/* ===== GLOBAL ===== */
* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: Arial, sans-serif;
    color: #3E3A35;
    overflow-x: hidden;
    background: #fff;
}

/* ================= UNIVERSAL SUBPAGE HERO ================= */
.sub-hero {
    position: relative;
    height: var(--hero-h, 50vh);
    min-height: 280px;

    background: url("../fluorescence.jpg") center/cover no-repeat;

    display: flex;
    justify-content: center;
    align-items: center;

    overflow: hidden;
    transition: height 0.15s linear;
}

/* ================= 高级渐变遮罩（重点） ================= */
.sub-hero::before {
    content: "";
    position: absolute;
    inset: 0;

    /* ⭐中心清晰 + 边缘渐暗 */
    background: radial-gradient(
        circle at center,
        rgba(240,242,245,0.01) 0%,
        rgba(240,242,245,0.05) 70%,
        rgba(240,242,245,0.10) 100%
    );

    z-index: 1;
}

/* ================= 再加一层“边缘暗角（更高级）” ================= */
.sub-hero::after {
    content: "";
    position: absolute;
    inset: 0;

    background: radial-gradient(
        ellipse at center,
        rgba(0,0,0,0.00) 80%,
        rgba(0,0,0,0.20) 100%
    );

    z-index: 2;
}

/* ================= 文字层 ================= */
.sub-hero-text {
    position: relative;
    z-index: 3;
    text-align: center;
}

.sub-hero-text h1 {
    color: #3E3A35;
    font-size: 42px;
    font-weight: 700;
}

.sub-hero-text p {
    color: #6B5E4A;
    font-size: 18px;
}
/* ================= NAVBAR ================= */
.navbar {
    position: fixed;
    top: 25px;
    right: 40px;
    z-index: 1100;
}

.nav-right {
    display: flex;
    gap: 24px;
}

.nav-right a {
    text-decoration: none;
    color: #F8F8FF;
    font-size: 16px;
    font-weight: 600;
    display: inline-block;
    transition: color 0.25s ease, transform 0.25s ease;
}
/*正文的时候bar转黑字*/
.navbar.scrolled .nav-right a {
    color: #3E3A35;
}
.navbar.scrolled .nav-right a.active {
    color: #B85C1A;
}
.top-glass-bar.scrolled {
    background: rgba(255,255,255,0.75);
    backdrop-filter: blur(12px);
}

.nav-right a:hover {
    color: #B85C1A;
    transform: scale(1.08);
}

.nav-right a.active {
    color: #B85C1A;
    font-weight: 700;
}

.navbar,
.nav-right {
    z-index: 1100;
}

.top-glass-bar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 60px;
    background: rgba(255,255,255,0.03);
    backdrop-filter: blur(1px);
    -webkit-backdrop-filter: blur(1px);
    border-bottom: 1px solid rgba(255,255,255,0.05);
    z-index: 1000;
    pointer-events: none;
}
/* ================= CENTER TEXT ================= */
.sub-hero-text {
    position: relative;
    z-index: 3;
    text-align: center;
}

.sub-hero-text h1 {
    font-size: 42px;
    font-weight: 700;
    color: #F8F8FF;
    margin: 0 0 10px;
}

.sub-hero-text p {
    font-size: 18px;
    color: #F8F8FF;
    margin: 0;
}

/* ===== CONTENT ===== */
.research-container {
    max-width: 900px;
    margin: 0 auto;
    padding: 70px 20px;
}

.research-container h2 {
    font-size: 36px;
    margin-bottom: 40px;
    text-transform: uppercase;
}

.research-container p {
    font-size: 18px;
    margin-bottom: 30px;
    color: #444;
    line-height: 1.8;
    text-align: justify;
}

.research-container strong {
    color: #111;
}

/* =========================== top left logo =========================== */
.wu-logo {
    position: fixed;
    top: 3px;
    left: 28px;
    z-index: 1200;
}

.wu-logo img {
    height: 60px;
    width: auto;
    display: block;
}