:root{--primary: #2c3e50;--primary-light: #34495e;--accent: #e74c3c;--omr-bg: #fffcf2;--omr-border: #d4d4d4;--marking-color: #1a1a1a;--success: #27ae60;--warning: #f1c40f;--background: #f0f2f5;--card-shadow: 0 10px 25px rgba(0, 0, 0, .1)}body{font-family:Pretendard,-apple-system,BlinkMacSystemFont,system-ui,Roboto,sans-serif;background-color:var(--background);color:#333;line-height:1.6}.app-container{max-width:1200px;margin:0 auto;padding:20px}header{margin-bottom:40px;text-align:center}header h1{font-size:2.5rem;color:var(--primary);font-weight:800;letter-spacing:-1px}.level-selector{display:flex;justify-content:center;flex-wrap:wrap;gap:12px;margin-bottom:50px}.level-button{padding:12px 24px;border-radius:12px;border:2px solid white;background:#fff;box-shadow:0 4px 6px #0000000d;cursor:pointer;font-weight:600;transition:all .3s cubic-bezier(.4,0,.2,1)}.level-button:hover{transform:translateY(-2px);box-shadow:0 6px 12px #0000001a}.level-button.active{background:var(--primary);color:#fff;border-color:var(--primary)}.main-content{display:grid;grid-template-columns:1fr 400px;gap:40px;align-items:start}.left-panel{background:#fff;border-radius:12px;padding:0;overflow:visible}.right-panel{position:sticky;top:20px}.omr-card{background:var(--omr-bg);border:2px solid var(--omr-border);border-radius:4px;padding:30px 20px;box-shadow:0 5px 15px #0000000d;position:relative}.omr-card:before{content:"";position:absolute;left:10px;top:0;bottom:0;width:2px;background:repeating-linear-gradient(to bottom,var(--omr-border),var(--omr-border) 10px,transparent 10px,transparent 20px)}.omr-header{text-align:center;border-bottom:2px solid var(--primary);margin-bottom:25px;padding-bottom:15px}.omr-header h2{font-family:serif;font-size:1.8rem;font-weight:800;color:var(--primary);text-decoration:underline}.problem-list{display:grid;grid-template-columns:1fr;gap:12px;padding-right:10px}.problem-list::-webkit-scrollbar{width:6px}.problem-list::-webkit-scrollbar-thumb{background:var(--omr-border);border-radius:10px}.problem-item{display:grid;grid-template-columns:40px 1fr;align-items:center;gap:10px;padding:8px 0;border-bottom:1px dashed #eee}.problem-no{font-weight:700;font-size:.9rem;color:#666;text-align:right;padding-right:8px}.options-row{display:flex;justify-content:space-between;padding-right:10px}.omr-bubble{width:32px;height:22px;border:1px solid #777;border-radius:50%;background:#fff;cursor:pointer;display:flex;align-items:center;justify-content:center;font-size:.75rem;font-weight:600;color:#777;position:relative;transition:all .1s}.omr-bubble:hover{background:#fdfdfd}.omr-bubble.selected{background:var(--marking-color);color:var(--marking-color);border-color:var(--marking-color);box-shadow:inset 0 0 5px #00000080}.omr-bubble.selected:after{content:"";position:absolute;width:80%;height:140%;background:var(--marking-color);border-radius:30%;opacity:.9}.omr-submit{margin-top:25px;width:100%;padding:16px;background:var(--primary);color:#fff;border:none;border-radius:8px;font-size:1.1rem;font-weight:700;cursor:pointer;transition:background .2s}.omr-submit:hover{background:var(--primary-light)}.result-banner{background:#fff;border:4px solid var(--success);border-radius:16px;padding:30px;text-align:center;margin-bottom:30px;animation:slideDown .5s ease}@keyframes slideDown{0%{opacity:0;transform:translateY(-20px)}to{opacity:1;transform:translateY(0)}}.score-badge{display:inline-block;font-size:3rem;font-weight:900;color:var(--success);background:#eafaf1;padding:10px 30px;border-radius:100px;margin:15px 0}.pdf-tabs{display:flex;background:#eee;padding:5px;border-radius:12px;width:fit-content}.pdf-tab{padding:10px 20px;border:none;background:transparent;border-radius:8px;font-weight:700;cursor:pointer;transition:all .2s;color:#666}.pdf-tab.active{background:#fff;color:var(--primary);box-shadow:0 2px 4px #0000001a}.omr-bubble.correct{border-color:var(--success);color:var(--success);background:#fff;box-shadow:0 0 0 2px #27ae6033}.omr-bubble.wrong{border-color:var(--accent);color:var(--accent);background:#fff}.omr-bubble.correct.selected{background:var(--success);border-color:var(--success);color:#fff}.omr-bubble.wrong.selected{background:var(--accent);border-color:var(--accent);color:#fff}.omr-bubble:not(:disabled):hover{transform:scale(1.1);border-color:var(--marking-color)}@media screen and (max-width:1024px){.main-content{display:flex;flex-direction:column;gap:20px}.right-panel{position:static;margin-top:20px}header h1{font-size:2rem}header p{font-size:1rem!important}.mobile-hidden{display:none!important}.mobile-visible{display:block!important}}@media screen and (max-width:480px){.app-container{padding:10px}.level-button{padding:10px 16px;font-size:.9rem}.omr-card{padding:20px 10px}.options-row{padding-right:0}.omr-bubble{width:28px;height:28px}.result-banner{padding:20px 15px}.score-badge{font-size:2rem;padding:5px 20px}}.mobile-omr-toggle{display:none;position:fixed;bottom:20px;right:20px;width:60px;height:60px;border-radius:50%;background:var(--primary);color:#fff;border:none;box-shadow:0 4px 15px #0000004d;z-index:1000;font-size:1.5rem;cursor:pointer;align-items:center;justify-content:center;transition:transform .2s}.mobile-omr-toggle:active{transform:scale(.9)}@media screen and (max-width:1024px){.mobile-omr-toggle{display:flex}}