/* 1. Global Reset & Variables */
:root {
    --bg-color: #121212; /* Dark background */
    --text-color: #e0e0e0; /* Light text */
    --primary-color: #64ffda; /* Neon/Accent Color */
    --secondary-bg: #1e1e1e; /* Slightly lighter dark for cards */
    --font-family: 'Inter', sans-serif;
    --max-width: 900px;
}

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

body {
    font-family: var(--font-family);
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
}

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 20px;
}

/* 2. Typography & Links */
h1, h2, h3 {
    color: var(--text-color);
    margin-bottom: 0.5em;
}

h1 { font-size: 2.5em; }
h2 { 
    font-size: 1.8em; 
    border-bottom: 2px solid var(--secondary-bg);
    padding-bottom: 5px;
    margin-top: 1.5em;
    margin-bottom: 1em;
}
h3 { font-size: 1.2em; }

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

a:hover {
    color: #a6ffec; /* Lighter shade on hover */
    text-decoration: underline;
}

/* 3. Header/Hero Styling */
header {
    background-color: var(--secondary-bg);
    padding: 40px 0;
    text-align: center;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

.name { margin-bottom: 5px; font-weight: 700; }
.tagline {
    font-size: 1.1em;
    font-weight: 300;
    color: #cccccc;
    margin-bottom: 20px;
}

.contact-links a {
    margin: 0 10px;
    font-weight: 400;
    letter-spacing: 0.5px;
}

.status {
    margin-top: 20px;
    font-style: italic;
    color: var(--primary-color);
    font-size: 0.9em;
}

/* 4. Section Styling & Divider */
section {
    padding: 20px 0;
}

hr {
    border: none;
    height: 1px;
    background-color: var(--secondary-bg);
    margin: 30px 0;
}

/* 5. About Section (Skills Grid) */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-top: 20px;
}

.skills-grid div {
    background-color: var(--secondary-bg);
    padding: 20px;
    border-radius: 5px;
    border-left: 3px solid var(--primary-color);
}

.skills-grid h3 {
    margin-top: 0;
    color: var(--primary-color);
}

/* 6. Projects Section - Filter Buttons */
.filter-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 25px;
}

.filter-btn {
    padding: 8px 15px;
    border: 1px solid var(--primary-color);
    background-color: var(--bg-color);
    color: var(--primary-color);
    cursor: pointer;
    border-radius: 5px;
    transition: all 0.2s ease;
    font-size: 0.9em;
}

.filter-btn:hover {
    background-color: rgba(100, 255, 218, 0.1);
}

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

.project-list {
    display: grid;
    grid-template-columns: 1fr;
    gap: 25px;
}

.project-card {
    background-color: var(--secondary-bg);
    padding: 20px;
    border-radius: 5px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    transition: transform 0.2s, opacity 0.3s;
}

.project-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
}

.project-card h3 {
    margin-bottom: 5px;
}

.project-card p {
    font-size: 0.9em;
    color: #aaaaaa;
    margin-bottom: 10px;
}

.language {
    display: inline-block;
    background-color: rgba(100, 255, 218, 0.2);
    color: var(--primary-color);
    padding: 3px 8px;
    border-radius: 3px;
    font-size: 0.75em;
    font-weight: 700;
    margin-right: 8px;
    margin-top: 5px;
}

.archive-link {
    text-align: right;
    margin-top: 20px;
    font-size: 0.9em;
}

/* 7. Publications Section */
.publication-list p {
    margin-bottom: 10px;
    font-size: 0.95em;
    color: #cccccc;
}

/* 8. Footer Styling */
footer {
    text-align: center;
    padding: 20px 0;
    font-size: 0.8em;
    color: #666666;
    border-top: 1px solid var(--secondary-bg);
    margin-top: 40px;
}

/* 9. Responsiveness */
@media (max-width: 600px) {
    h1 { font-size: 2em; }
    h2 { font-size: 1.5em; }
    .skills-grid {
        grid-template-columns: 1fr;
    }
}