#about {
   background: linear-gradient(rgba(17, 36, 90, 0.5), rgba(17, 36, 90, 0.5)), url("../img/hero_img.jpg") center/cover no-repeat;
   background-attachment: fixed;
   min-height: 100vh;
}

#feature {
   background: linear-gradient(rgba(17, 36, 90, 0.5), rgba(17, 36, 90, 0.5)), url("../img/p5.jpg") center/cover no-repeat;
   background-attachment: fixed;
   min-height: 75vh;
}

.section-title {
   position: relative;
   padding-bottom: 15px;
   margin-bottom: 30px;
}

.section-title:after {
   content: "";
   position: absolute;
   bottom: 0;
   left: 50%;
   transform: translateX(-50%);
   width: 80px;
   height: 3px;
   background: #ffffff;
}

.feature-card {
   border-radius: 15px;
   padding: 30px;
   height: 100%;
   transition: all 0.3s ease;
}

.feature-card:hover {
   transform: translateY(-10px);
   box-shadow: 0 15px 30px rgba(0, 0, 0, 0.2);
}

/* 导航栏激活状态样式（更自然的下划线风格） */
.navbar-nav .nav-link {
   position: relative;
   transition: color 0.22s ease, background-color 0.22s ease;
   padding: 0.5rem 0.9rem;
   border-radius: 6px;
   color: #333333;
}

/* 使用细线下划作为激活指示，避免整块高亮看起来突兀 */
.navbar-nav .nav-link::after {
   content: "";
   position: absolute;
   bottom: 6px;
   left: 50%;
   transform: translateX(-50%);
   width: 0;
   height: 2px;
   background: #0b5ed7;
   border-radius: 2px;
   transition: width 0.28s cubic-bezier(.2,.8,.2,1), opacity 0.2s;
   opacity: 0;
}

.navbar-nav .nav-link.active {
   color: #0b5ed7 !important;
   font-weight: 600;
   background-color: transparent;
}

.navbar-nav .nav-link.active::after {
   width: 36%;
   opacity: 1;
}

.navbar-nav .nav-link:hover {
   color: #0b5ed7 !important;
   background-color: rgba(11, 94, 215, 0.04);
}

.navbar-nav .nav-link:hover::after {
   width: 28%;
   opacity: 0.85;
}