/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #2563eb;
    --primary-dark: #1e40af;
    --secondary-color: #10b981;
    --accent-color: #f59e0b;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --text-light: #9ca3af;
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-alt: #f3f4f6;
    --border-color: #e5e7eb;
    --link-color: #0066cc;
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
}

html, body {
    height: 100vh;
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    font-size: 14px;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
}

/* Header and Navigation */
.header {
    background-color: white;
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    flex-shrink: 0;
    height: 60px;
}

.navbar {
    padding: 0.75rem 0;
    height: 100%;
}

.nav-content {
    max-width: 100%;
    margin: 0 auto;
    padding: 0 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 100%;
}

.nav-logo {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--primary-color);
    width: 35px;
    height: 35px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 2px solid var(--primary-color);
    border-radius: 50%;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 1rem;
    margin: 0;
    padding: 0;
}

.nav-menu a {
    font-weight: 500;
    color: var(--text-primary);
    text-decoration: none;
    font-size: 0.75rem;
    transition: color 0.2s ease;
    padding: 0.25rem 0;
    white-space: nowrap;
}

.nav-menu a:hover {
    color: var(--primary-color);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 3px;
}

.nav-toggle span {
    width: 20px;
    height: 2px;
    background-color: var(--text-primary);
    transition: all 0.3s ease;
}

/* Main Content - Three Column Layout */
.main-content {
    flex: 1;
    display: flex;
    height: calc(100vh - 60px);
    overflow: hidden;
    margin: 0 50px;
}

.container {
    display: flex;
    width: 100%;
    height: 100%;
    padding: 0;
}

/* Three Column Layout */
.columns {
    display: flex;
    flex-direction: row;
    width: 100%;
    height: 100%;
}

.column {
    overflow-y: auto;
    overflow-x: hidden;
    padding: 1rem;
}

.left-column {
    width: 25%;
    flex: 0 0 25%;
    border-right: 1px solid var(--border-color);
    background-color: var(--bg-secondary);
}

.middle-column {
    width: 25%;
    flex: 0 0 25%;
    border-right: 1px solid var(--border-color);
}

.right-column {
    width: 50%;
    flex: 0 0 50%;
    overflow-y: auto;
    overflow-x: hidden;
}

/* Profile Section */
.profile-section {
    height: 100%;
}

.profile-image {
    text-align: center;
    margin-bottom: 1rem;
}

.oval-image {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    object-fit: cover;
    border: 3px solid var(--border-color);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.profile-info h2 {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.25rem;
    text-align: center;
}

.profile-info p {
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: 1rem;
    line-height: 1.4;
    font-size: 0.8rem;
}

.section-title {
    font-size: 0.90rem;
    font-weight: bold;
    margin-top: 1rem;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
    display: block;
}

.contact-section,
.social-section,
.interests-section {
    margin-bottom: 1rem;
}

.contact-section,
.social-section {
    font-size: 0.85rem;
}

.contact-section a,
.social-section a {
    color: var(--link-color);
    text-decoration: none;
}

.contact-section a:hover,
.social-section a:hover {
    text-decoration: underline;
}

.social-section .fa-2x {
    margin-right: 0.25rem;
    color: var(--text-secondary);
    transition: color 0.2s ease;
    font-size: 1.2rem;
}

.social-section .fa-2x:hover {
    color: var(--primary-color);
}

.interests-list {
    list-style: none;
    padding-left: 0;
    margin-top: 0.35rem;
}

.interests-list li {
    position: relative;
    padding-left: 0.8rem;
    margin-bottom: 0.25rem;
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.interests-list li::before {
    content: '▸';
    position: absolute;
    left: 0;
    color: var(--primary-color);
    font-weight: bold;
}

/* Middle Column - Quick Links */
.quick-links-section {
    padding: 1rem;
}

.quick-link {
    display: block;
    padding: 0.75rem;
    margin-bottom: 0.5rem;
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    text-decoration: none;
    color: var(--text-primary);
    transition: all 0.2s ease;
    font-size: 0.8rem;
}

.quick-link:hover {
    background-color: var(--primary-color);
    color: white;
    transform: translateX(4px);
}

.quick-link h3 {
    font-size: 0.9rem;
    font-weight: 600;
    margin-bottom: 0.25rem;
}

.quick-link p {
    font-size: 0.7rem;
    color: var(--text-secondary);
    margin: 0;
}

.quick-link:hover p {
    color: rgba(255, 255, 255, 0.9);
}

/* Content Sections */
.content-section {
    margin-bottom: 2rem;
    padding: 1rem;
}

.section-heading {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.75rem;
    padding-bottom: 0.25rem;
    border-bottom: 2px solid var(--border-color);
}

.content-section p {
    margin-bottom: 0.75rem;
    color: var(--text-secondary);
    text-align: justify;
    font-size: 0.95rem;
}

/* Research Items */
.research-item,
.education-item,
.experience-item {
    margin-bottom: 1.5rem;
    padding-left: 0.75rem;
    border-left: 3px solid var(--primary-color);
}

.research-item h3,
.education-item h3,
.experience-item h3 {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.25rem;
}

.research-period,
.experience-date {
    color: var(--text-secondary);
    font-size: 0.75rem;
    margin-bottom: 0.75rem;
    font-weight: 500;
}

.education-institution,
.experience-company {
    color: var(--text-primary);
    font-weight: 600;
    margin-bottom: 0.25rem;
    font-size: 0.8rem;
}

.education-date {
    color: var(--text-secondary);
    font-size: 0.75rem;
    margin-bottom: 0.25rem;
}

.education-gpa {
    color: var(--primary-color);
    font-weight: 600;
    margin-bottom: 0;
    font-size: 0.8rem;
}

.research-list,
.experience-list {
    list-style: none;
    padding-left: 0;
    margin-top: 0.75rem;
}

.research-list li,
.experience-list li {
    position: relative;
    padding-left: 1rem;
    margin-bottom: 0.25rem;
    color: var(--text-secondary);
    font-size: 0.90rem;
}

.research-list li::before,
.experience-list li::before {
    content: '▸';
    position: absolute;
    left: 0;
    color: var(--primary-color);
    font-weight: bold;
}

/* Publications */
.publication-item {
    margin-top: 1.5rem;
}

.publication-item h3 {
    font-size: 0.90rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.75rem;
    padding-bottom: 0.25rem;
    border-bottom: 1px solid var(--border-color);
}

.publication {
    margin-bottom: 0.75rem;
}

.publication p {
    font-size: 0.90rem;
}

.publication-venue {
    color: var(--text-secondary);
    font-style: italic;
    margin-top: 0.25rem;
    font-size: 0.7rem;
}

/* Skills Grid */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 0.75rem;
    margin-top: 0.75rem;
}

.skill-category {
    padding: 0.75rem;
    background-color: var(--bg-secondary);
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
}

.skill-category h3 {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: 0.25rem;
}

.skill-category p {
    color: var(--text-secondary);
    font-size: 0.80rem;
    margin-bottom: 0;
}

/* Languages */
#languages {
    font-size: 0.8rem;
}

#languages strong {
    color: var(--text-primary);
}

/* Back to Top Button - Hidden in new layout */
.back-to-top {
    display: none !important;
}

/* Scrollbar Styling */
.column::-webkit-scrollbar {
    width: 6px;
}

.column::-webkit-scrollbar-track {
    background: var(--bg-secondary);
}

.column::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 3px;
}

.column::-webkit-scrollbar-thumb:hover {
    background: var(--text-light);
}

/* Responsive Design */
@media (max-width: 1200px) {
    .left-column {
        width: 30%;
        flex: 0 0 30%;
    }
    
    .middle-column {
        width: 20%;
        flex: 0 0 20%;
    }
    
    .right-column {
        width: 50%;
        flex: 0 0 50%;
    }
}

@media (max-width: 768px) {
    html, body {
        height: auto;
        overflow: auto;
    }
    
    body {
        font-size: 20px;
    }
    
    .main-content {
        height: auto;
        display: block;
    }
    
    .columns {
        flex-direction: column;
        height: auto;
    }
    
    .left-column,
    .middle-column,
    .right-column {
        width: 100%;
        flex: 1 1 100%;
        border-right: none;
        border-bottom: 1px solid var(--border-color);
    }
    
    .nav-menu {
        position: fixed;
        top: 60px;
        left: 0;
        right: 0;
        background-color: white;
        flex-direction: column;
        padding: 2rem;
        box-shadow: var(--shadow-lg);
        transform: translateX(-100%);
        transition: transform 0.3s ease;
        gap: 1rem;
        border-top: 1px solid var(--border-color);
    }
    
    .nav-menu.active {
        transform: translateX(0);
    }
    
    .nav-toggle {
        display: flex;
    }
    
    .nav-toggle.active span:nth-child(1) {
        transform: rotate(45deg) translate(3px, 3px);
    }
    
    .nav-toggle.active span:nth-child(2) {
        opacity: 0;
    }
    
    .nav-toggle.active span:nth-child(3) {
        transform: rotate(-45deg) translate(3px, -3px);
    }
    
    .column {
        overflow-y: visible;
    }
}

@media (max-width: 480px) {
    .column {
        padding: 0.75rem;
    }
    
    .nav-content {
        padding: 0 0.75rem;
    }
    
    .profile-info h2 {
        font-size: 1.1rem;
    }
    
    .section-heading {
        font-size: 1rem;
    }
    
    .skills-grid {
        grid-template-columns: 1fr;
    }
}

/* Print Styles */
@media print {
    .header {
        display: none !important;
    }
    
    body {
        font-size: 10pt;
        line-height: 1.3;
        margin: 0;
        padding: 0;
        height: auto;
        overflow: visible;
    }
    
    .main-content {
        height: auto;
        display: block;
    }
    
    .columns {
        flex-direction: column;
        height: auto;
    }
    
    .left-column,
    .middle-column,
    .right-column {
        width: 100%;
        flex: 1 1 100%;
        border: none;
        page-break-inside: avoid;
    }
    
    .content-section {
        break-inside: avoid;
        margin-bottom: 1.5rem;
    }
}

/* Focus Styles */
a:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* Selection */
::selection {
    background-color: var(--primary-color);
    color: white;
}