:root{--blue:#1769e0;--blue-dark:#0e4eae;--blue-soft:#eaf3ff;--ink:#172033;--muted:#64748b;--line:#dce5f0;--surface:#f6f9fd}*{box-sizing:border-box}body{font-family:Inter,ui-sans-serif,system-ui,-apple-system,"Segoe UI",sans-serif;color:var(--ink);background:var(--surface)}.navbar-brand{color:var(--ink);font-size:1.08rem}.brand-mark{display:grid;place-items:center;width:36px;height:36px;border-radius:10px;background:var(--blue);color:#fff}.hero{background:linear-gradient(135deg,#f3f8ff 0%,#fff 65%);min-height:76vh;display:flex;align-items:center}.eyebrow,.section-label{font-size:.75rem;font-weight:800;letter-spacing:.12em;color:var(--blue)}.form-card,.result-card,.explanation-card,.processing-card{background:#fff;border:1px solid var(--line);border-radius:18px;box-shadow:0 18px 50px rgba(30,75,135,.08)}.form-card{padding:2rem}.step-badge,.tag{background:var(--blue-soft);color:var(--blue-dark);padding:.42rem .7rem;border-radius:999px;font-size:.78rem;font-weight:700}.question-input{resize:vertical;line-height:1.55;border-color:#ccd8e6;background:#fbfdff}.question-input:focus{background:#fff;border-color:#6aa7f6;box-shadow:0 0 0 .25rem rgba(23,105,224,.1)}.answer-picker{display:flex;gap:.5rem}.answer-picker .btn{width:44px;height:44px;border:1px solid #c8d6e6;font-weight:700;color:var(--ink)}.btn-check:checked+.btn{background:var(--blue);border-color:var(--blue);color:#fff}.btn-primary{background:var(--blue);border-color:var(--blue)}.btn-primary:hover{background:var(--blue-dark)}.feature-icon{width:52px;height:52px;display:grid;place-items:center;margin:0 auto 1rem;border-radius:14px;background:var(--blue-soft);color:var(--blue);font-size:1.35rem}.processing-card{max-width:600px;padding:4rem 3rem}.loader-ring{width:64px;height:64px;border:6px solid var(--blue-soft);border-top-color:var(--blue);border-radius:50%;animation:spin .8s linear infinite;margin:auto}@keyframes spin{to{transform:rotate(360deg)}}.error-icon{font-size:2rem;color:#b45309}.result-card{padding:2rem}.question-text{white-space:normal;line-height:1.75;margin-top:1rem}.alternative{display:flex;gap:.85rem;align-items:flex-start;padding:1rem;margin:.7rem 0;border:1px solid var(--line);border-radius:12px}.alternative.correct{border-color:#7bd4a3;background:#f0fff6;color:#126137}.letter,.mini-letter{flex:0 0 auto;display:grid;place-items:center;width:30px;height:30px;border-radius:50%;background:#edf2f8;font-weight:800}.alternative.correct .letter,.mini-letter.is-correct{background:#18864b;color:#fff}.explanation-card{overflow:hidden}.answer-header{display:flex;align-items:center;justify-content:space-between;background:var(--blue);color:#fff;padding:1rem 1.5rem}.answer-header strong{font-size:1.5rem}.distractor{display:flex;gap:.75rem;margin-top:1rem;align-items:flex-start}.distractor p{font-size:.9rem;color:var(--muted);margin:.25rem 0}.mini-letter{width:28px;height:28px;font-size:.75rem}@media(max-width:767px){.form-card{padding:1.25rem}.hero{align-items:flex-start}.processing-card{padding:2.5rem 1.25rem}.result-card{padding:1.25rem}}