:root{--bg:#f7f5ee;--panel:#fffdf7;--ink:#222;--muted:#667085;--line:#ddd3c1;--accent:#2f6f5e;--accent2:#9a5b2e;--danger:#b42318;--good:#027a48;}
*{box-sizing:border-box}body{margin:0;font-family:system-ui,-apple-system,"Segoe UI",sans-serif;background:var(--bg);color:var(--ink);line-height:1.75}.site-header{background:#fff;border-bottom:1px solid var(--line);position:sticky;top:0;z-index:10}.header-inner{max-width:1120px;margin:auto;padding:14px 18px;display:flex;gap:18px;align-items:center;justify-content:space-between}.brand a{font-weight:800;color:var(--ink);text-decoration:none;font-size:1.1rem}.nav{display:flex;gap:12px;flex-wrap:wrap}.nav a{color:#263238;text-decoration:none;font-weight:650;font-size:.95rem}.nav a:hover{text-decoration:underline}.wrap{max-width:1120px;margin:auto;padding:22px 18px}.hero{background:linear-gradient(135deg,#fffdf7,#e9f5ef);border:1px solid var(--line);border-radius:18px;padding:28px;margin:12px 0 22px}.hero h1{font-size:clamp(1.7rem,4vw,3rem);line-height:1.15;margin:.2em 0}.hero p{max-width:760px;color:#344054}.grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(230px,1fr));gap:16px}.card,.panel{background:var(--panel);border:1px solid var(--line);border-radius:16px;padding:18px;box-shadow:0 2px 10px rgba(0,0,0,.03)}.card h2,.panel h2{margin-top:0}.button,button{display:inline-flex;align-items:center;gap:6px;border:0;border-radius:999px;padding:10px 16px;background:var(--accent);color:#fff;text-decoration:none;font-weight:700;cursor:pointer}.button.secondary,button.secondary{background:#475467}.button.light{background:#fff;color:var(--accent);border:1px solid var(--accent)}button:disabled{opacity:.5;cursor:not-allowed}.ad-slot{border:1px dashed #b8b0a1;border-radius:12px;min-height:90px;width:100%;max-width:728px;margin:18px auto;display:grid;place-items:center;background:#fff;color:#666;font-size:.9rem;overflow:hidden}.question{padding:14px;border:1px solid var(--line);border-radius:12px;margin:12px 0;background:#fff}.choices{display:grid;gap:8px;margin-top:8px}.choice{background:#f6f8fa;border:1px solid #d0d5dd;color:#182230;border-radius:12px;text-align:left}.choice.selected{outline:3px solid #98c9b6}.answer{border-left:4px solid var(--accent);background:#f7fffb;padding:10px 14px;margin:10px 0;border-radius:8px}.meta{color:var(--muted);font-size:.95rem}.status{font-weight:700}.good{color:var(--good)}.danger{color:var(--danger)}.board{display:grid;margin:12px auto;max-width:min(92vw,520px);background:#2f6f5e;border:8px solid #1f493f;border-radius:10px;overflow:hidden}.cell{aspect-ratio:1;border:1px solid rgba(255,255,255,.25);background:#2f6f5e;display:grid;place-items:center;cursor:pointer}.stone{width:72%;height:72%;border-radius:50%;box-shadow:inset 0 2px 5px rgba(255,255,255,.35),0 2px 3px rgba(0,0,0,.3)}.black{background:#111}.white{background:#f4f4f4}.piece-x,.piece-o{font-size:clamp(20px,5vw,38px);font-weight:900}.piece-x{color:#111}.piece-o{color:#fff}.gomoku .cell{background:#d9aa68;border-color:#986d32}.controls{display:flex;gap:10px;flex-wrap:wrap;align-items:center;margin:12px 0}.result{font-size:1.1rem;font-weight:800}.site-footer{border-top:1px solid var(--line);margin-top:40px;background:#fff}.site-footer .wrap{display:flex;gap:12px;flex-wrap:wrap;justify-content:space-between}.site-footer a{color:#475467}.counter{font-family:ui-monospace,Menlo,Consolas,monospace;background:#111;color:#50fa7b;border-radius:12px;padding:10px 14px;display:inline-block}.small{font-size:.9rem}.kbd{font-family:ui-monospace,Menlo,Consolas,monospace;background:#f2f4f7;border:1px solid #d0d5dd;border-radius:6px;padding:2px 6px}input,select,textarea{width:100%;border:1px solid #d0d5dd;border-radius:12px;padding:10px;font:inherit}label{font-weight:700;display:block;margin-top:10px}@media(max-width:720px){.header-inner{display:block}.nav{margin-top:10px}.wrap{padding:16px 12px}.hero{padding:20px}}


.stock-table{display:grid;gap:8px}.stock-head,.stock-row{display:grid;grid-template-columns:1.5fr 1fr .8fr 1.5fr;gap:10px;align-items:center;padding:10px;border-bottom:1px solid var(--line);background:#fff;border-radius:10px}.stock-head{background:#f2f4f7}.mini-table{width:100%;border-collapse:collapse;background:#fff}.mini-table th,.mini-table td{border:1px solid var(--line);padding:8px;text-align:left}@media(max-width:720px){.stock-head,.stock-row{grid-template-columns:1fr}.stock-row span{display:block}.stock-row button{margin-top:6px}}


/* game stability update */
.game-hero .game-toolbar{display:flex;gap:10px;flex-wrap:wrap;align-items:center;margin:12px 0}.score-row{display:flex;gap:10px;flex-wrap:wrap;margin-top:10px}.score-pill{display:inline-flex;align-items:center;gap:6px;border:1px solid var(--line);border-radius:999px;padding:6px 12px;background:#fff;font-weight:800}.black-pill{color:#111}.white-pill{color:#555}.game-board-wrap{overflow:auto;max-width:100%;padding:4px}.board.othello{max-width:min(92vw,560px)}.board.gomoku{max-width:min(94vw,680px)}.cell{touch-action:manipulation;min-width:0}.cell.hint::after{content:"";width:28%;height:28%;border-radius:50%;background:rgba(255,255,255,.55);box-shadow:0 0 0 2px rgba(0,0,0,.15)}.gomoku .piece-o{color:#fff;text-shadow:0 1px 3px rgba(0,0,0,.75)}.gomoku .piece-x{color:#111;text-shadow:0 1px 2px rgba(255,255,255,.35)}.status{min-height:1.5em}.stock-row button{margin:2px 4px 2px 0}.stock-row small{color:var(--muted)}
@media(max-width:520px){.board.gomoku{min-width:520px}.game-board-wrap{border:1px solid var(--line);border-radius:12px;background:#fff}.stock-row button{width:100%;justify-content:center}}

.board .cell:disabled{cursor:not-allowed;opacity:.92}

/* question mode update 20260619i */
.mode-panel{margin:12px 0 18px}.button.active,button.active{box-shadow:0 0 0 3px rgba(46,125,90,.25);outline:2px solid var(--accent)}.muted{color:var(--muted)}


/* board visual fix 20260619i: legal moves are highlighted by square color only */
.board{gap:0}
.board .cell{
  border-radius:0 !important;
  padding:0 !important;
  margin:0 !important;
  min-width:0;
  width:100%;
  aspect-ratio:1/1;
  background:#2f6f5e;
  border:1px solid rgba(255,255,255,.22);
  display:grid;
  place-items:center;
  box-shadow:none !important;
  color:inherit;
}
.board .cell:hover{background:#3b806d}
.board .cell.hint{background:#5a9b83}
.board .cell.hint::after{content:none !important;display:none !important}
.board .cell:disabled{opacity:.96}
.board .stone{
  display:block;
  width:68%;
  height:68%;
  border-radius:50%;
  box-shadow:inset 0 2px 5px rgba(255,255,255,.35),0 2px 4px rgba(0,0,0,.35);
}
.board .stone.black{background:#111}
.board .stone.white{background:#f5f5f5}
.board.gomoku{
  background:#2f6f5e;
  border-color:#1f493f;
}
.board.gomoku .cell{
  background:#2f6f5e;
  border-color:rgba(255,255,255,.18);
}
.board.gomoku .cell:hover{background:#3b806d}
.board.gomoku .stone{width:62%;height:62%}
.board.gomoku .last-move{background:#4b927c}
.board.othello .cell.hint{background:#5a9b83}

.ad-slot iframe,.ad-slot img{max-width:100%!important;}


/* game mode/difficulty/result update 20260619i */
.inline-control{display:inline-flex;align-items:center;gap:8px;margin:0 0 0 2px;font-weight:800;background:#fff;border:1px solid var(--line);border-radius:999px;padding:6px 10px;color:#182230}
.inline-control select{width:auto;min-width:72px;border-radius:999px;padding:6px 10px;background:#fff;color:#182230}
.game-result{max-width:min(94vw,720px);margin:12px auto;padding:14px 16px;border:2px solid var(--accent);border-radius:16px;background:#f7fffb;display:flex;justify-content:space-between;gap:14px;align-items:center;box-shadow:0 8px 24px rgba(0,0,0,.08)}
.game-result.hidden{display:none!important}
.game-result strong{display:block;font-size:1.15rem;color:#103b31}.game-result p{margin:4px 0 0;color:#344054}.result-actions{display:flex;gap:8px;flex-wrap:wrap;justify-content:flex-end}.game-toolbar select:disabled{opacity:.45}.board.gomoku .cell,.board.othello .cell{border-radius:0!important}
@media(max-width:640px){.game-result{display:block}.result-actions{margin-top:10px}.result-actions button{width:100%;justify-content:center}.inline-control{width:100%;justify-content:space-between}.inline-control select{flex:0 0 92px}}


/* minesweeper + yearly question update 20260619i */
.minesweeper-board{display:grid;gap:2px;background:#1f493f;border:8px solid #1f493f;border-radius:10px;width:max-content;max-width:none;margin:12px auto;touch-action:manipulation}
.ms-cell{width:34px;height:34px;border:1px solid rgba(255,255,255,.18);border-radius:4px;background:#2f6f5e;color:#fff;font-weight:900;display:grid;place-items:center;padding:0;line-height:1;cursor:pointer;user-select:none}
.ms-cell:hover{background:#3b806d}.ms-cell.open{background:#e9dfc6;color:#1f2937;cursor:default}.ms-cell.flag{background:#5a9b83;color:#fff}.ms-cell.mine{background:#b42318;color:#fff}.ms-cell.n1{color:#175cd3}.ms-cell.n2{color:#067647}.ms-cell.n3{color:#b42318}.ms-cell.n4{color:#3538cd}.ms-cell.n5{color:#9e3a1d}.ms-cell.n6{color:#0e9384}.ms-cell.n7{color:#111}.ms-cell.n8{color:#475467}
.inline-control{display:inline-flex;gap:8px;align-items:center}.inline-control select{width:auto;min-width:110px}.game-page .panel{overflow:hidden}.game-board-wrap{overflow:auto;-webkit-overflow-scrolling:touch}
@media(max-width:640px){.ms-cell{width:30px;height:30px}.minesweeper-board{border-width:6px}}