@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600&family=Outfit:wght@400;600;700&display=swap');

:root {
    --bg-dark: #05070a;
    --bg-card: rgba(17, 25, 40, 0.75);
    --bg-accent: rgba(25, 40, 60, 0.4);

    --text-primary: #f8fafc;
    --text-secondary: #cbd5e1;
    --text-dim: #94a3b8;

    --accent: #38bdf8;
    --accent-glow: rgba(56, 189, 248, 0.3);
    --accent-dark: #0ea5e9;
    --accent-2: #818cf8;

    --green: #34d399;
    --green-glow: rgba(52, 211, 153, 0.15);
    --green-border: rgba(52, 211, 153, 0.35);

    --border: rgba(255, 255, 255, 0.08);
    --border-hover: rgba(56, 189, 248, 0.4);

    --glass-blur: 16px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --radius: 16px;
}

*,
*::before,
*::after {
    box-sizing: border-box;
}

* {
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    scroll-padding-top: 5rem;
}

body {
    background-color: var(--bg-dark);
    color: var(--text-primary);
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
}

/* ─── Navigation ─── */
.main-nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.7rem 2rem;
    background: rgba(5, 7, 10, 0.8);
    backdrop-filter: blur(var(--glass-blur));
    border-bottom: 1px solid var(--border);
}

.nav-logo {
    display: flex;
    align-items: center;
    text-decoration: none;
}

.nav-logo img {
    height: 2.6rem;
    width: auto;
}

.nav-links {
    display: flex;
    gap: 0.25rem;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    padding: 0.4rem 0.9rem;
    border-radius: 8px;
    transition: var(--transition);
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--text-primary);
    background: var(--bg-accent);
}

.nav-actions {
    display: flex;
    gap: 0.35rem;
    background: var(--bg-card);
    padding: 0.3rem;
    border-radius: 99px;
    border: 1px solid var(--border);
}

.lang-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    padding: 0.3rem 0.7rem;
    border-radius: 99px;
    cursor: pointer;
    font-weight: 600;
    font-size: 0.8rem;
    transition: var(--transition);
}

.lang-btn.active {
    background: var(--accent);
    color: var(--bg-dark);
}

.lang-btn:hover:not(.active) {
    color: var(--text-primary);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}

.nav-toggle span {
    display: block;
    width: 22px;
    height: 2px;
    background: var(--text-secondary);
    border-radius: 2px;
    transition: var(--transition);
}

/* ─── Hero ─── */
.hero {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    padding: 8rem 1.5rem 4rem;
    position: relative;
    overflow: hidden;
}

.profile-photo {
    width: 130px;
    height: 130px;
    border-radius: 50%;
    object-fit: cover;
    border: 3px solid var(--border);
    margin-bottom: 2rem;
    transition: var(--transition);
    filter: grayscale(0.15);
    position: relative;
    z-index: 1;
}

.profile-photo:hover {
    filter: grayscale(0);
}

.hero h1 {
    font-family: 'Outfit', sans-serif;
    font-size: 3.8rem;
    font-weight: 500;
    letter-spacing: 0;
    position: relative;
    z-index: 1;
    color: var(--text-primary);
}

.hero .tagline {
    font-size: 1.15rem;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 1.5rem auto 0;
    position: relative;
    z-index: 1;
    line-height: 1.5;
}

.hero-degree {
    display: inline-block;
    font-size: 0.95rem;
    color: var(--text-dim);
    margin-top: 0.5rem;
}

.hero-degree-sub {
    display: inline-block;
    font-size: 0.85rem;
    color: var(--text-dim);
    margin-top: 0.25rem;
}

.profile-links {
    display: flex;
    justify-content: center;
    gap: 0.75rem;
    margin-top: 2.5rem;
    position: relative;
    z-index: 1;
}

.profile-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.9rem;
    padding: 0.5rem 1rem;
    border-radius: 10px;
    border: 1px solid var(--border);
    transition: var(--transition);
}

.profile-links a:hover {
    color: var(--accent);
    border-color: var(--border-hover);
    background: var(--bg-accent);
    transform: translateY(-2px);
}

/* ─── Content Container ─── */
.content {
    max-width: 820px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* ─── Sections ─── */
section {
    padding: 5rem 0;
}

section h2 {
    font-family: 'Outfit', sans-serif;
    font-size: 1.6rem;
    margin-bottom: 2.5rem;
    display: flex;
    align-items: center;
    gap: 1rem;
}

section h2::after {
    content: "";
    height: 1px;
    flex-grow: 1;
    background: linear-gradient(to right, var(--border), transparent);
}

/* ─── About ─── */
.about-text {
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
}

.about-text p {
    color: var(--text-secondary);
    font-size: 1.05rem;
    line-height: 1.8;
}

.about-text strong {
    color: var(--text-primary);
    font-weight: 600;
}

/* ─── Projects Grid ─── */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
}

.project-card {
    background: var(--bg-card);
    backdrop-filter: blur(var(--glass-blur));
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 2rem;
    transition: var(--transition);
    display: flex;
    flex-direction: column;
    cursor: pointer;
    text-decoration: none;
    color: inherit;
}

.project-card:hover {
    transform: translateY(-6px);
    border-color: var(--border-hover);
    box-shadow: 0 16px 40px rgba(0, 0, 0, 0.35);
}

.project-tag {
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--accent);
    margin-bottom: 0.75rem;
}

.project-card h3 {
    font-family: 'Outfit', sans-serif;
    font-size: 1.3rem;
    margin-bottom: 0.75rem;
}

.project-card p {
    color: var(--text-secondary);
    font-size: 0.92rem;
    flex-grow: 1;
    margin-bottom: 1.5rem;
}

.project-arrow {
    color: var(--text-dim);
    font-size: 0.85rem;
    font-weight: 500;
    transition: var(--transition);
}

.project-card:hover .project-arrow {
    color: var(--accent);
    transform: translateX(4px);
}

/* ─── Skills ─── */
.skills-container {
    display: flex;
    flex-direction: column;
    gap: 2.5rem;
}

.skills-category h3 {
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-dim);
    margin-bottom: 1.25rem;
}

.skill-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.6rem;
    list-style: none;
}

.skill-tags li {
    background: var(--bg-accent);
    border: 1px solid var(--border);
    padding: 0.45rem 0.9rem;
    border-radius: 10px;
    font-size: 0.88rem;
    font-weight: 500;
    color: var(--text-primary);
    transition: var(--transition);
}

.skill-tags li:hover {
    border-color: var(--accent);
    transform: translateY(-2px);
}

/* ─── Certifications ─── */
.cert-list {
    display: grid;
    gap: 0.75rem;
}

.cert-item {
    background: var(--bg-card);
    border: 1px solid var(--border);
    padding: 1.1rem 1.25rem;
    border-radius: 12px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: var(--transition);
}

.cert-item:hover {
    border-color: var(--border-hover);
    background: var(--bg-accent);
}

.cert-info strong {
    display: block;
    color: var(--text-primary);
    font-size: 0.95rem;
}

.cert-info span {
    color: var(--text-secondary);
    font-size: 0.82rem;
    display: block;
}

.edu-university {
    font-size: 1.05rem;
    color: var(--text-primary);
    font-weight: 600;
    margin-bottom: 0.35rem;
    letter-spacing: -0.01em;
}

.edu-degree {
    font-size: 0.9rem;
    color: var(--text-secondary);
    display: block;
    margin-bottom: 0.2rem;
}

.edu-gpa {
    font-size: 0.82rem;
    color: var(--text-dim);
    display: block;
}

/* ─── Contact ─── */
.contact-section {
    text-align: center;
}

.contact-section p {
    color: var(--text-secondary);
    font-size: 1.05rem;
    max-width: 500px;
    margin: 0 auto 2.5rem;
}

.contact-cta {
    display: inline-flex;
    align-items: center;
    gap: 0.6rem;
    padding: 0.9rem 2rem;
    border-radius: 12px;
    font-weight: 600;
    font-size: 1rem;
    text-decoration: none;
    transition: var(--transition);
    background: var(--accent);
    color: var(--bg-dark);
    border: none;
    cursor: pointer;
}

.contact-cta:hover {
    background: #7dd3fc;
    transform: translateY(-2px);
}

.contact-alt {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    margin-top: 1.5rem;
}

.contact-alt a {
    color: var(--text-dim);
    text-decoration: none;
    font-size: 0.9rem;
    transition: var(--transition);
}

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

/* ─── Footer ─── */
footer {
    text-align: center;
    padding: 4rem 0 3rem;
    color: var(--text-dim);
    font-size: 0.85rem;
    border-top: 1px solid var(--border);
}

/* ─── Fade-in animations ─── */
.fade-in {
    opacity: 0;
    transform: translateY(25px);
    transition: opacity 0.7s ease, transform 0.7s ease;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ─── Project Detail Pages ─── */
.page-container {
    max-width: 780px;
    margin: 0 auto;
    padding: 7rem 1.5rem 4rem;
}

.back-link {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    color: var(--text-dim);
    text-decoration: none;
    font-size: 0.9rem;
    margin-bottom: 2rem;
    transition: var(--transition);
}

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

.page-header {
    margin-bottom: 3.5rem;
}

.page-header .project-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1.25rem;
}

.page-header .project-tags span {
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    padding: 0.3rem 0.75rem;
    border-radius: 8px;
    background: var(--bg-accent);
    border: 1px solid var(--border);
    color: var(--accent);
}

.page-header h1 {
    font-family: 'Outfit', sans-serif;
    font-size: 2.6rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    line-height: 1.2;
}

.page-header .subtitle {
    color: var(--text-secondary);
    font-size: 1.05rem;
    margin-top: 0.75rem;
}

.page-content section {
    padding: 2rem 0;
}

.page-content h2 {
    font-family: 'Outfit', sans-serif;
    font-size: 1.35rem;
    margin-bottom: 1.25rem;
}

.page-content p {
    color: var(--text-secondary);
    font-size: 1rem;
    line-height: 1.8;
    margin-bottom: 1rem;
}

.page-content ul {
    color: var(--text-secondary);
    padding-left: 1.5rem;
    margin-bottom: 1rem;
}

.page-content li {
    margin-bottom: 0.5rem;
    font-size: 0.95rem;
}

.page-cta {
    display: flex;
    gap: 1rem;
    margin-top: 3rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border);
}

.page-cta a {
    padding: 0.75rem 1.5rem;
    border-radius: 10px;
    text-decoration: none;
    font-weight: 600;
    font-size: 0.9rem;
    transition: var(--transition);
}

.page-cta .btn-primary {
    background: var(--accent);
    color: var(--bg-dark);
}

.page-cta .btn-primary:hover {
    background: #7dd3fc;
    transform: translateY(-2px);
}

.page-cta .btn-secondary {
    background: var(--bg-accent);
    color: var(--text-primary);
    border: 1px solid var(--border);
}

.page-cta .btn-secondary:hover {
    border-color: var(--border-hover);
    transform: translateY(-2px);
}

/* ─── Uses Page ─── */
.uses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.uses-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 2rem;
    transition: var(--transition);
}

.uses-card:hover {
    border-color: var(--border-hover);
}

.uses-card h3 {
    font-family: 'Outfit', sans-serif;
    font-size: 1.15rem;
    margin-bottom: 1.25rem;
    color: var(--accent);
}

.uses-item {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    padding: 0.6rem 0;
    border-bottom: 1px solid var(--border);
}

.uses-item:last-child {
    border-bottom: none;
}

.uses-item strong {
    color: var(--text-primary);
    font-size: 0.92rem;
    font-weight: 500;
}

.uses-item span {
    color: var(--text-dim);
    font-size: 0.85rem;
}

/* ─── Interactive Demo ─── */
.demo-container {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 2.5rem;
    margin-top: 2rem;
}

.demo-inputs {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.25rem;
    margin-bottom: 2rem;
}

.demo-field label {
    display: block;
    font-size: 0.8rem;
    color: var(--text-dim);
    text-transform: uppercase;
    letter-spacing: 0.06em;
    margin-bottom: 0.4rem;
}

.demo-field input {
    width: 100%;
    padding: 0.65rem 0.9rem;
    border-radius: 10px;
    border: 1px solid var(--border);
    background: var(--bg-accent);
    color: var(--text-primary);
    font-size: 1rem;
    font-family: 'Inter', sans-serif;
    transition: var(--transition);
}

.demo-field input:focus {
    outline: none;
    border-color: var(--accent);
}

.demo-results {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}

.demo-result {
    background: var(--bg-accent);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 1.25rem;
    text-align: center;
}

.demo-result .label {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-dim);
    margin-bottom: 0.4rem;
}

.demo-result .value {
    font-family: 'Outfit', sans-serif;
    font-size: 1.6rem;
    font-weight: 700;
    color: var(--text-primary);
}

.demo-result.highlight {
    border-color: var(--accent);
}

.demo-result.highlight .value {
    color: var(--accent);
}

.demo-greeks {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 0.75rem;
    margin-top: 1rem;
}

.demo-greek {
    background: var(--bg-accent);
    border-radius: 10px;
    padding: 0.9rem;
    text-align: center;
}

.demo-greek .label {
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-dim);
    margin-bottom: 0.25rem;
}

.demo-greek .value {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-secondary);
}

/* ─── Responsive ─── */
@media (max-width: 768px) {
    .nav-toggle {
        display: flex;
    }

    .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        flex-direction: column;
        background: rgba(5, 7, 10, 0.95);
        backdrop-filter: blur(var(--glass-blur));
        padding: 1rem;
        border-bottom: 1px solid var(--border);
    }

    .nav-links a {
        padding: 0.75rem 1rem;
    }

    .main-nav.open .nav-links {
        display: flex;
    }

    .hero h1 {
        font-size: 2.6rem;
    }

    .hero {
        min-height: 90vh;
        padding-top: 6rem;
    }

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

    .page-header h1 {
        font-size: 2rem;
    }

    .demo-inputs {
        grid-template-columns: 1fr;
    }

    .demo-greeks {
        grid-template-columns: repeat(2, 1fr);
    }

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

    .contact-alt {
        flex-direction: column;
        align-items: center;
    }
}

/* Tooltip Interactive */
.tooltip {
    position: absolute;
    top: 0;
    left: 0;
    opacity: 0;
    pointer-events: none;
    z-index: 9999;
    background: rgba(17, 25, 40, 0.9);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid rgba(255, 255, 255, 0.15);
    color: var(--text-primary);
    padding: 0.75rem 1rem;
    border-radius: 8px;
    font-size: 0.85rem;
    max-width: 280px;
    line-height: 1.4;
    transition: opacity 0.2s ease-in-out;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.5);
    text-align: center;
}

.tooltip.visible {
    opacity: 1;
}

.tooltip-trigger {
    cursor: help;
}