:root {
  --bg: #f4f1ea;
  --bg-grad-a: #fef6e4;
  --bg-grad-b: #e8f0fe;
  --card-bg: #ffffff;
  --text: #2b2b33;
  --text-sub: #6b6b78;
  --accent: #ff6b6b;
  --accent2: #4a7dff;
  --line: #e2ddd0;
  --cell-bg: #fbfaf6;
  --cell-hover: #f0eee6;
  --block-bg: #d8d4c8;
  --shadow: 0 4px 14px rgba(0,0,0,0.08);
  --win-glow: #ffd93d;
  --radius: 16px;
  --font: "Hiragino Maru Gothic ProN","Yu Gothic",-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;
}

[data-theme="dark"] {
  --bg: #16161f;
  --bg-grad-a: #1b1b28;
  --bg-grad-b: #14141d;
  --card-bg: #21212e;
  --text: #f0f0f5;
  --text-sub: #9c9cae;
  --accent: #ff7b7b;
  --accent2: #6f95ff;
  --line: #33333f;
  --cell-bg: #292938;
  --cell-hover: #33334480;
  --block-bg: #3a3a48;
  --shadow: 0 4px 18px rgba(0,0,0,0.4);
  --win-glow: #ffe066;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: var(--font);
  background: radial-gradient(circle at 20% 0%, var(--bg-grad-a), var(--bg-grad-b) 60%, var(--bg));
  color: var(--text);
  min-height: 100vh;
  transition: background 0.3s, color 0.3s;
  padding-bottom: 40px;
}

.app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 20px;
  max-width: 720px;
  margin: 0 auto;
}

.logo {
  margin: 0;
  font-size: 1.5rem;
  font-weight: 800;
  display: flex;
  align-items: center;
  gap: 6px;
}
.logo span { color: var(--accent); }
.logo span:last-child { color: var(--accent2); }

.header-btns { display: flex; gap: 8px; }
.icon-btn {
  border: none;
  background: var(--card-bg);
  box-shadow: var(--shadow);
  width: 40px; height: 40px;
  border-radius: 50%;
  font-size: 1.1rem;
  cursor: pointer;
  transition: transform 0.15s;
}
.icon-btn:hover { transform: scale(1.08); }
.icon-btn:active { transform: scale(0.95); }

.screen { max-width: 720px; margin: 0 auto; padding: 8px 16px 24px; }
.screen.hidden { display: none; }

.setup-card {
  background: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 18px 18px 20px;
  margin-bottom: 16px;
}
.setup-card h2 {
  margin: 0 0 12px;
  font-size: 1rem;
  color: var(--text-sub);
}

.choice-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 10px;
}

.choice-btn {
  border: 2px solid var(--line);
  background: var(--cell-bg);
  border-radius: 12px;
  padding: 12px 10px;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  gap: 4px;
  text-align: left;
  transition: all 0.15s;
  color: var(--text);
  font-family: inherit;
}
.choice-btn:hover { border-color: var(--accent2); transform: translateY(-2px); }
.choice-btn.selected {
  border-color: var(--accent);
  background: linear-gradient(135deg, var(--accent)22, var(--accent2)22);
  box-shadow: 0 0 0 2px var(--accent) inset;
}
.choice-title { font-weight: 700; font-size: 0.95rem; }
.choice-sub { font-size: 0.75rem; color: var(--text-sub); }

.start-btn {
  display: block;
  width: 100%;
  padding: 16px;
  font-size: 1.1rem;
  font-weight: 800;
  border: none;
  border-radius: 14px;
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  color: #fff;
  cursor: pointer;
  box-shadow: var(--shadow);
  transition: transform 0.15s, opacity 0.15s;
}
.start-btn:disabled { opacity: 0.4; cursor: not-allowed; }
.start-btn:not(:disabled):hover { transform: translateY(-2px); }
.start-btn:not(:disabled):active { transform: translateY(0); }

.stats-preview {
  text-align: center;
  color: var(--text-sub);
  font-size: 0.85rem;
  margin-top: 14px;
  line-height: 1.8;
}

/* game screen */
.game-topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 10px;
}
.text-btn {
  background: none;
  border: none;
  color: var(--accent2);
  font-weight: 700;
  cursor: pointer;
  font-size: 0.9rem;
  padding: 6px;
}
.mode-badge {
  background: var(--card-bg);
  box-shadow: var(--shadow);
  padding: 6px 14px;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--text-sub);
}

.scoreboard {
  display: flex;
  justify-content: center;
  gap: 24px;
  background: var(--card-bg);
  border-radius: 14px;
  box-shadow: var(--shadow);
  padding: 12px;
  margin-bottom: 10px;
}
.score-item { text-align: center; }
.score-name { font-size: 0.8rem; color: var(--text-sub); }
.score-num { font-size: 1.4rem; font-weight: 800; }

.turn-indicator {
  text-align: center;
  font-weight: 800;
  font-size: 1.05rem;
  margin-bottom: 10px;
  min-height: 1.4em;
}
.turn-indicator.p1 { color: var(--accent); }
.turn-indicator.p2 { color: var(--accent2); }

.timeattack-bar-wrap {
  height: 8px;
  background: var(--line);
  border-radius: 4px;
  overflow: hidden;
  margin-bottom: 10px;
}
.timeattack-bar-wrap.hidden { display: none; }
.timeattack-bar {
  height: 100%;
  width: 100%;
  background: linear-gradient(90deg, #4caf50, #ffeb3b, #ff5252);
  transition: width 0.1s linear;
}

.wild-symbol-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  margin-bottom: 10px;
  font-size: 0.9rem;
}
.wild-symbol-toggle.hidden { display: none; }
.wild-symbol-btn {
  border: 2px solid var(--line);
  background: var(--cell-bg);
  color: var(--text);
  border-radius: 8px;
  padding: 6px 14px;
  font-size: 1.1rem;
  font-weight: 800;
  cursor: pointer;
}
.wild-symbol-btn.active { border-color: var(--accent); background: var(--accent)22; }

.stack-tray {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  margin-bottom: 10px;
  font-size: 0.9rem;
}
.stack-tray.hidden { display: none; }
.stack-size-btn {
  border: 2px solid var(--line);
  background: var(--cell-bg);
  color: var(--text);
  border-radius: 8px;
  padding: 6px 12px;
  font-size: 0.85rem;
  font-weight: 800;
  cursor: pointer;
}
.stack-size-btn.active { border-color: var(--accent); background: var(--accent)22; }
.stack-size-btn:disabled { opacity: 0.35; cursor: not-allowed; }

.board-wrap {
  display: flex;
  justify-content: center;
  margin-bottom: 14px;
}
.board {
  display: grid;
  gap: 6px;
  width: min(90vw, 420px);
  aspect-ratio: 1;
}
.cell {
  background: var(--cell-bg);
  border: none;
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  cursor: pointer;
  color: var(--text);
  transition: background 0.12s, transform 0.08s;
  position: relative;
  font-size: calc(min(90vw, 420px) / var(--size) * 0.45);
}
.cell:hover:not(:disabled) { background: var(--cell-hover); }
.cell:active:not(:disabled) { transform: scale(0.93); }
.cell:disabled { cursor: default; }
.cell.sym-X { color: var(--accent); }
.cell.sym-O { color: var(--accent2); }
.cell.blocked { background: repeating-linear-gradient(45deg, var(--block-bg), var(--block-bg) 6px, transparent 6px, transparent 12px); cursor: not-allowed; }
.cell.win { background: var(--win-glow); animation: pop 0.4s; }
.cell.gravity-col:hover:not(:disabled) { background: var(--cell-hover); box-shadow: 0 -2px 0 var(--accent2) inset; }
.cell.placed { animation: pop 0.25s; }
.cell .piece-symbol { display: inline-block; transition: transform 0.15s; }
.cell .stack-badge {
  position: absolute;
  bottom: 3px; right: 6px;
  font-size: 0.55rem;
  font-weight: 800;
  opacity: 0.65;
  background: var(--card-bg);
  border-radius: 6px;
  padding: 0 4px;
}
.cell.stk-3:not(.blocked) { box-shadow: 0 0 0 2px var(--accent2) inset; }

@keyframes pop {
  0% { transform: scale(0.5); }
  60% { transform: scale(1.15); }
  100% { transform: scale(1); }
}

.result-panel {
  text-align: center;
  background: var(--card-bg);
  border-radius: 16px;
  box-shadow: var(--shadow);
  padding: 20px;
}
.result-panel.hidden { display: none; }
.result-text { font-size: 1.3rem; font-weight: 800; margin-bottom: 14px; }
.result-btns { display: flex; gap: 10px; justify-content: center; flex-wrap: wrap; }
.result-btns .start-btn { width: auto; padding: 12px 28px; }

/* modal */
.modal-overlay {
  position: fixed; inset: 0;
  background: rgba(0,0,0,0.5);
  display: flex; align-items: center; justify-content: center;
  z-index: 100;
  padding: 20px;
}
.modal-overlay.hidden { display: none; }
.modal {
  background: var(--card-bg);
  border-radius: 16px;
  max-width: 560px;
  width: 100%;
  max-height: 80vh;
  overflow-y: auto;
  padding: 24px;
  position: relative;
  box-shadow: var(--shadow);
}
.modal-close {
  position: absolute; top: 12px; right: 12px;
  border: none; background: var(--cell-bg); color: var(--text);
  width: 32px; height: 32px; border-radius: 50%;
  font-size: 1.1rem; cursor: pointer;
}
.modal h2 { margin-top: 0; }
.modal h3 { margin-bottom: 6px; color: var(--accent2); }

.ach-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(140px,1fr)); gap: 8px; margin-top: 10px; }
.ach-item {
  border: 2px solid var(--line);
  border-radius: 10px;
  padding: 8px;
  font-size: 0.75rem;
  text-align: center;
  opacity: 0.4;
}
.ach-item.unlocked { opacity: 1; border-color: var(--win-glow); background: var(--win-glow)22; }
.ach-icon { font-size: 1.5rem; display: block; margin-bottom: 4px; }
.ach-progress { text-align: center; margin: 6px 0 4px; font-weight: 700; color: var(--text-sub); }

.online-text-input {
  width: 100%;
  padding: 12px 14px;
  border: 2px solid var(--line);
  border-radius: 10px;
  background: var(--cell-bg);
  color: var(--text);
  font-size: 1rem;
  font-family: inherit;
  box-sizing: border-box;
}
.online-code-input { text-align: center; font-weight: 800; font-size: 1.3rem; letter-spacing: 3px; text-transform: uppercase; }
.online-btn-row { display: flex; gap: 10px; align-items: center; margin-top: 12px; }
.online-btn-row .start-btn { flex: 1; }
#online-waiting-card { text-align: center; }
#online-waiting-card h2 { font-size: 1.05rem; }
.online-room-code {
  font-size: 2.2rem;
  font-weight: 800;
  letter-spacing: 6px;
  padding: 16px;
  margin: 10px 0;
  border: 3px dashed var(--accent2);
  border-radius: 14px;
  color: var(--accent2);
  background: var(--cell-bg);
}
.online-room-code:empty { display: none; }
.online-status-row { display: flex; align-items: center; justify-content: center; gap: 6px; font-size: 0.85rem; color: var(--text-sub); margin-top: 6px; }
.online-dot { width: 8px; height: 8px; border-radius: 50%; background: #4caf50; display: inline-block; }
.online-dot.offline { background: #bbb; }

.bgm-hint { font-size: 0.8rem; color: var(--text-sub); line-height: 1.6; }
.bgm-hint code { background: var(--cell-bg); padding: 1px 5px; border-radius: 4px; }
.bgm-controls { display: flex; gap: 10px; margin: 10px 0 14px; }
.bgm-controls .text-btn { border: 2px solid var(--line); border-radius: 20px; padding: 6px 14px; }
.bgm-controls .text-btn.active { border-color: var(--accent); background: var(--accent)22; }
.bgm-track-list { display: flex; flex-direction: column; gap: 8px; margin-bottom: 16px; }
.bgm-track-btn {
  border: 2px solid var(--line);
  background: var(--cell-bg);
  border-radius: 12px;
  padding: 10px 12px;
  text-align: left;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  gap: 2px;
  color: var(--text);
  font-family: inherit;
}
.bgm-track-btn.active { border-color: var(--accent); background: var(--accent)22; }
.bgm-track-title { font-weight: 700; font-size: 0.9rem; }
.bgm-track-desc { font-size: 0.75rem; color: var(--text-sub); }
.bgm-volume-row { display: flex; align-items: center; gap: 10px; }
.bgm-volume-row input[type="range"] { flex: 1; }
#bgm-mute-btn { border: none; background: var(--cell-bg); border-radius: 50%; width: 34px; height: 34px; cursor: pointer; font-size: 1rem; }

.changelog-entry { margin-bottom: 14px; }
.changelog-ver { font-weight: 800; color: var(--accent); }
.changelog-date { color: var(--text-sub); font-size: 0.8rem; margin-left: 8px; }
.changelog-entry ul { margin: 6px 0 0; padding-left: 20px; }

/* toast */
#toast-area {
  position: fixed;
  top: 16px; left: 50%;
  transform: translateX(-50%);
  z-index: 200;
  display: flex; flex-direction: column; gap: 8px;
  align-items: center;
  pointer-events: none;
}
.toast {
  background: var(--card-bg);
  color: var(--text);
  padding: 10px 18px;
  border-radius: 24px;
  box-shadow: var(--shadow);
  font-weight: 700;
  font-size: 0.85rem;
  border: 2px solid var(--win-glow);
  animation: toast-in 0.3s, toast-out 0.3s 2.4s forwards;
}
@keyframes toast-in { from { opacity:0; transform: translateY(-10px);} to {opacity:1; transform:translateY(0);} }
@keyframes toast-out { to { opacity:0; transform: translateY(-10px);} }

.app-footer {
  text-align: center;
  color: var(--text-sub);
  font-size: 0.75rem;
  margin-top: 30px;
  display: flex;
  gap: 10px;
  justify-content: center;
}
.app-footer a { color: var(--accent2); }

@media (max-width: 480px) {
  .logo { font-size: 1.2rem; }
  .setup-card { padding: 14px; }
}