*{margin:0;padding:0;box-sizing:border-box}
:root{--bg:#f7f8fa;--card:#fff;--primary:#2563eb;--primary-hover:#1d4ed8;--secondary:#6b7280;--secondary-hover:#4b5563;--border:#e5e7eb;--text:#1f2937;--heading:#111827;--muted:#6b7280;--error:#dc2626;--success:#16a34a;--code-bg:#fafbfc}
html{font-size:16px}
body{font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,Helvetica,Arial,sans-serif;background:var(--bg);color:var(--text);line-height:1.65}
.container{max-width:1100px;margin:0 auto;padding:24px 20px 60px}
.brand-header{display:flex;align-items:center;margin:12px 0 24px}
.brand-header a{font-size:18px;font-weight:700;color:var(--primary);text-decoration:none}
.brand-header a:hover{text-decoration:underline}
.brand-header .brand-desc{color:#666;margin-left:8px}
.back-link{display:inline-block;margin-bottom:20px;color:var(--primary);text-decoration:none;font-size:14px;font-weight:500}
.back-link:hover{text-decoration:underline}
h1{font-size:28px;line-height:1.2;margin-bottom:12px;color:var(--heading);font-weight:700}
h2{font-size:20px;line-height:1.3;margin:28px 0 12px;color:var(--heading);font-weight:600}
h3{font-size:16px;margin-bottom:6px;color:var(--heading)}
p{margin-bottom:12px}
.desc{color:var(--muted);margin-bottom:24px;font-size:15px}
.privacy-badge{display:inline-block;background:#ecfdf5;color:#065f46;font-size:12px;padding:2px 10px;border-radius:12px;font-weight:500;margin-left:8px;vertical-align:middle}
.tool-area{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin-bottom:16px}
.tool-area.single{grid-template-columns:1fr}
.pane{background:var(--card);border:1px solid var(--border);border-radius:8px;padding:14px;box-shadow:0 1px 2px rgba(0,0,0,.04);transition:box-shadow .15s}
.pane:hover{box-shadow:0 2px 6px rgba(0,0,0,.06)}
.pane label{display:block;font-size:13px;font-weight:600;margin-bottom:8px;color:var(--secondary);text-transform:uppercase;letter-spacing:.03em}
textarea,.expr-input{width:100%;min-height:280px;font-family:'Consolas','Monaco','Courier New',monospace;font-size:13px;line-height:1.5;padding:10px;border:1px solid var(--border);border-radius:6px;resize:vertical;background:var(--code-bg);color:var(--text);outline:none;transition:border-color .15s}
textarea:focus,.expr-input:focus{border-color:var(--primary)}
.expr-input{min-height:48px;resize:none}
#output{background:var(--code-bg);color:#0f172a}
.buttons{display:flex;gap:12px;align-items:center;margin-bottom:16px;flex-wrap:wrap}
button{padding:10px 24px;border:none;border-radius:6px;font-size:14px;font-weight:600;cursor:pointer;transition:background .15s;font-family:inherit}
.btn-primary{background:var(--primary);color:#fff}
.btn-primary:hover{background:var(--primary-hover)}
.btn-secondary{background:var(--secondary);color:#fff}
.btn-secondary:hover{background:var(--secondary-hover)}
#status{font-size:13px;margin-left:8px;font-weight:500}
.status-ok{color:var(--success)}
.status-error{color:var(--error)}
.related{display:flex;flex-wrap:wrap;gap:10px;margin-top:8px}
.related a{display:inline-block;padding:8px 14px;background:#fff;border:1px solid var(--border);border-radius:6px;color:var(--primary);text-decoration:none;font-size:13px;font-weight:500;transition:box-shadow .15s,border-color .15s}
.related a:hover{box-shadow:0 2px 6px rgba(0,0,0,.08);border-color:var(--primary)}
.tools-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(260px,1fr));gap:16px;margin-top:24px}
.tool-card{display:block;padding:20px;background:#fff;border:1px solid var(--border);border-radius:8px;text-decoration:none;color:var(--text);transition:box-shadow .15s,transform .15s,border-color .15s}
.tool-card:hover{box-shadow:0 4px 12px rgba(0,0,0,.08);transform:translateY(-2px);border-color:var(--primary)}
.tool-card h3{color:var(--primary);margin-bottom:6px;font-size:16px;font-weight:600}
.tool-card p{font-size:13px;color:var(--muted);margin:0;line-height:1.5}
.feature-list{padding-left:20px}
.feature-list li{margin-bottom:6px}
.feature-list li::marker{color:var(--primary)}
code{background:var(--code-bg);padding:2px 6px;border-radius:4px;font-size:13px;font-family:'Consolas','Monaco',monospace;border:1px solid var(--border)}
pre{background:var(--code-bg);padding:12px;border-radius:6px;overflow-x:auto;border:1px solid var(--border);margin-bottom:12px}
pre code{background:none;border:none;padding:0}
footer{margin-top:40px;padding-top:20px;border-top:1px solid var(--border);color:var(--muted);font-size:13px;text-align:center}
@media (max-width:768px){.tool-area{grid-template-columns:1fr}h1{font-size:24px}h2{font-size:18px}.container{padding:16px 12px 40px}textarea,.expr-input{min-height:200px}.tools-grid{grid-template-columns:1fr}.buttons{flex-direction:column;align-items:stretch}button{width:100%}}

.ad-slot{min-height:15px;margin-top:40px;margin-bottom:32px}

/* ===== Form controls (shared by tool pages) ===== */
.field{margin-bottom:14px}
.field:last-child{margin-bottom:0}
.field label{display:block;font-size:13px;font-weight:600;margin-bottom:6px;color:var(--secondary);text-transform:uppercase;letter-spacing:.03em}
select,input[type=text],input[type=number],input[type=date]{width:100%;font-family:inherit;font-size:14px;padding:10px;border:1px solid var(--border);border-radius:6px;background:#fff;color:var(--text);outline:none;transition:border-color .15s}
select:focus,input[type=text]:focus,input[type=number]:focus,input[type=date]:focus{border-color:var(--primary)}
.form-grid{display:grid;grid-template-columns:1fr 1fr;gap:14px}
.result-box{min-height:120px;padding:12px;background:var(--code-bg);border:1px solid var(--border);border-radius:6px;font-size:15px;line-height:1.7;color:var(--text);white-space:pre-wrap}
.ref-list{min-height:80px;max-height:220px;overflow:auto;font-size:12px;line-height:1.6;white-space:pre-wrap;padding:10px;background:var(--code-bg);border:1px solid var(--border);border-radius:6px;color:var(--muted)}
table.result{width:100%;border-collapse:collapse;font-size:14px;margin-bottom:12px}
table.result th,table.result td{border:1px solid var(--border);padding:8px 10px;text-align:left}
table.result th{background:var(--code-bg);font-weight:600}
@media (max-width:768px){.form-grid{grid-template-columns:1fr}}

/* ===== Floating topbar + language dropdown ===== */
.topbar{position:sticky;top:0;z-index:100;display:flex;align-items:center;gap:10px;flex-wrap:wrap;padding:10px 16px;background:#fff;border-bottom:1px solid #e4e8f0;box-shadow:0 1px 4px rgba(20,30,60,.05);}
.topbar a{color:#3b82f6;text-decoration:none;font-size:13px;font-weight:600;}
.topbar a:hover{text-decoration:underline;}
.topbar .divider{color:#d7deea;font-size:13px;}
.topbar .brand-name{font-weight:700;font-size:15px;color:#1f2430;letter-spacing:.3px;text-decoration:none;}
.topbar .brand-name span{color:#3b82f6;}
.spacer{flex:1;}
.lang-dropdown{position:relative;}
.lang-dropdown summary{list-style:none;cursor:pointer;font-size:13px;font-weight:600;color:#39435a;background:#fff;border:1px solid #dde3ee;border-radius:9px;padding:7px 12px;display:inline-flex;align-items:center;gap:6px;}
.lang-dropdown summary::-webkit-details-marker{display:none;}
.lang-dropdown summary::after{content:'\25BE';font-size:10px;color:#8b93a7;margin-left:2px;}
.lang-menu{position:absolute;right:0;top:calc(100% + 6px);background:#fff;border:1px solid #e4e8f0;border-radius:9px;box-shadow:0 6px 18px rgba(20,30,60,.12);overflow:hidden;min-width:140px;z-index:200;display:flex;flex-direction:column;}
.lang-menu a{display:block;padding:9px 14px;color:#39435a;text-decoration:none;font-size:13px;font-weight:500;}
.lang-menu a:hover{background:#f4f7fd;color:#3b82f6;}
.lang-menu a[aria-current="true"]{background:#eef4ff;color:#2563eb;font-weight:700;}
@media(max-width:768px){.topbar{padding:8px 12px;}.topbar .brand-name{font-size:14px;}}

/* Legal links (footer) */
.legal-links{margin-top:6px;font-size:12px}
.legal-links a{margin:0 5px}

/* Chinese layout fine-tuning */
:lang(zh) h1{letter-spacing:.02em}

/* ===== Sudoku grid ===== */
.sudoku{border-collapse:collapse;margin:8px 0}
.sudoku td{width:34px;height:34px;text-align:center;vertical-align:middle;font-size:17px;border:1px solid var(--border)}
.sudoku td.given{font-weight:700;color:var(--heading)}
.sudoku td.answer{color:var(--primary);font-weight:600}
.sudoku td.br{border-right:2px solid #94a3b8}
.sudoku td.bb{border-bottom:2px solid #94a3b8}

/* ===== Word search grid ===== */
.ws-grid{border-collapse:collapse;margin:8px 0}
.ws-grid td{width:26px;height:26px;text-align:center;font-size:14px;border:1px solid var(--border);font-family:'Consolas','Monaco',monospace}
.ws-grid td.hit{background:#ecfdf5;color:#065f46;font-weight:700}
.ws-words{display:flex;flex-wrap:wrap;gap:6px 16px;margin:8px 0;padding:0;list-style:none}
.ws-words li{font-size:14px;font-family:'Consolas','Monaco',monospace}

/* ===== Tracing sheet ===== */
.trace-sheet{margin:8px 0}
.trace-row{display:flex;align-items:center;gap:14px;padding:6px 0;border-bottom:1px dashed var(--border)}
.trace-cell{font-size:34px;line-height:1;font-family:'Segoe UI',Arial,sans-serif}
.trace-model{color:var(--heading);font-weight:700}
.trace-faint{color:#cbd5e1}
.trace-outline{color:#e2e8f0;-webkit-text-stroke:1px #94a3b8}

/* ===== Print ===== */
@media print{
  .topbar,.buttons,.related,footer,.ad-slot,h1,h2,h3,.desc,.no-print{display:none!important}
  .tool-area{grid-template-columns:1fr!important}
  .pane{border:0;box-shadow:none;padding:0}
  body{background:#fff}
}

/* ===== Certificate ===== */
.certificate{border:4px double #c7d2fe;border-radius:6px;padding:28px;text-align:center;background:#fff;margin:8px 0}
.certificate .cert-title{font-size:22px;font-weight:700;color:var(--heading);letter-spacing:.04em;margin-bottom:12px}
.certificate .cert-lead{font-size:13px;color:var(--muted);margin-bottom:4px}
.certificate .cert-name{font-size:28px;font-weight:700;color:var(--primary);margin:6px 0 12px;word-break:break-word}
.certificate .cert-award{font-size:16px;margin-bottom:20px;word-break:break-word}
.certificate .cert-foot{display:flex;justify-content:space-around;gap:20px;margin-top:20px;font-size:13px;color:var(--muted)}
.certificate .cert-line{border-top:1px solid var(--border);padding-top:6px;min-width:120px;word-break:break-word}

/* Classroom timer display */
.timer-display{font-family:'Consolas','Monaco',monospace;font-size:56px;font-weight:700;text-align:center;color:var(--heading);padding:18px 0;letter-spacing:.04em}

/* Answer sheet */
.answer-sheet-head{display:flex;gap:24px;flex-wrap:wrap;margin-bottom:12px;font-size:14px;color:var(--text)}
.answer-sheet{display:grid;grid-template-columns:repeat(5,1fr);gap:8px}
.answer-cell{border:1px solid var(--border);border-radius:6px;padding:6px 8px;font-size:13px;background:#fff}
.answer-cell .qnum{font-weight:700;color:var(--heading);margin-right:6px}
.answer-cell .opts span{display:inline-block;min-width:16px;margin-right:4px}
@media (max-width:768px){.answer-sheet{grid-template-columns:repeat(3,1fr)}}

/* Test paper and printable text blocks */
.paper{white-space:pre-wrap;font-size:14px;line-height:1.7;color:var(--text)}
.bingo-wrap{display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:16px}
.bingo-title{font-weight:700;color:var(--heading);margin:6px 0}
.bingo-card td{height:30px;font-size:13px;text-align:center}

/* Matching game */
.match-cols{display:flex;gap:32px;flex-wrap:wrap;margin:8px 0}
.match-col{flex:1;min-width:180px}
.match-col p{margin:0 0 6px}
.match-item{margin:4px 0;font-size:14px}

/* Memory match cards */
.memory-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(140px,1fr));gap:10px;margin:8px 0}
.memory-card{border:1px dashed var(--border);border-radius:6px;padding:14px 8px;text-align:center;font-size:14px;background:#fff;word-break:break-word}

/* Pregnancy nutrition checklist */
.check-list label{display:block;text-transform:none;letter-spacing:0;font-weight:500;color:var(--text);font-size:14px;margin-bottom:6px}
.check-list input{margin-right:8px}

/* ===== Spinner wheel ===== */
.svg-wheel{width:100%;max-width:440px;height:auto;display:block;margin:8px auto}
.svg-wheel text{font-size:14px;font-weight:600;fill:#fff;pointer-events:none}

/* ===== Dice ===== */
.dice-row{display:flex;flex-wrap:wrap;gap:10px;margin:6px 0 12px}
.die{display:inline-flex;align-items:center;justify-content:center;width:46px;height:46px;background:#fff;border:1px solid var(--border);border-radius:8px;font-size:20px;font-weight:700;color:var(--heading);box-shadow:0 1px 3px rgba(0,0,0,.08)}
.dice-total{font-size:18px;font-weight:700;color:var(--heading);margin-bottom:4px}
.dice-each{font-size:13px;color:var(--muted);margin:0}

/* ===== Word search ===== */
.ws-wrap{overflow:auto}
.ws-title{font-weight:700;color:var(--heading);margin:12px 0 6px}
.ws-grid td{width:26px;height:26px;text-align:center;font-size:14px;border:1px solid var(--border);font-family:'Consolas','Monaco',monospace}
.ws-grid td.hit{background:#ecfdf5;color:#065f46;font-weight:700}

/* ===== Matching game ===== */
.match-head{font-weight:700;color:var(--heading);margin:0 0 6px}
.match-key{margin-top:12px}

/* ===== Board game ===== */
.board-wrap{display:grid;gap:6px;margin:8px 0}
.board-cell{display:flex;flex-direction:column;align-items:center;justify-content:center;min-height:56px;padding:4px;background:#fff;border:1px solid var(--border);border-radius:8px;text-align:center;font-size:11px;color:var(--muted)}
.board-cell.board-empty{background:transparent;border:0}
.board-num{font-size:16px;font-weight:700;color:var(--heading)}
.board-tag{font-size:10px;line-height:1.2;margin-top:2px}
.board-start{background:#ecfdf5;border-color:#86efac}
.board-finish{background:#fef2f2;border-color:#fca5a5}
.board-bonus{background:#eff6ff;border-color:#93c5fd}
.board-setback{background:#fff7ed;border-color:#fdba74}

/* ===== Card game ===== */
.card-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(96px,1fr));gap:8px;margin:8px 0}
.game-card{display:flex;align-items:center;justify-content:center;min-height:64px;padding:8px;background:#fff;border:1px dashed var(--border);border-radius:8px;text-align:center;font-size:14px;font-weight:600;color:var(--heading);word-break:break-word}

/* ===== Random draw / word guess / quiz lists ===== */
.draw-wrap{margin:6px 0}
.draw-list{margin:6px 0;padding-left:22px}
.draw-list li{margin-bottom:4px;font-size:14px}
.quiz-list{margin:6px 0;padding-left:22px}
.quiz-list li{margin-bottom:12px}
.quiz-q{font-weight:600;color:var(--heading)}
.quiz-opt{font-size:13px;color:var(--muted);margin-left:4px}