:root{--bg: #ffffff;--fg: #16181d;--muted: #6b7280;--line: #e4e6eb;--accent: #2f5fd0;--correct: #1d7a4c;--wrong: #b3261e;--card: #f7f8fa}@media(prefers-color-scheme:dark){:root{--bg: #14161a;--fg: #e8eaee;--muted: #9aa1ad;--line: #2b2f36;--accent: #7ba1f5;--correct: #5fd39a;--wrong: #f08a80;--card: #1c1f25}}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--fg);font-family:Pretendard,Segoe UI,system-ui,sans-serif;line-height:1.6}.app{max-width:780px;margin:0 auto;padding:24px 16px 64px}.app-header{border-bottom:1px solid var(--line);margin-bottom:24px}.app-header h1{font-size:20px;margin:0 0 12px}.app-header nav{display:flex;gap:8px}.app-header nav a{padding:8px 14px;border-radius:8px 8px 0 0;text-decoration:none;color:var(--muted);font-size:14px}.app-header nav a.active{color:var(--fg);background:var(--card);font-weight:600}.count{display:inline-block;margin-left:6px;padding:0 6px;border-radius:999px;background:var(--line);font-size:12px}.meta{font-size:13px;color:var(--muted);margin-bottom:4px}h2{font-size:18px;margin:0 0 8px}.prompt{white-space:pre-line;margin:0 0 16px}.visual{max-width:100%;display:block;margin:0 0 16px;border:1px solid var(--line);border-radius:8px}.choices{list-style:none;padding:0;margin:0;display:grid;gap:8px}.choices button{width:100%;text-align:left;padding:12px 14px;border:1px solid var(--line);border-radius:10px;background:var(--card);color:var(--fg);font:inherit;cursor:pointer}.choices button:hover:enabled{border-color:var(--accent)}.choices button.correct{border-color:var(--correct);color:var(--correct)}.choices button.wrong{border-color:var(--wrong);color:var(--wrong)}.choice-id{display:inline-block;width:22px;font-weight:700;color:var(--muted)}.explanation{margin-top:20px;padding:16px;background:var(--card);border-radius:10px}.explanation .short{font-weight:600;margin:0 0 8px}.explanation .detailed{white-space:pre-line;margin:0}.explanation .distractor{margin:12px 0 0;color:var(--wrong)}.next{margin-top:16px;padding:10px 16px;border:0;border-radius:8px;background:var(--accent);color:#fff;font:inherit;cursor:pointer}.empty{padding:32px;background:var(--card);border-radius:10px;color:var(--muted)}.empty strong{color:var(--fg)}.draft-banner{font-size:13px;background:var(--card);border:1px dashed var(--line);border-radius:8px;padding:10px 12px;color:var(--muted)}.objective{font-size:17px;font-weight:600;margin:0 0 4px}.exam-relevance{font-size:14px;color:var(--muted);margin:0 0 20px}.prediction{border:1px solid var(--accent);border-radius:12px;padding:16px;margin-bottom:16px}.prediction h3{margin:0 0 8px;font-size:15px;color:var(--accent)}.prediction p{margin:0 0 12px}.choices button.picked{border-color:var(--accent);font-weight:600}.locked{color:var(--muted);font-size:14px;padding:16px;text-align:center}.stage-nav{display:flex;gap:6px;flex-wrap:wrap;margin-bottom:12px}.stage-nav button{padding:6px 12px;border:1px solid var(--line);border-radius:999px;background:transparent;color:var(--muted);font:inherit;font-size:13px;cursor:pointer}.stage-nav button.active{background:var(--accent);border-color:var(--accent);color:#fff}.stage-panel{background:var(--card);border-radius:12px;padding:16px}.stage-panel h3{margin:0 0 12px;font-size:16px}.field{margin-bottom:12px}.field-label{display:block;font-size:12px;color:var(--muted);text-transform:uppercase;letter-spacing:.04em;margin-bottom:2px}.field ul{margin:0;padding-left:20px}.field p{margin:0}.final-hold{font-size:12px;color:var(--correct);margin:0}.module-exit{margin-top:16px;padding-top:16px;border-top:1px solid var(--line)}.warn-inline{color:var(--wrong);font-size:13px}.review-hint{font-size:13px;color:var(--muted);margin-bottom:16px}.review-card{border:1px solid var(--line);border-radius:12px;padding:16px;margin-bottom:16px}.review-choices{margin:0 0 12px;padding-left:20px;display:grid;gap:10px}.review-choices li.correct{color:var(--correct)}.tag{margin-left:8px;padding:1px 6px;border-radius:4px;background:var(--correct);color:var(--bg);font-size:11px}.rationale{font-size:13px;color:var(--muted);margin-top:4px;padding-left:22px}.decision{margin-left:8px;padding:1px 8px;border-radius:999px;border:1px solid var(--line);font-size:11px}.decision.accept{color:var(--correct);border-color:var(--correct)}.decision.revise{color:var(--accent);border-color:var(--accent)}.decision.discard{color:var(--wrong);border-color:var(--wrong)}.review-note{font-size:13px;background:var(--card);border-left:3px solid var(--accent);padding:8px 12px;margin:8px 0;white-space:pre-line}.error-type{font-family:ui-monospace,monospace;font-size:12px;color:var(--accent)}code{font-family:ui-monospace,monospace;font-size:12px}.mol-viewer{border:1px solid var(--line);border-radius:12px;margin:16px 0;overflow:hidden}.mol-toolbar{display:flex;flex-wrap:wrap;align-items:center;gap:10px;padding:8px 12px;background:var(--card);border-bottom:1px solid var(--line);font-size:13px}.mol-toolbar label{display:inline-flex;align-items:center;gap:4px;color:var(--muted);cursor:pointer}.mol-toolbar input{accent-color:var(--accent)}.mol-spacer{flex:1 1 auto}.mol-pg{padding:1px 8px;border-radius:999px;background:var(--accent);color:var(--bg);font-weight:600}.mol-viewer{user-select:none;-webkit-user-select:none}.mol-canvas{display:block;width:100%;touch-action:none;cursor:grab;background:var(--bg)}.mol-canvas:active{cursor:grabbing}.mol-canvas text{user-select:none;-webkit-user-select:none}.mol-atom-label{pointer-events:none}.mol-bond{stroke-linecap:round}.mol-atom{stroke:var(--line);stroke-width:1.5}.mol-atom-label{text-anchor:middle;font-weight:700;fill:#16181d;pointer-events:none;paint-order:stroke;stroke:#fff;stroke-width:2.5px}.mol-plane polygon{fill:var(--accent);fill-opacity:.14;stroke:var(--accent);stroke-width:1.5;stroke-dasharray:5 4}.mol-plane text{fill:var(--accent);font-size:15px;font-weight:700;text-anchor:middle}.mol-axis{cursor:pointer}.mol-axis line{stroke:var(--wrong);stroke-width:2;stroke-dasharray:7 5}.mol-axis.principal line{stroke-width:3.5;stroke-dasharray:none}.mol-axis.improper line{stroke:#8b5cf6;stroke-dasharray:3 4}.mol-axis text{fill:var(--wrong);font-size:15px;font-weight:700;text-anchor:middle}.mol-axis.improper text{fill:#8b5cf6}.mol-inversion{cursor:pointer}.mol-inversion circle{fill:var(--correct)}.mol-inversion text{fill:var(--correct);font-size:15px;font-weight:700}.mol-ops{display:flex;flex-wrap:wrap;align-items:center;gap:6px;padding:10px 12px;border-top:1px solid var(--line);background:var(--card)}.mol-ops-title{font-size:12px;color:var(--muted);margin-right:4px}.mol-ops button{padding:4px 10px;border:1px solid var(--line);border-radius:999px;background:var(--bg);color:var(--fg);font-size:13px;cursor:pointer}.mol-ops button:hover{border-color:var(--accent);color:var(--accent)}.mol-ops .mol-reset{border-style:dashed;color:var(--muted)}.mol-settled{margin:0;padding:10px 12px;font-size:13px;background:color-mix(in srgb,var(--correct) 12%,transparent);border-top:1px solid var(--line)}.mol-note,.mol-caption{margin:0;padding:8px 12px;font-size:12.5px;color:var(--muted);border-top:1px solid var(--line)}.mol-locked-hint{font-size:12px;color:var(--muted)}.landing{position:relative;min-height:100vh;display:grid;place-items:center;padding:48px 20px;overflow:hidden;background:var(--bg)}.landing-glow{position:absolute;inset:-30% -10% auto -10%;height:70vh;background:radial-gradient(40% 60% at 25% 40%,color-mix(in srgb,var(--accent) 26%,transparent),transparent 70%),radial-gradient(35% 55% at 75% 30%,color-mix(in srgb,var(--correct) 20%,transparent),transparent 70%);filter:blur(20px);pointer-events:none}.landing-inner{position:relative;max-width:660px;text-align:center}.landing-eyebrow{display:inline-block;padding:4px 12px;border:1px solid var(--line);border-radius:999px;font-size:12.5px;letter-spacing:.04em;color:var(--muted)}.landing-title{margin:18px 0 0;font-size:clamp(34px,7vw,56px);line-height:1.12;letter-spacing:-.02em}.landing-title-en{display:block;margin-top:6px;font-size:clamp(13px,2.2vw,16px);font-weight:500;letter-spacing:.16em;text-transform:uppercase;color:var(--muted)}.landing-lead{margin:20px auto 0;max-width:52ch;font-size:clamp(15px,2.4vw,17px);line-height:1.75;color:var(--muted)}.landing-lead strong{color:var(--fg)}.landing-cta{margin-top:30px;padding:13px 34px;border:none;border-radius:999px;background:var(--accent);color:#fff;font-size:15.5px;font-weight:600;cursor:pointer;transition:transform .12s ease,filter .12s ease}.landing-cta:hover{transform:translateY(-1px);filter:brightness(1.08)}.landing-stats{margin:40px 0 0;display:grid;grid-template-columns:repeat(4,1fr);gap:10px}.landing-stats>div{padding:14px 8px;border:1px solid var(--line);border-radius:12px;background:var(--card)}.landing-stats dt{font-size:12px;color:var(--muted)}.landing-stats dd{margin:4px 0 0;font-size:22px;font-weight:700}.landing-note{margin-top:22px;font-size:12.5px;color:var(--muted)}@media(max-width:520px){.landing-stats{grid-template-columns:repeat(2,1fr)}}.hub-head h2{margin:0;font-size:24px;letter-spacing:-.01em}.hub-head>p{margin:6px 0 0;color:var(--muted);font-size:14px}.hub-overall{margin-top:16px;display:flex;align-items:center;gap:12px;flex-wrap:wrap}.hub-overall-text{font-size:13px;color:var(--muted)}.hub-bar{flex:1 1 180px;min-width:120px;height:6px;border-radius:999px;background:var(--line);overflow:hidden}.hub-bar>span{display:block;height:100%;background:var(--accent);border-radius:999px}.hub-section{margin-top:34px}.hub-step{display:flex;align-items:baseline;gap:10px;flex-wrap:wrap;margin-bottom:14px}.hub-step-num{padding:2px 9px;border-radius:999px;background:var(--accent);color:#fff;font-size:11px;font-weight:700;letter-spacing:.06em}.hub-step-title{font-size:17px;font-weight:700}.hub-step-sub{font-size:13px;color:var(--muted)}.hub-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(250px,1fr));gap:14px}.hub-card{display:flex;flex-direction:column;align-items:flex-start;gap:8px;padding:18px;border:1px solid var(--line);border-radius:14px;background:var(--card);color:var(--fg);text-align:left;cursor:pointer;transition:border-color .12s ease,transform .12s ease}.hub-card:hover{border-color:var(--accent);transform:translateY(-2px)}.hub-card h3{margin:0;font-size:16px;line-height:1.4}.hub-card p{margin:0;font-size:13px;color:var(--muted);line-height:1.6}.hub-card-badge{padding:2px 8px;border-radius:6px;background:var(--bg);border:1px solid var(--line);font-size:11px;color:var(--muted)}.hub-card--module .hub-card-badge{background:var(--accent);color:#fff;border-color:transparent}.hub-card-meta{font-size:12px;color:var(--muted)}.hub-card-cta{margin-top:2px;font-size:13px;font-weight:600;color:var(--accent)}.hub-card .hub-bar{width:100%;flex:none}.hub-tiers{display:flex;gap:5px;flex-wrap:wrap}.hub-tier{padding:2px 7px;border-radius:6px;font-size:11px;border:1px solid var(--line)}.hub-tier--intro{color:var(--correct)}.hub-tier--core{color:var(--accent)}.hub-tier--adv{color:var(--wrong)}.hub-all{margin-top:14px;padding:9px 16px;border:1px dashed var(--line);border-radius:10px;background:transparent;color:var(--muted);font-size:13px;cursor:pointer}.hub-all:hover{border-color:var(--accent);color:var(--accent)}.hub-empty{color:var(--muted);font-size:13px}.study-filters{display:grid;gap:8px;padding:12px;border:1px solid var(--line);border-radius:12px;background:var(--card);margin-bottom:16px}.filter-row{display:flex;align-items:center;gap:6px;flex-wrap:wrap}.filter-label{font-size:12px;color:var(--muted);min-width:42px}.filter-row button{padding:4px 11px;border:1px solid var(--line);border-radius:999px;background:var(--bg);color:var(--fg);font-size:12.5px;cursor:pointer}.filter-row button:hover{border-color:var(--accent)}.filter-row button.on{background:var(--accent);color:#fff;border-color:transparent}.study-progress{display:flex;align-items:center;gap:10px;margin-bottom:14px;font-size:12.5px;color:var(--muted)}.tier-chip{padding:1px 7px;border-radius:6px;border:1px solid var(--line);font-size:11.5px}.tier-chip--intro{color:var(--correct)}.tier-chip--core{color:var(--accent)}.tier-chip--adv{color:var(--wrong)}.seen-chip{margin-left:8px;padding:1px 7px;border-radius:999px;font-size:11px;border:1px solid var(--line)}.seen-chip--correct{color:var(--correct)}.seen-chip--wrong{color:var(--wrong)}.empty-inline{color:var(--muted);font-size:14px}@media(prefers-color-scheme:dark){.landing-cta,.hub-step-num,.hub-card--module .hub-card-badge,.filter-row button.on{color:#14161a}}:root[data-theme=dark] .landing-cta,:root[data-theme=dark] .hub-step-num,:root[data-theme=dark] .hub-card--module .hub-card-badge,:root[data-theme=dark] .filter-row button.on{color:#14161a}:root[data-theme=light] .landing-cta,:root[data-theme=light] .hub-step-num,:root[data-theme=light] .hub-card--module .hub-card-badge,:root[data-theme=light] .filter-row button.on{color:#fff}.drill-head{display:flex;align-items:flex-start;justify-content:space-between;gap:16px;flex-wrap:wrap}.drill-head h2{margin:0;font-size:22px}.drill-head p{margin:5px 0 0;font-size:13.5px;color:var(--muted)}.drill-score{display:flex;align-items:center;gap:10px;font-size:14px;color:var(--muted)}.drill-score strong{font-size:22px;color:var(--fg)}.drill-score button{padding:5px 11px;border:1px solid var(--line);border-radius:999px;background:var(--bg);color:var(--muted);font-size:12.5px;cursor:pointer}.drill-score button:hover{border-color:var(--accent);color:var(--accent)}.drill-meta{margin:14px 0 6px;font-size:12.5px;color:var(--muted)}.drill-prompt{margin:14px 0 10px;font-size:16px;font-weight:600}.drill-choices{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(auto-fit,minmax(140px,1fr));gap:10px}.drill-choices button{width:100%;display:flex;align-items:center;gap:10px;padding:14px 16px;border:1px solid var(--line);border-radius:12px;background:var(--bg);color:var(--fg);font-size:17px;font-weight:600;cursor:pointer;transition:border-color .12s ease}.drill-choices button:hover:enabled{border-color:var(--accent)}.drill-choices button.correct{border-color:var(--correct);color:var(--correct)}.drill-choices button.wrong{border-color:var(--wrong);color:var(--wrong)}.drill-feedback{margin-top:16px;padding:14px 16px;border:1px solid var(--line);border-radius:12px;background:var(--card)}.drill-feedback p{margin:0 0 6px}.drill-feedback .ok{color:var(--correct);font-weight:700}.drill-feedback .no{color:var(--wrong);font-weight:700}.drill-why{font-size:14px;line-height:1.7;margin-bottom:8px}.drill-elements{font-size:13px;color:var(--muted);font-family:ui-monospace,monospace}.hub-card--drill{text-decoration:none}.app-brand{display:inline-flex;align-items:center;gap:8px;font-weight:700;text-decoration:none;color:var(--fg)}.app-brand-mark{display:grid;place-items:center;width:26px;height:26px;border-radius:8px;background:var(--accent);color:#fff;font-size:12px;font-weight:700}.admin-flag{padding:3px 10px;border-radius:999px;background:var(--wrong);color:#fff;font-size:12px;font-weight:600}.admin-footer{margin-top:28px;padding:12px 16px;border-top:1px solid var(--line);font-size:12.5px;color:var(--muted)}