:root {
    --bg-dark: #0f172a;       /* Deep Navy/Black */
    --bg-card: #1e293b;       /* Lighter Navy for cards */
    --text-main: #e2e8f0;     /* Off-white text */
    --text-muted: #94a3b8;    /* Muted blue-grey text */
    --accent: #38bdf8;        /* Cyan/Light Blue Accent */
    --accent-hover: #0ea5e9;  /* Darker Blue Accent */
    --border: #334155;        /* Border color */
}

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

body {
    font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-dark);
    color: var(--text-main);
    line-height: 1.6;
}


header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem 5%;
    background-color: var(--bg-dark);
    border-bottom: 1px solid var(--border);
}

.logo {
    height: 70px;
    width: auto;
    filter: invert(1) brightness(2); 
}

.social-links a {
    color: var(--text-muted);
    font-size: 1.5rem;
    margin-left: 1.5rem;
    transition: color 0.3s ease;
}

.social-links a:hover {
    color: var(--accent);
}

.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 2rem;
}

h1 {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: white;
}

h2 {
    font-size: 1.5rem;
    color: var(--accent);
    font-weight: 400;
    margin-bottom: 1.5rem;
    text-transform: uppercase;
    letter-spacing: 1px;
}

h3 {
    font-size: 1.8rem;
    color: white;
    margin-bottom: 1.5rem;
    border-left: 4px solid var(--accent);
    padding-left: 15px;
}

.hero {
    margin: 3rem 0 4rem 0;
}

.summary {
    font-size: 1.15rem;
    color: var(--text-muted);
    max-width: 800px;
}

.publication-section {
    background: linear-gradient(145deg, var(--bg-card), #162032);
    padding: 1.5rem;
    border-radius: 12px;
    border: 1px solid var(--border);
    margin-bottom: 4rem;
    display: flex;
    gap: 1.5rem;
    align-items: flex-start;
}

.pub-icon {
    font-size: 2rem;
    color: var(--accent);
    background: rgba(56, 189, 248, 0.1);
    padding: 1rem;
    border-radius: 25%;
}

.pub-content h3 {
    border: none;
    padding: 0;
    margin-bottom: 0.5rem;
    font-size: 1.2rem;
    text-transform: uppercase;
    color: var(--text-muted);
    letter-spacing: 1px;
}

.pub-content h4 {
    font-size: 1.4rem;
    margin-bottom: 0.5rem;
    color: white;
}

.pub-publisher {
    color: var(--accent);
    margin-bottom: 1rem;
}

.pub-desc {
    color: var(--text-muted);
}

.skills-section {
    margin-bottom: 4rem;
}

.skills-wrapper {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
}

.skill-category {
    background-color: var(--bg-card);
    padding: 1.5rem;
    border-radius: 8px;
    border: 1px solid var(--border);
}

.skill-category h4 {
    color: white;
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 10px;
}

.skill-category h4 i {
    color: var(--accent);
}

.skill-category ul {
    list-style: none;
    padding: 0;
}

.skill-category li {
    color: var(--text-muted);
    margin-bottom: 0.5rem;
    padding-left: 1rem;
    border-left: 2px solid var(--border);
}

.certifications {
    margin-bottom: 4rem;
}

.cert-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
    gap: 1.5rem;
}

.cert-card {
    background-color: white; 
    padding: 1rem;
    border-radius: 8px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    transition: transform 0.2s ease;
    height: 180px;
}

.cert-card:hover {
    transform: translateY(-5px);
}

.cert-card img {
    max-width: 100%;
    max-height: 100px;
    object-fit: contain;
    margin-bottom: 10px;
}

.cert-card span {
    color: #333; 
    font-weight: bold;
    font-size: 0.85rem;
    text-align: center;
}


.timeline-item {
    display: flex;
    margin-bottom: 2rem;
    gap: 2rem;
}

.timeline-date {
    min-width: 150px;
    text-align: right;
    color: var(--accent);
    font-weight: bold;
    font-size: 0.95rem;
    padding-top: 5px;
}

.timeline-content {
    border-left: 2px solid var(--border);
    padding-left: 2rem;
    padding-bottom: 1rem;
}

.timeline-content h4 {
    font-size: 1.2rem;
    color: white;
    margin-bottom: 0.2rem;
}

.org {
    display: block;
    color: var(--text-muted);
    font-style: italic;
    margin-bottom: 0.8rem;
}

.award {
    margin-top: 0.5rem;
    color: #fbbf24; 
    font-weight: bold;
}


@media (max-width: 768px) {
    header {
        flex-direction: column;
        gap: 1rem;
    }
    
    .timeline-item {
        flex-direction: column;
        gap: 0.5rem;
    }
    
    .timeline-date {
        text-align: left;
        min-width: auto;
    }
    
    .timeline-content {
        border-left: none;
        padding-left: 0;
        border-top: 1px solid var(--border);
        padding-top: 1rem;
    }
}