/* Base Styles */
:root {
    --primary-color: #0366d6;
    --secondary-color: #2ea44f;
    --text-color: #24292e;
    --light-text: #586069;
    --background: #ffffff;
    --section-bg: #f6f8fa;
    --border-color: #e1e4e8;
    --timeline-dot: #0366d6;
    --timeline-line: #e1e4e8;
    --skill-bg: #f1f8ff;
}

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

body {
    font-family: 'Roboto', sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--background);
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 20px;
}

a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color 0.3s ease;
}

a:hover {
    text-decoration: underline;
}

/* Header Styles */
header {
    background: linear-gradient(135deg, #0366d6, #2ea44f);
    color: white;
    padding: 80px 0;
    text-align: center;
}

.profile {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.profile-image {
    margin-bottom: 20px;
}

.avatar {
    width: 150px;
    height: 150px;
    border-radius: 50%;
    border: 4px solid white;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.2);
}

.profile-content h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
}

.subtitle {
    font-size: 1.2rem;
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: 20px;
}

.social-links {
    display: flex;
    gap: 15px;
    margin-top: 20px;
}

.social-links a {
    color: white;
    font-size: 1.5rem;
    transition: transform 0.3s ease;
}

.social-links a:hover {
    transform: translateY(-3px);
    text-decoration: none;
}

/* Section Styles */
.section {
    padding: 60px 0;
    border-bottom: 1px solid var(--border-color);
}

.section:nth-child(even) {
    background-color: var(--section-bg);
}

.section-title {
    font-size: 2rem;
    margin-bottom: 30px;
    text-align: center;
    position: relative;
}

.section-title::after {
    content: '';
    display: block;
    width: 50px;
    height: 3px;
    background-color: var(--primary-color);
    margin: 10px auto 0;
}

/* Timeline Styles */
.timeline-item {
    display: flex;
    margin-bottom: 40px;
    position: relative;
}

.timeline-date {
    flex: 0 0 150px;
    font-weight: 500;
    position: relative;
    padding-right: 20px;
}

.timeline-date span {
    background-color: var(--primary-color);
    color: white;
    padding: 5px 10px;
    border-radius: 4px;
    display: inline-block;
}

.timeline-content {
    flex: 1;
    padding-left: 30px;
    position: relative;
    border-left: 2px solid var(--timeline-line);
}

.timeline-content::before {
    content: '';
    position: absolute;
    width: 12px;
    height: 12px;
    background-color: var(--timeline-dot);
    border-radius: 50%;
    left: -7px;
    top: 6px;
}

.timeline-content h3 {
    font-size: 1.3rem;
    margin-bottom: 5px;
    color: var(--primary-color);
}

.timeline-content p {
    margin-bottom: 10px;
}

.timeline-content .subtitle {
    color: var(--light-text);
    font-size: 1rem;
    margin-bottom: 10px;
}

.timeline-content ul {
    margin: 10px 0 10px 20px;
}

/* Skills Styles */
.skills-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.skill-category {
    margin-bottom: 20px;
}

.skill-category h3 {
    font-size: 1.3rem;
    margin-bottom: 15px;
    color: var(--primary-color);
}

/* Research paper styles */
.paper-overview {
    background-color: #f8f9fa;
    border-left: 3px solid var(--primary-color);
    padding: 15px;
    margin: 15px 0;
    border-radius: 0 5px 5px 0;
}

.paper-overview ul {
    margin-left: 20px;
    margin-bottom: 15px;
}

.timeline-content .authors {
    font-style: italic;
}

.timeline-content sup {
    font-size: 0.7em;
    line-height: 0;
    position: relative;
    vertical-align: super;
}

.skill-items {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.skill-item {
    background-color: var(--skill-bg);
    color: var(--primary-color);
    padding: 5px 12px;
    border-radius: 15px;
    font-size: 0.9rem;
    border: 1px solid var(--primary-color);
}

/* Interest items styles */
.interests {
    margin-top: 30px;
}

.interests h3 {
    margin-bottom: 15px;
    font-size: 1.3rem;
}

.interest-items {
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
}

.interest-item {
    background-color: #f1f8ff;
    color: var(--primary-color);
    padding: 8px 15px;
    border-radius: 20px;
    font-size: 1rem;
    border: 1px solid var(--primary-color);
    display: inline-flex;
    align-items: center;
    transition: transform 0.3s ease;
}

.interest-item:hover {
    transform: translateY(-3px);
}

.interest-item i {
    margin-right: 8px;
}

/* Highlight style */
.highlight {
    background-color: #ffff99;
    padding: 2px 5px;
    border-radius: 3px;
    font-weight: bold;
}

/* Footer Styles */
footer {
    background-color: var(--section-bg);
    text-align: center;
    padding: 30px 0;
    color: var(--light-text);
    font-size: 0.9rem;
}

/* Responsive Styles */
@media (max-width: 768px) {
    .timeline-item {
        flex-direction: column;
    }
    
    .timeline-date {
        margin-bottom: 10px;
        padding-right: 0;
    }
    
    .timeline-content {
        padding-left: 20px;
    }
    
    .skills-container {
        grid-template-columns: 1fr;
    }
}