.elements-container-wrapper{background-color:#f0f4f8;padding:40px 20px;min-height:100vh;display:flex;justify-content:center;align-items:flex-start;background-image:url(/images/chemistry-background.png);background-size:cover;background-position:50%;background-repeat:no-repeat;box-sizing:border-box}.elements-container{width:100%;max-width:1500px;padding:0 20px 20px;background-color:#fff;border-radius:12px;box-shadow:0 6px 18px rgba(0,0,0,.12);text-align:left;box-sizing:border-box}.elements-title{font-size:32px;display:flex;align-items:center;gap:15px;margin-top:0;margin-bottom:10px;flex-wrap:wrap}@media (max-width:768px){.elements-title{flex-direction:column;align-items:flex-start;gap:8px}}.start-exercises-btn{font-size:.9rem;background-color:#55a160;color:#fff;padding:8px 16px;border-radius:8px;font-weight:600;text-decoration:none;cursor:pointer;transition:background .2s ease,transform .2s ease}.start-exercises-btn:hover{background-color:#3f8a4d;transform:translateY(-1px)}.start-exercises-btn:active{transform:translateY(0)}.atoms-category-wrapper{display:flex;flex-wrap:wrap;justify-content:center;gap:20px;padding:20px 0}.atoms-category-box{flex:1 1 calc(25% - 20px);max-width:300px;border:1px solid #dee2e6;border-radius:8px;background-color:#f8f9fa}@media (max-width:768px){.atoms-category-box{flex:1 1 100%;max-width:100%}}.atoms-category-title{font-size:16px;font-weight:700;text-align:center;background-color:#e9ecef;padding:10px;border-radius:8px 8px 0 0}.atoms-button{display:flex;justify-content:space-between;align-items:center;width:100%;padding:10px 14px;margin:8px 0;background-color:#5d74b3;color:#fff;text-decoration:none;border-radius:6px;box-sizing:border-box;transition:background-color .2s ease}.atoms-button:hover{background-color:#005f99;color:#fff}.completion-star{width:20px;height:20px;margin-left:10px;flex-shrink:0}.elements-heading-2{font-size:25px;font-weight:700;margin-bottom:15px;color:#0077b6}.elements-text-2{font-size:18px;line-height:1.55;margin-bottom:15px;color:#333}.elements-list-2{font-size:18px;margin-left:20px}.elements-list-item-2{margin-bottom:12px}.exercise-page-header{margin-top:10px}.exercise-learning-panel{background:linear-gradient(180deg,#f8fcff,#eef6fb);border:1px solid #d8e6ef;border-radius:14px;margin:22px 0 26px;padding:22px}.exercise-learning-panel h2{color:#2c3e50;font-size:1.35rem;margin:0 0 12px}.exercise-learning-panel p{color:#334155;line-height:1.65;margin:0 0 12px}.exercise-learning-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px;margin-top:16px}.exercise-learning-card{background-color:#fff;border:1px solid #e3edf3;border-radius:12px;padding:16px}.exercise-learning-card h3{color:#005f73;font-size:1rem;margin:0 0 8px}.exercise-learning-card p{margin:0}.quiz-crawl-summary{background:#f8fafc;border:1px solid #d8e6ef;border-radius:10px;color:#334155;font-size:.95rem;line-height:1.55;margin:0 auto 18px;max-width:760px;padding:12px 14px;text-align:left}.quiz-crawl-summary summary{color:#005f73;cursor:pointer;font-weight:700}.quiz-crawl-summary ol,.quiz-crawl-summary ul{max-height:190px;margin:10px 0 0 22px;overflow:auto;padding:0}.quiz-crawl-summary li{margin-bottom:6px}.test-text{margin-bottom:25px}.test-heading{font-size:28px;color:#0077b6;margin-bottom:15px}.test-paragraph{font-size:16px;line-height:1.5;margin-bottom:10px}.hub-intro-panel{margin:18px 0 12px}.hub-info-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px}.hub-info-card{background:linear-gradient(180deg,#f8fcff,#eef6fb);border:1px solid #d8e6ef;border-radius:14px;padding:18px;text-align:left}.hub-info-title{font-size:1rem;font-weight:700;color:#2c3e50;margin:0 0 8px}.hub-info-text{margin:0;color:#3a4757;line-height:1.6}.hub-info-text a{color:#0f766e;font-weight:700;text-decoration:none}.hub-info-text a:hover{text-decoration:underline}.d-flex{display:flex;justify-content:center;margin-top:35px}@media (max-width:768px){.elements-container-wrapper{width:100%;padding-left:20px;padding-right:20px}.elements-container{width:calc(100vw - 40px)!important;max-width:calc(100vw - 40px)!important;padding:24px 18px;border-radius:0}.description-block,.elements-container-2,.exercise-box{max-width:100%;box-sizing:border-box}.hub-info-grid{grid-template-columns:1fr}.exercise-learning-panel{padding:18px}.exercise-learning-grid{grid-template-columns:1fr}}