:root{--fc-navy:#081626;--fc-blue:#0f5f94;--fc-cyan:#2fb7d3;--fc-orange:#f59e0b;--fc-green:#22a06b;--fc-red:#c2413b;--fc-paper:#f5f8fb;--fc-line:#d7e1ea;--fc-text:#172333;--fc-muted:#5c6b7a}
.flashcard-app{max-width:1180px;margin:0 auto;padding:2rem 1rem 4rem}.flashcard-intro{display:grid;grid-template-columns:1.4fr .8fr;gap:1.25rem;align-items:stretch;margin-bottom:1.5rem}.flashcard-panel{background:#fff;border:1px solid var(--fc-line);border-radius:18px;box-shadow:0 12px 32px rgba(8,22,38,.08);padding:1.25rem}.flashcard-panel h2,.flashcard-panel h3{margin-top:0}.deck-stat-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:.75rem}.deck-stat{background:var(--fc-paper);border-radius:14px;padding:1rem;text-align:center}.deck-stat strong{display:block;font-size:1.65rem;color:var(--fc-blue)}.deck-stat span{font-size:.85rem;color:var(--fc-muted)}.deck-builder{display:grid;grid-template-columns:1.25fr .75fr;gap:1.25rem;margin-bottom:1.25rem}.category-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:.65rem}.category-choice{display:flex;gap:.65rem;align-items:flex-start;border:1px solid var(--fc-line);border-radius:12px;padding:.75rem;background:#fff;cursor:pointer}.category-choice:has(input:checked){border-color:var(--fc-blue);background:#eef7fd}.category-choice input{margin-top:.2rem;min-width:18px;min-height:18px}.category-choice strong{display:block}.category-choice small{display:block;color:var(--fc-muted);margin-top:.15rem}.builder-actions{display:grid;gap:.65rem;align-content:start}.builder-actions button,.flashcard-actions button,.session-actions button{border:0;border-radius:11px;padding:.78rem 1rem;font-weight:750;cursor:pointer;min-height:46px}.button-primary{background:var(--fc-blue);color:#fff}.button-random{background:var(--fc-orange);color:#18202b}.button-secondary{background:#e7eef5;color:var(--fc-text)}.button-quiet{background:#fff;border:1px solid var(--fc-line)!important;color:var(--fc-text)}.builder-actions label{font-weight:700}.builder-actions select,.builder-actions input[type=search]{width:100%;min-height:46px;border:1px solid var(--fc-line);border-radius:10px;padding:.65rem .75rem;font:inherit}.selection-summary{margin:.8rem 0 0;color:var(--fc-muted)}.study-shell{display:none}.study-shell.active{display:block}.study-toolbar{display:flex;gap:.75rem;justify-content:space-between;align-items:center;flex-wrap:wrap;margin-bottom:.8rem}.study-toolbar p{margin:0}.progress-track{height:10px;background:#dfe8ef;border-radius:999px;overflow:hidden}.progress-fill{height:100%;width:0;background:linear-gradient(90deg,var(--fc-blue),var(--fc-cyan));transition:width .25s ease}.flashcard-stage{perspective:1200px;margin:1.25rem auto;max-width:820px}.flashcard{position:relative;min-height:390px;width:100%;border:0;background:transparent;padding:0;cursor:pointer;text-align:left}.flashcard-inner{position:relative;width:100%;min-height:390px;transition:transform .55s;transform-style:preserve-3d}.flashcard.is-flipped .flashcard-inner{transform:rotateY(180deg)}.flashcard-face{position:absolute;inset:0;backface-visibility:hidden;border-radius:22px;border:1px solid var(--fc-line);box-shadow:0 18px 46px rgba(8,22,38,.14);padding:clamp(1.3rem,4vw,2.3rem);display:flex;flex-direction:column;background:#fff}.flashcard-back{transform:rotateY(180deg);background:linear-gradient(145deg,#f8fbfd,#eaf5fb)}.card-meta{display:flex;justify-content:space-between;gap:.75rem;align-items:center;margin-bottom:1.2rem}.category-badge{display:inline-flex;background:#e8f5fb;color:#075578;border-radius:999px;padding:.38rem .7rem;font-weight:800;font-size:.8rem}.level-badge{color:var(--fc-muted);font-size:.8rem}.card-term{font-size:clamp(1.85rem,6vw,3rem);line-height:1.08;margin:auto 0;text-align:center;color:var(--fc-navy)}.card-definition{font-size:clamp(1.15rem,3vw,1.45rem);line-height:1.55;margin:auto 0 1rem}.card-note{background:#fff;border-left:4px solid var(--fc-cyan);padding:.9rem 1rem;border-radius:0 10px 10px 0;margin:0}.flip-cue{text-align:center;color:var(--fc-muted);font-size:.88rem;margin-top:auto}.flashcard-actions{display:flex;justify-content:center;gap:.65rem;flex-wrap:wrap}.flashcard-actions button{min-width:145px}.button-review{background:#ffe7e4;color:#8d2f29}.button-known{background:#dff5e9;color:#14633f}.button-favorite{background:#fff3ce;color:#715100}.session-actions{display:flex;justify-content:center;gap:.65rem;flex-wrap:wrap;margin-top:.8rem}.session-summary{display:none;text-align:center;padding:2rem}.session-summary.active{display:block}.session-summary h2{font-size:2rem}.summary-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:.75rem;max-width:580px;margin:1.25rem auto}.summary-tile{background:var(--fc-paper);border-radius:14px;padding:1rem}.summary-tile strong{font-size:1.7rem;display:block}.future-packs{display:grid;grid-template-columns:repeat(3,1fr);gap:.8rem}.future-pack{border:1px dashed #9fb4c6;border-radius:14px;padding:1rem;background:#f9fbfc}.source-list{display:grid;gap:.7rem}.source-list a{display:block;border:1px solid var(--fc-line);border-radius:12px;padding:.9rem;text-decoration:none}.source-list strong{display:block}.source-list small{color:var(--fc-muted)}.keyboard-help{font-size:.82rem;color:var(--fc-muted);text-align:center;margin-top:.8rem}.empty-state{padding:1.25rem;background:#fff7df;border:1px solid #f4d27d;border-radius:12px}.flashcard-app .notice{background:#eef7fd;border-left:4px solid var(--fc-blue);padding:1rem;border-radius:0 12px 12px 0}.mastery-row{display:flex;gap:.5rem;flex-wrap:wrap;margin-top:.75rem}.mastery-pill{font-size:.78rem;border-radius:999px;padding:.32rem .6rem;background:var(--fc-paper)}
@media(max-width:820px){.flashcard-intro,.deck-builder{grid-template-columns:1fr}.future-packs{grid-template-columns:1fr}.flashcard{min-height:410px}.flashcard-inner{min-height:410px}}
@media(max-width:560px){.flashcard-app{padding:1.25rem .75rem 3rem}.category-grid{grid-template-columns:1fr}.deck-stat-grid,.summary-grid{grid-template-columns:1fr 1fr}.flashcard-face{padding:1.1rem}.card-meta{align-items:flex-start;flex-direction:column}.flashcard-actions button{flex:1 1 46%;min-width:0}.study-toolbar{align-items:flex-start}.keyboard-help{display:none}}
@media(prefers-reduced-motion:reduce){.flashcard-inner{transition:none}}