:root {
  --bg: #060b14; --card: rgba(255,255,255,0.04);
  --border: rgba(255,255,255,0.08); --border-strong: rgba(255,255,255,0.14);
  --text: #e4eaf6; --dim: #8894b0; --faint: #586380;
  --grad: linear-gradient(135deg, #22d3ee, #6366f1, #a855f7);
  --cyan: #22d3ee; --violet: #a855f7; --indigo: #6366f1;
  --ok: #34d399; --warn: #fbbf24; --danger: #f87171;
  --radius: 16px; --radius-sm: 10px;
  --cell-size: 30px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC","Microsoft YaHei",sans-serif;
  --mono: "Cascadia Code",Consolas,monospace;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{font-family:var(--font);background:var(--bg);color:var(--text);min-height:100vh;overflow-x:hidden;line-height:1.6}
body::before{content:'';position:fixed;inset:0;z-index:-2;
  background:radial-gradient(60% 40% at 20% 0%,rgba(34,211,238,0.1),transparent 60%),
  radial-gradient(50% 40% at 85% 10%,rgba(168,85,247,0.08),transparent 60%)}
body::after{content:'';position:fixed;inset:0;z-index:-1;pointer-events:none;
  background-image:linear-gradient(rgba(255,255,255,0.03) 1px,transparent 1px),linear-gradient(90deg,rgba(255,255,255,0.03) 1px,transparent 1px);
  background-size:40px 40px;-webkit-mask-image:radial-gradient(ellipse 80% 50% at 50% 0%,#000 30%,transparent 70%);mask-image:radial-gradient(ellipse 80% 50% at 50% 0%,#000 30%,transparent 70%)}

/* Header */
header{position:sticky;top:0;z-index:100;background:rgba(6,11,20,0.82);backdrop-filter:blur(16px);border-bottom:1px solid var(--border)}
.h-inner{max-width:960px;margin:0 auto;display:flex;align-items:center;justify-content:space-between;padding:0 18px;height:56px}
.logo{display:flex;align-items:center;gap:10px;font-weight:800;font-size:18px;letter-spacing:1px}
.logo-mark{width:34px;height:34px;border-radius:8px;background:var(--grad);display:grid;place-items:center;color:#fff;font-weight:900;font-size:17px;box-shadow:0 4px 14px rgba(99,102,241,0.4)}
.user-area{display:flex;align-items:center;gap:10px}
.user-avatar{width:28px;height:28px;border-radius:50%;display:inline-grid;place-items:center;color:#fff;font-size:13px;font-weight:700}
.user-name{font-size:13px;color:var(--dim)}
.btn{display:inline-flex;align-items:center;gap:6px;padding:9px 18px;border-radius:999px;font-size:13px;font-weight:600;border:1px solid transparent;cursor:pointer;transition:all 0.2s;font-family:inherit;white-space:nowrap}
.btn-primary{background:var(--grad);color:#fff;box-shadow:0 6px 18px rgba(99,102,241,0.35)}
.btn-primary:hover{transform:translateY(-1px);box-shadow:0 8px 24px rgba(99,102,241,0.5)}
.btn-ghost{background:rgba(255,255,255,0.05);color:var(--text);border-color:var(--border)}
.btn-ghost:hover{background:rgba(255,255,255,0.1)}
.btn-sm{padding:6px 13px;font-size:12px}
.btn-danger{background:rgba(248,113,113,0.12);color:var(--danger);border-color:rgba(248,113,113,0.3)}
.btn-danger:hover{background:rgba(248,113,113,0.2)}

/* Nav tabs */
nav{max-width:960px;margin:12px auto 0;display:flex;gap:4px;padding:0 18px}
.nav-tab{flex:1;padding:11px 8px;border-radius:10px 10px 0 0;background:rgba(255,255,255,0.02);border:1px solid transparent;color:var(--dim);font-size:14px;font-weight:600;cursor:pointer;text-align:center;transition:all 0.2s;font-family:inherit;border-bottom:none}
.nav-tab:hover{color:var(--text);background:rgba(255,255,255,0.05)}
.nav-tab.active{color:#fff;background:rgba(99,102,241,0.12);border-color:rgba(99,102,241,0.25)}

.page{display:none;max-width:960px;margin:0 auto;padding:16px 18px 80px}
.page.active{display:block}

/* Game panel */
.game-panel{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);padding:20px;text-align:center}
.game-toolbar{display:flex;align-items:center;justify-content:center;gap:12px;flex-wrap:wrap;margin-bottom:12px}
.game-stats{display:flex;gap:20px;align-items:center}
.game-stats .stat{display:flex;align-items:center;gap:6px;font-size:14px;color:var(--dim)}
.game-stats .stat b{color:var(--text);font-variant-numeric:tabular-nums;min-width:28px;text-align:center}
.stat-icon{font-size:18px}

.diff-bar{display:flex;gap:8px;flex-wrap:wrap;justify-content:center;margin:12px 0}
.diff-btn{padding:7px 16px;border-radius:8px;border:1px solid var(--border);background:rgba(255,255,255,0.04);color:var(--dim);font-size:13px;font-weight:600;cursor:pointer;transition:all 0.2s;font-family:inherit}
.diff-btn:hover{border-color:var(--indigo);color:var(--text)}
.diff-btn.custom{color:var(--cyan)}

.mode-bar{display:flex;gap:6px;justify-content:center;margin-bottom:14px}
.mode-btn{padding:5px 14px;border-radius:6px;border:1px solid var(--border);background:rgba(255,255,255,0.03);color:var(--dim);font-size:12px;cursor:pointer;font-family:inherit;transition:all 0.15s}
.mode-btn.active{background:rgba(99,102,241,0.15);border-color:var(--indigo);color:#fff}
.help-bar{font-size:11px;color:var(--faint);text-align:center;margin-bottom:8px}
.help-bar span{margin:0 8px}

/* Board */
.board-wrap{overflow:auto;display:flex;justify-content:center;padding:4px}
.board{display:grid;gap:1px;user-select:none;-webkit-user-select:none}
.cell{width:var(--cell-size);height:var(--cell-size);display:grid;place-items:center;font-size:calc(var(--cell-size)*0.45);font-weight:700;cursor:pointer;border-radius:3px;background:linear-gradient(145deg,rgba(255,255,255,0.07),rgba(255,255,255,0.02));border:1px solid rgba(255,255,255,0.04);transition:all 0.1s;font-family:var(--mono)}
.cell:hover{background:rgba(99,102,241,0.15);border-color:rgba(99,102,241,0.3)}
.cell:active{transform:scale(0.92)}
.cell.revealed{background:rgba(255,255,255,0.03);border-color:rgba(255,255,255,0.02);cursor:default}
.cell.revealed:hover{background:rgba(255,255,255,0.03)}
.cell.revealed:active{transform:none}
.cell.flagged{background:rgba(251,191,36,0.08);border-color:rgba(251,191,36,0.25)}
.cell.marked{background:rgba(168,85,247,0.08);border-color:rgba(168,85,247,0.25)}
.cell.mine{background:rgba(248,113,113,0.12)}
.cell.n1{color:#4da6ff}.cell.n2{color:#34d399}.cell.n3{color:#f87171}
.cell.n4{color:#6366f1}.cell.n5{color:#ef4444}.cell.n6{color:#14b8a6}.cell.n7{color:#111}.cell.n8{color:#6b7280}

/* Result modal */
.modal-mask{position:fixed;inset:0;background:rgba(2,4,12,0.7);backdrop-filter:blur(4px);display:none;place-items:center;z-index:200;padding:20px}
.modal-mask.open{display:grid}
.modal{width:min(380px,100%);background:#111827;border:1px solid var(--border-strong);border-radius:18px;padding:30px 24px;text-align:center;box-shadow:0 30px 60px rgba(0,0,0,0.5)}
.modal h2{font-size:22px;margin:10px 0 6px}
.modal p{color:var(--dim);font-size:14px;margin:4px 0}
.modal .actions{display:flex;gap:10px;justify-content:center;margin-top:18px}

.modal .field{margin-bottom:12px;text-align:left}
.modal .field label{display:block;font-size:12px;color:var(--dim);margin-bottom:4px;font-weight:600}
.modal .field input{width:100%;padding:11px 14px;border-radius:10px;border:1px solid var(--border);background:rgba(255,255,255,0.04);color:var(--text);font-size:14px;outline:none;font-family:inherit}
.modal .field input:focus{border-color:var(--indigo);box-shadow:0 0 0 3px rgba(99,102,241,0.15)}
.modal .form-msg{font-size:12px;color:var(--danger);margin-bottom:8px;min-height:16px}
.modal-close{position:absolute;top:12px;right:14px;background:none;border:none;color:var(--dim);font-size:20px;cursor:pointer}
.cust-grid{display:flex;gap:10px;flex-wrap:wrap}
.cust-grid .field{flex:1;min-width:80px}

/* Leaderboard */
.lb-controls{display:flex;align-items:center;gap:10px;margin-bottom:14px;flex-wrap:wrap}
.lb-controls select{padding:8px 14px;border-radius:8px;border:1px solid var(--border);background:rgba(255,255,255,0.05);color:var(--text);font-size:14px;outline:none;font-family:inherit}
.lb-table{width:100%;border-collapse:collapse}
.lb-table th{padding:10px 14px;font-size:11px;color:var(--faint);letter-spacing:0.8px;border-bottom:1px solid var(--border);text-align:left;background:rgba(255,255,255,0.02)}
.lb-table td{padding:11px 14px;border-bottom:1px solid rgba(255,255,255,0.04);font-size:14px}
.lb-table tr.top1 td{background:rgba(251,191,36,0.06)}.lb-table tr.top2 td{background:rgba(148,163,184,0.05)}.lb-table tr.top3 td{background:rgba(180,130,100,0.05)}
.lb-table tr:hover td{background:rgba(255,255,255,0.03)}
.lb-avatar{width:24px;height:24px;border-radius:50%;display:inline-grid;place-items:center;color:#fff;font-size:11px;font-weight:700;vertical-align:middle;margin-right:6px}

/* Messages */
.msg-form{display:flex;gap:10px;margin-bottom:18px}
.msg-form input{flex:1;padding:10px 14px;border-radius:10px;border:1px solid var(--border);background:rgba(255,255,255,0.04);color:var(--text);font-size:14px;outline:none;font-family:inherit}
.msg-form input:focus{border-color:var(--indigo);box-shadow:0 0 0 3px rgba(99,102,241,0.15)}
.msg-item{display:flex;gap:12px;padding:14px 0;border-bottom:1px solid rgba(255,255,255,0.04)}
.msg-item:last-child{border-bottom:none}
.msg-avatar{width:36px;height:36px;border-radius:50%;display:grid;place-items:center;color:#fff;font-size:14px;font-weight:700;flex:none}
.msg-body{flex:1;min-width:0}
.msg-head{display:flex;align-items:center;gap:10px;margin-bottom:4px}
.msg-head b{font-size:14px}.msg-head span{font-size:11px;color:var(--faint)}
.msg-text{font-size:14px;color:var(--dim);word-break:break-word}

/* Responsive */
@media(max-width:640px){
  .h-inner{height:48px}.btn-sm{padding:5px 10px;font-size:11px}
  .nav-tab{font-size:13px;padding:10px 4px}
  .game-panel{padding:12px}.diff-btn{padding:5px 10px;font-size:12px}
}

/* Utility */
.fade-in{animation:fadeIn 0.3s ease both}
@keyframes fadeIn{from{opacity:0;transform:translateY(8px)}to{opacity:1;transform:translateY(0)}}