:root{--bg: #11131f;--surface: #1b1e2e;--surface-2: #242941;--text: #f2f3f8;--text-dim: #a3a9c2;--accent: #7c6cf5;--accent-dim: #4b3fb0;--ok: #46c08a;--warn: #e8b23a;--radius: 14px;--nav-height: 64px;color-scheme:dark}*{box-sizing:border-box}html,body{margin:0;padding:0;background:var(--bg);color:var(--text);font-family:system-ui,-apple-system,Segoe UI,Roboto,sans-serif;font-size:16px;line-height:1.45;-webkit-text-size-adjust:100%}.app{max-width:640px;margin:0 auto;padding:16px 16px calc(var(--nav-height) + 24px)}.app-center{display:grid;place-items:center;min-height:70vh}h1{font-size:1.5rem;margin:0 0 4px}h2{font-size:1.05rem;margin:0 0 8px;display:flex;align-items:center;gap:8px}.screen-header{margin-bottom:16px}.hint{color:var(--text-dim);font-size:.85rem;margin:2px 0}.hint.ok{color:var(--ok)}.card{background:var(--surface);border-radius:var(--radius);padding:14px;margin-bottom:14px}.stack{display:flex;flex-direction:column;gap:14px}.row{display:flex;align-items:center;gap:8px}.row-between{display:flex;align-items:center;justify-content:space-between;gap:12px}.field{display:flex;flex-direction:column;gap:6px;border:0;margin:0;padding:0;font-size:.9rem}.field>span,.field legend{color:var(--text-dim);font-size:.8rem;text-transform:uppercase;letter-spacing:.04em;padding:0}input,select{background:var(--surface-2);border:1px solid transparent;border-radius:10px;color:var(--text);font-size:1rem;padding:12px;width:100%}input:focus-visible,select:focus-visible,button:focus-visible{outline:2px solid var(--accent);outline-offset:2px}.unit{color:var(--text-dim);font-size:.85rem;white-space:nowrap}button{font:inherit;cursor:pointer}.primary,.secondary{border:0;border-radius:12px;padding:14px;width:100%;font-weight:600}.primary{background:var(--accent);color:#fff}.primary:disabled{background:var(--accent-dim);color:#d7d4f5;cursor:not-allowed}.secondary{background:var(--surface-2);color:var(--text);margin-top:10px}.chips{display:flex;gap:8px;overflow-x:auto}.chips-wrap{flex-wrap:wrap;overflow:visible;margin-top:10px}.chip{background:var(--surface-2);border:1px solid transparent;border-radius:999px;color:var(--text);padding:8px 14px;font-size:.85rem;white-space:nowrap}.chip-active{background:var(--accent);border-color:var(--accent);color:#fff}.tiles{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin-bottom:14px}.tile{background:var(--surface);border-radius:var(--radius);padding:12px 8px;text-align:center;display:grid;gap:2px}.tile-value{font-size:1.35rem;font-weight:700}.tile-label{color:var(--text-dim);font-size:.75rem}.avatar{display:grid;place-items:center;background:var(--surface-2);border-radius:50%}.subject-icon{display:grid;place-items:center;width:28px;height:28px;border-radius:8px;background:var(--surface-2);font-size:.9rem}.node-list{list-style:none;margin:10px 0 0;padding:0;display:flex;flex-direction:column;gap:8px}.node{background:var(--surface-2);border-radius:10px;padding:10px 12px;display:flex;align-items:center;justify-content:space-between;gap:10px}.node-collapsible{display:block}.node-button{background:none;border:0;color:inherit;padding:0;text-align:left;width:100%;display:flex;align-items:center;justify-content:space-between;gap:10px}.node span.hint{display:block}.node-locked{opacity:.6}.node-title{display:block;font-weight:600}.badge{background:var(--bg);border-radius:999px;color:var(--text-dim);font-size:.75rem;padding:4px 10px;white-space:nowrap}.badge-practised{color:var(--warn)}.badge-mastered{color:var(--ok)}.navbar{position:fixed;bottom:0;left:0;right:0;height:var(--nav-height);display:grid;grid-template-columns:repeat(4,1fr);background:var(--surface);border-top:1px solid #000;padding-bottom:env(safe-area-inset-bottom)}.nav-item{background:none;border:0;color:var(--text-dim);display:grid;gap:2px;place-items:center}.nav-item-active{color:var(--text)}.nav-glyph{font-size:1.15rem}.nav-label{font-size:.7rem}