/* ===================================
   Modern Portfolio CSS with Dark/Light Theme
   =================================== */

/* CSS Custom Properties for Theming */
:root {
    /* Dark Theme (Default) */
    --bg-primary: #0a0a0a;
    --bg-secondary: #1a1a1a;
    --bg-tertiary: #2a2a2a;
    --text-primary: #e0e0e0;
    --text-secondary: #a0a0a0;
    --text-muted: #707070;
    --accent-primary: #3b82f6;
    --accent-secondary: #60a5fa;
    --accent-hover: #2563eb;
    --border-color: #333;
    --shadow: rgba(0, 0, 0, 0.3);
    --overlay: rgba(0, 0, 0, 0.7);
    --gradient-start: #1e3a8a;
    --gradient-end: #3b82f6;
}

[data-theme="light"] {
    --bg-primary: #ffffff;
    --bg-secondary: #f5f5f5;
    --bg-tertiary: #e5e5e5;
    --text-primary: #1a1a1a;
    --text-secondary: #4a4a4a;
    --text-muted: #8a8a8a;
    --accent-primary: #3b82f6;
    --accent-secondary: #2563eb;
    --accent-hover: #1d4ed8;
    --border-color: #ddd;
    --shadow: rgba(0, 0, 0, 0.1);
    --overlay: rgba(255, 255, 255, 0.9);
    --gradient-start: #3b82f6;
    --gradient-end: #60a5fa;
}

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: background-color 0.3s ease, color 0.3s ease;
    overflow-x: hidden;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 1rem;
}

h1 { font-size: 3rem; }
h2 { font-size: 2.5rem; }
h3 { font-size: 1.75rem; }
h4 { font-size: 1.5rem; }

p {
    margin-bottom: 1rem;
}

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

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

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* Navigation */
#nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background-color: var(--bg-secondary);
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 10px var(--shadow);
    z-index: 1000;
    transition: background-color 0.3s ease;
}

#nav .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
}

#nav .logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--accent-primary);
}

#nav .nav-links {
    display: flex;
    list-style: none;
    gap: 2rem;
}

#nav .nav-links a {
    color: var(--text-primary);
    font-weight: 500;
    transition: color 0.3s ease;
}

#nav .nav-links a:hover {
    color: var(--accent-primary);
}

/* Theme Toggle Button */
#theme-toggle {
    background: none;
    border: 2px solid var(--border-color);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
}

#theme-toggle:hover {
    border-color: var(--accent-primary);
    transform: rotate(20deg);
}

#theme-toggle svg {
    width: 20px;
    height: 20px;
    color: var(--text-primary);
}

[data-theme="dark"] .sun-icon {
    display: block;
}

[data-theme="dark"] .moon-icon {
    display: none;
}

[data-theme="light"] .sun-icon {
    display: none;
}

[data-theme="light"] .moon-icon {
    display: block;
}

/* Particle Canvas Background */
#particle-canvas {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    opacity: 0.3;
}

/* Hero Section */
#hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    padding-top: 80px;
    background: linear-gradient(135deg, var(--gradient-start) 0%, var(--gradient-end) 100%);
}

.hero-content {
    text-align: center;
    z-index: 1;
}

.hero-content h1 {
    font-size: 4rem;
    margin-bottom: 1rem;
    color: #fff;
}

.typing-container {
    height: 3rem;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1rem;
}

#typed-text {
    font-size: 2rem;
    color: #fff;
    font-weight: 500;
}

.cursor {
    display: inline-block;
    font-size: 2rem;
    color: #fff;
    animation: blink 1s infinite;
    margin-left: 0.2rem;
}

@keyframes blink {
    0%, 50% { opacity: 1; }
    51%, 100% { opacity: 0; }
}

.subtitle {
    font-size: 1.2rem;
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: 2rem;
}

.hero-cta {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

/* Fade-in Animations */
.fade-in {
    animation: fadeIn 1s ease-in;
}

.fade-in-delay {
    animation: fadeIn 1s ease-in 0.3s both;
}

.fade-in-delay-2 {
    animation: fadeIn 1s ease-in 0.6s both;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 2rem;
    border-radius: 8px;
    font-weight: 600;
    font-size: 1rem;
    transition: all 0.3s ease;
    cursor: pointer;
    border: none;
}

.btn-primary {
    background-color: var(--accent-primary);
    color: #fff;
}

.btn-primary:hover {
    background-color: var(--accent-hover);
    transform: translateY(-2px);
    box-shadow: 0 5px 15px var(--shadow);
}

.btn-secondary {
    background-color: transparent;
    color: #fff;
    border: 2px solid #fff;
}

.btn-secondary:hover {
    background-color: #fff;
    color: var(--accent-primary);
}

.btn-outline {
    background-color: transparent;
    color: var(--accent-primary);
    border: 2px solid var(--accent-primary);
}

.btn-outline:hover {
    background-color: var(--accent-primary);
    color: #fff;
}

.btn-small {
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

/* Wrapper Sections */
.wrapper {
    padding: 5rem 0;
}

.wrapper.style-alt {
    background-color: var(--bg-secondary);
}

/* Section Headers */
.section-header {
    text-align: center;
    margin-bottom: 4rem;
}

.section-header h2 {
    margin-bottom: 0.5rem;
}

.section-header p {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

/* About Section */
.about-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 3rem;
    align-items: center;
}

.about-text h2 {
    margin-bottom: 1.5rem;
}

.profile-img {
    width: 100%;
    border-radius: 16px;
    box-shadow: 0 10px 30px var(--shadow);
}

/* Projects Grid */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

/* Employment Section */
.employment-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2rem;
}

.employment-card {
    background-color: var(--bg-tertiary);
    border-radius: 12px;
    padding: 1.5rem;
    display: grid;
    grid-template-columns: 120px 1fr;
    gap: 1.5rem;
    align-items: center;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.employment-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 12px 30px var(--shadow);
}

.employment-logo img {
    max-width: 100%;
    max-height: 80px;
    object-fit: contain;
    filter: drop-shadow(0 4px 10px var(--shadow));
}

.employment-content h3 {
    margin-bottom: 0.5rem;
}

.employment-content p {
    color: var(--text-secondary);
    margin-bottom: 0.75rem;
}

.employment-links {
    display: flex;
    gap: 0.75rem;
    flex-wrap: wrap;
}

.project-card {
    background-color: var(--bg-tertiary);
    border-radius: 12px;
    overflow: hidden;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    cursor: pointer;
}

.project-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 40px var(--shadow);
}

.project-image {
    position: relative;
    height: 220px;
    overflow: hidden;
}

.project-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.3s ease;
}

.project-card:hover .project-image img {
    transform: scale(1.1);
}

.project-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: var(--overlay);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.project-card:hover .project-overlay {
    opacity: 1;
}

.project-link {
    color: #fff;
    font-weight: 600;
    font-size: 1.1rem;
    padding: 0.75rem 1.5rem;
    border: 2px solid #fff;
    border-radius: 8px;
    transition: all 0.3s ease;
}

.project-link:hover {
    background-color: #fff;
    color: var(--bg-primary);
}

.project-content {
    padding: 1.5rem;
}

.project-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.tag {
    background-color: var(--accent-primary);
    color: #fff;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
}

.project-content h3 {
    margin-bottom: 0.75rem;
}

.project-content p {
    color: var(--text-secondary);
    margin-bottom: 1rem;
    font-size: 0.95rem;
}

.project-links {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.icon-link {
    color: var(--accent-primary);
    font-weight: 500;
    font-size: 0.9rem;
    transition: color 0.3s ease;
}

.icon-link:hover {
    color: var(--accent-hover);
}

.more-projects {
    text-align: center;
}

/* Publications Section */
.publications-list {
    display: flex;
    flex-direction: column;
    gap: 2rem;
    margin-bottom: 3rem;
}

.publication-card {
    background-color: var(--bg-tertiary);
    border-radius: 12px;
    padding: 2rem;
    display: grid;
    grid-template-columns: 150px 1fr;
    gap: 2rem;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.publication-card:hover {
    transform: translateX(10px);
    box-shadow: 0 10px 30px var(--shadow);
}

.publication-meta {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.publication-year {
    font-size: 2rem;
    font-weight: 700;
    color: var(--accent-primary);
}

.publication-type {
    font-size: 0.85rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.publication-content h3 {
    margin-bottom: 0.75rem;
    font-size: 1.3rem;
}

.publication-authors {
    color: var(--text-secondary);
    font-style: italic;
    margin-bottom: 0.5rem;
}

.publication-venue {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

.publication-abstract {
    color: var(--text-secondary);
    margin-bottom: 1rem;
    line-height: 1.8;
}

.publication-links {
    display: flex;
    gap: 0.75rem;
    flex-wrap: wrap;
}

.researchgate-link {
    text-align: center;
}

/* Currently Working Section */
.refresh-btn {
    background: none;
    border: 2px solid var(--border-color);
    border-radius: 50%;
    width: 36px;
    height: 36px;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    margin-left: 1rem;
    transition: all 0.3s ease;
}

.refresh-btn:hover {
    border-color: var(--accent-primary);
    transform: rotate(180deg);
}

.refresh-btn svg {
    width: 18px;
    height: 18px;
    color: var(--text-primary);
}

.activity-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2rem;
}

.activity-card {
    background-color: var(--bg-tertiary);
    border-radius: 12px;
    padding: 1.5rem;
    transition: transform 0.3s ease;
}

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

.activity-card h3 {
    margin-bottom: 0.5rem;
    font-size: 1.3rem;
}

.activity-card h3 a {
    color: var(--text-primary);
}

.language-badge {
    display: inline-block;
    background-color: var(--accent-primary);
    color: #fff;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.8rem;
    margin-bottom: 0.75rem;
}

.last-updated {
    color: var(--text-muted);
    font-size: 0.85rem;
    margin-bottom: 0.75rem;
}

.description {
    color: var(--text-secondary);
    margin-bottom: 0.75rem;
}

.commit-preview {
    color: var(--text-muted);
    font-style: italic;
    font-size: 0.9rem;
}

.activity-timestamp {
    text-align: center;
    color: var(--text-muted);
    font-size: 0.85rem;
    margin-top: 2rem;
}

/* Skeleton Loading */
.activity-skeleton {
    display: contents;
}

.skeleton-card {
    background: linear-gradient(90deg, var(--bg-tertiary) 25%, var(--bg-secondary) 50%, var(--bg-tertiary) 75%);
    background-size: 200% 100%;
    animation: loading 1.5s infinite;
    border-radius: 12px;
    height: 200px;
}

@keyframes loading {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}

/* Skills Section */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.skill-category {
    background-color: var(--bg-tertiary);
    border-radius: 12px;
    padding: 2rem;
    transition: transform 0.3s ease;
}

.skill-category:hover {
    transform: translateY(-5px);
}

.skill-category h3 {
    margin-bottom: 1.5rem;
    color: var(--accent-primary);
}

.skill-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
}

.skill-tag {
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    padding: 0.5rem 1rem;
    border-radius: 8px;
    font-size: 0.9rem;
    transition: all 0.3s ease;
}

.skill-tag:hover {
    background-color: var(--accent-primary);
    color: #fff;
    transform: translateY(-2px);
}

/* Contact Section */
.contact-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 4rem;
}

#contact-form {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 1rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    background-color: var(--bg-tertiary);
    color: var(--text-primary);
    font-size: 1rem;
    font-family: inherit;
    transition: border-color 0.3s ease;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--accent-primary);
}

.form-group textarea {
    resize: vertical;
    min-height: 150px;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.contact-item h4 {
    color: var(--accent-primary);
    margin-bottom: 0.5rem;
}

.contact-item a {
    color: var(--text-secondary);
}

/* Footer */
footer {
    background-color: var(--bg-secondary);
    padding: 3rem 0;
    text-align: center;
    border-top: 1px solid var(--border-color);
}

footer p {
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.footer-links a {
    color: var(--text-secondary);
    margin: 0 0.5rem;
}

/* Scroll Animations */
[data-aos="fade-up"] {
    opacity: 0;
    transform: translateY(50px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

[data-aos="fade-up"].aos-animate {
    opacity: 1;
    transform: translateY(0);
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 0 1rem;
    }

    #nav .nav-links {
        display: none; /* Mobile menu would need JavaScript */
    }

    .hero-content h1 {
        font-size: 2.5rem;
    }

    #typed-text {
        font-size: 1.5rem;
    }

    .about-content {
        grid-template-columns: 1fr;
    }

    .projects-grid {
        grid-template-columns: 1fr;
    }

    .publication-card {
        grid-template-columns: 1fr;
    }

    .contact-content {
        grid-template-columns: 1fr;
    }

    .form-row {
        grid-template-columns: 1fr;
    }

    h1 { font-size: 2rem; }
    h2 { font-size: 1.75rem; }
}

@media (max-width: 480px) {
    .hero-content h1 {
        font-size: 2rem;
    }

    #typed-text {
        font-size: 1.2rem;
    }

    .btn {
        padding: 0.6rem 1.5rem;
        font-size: 0.9rem;
    }
}