/* ===== 主题变量：浅色（默认） ===== */
:root{
  color-scheme: light;
  --ink:#20251f; --muted:#81877f; --line:#e3e7df; --paper:#f5f6f3; --card:#fff;
  --green:#315f49; --pale:#e8f0e9; --gold:#c99848; --red:#b74b47;
  --board-border:#4a554b; --cell-border:#dfe3dc; --cell-strong:#778177;
  --given:#343a34; --sel-bg:#dbe9dd; --rel-bg:#f1f5f0; --same-bg:#e8f0e9;
  --conflict-bg:#fcebea; --notes:#788178;
  --ctrl-ink:#50584f; --hover-border:#9db19e; --hover-bg:#f6faf6;
  --num-ink:#364139; --track:#e4e8e1; --level-ink:#727970; --locked:#c5c9c2;
  --foot:#9a9f98; --ghost-bg:#eef1ec; --ghost-ink:#50584f; --switch-track:#dde2db;
}
/* 跟随系统深色 */
@media (prefers-color-scheme: dark){
  :root:not(.light){
    color-scheme: dark;
    --ink:#e8ece6; --muted:#9aa39a; --line:#3a423b; --paper:#1c211d; --card:#262c27;
    --green:#8fceb0; --pale:#2b362f; --gold:#d8ab62; --red:#e0908a;
    --board-border:#5a6a5c; --cell-border:#3a423b; --cell-strong:#5a6a5c;
    --given:#c6cec6; --sel-bg:#33453a; --rel-bg:#2a322c; --same-bg:#2e3a32;
    --conflict-bg:#452a28; --notes:#8a948a;
    --ctrl-ink:#b8c0b8; --hover-border:#5a6a5c; --hover-bg:#2a322c;
    --num-ink:#d0d8d0; --track:#333b34; --level-ink:#8a948a; --locked:#4a544c;
    --foot:#6a746c; --ghost-bg:#333b34; --ghost-ink:#c0c8c0; --switch-track:#444d45;
  }
}
/* 手动深色（覆盖一切） */
html.dark{
  color-scheme: dark;
  --ink:#e8ece6; --muted:#9aa39a; --line:#3a423b; --paper:#1c211d; --card:#262c27;
  --green:#8fceb0; --pale:#2b362f; --gold:#d8ab62; --red:#e0908a;
  --board-border:#5a6a5c; --cell-border:#3a423b; --cell-strong:#5a6a5c;
  --given:#c6cec6; --sel-bg:#33453a; --rel-bg:#2a322c; --same-bg:#2e3a32;
  --conflict-bg:#452a28; --notes:#8a948a;
  --ctrl-ink:#b8c0b8; --hover-border:#5a6a5c; --hover-bg:#2a322c;
  --num-ink:#d0d8d0; --track:#333b34; --level-ink:#8a948a; --locked:#4a544c;
  --foot:#6a746c; --ghost-bg:#333b34; --ghost-ink:#c0c8c0; --switch-track:#444d45;
}

/* ===== 基础 ===== */
*{box-sizing:border-box}
body{margin:0;background:var(--paper);color:var(--ink);font-family:Inter,"PingFang SC","Microsoft YaHei",sans-serif;min-height:100vh}
.shell{max-width:1050px;margin:auto;padding:28px 32px 40px}
.top{display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--line);padding-bottom:20px}
.brand{display:flex;gap:12px;align-items:center}
.mark{width:38px;height:38px;border-radius:12px;background:var(--green);display:grid;place-items:center;color:var(--card);font-size:19px}
.brand h1{font-size:16px;margin:0;font-weight:650;letter-spacing:.02em}
.brand small{display:block;color:var(--muted);font-size:11px;margin-top:3px;letter-spacing:.08em}
.top-right{display:flex;align-items:center;gap:10px}
.top-note{font-size:12px;color:var(--muted)}
.theme-btn{width:34px;height:34px;border:1px solid var(--line);background:var(--card);border-radius:50%;cursor:pointer;font-size:15px;display:grid;place-items:center;color:var(--ink);transition:.15s;padding:0}
.theme-btn:hover{border-color:var(--hover-border)}

main{display:grid;grid-template-columns:minmax(330px,540px) 1fr;gap:56px;align-items:start;padding:44px 30px}
.board-wrap{max-width:520px;width:100%;margin:auto}
.eyebrow{font-size:11px;letter-spacing:.18em;text-transform:uppercase;color:var(--muted)}
.heading{display:flex;justify-content:space-between;align-items:end;margin-bottom:18px}
.heading h2{font-size:25px;margin:8px 0 0;font-weight:600}
.level-label{font-size:12px;color:var(--green);background:var(--pale);padding:7px 11px;border-radius:20px}

/* ===== 棋盘 ===== */
.board{display:grid;grid-template-columns:repeat(9,minmax(0,1fr));grid-template-rows:repeat(9,minmax(0,1fr));border:2px solid var(--board-border);border-radius:5px;overflow:hidden;background:var(--card);aspect-ratio:1;width:100%;max-width:520px;margin-inline:auto;touch-action:manipulation}
.cell{border:0;border-right:1px solid var(--cell-border);border-bottom:1px solid var(--cell-border);border-radius:0;background:var(--card);min-width:0;position:relative;display:grid;place-items:center;font:500 clamp(16px,3.3vw,25px)/1 inherit;color:var(--green);cursor:pointer;padding:0}
.cell:nth-child(3n){border-right:2px solid var(--cell-strong)}
.cell:nth-child(9n){border-right:0}
.cell:nth-child(n+19):nth-child(-n+27),.cell:nth-child(n+46):nth-child(-n+54){border-bottom:2px solid var(--cell-strong)}
.cell:nth-child(n+73){border-bottom:0}
.cell.given{font-weight:650;color:var(--given)}
.cell.selected{background:var(--sel-bg)!important}
.cell.related{background:var(--rel-bg)}
.cell.same{background:var(--same-bg)}
.cell.conflict{color:var(--red);background:var(--conflict-bg)}
.cell.error{color:var(--red)}
.cell .notes{position:absolute;inset:2px;display:grid;grid-template-columns:repeat(3,1fr);grid-template-rows:repeat(3,1fr);font-size:9px;color:var(--notes);line-height:1;pointer-events:none}
.cell .notes span{display:grid;place-items:center}

/* ===== 控制栏 ===== */
.controls{display:flex;gap:9px;justify-content:center;margin-top:18px}
.control{border:1px solid var(--line);background:var(--card);border-radius:10px;padding:10px 13px;color:var(--ctrl-ink);cursor:pointer;font-size:12px;transition:.15s}
.control:hover{border-color:var(--hover-border);color:var(--green)}
.control.active{background:var(--pale);color:var(--green);border-color:var(--hover-border)}

/* ===== 侧边栏 ===== */
.side{padding-top:15px}
.side h3{font-size:13px;font-weight:600;margin:0 0 6px}
.side-intro{font-size:12px;color:var(--muted);margin:0 0 22px}
.stats{display:grid;grid-template-columns:1fr 1fr;border:1px solid var(--line);border-radius:12px;background:var(--card);padding:17px;margin-bottom:24px}
.stat+.stat{border-left:1px solid var(--line);padding-left:18px}
.stat span{font-size:11px;color:var(--muted)}
.stat strong{display:block;margin-top:6px;font-size:20px;font-weight:550}
.progress-head{display:flex;justify-content:space-between;font-size:11px;color:var(--muted);margin:0 0 8px}
.progress{height:4px;background:var(--track);border-radius:5px;overflow:hidden;margin-bottom:27px}
.progress i{height:100%;display:block;background:var(--green);transition:width .25s}
.level-head{display:flex;justify-content:space-between;align-items:center;margin-bottom:10px}
.level-head h3{margin:0}
.level-head button{border:0;background:none;color:var(--green);font-size:11px;cursor:pointer}
.levels{display:grid;grid-template-columns:repeat(10,1fr);gap:5px;max-height:175px;overflow:auto;padding:1px}
.level{border:1px solid transparent;background:var(--card);border-radius:6px;height:28px;color:var(--level-ink);font-size:10px;cursor:pointer;position:relative;display:grid;place-items:center}
.level .lvl-num{line-height:1;pointer-events:none}
.level .best-mini{position:absolute;bottom:1px;left:0;right:0;font-size:7px;line-height:1;color:var(--gold);text-align:center;pointer-events:none}
.level.current{background:var(--green);color:#fff}
.level.current .best-mini{color:#fff;opacity:.8}
.level.done{color:var(--green);background:var(--pale)}
.level.locked{color:var(--locked);cursor:not-allowed}

.divider{height:1px;background:var(--line);margin:24px 0}
.foot{font-size:10px;color:var(--foot);margin-top:17px}

/* ===== 数字面板 ===== */
.num-head{font-size:13px;font-weight:600;margin:20px 0 10px}
.numbers{display:grid;grid-template-columns:repeat(5,1fr);gap:8px}
.num{height:46px;background:var(--card);border:1px solid var(--line);border-radius:10px;color:var(--num-ink);font-size:18px;cursor:pointer}
.num:hover,.num:focus-visible{border-color:var(--hover-border);background:var(--hover-bg)}
.num:disabled{opacity:.32;cursor:default}
.number-hint{font-size:11px;color:var(--muted);margin:10px 0 23px}
.message{height:20px;color:var(--green);font-size:12px;text-align:center;margin-top:13px}

/* ===== 完成弹窗 ===== */
.overlay{position:fixed;inset:0;background:rgba(24,34,27,.45);display:none;place-items:center;z-index:50;padding:20px}
.overlay.show{display:grid}
.modal{background:var(--card);border-radius:16px;padding:26px 26px 22px;width:100%;max-width:340px;box-shadow:0 18px 50px rgba(0,0,0,.18);text-align:center}
.modal .trophy{font-size:34px}
.modal h3{margin:10px 0 4px;font-size:20px;font-weight:650}
.modal .sub{color:var(--muted);font-size:12px;margin:0 0 16px}
.modal-stats{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-bottom:18px}
.modal-stats div{background:var(--pale);border-radius:10px;padding:12px}
.modal-stats span{font-size:11px;color:var(--muted)}
.modal-stats strong{display:block;margin-top:4px;font-size:18px;font-weight:600}
.modal-actions{display:flex;gap:10px;justify-content:center}
.modal-btn{border:0;border-radius:10px;padding:11px 18px;font-size:13px;cursor:pointer;font-weight:550}
.modal-btn.primary{background:var(--green);color:var(--card)}
.modal-btn.ghost{background:var(--ghost-bg);color:var(--ghost-ink)}
.modal-btn.record{background:var(--gold);color:var(--card)}

/* ===== 挑战模式开关 ===== */
.opt-row{display:flex;align-items:center;justify-content:space-between;margin-bottom:18px}
.opt-row label{font-size:12px;color:var(--muted)}
.switch{position:relative;width:40px;height:22px;flex:none}
.switch input{position:absolute;opacity:0;inset:0;margin:0;cursor:pointer}
.switch i{position:absolute;inset:0;background:var(--switch-track);border-radius:20px;transition:.18s;pointer-events:none}
.switch i::after{content:"";position:absolute;left:3px;top:3px;width:16px;height:16px;background:var(--card);border-radius:50%;transition:.18s}
.switch input:checked+i{background:var(--green)}
.switch input:checked+i::after{left:21px}

/* ===== 最佳成绩 ===== */
.best{font-size:11px;color:var(--gold);margin-top:5px;min-height:14px}

/* ===== 移动端 ===== */
@media(max-width:760px){
  html,body{width:100%;max-width:100%;overflow-x:hidden}
  .shell{width:100%;max-width:100%;padding:18px 14px 30px}
  .top{flex-wrap:wrap;gap:8px}
  .top-note{display:none}
  main{display:flex;flex-direction:column;gap:30px;padding:24px 0;width:100%;min-width:0}
  .board-wrap,.side{width:100%;max-width:100%;min-width:0}
  .board{width:100%;min-width:0}
  .cell{font-size:clamp(15px,6vw,26px);min-height:0;min-width:0}
  .cell .notes{font-size:8px}
  .num{min-height:46px;font-size:19px;padding:0}
  .control{padding:11px 12px;min-height:44px}
  .controls{flex-wrap:wrap}
  .numbers{grid-template-columns:repeat(5,minmax(0,1fr))}
  .levels{grid-template-columns:repeat(8,minmax(0,1fr))}
  .ach-wall{grid-template-columns:repeat(5,1fr)}
  .heading h2{font-size:21px}
  .modal{max-width:320px}
}
/* 触控反馈 */
@media(pointer:coarse){
  .cell:active{background:var(--rel-bg)}
  .num:active{background:var(--pale)}
}

/* ===== 账号：登录入口 / 用户菜单（阶段二） ===== */
.user-area{position:relative;display:inline-flex;align-items:center}
.login-btn{border:1px solid var(--line);background:var(--card);color:var(--green);border-radius:20px;padding:8px 14px;font-size:12px;cursor:pointer;font-weight:550;transition:.15s;white-space:nowrap}
.login-btn:hover{border-color:var(--hover-border);background:var(--pale)}
.user-chip{display:inline-flex;align-items:center;gap:7px;border:1px solid var(--line);background:var(--card);border-radius:20px;padding:4px 11px 4px 4px;font-size:12px;color:var(--ink);cursor:pointer;transition:.15s}
.user-chip:hover{border-color:var(--hover-border)}
.avatar{width:24px;height:24px;border-radius:50%;background:var(--green);color:var(--card);display:grid;place-items:center;font-size:12px;font-weight:650;flex:none}
.uname{max-width:90px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;font-weight:550}
.ucaret{color:var(--muted);font-size:10px}
.user-menu{position:absolute;top:calc(100% + 8px);right:0;background:var(--card);border:1px solid var(--line);border-radius:12px;box-shadow:0 10px 30px rgba(0,0,0,.12);min-width:190px;padding:8px;z-index:60}
.um-head{display:flex;flex-direction:column;gap:2px;padding:6px 8px 8px;border-bottom:1px solid var(--line);margin-bottom:6px}
.um-head strong{font-size:13px;font-weight:650}
.um-head span{font-size:11px;color:var(--muted)}
.um-exp{display:flex;justify-content:space-between;align-items:center;font-size:11px;color:var(--muted);padding:4px 8px}
.um-exp b{color:var(--green);font-size:13px}
.um-btn{width:100%;border:0;background:none;color:var(--red);font-size:12px;text-align:left;padding:9px 8px;border-radius:8px;cursor:pointer;margin-top:2px}
.um-btn:hover{background:var(--conflict-bg)}

/* ===== 登录/注册弹窗 ===== */
.auth-modal{position:relative;max-width:330px;padding:26px 24px 22px}
.auth-close{position:absolute;top:12px;right:14px;border:0;background:none;color:var(--muted);font-size:15px;cursor:pointer;padding:4px;line-height:1}
.auth-close:hover{color:var(--ink)}
.auth-tabs{display:flex;gap:6px;background:var(--ghost-bg);border-radius:11px;padding:4px;margin-bottom:18px}
.auth-tab{flex:1;border:0;background:none;padding:9px;border-radius:8px;font-size:13px;color:var(--muted);cursor:pointer;font-weight:550;transition:.15s}
.auth-tab.active{background:var(--card);color:var(--green);box-shadow:0 1px 4px rgba(0,0,0,.08)}
.auth-input{width:100%;border:1px solid var(--line);background:var(--card);color:var(--ink);border-radius:10px;padding:11px 13px;font-size:14px;margin-bottom:11px;transition:.15s}
.auth-input:focus{outline:none;border-color:var(--green);box-shadow:0 0 0 3px var(--pale)}
.auth-input::placeholder{color:var(--muted)}
.auth-submit{width:100%;border:0;background:var(--green);color:var(--card);border-radius:10px;padding:12px;font-size:14px;font-weight:600;cursor:pointer;margin-top:2px;transition:.15s}
.auth-submit:hover{filter:brightness(1.06)}
.auth-submit:disabled{opacity:.6;cursor:default}
.auth-msg{min-height:18px;margin:10px 0 0;font-size:12px;color:var(--red);text-align:center;white-space:pre-wrap}

/* ===== 等级卡（阶段三） ===== */
.level-card{border:1px solid var(--line);background:var(--card);border-radius:12px;padding:14px 16px;margin-bottom:16px}
.lc-top{display:flex;align-items:center;gap:10px;margin-bottom:10px}
.lc-badge{background:var(--green);color:var(--card);border-radius:9px;padding:4px 10px;font-size:12px;font-weight:650}
.lc-badge b{font-size:15px}
.lc-title{font-size:13px;font-weight:600;color:var(--ink)}
.lc-bar{height:6px;background:var(--track);border-radius:6px;overflow:hidden}
.lc-bar i{display:block;height:100%;background:linear-gradient(90deg,var(--green),var(--gold));border-radius:6px;transition:width .3s}
.lc-meta{margin-top:6px;font-size:11px;color:var(--muted);text-align:right}

/* ===== 勋章墙（阶段四） ===== */
.ach-head{display:flex;justify-content:space-between;align-items:center;margin:0 0 10px}
.ach-head h3{font-size:13px;font-weight:600;margin:0}
.ach-head span{font-size:11px;color:var(--muted)}
.ach-wall{display:grid;grid-template-columns:repeat(6,1fr);gap:6px;margin-bottom:24px}
.ach{border:1px solid var(--line);background:var(--card);border-radius:9px;aspect-ratio:1;display:grid;place-items:center;cursor:default;transition:.15s}
.ach-icon{font-size:19px;filter:grayscale(1);opacity:.32}
.ach.unlocked{border-color:var(--gold)}
.ach.unlocked .ach-icon{filter:none;opacity:1}
.ach:hover{border-color:var(--hover-border)}

/* ===== toast（阶段四） ===== */
.toasts{position:fixed;right:18px;bottom:18px;display:flex;flex-direction:column;gap:8px;z-index:80;pointer-events:none}
.toast{background:var(--card);color:var(--ink);border:1px solid var(--line);border-left:3px solid var(--gold);border-radius:10px;padding:10px 14px;font-size:13px;box-shadow:0 8px 24px rgba(0,0,0,.14);opacity:0;transform:translateY(8px);transition:.25s;max-width:260px}
.toast.show{opacity:1;transform:none}

/* ===== 完成弹窗经验/勋章（阶段三/四） ===== */
.modal-gain{border-top:1px dashed var(--line);margin-top:14px;padding-top:12px}
.mg-exp{font-size:16px;font-weight:650;color:var(--gold)}
.mg-tags{display:flex;gap:6px;justify-content:center;margin-top:6px}
.mg-tags span{font-size:11px;color:var(--green);background:var(--pale);border-radius:12px;padding:3px 9px}
.mg-ach{display:flex;flex-wrap:wrap;gap:6px;justify-content:center;margin-top:10px}
.mg-ach-item{font-size:11px;color:var(--ink);background:var(--ghost-bg);border-radius:12px;padding:4px 9px}