.header-content{width:min(100%,var(--max-width));margin:0 auto;padding:0 .8rem;display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:.5rem}.header-stats{display:flex;gap:.6rem;align-items:center;flex-wrap:wrap}.stat-badge{border:2px solid var(--border-color);border-radius:var(--border-corners);padding:.35rem .75rem;font-size:1.15rem;font-weight:700;background-color:var(--bg-card)}.card{background-color:var(--bg-card);border:2px solid var(--border-color);border-radius:var(--border-corners);padding:1.25rem;display:flex;flex-direction:column;gap:1.25rem}.controls-row{display:flex;flex-wrap:wrap;gap:.75rem;align-items:flex-end}.control-group{display:flex;flex-direction:column;gap:.25rem;flex:1;min-width:200px}.control-label{font-size:1rem;font-weight:700;color:var(--text-muted)}.select-control{font-family:inherit;font-size:1.15rem;font-weight:700;padding:.55rem .8rem;background-color:var(--bg-card);color:var(--text-color);border:2px solid var(--border-color);border-radius:var(--border-corners);box-shadow:2px 3px 0 var(--shadow-color);outline:none;cursor:pointer;width:100%}.select-control:focus,.select-control:hover{border-color:var(--purple-primary)}.question-box{text-align:center;padding:1rem .5rem;border-top:2px dashed var(--border-color);border-bottom:2px dashed var(--border-color);display:flex;flex-direction:column;align-items:center;gap:.5rem}.question-label{font-size:1.3rem;color:var(--text-muted)}.question-target-text{font-size:2.6rem;font-weight:700;color:var(--purple-primary);letter-spacing:.02em;word-break:break-word}.text-input{width:100%;max-width:480px;padding:.85rem 1rem;font-size:1.4rem;font-weight:700;font-family:inherit;color:var(--purple-primary);border:2px solid var(--border-color);border-radius:var(--border-corners);background-color:var(--bg-color);box-shadow:inset 2px 3px 5px #0000000a;outline:none;text-align:center;transition:all .2s ease}.text-input:focus{border-color:var(--purple-primary);background-color:var(--bg-card)}.text-input.correct{border-color:var(--green-base);background-color:#4e803214}.text-input.incorrect{border-color:var(--red-base);background-color:#ca524514}.structure-canvas-wrapper{width:100%;max-width:480px;height:220px;background-color:#fff;border-radius:var(--border-corners);display:flex;align-items:center;justify-content:center;padding:.5rem;overflow:hidden}.structure-canvas-wrapper svg{width:100%;height:100%}.grid-options{display:grid;grid-template-columns:repeat(2,1fr);gap:.85rem}@media(max-width:680px){.grid-options{grid-template-columns:1fr}}.option-btn{display:flex;align-items:center;gap:.75rem;text-align:left;width:100%;min-height:70px;padding:.75rem 1rem;border:2px solid var(--border-color);border-radius:var(--border-corners);box-shadow:3px 4px 0 var(--shadow-color);background-color:var(--bg-card);font-family:inherit;font-size:1.2rem;font-weight:700;color:var(--text-color);cursor:pointer;transition:all .15s ease}.option-btn:hover{border-color:var(--purple-primary);transform:translateY(-2px);box-shadow:4px 6px 0 var(--shadow-color)}.option-badge{display:flex;align-items:center;justify-content:center;width:32px;height:32px;min-width:32px;border-radius:50%;background-color:#5a4a781f;color:var(--purple-primary);font-weight:700;font-size:1.1rem}.option-content{flex:1;display:flex;align-items:center;justify-content:flex-start;overflow:hidden}.option-structure-box{width:100%;height:130px;display:flex;align-items:center;justify-content:center}.formula-option{position:relative;min-height:180px;padding:0;overflow:hidden}.formula-option .option-structure-box{height:180px;background-color:#fff}.formula-option-badge{position:absolute;top:.6rem;left:.6rem;z-index:1;background-color:#fff}.option-structure-box svg{width:100%;height:100%}.feedback-panel{border:2px solid var(--border-color);border-radius:var(--border-corners);padding:1.25rem;box-shadow:3px 4px 0 var(--shadow-color);display:none;margin-top:.25rem}.feedback-correct{background-color:#4e80321f;border-color:var(--green-base)}.feedback-incorrect{background-color:#ca52451f;border-color:var(--red-base)}.feedback-header{display:flex;align-items:center;gap:.75rem;font-size:1.35rem;font-weight:700}.feedback-details{margin-top:.75rem;padding-top:.75rem;border-top:1px dashed var(--border-color);font-size:1.15rem;display:flex;flex-direction:column;gap:.4rem}.explanation-text{margin-top:.4rem;font-style:italic;color:var(--text-muted)}.modal-overlay{position:fixed;inset:0;background:#0000008c;z-index:100;display:flex;align-items:center;justify-content:center;padding:1rem;opacity:0;pointer-events:none;transition:opacity .2s ease}.modal-overlay.active{opacity:1;pointer-events:auto}.modal-card{background:var(--bg-card);border:2px solid var(--border-color);border-radius:var(--border-corners);max-width:700px;width:100%;max-height:88vh;display:flex;flex-direction:column;overflow:hidden}.modal-header{padding:1rem 1.25rem;border-bottom:2px solid var(--border-color);display:flex;align-items:center;justify-content:space-between}.modal-body{padding:1.25rem;overflow-y:auto}.modal-footer{padding:1rem 1.25rem;border-top:2px solid var(--border-color);display:flex;justify-content:flex-end}.cat-checkbox-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(230px,1fr));gap:.6rem}.cat-checkbox-item{display:flex;align-items:center;gap:.75rem;padding:.6rem .8rem;border-radius:var(--border-corners);border:2px solid var(--border-color);background:var(--bg-card);cursor:pointer;font-weight:700;font-size:1.1rem;transition:all .15s ease}.cat-checkbox-item:hover{border-color:var(--purple-primary)}.cat-checkbox-item input{width:20px;height:20px;cursor:pointer;accent-color:var(--purple-primary)}footer{margin-top:auto;padding:1rem;text-align:center;font-size:1.05rem;color:var(--text-muted)}