/* VARIABLES & THEME */
:root {
    /* Light Theme (Default) */
    --bg-body: #ffffff;
    --bg-alt: #f8f9fa;
    --text-main: #1f2937;
    --text-muted: #6b7280;
    --primary: #0f766e; /* Teal-700 */
    --primary-hover: #115e59;
    --border: #e5e7eb;
    --card-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --font-heading: 'Inter', system-ui, -apple-system, sans-serif;
    --font-body: 'Inter', system-ui, -apple-system, sans-serif;
}

[data-theme="dark"] {
    --bg-body: #111827;
    --bg-alt: #1f2937;
    --text-main: #f9fafb;
    --text-muted: #9ca3af;
    --primary: #2dd4bf; /* Teal-400 */
    --primary-hover: #5eead4;
    --border: #374151;
    --card-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.5);
}

/* RESET & BASE */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-body);
    background-color: var(--bg-body);
    color: var(--text-main);
    line-height: 1.6;
    transition: background-color 0.3s ease, color 0.3s ease;
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 700;
    margin-bottom: 0.75rem;
    line-height: 1.2;
}

a {
    text-decoration: none;
    color: inherit;
    transition: color 0.2s ease;
}

ul {
    list-style: none;
}

img {
    max-width: 100%;
    display: block;
}

/* UTILITIES */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

.section {
    padding: 5rem 0;
}

.section-title {
    font-size: 2rem;
    text-align: center;
    margin-bottom: 3rem;
    position: relative;
    display: inline-block;
    left: 50%;
    transform: translateX(-50%);
}

.section-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 4px;
    background: var(--primary);
    margin: 0.5rem auto 0;
    border-radius: 2px;
}

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

.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: 6px;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease, opacity 0.2s ease;
}

.btn:active {
    transform: translateY(1px);
}

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

.btn-primary:hover {
    background-color: var(--primary-hover);
    box-shadow: 0 4px 12px rgba(15, 118, 110, 0.2);
}

.btn-secondary {
    background-color: transparent;
    border: 2px solid var(--text-main);
    color: var(--text-main);
}

.btn-secondary:hover {
    background-color: var(--text-main);
    color: var(--bg-body);
}

.btn-outline {
    border: 1px solid var(--border);
    color: var(--text-muted);
}

.btn-outline:hover {
    border-color: var(--primary);
    color: var(--primary);
}

/* NAVBAR */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background-color: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border);
    z-index: 1000;
    height: 70px;
    display: flex;
    align-items: center;
    transition: background-color 0.3s ease;
}

[data-theme="dark"] .navbar {
    background-color: rgba(17, 24, 39, 0.9);
}

.nav-container {
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-main);
}

.nav-links {
    display: flex;
    gap: 2rem;
}

.nav-links a {
    font-weight: 500;
    color: var(--text-muted);
    font-size: 0.95rem;
}

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

.nav-utilities {
    display: flex;
    align-items: center;
    gap: 1rem;
}

#theme-toggle {
    background: none;
    border: none;
    cursor: pointer;
    color: var(--text-muted);
    padding: 0.5rem;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background-color 0.2s ease;
}

#theme-toggle:hover {
    background-color: var(--bg-alt);
    color: var(--primary);
}

.sun-icon { display: block; }
.moon-icon { display: none; }

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

.mobile-menu-btn {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
}

.mobile-menu-btn span {
    display: block;
    width: 25px;
    height: 3px;
    background-color: var(--text-main);
    border-radius: 2px;
}

/* HERO SECTION */
.hero-section {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding-top: 70px; /* Offset for navbar */
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.eyebrow {
    color: var(--primary);
    font-weight: 600;
    text-transform: uppercase;
    font-size: 0.9rem;
    letter-spacing: 1px;
    margin-bottom: 0.5rem;
    display: block;
}

.hero-text h1 {
    font-size: 3.5rem;
    margin-bottom: 1.5rem;
    color: var(--text-main);
}

.hero-text .subtitle {
    font-size: 1.25rem;
    color: var(--text-muted);
    margin-bottom: 2.5rem;
    max-width: 500px;
}

.cta-group {
    display: flex;
    gap: 1rem;
}

.hero-image {
    display: flex;
    justify-content: center;
}

.img-placeholder {
    width: 350px;
    height: 350px;
    background-color: var(--bg-alt);
    border: 2px dashed var(--border);
    border-radius: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-muted);
    font-weight: 500;
}

/* ABOUT SECTION */
.about-content {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
    font-size: 1.1rem;
    color: var(--text-muted);
}

.about-content p {
    margin-bottom: 1.5rem;
}

/* SKILLS SECTION */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.skill-card {
    background: var(--bg-body);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--card-shadow);
    border: 1px solid var(--border);
}

.skill-card h3 {
    color: var(--primary);
    margin-bottom: 1.5rem;
    font-size: 1.2rem;
}

.skill-list li {
    margin-bottom: 0.75rem;
    padding-left: 1.5rem;
    position: relative;
    color: var(--text-main);
}

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

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

.project-card {
    background: var(--bg-body);
    border: 1px solid var(--border);
    border-radius: 12px;
    overflow: hidden;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.project-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--card-shadow);
}

.project-content {
    padding: 2rem;
}

.project-tag {
    display: inline-block;
    font-size: 0.75rem;
    background-color: var(--bg-alt);
    color: var(--primary);
    padding: 0.25rem 0.75rem;
    border-radius: 50px;
    margin-bottom: 1rem;
    font-weight: 600;
    text-transform: uppercase;
}

.project-content h3 {
    margin-bottom: 1rem;
    font-size: 1.5rem;
}

.project-content p {
    color: var(--text-muted);
    margin-bottom: 1.5rem;
    font-size: 1rem;
}

.project-metrics {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    margin-bottom: 1.5rem;
    padding-top: 1rem;
    border-top: 1px solid var(--border);
}

.project-metrics span {
    font-size: 0.9rem;
    color: var(--text-main);
    display: flex;
    flex-direction: column;
}

.project-metrics .metric {
    font-size: 1.1rem;
    color: var(--primary);
}

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

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

/* EXPERIENCE SECTION */
.timeline {
    max-width: 800px;
    margin: 0 auto;
    position: relative;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    height: 100%;
    width: 2px;
    background-color: var(--border);
}

.timeline-item {
    position: relative;
    padding-left: 2rem;
    margin-bottom: 3rem;
}

.timeline-marker {
    position: absolute;
    left: -4px;
    top: 5px;
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background-color: var(--primary);
    border: 2px solid var(--bg-alt);
}

.timeline-header {
    margin-bottom: 0.5rem;
}

.timeline-header h3 {
    margin-bottom: 0.25rem;
    font-size: 1.25rem;
}

.company {
    font-weight: 600;
    color: var(--text-main);
}

.date {
    display: block;
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-top: 0.25rem;
}

.job-highlights {
    margin-top: 1rem;
    list-style-type: disc;
    padding-left: 1.2rem;
    color: var(--text-muted);
}

.job-highlights li {
    margin-bottom: 0.5rem;
}

/* EDUCATION SECTION */
.education-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    text-align: center;
}

.edu-card {
    padding: 2rem;
    background: var(--bg-alt);
    border-radius: 12px;
}

.edu-card h3 {
    font-size: 1.2rem;
    margin-bottom: 0.5rem;
}

.edu-card .institution {
    font-weight: 600;
    color: var(--primary);
    display: block;
    margin-bottom: 0.5rem;
}

.edu-card .edu-detail {
    font-size: 0.9rem;
    color: var(--text-muted);
}

/* CONTACT SECTION */
.contact-section {
    text-align: center;
}

.contact-text {
    font-size: 1.25rem;
    color: var(--text-muted);
    margin-bottom: 2.5rem;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.contact-actions {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
}

/* FOOTER */
.footer {
    background-color: var(--bg-alt);
    padding: 2rem 0;
    text-align: center;
    border-top: 1px solid var(--border);
    color: var(--text-muted);
    font-size: 0.9rem;
}

/* RESPONSIVE */
@media (max-width: 768px) {
    .nav-links {
        display: none; /* In production: add JS mobile toggle logic */
    }
    
    .mobile-menu-btn {
        display: flex;
    }

    /* Simple Mobile Menu Override for No-JS fallback or simple implementation */
    .nav-links.active {
        display: flex;
        flex-direction: column;
        position: absolute;
        top: 70px;
        left: 0;
        width: 100%;
        background-color: var(--bg-body);
        padding: 2rem;
        border-bottom: 1px solid var(--border);
        box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    }

    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 2rem;
    }
    
    .hero-text h1 {
        font-size: 2.5rem;
    }

    .hero-text .subtitle {
        margin: 0 auto 2rem;
    }

    .cta-group {
        justify-content: center;
    }

    .timeline::before {
        left: 20px;
    }
    
    .timeline-item {
        padding-left: 3rem;
    }
    
    .timeline-marker {
        left: 16px;
    }
}