:root {
        --navy: #0a1628;
        --blue: #1a3a6b;
        --accent: #2563eb;
        --accent-light: #60a5fa;
        --white: #ffffff;
        --gray-50: #f8fafc;
        --gray-100: #f1f5f9;
        --gray-200: #e2e8f0;
        --gray-400: #94a3b8;
        --gray-600: #475569;
        --gray-800: #1e293b;
        --text: #0f172a;
      }

      *,
      *::before,
      *::after {
        box-sizing: border-box;
        margin: 0;
        padding: 0;
      }
      html {
        scroll-behavior: smooth;
      }
      body {
        font-family: "Sora", sans-serif;
        color: var(--text);
        background: var(--white);
        overflow-x: hidden;
      }

      /* ── NAV ── */
      nav {
        position: fixed;
        top: 0;
        left: 0;
        right: 0;
        z-index: 100;
        display: flex;
        align-items: center;
        justify-content: space-between;
        padding: 0 3rem;
        height: 64px;
        background: rgba(10, 22, 40, 0.97);
        backdrop-filter: blur(12px);
        border-bottom: 1px solid rgba(255, 255, 255, 0.07);
      }

      .nav-logo {
        display: flex;
        align-items: center;
        gap: 0.75rem;
        text-decoration: none;
      }

      .nav-logo-icon {
        width: 36px;
        height: 36px;
        background: linear-gradient(135deg, var(--accent), var(--accent-light));
        border-radius: 8px;
        display: grid;
        place-items: center;
        font-family: "JetBrains Mono", monospace;
        font-size: 0.7rem;
        font-weight: 500;
        color: #fff;
      }

      .nav-logo span {
        font-size: 0.85rem;
        font-weight: 600;
        color: #fff;
      }

      .nav-links {
        display: flex;
        gap: 2rem;
        list-style: none;
      }

      .nav-links a {
        color: rgba(255, 255, 255, 0.7);
        text-decoration: none;
        font-size: 0.82rem;
        font-weight: 500;
        letter-spacing: 0.04em;
        transition: color 0.2s;
      }

      .nav-links a:hover {
        color: #fff;
      }
      .nav-links a.active {
        color: #fff;
        border-bottom: 2px solid var(--accent-light);
        padding-bottom: 2px;
      }

      .hamburger {
        display: none;
        flex-direction: column;
        gap: 5px;
        cursor: pointer;
        background: none;
        border: none;
      }
      .hamburger span {
        display: block;
        width: 24px;
        height: 2px;
        background: #fff;
      }

      /* ── PAGE HEADER ── */
      .page-header {
        margin-top: 64px;
        background: var(--navy);
        padding: 4rem 0 3rem;
        position: relative;
        overflow: hidden;
      }

      .page-header::before {
        content: "";
        position: absolute;
        inset: 0;
        background: radial-gradient(
          ellipse 70% 80% at 20% 50%,
          rgba(37, 99, 235, 0.2) 0%,
          transparent 70%
        );
      }

      .page-header .container {
        position: relative;
        z-index: 1;
        max-width: 1140px;
        margin: 0 auto;
        padding: 0 2rem;
      }

      .breadcrumb {
        display: flex;
        align-items: center;
        gap: 0.5rem;
        font-size: 0.75rem;
        color: rgba(255, 255, 255, 0.4);
        margin-bottom: 0.75rem;
        font-family: "JetBrains Mono", monospace;
      }

      .breadcrumb a {
        color: rgba(255, 255, 255, 0.4);
        text-decoration: none;
      }
      .breadcrumb a:hover {
        color: rgba(255, 255, 255, 0.7);
      }
      .breadcrumb span {
        color: rgba(255, 255, 255, 0.25);
      }

      .page-header h1 {
        font-family: "DM Serif Display", serif;
        font-size: clamp(2rem, 4vw, 3rem);
        color: #fff;
        margin-bottom: 0.5rem;
      }

      .page-header p {
        color: rgba(255, 255, 255, 0.5);
        font-size: 0.9rem;
        font-weight: 300;
      }

      /* ── CONTAINER ── */
      .container {
        max-width: 1140px;
        margin: 0 auto;
        padding: 0 2rem;
      }

      /* ── SECTION ── */
      .member-section {
        padding: 4rem 0 2rem;
      }

      .section-anchor {
        display: block;
        margin-top: -80px; /* offset for fixed nav */
        padding-top: 80px;
        visibility: hidden;
      }

      .section-heading {
        display: flex;
        align-items: center;
        gap: 1.25rem;
        margin-bottom: 2.5rem;
      }

      .section-heading h2 {
        font-family: "DM Serif Display", serif;
        font-size: 1.8rem;
        color: var(--navy);
        white-space: nowrap;
      }

      .section-heading::after {
        content: "";
        flex: 1;
        height: 1px;
        background: var(--gray-200);
      }

      /* ── PROFESSOR CARD ── */
      .prof-card {
        display: grid;
        grid-template-columns: 220px 1fr;
        gap: 2.5rem;
        background: var(--gray-50);
        border-radius: 20px;
        border: 1px solid var(--gray-200);
        overflow: hidden;
        padding: 2.5rem;
      }

      .prof-photo {
        width: 220px;
        height: 260px;
        object-fit: cover;
        border-radius: 14px;
        background: var(--gray-200);
        display: block;
      }

      .prof-photo-placeholder {
        width: 220px;
        height: 260px;
        border-radius: 14px;
        background: linear-gradient(135deg, #1a3a6b, #2563eb);
        display: flex;
        align-items: center;
        justify-content: center;
        font-size: 4rem;
        color: rgba(255, 255, 255, 0.5);
        flex-shrink: 0;
      }

      .prof-name {
        font-family: "DM Serif Display", serif;
        font-size: 1.6rem;
        color: var(--navy);
        margin-bottom: 0.25rem;
      }

      .prof-title {
        font-size: 0.85rem;
        color: var(--accent);
        font-weight: 500;
        margin-bottom: 1.5rem;
      }

      .prof-block {
        margin-bottom: 1.5rem;
      }

      .prof-block h4 {
        font-size: 0.72rem;
        font-weight: 700;
        color: var(--gray-400);
        letter-spacing: 0.12em;
        text-transform: uppercase;
        margin-bottom: 0.6rem;
        padding-bottom: 0.4rem;
        border-bottom: 1px solid var(--gray-200);
      }

      .prof-block ul {
        list-style: none;
      }

      .prof-block li {
        font-size: 0.83rem;
        color: var(--gray-800);
        padding: 0.25rem 0;
        padding-left: 1rem;
        position: relative;
        line-height: 1.5;
      }

      .prof-block li::before {
        content: "·";
        position: absolute;
        left: 0;
        color: var(--accent);
      }

      .prof-block li span {
        font-size: 0.75rem;
        color: var(--gray-400);
        display: block;
        padding-left: 0.5rem;
        line-height: 1.4;
      }

      /* ── MEMBER GRID ── */
      .member-grid {
        display: grid;
        grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
        gap: 1.5rem;
      }

      .member-card {
        background: #fff;
        border-radius: 16px;
        border: 1px solid var(--gray-200);
        overflow: hidden;
        transition:
          box-shadow 0.3s,
          transform 0.3s;
      }

      .member-card:hover {
        box-shadow: 0 8px 30px rgba(0, 0, 0, 0.08);
        transform: translateY(-3px);
      }

      .member-card a {
        text-decoration: none;
        display: block;
      }

      .member-photo {
        width: 100%;
        aspect-ratio: 1 / 1;
        object-fit: cover;
        background: var(--gray-100);
        display: block;
      }

      .member-photo-placeholder {
        width: 100%;
        aspect-ratio: 1 / 1;
        background: linear-gradient(135deg, var(--gray-100), var(--gray-200));
        display: flex;
        align-items: center;
        justify-content: center;
        font-size: 3rem;
        color: var(--gray-400);
      }

      .member-info {
        padding: 1rem;
      }

      .member-badge {
        display: inline-block;
        font-size: 0.62rem;
        font-weight: 700;
        letter-spacing: 0.08em;
        text-transform: uppercase;
        padding: 0.15rem 0.5rem;
        border-radius: 4px;
        margin-bottom: 0.5rem;
      }

      .badge-phd {
        background: rgba(37, 99, 235, 0.1);
        color: var(--accent);
      }
      .badge-ms-phd {
        background: rgba(139, 92, 246, 0.1);
        color: #7c3aed;
      }
      .badge-ms {
        background: rgba(16, 185, 129, 0.1);
        color: #059669;
      }
      .badge-intern {
        background: rgba(245, 158, 11, 0.1);
        color: #d97706;
      }

      .member-name {
        font-size: 0.9rem;
        font-weight: 700;
        color: var(--navy);
        line-height: 1.3;
        margin-bottom: 0.15rem;
      }

      .member-name-ko {
        font-size: 0.75rem;
        color: var(--gray-400);
        margin-bottom: 0.4rem;
      }

      .member-research {
        font-size: 0.75rem;
        color: var(--gray-600);
        line-height: 1.4;
        margin-bottom: 0.4rem;
      }

      .member-tags {
        display: flex;
        flex-wrap: wrap;
        gap: 0.25rem;
      }

      .member-tag {
        font-size: 0.62rem;
        padding: 0.12rem 0.45rem;
        border-radius: 4px;
        background: var(--gray-100);
        color: var(--gray-400);
        font-weight: 500;
      }

      .member-tag.award {
        background: rgba(245, 158, 11, 0.1);
        color: #d97706;
      }

      .member-links {
        display: flex;
        gap: 0.4rem;
        margin-top: 0.5rem;
      }

      .member-link {
        width: 26px;
        height: 26px;
        border-radius: 6px;
        border: 1px solid var(--gray-200);
        display: grid;
        place-items: center;
        font-size: 0.72rem;
        text-decoration: none;
        color: var(--gray-400);
        transition: all 0.2s;
      }

      .member-link:hover {
        border-color: var(--accent);
        color: var(--accent);
        background: rgba(37, 99, 235, 0.05);
      }

      /* ── ALUMNI ── */
      .alumni-section {
        padding: 2rem 0 4rem;
      }

      .alumni-subsection {
        margin-bottom: 2rem;
      }

      .alumni-subsection h3 {
        font-size: 0.95rem;
        font-weight: 700;
        color: var(--navy);
        margin-bottom: 1rem;
        padding-bottom: 0.5rem;
        border-bottom: 2px solid var(--gray-100);
      }

      .alumni-list {
        list-style: none;
      }

      .alumni-list li {
        display: grid;
        grid-template-columns: 240px 1fr;
        gap: 1rem;
        padding: 0.65rem 0;
        border-bottom: 1px solid var(--gray-100);
        font-size: 0.85rem;
      }

      .alumni-list li:last-child {
        border-bottom: none;
      }

      .alumni-name {
        font-weight: 600;
        color: var(--navy);
        display: flex;
        align-items: center;
        gap: 0.4rem;
      }

      .alumni-name a {
        color: var(--accent);
        font-size: 0.8rem;
        text-decoration: none;
      }

      .alumni-name a:hover {
        text-decoration: underline;
      }

      .alumni-period {
        font-family: "JetBrains Mono", monospace;
        font-size: 0.68rem;
        color: var(--gray-400);
      }

      .alumni-desc {
        color: var(--gray-600);
        font-size: 0.82rem;
        line-height: 1.5;
      }

      /* ── STICKY NAV ── */
      .member-nav {
        position: sticky;
        top: 64px;
        z-index: 50;
        background: rgba(255, 255, 255, 0.95);
        backdrop-filter: blur(8px);
        border-bottom: 1px solid var(--gray-200);
        padding: 0 2rem;
      }

      .member-nav-inner {
        max-width: 1140px;
        margin: 0 auto;
        display: flex;
        gap: 0;
      }

      .member-nav-link {
        padding: 0.9rem 1.25rem;
        font-size: 0.82rem;
        font-weight: 600;
        color: var(--gray-400);
        text-decoration: none;
        border-bottom: 2px solid transparent;
        transition: all 0.2s;
      }

      .member-nav-link:hover {
        color: var(--navy);
      }
      .member-nav-link.active {
        color: var(--accent);
        border-bottom-color: var(--accent);
      }

      /* ── FOOTER ── */
      footer {
        background: var(--navy);
        padding: 2rem;
        text-align: center;
        font-size: 0.78rem;
        color: rgba(255, 255, 255, 0.35);
      }

      /* ── MOBILE ── */
      @media (max-width: 900px) {
        nav {
          padding: 0 1.5rem;
        }
        .nav-links {
          display: none;
        }
        .nav-links.open {
          display: flex;
          flex-direction: column;
          position: fixed;
          top: 64px;
          left: 0;
          right: 0;
          background: var(--navy);
          padding: 1.5rem 2rem;
          border-top: 1px solid rgba(255, 255, 255, 0.08);
          gap: 1.25rem;
        }
        .hamburger {
          display: flex;
        }
        .prof-card {
          grid-template-columns: 1fr;
        }
        .prof-photo-placeholder {
          width: 100%;
          height: 220px;
        }
        .member-grid {
          grid-template-columns: repeat(2, 1fr);
        }
        .alumni-list li {
          grid-template-columns: 1fr;
          gap: 0.3rem;
        }
        .member-nav-inner {
          overflow-x: auto;
        }
      }

      @media (max-width: 500px) {
        .member-grid {
          grid-template-columns: repeat(2, 1fr);
        }
      }