*,:before,:after{box-sizing:border-box;margin:0;padding:0}:root{--bg:#f5f5f3;--surface:#fff;--border:#e0e0e0;--text:#1a1a1a;--text-secondary:#6b6b6b;--accent:#2563eb;--accent-hover:#1d4ed8;--radius:12px;--shadow:0 2px 8px #00000014;--shadow-card:0 4px 24px #0000001a;--der:#1e40af;--die:#9f1239;--das:#065f46;--again:#dc2626;--hard:#ea580c;--good:#16a34a;--easy:#2563eb}html,body{height:100%}body{background:var(--bg);color:var(--text);-webkit-font-smoothing:antialiased;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,sans-serif;line-height:1.5}button{cursor:pointer;border:none;outline:none;font-family:inherit}button:focus-visible{outline:2px solid var(--accent);outline-offset:2px}.app{flex-direction:column;max-width:600px;min-height:100dvh;margin:0 auto;padding:0 16px;display:flex}.app-header{text-align:center;padding:32px 0 16px}.app-header h1{letter-spacing:-.02em;font-size:1.75rem;font-weight:700}.app-subtitle{color:var(--text-secondary);margin-top:4px;font-size:.875rem}.app-main{flex-direction:column;flex:1;gap:20px;padding-bottom:80px;display:flex}.category-filter{flex-wrap:wrap;gap:8px;display:flex}.cat-btn{background:var(--surface);border:1px solid var(--border);color:var(--text-secondary);border-radius:999px;padding:6px 14px;font-size:.8125rem;transition:background .15s,color .15s,border-color .15s}.cat-btn:hover{background:var(--border);color:var(--text)}.cat-btn.active{background:var(--text);color:var(--surface);border-color:var(--text)}.deck-stats{flex-direction:column;gap:20px;display:flex}.stats-grid{grid-template-columns:repeat(3,1fr);gap:12px;display:grid}.stat-box{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow);flex-direction:column;align-items:center;gap:4px;padding:20px 12px;display:flex}.stat-number{font-size:2rem;font-weight:700;line-height:1}.stat-label{color:var(--text-secondary);text-transform:uppercase;letter-spacing:.05em;font-size:.75rem}.stat-due .stat-number{color:var(--again)}.stat-new .stat-number{color:var(--accent)}.stat-learned .stat-number{color:var(--good)}.btn-primary{border-radius:var(--radius);background:var(--text);width:100%;color:var(--surface);padding:14px 20px;font-size:1rem;font-weight:600;transition:background .15s,opacity .15s}.btn-primary:hover:not(:disabled){background:#333}.btn-primary:disabled{opacity:.45;cursor:default}.btn-back{background:var(--surface);border:1px solid var(--border);color:var(--text-secondary);box-shadow:var(--shadow);white-space:nowrap;border-radius:999px;padding:10px 20px;font-size:.875rem;transition:background .15s,color .15s;position:fixed;bottom:20px;left:50%;transform:translate(-50%)}.btn-back:hover{background:var(--border);color:var(--text)}.session-actions{gap:10px;display:flex;position:fixed;bottom:20px;left:50%;transform:translate(-50%)}.session-actions .btn-back{position:static;transform:none}.btn-save-session{color:var(--text);border-color:var(--accent,#6366f1)}.btn-cancel-session{opacity:.7}.direction-toggle{background:var(--surface);border:1px solid var(--border);box-shadow:var(--shadow);border-radius:999px;align-self:center;gap:2px;padding:3px;display:flex}.dir-btn{color:var(--text-secondary);letter-spacing:.02em;background:0 0;border-radius:999px;padding:6px 16px;font-size:.8125rem;font-weight:600;transition:background .15s,color .15s}.dir-btn:hover:not(.active){background:var(--border);color:var(--text)}.dir-btn.active{background:var(--text);color:var(--surface)}.flashcard-wrapper{flex-direction:column;align-items:center;gap:20px;padding-top:8px;display:flex}.session-progress{color:var(--text-secondary);font-size:.8125rem}.card-scene{perspective:1000px;cursor:pointer;width:100%;height:260px}.card-scene:hover .card-face{box-shadow:0 6px 32px #00000021}.card-scene{transform-style:preserve-3d;transition:transform .45s cubic-bezier(.4,0,.2,1);position:relative}.card-scene.is-flipped{transform:rotateY(180deg)}.card-face{border-radius:var(--radius);background:var(--surface);border:1px solid var(--border);box-shadow:var(--shadow-card);backface-visibility:hidden;-webkit-user-select:none;user-select:none;flex-direction:column;justify-content:center;align-items:center;gap:12px;padding:32px 28px;display:flex;position:absolute;inset:0}.card-back{transform:rotateY(180deg)}.article-badge{letter-spacing:.08em;text-transform:uppercase;border-radius:999px;padding:4px 12px;font-size:.8rem;font-weight:700}.article-der{color:var(--der);background:#dbeafe}.article-die{color:var(--die);background:#ffe4e6}.article-das{color:var(--das);background:#d1fae5}.card-german{letter-spacing:-.02em;text-align:center;font-size:2.25rem;font-weight:700}.card-plural{color:var(--text-secondary);font-size:.875rem}.card-hint{color:var(--border);margin-top:8px;font-size:.75rem}.card-english{text-align:center;font-size:1.75rem;font-weight:600}.card-example{color:var(--text-secondary);text-align:center;max-width:320px;font-size:.9rem;font-style:italic}.rating-row{grid-template-columns:repeat(4,1fr);gap:8px;width:100%;display:grid}.rating-placeholder{pointer-events:none;visibility:hidden;height:48px}.btn-rating{border-radius:var(--radius);color:#fff;padding:12px 8px;font-size:.875rem;font-weight:600;transition:filter .15s,transform .1s}.btn-rating:hover{filter:brightness(1.1)}.btn-rating:active{transform:scale(.97)}.btn-again{background:var(--again)}.btn-hard{background:var(--hard)}.btn-good{background:var(--good)}.btn-easy{background:var(--easy)}.session-done{text-align:center;flex-direction:column;align-items:center;gap:16px;padding-top:48px;display:flex}.session-done h2{font-size:1.5rem;font-weight:700}.session-done p{color:var(--text-secondary)}.session-done .btn-primary{max-width:240px;margin-top:8px}@media (width<=400px){.card-german{font-size:1.75rem}.card-english{font-size:1.4rem}.btn-rating{padding:10px 4px;font-size:.8rem}.stats-grid{gap:8px}.stat-number{font-size:1.6rem}}