/* ===================================
   MODERN ACADEMIC WEBSITE STYLES
   =================================== */

/* CSS Variables */
:root {
    --primary-color: #EAB308;
    --secondary-color: #CA8A04;
    --accent-color: #FACC15;
    --dark-bg: #111111;
    --darker-bg: #0A0A0A;
    --light-bg: #F9F9F9;
    --text-primary: #1A1A1A;
    --text-secondary: #6B6B6B;
    --text-light: #9CA3AF;
    --gradient-1: linear-gradient(135deg, #EAB308 0%, #CA8A04 100%);
    --gradient-2: linear-gradient(135deg, #EAB308 0%, #A16207 100%);
    --font-primary: 'Inter', sans-serif;
    --font-heading: 'Playfair Display', serif;
}

/* Global Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: var(--font-primary);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.2;
}

a {
    text-decoration: none;
    transition: all 0.3s ease;
}

section {
    padding: 80px 0;
}

/* ===================================
   NAVIGATION
   =================================== */

#mainNav {
    padding: 20px 0;
    background: rgba(17, 17, 17, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 20px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
}

#mainNav.scrolled {
    padding: 10px 0;
    background: rgba(17, 17, 17, 0.98);
}

.navbar-brand {
    font-size: 1.8rem;
    font-weight: 700;
}

.brand-name {
    background: linear-gradient(135deg, #EAB308 0%, #CA8A04 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.navbar-nav .nav-link {
    color: rgba(255, 255, 255, 0.8);
    font-weight: 500;
    padding: 8px 20px;
    margin: 0 5px;
    border-radius: 8px;
    transition: all 0.3s ease;
}

.navbar-nav .nav-link:hover,
.navbar-nav .nav-link.active {
    color: #fff;
    background: rgba(255, 255, 255, 0.1);
}

/* ===================================
   HERO SECTION
   =================================== */

.hero-section {
    background: linear-gradient(135deg, #111111 0%, #1A1A1A 100%);
    color: white;
    position: relative;
    overflow: hidden;
    padding-top: 80px;
}

.hero-content {
    position: relative;
    z-index: 2;
}

.badge-tag {
    display: inline-block;
    padding: 8px 20px;
    background: rgba(249, 115, 22, 0.2);
    border: 1px solid rgba(249, 115, 22, 0.4);
    border-radius: 50px;
    font-size: 0.9rem;
    font-weight: 500;
    margin-bottom: 20px;
    color: #FEF08A;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 20px;
    font-family: var(--font-heading);
}

.hero-title .highlight {
    background: linear-gradient(135deg, #EAB308 0%, #CA8A04 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.2rem;
    color: rgba(255, 255, 255, 0.8);
    margin-bottom: 30px;
    line-height: 1.8;
}

.hero-buttons {
    margin-bottom: 40px;
}

.btn-primary {
    background: linear-gradient(135deg, #EAB308 0%, #CA8A04 100%);
    border: none;
    padding: 12px 30px;
    font-weight: 600;
    border-radius: 10px;
    transition: all 0.3s ease;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(249, 115, 22, 0.4);
}

.btn-outline-light {
    border: 2px solid rgba(255, 255, 255, 0.3);
    padding: 12px 30px;
    font-weight: 600;
    border-radius: 10px;
    transition: all 0.3s ease;
}

.btn-outline-light:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: rgba(255, 255, 255, 0.5);
    transform: translateY(-2px);
}

.hero-stats {
    padding-top: 30px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

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

.stat-number {
    font-size: 2rem;
    font-weight: 700;
    background: linear-gradient(135deg, #EAB308 0%, #CA8A04 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 5px;
}

.stat-label {
    font-size: 0.9rem;
    color: rgba(255, 255, 255, 0.6);
    margin: 0;
}

/* Hero Image */
.hero-image {
    position: relative;
    z-index: 2;
}

.profile-card {
    background: rgba(255, 255, 255, 0.05);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 20px;
    padding: 40px;
    text-align: center;
    transition: all 0.3s ease;
}

.profile-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
}

.profile-placeholder {
    width: 200px;
    height: 200px;
    margin: 0 auto 20px;
    background: linear-gradient(135deg, #EAB308 0%, #CA8A04 100%);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 8rem;
    color: white;
}

.profile-info h3 {
    font-size: 1.5rem;
    margin-bottom: 5px;
}

.profile-info p {
    color: rgba(255, 255, 255, 0.7);
    margin-bottom: 20px;
}

.social-links {
    display: flex;
    justify-content: center;
    gap: 15px;
}

.social-link {
    width: 45px;
    height: 45px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.2rem;
    transition: all 0.3s ease;
}

.social-link:hover {
    background: linear-gradient(135deg, #EAB308 0%, #CA8A04 100%);
    transform: translateY(-3px);
    color: white;
}

.scroll-indicator {
    position: absolute;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 3;
}

.scroll-indicator a {
    color: rgba(255, 255, 255, 0.5);
    font-size: 2rem;
}

/* ===================================
   SECTION STYLES
   =================================== */

.section-header {
    margin-bottom: 60px;
}

.section-tag {
    display: inline-block;
    padding: 6px 18px;
    background: rgba(249, 115, 22, 0.1);
    border: 1px solid rgba(249, 115, 22, 0.2);
    border-radius: 50px;
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 15px;
    color: var(--primary-color);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 15px;
    font-family: var(--font-heading);
}

.section-description {
    font-size: 1.1rem;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

.section-preview {
    padding: 100px 0;
}

.bg-light {
    background-color: var(--light-bg) !important;
}

/* ===================================
   OVERVIEW SECTION (Home Page)
   =================================== */

.overview-section {
    padding: 100px 0;
    background: linear-gradient(135deg, #111111 0%, #1A1A1A 100%);
}

.preview-card {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.08);
    border-radius: 20px;
    padding: 40px;
    height: 100%;
    transition: all 0.3s ease;
}

.preview-card:hover {
    background: rgba(255, 255, 255, 0.08);
    border-color: rgba(249, 115, 22, 0.3);
}

.preview-icon {
    width: 80px;
    height: 80px;
    margin-bottom: 25px;
    background: linear-gradient(135deg, #EAB308 0%, #CA8A04 100%);
    border-radius: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2.5rem;
    color: white;
}

.preview-card h3 {
    font-size: 1.8rem;
    margin-bottom: 15px;
    color: white;
}

.preview-card p {
    color: rgba(255, 255, 255, 0.65);
    margin-bottom: 20px;
    line-height: 1.7;
}

.preview-highlights {
    list-style: none;
    padding: 0;
    margin-bottom: 25px;
}

.preview-highlights li {
    padding: 8px 0;
    color: rgba(255, 255, 255, 0.65);
    font-size: 0.95rem;
}

.preview-highlights li i {
    color: #FEF08A;
    margin-right: 10px;
}

.overview-section .btn-outline-primary {
    border-color: rgba(255, 255, 255, 0.3);
    color: rgba(255, 255, 255, 0.85);
}

.overview-section .btn-outline-primary:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: rgba(255, 255, 255, 0.5);
    color: white;
}

.btn-outline-primary {
    border: 2px solid var(--primary-color);
    color: var(--primary-color);
    padding: 12px 30px;
    font-weight: 600;
    border-radius: 10px;
    transition: all 0.3s ease;
}

.btn-outline-primary:hover {
    background: linear-gradient(135deg, #EAB308 0%, #CA8A04 100%);
    border-color: transparent;
    color: white;
    transform: translateX(5px);
}

/* ===================================
   PAGE HEADER (For separate pages)
   =================================== */

.page-header {
    padding: 150px 0 80px;
    background: linear-gradient(135deg, #111111 0%, #1A1A1A 100%);
    color: white;
    position: relative;
}

.page-header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg width="100" height="100" xmlns="http://www.w3.org/2000/svg"><defs><pattern id="grid" width="40" height="40" patternUnits="userSpaceOnUse"><path d="M 40 0 L 0 0 0 40" fill="none" stroke="rgba(255,255,255,0.05)" stroke-width="1"/></pattern></defs><rect width="100" height="100" fill="url(%23grid)"/></svg>');
    opacity: 0.5;
}

.page-title {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 20px;
    font-family: var(--font-heading);
}

.page-subtitle {
    font-size: 1.2rem;
    color: rgba(255, 255, 255, 0.8);
    margin-bottom: 0;
}

/* ===================================
   CAREER SECTION
   =================================== */

.career-section {
    padding: 100px 0;
    background: var(--light-bg);
}

/* Career Cards */
.career-card {
    background: white;
    border-radius: 20px;
    padding: 40px 30px;
    text-align: center;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.05);
    transition: all 0.3s ease;
    height: 100%;
}

.career-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 40px rgba(249, 115, 22, 0.2);
}

.career-card-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 20px;
    background: linear-gradient(135deg, #EAB308 0%, #CA8A04 100%);
    border-radius: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2.5rem;
    color: white;
}

.career-card h4 {
    font-size: 1.5rem;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.career-card p {
    color: var(--text-secondary);
    margin-bottom: 0;
    line-height: 1.7;
}

/* Timeline */
.timeline-container {
    margin-top: 80px;
}

.timeline-header h3 {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 10px;
}

.timeline {
    position: relative;
    max-width: 1000px;
    margin: 0 auto;
    padding: 40px 0;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 50%;
    top: 0;
    bottom: 0;
    width: 3px;
    background: linear-gradient(180deg,
        rgba(249, 115, 22, 0.1) 0%,
        rgba(249, 115, 22, 0.5) 50%,
        rgba(249, 115, 22, 0.1) 100%);
    transform: translateX(-50%);
}

.timeline-item {
    position: relative;
    margin-bottom: 50px;
}

.timeline-item:last-child {
    margin-bottom: 0;
}

.timeline-marker {
    position: absolute;
    left: 50%;
    top: 30px;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: white;
    border: 4px solid var(--primary-color);
    transform: translateX(-50%);
    z-index: 2;
    transition: all 0.3s ease;
}

.timeline-marker.current {
    width: 30px;
    height: 30px;
    background: linear-gradient(135deg, #EAB308 0%, #CA8A04 100%);
    border: 4px solid white;
    box-shadow: 0 0 0 4px rgba(249, 115, 22, 0.3);
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% {
        box-shadow: 0 0 0 4px rgba(249, 115, 22, 0.3);
    }
    50% {
        box-shadow: 0 0 0 8px rgba(249, 115, 22, 0.1);
    }
}

.timeline-content {
    width: calc(50% - 40px);
    padding-right: 40px;
}

.timeline-item:nth-child(even) .timeline-content {
    margin-left: calc(50% + 40px);
    padding-right: 0;
    padding-left: 40px;
}

.timeline-card {
    background: white;
    border-radius: 15px;
    padding: 30px;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.08);
    transition: all 0.3s ease;
    border: 1px solid rgba(249, 115, 22, 0.1);
}

.timeline-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(249, 115, 22, 0.15);
}

.timeline-date {
    margin-bottom: 15px;
    display: flex;
    align-items: center;
    gap: 10px;
    flex-wrap: wrap;
}

.timeline-date .year {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-secondary);
}

.timeline-date .badge {
    padding: 6px 12px;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.bg-gradient-primary {
    background: linear-gradient(135deg, #EAB308 0%, #CA8A04 100%);
}

.timeline-card h4 {
    font-size: 1.4rem;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.timeline-card .institution {
    font-size: 0.95rem;
    color: var(--primary-color);
    margin-bottom: 15px;
    font-weight: 500;
}

.timeline-card .institution i {
    margin-right: 5px;
}

.timeline-card .description {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 20px;
}

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

.skill-tag {
    display: inline-block;
    padding: 6px 14px;
    background: rgba(249, 115, 22, 0.1);
    border: 1px solid rgba(249, 115, 22, 0.2);
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--primary-color);
    transition: all 0.3s ease;
}

.skill-tag:hover {
    background: linear-gradient(135deg, #EAB308 0%, #CA8A04 100%);
    color: white;
    border-color: transparent;
}

.download-cv-btn {
    padding: 15px 40px;
    font-size: 1.1rem;
    font-weight: 600;
}

/* Additional Content */
.additional-content .content-card {
    background: white;
    border-radius: 20px;
    padding: 40px;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.05);
}

.additional-content .content-card h3 {
    font-size: 1.8rem;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.additional-content .content-card h3 i {
    color: var(--primary-color);
    margin-right: 10px;
}

.achievement-item {
    padding: 20px;
    background: rgba(249, 115, 22, 0.05);
    border-radius: 15px;
    transition: all 0.3s ease;
}

.achievement-item:hover {
    background: rgba(249, 115, 22, 0.1);
}

.achievement-item h5 {
    font-size: 1.2rem;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.achievement-item p {
    color: var(--text-secondary);
    margin-bottom: 0;
}

/* ===================================
   TEACHING PAGE
   =================================== */

/* Teaching Philosophy Section */
.teaching-philosophy-section {
    padding: 100px 0;
    background: white;
}

.philosophy-content h2 {
    font-size: 2.5rem;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.philosophy-content .lead {
    font-size: 1.3rem;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.philosophy-points {
    margin-top: 30px;
}

.point-item {
    display: flex;
    align-items: start;
    margin-bottom: 25px;
}

.point-icon {
    width: 60px;
    height: 60px;
    min-width: 60px;
    background: linear-gradient(135deg, #EAB308 0%, #CA8A04 100%);
    border-radius: 15px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.8rem;
    color: white;
    margin-right: 20px;
}

.point-content h5 {
    font-size: 1.2rem;
    margin-bottom: 8px;
    color: var(--text-primary);
}

.point-content p {
    color: var(--text-secondary);
    margin-bottom: 0;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
}

.stat-card {
    background: white;
    border-radius: 20px;
    padding: 30px;
    text-align: center;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.08);
    transition: all 0.3s ease;
}

.stat-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(249, 115, 22, 0.2);
}

.stat-value {
    font-size: 2.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, #EAB308 0%, #CA8A04 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 10px;
}

.stat-label {
    font-size: 0.95rem;
    color: var(--text-secondary);
    font-weight: 500;
}

/* Courses Section */
.courses-section {
    padding: 100px 0;
    background: var(--light-bg);
}

.course-card {
    background: white;
    border-radius: 20px;
    padding: 30px;
    height: 100%;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.05);
    transition: all 0.3s ease;
    border: 1px solid rgba(0, 0, 0, 0.05);
}

.course-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 40px rgba(249, 115, 22, 0.2);
}

.course-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

.course-icon {
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, #EAB308 0%, #CA8A04 100%);
    border-radius: 15px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.8rem;
    color: white;
}

.course-level .badge {
    padding: 6px 14px;
    font-size: 0.75rem;
    font-weight: 600;
}

.course-card h3 {
    font-size: 1.5rem;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.course-description {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 20px;
}

.course-topics {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 20px;
}

.topic-tag {
    display: inline-block;
    padding: 5px 12px;
    background: rgba(249, 115, 22, 0.1);
    border: 1px solid rgba(249, 115, 22, 0.2);
    border-radius: 15px;
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--primary-color);
}

.course-footer {
    border-top: 1px solid rgba(0, 0, 0, 0.05);
    padding-top: 15px;
}

.course-info {
    display: flex;
    gap: 20px;
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.course-info span i {
    margin-right: 5px;
    color: var(--primary-color);
}

/* Materials Section */
.materials-section {
    padding: 100px 0;
    background: white;
}

.material-card {
    background: var(--light-bg);
    border-radius: 20px;
    padding: 40px;
    text-align: center;
    height: 100%;
    transition: all 0.3s ease;
}

.material-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(249, 115, 22, 0.15);
}

.material-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 20px;
    background: linear-gradient(135deg, #EAB308 0%, #CA8A04 100%);
    border-radius: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2.5rem;
    color: white;
}

.material-card h4 {
    font-size: 1.3rem;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.material-card p {
    color: var(--text-secondary);
    margin-bottom: 20px;
}

/* Institutions Section */
.institutions-section {
    padding: 100px 0;
    background: var(--light-bg);
}

.institution-card {
    background: white;
    border-radius: 20px;
    padding: 35px 30px;
    height: 100%;
    border-top: 4px solid var(--primary-color);
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.05);
    transition: all 0.3s ease;
}

.institution-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(249, 115, 22, 0.15);
}

.institution-logo {
    width: 60px;
    height: 60px;
    background: var(--gradient-2);
    border-radius: 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.6rem;
    color: white;
    margin-bottom: 20px;
}

.institution-card h4 {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 6px;
}

.institution-type {
    font-size: 0.78rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--primary-color);
    margin-bottom: 10px;
}

.institution-period {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: 14px;
}

.institution-period i {
    margin-right: 5px;
}

.institution-desc {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.65;
    margin-bottom: 0;
}

/* Feedback Section */
.feedback-section {
    padding: 100px 0;
    background: var(--light-bg);
}

.feedback-card {
    background: white;
    border-radius: 20px;
    padding: 30px;
    height: 100%;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.05);
    transition: all 0.3s ease;
}

.feedback-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(249, 115, 22, 0.15);
}

.rating {
    margin-bottom: 20px;
    color: #fbbf24;
    font-size: 1.2rem;
}

.feedback-text {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 20px;
    font-style: italic;
}

.feedback-author {
    border-top: 1px solid rgba(0, 0, 0, 0.05);
    padding-top: 15px;
}

.feedback-author strong {
    display: block;
    color: var(--text-primary);
    margin-bottom: 5px;
}

.feedback-author span {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

/* ===================================
   RESEARCH PAGE
   =================================== */

/* Research Overview Section */
.research-overview-section {
    padding: 100px 0;
    background: white;
}

.research-intro h2 {
    font-size: 2.5rem;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.research-intro .lead {
    font-size: 1.3rem;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.research-interests {
    margin-top: 30px;
}

.research-interests h5 {
    font-size: 1.2rem;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.interests-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 15px;
}

.interest-tag {
    display: flex;
    align-items: center;
    padding: 12px 15px;
    background: rgba(249, 115, 22, 0.1);
    border: 1px solid rgba(249, 115, 22, 0.2);
    border-radius: 10px;
    font-size: 0.95rem;
    font-weight: 500;
    color: var(--text-primary);
    transition: all 0.3s ease;
}

.interest-tag:hover {
    background: linear-gradient(135deg, #EAB308 0%, #CA8A04 100%);
    color: white;
    border-color: transparent;
}

.interest-tag i {
    color: var(--primary-color);
    margin-right: 10px;
    font-size: 1.1rem;
}

.research-metrics {
    background: var(--light-bg);
    border-radius: 20px;
    padding: 30px;
    height: 100%;
}

.research-metrics h5 {
    font-size: 1.3rem;
    margin-bottom: 25px;
    color: var(--text-primary);
}

.metric-item {
    display: flex;
    align-items: center;
    padding: 20px 0;
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
}

.metric-item:last-child {
    border-bottom: none;
}

.metric-icon {
    width: 50px;
    height: 50px;
    min-width: 50px;
    background: linear-gradient(135deg, #EAB308 0%, #CA8A04 100%);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    color: white;
    margin-right: 15px;
}

.metric-info {
    flex: 1;
}

.metric-value {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 5px;
}

.metric-label {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

/* Publications Section */
.publications-section {
    padding: 100px 0;
    background: var(--light-bg);
}

.publication-card {
    background: white;
    border-radius: 20px;
    padding: 30px;
    margin-bottom: 30px;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.05);
    display: flex;
    gap: 30px;
    transition: all 0.3s ease;
}

.publication-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(249, 115, 22, 0.15);
}

.pub-year {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    min-width: 70px;
}

.pub-content {
    flex: 1;
}

.pub-title {
    font-size: 1.4rem;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.pub-subtitle {
    font-size: 1.1rem;
    font-weight: 400;
    font-style: italic;
    margin-bottom: 15px;
}

.pub-authors {
    font-size: 0.95rem;
    color: var(--text-secondary);
    margin-bottom: 8px;
}

.pub-journal {
    font-size: 0.9rem;
    color: var(--primary-color);
    margin-bottom: 15px;
    font-weight: 500;
}

.pub-journal i {
    margin-right: 5px;
}

.pub-abstract {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 15px;
}

/* Publication Year Filter */
.pub-year-filter {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 35px;
}

.pub-filter-btn {
    padding: 8px 22px;
    border-radius: 50px;
    border: 2px solid var(--primary-color);
    background: transparent;
    color: var(--primary-color);
    font-family: var(--font-primary);
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.25s ease;
}

.pub-filter-btn:hover {
    background: var(--accent-color);
    border-color: var(--accent-color);
    color: white;
}

.pub-filter-btn.active {
    background: var(--primary-color);
    color: white;
}

.publication-card.pub-hidden {
    display: none !important;
}

.pub-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 15px;
}

.pub-tag {
    display: inline-block;
    padding: 5px 12px;
    background: rgba(249, 115, 22, 0.1);
    border: 1px solid rgba(249, 115, 22, 0.2);
    border-radius: 15px;
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--primary-color);
}

.pub-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    align-items: center;
}

.pub-citations {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-left: 10px;
}

.pub-citations i {
    color: var(--primary-color);
    margin-right: 5px;
}

/* Working Papers Section */
.working-papers-section {
    padding: 100px 0;
    background: white;
}

.working-paper-card {
    background: var(--light-bg);
    border-radius: 20px;
    padding: 30px;
    height: 100%;
    transition: all 0.3s ease;
    position: relative;
}

.working-paper-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(249, 115, 22, 0.15);
}

.wp-status {
    position: absolute;
    top: 20px;
    right: 20px;
}

.working-paper-card h4 {
    font-size: 1.3rem;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.wp-authors {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 15px;
}

.wp-description {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 15px;
}

.wp-date {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-bottom: 15px;
}

.wp-date i {
    margin-right: 5px;
    color: var(--primary-color);
}

.wp-actions {
    display: flex;
    gap: 10px;
}

/* PhD Thesis Section Styles */
.thesis-info-card {
    background: var(--light-bg);
    border-radius: 20px;
    padding: 40px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.05);
}

.thesis-info-card h4 {
    font-size: 1.8rem;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.thesis-info-card .lead {
    font-size: 1.1rem;
    line-height: 1.8;
    color: var(--text-secondary);
}

.thesis-theme {
    text-align: center;
    padding: 20px;
    background: white;
    border-radius: 15px;
    height: 100%;
    transition: all 0.3s ease;
}

.thesis-theme:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(249, 115, 22, 0.15);
}

.theme-icon {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 15px;
}

.thesis-theme h6 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.thesis-theme p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin: 0;
}

.thesis-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 15px;
}

.thesis-tag {
    background: white;
    color: var(--primary-color);
    padding: 8px 16px;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 500;
    border: 1px solid var(--primary-color);
    transition: all 0.3s ease;
}

.thesis-tag:hover {
    background: var(--primary-color);
    color: white;
}

/* Conferences Section */
.conferences-section {
    padding: 100px 0;
    background: var(--light-bg);
}

.conference-timeline {
    max-width: 800px;
    margin: 0 auto;
}

.conference-item {
    display: flex;
    gap: 30px;
    margin-bottom: 40px;
    padding-bottom: 40px;
    border-bottom: 1px solid rgba(0, 0, 0, 0.1);
}

.conference-item:last-child {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
}

.conf-date {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    min-width: 70px;
}

.conf-content {
    flex: 1;
}

.conf-content h5 {
    font-size: 1.2rem;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.conf-location {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 10px;
}

.conf-location i {
    margin-right: 5px;
    color: var(--primary-color);
}

.conf-presentation {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 0;
}

/* ===================================
   TOOLS PAGE
   =================================== */

/* Tools Introduction Section */
.tools-intro-section {
    padding: 100px 0;
    background: white;
}

.tools-intro-content h2 {
    font-size: 2.5rem;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.tools-intro-content .lead {
    font-size: 1.3rem;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.intro-features {
    margin-top: 30px;
}

.feature-item {
    display: flex;
    align-items: center;
    padding: 15px 0;
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
}

.feature-item:last-child {
    border-bottom: none;
}

.feature-item i {
    font-size: 1.5rem;
    color: var(--primary-color);
    margin-right: 15px;
    min-width: 30px;
}

.feature-item span {
    color: var(--text-secondary);
    font-size: 1rem;
}

.tools-stats-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
}

.tools-stat-card {
    background: white;
    border-radius: 20px;
    padding: 30px;
    text-align: center;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.08);
    transition: all 0.3s ease;
}

.tools-stat-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(249, 115, 22, 0.2);
}

.tools-stat-icon {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 15px;
}

.tools-stat-value {
    font-size: 2rem;
    font-weight: 700;
    background: linear-gradient(135deg, #EAB308 0%, #CA8A04 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 10px;
}

.tools-stat-label {
    font-size: 0.9rem;
    color: var(--text-secondary);
    font-weight: 500;
}

/* Tools Catalog Section */
.tools-catalog-section {
    padding: 100px 0;
    background: var(--light-bg);
}

.tool-card {
    background: white;
    border-radius: 20px;
    padding: 30px;
    height: 100%;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.05);
    transition: all 0.3s ease;
    position: relative;
    display: flex;
    flex-direction: column;
}

.tool-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 40px rgba(249, 115, 22, 0.2);
}

.tool-badge {
    position: absolute;
    top: 20px;
    right: 20px;
}

.tool-badge .badge {
    padding: 6px 12px;
    font-size: 0.75rem;
    font-weight: 600;
}

.tool-icon {
    width: 80px;
    height: 80px;
    margin-bottom: 20px;
    background: linear-gradient(135deg, #EAB308 0%, #CA8A04 100%);
    border-radius: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2.5rem;
    color: white;
}

.tool-card h4 {
    font-size: 1.4rem;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.tool-description {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 20px;
    flex: 1;
}

.tool-features {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 20px;
}

.feature-tag {
    display: inline-block;
    padding: 5px 10px;
    background: rgba(249, 115, 22, 0.1);
    border: 1px solid rgba(249, 115, 22, 0.2);
    border-radius: 15px;
    font-size: 0.7rem;
    font-weight: 500;
    color: var(--primary-color);
}

.feature-tag i {
    margin-right: 3px;
}

.tool-footer {
    margin-top: auto;
}

/* How to Use Section */
.how-to-use-section {
    padding: 100px 0;
    background: white;
}

.step-card {
    text-align: center;
    padding: 30px 20px;
}

.step-number {
    width: 60px;
    height: 60px;
    margin: 0 auto 20px;
    background: linear-gradient(135deg, #EAB308 0%, #CA8A04 100%);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.8rem;
    font-weight: 700;
    color: white;
}

.step-card h5 {
    font-size: 1.2rem;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.step-card p {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 0;
}

/* Tools Feedback Section */
.tools-feedback-section {
    padding: 80px 0;
    background: var(--light-bg);
}

.tools-feedback-section h3 {
    font-size: 2rem;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.tools-feedback-section p {
    font-size: 1.1rem;
    color: var(--text-secondary);
    margin-bottom: 0;
}

/* ===================================
   CONTACT SECTION
   =================================== */

.contact-section {
    background: linear-gradient(135deg, #111111 0%, #1A1A1A 100%);
    color: white;
    padding: 100px 0;
}

.contact-form .form-control {
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 10px;
    padding: 15px 20px;
    color: white;
    font-size: 1rem;
}

.contact-form .form-control::placeholder {
    color: rgba(255, 255, 255, 0.5);
}

.contact-form .form-control:focus {
    background: rgba(255, 255, 255, 0.15);
    border-color: rgba(249, 115, 22, 0.5);
    color: white;
    box-shadow: 0 0 0 0.2rem rgba(249, 115, 22, 0.2);
}

/* ===================================
   FOOTER
   =================================== */

.footer {
    background: var(--darker-bg);
    color: rgba(255, 255, 255, 0.7);
    padding: 40px 0;
}

.footer h5 {
    color: white;
    margin-bottom: 10px;
}

.social-links-footer {
    display: flex;
    gap: 15px;
    justify-content: flex-end;
}

.social-links-footer a {
    width: 40px;
    height: 40px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: rgba(255, 255, 255, 0.7);
    font-size: 1.1rem;
    transition: all 0.3s ease;
}

.social-links-footer a:hover {
    background: linear-gradient(135deg, #EAB308 0%, #CA8A04 100%);
    color: white;
}

.footer hr {
    border-color: rgba(255, 255, 255, 0.1);
}

/* ===================================
   RESPONSIVE DESIGN
   =================================== */

@media (max-width: 992px) {
    .hero-title {
        font-size: 2.5rem;
    }

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

    .social-links-footer {
        justify-content: flex-start;
        margin-top: 20px;
    }

    /* Career Timeline Responsive */
    .timeline::before {
        left: 30px;
    }

    .timeline-marker {
        left: 30px;
    }

    .timeline-content {
        width: 100%;
        padding-left: 80px;
        padding-right: 0;
    }

    .timeline-item:nth-child(even) .timeline-content {
        margin-left: 0;
        padding-left: 80px;
        padding-right: 0;
    }
}

@media (max-width: 768px) {
    .hero-title {
        font-size: 2rem;
    }

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

    .hero-buttons .btn {
        display: block;
        width: 100%;
        margin-bottom: 15px;
    }

    .hero-buttons .me-3 {
        margin-right: 0 !important;
    }

    .profile-placeholder {
        width: 150px;
        height: 150px;
        font-size: 6rem;
    }

    .stat-number {
        font-size: 1.5rem;
    }

    section {
        padding: 60px 0;
    }

    .section-preview {
        padding: 80px 0;
    }

    .career-section {
        padding: 80px 0;
    }

    .timeline-content {
        padding-left: 60px;
    }

    .timeline-item:nth-child(even) .timeline-content {
        padding-left: 60px;
    }

    .timeline-card {
        padding: 20px;
    }

    .timeline-card h4 {
        font-size: 1.2rem;
    }

    /* Teaching Page Responsive */
    .stats-grid {
        grid-template-columns: 1fr;
    }

    .point-item {
        flex-direction: column;
        text-align: center;
    }

    .point-icon {
        margin-right: 0;
        margin-bottom: 15px;
    }

    /* Research Page Responsive */
    .interests-grid {
        grid-template-columns: 1fr;
    }

    .publication-card {
        flex-direction: column;
        gap: 15px;
    }

    .pub-year {
        min-width: auto;
    }

    .conference-item {
        flex-direction: column;
        gap: 15px;
    }

    .conf-date {
        min-width: auto;
    }

    /* Tools Page Responsive */
    .tools-stats-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 576px) {
    .hero-title {
        font-size: 1.75rem;
    }

    .section-title {
        font-size: 1.75rem;
    }

    .navbar-brand {
        font-size: 1.5rem;
    }

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

    .page-subtitle {
        font-size: 1rem;
    }

    .philosophy-content h2 {
        font-size: 2rem;
    }

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

    .research-intro h2 {
        font-size: 2rem;
    }

    .tools-intro-content h2 {
        font-size: 2rem;
    }

    .pub-title {
        font-size: 1.2rem;
    }

    .metric-value {
        font-size: 1.5rem;
    }
}
/* ---------- App-page brand: clickable QAS.Science home link ---------- */
.topnav-brand {
  display: inline-flex;
  align-items: center;
  color: #fff;
  font-weight: 800;
  letter-spacing: .02em;
  text-decoration: none;
  font-size: 1rem;
  line-height: 1;
}
.topnav-brand span { color: #EAB308; }
.topnav-brand:hover { color: #EAB308; }
.topnav-brand:hover span { color: #fff; }