/* ========================================
   PSB AI Lab - Main Stylesheet
   ======================================== */

/* ---- CSS Variables ---- */
:root {
    --primary: #1a56db;
    --primary-light: #3b82f6;
    --primary-dark: #1e3a8a;
    --primary-50: #eff6ff;
    --primary-100: #dbeafe;
    --primary-200: #bfdbfe;
    --accent: #06b6d4;
    --accent-light: #22d3ee;
    --dark: #0f172a;
    --dark-800: #1e293b;
    --dark-700: #334155;
    --dark-600: #475569;
    --gray-500: #64748b;
    --gray-400: #94a3b8;
    --gray-300: #cbd5e1;
    --gray-200: #e2e8f0;
    --gray-100: #f1f5f9;
    --gray-50: #f8fafc;
    --white: #ffffff;
    --success: #10b981;
    --warning: #f59e0b;
    --gradient-1: linear-gradient(135deg, #1a56db 0%, #06b6d4 100%);
    --gradient-2: linear-gradient(135deg, #0f172a 0%, #1e3a8a 100%);
    --gradient-3: linear-gradient(135deg, #eff6ff 0%, #e0f2fe 100%);
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.08);
    --shadow-md: 0 4px 20px rgba(0,0,0,0.08);
    --shadow-lg: 0 10px 40px rgba(0,0,0,0.1);
    --shadow-xl: 0 20px 60px rgba(0,0,0,0.12);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --font-main: 'Inter', 'Noto Sans KR', -apple-system, BlinkMacSystemFont, sans-serif;
}

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

html {
    scroll-behavior: smooth;
    scroll-padding-top: 80px;
}

body {
    font-family: var(--font-main);
    color: var(--dark);
    background: var(--white);
    line-height: 1.7;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
}

a {
    text-decoration: none;
    color: inherit;
    transition: var(--transition);
}

ul {
    list-style: none;
}

img {
    max-width: 100%;
    display: block;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ---- Section ---- */
.section {
    padding: 100px 0;
}

.section-header {
    text-align: center;
    margin-bottom: 64px;
}

.section-tag {
    display: inline-block;
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 3px;
    color: var(--primary);
    background: var(--primary-50);
    padding: 6px 18px;
    border-radius: 50px;
    margin-bottom: 16px;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 800;
    color: var(--dark);
    margin-bottom: 12px;
    letter-spacing: -0.02em;
}

.section-subtitle {
    font-size: 1.1rem;
    color: var(--gray-500);
    max-width: 600px;
    margin: 0 auto;
}

/* ---- Buttons ---- */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 28px;
    border-radius: var(--radius-md);
    font-size: 0.95rem;
    font-weight: 600;
    border: 2px solid transparent;
    cursor: pointer;
    transition: var(--transition);
    font-family: var(--font-main);
}

.btn-primary {
    background: var(--gradient-1);
    color: var(--white);
    border-color: transparent;
    box-shadow: 0 4px 15px rgba(26, 86, 219, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(26, 86, 219, 0.4);
}

.btn-outline {
    background: transparent;
    color: var(--white);
    border-color: rgba(255,255,255,0.4);
}

.btn-outline:hover {
    background: rgba(255,255,255,0.1);
    border-color: var(--white);
    transform: translateY(-2px);
}

.btn-sm {
    padding: 10px 20px;
    font-size: 0.875rem;
}

/* ========================================
   NAVBAR
   ======================================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: transparent;
    transition: var(--transition);
    padding: 16px 0;
}

.navbar.scrolled {
    background: rgba(255,255,255,0.95);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    box-shadow: var(--shadow-sm);
    padding: 8px 0;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
    font-size: 1.2rem;
    color: var(--white);
    z-index: 1001;
}

.navbar.scrolled .nav-logo {
    color: var(--dark);
}

.logo-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 38px;
    height: 38px;
    border-radius: var(--radius-sm);
    background: var(--gradient-1);
    color: var(--white);
    font-size: 1rem;
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 4px;
}

.nav-link {
    padding: 8px 16px;
    font-size: 0.875rem;
    font-weight: 500;
    color: rgba(255,255,255,0.8);
    border-radius: var(--radius-sm);
    position: relative;
}

.nav-link:hover,
.nav-link.active {
    color: var(--white);
    background: rgba(255,255,255,0.1);
}

.navbar.scrolled .nav-link {
    color: var(--gray-500);
}

.navbar.scrolled .nav-link:hover,
.navbar.scrolled .nav-link.active {
    color: var(--primary);
    background: var(--primary-50);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
    z-index: 1001;
}

.nav-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--white);
    border-radius: 2px;
    transition: var(--transition);
}

.navbar.scrolled .nav-toggle span {
    background: var(--dark);
}

/* ========================================
   HERO
   ======================================== */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    inset: 0;
    background: var(--gradient-2);
}

.hero-particles {
    position: absolute;
    inset: 0;
    overflow: hidden;
}

.hero-gradient {
    position: absolute;
    inset: 0;
    background: 
        radial-gradient(ellipse at 20% 50%, rgba(6, 182, 212, 0.15) 0%, transparent 60%),
        radial-gradient(ellipse at 80% 20%, rgba(59, 130, 246, 0.15) 0%, transparent 60%),
        radial-gradient(ellipse at 50% 80%, rgba(26, 86, 219, 0.1) 0%, transparent 60%);
}

.hero-content {
    position: relative;
    z-index: 10;
    text-align: center;
    color: var(--white);
    padding: 120px 24px 60px;
    max-width: 900px;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 20px;
    background: rgba(255,255,255,0.1);
    border: 1px solid rgba(255,255,255,0.15);
    border-radius: 50px;
    font-size: 0.85rem;
    font-weight: 500;
    color: rgba(255,255,255,0.9);
    backdrop-filter: blur(10px);
    margin-bottom: 32px;
}

.hero-title-main {
    display: block;
    font-size: 4.5rem;
    font-weight: 800;
    letter-spacing: -0.03em;
    line-height: 1.1;
    background: linear-gradient(135deg, #ffffff 0%, #93c5fd 50%, #22d3ee 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 8px;
}

.hero-title-sub {
    display: block;
    font-size: 1.15rem;
    font-weight: 400;
    color: rgba(255,255,255,0.6);
    letter-spacing: 2px;
}

.hero-description {
    font-size: 1.2rem;
    line-height: 1.8;
    color: rgba(255,255,255,0.75);
    margin: 28px 0 40px;
}

.hero-actions {
    display: flex;
    justify-content: center;
    gap: 16px;
    flex-wrap: wrap;
    margin-bottom: 60px;
}

.hero-stats {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 32px;
    padding: 32px 48px;
    background: rgba(255,255,255,0.05);
    border: 1px solid rgba(255,255,255,0.1);
    border-radius: var(--radius-xl);
    backdrop-filter: blur(10px);
}

.stat-item {
    text-align: center;
}

.stat-number {
    display: block;
    font-size: 2.5rem;
    font-weight: 800;
    color: var(--white);
    line-height: 1;
}

.stat-label {
    display: block;
    font-size: 0.8rem;
    color: rgba(255,255,255,0.6);
    margin-top: 6px;
    font-weight: 500;
}

.stat-divider {
    width: 1px;
    height: 40px;
    background: rgba(255,255,255,0.15);
}

/* Scroll Indicator */
.scroll-indicator {
    position: absolute;
    bottom: 32px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 10;
    animation: float 3s ease-in-out infinite;
}

.mouse {
    width: 26px;
    height: 40px;
    border: 2px solid rgba(255,255,255,0.4);
    border-radius: 13px;
    display: flex;
    justify-content: center;
    padding-top: 8px;
}

.wheel {
    width: 3px;
    height: 8px;
    background: rgba(255,255,255,0.6);
    border-radius: 3px;
    animation: scroll-wheel 2s ease-in-out infinite;
}

@keyframes scroll-wheel {
    0%, 100% { opacity: 1; transform: translateY(0); }
    50% { opacity: 0.3; transform: translateY(8px); }
}

@keyframes float {
    0%, 100% { transform: translateX(-50%) translateY(0); }
    50% { transform: translateX(-50%) translateY(-8px); }
}

/* ========================================
   ABOUT
   ======================================== */
.about {
    background: var(--gray-50);
}

.about-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
}

.about-card {
    background: var(--white);
    border-radius: var(--radius-lg);
    padding: 40px;
    border: 1px solid var(--gray-200);
    transition: var(--transition);
}

.about-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-200);
}

.about-main {
    grid-column: 1 / -1;
}

.about-card-icon {
    width: 56px;
    height: 56px;
    border-radius: var(--radius-md);
    background: var(--gradient-1);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--white);
    font-size: 1.3rem;
    margin-bottom: 20px;
}

.about-card h3 {
    font-size: 1.3rem;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--dark);
}

.about-card p {
    color: var(--gray-500);
    line-height: 1.8;
    font-size: 0.95rem;
}

/* ========================================
   PI SECTION
   ======================================== */
.pi-section {
    background: var(--white);
}

.pi-card {
    background: var(--white);
    border-radius: var(--radius-xl);
    border: 1px solid var(--gray-200);
    overflow: hidden;
    box-shadow: var(--shadow-md);
}

.pi-info {
    display: flex;
    align-items: center;
    gap: 24px;
    padding: 40px;
    background: var(--gradient-2);
    color: var(--white);
}

.pi-avatar {
    width: 100px;
    height: 100px;
    border-radius: 50%;
    background: rgba(255,255,255,0.15);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2.5rem;
    flex-shrink: 0;
    border: 3px solid rgba(255,255,255,0.2);
}

.pi-avatar-photo {
    overflow: hidden;
    padding: 0;
}

.pi-avatar-photo img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center top;
}

.pi-details h3 {
    font-size: 1.8rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.pi-name-en {
    font-size: 1rem;
    font-weight: 400;
    opacity: 0.7;
    margin-left: 8px;
}

.pi-title {
    font-size: 0.9rem;
    opacity: 0.85;
    line-height: 1.7;
}

.pi-title i {
    margin-right: 6px;
    opacity: 0.7;
}

.pi-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 32px;
    padding: 40px;
}

.pi-section-block h4 {
    font-size: 1rem;
    font-weight: 700;
    color: var(--dark);
    margin-bottom: 14px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.pi-section-block h4 i {
    color: var(--primary);
    font-size: 0.9rem;
}

.pi-list li {
    padding: 6px 0;
    font-size: 0.9rem;
    color: var(--gray-500);
    position: relative;
    padding-left: 16px;
}

.pi-list li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 14px;
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: var(--primary-light);
}

/* ========================================
   RESEARCH
   ======================================== */
.research {
    background: var(--gray-50);
}

.research-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
}

.research-card {
    background: var(--white);
    border-radius: var(--radius-lg);
    padding: 40px;
    border: 1px solid var(--gray-200);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.research-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--gradient-1);
    opacity: 0;
    transition: var(--transition);
}

.research-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-200);
}

.research-card:hover::before {
    opacity: 1;
}

.research-card-number {
    font-size: 3.5rem;
    font-weight: 800;
    color: var(--gray-100);
    position: absolute;
    top: 16px;
    right: 24px;
    line-height: 1;
}

.research-card-icon {
    width: 64px;
    height: 64px;
    border-radius: var(--radius-md);
    background: var(--primary-50);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    color: var(--primary);
    margin-bottom: 20px;
    transition: var(--transition);
}

.research-card:hover .research-card-icon {
    background: var(--gradient-1);
    color: var(--white);
}

.research-card h3 {
    font-size: 1.3rem;
    font-weight: 700;
    color: var(--dark);
    margin-bottom: 4px;
}

.research-card-en {
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--primary-light);
    letter-spacing: 1px;
    display: block;
    margin-bottom: 14px;
}

.research-card p {
    color: var(--gray-500);
    font-size: 0.9rem;
    line-height: 1.8;
    margin-bottom: 20px;
}

.research-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.research-tags span {
    padding: 4px 12px;
    background: var(--gray-100);
    color: var(--gray-500);
    font-size: 0.75rem;
    font-weight: 500;
    border-radius: 50px;
    transition: var(--transition);
}

.research-card:hover .research-tags span {
    background: var(--primary-50);
    color: var(--primary);
}

/* ========================================
   MEMBERS
   ======================================== */
.members {
    background: var(--white);
}

.members-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
    margin-bottom: 40px;
}

.member-card {
    background: var(--white);
    border-radius: var(--radius-lg);
    padding: 40px 32px;
    border: 1px solid var(--gray-200);
    text-align: center;
    transition: var(--transition);
}

.member-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-200);
}

.member-pi {
    border-color: var(--primary-200);
    background: var(--primary-50);
}

.member-avatar {
    width: 88px;
    height: 88px;
    border-radius: 50%;
    background: var(--gray-100);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    color: var(--gray-400);
    margin: 0 auto 20px;
    transition: var(--transition);
}

.member-pi .member-avatar:not(.member-avatar-photo) {
    background: var(--gradient-1);
    color: var(--white);
}

.member-avatar-photo {
    overflow: hidden;
    padding: 0;
    background: var(--gray-100) !important;
}

.member-avatar-photo img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center top;
}

.member-card:hover .member-avatar {
    background: var(--gradient-1);
    color: var(--white);
}

.member-info h3 {
    font-size: 1.3rem;
    font-weight: 700;
    color: var(--dark);
    margin-bottom: 4px;
}

.member-name-en {
    display: block;
    font-size: 0.8rem;
    color: var(--gray-400);
    font-weight: 400;
    margin-bottom: 8px;
}

.member-role {
    display: inline-block;
    padding: 4px 14px;
    background: var(--primary-50);
    color: var(--primary);
    font-size: 0.8rem;
    font-weight: 600;
    border-radius: 50px;
    margin-bottom: 12px;
}

.member-desc {
    font-size: 0.85rem;
    color: var(--gray-500);
    line-height: 1.6;
}

.member-email {
    font-size: 0.78rem;
    margin-top: 4px;
}

.member-email a {
    color: var(--gray-400);
    transition: var(--transition);
}

.member-email a:hover {
    color: var(--primary);
    text-decoration: underline;
}

/* Join Banner */
.join-banner {
    background: var(--gradient-3);
    border: 2px dashed var(--primary-200);
    border-radius: var(--radius-lg);
    padding: 32px 40px;
}

.join-content {
    display: flex;
    align-items: center;
    gap: 20px;
}

.join-content > i {
    font-size: 2rem;
    color: var(--primary);
}

.join-content h4 {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--dark);
    margin-bottom: 4px;
}

.join-content p {
    font-size: 0.9rem;
    color: var(--gray-500);
}

.join-content .btn {
    margin-left: auto;
    white-space: nowrap;
}

/* ========================================
   PUBLICATIONS
   ======================================== */
.publications {
    background: var(--gray-50);
}

.publications-list {
    max-width: 900px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.pub-card {
    display: flex;
    align-items: flex-start;
    gap: 24px;
    background: var(--white);
    border-radius: var(--radius-md);
    padding: 28px 32px;
    border: 1px solid var(--gray-200);
    transition: var(--transition);
}

.pub-card:hover {
    transform: translateX(4px);
    border-color: var(--primary-200);
    box-shadow: var(--shadow-md);
}

.pub-year {
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--primary);
    background: var(--primary-50);
    padding: 4px 14px;
    border-radius: 50px;
    white-space: nowrap;
    flex-shrink: 0;
    margin-top: 2px;
}

.pub-content h4 {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--dark);
    line-height: 1.6;
    margin-bottom: 8px;
}

.pub-journal {
    font-size: 0.8rem;
    color: var(--gray-500);
    display: flex;
    align-items: center;
    gap: 6px;
}

.pub-journal i {
    color: var(--primary-light);
    font-size: 0.75rem;
}

.pub-more {
    text-align: center;
    margin-top: 40px;
}

.pub-more .btn-outline,
.pub-more .btn-outline-dark {
    color: var(--primary);
    border-color: var(--primary-200);
}

.pub-more .btn-outline:hover,
.pub-more .btn-outline-dark:hover {
    background: var(--primary);
    color: var(--white);
    border-color: var(--primary);
}

/* Subsection Title */
.subsection {
    margin-top: 72px;
    margin-bottom: 32px;
}

.subsection-title {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--dark);
    display: flex;
    align-items: center;
    gap: 12px;
    padding-bottom: 16px;
    border-bottom: 2px solid var(--gray-200);
}

.subsection-title i {
    color: var(--primary);
    font-size: 1.2rem;
}

/* ========================================
   NEWS (inside Research section)
   ======================================== */
.news-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.news-card {
    background: var(--white);
    border-radius: var(--radius-lg);
    padding: 32px;
    border: 1px solid var(--gray-200);
    transition: var(--transition);
    display: block;
    position: relative;
}

.news-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-200);
}

.news-badge {
    position: absolute;
    top: 16px;
    right: 16px;
    padding: 2px 10px;
    background: #ef4444;
    color: var(--white);
    font-size: 0.65rem;
    font-weight: 700;
    border-radius: 50px;
    letter-spacing: 1px;
}

.news-icon {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-sm);
    background: var(--primary-50);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    color: var(--primary);
    margin-bottom: 20px;
}

.news-card:hover .news-icon {
    background: var(--gradient-1);
    color: var(--white);
}

.news-card h4 {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--dark);
    line-height: 1.7;
    margin-bottom: 12px;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.news-source {
    font-size: 0.8rem;
    color: var(--gray-400);
    font-weight: 500;
}

/* ========================================
   SPINE AI PLATFORM
   ======================================== */
.spine-ai {
    background: var(--gray-50);
}

/* Platform Hero Visual */
.platform-hero {
    display: flex;
    justify-content: center;
    margin-bottom: 48px;
}

.platform-visual {
    position: relative;
    width: 200px;
    height: 200px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.platform-icon-main {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    background: var(--gradient-1);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    color: var(--white);
    z-index: 2;
    position: relative;
    box-shadow: 0 8px 30px rgba(26, 86, 219, 0.3);
}

.platform-ring {
    position: absolute;
    border-radius: 50%;
    border: 1px solid rgba(26, 86, 219, 0.12);
}

.platform-ring-1 {
    width: 120px;
    height: 120px;
    animation: ring-pulse 3s ease-in-out infinite;
}

.platform-ring-2 {
    width: 160px;
    height: 160px;
    animation: ring-pulse 3s ease-in-out 0.5s infinite;
}

.platform-ring-3 {
    width: 200px;
    height: 200px;
    animation: ring-pulse 3s ease-in-out 1s infinite;
}

@keyframes ring-pulse {
    0%, 100% { opacity: 0.3; transform: scale(1); }
    50% { opacity: 0.8; transform: scale(1.05); }
}

.platform-orbit-icon {
    position: absolute;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: var(--white);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.9rem;
    color: var(--primary);
    box-shadow: var(--shadow-md);
    z-index: 3;
}

.orbit-1 { top: 0; left: 50%; transform: translateX(-50%); }
.orbit-2 { right: 0; top: 50%; transform: translateY(-50%); }
.orbit-3 { bottom: 0; left: 50%; transform: translateX(-50%); }
.orbit-4 { left: 0; top: 50%; transform: translateY(-50%); }

/* Platform Overview */
.platform-overview {
    max-width: 900px;
    margin: 0 auto 56px;
    text-align: center;
}

.platform-overview p {
    font-size: 1.05rem;
    line-height: 2;
    color: var(--gray-500);
}

.platform-overview strong {
    color: var(--primary);
}

.platform-overview em {
    font-style: normal;
    font-weight: 600;
    color: var(--dark);
}

/* Platform Features */
.platform-features {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
    margin-bottom: 56px;
}

.platform-feature {
    background: var(--white);
    border-radius: var(--radius-lg);
    padding: 36px 28px;
    border: 1px solid var(--gray-200);
    transition: var(--transition);
    text-align: center;
}

.platform-feature:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-200);
}

.platform-feature-icon {
    width: 56px;
    height: 56px;
    border-radius: var(--radius-md);
    background: var(--primary-50);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.3rem;
    color: var(--primary);
    margin: 0 auto 18px;
    transition: var(--transition);
}

.platform-feature:hover .platform-feature-icon {
    background: var(--gradient-1);
    color: var(--white);
}

.platform-feature h4 {
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--dark);
    margin-bottom: 10px;
}

.platform-feature p {
    font-size: 0.85rem;
    color: var(--gray-500);
    line-height: 1.7;
}

/* Platform Pipeline */
.platform-pipeline {
    background: var(--white);
    border-radius: var(--radius-xl);
    padding: 40px;
    border: 1px solid var(--gray-200);
    box-shadow: var(--shadow-sm);
}

.pipeline-title {
    text-align: center;
    font-size: 1rem;
    font-weight: 700;
    color: var(--dark);
    margin-bottom: 32px;
    letter-spacing: 1px;
    text-transform: uppercase;
}

.pipeline-steps {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    flex-wrap: wrap;
}

.pipeline-step {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
    min-width: 90px;
}

.pipeline-step-icon {
    width: 56px;
    height: 56px;
    border-radius: 50%;
    background: var(--gradient-1);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    color: var(--white);
    box-shadow: 0 4px 15px rgba(26, 86, 219, 0.25);
}

.pipeline-step span {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--dark);
    white-space: nowrap;
}

.pipeline-arrow {
    color: var(--gray-300);
    font-size: 0.9rem;
    margin-bottom: 20px;
}

/* Platform CTA */
.platform-cta {
    text-align: center;
    margin-top: 48px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 14px;
}

.btn-platform {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 16px 36px;
    border-radius: var(--radius-md);
    font-size: 1.05rem;
    font-weight: 700;
    font-family: var(--font-main);
    background: var(--gradient-1);
    color: var(--white);
    border: none;
    cursor: not-allowed;
    opacity: 0.55;
    box-shadow: 0 4px 15px rgba(26, 86, 219, 0.2);
    transition: var(--transition);
}

.platform-cta-note {
    font-size: 0.82rem;
    color: var(--gray-400);
    display: flex;
    align-items: center;
    gap: 6px;
}

.platform-cta-note i {
    color: var(--warning);
}

/* ========================================
   CONTACT / LOCATION
   ======================================== */
.location {
    background: var(--white);
}

.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1.2fr;
    gap: 40px;
    align-items: start;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.contact-item {
    display: flex;
    gap: 16px;
    align-items: flex-start;
    background: var(--white);
    padding: 24px;
    border-radius: var(--radius-md);
    border: 1px solid var(--gray-200);
    transition: var(--transition);
}

.contact-item:hover {
    border-color: var(--primary-200);
    box-shadow: var(--shadow-md);
}

.contact-icon {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-sm);
    background: var(--primary-50);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    color: var(--primary);
    flex-shrink: 0;
}

.contact-item h4 {
    font-size: 0.9rem;
    font-weight: 700;
    color: var(--dark);
    margin-bottom: 4px;
}

.contact-item p {
    font-size: 0.85rem;
    color: var(--gray-500);
    line-height: 1.7;
}

.contact-email {
    color: var(--primary);
    font-weight: 500;
    transition: var(--transition);
}

.contact-email:hover {
    color: var(--primary-dark);
    text-decoration: underline;
}

.contact-map {
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--gray-200);
}

/* ========================================
   FOOTER
   ======================================== */
.footer {
    background: var(--dark);
    color: rgba(255,255,255,0.6);
    padding: 48px 0 0;
}

.footer-content {
    text-align: center;
    padding-bottom: 32px;
}

.footer-logo {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 16px;
}

.footer-logo .logo-text {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--white);
}

.footer-desc {
    font-size: 0.9rem;
    margin-bottom: 8px;
}

.footer-address {
    font-size: 0.85rem;
}

.footer-address i,
.footer-email i {
    margin-right: 6px;
    color: var(--primary-light);
}

.footer-email {
    font-size: 0.85rem;
    margin-top: 6px;
}

.footer-email a {
    color: rgba(255,255,255,0.6);
    transition: var(--transition);
}

.footer-email a:hover {
    color: var(--primary-light);
}

.footer-bottom {
    border-top: 1px solid rgba(255,255,255,0.08);
    padding: 20px 0;
    text-align: center;
    font-size: 0.8rem;
}

/* ========================================
   BACK TO TOP
   ======================================== */
.back-to-top {
    position: fixed;
    bottom: 32px;
    right: 32px;
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: var(--gradient-1);
    color: var(--white);
    border: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1rem;
    box-shadow: 0 4px 15px rgba(26, 86, 219, 0.3);
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: var(--transition);
    z-index: 999;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 25px rgba(26, 86, 219, 0.4);
}

/* ========================================
   PARTICLE (Hero Background)
   ======================================== */
.particle {
    position: absolute;
    border-radius: 50%;
    pointer-events: none;
    opacity: 0;
    animation: particle-float linear infinite;
}

@keyframes particle-float {
    0% {
        opacity: 0;
        transform: translateY(0) scale(0);
    }
    10% {
        opacity: 1;
    }
    90% {
        opacity: 1;
    }
    100% {
        opacity: 0;
        transform: translateY(-100vh) scale(1);
    }
}

/* ========================================
   RESPONSIVE
   ======================================== */
@media (max-width: 1024px) {
    .hero-title-main {
        font-size: 3.5rem;
    }
    
    .research-grid {
        grid-template-columns: 1fr 1fr;
    }
    
    .news-grid {
        grid-template-columns: 1fr 1fr;
    }

    .members-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .platform-features {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .section {
        padding: 72px 0;
    }

    .section-title {
        font-size: 2rem;
    }

    /* Navbar Mobile */
    .nav-toggle {
        display: flex;
    }

    .nav-menu {
        position: fixed;
        top: 0;
        right: -100%;
        width: 280px;
        height: 100vh;
        background: var(--white);
        flex-direction: column;
        padding: 100px 32px 32px;
        gap: 0;
        box-shadow: -10px 0 40px rgba(0,0,0,0.1);
        transition: var(--transition);
    }

    .nav-menu.open {
        right: 0;
    }

    .nav-link {
        color: var(--dark) !important;
        padding: 12px 16px;
        width: 100%;
        border-radius: var(--radius-sm);
    }

    .nav-link:hover,
    .nav-link.active {
        background: var(--primary-50) !important;
        color: var(--primary) !important;
    }

    .nav-toggle.open span:nth-child(1) {
        transform: rotate(45deg) translate(5px, 5px);
    }

    .nav-toggle.open span:nth-child(2) {
        opacity: 0;
    }

    .nav-toggle.open span:nth-child(3) {
        transform: rotate(-45deg) translate(5px, -5px);
    }

    .nav-toggle.open span {
        background: var(--dark) !important;
    }

    /* Hero Mobile */
    .hero-title-main {
        font-size: 2.5rem;
    }

    .hero-title-sub {
        font-size: 0.9rem;
    }

    .hero-description {
        font-size: 1rem;
    }

    .hero-stats {
        flex-direction: column;
        gap: 20px;
        padding: 24px 32px;
    }

    .stat-divider {
        width: 40px;
        height: 1px;
    }

    .stat-number {
        font-size: 2rem;
    }

    /* About */
    .about-grid {
        grid-template-columns: 1fr;
    }

    /* PI */
    .pi-info {
        flex-direction: column;
        text-align: center;
        padding: 32px;
    }

    .pi-details h3 {
        font-size: 1.4rem;
    }

    .pi-name-en {
        display: block;
        margin-left: 0;
        margin-top: 4px;
    }

    .pi-content {
        grid-template-columns: 1fr;
        padding: 32px;
        gap: 24px;
    }

    /* Research */
    .research-grid {
        grid-template-columns: 1fr;
    }

    /* Members */
    .members-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    /* News */
    .news-grid {
        grid-template-columns: 1fr;
    }

    /* Join Banner */
    .join-content {
        flex-direction: column;
        text-align: center;
    }

    .join-content .btn {
        margin-left: 0;
    }

    /* Contact */
    .contact-grid {
        grid-template-columns: 1fr;
    }

    /* Spine AI */
    .platform-features {
        grid-template-columns: 1fr;
    }

    .pipeline-steps {
        gap: 4px;
    }

    .pipeline-step {
        min-width: 70px;
    }

    .pipeline-step-icon {
        width: 44px;
        height: 44px;
        font-size: 1rem;
    }

    .pipeline-step span {
        font-size: 0.7rem;
    }

    /* Publications */
    .pub-card {
        flex-direction: column;
        gap: 12px;
    }
}

@media (max-width: 480px) {
    .hero-title-main {
        font-size: 2rem;
    }

    .hero-actions {
        flex-direction: column;
        align-items: center;
    }

    .hero-badge {
        font-size: 0.75rem;
    }

    .container {
        padding: 0 16px;
    }

    .section-header {
        margin-bottom: 48px;
    }

    .members-grid {
        grid-template-columns: 1fr;
    }
}