.container{max-width:1200px;margin:0 auto;padding:0 20px}.page-header{background:linear-gradient(135deg,#3498db,#2c3e50);color:white;padding:40px 0;text-align:center;margin-bottom:40px}.page-header h1{font-size:36px;margin-bottom:15px}.page-header p{font-size:18px;max-width:700px;margin:0 auto;line-height:1.6}.active{color:#3498db!important;border-bottom:2px solid #3498db;padding-bottom:5px}.category-nav{background-color:white;border-radius:10px;padding:20px;margin-bottom:40px;box-shadow:0 5px rgba(0,0,0,.05)}.category-nav h2{font-size:20px;margin-bottom:15px;color:#2c3e50}.category-list{display:flex;flex-wrap:wrap;gap:15px}.category-item{border:2px solid #e1f0fe;border-radius:30px;padding:10px 20px;font-weight:500;cursor:pointer;transition:all .3s;color:#3498db}.materials-section{margin-bottom:60px}.section-title{font-size:24px;margin-bottom:25px;padding-bottom:15px;border-bottom:2px solid #979797;color:#2c3e50;display:flex;align-items:center}.section-title i{margin-right:10px;color:#3498db;font-size:24px}.materials-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(350px,1fr));gap:30px}.materials-card{background-color:white;border-radius:10px;overflow:hidden;box-shadow:0 5px 15px rgba(0,0,0,.05);transition:transform .3s,box-shadow .3s}.materials-card:hover{transform:translateY(-5px);box-shadow:0 10px 20px rgba(0,0,0,.1)}.card-image{height:180px;background-size:cover;background-position:50%;position:relative}.card-image:after{content:"";position:absolute;bottom:0;left:0;width:100%;height:60px;background:linear-gradient(0deg,rgba(0,0,0,.7),transparent)}.card-content{padding:20px}.card-meta{display:flex;justify-content:space-between;font-size:13px;color:#7f8c8d}.card-button{display:inline-block;background-color:#3498db;color:white;margin-top:10px;padding:8px 16px;border-radius:5px;text-decoration:none;font-weight:500;font-size:14px;transition:background-color .3s}