:root{--bg:#f7f7f5;--surface:#fff;--text:#2a2a2a;--text-muted:#6b6b6b;--border:#e0ddd6;--accent:#5b6e8c;--accent-bg:#eef2f7;--accent-hover:#4a5d78;--success:#4a7a4a;--success-bg:#eaf3ea;--danger:#b0524a;--danger-bg:#f7eceb;--warn:#a07a3a;--warn-bg:#f6f0e4;--radius:10px;--shadow:0 1px 3px #0000000f, 0 1px 2px #0000000a;--sans:-apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", Roboto, sans-serif;--mono:ui-monospace, "Cascadia Code", Consolas, monospace;font:16px/1.6 var(--sans);color:var(--text);background:var(--bg);-webkit-font-smoothing:antialiased}*{box-sizing:border-box}body{min-height:100vh;margin:0}#root{min-height:100vh}h1,h2,h3,h4{color:var(--text);font-weight:600;line-height:1.3}h1{margin:0 0 .5rem;font-size:1.6rem}h2{margin:0 0 .5rem;font-size:1.25rem}h3{margin:0 0 .4rem;font-size:1.05rem}p{margin:0 0 .6rem}button{border:1px solid var(--border);background:var(--surface);color:var(--text);border-radius:var(--radius);cursor:pointer;padding:.5rem 1rem;font-family:inherit;font-size:.95rem;transition:background .15s,border-color .15s,transform 50ms}button:hover{background:var(--accent-bg);border-color:var(--accent)}button:active{transform:translateY(1px)}button:disabled{opacity:.5;cursor:not-allowed}button.primary{background:var(--accent);color:#fff;border-color:var(--accent)}button.primary:hover{background:var(--accent-hover)}button.ghost{background:0 0;border-color:#0000}button.ghost:hover{background:var(--accent-bg)}button.danger{color:var(--danger);border-color:var(--danger)}button.danger:hover{background:var(--danger-bg)}input,textarea,select{border:1px solid var(--border);background:var(--surface);color:var(--text);border-radius:8px;width:100%;padding:.45rem .6rem;font-family:inherit;font-size:.95rem}input:focus,textarea:focus,select:focus{outline:2px solid var(--accent);outline-offset:-1px}.card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow);padding:1.2rem}.muted{color:var(--text-muted)}.center{text-align:center}.row{flex-wrap:wrap;align-items:center;gap:.6rem;display:flex}.row.tight{gap:.4rem}.spacer{flex:1}.badge{background:var(--accent-bg);color:var(--accent);border-radius:999px;padding:.15rem .5rem;font-size:.75rem;display:inline-block}.badge.success{background:var(--success-bg);color:var(--success)}.badge.danger{background:var(--danger-bg);color:var(--danger)}.badge.warn{background:var(--warn-bg);color:var(--warn)}.topbar{z-index:10;background:var(--surface);border-bottom:1px solid var(--border);align-items:center;gap:.8rem;padding:.6rem 1rem;display:flex;position:sticky;top:0}.topbar .brand{white-space:nowrap;font-size:1.05rem;font-weight:600}.topbar nav{flex-wrap:wrap;gap:.2rem;display:flex}.topbar nav button{padding:.35rem .7rem;font-size:.9rem}.topbar nav button.active{background:var(--accent);color:#fff;border-color:var(--accent)}.nav-toggle{background:var(--surface);border:1px solid var(--border);border-radius:8px;flex-direction:column;flex-shrink:0;justify-content:center;align-items:center;gap:4px;width:40px;height:40px;padding:9px;display:none}.nav-toggle span{background:var(--text);border-radius:2px;width:100%;height:2px;display:block}@media (width<=720px){.nav-toggle{display:flex}.topbar nav{background:var(--surface);border-bottom:1px solid var(--border);box-shadow:var(--shadow);flex-direction:column;align-items:stretch;gap:.3rem;padding:.6rem 1rem;display:none;position:absolute;top:100%;left:0;right:0}.topbar nav.open{display:flex}.topbar nav button{text-align:left;width:100%;padding:.6rem .8rem}}.container{max-width:920px;margin:0 auto;padding:1.2rem}.grid{gap:.8rem;display:grid}.grid.cols-2{grid-template-columns:repeat(2,1fr)}.grid.cols-3{grid-template-columns:repeat(3,1fr)}@media (width<=640px){.grid.cols-2,.grid.cols-3{grid-template-columns:1fr}}.mode-card{text-align:left;cursor:pointer;flex-direction:column;gap:.3rem;display:flex}.mode-card:hover{background:var(--accent-bg);border-color:var(--accent)}.mode-card .icon{font-size:1.5rem}.mode-card .desc{color:var(--text-muted);font-size:.85rem}.flashcard{background:var(--surface);border:2px solid var(--border);border-radius:var(--radius);cursor:pointer;text-align:center;flex-direction:column;justify-content:center;align-items:center;min-height:220px;padding:2rem;transition:transform .2s;display:flex}.flashcard.flipped{border-color:var(--accent)}.flashcard .term{font-size:1.5rem;font-weight:600}.flashcard .hint{color:var(--text-muted);margin-top:.8rem;font-size:.85rem}.flashcard .def{max-width:560px;margin-top:.8rem;font-size:1.05rem}.flashcard .cn{color:var(--accent);margin-top:.4rem;font-size:1.2rem}.option-btn{text-align:left;align-items:flex-start;gap:.6rem;width:100%;padding:.7rem .9rem;display:flex}.option-btn .mark{color:var(--text-muted);font-weight:600}.option-btn.correct{background:var(--success-bg);border-color:var(--success)}.option-btn.wrong{background:var(--danger-bg);border-color:var(--danger)}.option-btn .mark.correct{color:var(--success)}.option-btn .mark.wrong{color:var(--danger)}.cw-layout{grid-template-columns:1fr;gap:1.2rem;display:grid}@media (width>=860px){.cw-layout{grid-template-columns:auto 1fr;align-items:start}}.cw-board{min-width:0;max-width:100%;overflow-x:auto}.cw-clues{min-width:0}.cw-cell{width:var(--cw,30px);height:var(--cw,30px);border:1px solid var(--border);background:var(--surface);text-transform:uppercase;justify-content:center;align-items:center;font-weight:500;display:flex}.cw-cell.block{background:var(--bg);border-color:var(--bg)}.cw-cell.selected{outline:2px solid var(--accent);outline-offset:-2px}.cw-grid{display:inline-block}.cw-row{display:flex}.cw-hidden-input{opacity:0;pointer-events:none;border:none;width:1px;height:1px;margin:0;padding:0;font-size:16px;position:fixed;top:0;left:0}.wordle-board{flex-direction:column;align-items:center;gap:6px;width:100%;display:flex}.wordle-cell{--wordle-size:min(48px, calc((100vw - 84px - (var(--cols,6) - 1) * 5px) / var(--cols,6)));width:var(--wordle-size);height:var(--wordle-size);border:2px solid var(--border);font-size:calc(var(--wordle-size) * .55);text-transform:uppercase;border-radius:4px;flex-shrink:0;justify-content:center;align-items:center;font-weight:700;display:flex}.wordle-cell.correct{background:var(--success);color:#fff;border-color:var(--success)}.wordle-cell.present{background:var(--warn);color:#fff;border-color:var(--warn)}.wordle-cell.absent{color:#fff;background:#555;border-color:#555}.wordle-row{justify-content:center;gap:5px;display:flex}.progress-bar{background:var(--border);border-radius:4px;height:8px;overflow:hidden}.progress-bar>div{background:var(--accent);height:100%;transition:width .3s}.tag-filter{flex-wrap:wrap;gap:.3rem;display:flex}.tag-filter button{padding:.25rem .6rem;font-size:.8rem}.tag-filter button.active{background:var(--accent);color:#fff;border-color:var(--accent)}.empty-state{text-align:center;color:var(--text-muted);padding:3rem 1rem}.empty-state .big{margin-bottom:.5rem;font-size:2.5rem}.stat{flex-direction:column;gap:.1rem;display:flex}.stat .num{color:var(--accent);font-size:1.4rem;font-weight:600}.stat .label{color:var(--text-muted);font-size:.8rem}textarea{resize:vertical;min-height:80px}.gate{justify-content:center;align-items:center;min-height:100vh;padding:1.2rem;display:flex}.gate-card{text-align:center;width:100%;max-width:420px}.gate-card label{text-align:left;color:var(--text-muted);margin-top:.8rem;font-size:.85rem;display:block}.gate-card input{margin-top:.3rem}.gate-card .big{font-size:2.5rem}.gate-card button{width:100%;margin-top:1rem}.gate-error{color:var(--danger);margin-top:.5rem;font-size:.85rem}