:root{
  --bg:#f6f7fb; --fg:#0f172a; --muted:#667085;
  --card:#ffffff; --shadow:0 18px 50px rgba(31,41,55,.10);
  --primary:#6f7bf7; --ok:#10b981; --bad:#ef4444;
}
body.dark{
  --bg:#0f1220; --fg:#e9ecf5; --muted:#9aa3b2;
  --card:#141a2e; --shadow:0 20px 60px rgba(0,0,0,.35);
  --primary:#8aa2ff;
}
*{box-sizing:border-box}
html,body{height:100%}
body{margin:0;background:var(--bg);color:var(--fg);font-family:ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial}

/* 顶部工具条：logo与Start同一水平线 */
.toolbar{position:sticky;top:16px;display:flex;justify-content:center;z-index:20;padding-top:10px}
.pill{display:flex;align-items:center;gap:14px;padding:12px 16px;background:var(--card);border-radius:16px;box-shadow:var(--shadow);min-width:880px;max-width:1100px;width:90%}
.brand-text{font-weight:900;letter-spacing:.4px;font-size:22px;color:var(--primary)}
.sep-dot{color:var(--muted)}
.select-wrap{display:flex;align-items:center;gap:10px}
.chip{background:rgba(127,140,255,.18);color:var(--primary);padding:6px 10px;border-radius:10px;font-weight:700}
select{appearance:none;border:1px solid rgba(127,140,255,.3);background:var(--card);color:var(--fg);padding:6px 10px;border-radius:10px;font-weight:600}
.icon{border:none;background:transparent;cursor:pointer;padding:6px 8px;border-radius:10px;color:var(--primary)}
.icon:hover{background:rgba(127,140,255,.12)}
.ico{width:22px;height:22px;display:block}
.spacer{flex:1}
.btn-primary{background:var(--primary);color:#fff;border:none;padding:10px 18px;border-radius:12px;font-weight:800;cursor:pointer;box-shadow:0 8px 20px rgba(91,110,246,.35)}
.btn-primary:hover{filter:brightness(1.06)}
.btn-ghost{background:transparent;border:1px solid rgba(127,140,255,.4);color:var(--primary);padding:9px 14px;border-radius:12px;font-weight:700;cursor:pointer}
.btn-ghost:hover{background:rgba(127,140,255,.1)}
.toggle-meaning{border:1px solid rgba(127,140,255,.4);background:transparent;color:var(--primary);padding:6px 10px;border-radius:10px;font-weight:800}

/* 小眼睛菜单 */
.menu-wrap{position:relative}
.menu{position:absolute;top:42px;left:0;background:var(--card);border-radius:12px;box-shadow:var(--shadow);padding:10px 12px;display:flex;flex-direction:column;gap:8px;z-index:25}
.menu.hide{display:none}
.menu label{font-size:14px;display:flex;gap:8px;align-items:center;color:var(--fg)}

/* 舞台 */
.stage{min-height:56vh;display:flex;align-items:center;justify-content:center;padding:60px 16px 20px;background:radial-gradient(1000px 380px at 60% -40px,rgba(127,140,255,.18),transparent 60%)}
.center{text-align:center;max-width:980px;width:100%}
.hint-top{font-size:20px;opacity:.8;margin-bottom:8px}
.sides{position:relative;height:24px}
.side{position:absolute;top:-8px;font-size:20px;font-weight:800;color:rgba(15,23,42,.35)}
.side-left{left:0}.side-right{right:0}

/* 单词与释义 */
.meta{height:24px;margin-bottom:6px}
.pos{font-weight:700;color:var(--primary)}
.root-info{font-size:14px;color:var(--muted);margin-left:6px}
.meaning{opacity:.9;margin-bottom:12px}

/* 完整字母行：逐位判定 */
.letters{display:inline-flex;gap:10px;padding:18px 22px;border-radius:16px;background:var(--card);box-shadow:var(--shadow);outline:none;user-select:none}
.letter{font-size:32px;font-weight:800;letter-spacing:2px;padding:0 2px;border-bottom:3px solid rgba(127,140,255,.3)}
.letter.ok{color:var(--ok);border-color:rgba(16,185,129,.5)}
.letter.bad{color:var(--bad);border-color:rgba(239,68,68,.5)}
.hidden-char{color:transparent;text-shadow:0 0 14px rgba(0,0,0,0.05)} /* 隐藏但保留占位 */
.subhint{margin-top:10px;font-size:14px;color:var(--muted)}

/* 统计卡 */
.stats{display:flex;justify-content:center;padding:28px 16px 60px}
.card{background:var(--card);border-radius:18px;box-shadow:var(--shadow);display:flex;align-items:stretch;padding:24px 10px;gap:10px;min-width:880px;max-width:1100px;width:90%}
.stat-item{flex:1;text-align:center}
.stat-value{font-size:28px;font-weight:900}
.stat-label{font-size:13px;opacity:.65;margin-top:6px}
.divider{width:1px;background:linear-gradient(180deg,transparent,rgba(148,163,184,.45),transparent)}

@media (max-width:900px){
  .pill,.card{min-width:auto;width:100%}
  .pill{flex-wrap:wrap;row-gap:8px}
}