/* ===== Reset & Variables ===== */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }

:root {
    --white: #FBFBFD;
    --black: #1D1D1F;
    --dark: #000000;
    --gray-50: #F5F5F7;
    --gray-100: #E8E8ED;
    --gray-200: #D2D2D7;
    --gray-400: #86868B;
    --gray-600: #6E6E73;
    --gray-800: #424245;
    --gray-900: #1D1D1F;
    --font-cn: 'Noto Sans SC', 'PingFang SC', -apple-system, sans-serif;
    --font-en: 'Inter', 'SF Pro Display', -apple-system, sans-serif;
    --ease: cubic-bezier(0.25, 0.46, 0.45, 0.94);
    --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
}

html { scroll-behavior: smooth; font-size: 16px; }
body {
    font-family: var(--font-cn);
    color: var(--gray-900);
    background: var(--white);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
}

a { text-decoration: none; color: inherit; }
img { max-width: 100%; height: auto; display: block; }

/* ===== Container ===== */
.container { max-width: 1080px; margin: 0 auto; padding: 0 24px; }
.container-wide { max-width: 1400px; margin: 0 auto; padding: 0 24px; }

/* ===== Navigation (Apple-style glass) ===== */
.nav {
    position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
    background: rgba(29,29,31,0.8);
    backdrop-filter: saturate(180%) blur(20px);
    -webkit-backdrop-filter: saturate(180%) blur(20px);
    border-bottom: 1px solid rgba(255,255,255,0.08);
    transition: background 0.4s;
}
.nav.scrolled { background: rgba(29,29,31,0.95); }

.nav-inner {
    max-width: 1080px; margin: 0 auto; padding: 0 24px;
    display: flex; align-items: center; justify-content: space-between;
    height: 52px;
}

.nav-logo {
    font-size: 18px; font-weight: 600; color: var(--white);
    font-family: var(--font-en); letter-spacing: -0.3px;
}

.nav-links { display: flex; gap: 24px; align-items: center; }
.nav-links a {
    font-size: 13px; color: rgba(255,255,255,0.72);
    transition: color 0.2s; font-weight: 400;
    font-family: var(--font-en);
}
.nav-links a:hover { color: var(--white); }
.nav-links a.active { color: var(--white); }

.nav-cta {
    background: #2997ff !important; color: var(--white) !important;
    padding: 6px 18px; border-radius: 980px; font-size: 12px !important;
    font-weight: 500; transition: all 0.2s;
}
.nav-cta:hover { background: #0077ed !important; }

.nav-toggle {
    display: none; background: none; border: none; cursor: pointer;
    width: 20px; height: 14px; position: relative;
}
.nav-toggle span {
    display: block; width: 100%; height: 1.5px;
    background: var(--white); position: absolute; left: 0;
    transition: all 0.3s;
}
.nav-toggle span:nth-child(1) { top: 0; }
.nav-toggle span:nth-child(2) { top: 6px; }
.nav-toggle span:nth-child(3) { top: 12px; }
.nav-toggle.active span:nth-child(1) { top: 6px; transform: rotate(45deg); }
.nav-toggle.active span:nth-child(2) { opacity: 0; }
.nav-toggle.active span:nth-child(3) { top: 6px; transform: rotate(-45deg); }

.mobile-menu {
    display: none; position: fixed; top: 52px; left: 0; right: 0;
    background: rgba(29,29,31,0.97); backdrop-filter: blur(20px);
    z-index: 999; padding: 20px 24px;
    border-bottom: 1px solid rgba(255,255,255,0.08);
}
.mobile-menu.active { display: flex; flex-direction: column; gap: 12px; }
.mobile-menu a {
    font-size: 16px; color: rgba(255,255,255,0.72); padding: 8px 0;
    font-family: var(--font-en);
}

/* ===== Hero Combined (Hero + Personal Card merged) ===== */
.hero-combined {
    min-height: 100vh; display: flex; align-items: center;
    background: var(--dark); padding: 100px 24px 80px;
    position: relative; overflow: hidden;
}
.hero-combined::before {
    content: ''; position: absolute; inset: 0;
    background: radial-gradient(ellipse at 30% 40%, rgba(41,151,255,0.05) 0%, transparent 60%);
}

.hero-combined-inner {
    max-width: 1080px; margin: 0 auto; width: 100%;
    display: grid; grid-template-columns: 1fr 320px; gap: 80px;
    align-items: center; position: relative; z-index: 1;
}

.hero-info {}

.hero-name {
    font-size: clamp(48px, 8vw, 72px); font-weight: 700;
    letter-spacing: -2px; line-height: 1; margin-bottom: 8px;
    color: var(--white);
}

.hero-edu {
    font-size: 18px; color: rgba(255,255,255,0.45);
    margin-bottom: 28px;
}

.hero-bio {
    font-size: 17px; color: rgba(255,255,255,0.65);
    line-height: 1.8; margin-bottom: 32px; max-width: 520px;
}

.hero-stats {
    display: flex; gap: 12px; margin-bottom: 28px; padding-bottom: 28px;
    border-bottom: 1px solid rgba(255,255,255,0.08);
}
.hero-stat {
    display: flex; flex-direction: column; align-items: center;
    background: rgba(255,255,255,0.08);
    border-radius: 10px;
    padding: 12px 18px;
    transition: all 0.3s;
    min-width: 100px;
}
.hero-stat:hover {
    background: rgba(255,255,255,0.15);
}
.hero-stat-value {
    font-size: 22px; font-weight: 700; color: var(--white);
    font-family: var(--font-en); letter-spacing: -0.5px;
    white-space: nowrap; line-height: 1.2;
}
.hero-stat-value--big {
    font-size: 28px;
}
.hero-stat-label {
    font-size: 12px; color: rgba(255,255,255,0.45);
    margin-top: 3px;
    white-space: nowrap;
}

.hero-tags {
    display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 36px;
}
.hero-tags .tag {
    padding: 6px 16px; border-radius: 980px; font-size: 13px;
    background: rgba(255,255,255,0.06); color: rgba(255,255,255,0.7);
    font-weight: 500; border: 1px solid rgba(255,255,255,0.08);
}

.hero-cta {
    display: inline-block; background: #2997ff; color: var(--white);
    padding: 14px 32px; border-radius: 980px; font-size: 15px;
    font-weight: 500; transition: all 0.3s;
}
.hero-cta:hover { background: #0077ed; transform: translateY(-1px); }

.hero-photo-wrap {}
.hero-photo {
    width: 320px; height: auto; max-height: 420px;
    object-fit: contain; border-radius: 24px;
    box-shadow: 0 24px 80px rgba(0,0,0,0.3);
}

/* ===== Personal Card (Homepage) ===== */
.personal-card-section {
    padding: 120px 0;
    background: var(--white);
}

.personal-card {
    display: grid; grid-template-columns: 280px 1fr; gap: 60px;
    align-items: start; max-width: 900px; margin: 0 auto;
}

.personal-card-photo {
    width: 280px; height: 350px; object-fit: cover;
    border-radius: 20px; box-shadow: 0 20px 60px rgba(0,0,0,0.1);
}

.personal-card-info h2 {
    font-size: 36px; font-weight: 700; letter-spacing: -1px;
    margin-bottom: 4px; font-family: var(--font-en);
}

.personal-card-info .subtitle {
    font-size: 16px; color: var(--gray-400); margin-bottom: 28px;
    font-family: var(--font-en);
}

.personal-card-stats {
    display: grid; grid-template-columns: repeat(3, 1fr);
    gap: 24px; margin-bottom: 28px; padding-bottom: 28px;
    border-bottom: 1px solid var(--gray-100);
}

.stat-item { text-align: center; }
.stat-item .stat-value {
    font-size: 28px; font-weight: 700; color: var(--gray-900);
    font-family: var(--font-en); letter-spacing: -1px;
}
.stat-item .stat-label {
    font-size: 12px; color: var(--gray-400); margin-top: 2px;
    font-family: var(--font-en); text-transform: uppercase; letter-spacing: 0.5px;
}

.personal-card-bio {
    font-size: 16px; color: var(--gray-600); line-height: 1.8;
    margin-bottom: 24px;
}

.personal-card-tags {
    display: flex; flex-wrap: wrap; gap: 8px;
}
.personal-card-tags .tag {
    padding: 6px 16px; border-radius: 980px; font-size: 13px;
    background: var(--gray-50); color: var(--gray-800);
    font-weight: 500; border: 1px solid var(--gray-100);
}

/* ===== Career Timeline (Apple-style section) ===== */
.career-section {
    padding: 140px 0;
    background: var(--dark);
    color: var(--white);
}

.career-section .section-label {
    text-align: center; font-size: 14px; font-weight: 500;
    letter-spacing: 2px; text-transform: uppercase;
    color: #2997ff; font-family: var(--font-en); margin-bottom: 12px;
}

.career-section .section-title {
    text-align: center; font-size: clamp(36px, 6vw, 56px);
    font-weight: 700; letter-spacing: -2px; margin-bottom: 16px;
    font-family: var(--font-en); color: var(--white);
}

.career-section .section-subtitle {
    text-align: center; font-size: 19px; color: rgba(255,255,255,0.5);
    max-width: 600px; margin: 0 auto 80px; line-height: 1.6;
}

.career-steps {
    display: grid; grid-template-columns: repeat(4, 1fr);
    gap: 2px; max-width: 960px; margin: 0 auto;
}

.career-step {
    background: rgba(255,255,255,0.04);
    padding: 40px 28px; text-align: center;
    transition: all 0.4s; border-radius: 1px;
}
.career-step:hover { background: rgba(255,255,255,0.08); }

.career-step-num {
    font-size: 48px; font-weight: 200; color: #2997ff;
    font-family: var(--font-en); margin-bottom: 16px; line-height: 1;
}

.career-step-label {
    font-size: 13px; font-weight: 600; text-transform: uppercase;
    letter-spacing: 1.5px; color: rgba(255,255,255,0.4);
    font-family: var(--font-en); margin-bottom: 8px;
}

.career-step h3 {
    font-size: 18px; font-weight: 600; color: var(--white);
    margin-bottom: 4px; letter-spacing: -0.3px;
}

.career-step .company {
    font-size: 14px; color: rgba(255,255,255,0.45);
    font-family: var(--font-en); margin-bottom: 12px;
}

.career-step p {
    font-size: 13px; color: rgba(255,255,255,0.55);
    line-height: 1.6;
}

/* ===== Portfolio Cards (Apple product card style) ===== */
.portfolio-section { padding: 140px 0; background: var(--white); }

.section-label-light {
    text-align: center; font-size: 14px; font-weight: 500;
    letter-spacing: 2px; text-transform: uppercase;
    color: #2997ff; font-family: var(--font-en); margin-bottom: 12px;
}

.section-title-light {
    text-align: center; font-size: clamp(36px, 6vw, 56px);
    font-weight: 700; letter-spacing: -2px; margin-bottom: 16px;
    font-family: var(--font-en); color: var(--gray-900);
}

.section-subtitle-light {
    text-align: center; font-size: 19px; color: var(--gray-400);
    max-width: 600px; margin: 0 auto 80px; line-height: 1.6;
}

.portfolio-grid {
    display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px;
    max-width: 960px; margin: 0 auto;
}

.portfolio-card {
    background: var(--gray-50); border-radius: 20px;
    overflow: hidden; transition: all 0.5s var(--ease-out);
    display: block; position: relative;
}
.portfolio-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 20px 60px rgba(0,0,0,0.06);
}

.portfolio-card-visual {
    height: 240px; display: flex; align-items: center; justify-content: center;
    font-size: 64px; background: var(--gray-50);
    overflow: hidden;
}
.portfolio-card-visual img {
    width: 100%; height: 100%; object-fit: cover;
    transition: transform 0.5s var(--ease-out);
}
.portfolio-card:hover .portfolio-card-visual img {
    transform: scale(1.03);
}

.portfolio-card-body { padding: 28px; }
.portfolio-card-body h3 {
    font-size: 22px; font-weight: 600; margin-bottom: 8px;
    letter-spacing: -0.3px; color: var(--gray-900);
}
.portfolio-card-body p {
    font-size: 14px; color: var(--gray-600); line-height: 1.7;
    margin-bottom: 12px;
}
.portfolio-card-body .tags {
    display: flex; flex-wrap: wrap; gap: 6px;
}
.portfolio-card-body .tag {
    font-size: 11px; padding: 3px 12px; border-radius: 980px;
    background: var(--white); color: var(--gray-600);
    font-weight: 500; font-family: var(--font-en);
    border: 1px solid var(--gray-100);
}

/* ===== Full-width Feature Card ===== */
.feature-card {
    max-width: 960px; margin: 0 auto 20px;
    background: var(--gray-50); border-radius: 24px;
    overflow: hidden; display: grid; grid-template-columns: 1fr 1fr;
    transition: all 0.5s var(--ease-out); cursor: pointer;
}
.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 20px 60px rgba(0,0,0,0.06);
}

.feature-card-visual {
    min-height: 360px; overflow: hidden;
}
.feature-card-visual img {
    width: 100%; height: 100%; object-fit: cover;
    transition: transform 0.5s var(--ease-out);
}
.feature-card:hover .feature-card-visual img {
    transform: scale(1.03);
}

.feature-card-body {
    padding: 48px 40px; display: flex; flex-direction: column;
    justify-content: center;
}
.feature-card-body h3 {
    font-size: 28px; font-weight: 700; margin-bottom: 12px;
    letter-spacing: -0.5px;
}
.feature-card-body p {
    font-size: 15px; color: var(--gray-600); line-height: 1.8;
    margin-bottom: 16px;
}

/* ===== Activities Section (Research Council) ===== */
.activities-section { padding: 140px 0; background: var(--dark); color: var(--white); }

.activity-grid {
    display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px;
    max-width: 960px; margin: 0 auto;
}

.activity-card {
    border-radius: 16px; overflow: hidden; position: relative;
    cursor: pointer; transition: all 0.4s var(--ease-out);
}
.activity-card:hover { transform: translateY(-4px); }

.activity-card img {
    width: 100%; height: 220px; object-fit: cover;
    transition: transform 0.5s var(--ease-out);
}
.activity-card:hover img { transform: scale(1.05); }

.activity-card-overlay {
    position: absolute; bottom: 0; left: 0; right: 0;
    padding: 20px;
    background: linear-gradient(transparent, rgba(0,0,0,0.7));
}
.activity-card-overlay h4 {
    font-size: 18px; font-weight: 600; color: var(--white);
    margin-bottom: 2px;
}
.activity-card-overlay p {
    font-size: 12px; color: rgba(255,255,255,0.6);
}

/* ===== Hobbies ===== */
.hobbies-section { padding: 100px 0; background: var(--white); }

.hobbies-grid {
    display: flex; justify-content: center; gap: 32px;
    max-width: 800px; margin: 0 auto;
}
.hobby-item { text-align: center; flex: 1; }
.hobby-item img {
    width: 100%; max-width: 160px; height: 140px; object-fit: cover;
    border-radius: 16px; margin: 0 auto 10px; display: block;
}
.hobby-item span {
    font-size: 14px; color: var(--gray-600);
}

/* ===== Footer ===== */
.footer {
    padding: 40px 0; text-align: center;
    border-top: 1px solid var(--gray-100);
    font-size: 13px; color: var(--gray-400);
    font-family: var(--font-en);
}

/* ===== Modal ===== */
.modal-overlay {
    position: fixed; inset: 0; background: rgba(0,0,0,0.5);
    z-index: 2000; display: none; align-items: center; justify-content: center;
    padding: 24px; backdrop-filter: blur(12px);
}
.modal-overlay.active { display: flex; }

.modal {
    background: var(--white); border-radius: 20px;
    max-width: 900px; width: 100%; max-height: 90vh;
    overflow-y: auto; animation: modalIn 0.3s var(--ease-out);
}

.modal-close {
    position: sticky; top: 16px; float: right; margin: 16px;
    width: 32px; height: 32px; border-radius: 50%;
    background: var(--gray-50); border: none; cursor: pointer;
    font-size: 16px; display: flex; align-items: center; justify-content: center;
    z-index: 10; transition: background 0.2s; color: var(--gray-600);
}
.modal-close:hover { background: var(--gray-100); }

.modal-body { padding: 40px; }
.modal-body h2 {
    font-size: 28px; font-weight: 700; margin-bottom: 16px;
    letter-spacing: -0.5px;
}
.modal-body p {
    font-size: 16px; color: var(--gray-600); line-height: 1.8;
    margin-bottom: 16px;
}
.modal-body video {
    width: 100%; border-radius: 12px; margin: 16px 0;
}

.modal-body video.portrait-video {
    display: block;
    width: auto;
    height: auto;
    max-width: min(100%, 360px);
    max-height: 65vh;
    margin: 16px auto;
    object-fit: contain;
    background: #000;
}

.modal-gallery {
    display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 12px; margin-top: 20px;
}
.modal-gallery img {
    width: 100%; height: 160px; object-fit: cover;
    border-radius: 10px; cursor: pointer;
    transition: transform 0.2s;
}
.modal-gallery img:hover { transform: scale(1.02); }

/* ===== Page Header (Sub-pages) ===== */
.page-header {
    padding: 140px 0 60px; text-align: center;
    background: var(--dark); color: var(--white);
}
.page-header h1 {
    font-size: clamp(36px, 6vw, 56px); font-weight: 700;
    letter-spacing: -2px; margin-bottom: 16px;
    font-family: var(--font-en); color: var(--white);
}
.page-header p {
    font-size: 18px; color: rgba(255,255,255,0.5);
    max-width: 600px; margin: 0 auto; line-height: 1.7;
}

.page-section { padding: 100px 0; }
.page-section:nth-child(even) { background: var(--gray-50); }

.page-section-title {
    font-size: 28px; font-weight: 700; letter-spacing: -0.5px;
    color: var(--gray-900); margin-bottom: 40px;
}

/* ===== Work Cards (Sub-pages) ===== */
.work-grid {
    display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 20px;
}

.work-card {
    background: var(--white); border-radius: 16px;
    overflow: hidden; cursor: pointer;
    transition: all 0.4s var(--ease-out);
    border: 1px solid var(--gray-100);
}
.work-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 40px rgba(0,0,0,0.06);
}

.work-card-image {
    width: 100%; height: 200px; object-fit: cover;
    background: var(--gray-50);
}

.work-card-body { padding: 24px; }
.work-card-title {
    font-size: 18px; font-weight: 600; margin-bottom: 8px;
    letter-spacing: -0.3px;
}
.work-card-desc {
    font-size: 14px; color: var(--gray-600); line-height: 1.6;
}

/* ===== Gallery ===== */
.gallery-grid {
    display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
    gap: 14px;
}
.gallery-item {
    border-radius: 12px; overflow: hidden; cursor: pointer;
    transition: transform 0.3s;
}
.gallery-item:hover { transform: scale(1.02); }
.gallery-item img { width: 100%; height: 180px; object-fit: cover; }

/* ===== Tags ===== */
.tags { display: flex; flex-wrap: wrap; gap: 6px; margin: 10px 0; }
.tag {
    display: inline-block; padding: 3px 12px; border-radius: 980px;
    font-size: 11px; font-weight: 500;
    background: var(--gray-50); color: var(--gray-600);
    font-family: var(--font-en); border: 1px solid var(--gray-100);
}

/* ===== Section Nav Cards (Homepage big cards) ===== */
.section-nav-grid {
    display: flex; gap: 0; max-width: 1000px; margin: 0 auto;
}

.section-nav-card {
    display: block; flex: 1;
    transition: all 0.3s var(--ease-out);
    background: var(--gray-50); position: relative;
    text-align: center; padding: 28px 16px;
    border-right: 1px solid var(--gray-100);
}
.section-nav-card:last-child { border-right: none; }
.section-nav-card:hover {
    background: var(--dark);
}
.section-nav-card:hover h3,
.section-nav-card:hover p,
.section-nav-card:hover .section-nav-arrow {
    color: var(--white);
}

.section-nav-card h3 {
    font-size: 18px; font-weight: 600; margin-bottom: 6px;
    letter-spacing: -0.3px; color: var(--gray-900);
    transition: color 0.3s;
}

.section-nav-card p {
    font-size: 13px; color: var(--gray-500); margin-bottom: 0;
    transition: color 0.3s;
}

.section-nav-arrow {
    font-size: 18px; color: var(--gray-400);
    transition: all 0.3s; display: block; margin-top: 8px;
}
.section-nav-card:hover .section-nav-arrow {
    color: var(--white); transform: translateX(4px);
}

/* ===== Section Nav Section (Homepage) ===== */
.section-nav-section {
    padding: 80px 0 100px;
    background: var(--white);
}

/* ===== Animations ===== */
@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(40px); }
    to { opacity: 1; transform: translateY(0); }
}
@keyframes modalIn {
    from { opacity: 0; transform: scale(0.96); }
    to { opacity: 1; transform: scale(1); }
}

.fade-in {
    opacity: 0; transform: translateY(40px);
    transition: all 0.8s var(--ease-out);
}
.fade-in.visible { opacity: 1; transform: translateY(0); }

/* ===== Responsive ===== */
@media (max-width: 768px) {
    .nav-links { display: none; }
    .nav-toggle { display: block; }
    .hero-combined-inner { grid-template-columns: 1fr; gap: 40px; text-align: center; }
    .hero-bio { max-width: 100%; }
    .hero-stats { justify-content: center; flex-wrap: wrap; gap: 20px; }
    .hero-tags { justify-content: center; }
    .hero-photo-wrap { display: flex; justify-content: center; }
    .hero-photo { width: 240px; height: 300px; }
    .personal-card { grid-template-columns: 1fr; gap: 32px; text-align: center; }
    .personal-card-photo { width: 200px; height: 250px; margin: 0 auto; }
    .personal-card-stats { grid-template-columns: repeat(3, 1fr); }
    .career-steps { grid-template-columns: repeat(2, 1fr); }
    .portfolio-grid { grid-template-columns: 1fr; }
    .section-nav-grid { grid-template-columns: 1fr; }
    .feature-card { grid-template-columns: 1fr; }
    .feature-card-visual { min-height: 240px; }
    .activity-grid { grid-template-columns: repeat(2, 1fr); }
    .work-grid { grid-template-columns: 1fr; }
}

@media (max-width: 480px) {
    .hero-name { font-size: 48px; }
    .career-steps { grid-template-columns: 1fr; }
    .activity-grid { grid-template-columns: 1fr; }
    .personal-card-stats { grid-template-columns: 1fr; gap: 16px; }
}

/* ===== Lightbox ===== */
.lightbox {
    position: fixed; inset: 0; z-index: 3000;
    background: rgba(0,0,0,0.95);
    display: none; align-items: center; justify-content: center;
    padding: 60px;
    cursor: pointer;
}
.lightbox.active { display: flex; }
.lightbox-img {
    max-width: 85vw; max-height: 85vh; object-fit: contain;
    border-radius: 8px; cursor: default;
    user-select: none;
}
.lightbox-nav {
    position: absolute; bottom: 40px; left: 50%; transform: translateX(-50%);
    display: flex; align-items: center; gap: 32px;
    cursor: default;
}
.lightbox-prev, .lightbox-next {
    background: rgba(255,255,255,0.12); border: none; color: white;
    width: 52px; height: 52px; border-radius: 50%; font-size: 32px;
    cursor: pointer; display: flex; align-items: center; justify-content: center;
    transition: all 0.2s; line-height: 1;
}
.lightbox-prev:hover, .lightbox-next:hover {
    background: rgba(255,255,255,0.25);
}
.lightbox-counter {
    color: rgba(255,255,255,0.5); font-size: 15px;
    font-family: var(--font-en); min-width: 60px; text-align: center;
}