:root{--dse-purple:#6c4cff;--dse-blue:#3f7cff;--dse-teal:#10b9a4;--dse-coral:#ff6b6b;--dse-ink:#172033;--dse-muted:#667085;--dse-line:#e7e9f1;--dse-surface:#f7f8fc}
.dse-platform{color:var(--dse-ink);max-width:1120px;margin:0 auto}.dse-section-intro{max-width:760px;margin-bottom:32px}.dse-section-intro h2{font-size:clamp(1.8rem,4vw,2.8rem);margin:10px 0}.dse-section-intro p{color:var(--dse-muted);font-size:1.05rem}.dse-empty{padding:42px;border:1px dashed #c8ccda;border-radius:24px;background:var(--dse-surface);text-align:center}.dse-empty h2,.dse-empty h3{margin-top:0}.dse-filters{display:grid;grid-template-columns:1fr 1fr 1.5fr auto;gap:14px;align-items:end;padding:20px;border:1px solid var(--dse-line);border-radius:22px;background:#fff;margin-bottom:28px}.dse-filters label,.dse-discussion-form label{display:grid;gap:7px;font-weight:700}.dse-filters select,.dse-filters input,.dse-discussion-form textarea{width:100%;border:1px solid #d7dbe8;border-radius:12px;padding:12px 14px;background:#fff;color:var(--dse-ink);font:inherit}.dse-paper-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:20px}.dse-paper-card,.dse-mistake,.dse-discussion-list article{border:1px solid var(--dse-line);border-radius:22px;padding:24px;background:#fff;box-shadow:0 10px 34px rgba(53,62,94,.07)}.dse-paper-card{display:flex;flex-direction:column}.dse-paper-card h3{font-size:1.3rem;margin:16px 0 8px}.dse-paper-card>p{color:var(--dse-muted);flex:1}.dse-card-top,.dse-paper-meta{display:flex;flex-wrap:wrap;align-items:center;gap:8px}.dse-subject,.dse-source,.dse-status{display:inline-flex;padding:6px 10px;border-radius:999px;font-size:.78rem;font-weight:800}.dse-subject{background:#edf2ff;color:#315fc9}.dse-source-original{background:#e8fbf6;color:#087d6d}.dse-source-ai_assisted{background:#f0ebff;color:#6941c6}.dse-source-licensed{background:#fff1e8;color:#b54708}.dse-paper-meta{color:var(--dse-muted);font-size:.88rem;margin:16px 0}.dse-paper-meta span+span:before{content:'•';margin-right:8px;color:#c1c5d0}.dse-paper-card .arena-button{align-self:flex-start}.dse-quiz-header{display:flex;justify-content:space-between;gap:24px;align-items:center;padding:24px;border-radius:22px;background:linear-gradient(125deg,#f2efff,#edf8ff)}.dse-quiz-header h2{margin:8px 0}.dse-back-link{font-weight:750;text-decoration:none}.dse-timer{min-width:130px;padding:15px 20px;border-radius:16px;background:#fff;text-align:center;box-shadow:0 8px 25px rgba(53,62,94,.08)}.dse-timer span{display:block;font-size:.75rem;color:var(--dse-muted)}.dse-timer strong{display:block;font-size:1.55rem;font-variant-numeric:tabular-nums}.dse-timer.is-ended{background:#fff0f0;color:#c43a3a}.dse-quiz-progress{position:sticky;top:8px;z-index:5;margin:14px 0 24px;padding:12px 16px;border:1px solid var(--dse-line);border-radius:14px;background:rgba(255,255,255,.94);backdrop-filter:blur(10px)}.dse-quiz-progress>span{font-weight:750;font-size:.9rem}.dse-quiz-progress>div,.dse-meter{height:8px;margin-top:8px;border-radius:999px;background:#e8eaf2;overflow:hidden}.dse-quiz-progress i,.dse-meter i{display:block;width:0;height:100%;border-radius:inherit;background:linear-gradient(90deg,var(--dse-purple),var(--dse-teal));transition:width .25s ease}.dse-question{border:1px solid var(--dse-line);border-radius:20px;padding:24px;margin:0 0 18px;background:#fff}.dse-question legend{display:flex;gap:12px;padding:0 4px;font-size:1.08rem;font-weight:780}.dse-question legend>span,.dse-review h3>span{display:inline-grid;flex:none;place-items:center;width:32px;height:32px;border-radius:10px;background:#ede9ff;color:#5d3dcc}.dse-option-list{display:grid;gap:10px;margin-top:20px}.dse-option-list label{display:flex;align-items:center;gap:12px;padding:14px;border:1px solid #dee1eb;border-radius:14px;cursor:pointer;transition:.18s}.dse-option-list label:hover{border-color:#a899ff;background:#faf9ff}.dse-option-list label:has(input:checked){border-color:var(--dse-purple);background:#f3f0ff;box-shadow:0 0 0 2px rgba(108,76,255,.08)}.dse-option-list input{accent-color:var(--dse-purple)}.dse-option-label{display:grid;place-items:center;width:30px;height:30px;border-radius:50%;background:#eef0f5;font-weight:800}.dse-submit-bar{display:flex;justify-content:space-between;align-items:center;gap:20px;padding:20px 24px;border-radius:18px;background:var(--dse-ink);color:#fff}.dse-submit-bar p{margin:0}.dse-submit-bar button:disabled{opacity:.55}.dse-result-hero{text-align:center;padding:36px;border-radius:28px;background:linear-gradient(135deg,#f1ecff,#eafaff)}.dse-score-ring{display:grid;place-items:center;width:170px;height:170px;margin:24px auto;border-radius:50%;background:radial-gradient(closest-side,#fff 76%,transparent 77% 99%),conic-gradient(var(--dse-purple) calc(var(--score)*1%),#dfe2eb 0)}.dse-score-ring strong{font-size:2.4rem;line-height:1}.dse-score-ring span{font-size:.85rem;color:var(--dse-muted);margin-top:-44px}.dse-result-hero .arena-actions{justify-content:center}.dse-review-list{display:grid;gap:18px;margin-top:28px}.dse-review{border:1px solid var(--dse-line);border-left:6px solid var(--dse-teal);border-radius:18px;padding:22px;background:#fff}.dse-review.is-wrong{border-left-color:var(--dse-coral)}.dse-review h3{display:flex;gap:12px;font-size:1.05rem}.dse-review.is-wrong h3>span{background:#fff0f0;color:#c43a3a}.dse-correct-answer{color:#087d6d}.dse-explanation{padding:14px 16px;border-radius:12px;background:var(--dse-surface)}.dse-explanation p{margin:6px 0 0}.dse-mistake-list{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:18px}.dse-mistake.is-resolved{opacity:.76}.dse-status{background:#fff1f1;color:#b42318}.dse-mistake.is-resolved .dse-status{background:#e8fbf6;color:#087d6d}.dse-stat-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:15px}.dse-stat-grid>div{padding:22px;border-radius:20px;background:#fff;border:1px solid var(--dse-line)}.dse-stat-grid span{display:block;color:var(--dse-muted)}.dse-stat-grid strong{font-size:2.2rem;margin-right:5px}.dse-stat-grid small{font-weight:700}.dse-subheading{margin:34px 0 16px}.dse-subject-progress{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px}.dse-subject-progress>div{padding:18px;border:1px solid var(--dse-line);border-radius:16px;background:#fff}.dse-subject-progress>div>div:first-child{display:flex;justify-content:space-between;gap:12px}.dse-subject-progress span{color:var(--dse-muted);font-size:.9rem}.dse-history{border:1px solid var(--dse-line);border-radius:18px;overflow:hidden}.dse-history>a{display:flex;justify-content:space-between;align-items:center;gap:20px;padding:16px 20px;background:#fff;text-decoration:none;color:inherit}.dse-history>a+a{border-top:1px solid var(--dse-line)}.dse-history a:hover{background:#fafaff}.dse-history span,.dse-history small{display:block}.dse-history small{color:var(--dse-muted);margin-top:3px}.dse-history b{font-size:1.2rem;color:var(--dse-purple)}.dse-discussion-form{padding:22px;border:1px solid var(--dse-line);border-radius:20px;background:#fff;margin-bottom:24px}.dse-discussion-form textarea{min-height:120px;resize:vertical}.dse-discussion-form p{margin-bottom:0;color:var(--dse-muted)}.dse-discussion-list{display:grid;gap:14px}.dse-discussion-list article header{display:flex;align-items:center;gap:10px}.dse-discussion-list article header div,.dse-discussion-list article small{display:block}.dse-discussion-list article small{color:var(--dse-muted)}.dse-avatar{display:grid;place-items:center;width:42px;height:42px;border-radius:50%;background:linear-gradient(135deg,var(--dse-purple),var(--dse-blue));color:#fff;font-weight:800}.dse-helpful{border:0;border-radius:999px;padding:8px 13px;background:#f0f2f7;color:#50566a;cursor:pointer}.dse-helpful.is-selected{background:#e8fbf6;color:#087d6d}.dse-quick-links{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px;margin:24px 0}.dse-quick-links a{display:grid;gap:4px;padding:18px;border:1px solid var(--dse-line);border-radius:16px;text-decoration:none}.dse-quick-links a:hover{border-color:#a899ff;background:#faf9ff}.dse-quick-links span{font-size:.86rem;color:var(--dse-muted)}
@media(max-width:900px){.dse-filters{grid-template-columns:1fr 1fr}.dse-paper-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.dse-stat-grid{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media(max-width:640px){.dse-filters,.dse-paper-grid,.dse-mistake-list,.dse-subject-progress,.dse-quick-links{grid-template-columns:1fr}.dse-quiz-header,.dse-submit-bar{align-items:stretch;flex-direction:column}.dse-timer{align-self:flex-start}.dse-question{padding:18px}.dse-stat-grid{grid-template-columns:1fr 1fr}.dse-result-hero{padding:28px 16px}.dse-score-ring{width:145px;height:145px}}