:root{--blue:#1d4e89;--blue-strong:#163c6a;--blue-soft:#e8f0fa;--blue-border:#b9d0ea;--ink:#1c2430;--ink-soft:#5a6a7a;--bg:#f4f6f9;--card:#fff;--line:#e3e8ef;--green:#1a7f43;--green-soft:#e5f5eb;--red:#c02f2f;--red-soft:#fdecec;--amber-soft:#fdf6e3;--amber-border:#ecd9a0;--radius:12px}@media (prefers-color-scheme:dark){:root{--blue:#6ea8e8;--blue-strong:#8dbcf0;--blue-soft:#1b2a3e;--blue-border:#2e4a6d;--ink:#e8edf3;--ink-soft:#9aa8b8;--bg:#0f141a;--card:#1a2129;--line:#2a333e;--green:#4cc47e;--green-soft:#14301f;--red:#f08c8c;--red-soft:#3a1a1a;--amber-soft:#2e2712;--amber-border:#5d4f22}}*{box-sizing:border-box}html,body{background:var(--bg);color:var(--ink);-webkit-text-size-adjust:100%;margin:0;padding:0;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,sans-serif;font-size:16px;line-height:1.5}.container{max-width:760px;padding:0 14px calc(30px + env(safe-area-inset-bottom));margin:0 auto}.app-header{background:var(--blue);color:#fff;padding:calc(14px + env(safe-area-inset-top)) 16px 14px;z-index:10;position:sticky;top:0;box-shadow:0 1px 6px #0000002e}@media (prefers-color-scheme:dark){.app-header{background:#16304d}}.app-header .inner{align-items:center;gap:12px;max-width:760px;margin:0 auto;display:flex}.app-header h1{white-space:nowrap;text-overflow:ellipsis;flex:1;margin:0;font-size:17px;font-weight:700;overflow:hidden}.app-header .back{color:#fff;padding:4px 8px 4px 0;font-size:22px;line-height:1;text-decoration:none}.unit-chip{background:#ffffff29;border-radius:8px;padding:2px 9px;font-size:13px;font-weight:700}.home-title{margin:22px 2px 4px;font-size:22px}.home-sub{color:var(--ink-soft);margin:0 2px 18px;font-size:14px}.unit-card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);color:var(--ink);align-items:center;gap:14px;margin-bottom:10px;padding:13px 15px;text-decoration:none;transition:transform 60ms;display:flex}.unit-card:active{transform:scale(.985)}.unit-num{background:var(--blue);color:#fff;border-radius:10px;flex-direction:column;justify-content:center;align-items:center;min-width:46px;height:46px;font-size:17px;font-weight:800;line-height:1.1;display:flex}.unit-num small{opacity:.85;font-size:9px;font-weight:600}.unit-info{flex:1;min-width:0}.unit-info .t{font-size:15px;font-weight:650}.unit-info .s{color:var(--ink-soft);margin-top:2px;font-size:12.5px}.progress-bar{background:var(--line);border-radius:3px;height:5px;margin-top:8px;overflow:hidden}.progress-bar>div{background:var(--green);border-radius:3px;height:100%;transition:width .3s}.tabs{gap:8px;margin:16px 0;display:flex}.tabs a{text-align:center;border:1px solid var(--blue-border);background:var(--card);color:var(--blue);border-radius:10px;flex:1;padding:9px 0;font-size:15px;font-weight:650;text-decoration:none}.tabs a.active{background:var(--blue);border-color:var(--blue);color:#fff}.lesson-section{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);margin-bottom:14px;padding:16px}.section-label{background:var(--blue);color:#fff;border-radius:7px;justify-content:center;align-items:center;width:30px;height:30px;margin-bottom:10px;font-size:15px;font-weight:800;display:inline-flex}.lesson-p{margin:10px 0}.lesson-note{background:var(--blue-soft);border:1px solid var(--blue-border);white-space:pre-line;border-radius:10px;margin:10px 0;padding:12px 14px;font-size:15px}.examples{margin:8px 0;padding:0;list-style:none}.examples li{align-items:flex-start;gap:10px;padding:5px 0 5px 2px;font-size:15px;display:flex}.examples li:before{content:"";border:2px solid var(--blue);border-radius:2px;flex:none;width:8px;height:8px;margin-top:7px}.examples li .txt{flex:1}.compare{grid-template-columns:1fr 1fr;gap:10px;margin:12px 0;display:grid}@media (width<=560px){.compare{grid-template-columns:1fr}}.compare .col{border:1px solid var(--blue-border);border-radius:10px;overflow:hidden}.compare .col h4{background:var(--blue-soft);color:var(--blue-strong);border-bottom:1px solid var(--blue-border);margin:0;padding:8px 12px;font-size:13.5px}.compare .col .examples{padding:6px 12px}.gram-table-wrap{margin:12px 0;overflow-x:auto}.gram-table{border-collapse:collapse;background:var(--card);font-size:14.5px}.gram-table td{border:1.5px solid var(--blue-border);text-align:center;vertical-align:middle;padding:7px 12px;line-height:1.45}.gram-table td:first-child{text-align:right}.col-intro{margin:8px 12px 2px;font-size:14px}.filled{color:#2456a6;border-bottom:1.5px dotted var(--blue-border);white-space:pre-wrap;padding:0 3px;font-family:Bradley Hand,Segoe Print,Comic Sans MS,cursive;font-size:15.5px}@media (prefers-color-scheme:dark){.filled{color:#8fb8ee}}.example-q{background:0 0}.example-chip{background:var(--amber-soft);border:1px solid var(--amber-border);color:var(--ink-soft);letter-spacing:.3px;border-radius:20px;margin-top:6px;padding:1px 10px;font-size:11.5px;font-weight:650;display:inline-block}.speak-btn{border:1px solid var(--blue-border);background:var(--blue-soft);color:var(--blue);cursor:pointer;-webkit-tap-highlight-color:transparent;border-radius:8px;flex:none;justify-content:center;align-items:center;width:32px;height:32px;font-size:15px;display:inline-flex}.speak-btn:active{background:var(--blue-border)}.speak-btn.small{width:28px;height:28px;font-size:13px}.exercise-card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);margin-bottom:16px;padding:16px}.exercise-card h3{color:var(--blue);margin:0 0 4px;font-size:16px}.exercise-card .instructions{color:var(--ink-soft);margin:0 0 8px;font-size:14px}.exercise-card .model{background:var(--amber-soft);border:1px solid var(--amber-border);border-radius:8px;margin-bottom:10px;padding:8px 12px;font-size:13.5px}.question{border-top:1px solid var(--line);padding:12px 0}.question .q-head{align-items:flex-start;gap:8px;display:flex}.question .q-num{color:var(--blue);flex:none;min-width:22px;padding-top:3px;font-weight:700}.question .q-body{flex:1;min-width:0}.q-line{margin:2px 0}.q-prompt{white-space:pre-line;margin-bottom:8px;font-size:15px}.q-prompt .paren{color:var(--ink-soft)}.gap-input,.write-input{font:inherit;color:var(--ink);background:var(--bg);border:1.5px solid var(--line);border-bottom:2px solid var(--blue);border-radius:7px;outline:none;margin:2px;padding:4px 8px;font-size:15px}.gap-input:focus,.write-input:focus{border-color:var(--blue)}.write-row{align-items:center;gap:8px;display:flex}.write-row .starter{color:var(--blue);white-space:nowrap;font-weight:650}.write-input{flex:1;width:100%}.checked-ok{border-color:var(--green)!important;background:var(--green-soft)!important}.checked-bad{border-color:var(--red)!important;background:var(--red-soft)!important}.answer-reveal{background:var(--green-soft);color:var(--green);border-radius:8px;margin-top:7px;padding:7px 11px;font-size:14px;font-weight:550}.answer-note{color:var(--ink-soft);margin-top:6px;font-size:12.5px}.example-reveal{background:var(--blue-soft);border-radius:8px;margin-top:7px;padding:7px 11px;font-size:14px}.link-btn{color:var(--blue);cursor:pointer;background:0 0;border:none;padding:4px 0;font-size:13.5px;text-decoration:underline}.exercise-footer{align-items:center;gap:10px;margin-top:14px;display:flex}.btn{font:inherit;cursor:pointer;-webkit-tap-highlight-color:transparent;border:none;border-radius:10px;padding:10px 18px;font-weight:700}.btn-primary{background:var(--blue);color:#fff}.btn-primary:active{background:var(--blue-strong)}.btn-ghost{border:1px solid var(--line);color:var(--ink-soft);background:0 0}.score-pill{margin-left:auto;font-size:15px;font-weight:800}.score-pill.good{color:var(--green)}.score-pill.meh{color:var(--red)}.empty-note{text-align:center;color:var(--ink-soft);margin:40px 0;font-size:14px}