: #334155;
  --btn-hover-bg: rgba(15, 23, 42, 0.08);
  --btn-hover-text: #0f172a;
  --toggle-bg: rgba(13, 148, 136, 0.14);
  --toggle-text: #0f766e;
  --puzzle-btn-bg: rgba(217, 119, 6, 0.14);
  --puzzle-btn-text: #b45309;
  --puzzle-btn-hover-bg: rgba(217, 119, 6, 0.22);
  --puzzle-btn-hover-text: #92400e;
  --danger-text: #b91c1c;

  --stage-bg: #e9edf4;
  --hud-bg: rgba(255, 255, 255, 0.85);
  --hud-border: rgba(15, 23, 42, 0.1);
  --hud-text: #475569;
  --hud-active: #0f172a;
  --legend: #94a3b8;

  --panel-bg: rgba(255, 255, 255, 0.98);
  --panel-border: rgba(15, 23, 42, 0.1);
  --panel-shadow: 0 18px 40px rgba(15, 23, 42, 0.14);
  --divider: rgba(15, 23, 42, 0.08);
  --row-bg: rgba(15, 23, 42, 0.035);
  --row-border: rgba(15, 23, 42, 0.06);
  --row-name: #1e293b;
  --row-meta: #64748b;
  --empty-text: #94a3b8;
  --input-bg: #ffffff;
  --input-border: rgba(15, 23, 42, 0.14);
  --input-text: #1f2937;
  --input-focus: rgba(13, 148, 136, 0.55);
  --input-focus-bg: #ffffff;
  --placeholder: #94a3b8;
  --tip-text: #94a3b8;

  --tray-bg:
    radial-gradient(120% 170% at 12% 0%, rgba(13, 148, 136, 0.08), transparent 62%),
    linear-gradient(180deg, #f7f9fc, #e9edf5);
  --tray-sub: #64748b;
  --tray-tip: #64748b;
  --tray-tip-em: #334155;
  --slot-border: rgba(15, 23, 42, 0.18);
  --slot-bg: rgba(15, 23, 42, 0.03);
  --slot-hover-border: rgba(13, 148, 136, 0.5);
  --slot-hover-bg: rgba(13, 148, 136, 0.06);
  --poly-fill: hsl(190 62% 54%);
  --poly-stroke: #ffffff;
  --tray-shadow: 0 6px 12px rgba(15, 23, 42, 0.18);
}

* { box-sizing: border-box; }

html, body { height: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: ui-sans-serif, system-ui, -apple-system, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  -webkit-font-smoothing: antialiased;
  overflow: hidden;
  -webkit-tap-highlight-color: transparent;
  transition: background 0.2s, color 0.2s;
}

.app {
  display: grid;
  grid-template-rows: auto minmax(0, 1fr) auto;
  height: 100vh;
  height: 100dvh;
}

/* ---------------- 顶栏 ---------------- */
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding: 11px 16px;
  border-bottom: 1px solid var(--line);
  background: var(--topbar-bg);
  z-index: 3;
}

.brand { display: flex; align-items: center; gap: 10px; min-width: 0; }

.brand-dot {
  width: 26px;
  height: 26px;
  border-radius: 9px;
  flex: none;
  background: conic-gradient(from 200deg, #5eead4, #818cf8, #f472b6, #fbbf24, #5eead4);
  box-shadow: 0 0 18px rgba(94, 234, 212, 0.35);
}

.brand-text { display: flex; flex-direction: column; line-height: 1.2; min-width: 0; }
.brand-text strong { font-size: 14px; letter-spacing: 0.3px; white-space: nowrap; }
.brand-text span { font-size: 10.5px; color: var(--muted); letter-spacing: 0.4px; white-space: nowrap; }

.tools { display: flex; gap: 7px; flex-wrap: wrap; justify-content: flex-end; }

.group {
  display: flex;
  gap: 2px;
  padding: 3px;
  border-radius: 10px;
  background: var(--group-bg);
  border: 1px solid var(--group-border);
}

.tools button {
  appearance: none;
  border: 0;
  background: transparent;
  color: var(--btn-text);
  font: inherit;
  font-size: 12px;
  line-height: 1;
  padding: 7px 8px;
  border-radius: 7px;
  cursor: pointer;
  transition: background 0.14s, color 0.14s;
  white-space: nowrap;
}

.tools button:hover { background: var(--btn-hover-bg); color: var(--btn-hover-text); }
.tools button:active { transform: translateY(1px); }
.tools button.toggle[aria-pressed="true"] { background: var(--toggle-bg); color: var(--toggle-text); }
.tools button:disabled { opacity: 0.3; cursor: default; pointer-events: none; }
.tools button.hidden { display: none; }
.tools button[data-act="puzzle"] { background: var(--puzzle-btn-bg); color: var(--puzzle-btn-text); }
.tools button[data-act="puzzle"]:hover { background: var(--puzzle-btn-hover-bg); color: var(--puzzle-btn-hover-text); }
.tools button[data-act="exit"] { color: var(--danger-text); }
.tools button[data-act="theme"] { font-size: 14px; padding: 5px 7px; }

/* ---------------- 画布 ---------------- */
.stage { position: relative; min-height: 0; background: var(--stage-bg); }

#board {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
  touch-action: none;
  cursor: default;
}

.hud {
  position: absolute;
  top: 14px;
  left: 16px;
  font-size: 12px;
  color: var(--hud-text);
  letter-spacing: 0.3px;
  pointer-events: none;
  background: var(--hud-bg);
  border: 1px solid var(--hud-border);
  padding: 6px 10px;
  border-radius: 8px;
  backdrop-filter: blur(6px);
  font-variant-numeric: tabular-nums;
}

.hud.is-active { color: var(--hud-active); }

.legend {
  position: absolute;
  bottom: 12px;
  left: 16px;
  font-size: 11.5px;
  color: var(--legend);
  pointer-events: none;
  letter-spacing: 0.2px;
}

/* ---------------- 题目库面板 ---------------- */
.panel {
  position: absolute;
  top: 14px;
  right: 16px;
  width: 340px;
  max-height: min(72%, 520px);
  display: flex;
  flex-direction: column;
  background: var(--panel-bg);
  border: 1px solid var(--panel-border);
  border-radius: 14px;
  box-shadow: var(--panel-shadow);
  backdrop-filter: blur(10px);
  z-index: 6;
  overflow: hidden;
}

.panel.hidden { display: none; }

.panel-head {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 12px;
  border-bottom: 1px solid var(--divider);
}

.panel-head strong { font-size: 13px; letter-spacing: 0.5px; margin-right: auto; }

.pbtn {
  appearance: none;
  border: 1px solid var(--input-border);
  background: var(--row-bg);
  color: var(--btn-text);
  font: inherit;
  font-size: 11.5px;
  line-height: 1;
  padding: 6px 9px;
  border-radius: 8px;
  cursor: pointer;
  white-space: nowrap;
  transition: background 0.14s, color 0.14s, border-color 0.14s;
}

.pbtn:hover { background: var(--btn-hover-bg); color: var(--btn-hover-text); }
.pbtn.accent { background: var(--puzzle-btn-bg); border-color: var(--puzzle-btn-bg); color: var(--puzzle-btn-text); }
.pbtn.accent:hover { background: var(--puzzle-btn-hover-bg); color: var(--puzzle-btn-hover-text); }

.panel-body {
  overflow: auto;
  padding: 8px;
  display: flex;
  flex-direction: column;
  gap: 6px;
  min-height: 60px;
}

.level-row {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 7px 8px 7px 10px;
  border-radius: 10px;
  background: var(--row-bg);
  border: 1px solid var(--row-border);
}

.level-row .ltext { flex: 1; min-width: 0; display: flex; flex-direction: column; gap: 2px; }
.level-row .lname {
  font-size: 12.5px;
  color: var(--row-name);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.level-row .lmeta { font-size: 10.5px; color: var(--row-meta); }

.level-empty {
  font-size: 11.5px;
  color: var(--empty-text);
  line-height: 1.7;
  padding: 10px;
  text-align: center;
}

.panel-foot {
  display: flex;
  flex-direction: column;
  align-items: stretch;
  gap: 6px;
  padding: 8px 10px 10px;
  border-top: 1px solid var(--divider);
}

.save-row { display: flex; gap: 6px; }

.pinput {
  flex: 1;
  min-width: 0;
  appearance: none;
  border: 1px solid var(--input-border);
  background: var(--input-bg);
  color: var(--input-text);
  font: inherit;
  font-size: 11.5px;
  padding: 6px 8px;
  border-radius: 8px;
  outline: none;
}

.pinput:focus { border-color: var(--input-focus); background: var(--input-focus-bg); }
.pinput::placeholder { color: var(--placeholder); }

.panel-tip { font-size: 10.5px; color: var(--tip-text); }

/* ---------------- 拼块盒 ---------------- */
.tray {
  display: flex;
  align-items: center;
  gap: 20px;
  padding: 12px 20px;
  min-height: 116px;
  border-top: 1px solid var(--line);
  background: var(--tray-bg);
  transition: background 0.2s, border-top-color 0.2s;
}

.tray.drop-delete {
  background:
    radial-gradient(120% 170% at 12% 0%, rgba(248, 113, 113, 0.2), transparent 62%),
    linear-gradient(180deg, #170e12, #1b1014);
  border-top-color: rgba(248, 113, 113, 0.55);
}

:root[data-theme="light"] .tray.drop-delete {
  background:
    radial-gradient(120% 170% at 12% 0%, rgba(220, 38, 38, 0.14), transparent 62%),
    linear-gradient(180deg, #fdf2f2, #fbe9e9);
  border-top-color: rgba(220, 38, 38, 0.5);
}

.tray-head { display: flex; flex-direction: column; gap: 5px; flex: none; }
.tray-title { font-size: 13px; font-weight: 600; letter-spacing: 0.6px; }
.tray-sub { font-size: 11px; color: var(--tray-sub); line-height: 1.55; }

.tray.drop-delete .tray-title::after { content: "松手删除"; margin-left: 6px; color: var(--danger-text); font-weight: 500; }
.tray.drop-delete .tray-sub { color: var(--danger-text); opacity: 0.8; }

.tray.puzzle-mode .tray-slot { opacity: 0.3; pointer-events: none; filter: none; }
.tray.puzzle-mode .tray-title::after { content: "拼图中"; margin-left: 6px; color: var(--puzzle-btn-text); font-weight: 500; }

.tray-slot {
  position: relative;
  display: grid;
  place-items: center;
  width: 90px;
  height: 90px;
  flex: none;
  border: 1px dashed var(--slot-border);
  border-radius: 16px;
  background: var(--slot-bg);
  transition: border-color 0.15s, background 0.15s;
}

.tray-slot:hover { border-color: var(--slot-hover-border); background: var(--slot-hover-bg); }

.tray-item {
  width: 76px;
  height: 76px;
  cursor: grab;
  touch-action: none;
  user-select: none;
  -webkit-user-select: none;
  filter: drop-shadow(var(--tray-shadow));
  transition: transform 0.12s;
}

.tray-item:hover { transform: scale(1.05) rotate(-2deg); }
.tray-item:active { cursor: grabbing; transform: scale(0.98); }

.tray-item svg { width: 100%; height: 100%; display: block; overflow: visible; }

#trayPoly {
  fill: var(--poly-fill);
  fill-opacity: 0.95;
  stroke: var(--poly-stroke);
  stroke-width: 3;
  stroke-linejoin: round;
}

.tray-tip {
  font-size: 11.5px;
  color: var(--tray-tip);
  line-height: 1.65;
  max-width: 560px;
  margin: 0;
}

.tray-tip b { color: var(--tray-tip-em); font-weight: 600; }

@media (max-width: 780px) {
  .tray-tip { display: none; }
  .brand-text span { display: none; }
  .tools { gap: 4px; }
  .tools button { padding: 6px 7px; font-size: 11px; }
}