*{margin:0;padding:0;box-sizing:border-box;font-family:"Helvetica Neue", Helvetica, Arial, sans-serif;}
body{background-color:#f5f5f5;color:#333;line-height:1.6;}
a{text-decoration:none;color:#444;transition:all 0.3s;}
a:hover{color:#3498db;}
ul{list-style:none;}
.container{width:100%;max-width:1000px;margin:0 auto;}
button{cursor:pointer;border:none;background:none;}
input:focus{outline:none;}
.header{background-color:rgb(240, 245, 249);padding:10px 0;}
.nav{display:flex;align-items:center;width:100%;max-width:800px;margin:0 auto;position:relative;padding:0 15px;}
.logo-container{display:flex;flex-direction:column;align-items:center;line-height:1;}
.logo{font-size:20px;font-weight:bold;color:#3498db;white-space:nowrap;margin-right:0px;text-decoration:none;transition:color 0.3s ease;line-height:1.2;}
.logo:hover{color:#e74c3c;}
.logo-url{font-size:12px;color:#666;margin-top:0px;white-space:nowrap;}
.search-wrapper{display:flex;align-items:center;transition:all 0.3s;}
.search-form{display:flex;align-items:center;width:100%;}
.search-input{padding:8px 15px;border-radius:20px;border:none;width:80%;max-width:300px;font-size:14px;}
.search-btn{background-color:#3498db;color:white;padding:8px 15px;border-radius:20px;margin-left:10px;transition:background-color 0.3s;white-space:nowrap;}
.search-btn:hover{background-color:#2980b9;}
.nav-links{display:flex;align-items:center;}
.nav-links li{margin:0 10px;}
.nav-links a{font-size:15px;white-space:nowrap;}
.banner{background-color:#3498db;padding:40px 0;text-align:center;color:#fff;}
.banner p{font-size:18px;opacity:0.9;}
.main-content{display:flex;}
.section{margin-top:20px;background-color:#fff;border-radius:8px;box-shadow:0 2px 8px rgba(0,0,0,0.1);}
.section-title{padding:6px 20px;color:#fff;border-radius:8px;background:rgb(25, 181, 251);font-size:16px;}
.pdf-list{display:flex;flex-wrap:wrap;padding:10px 10px 0 10px;}
.pdf-card{width:25%;padding:0 5px 20px;}
.pdf-card-inner{border-radius:6px;padding:5px;transition:transform 0.3s;height:100%;}
.pdf-card-inner:hover{transform:translateY(-5px);box-shadow:0 5px 15px rgba(0,0,0,0.1);}
.pdf-title{margin-bottom:8px;overflow:hidden;text-overflow:ellipsis;font-size:15px;transition:color 0.3s;}
.pdf-title:hover{color:#3498db;}
.click-container{display:flex;align-items:center;}
.pdf-click{color:#e74c3c;font-weight:bold;font-size:16px;}
.click-beautify{color:#3498db;margin-left:5px;font-size:14px;opacity:0.8;}
.two-columns{padding-bottom:10px;}
.two-columns .pdf-card{width:50%;padding:0px;}
.two-columns .pdf-card-inner{display:flex;justify-content:space-between;align-items:center;padding:10px 15px;border-radius:8px;transition:all 0.3s ease;}
.two-columns .pdf-card-inner:hover{transform:translateY(0);box-shadow:0 3px 10px rgba(52, 152, 219, 0.15);border-color:#bde0fe;}
.two-columns .pdf-title{margin-bottom:0;font-size:14px;flex:1;line-height:1.4;}
.two-columns .click-container{min-width:38px;justify-content:flex-end;}
.two-columns .pdf-click{font-size:15px;}
.two-columns .pdf-card-inner .rank-num{display:inline-block;width:22px;height:22px;line-height:22px;text-align:center;color:#fff;font-size:12px;font-weight:bold;border-radius:50%;margin-right:8px;}
.two-columns .pdf-card:nth-child(1) .rank-num{background-color:#FF6B6B;}
.two-columns .pdf-card:nth-child(2) .rank-num{background-color:#4ECDC4;}
.two-columns .pdf-card:nth-child(3) .rank-num{background-color:#45B7D1;}
.two-columns .pdf-card:nth-child(4) .rank-num{background-color:#96CEB4;}
.two-columns .pdf-card:nth-child(5) .rank-num{background-color:#FFEAA7;}
.two-columns .pdf-card:nth-child(6) .rank-num{background-color:#DDA0DD;}
.two-columns .pdf-card:nth-child(7) .rank-num{background-color:#FFA07A;}
.two-columns .pdf-card:nth-child(8) .rank-num{background-color:#87CEEB;}
.two-columns .pdf-card:nth-child(9) .rank-num{background-color:#F08080;}
.two-columns .pdf-card:nth-child(10) .rank-num{background-color:#98D8C8;}
.footer{margin-top:30px;background-color:rgb(240, 245, 249);color:#333;padding:30px 0;text-align:center;}
.footer-info{margin-bottom:15px;font-size:14px;}
.footer-copyright{font-size:13px;}
.footer a{color:#007bff;}
@media (max-width: 992px){
.pdf-card{width:33.333%;}
}
@media (max-width: 768px){
.two-columns .pdf-card-inner{padding:8px 5px;}
.search-wrapper{position:absolute;left:0!important;right:0!important;top:calc(100% + 15px);background-color:rgb(240, 245, 249);padding:10px 15px;border-radius:4px;box-shadow:0 2px 8px rgba(0,0,0,0.2);z-index:10;width:100%!important;margin:0!important;}
.search-input{max-width:none;}
.nav-links{position:absolute;left:50%;transform:translateX(-20%);margin:0;padding:0;}
.main-content{flex-direction:column;}
.banner{margin-top:60px;}
.banner p{font-size:16px;}
.pdf-card{width:50%;}
.two-columns .pdf-card{width:100%;}
.two-columns .pdf-title{font-size:13px;}
}
@media (max-width: 576px){
.logo{font-size:16px;}
.logo-url{font-size:10px;}
.search-input{padding:6px 10px;font-size:13px;}
.nav-links a{font-size:13px;}
.banner{padding:25px 0;}
}
@media (min-width: 769px){
.search-wrapper{display:flex;margin-left:20px;}
.nav-links{margin:0 auto;}
.header{position:fixed;top:0;left:0;right:0;z-index:1000;}
body{padding-top:50px;}
}