/* ========== 基础 ========== */
* { scroll-behavior: smooth; }
html { -ms-overflow-style: none; scrollbar-width: none; }
::-webkit-scrollbar { display: none; }

body {
    font-family: 'Inter', 'PingFang SC', 'Microsoft YaHei', sans-serif;
    background: #F4F7FA;
    color: #121A22;
    overflow-x: hidden;
}

/* ========== 鼠标光晕 ========== */
#cursor-glow {
    position: fixed;
    width: 420px;
    height: 420px;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(0, 180, 216, 0.18), rgba(0, 180, 216, 0) 60%);
    pointer-events: none;
    z-index: 1;
    transform: translate(-50%, -50%);
    transition: opacity 0.4s ease;
}

/* ========== 进度条 ========== */
#progressBar {
    position: fixed;
    top: 0;
    left: 0;
    height: 3px;
    background: linear-gradient(90deg, #00B4D8, #72E1F0);
    z-index: 60;
    width: 0%;
    transition: width 0.1s linear;
}

/* ========== Header 导航 ========== */
.nav-link {
    position: relative;
    color: rgba(255, 255, 255, 0.86);
    transition: color 0.3s ease;
}
.nav-link::after {
    content: "";
    position: absolute;
    left: 0;
    bottom: -6px;
    width: 0;
    height: 2px;
    background: linear-gradient(90deg, #00B4D8, #72E1F0);
    transition: width 0.35s ease;
}
.nav-link:hover { color: #fff; }
.nav-link:hover::after { width: 100%; }
.nav-link.active { color: #72E1F0; font-weight: 600; }
.nav-link.active::after { width: 100%; }

/* 移动端菜单 */
#mobileMenu {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease;
}
#mobileMenu.open { max-height: 460px; }

/* ========== 按钮 ========== */
.btn-primary {
    position: relative;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #00B4D8, #0096B7);
    color: #fff;
    padding: 14px 34px;
    border-radius: 999px;
    font-weight: 600;
    letter-spacing: 0.3px;
    box-shadow: 0 10px 24px -10px rgba(0, 180, 216, 0.55);
    transition: transform 0.35s ease, box-shadow 0.35s ease, filter 0.35s ease;
    overflow: hidden;
}
.btn-primary:hover {
    transform: translateY(-3px);
    filter: brightness(1.08);
    box-shadow: 0 18px 34px -12px rgba(0, 180, 216, 0.7);
}
.btn-primary::before {
    content: "";
    position: absolute;
    top: 0; left: -80px;
    width: 60px; height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.35), transparent);
    transition: left 0.6s ease;
}
.btn-primary:hover::before { left: 120%; }

/* 活动页报名按钮（方块） */
.btn-square {
    display: inline-block;
    background: #009292;
    color: #fff;
    padding: 12px 32px;
    border-radius: 8px;
    font-weight: 500;
    text-align: center;
    transition: all 0.3s ease;
}
.btn-square:hover {
    background: #007878;
    transform: translateY(-2px);
}

/* ========== 卡片 ========== */
.card-hover {
    background: #fff;
    border: 1px solid rgba(12, 32, 40, 0.08);
    border-radius: 22px;
    padding: 28px;
    transition: transform 0.4s ease, box-shadow 0.4s ease, border-color 0.4s ease;
    position: relative;
    overflow: hidden;
}
.card-hover::before {
    content: "";
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, rgba(0, 180, 216, 0.12), transparent 55%);
    opacity: 0;
    transition: opacity 0.4s ease;
    pointer-events: none;
}
.card-hover:hover {
    transform: translateY(-8px);
    border-color: rgba(0, 180, 216, 0.45);
    box-shadow: 0 30px 50px -30px rgba(0, 180, 216, 0.45);
}
.card-hover:hover::before { opacity: 1; }

/* ========== 标题 ========== */
.section-title {
    position: relative;
    display: inline-block;
    font-weight: 700;
    letter-spacing: 1px;
}
.section-title::after {
    content: "";
    position: absolute;
    left: 0;
    bottom: -10px;
    width: 48px;
    height: 4px;
    border-radius: 4px;
    background: linear-gradient(90deg, #00B4D8, #72E1F0);
}

/* ========== 滚动淡入 ========== */
.reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.9s ease, transform 0.9s ease;
}
.reveal.show {
    opacity: 1;
    transform: translateY(0);
}

/* ========== 侧边工具 ========== */
.side-tool {
    position: fixed;
    right: 20px;
    bottom: 140px;
    z-index: 50;
    display: flex;
    flex-direction: column;
    gap: 14px;
}
.side-tool a {
    width: 54px;
    height: 54px;
    border-radius: 50%;
    background: linear-gradient(135deg, #00B4D8, #0096B7);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 22px;
    box-shadow: 0 10px 24px -10px rgba(0, 180, 216, 0.6);
    transition: transform 0.35s ease, filter 0.35s ease;
}
.side-tool a:hover { transform: translateY(-4px) scale(1.06); filter: brightness(1.1); }

/* ========== 返回顶部 ========== */
#backToTop {
    position: fixed;
    right: 20px;
    bottom: 70px;
    width: 54px;
    height: 54px;
    border-radius: 50%;
    background: #fff;
    color: #0096B7;
    border: 1px solid rgba(0, 180, 216, 0.35);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    z-index: 50;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.4s ease, transform 0.4s ease;
    box-shadow: 0 10px 24px -12px rgba(0, 180, 216, 0.45);
}
#backToTop.show { opacity: 1; visibility: visible; }
#backToTop:hover { transform: translateY(-4px); }

/* ========== Footer ========== */
/* 使用 Tailwind 即可，额外补 hover 色（如未定义 brandTealLight 时） */
footer a.hover\:text-brandTealLight:hover { color: #72E1F0; }

/* ========== 通用工具 ========== */
.content-auto { content-visibility: auto; }
.line-clamp-2 {
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}